American Scientist - Cyber Insecurity

Contents | Zoom in | Zoom out For navigation instructions please click here Search Issue | Next Page 

 

 

 

 

 

 

AMERICAN 

 

 

 

______________________ 

Cyber-Insecurity 

The latest digital threats 

call for a smarter, 

stronger response. 

 

Contents | Zoom in | Zoom out For navigation instructions please click here Search Issue | Next Page

American Scientist 

Previous Page | Contents | Zoom in | Zoom out | Front Cover | Search Issue | Next Page 

qM 

qM q 

qM q 

M 

M 

Qmags 

THE WORLD’S NEWSSTAND ® 

Join Us in Atlanta! 

You’re invited to Sigma Xi, The Scientific Research Society’s 

2016 Annual Meeting and Student Research Conference! 

Both events will be held at the Hyatt Regency Atlanta 

November 10–13 in Atlanta, Georgia, USA. 

Register by May 27 to save 20 percent! 

Attend workshops and panels on science 

communication, mentorship, entrepreneurship, science 

careers, and science policy. 

Engage with eminent scientists presenting at the new 

Sigma Xi Research Symposium. 

Meet and greet students and research professionals at 

the new STEM mixer. 

Volunteer to judge research presentations by graduate, 

undergraduate, and high school students on November 12 

at the Student Research Conference. 

Enjoy keynote sessions by Sigma Xi’s award winners. 

www.sigmaxi.org/meetings-events/annual-meeting 

#SigmaXimtg 



qM 

qM q 

qM q 

M 

M 

Qmags 

THE WORLD’S NEWSSTAND ®



qM 

qM q 

qM q 

M 

M 

Qmags 


AMERICAN 

 

 

Departments 

130 From the Editors 

131 Letters to the Editors 

134 Spotlight 

Flint water crisis lessons Science 

in Cuba Briefings 

140 Sightings 

Staining a fish’s armor 

144 Infographic 

Year one of our new view of Pluto 

146 Perspective 

The imprecise search for 

extraterrestrial habitability 

Kevin Heng 

150 Engineering 

Traffic signals, dilemma zones, and 

red-light cameras 

Henry Petroski 

154 Computing Science 

Why cybersecurity is harder than 

building bridges 

Peter J. Denning and 

Dorothy E. Denning 

Scientists’ 

Nightstand 

180 Book Reviews 

Behind the scenes in laboratory 

science The war on rust The 

search for the origins of life Explore 

space with Professor Astro Cat 

From Sigma Xi 

189 Sigma Xi Today 

Geometry lessons on cereal boxes 

High school virtual chapter Claude 

C. Barnett GIAR endowment fund 

Takeaways on engaging more African 

Americans in STEM 

The Cover 

Feature Articles 

158 Energy–Water Nexus: Head- 

On Collision or Near Miss? 

Increasing power demand and 

decreasing water supplies are 

intertwined issues. 

Kristen Averyt 

166 Paradoxes, Contradictions, 

and the Limits of Science 

Many research results define what 

cannot be known, predicted, or 

described. 

Noson S. Yanofsky 

174 The Many Faces of Fool’s Gold 

Pyrite may be worthless to gold 

miners, but it finds great use in 

industry. 

David Rickard 

166 

158 

At any given moment, millions of computing systems connected to the Internet are fending off attacks. Security software company Kaspersky 

Labs has created a real-time global map of cyberthreats that its security network is subjected to (see _________________ 

https://cybermap.kaspersky.com). This image, 

showing recent attacks over the span of seconds, centers on Europe and Asia, which contain countries often on the top-10 attacked list. (The order 

changes, but Russia is often first, followed by the United States. Germany is sixth and France is seventh.) Colors in the attacks indicate how the 

threat was discovered—through a user’s regular screening (red), or in a sweep brought on by a suspicious email attachment (blue), for example. 

Lines follow the threat from its point of discovery to other places on the globe that are being attacked by the same threat. In “Cybersecurity Is 

Harder than Building Bridges” (Computing Science, pages 154–157), Peter J. Denning and Dorothy E. Denning examine why the protection of 

cyber systems is such a complicated, messy problem, compared with other large-scale engineering endeavors. (Image courtesy of Kaspersky Lab.) 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


FROM THE EDITORS 

The Path to Self-Actualization 

Did Albert Einstein achieve his full potential? 

I’ve been pondering this question since his 

100-year-old prediction of the existence of gravitational 

waves was confirmed this past February. 

After a decades-long search, astrophysicists at the 

Laser Interferometer Gravitational-Wave Observatory 

(LIGO) triumphantly detected ripples in the 

curvature of spacetime. These disruptions, which 

occurred after a collision between two distant black 

holes, precisely validated Einstein’s calculations. 

Although it’s inspirational that his work continues to 

shape our view of the universe, I’ve often wondered 

whether Einstein was satisfied with his legacy. 

Born into an Ashkenazi Jewish family in 1879, Einstein dealt with many personal 

challenges: unsupportive teachers, inability to land a teaching job after graduation, 

anti-Semitic backlash to his theories, and ongoing difficulties with romantic 

relationships. It’s reasonable to think that the energy spent overcoming these obstacles 

detracted from his personal satisfaction. He was, after all, only human. 

To gain insight, I looked into the concept of self-actualization. In 1954, psychologist 

Abraham Maslow expressed a theory of human development that explains 

what factors influence people’s ability to achieve their potential. At the core of this 

theory is the suggestion that we strive to fulfill basic needs before pursuing our 

higher-level needs. 

Models depicting Maslow’s theory often consist of 

five hierarchical levels within a pyramid. The base of 

the pyramid represents physiological needs, such 

as food, water, and sleep. Protection from the 

elements, order, and security are among the 

safety needs at the second level. The third 

and fourth levels relate to love, acceptance, 

and confidence. After satisfying these 

basic needs, we are free to pursue our 

fifth-level personal growth and fulfillment 

needs; only then are we 

fully realized. 

As it happens, Einstein was one of 18 subjects whose works and accomplishments 

were studied by Maslow in order to develop his original characteristics of 

self-actualization. Maslow determined that, despite personal setbacks, Einstein 

represented an objectively self-actualized individual. Here, too, he was a source of 

inspiration. 

Several of the articles in this issue cover scientific work relating to the needs 

in Maslow’s hierarchy. In “Energy–Water Nexus: Head-On Collision or Near 

Miss?” (pages 158–165), Kristen Averyt addresses our physical need for energy 

and clean water and how to sustain them in the future; in “Cybersecurity Is 

Harder Than Building Bridges” (pages 154–157), Peter and Dorothy Denning 

address security needs by offering a path to a safer, more reliable Internet; and 

in “The Imprecise Search for Extraterrestrial Habitability” (pages 146–149), Kevin 

Heng looks at how needs might be satisfied for beings on other worlds. Our 

Spotlight interview with Marc Edwards, the engineer that led the Flint Water 

Study, details how scientists failed to protect the needs of the citizens of Flint 

and provides the steps we can take to avoid similar errors in the future. Heeding 

Edwards’s advice will help us all to be more self-actualized. 

As for a response to my opening question, it turns out that Einstein provided 

his own answer on his last day of life, stating, “I have done my share; it is time to 

go.” We should all be so fortunate. —Jamie L. Vernon (@JLVernonPhD) 

FireflySixtySeven/Wikimedia Commons 

AMERICAN 

Scientist 

www.americanscientist.org 

_______________ 

VOLUME 104, NUMBER 3 

Editor-in-Chief Jamie L. Vernon 

Senior Consulting Editor Corey S. Powell 

Managing Editor Fenella Saunders 

Digital Features Editor Katie L. Burke 

Contributing Editors Sandra J. Ackerman, 

Marla Broadfoot, Catherine Clabby, Brian Hayes, 

Anna Lena Phillips, Diana Robinson, David 

Schoonmaker, Michael Szpir 

Editorial Associate Mia Evans 

Art Director Barbara J. Aulicino 

SCIENTISTS’ NIGHTSTAND 

Editor Dianne Timblin 

AMERICAN SCIENTIST ONLINE 

Digital Managing Editor Robert Frederick 

Publisher David Moran 

ADVERTISING SALES 

 

___________ 

EDITORIAL AND SUBSCRIPTION 

CORRESPONDENCE 


P.O. Box 13975 

 

 

 

____________ 

________ 

PUBLISHED BY SIGMA XI, THE SCIENTIFIC 

RESEARCH SOCIETY 

President Mark Peeples 

Treasurer Ronald Millard 

President-Elect Tee Guidotti 

Immediate Past President George Atkinson 

Interim Executive Director John C. Nemeth 

COMMITTEE ON COMMUNICATIONS AND 

PUBLICATIONS 

James Baur, Marc Brodsky, Thomas Kvale, Dennis 

Meredith (chair), Antonio Pita, and Andrew Velkey 

American Scientist gratefully acknowledges 

support for “Engineering” through the Leroy 

Record Fund. 

Sigma Xi, The Scientific Research Society is an 

honor society of scientists and engineers, founded 

 

diverse organization of members and chapters, 

the Society fosters interaction among science, 

technology, and society; encourages appreciation 

and support of original work in science and 

technology; and promotes ethics and excellence 

 

Printed in USA 

130 American Scientist, Volume 104 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


LETTERS 

Microgravity’s Hottest 

To the Editors: 

Thanks to the authors Indrek S. Wichman, 

Sandra L. Olson, Fletcher J. Miller, 

and Ashwin Hariharan for their 

study “Fire in Microgravity” (January– 

February). I have one small correction 

to suggest regarding the hottest region 

of a reduction flame. 

The beautiful color photographs 

of microgravity candle flames reveal 

interesting details about low-gravity 

flames. In general, their spherical 

shape is indicative of uniform inward 

and outward gas flow through the 

flame’s surface with no shape distortion 

resulting from macrogravityinduced 

convection. In particular, they 

reveal the energy profile of reducing 

flames, which suggest that the yellow 

area of a candle flame is not its hottest 

region. In both micro- and macrogravity, 

the fuel is stationary as oxygen 

diffuses slowly through the flame 

boundary. Some oxygen molecules 

escape back into the flame’s exterior, 

and the remainder is consumed internally, 

leaving excess unconsumed 

carbon. The steady state density 

of oxygen is highest as it enters the 

flame, where it produces a thin shell 

of purple emission at the 

flame boundary, which 

is thicker in the lower, 

purple region in convective 

flow. The rate of 

energy release per unit 

volume is highest in this 

thin region as inferred 

by the presence of shortwavelength, 

high-energy 

photons, indicating 

the highest temperature 

in the flame. The yellow 

light is generated mostly 

by blackbody radiation 

from carbon atom clusters in the upper, 

cooler part of the flame. The elongated 

microgravity flame thins the 

flame’s upper boundary, increasing 

the flame’s surface-to-volume ratio 

and making it easier for unconsumed 

soot particles to escape into the neighboring 

gas sweeping the microgravityflame’s 

surface. Other interesting 

features are revealed in these photographs 

as well. 

Ed Sickafus 

Grosse Ile, MI 

Drs. Wichman, Olson, Miller, and 

Hariharan respond: 

NASA 

We appreciate Dr. Sickafus’s perspicacious 

comments, which are largely 

correct. Indeed, the hottest part of the 

flame, especially for the 1-g flame with 

“macrogravity-induced convection,” 

is not the yellow (soot) region. It is the 

blue to purplish region, where most of 

the heat-releasing chemical reactions 

occur, whereas the yellow regions are 

somewhat cooler blackbody emissions 

from small soot particulates. (Just to be 

clear, the soot region is still very hot!) 

Soot particulates are normally 

formed when the local combustion 

conditions are fuel rich, meaning that 

there is more fuel than necessary for 

complete combustion. As a result, the 

American Scientist (ISSN 0003-0996) is published bimonthly by Sigma Xi, The Scientific Research Society, P.O. Box 13975, Research Triangle Park, NC 27709 (919-549-0097). Newsstand single copy 

$5.95. Back issues $7.95 per copy for 1st class mailing. U.S. subscriptions: one year $30, two years $54, three years $80. Canadian subscriptions: one year $38; other foreign subscriptions: one year $46. 

U.S. institutional rate: $75; Canadian $83; other foreign $91. Copyright © 2016 by Sigma Xi, The Scientific Research Society, Inc. All rights reserved. No part of this publication may be reproduced by 

any mechanical, photographic or electronic process, nor may it be stored in a retrieval system, transmitted or otherwise copied, with the exception of one-time noncommercial, personal use, without 

written permission of the publisher. Second-class postage paid at Durham, NC, and additional mailing office. Postmaster: Send change of address form 3579 to Sigma Xi, P.O. Box 13975, Research 

Triangle Park, NC 27709. Canadian publications mail agreement no. 40040263. Return undeliverable Canadian addresses to P. O. Box 503, RPO West Beaver Creek, Richmond Hill, Ontario L4B 4R6. 

Discover CUBA! 

A People-to-People exploration of Cuba 

with a Botanical Slant November 4-13, 2016 

We invite you to travel 

the World with Sigma Xi! 

 

 

 

 

 

 

 

For information please contact: 

Betchart Expeditions Inc. 

17050 Montebello Road 

Cupertino, CA 95014-5435 

(800) 252-4910 (408) 252-1444 

SigmaXiInfo@betchartexpeditions.com 

betchartexpeditions.com 

____________________________ 

__________________ 

 

 

www.americanscientist.org 2016 May–June 131 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


ONLINE @ 

Evolution of Sleep 

Evolutionary anthropologist 

Charles Nunn of Duke University 

thinks there are three particular 

ways that natural selection has 

made our sleep different from 

that of other great apes. Learn 

more in this podcast: 

http://bit.ly/22Sr7Qx 

A Glimpse of Infinity 

Infinite mathematics, long 

thought to be impossible to 

observe, manifests in optical 

vortices. Physicist Gregory Gbur 

elaborates in this guest blog post: 

http://bit.ly/1RMyy0v 

Entomology Trends in Southeast 

At a regional meeting of entomologists, 

researchers covered 

emerging topics from taxonomy 

to ecology to microbiomics. Matthew 

Bertone of North Carolina 

State University summarizes 

them in this guest blog post: 

http://bit.ly/1VbooLQ 

Historian Critiques Eric Lander’s 

Controversial Cell Paper 

The rise of the gene editing system 

CRISPR-Cas9 was so rapid 

that it has ignited a “craze.” But 

how reliable is Eric Lander’s historical 

description of “the heroes of CRISPR”? 

Historian of science and biologist 

Michel Morange of the École Normale 

Supérieure in Paris gives his opinion 

in this guest blog post: 

http://bit.ly/1M3HJx7 

Dance: It’s Only Human 

Two Oxford University evolutionary 

psychologists, Robin Dunbar and Bronwyn 

Tarr, think that what humans get 

from dancing with one another is the 

same thing that chimpanzees get from 

grooming one another. Listen to their 

observations in this podcast: 

http://bit.ly/1SC8ubg 

Engaging African Americans in STEM 

In this video Q&A, Ashanti Johnson, 

Melanie Harrison Okoro, and Danielle 

Lee chat about effective strategies for 

engaging African Americans in science: 

http://bit.ly/1Y2ovsm 

Playing Sports in Hyperbolic Space 

Mathematician Richard Canary of 

the University of Michigan discusses 

the mind-twisting math of hyperbolic 

space, a world in which curved lines are 

really straight and parallel. Watch the 

video Q&A or read the live tweets: 

http://bit.ly/1RAgg38 

Check out AmSci Blogs 

http://www.amsci.org/blog/ 

Find American Scientist 

on Facebook 

facebook.com/AmericanScientist 

Follow us on Twitter 

twitter.com/AmSciMag 

Follow us on Google Plus 

__________________ 

plus.google.com/+Americanscientist 

Org/about 

_____ 

Join us on LinkedIn 

__________________ 

https://www.linkedin.com/company/ 

american-scientist 

_________ 

Find us on Instagram 

_________________ 

http://instagram.com/american_ 

_____ scientist/ 

Pin us on Pinterest 

http://www.pinterest.com/amscimag 

Read American Scientist 

using the iPad app 

Available through Apple’s App Store 

fuel molecules breach the flame only to 

later congeal and form soot. We have 

determined that, overall, our spreading 

simulated microgravity flames are 

fuel lean, meaning that combustion 

takes place with an overabundance 

of oxygen. However, it is possible for 

combustion to be fuel lean overall but 

fuel rich locally, as here. 

In the localized region between the 

surface and the flame there is indeed 

more fuel present than will burn with 

the available oxidizer in the time required, 

so some of it is simply heated, 

remains unburned, and congeals into 

soot particulates. The oxygen gets its 

pound of flesh, however, and eventually 

burns off all of the fuel in the yellow 

(sooty) flame downstream of the purplish 

flame. The writer is correct: There 

is much more to be seen besides, which 

speaks to the great advances in optical 

visualization over the past half-century. 

Illustration Credits 

Spotlight 

Pages 138–139 Barbara Aulicino 

Perspective 

Page 148 (top) Barbara Aulicino 

(Data source: NASA, PHL@UPR) 

Engineering 

Page 152 (left) Barbara Aulicino 

Computing Science 

Page 156 Barbara Aulicino 

Energy–Water Nexus: Head-On 

Collision or Near Miss? 

Page 160 Tom Dunne 


(adapted from K. Averyt, et al., 2011; 

J. Rogers, et al. 2013) 



Paradoxes, Contradictions 


Page 168 Robert Kosara 

Erratum 

In “Meat-Eating Among the Earliest Humans” 

(March–April) by Briana Pobinar, 

the text states on page 115 that a zebra 

carcass yields more than 6,000 calories, 

equivalent to 11 Big Macs, enough to meet 

the daily caloric requirements of three 

Homo erectus males. The correct numbers 

are 60,000 calories from a zebra carcass, 

equivalent to almost 107 Big Macs, which 

is enough to meet the caloric requirements 

of about 27 Homo erectus males. 

We have corrected this error online. 

How to Write to American Scientist 

Brief letters commenting on articles 

appearing in the magazine are welcomed. 

The editors reserve the right 

to edit submissions. Please include 

an email address if possible. Address: 

Letters to the Editors, P.O. Box 13975, 

Research Triangle Park, NC 27709 or 

editors@amscionline.org. 

_________________ 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Trusted, Inspired, Educational & Fun 

 

_____________________ 

FREE 

GROUND 

SHIPPING 

on orders $75+ 

USE AMSCI 

Your Trusted S.T.E.M. Resource 

Center for Innovation & Quality 

At Scientifics Direct, we have hundreds 

of science, technology, engineering 

products that ignite the imagination and 

help make learning fun. We specialize in 

hands-on, applied science kits designed 

specifically for learners age 8 to adult. 

From our new Hydraulic Arm 

Robot Kit with six axes of detailed 

movements to our Duino Programming 

Kits with sturdy metal carry cases, 

we have S.T.E.M. related product 

solutions for every need and budget. 

Visit us today at 

ScientificsOnline.com 

Duino Essentials Learning Kit......#3155100 

DuinoKit Jr......#3155318 

14 in 1 Solar Robot 

#3153198 

IQ Key Perfect 600 

#3155217 

Hydraulic Arm Kit 

#3155436 

FIND HUNDREDS OF OTHER UNIQUE 

SCIENTIFIC ACTIVITIES, GADGETS, 

COLLECTIBLES, AND MORE. 

SCIENTIFICSONLINE.COM 

_____________________ 

*Free ground shipping valid through 07/31/16 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Spotlight 

Flint Water Crisis Yields Hard 

Lessons in Science and Ethics 

Like many scientists, Virginia Tech civil engineer 

Marc Edwards chose his career to serve 

the public good. But his experience uncovering 

the Flint, Michigan, water crisis, where 

citizens were exposed to high levels of lead because 

of government and scientific negligence, 

has been a stark reminder of what can happen 

when science is misused or ignored. To make 

matters worse, the Flint water crisis is a repeat 

of very recent history. About a decade ago, 

Edwards revealed high lead levels in public 

water in Washington, DC, exposing misconduct 

at the U.S. Centers for Disease Control 

and Prevention (CDC), U.S. Environmental 

Protection Agency (EPA), and District of Columbia 

Water and Sewer Authority (WASA). 

At the time, in 2003, Edwards was conducting 

WASA-funded research investigating an 

unprecedented number of small leaks in copper water pipes in the 

DC area as well as EPA-subcontracted research on water lead levels. 

He found some lead concentrations in the thousands of parts 

per billion and realized that WASA had given out misinformed 

Engineer Marc Edwards helped expose 

the Flint water crisis. Photograph by 

Jim Stroup, courtesy of Virginia Tech. 

advice about drinking water. But after he notified 

the agency, WASA refused to issue a 

new memo to alert people. Soon after, WASA 

threatened to withhold the results from his 

sampling program as well as $110,000 of 

funding he had recently proposed, unless he 

stopped the studies of water in local homes. 

Edwards refused, and the EPA terminated his 

subcontract. Edwards continued his research, 

paying his team out of his own pocket when 

he had to. In March 2004, the CDC published 

a report that concluded that the lead levels 

from blood tests of DC children were not high 

enough for concern. After congressional hearings, 

the EPA ruled later in 2004 that WASA 

violated federal regulation. In 2009 congressional 

hearings, the CDC report was found to 

be flawed, because it left out samples, a fact 

that had come to light after Edwards reanalyzed the full data set. 

Digital features editor Katie L. Burke interviewed Edwards about 

his experiences and how he is working to prevent another incident 

like the ones in Flint and DC. 

Studies by you and others have 

now shown that tens of thousands 

of homes in Washington, DC, had elevated 

levels of lead in their water. 

Lead levels in some water samples 

you tested were so high that they 

could be classified as hazardous 

waste. How could scientists and regulatory 

agencies let that happen? 

The DC water crisis was the most fundamental 

betrayal of the public trust 

and scientific integrity in black and 

white that I have ever seen or even 

heard of, having reviewed case study 

after case study. With no profit motive 

whatsoever, these people [those in leadership 

positions at WASA, EPA, and 

CDC] poisoned an entire city, covered 

it up completely, and made sure that 

these kids and their families never even 

got a penny to help with the extra educational 

needs that they have [as a result 

of the poisoning]. It took me working 

as a volunteer crazy person for six 

years to prove that kids were hurt. 

Five people [Seema Bhat, Jim Bobreski, 

Sue Kanen, Jerome Krough, and 

Ralph Scott] put their professional lives 

on the line in DC. They were fired. Two 

won whistleblower lawsuits, but no 

one really ever thanked these people. 

The perpetrators and the federal government 

who caused the DC lead crisis 

covered it up every step of the way. 

If it comes down to a decision between 

their reputation and the truth, 

the truth will lose every single time 

with these agencies, because they are 

not rewarded for being loyal to the human 

race. They’re rewarded for being 

loyal to their agency. That’s the kind of 

people we have, unfortunately, in positions 

of power. 

How can the agencies prevent another 

DC or Flint water crisis? 

If you ever want to know why something 

like Flint happens, you only have 

to look at how we destroy good people 

and promote weak, unethical cowards. 

At that point, it’s just what you expect. 

We should expect more Flints in the 

future unless we get the system fixed. 

What have you found to be the 

most effective way to reach people 

when you talk about failing public 

infrastructure that is underfunded? 

If you look at every projection of the 

federal budget, due to mismanagement 

and entitlement, discretionary 

spending is going down. That’s happening 

at the federal, state, and local 

level. We are in an era where the pie is 

getting smaller. That is going to create 

unprecedented pressure on all aspects 

of science and engineering. It’s going 

to pressure us to be unethical in some 

situations to make sure we get our positions 

taken care of. We have to prioritize 

like we never have before. 

What do we value as a society? From 

my perspective, critical infrastructure, 

you have to advocate for that, because 

without it, civilization is lost. That’s 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Logan Wallace 

what happened in Flint. They lost their 

ability to get clean water. People left 

town. This happened in Rome roughly 

two millennia ago. When the aqueducts 

no longer functioned, Rome lost 

95 percent of its population. A civilization 

can literally end if you don’t invest 

in these priorities. 

I think we also have to be aware that 

this is a prioritization process. We have 

to engage in these debates and fully 

realize that there are other priorities for 

the shrinking pie. Education is getting 

the short end of the stick as well. You 

have to have some humility about that, 

look at the economic realities, and try to 

do more with less. It’s the ultimate science 

and engineering challenge to still 

serve mankind, even though the fiscal 

reality is that we’re not going to get 

increased funding and in all likelihood 

we’re going to get less. 

You now have a reputation as a 

whistleblower. Have you always had 

a skeptical attitude toward the research 

establishment? 

Before my experiences in DC, I was 

incredibly naive. I was about 40 years 

old, and I didn’t know anything about 

the history of scientific misconduct. 

I hadn’t even accepted the idea that 

scientists at federal agencies with no 

profit motive whatsoever would behave 

unethically. I think a lot of America 

is just waking up to that possibility 

based on what we exposed in Flint. 

It was very difficult for me to accept, 

because I was to some extent willfully 

blind, in retrospect. I was a danger to 

myself and others, because I didn’t really 

understand the dark side of science, 

which is the dark side of humans. We’re 

all imperfect, and humans can screw 

up anything. Growing up worshipping 

at the altar of science, if you will, and 

thinking of science just as a good, and 

thinking that if I’m a scientist or engineer 

then I’m by definition doing good. 

The idea that science might be used for 

bad in a Western democracy hadn’t really 

entered into my mind-set. 

What went through your head as 

you began to realize that government 

scientists were lying? 

It was an extremely traumatic experience 

for me to learn this the hard way, 

to see that corrupt officials couldn’t care 

less about facts and scientific truths if it 

meant protecting their reputation or advancing 

their agency’s agenda. At one 

point I’d lost about 30 pounds when I 

realized what the EPA was up to. My 

heart started racing, and I told my wife, 

“I’m going to die.” I told her goodbye. 

Thankfully, I didn’t die. I’m sure some 

people out there wish I had. 

Do you think you would have been 

better off in your early career if you’d 

been more aware of the likelihood of 

encountering scientific misconduct? 

You can really mess yourself up, I 

think, just from being that naive and 

uninformed. It’s a real problem that 

we as scientists aren’t aware of our 

history. We’re not taught about how 

everything human about us can push 

us to do unethical things. We face 

 

 

 

 

 

 

 

 

 

those pressures day in and day out, 

and it’s only by properly using the scientific 

method and honoring it that 

we can stop ourselves from reaching 

the wrong conclusions that hurt 

people. Science really is this amazing 

tool that if it’s done properly you will 

more often than not reach the correct 

conclusion, which is important, I hope 

we would all agree. But to the extent 

that you let down your guard and 

lack moral humility, you will wake up 

some day having done something horrible, 

even though you started down 

this path with the best of intentions. 

Why and how do these scientists end 

up hurting rather than helping the 

public with their flawed research? 

I believe that the vast majority of scientists 

entering the profession from high 

school, based on my personal observation, 

view science as a public good and 

a force to create a better world. Gradually, 

if you look at our educational 

institutions and the workplace, what 

happens is we are taught to become 

willfully blind. We’re taught to become 

cynical. We’re taught that we can’t do 

better than the status quo, and that if 

this agency’s corrupt, there’s nothing 

we can do about that. We feel powerless. 

We become part of the problem. 

This all happens naturally, to the 

point that a lot of people end up becoming 

something that they once 

abhorred. They become people who 

practice science and engineering and 

end up harming people. 

You now co-teach with anthropologist 

Yanna Lambrinidou an ethics 

class at Virginia Tech called Engineering 

Ethics and the Public. How 

do you approach mentoring future 

scientists in this class to help them 

avoid these pitfalls? 

We have to tell people that heroism is 

difficult. Otherwise, everyone would 

be doing it, and it wouldn’t be heroism. 

It’s our experience and our hypothesis 

in the class, Dr. Lambrinidou’s 

and mine, that ethics instruction 

in this country is 100 percent wrong 

in how it’s approached. It is presented 

as if “you know the rules, and we’re 

going to teach you them. Then, if you 

follow them, everything will turn 

out just fine.” It’s like a chess game, 

and if you know the rules, you’ll win. 

That’s not the real world. Real-world 

ethical dilemmas are gut-wrenching, 

life-changing experiences that require 

you to put yourself in harm’s way to 

do the right thing. What class in ethics 

is teaching students that fact? We try to 

instill ethical street-smarts in students. 

What we do in the class is make sure 

people understand who they are, what 


2016 May–June 135 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


they stand for, where they will draw 

the line, and to write that down at this 

early point in their career. We put them 

in real-world situations where everything 

is pushing them to do the wrong 

thing. They see how strong a person 

you have to be to uphold scientific 

integrity. They come away realizing, 

“Wow, this is not easy to remain ethical 

in a perverse incentive structure.” 

We go through case studies that show 

how heroic actors do the right thing, 

put their career on the line to protect 

the public, and are fired. 

One of our best examples is what 

we call the press conference. We have 

each student role-play that they’re 

one of the agencies that was involved 

in perpetrating and covering up the 

Washington, DC, lead crisis. We give 

them briefing materials that tell each 

agency what they know at that moment 

in time and how their agency 

owns a little piece of this problem because 

of their past mistakes. We then 

let them know the public is angry. In a 

few days they’re going to give a press 

conference and answer questions. 

When we do that, nine times out of 

ten the students find themselves lying. 

It’s fascinating. We then play the videotape 

from the actual people at the press 

conferences telling the exact same lies. 

They very quickly learn that telling the 

truth is not necessarily your first inclination. 

Throughout the semester they 

get to see how a half lie turns into a 

bigger lie, which turns into a bigger 

lie, until eventually you create the epic 

examples of scientific misconduct. 

The Washington, DC, lead crisis goes 

on to this day. Kids that were hurt might 

get their day in court next summer, at 

which point they’re out of high school. 

Once you’ve lived through those 

kinds of experiences, you realize that 

you have to work very hard to be ethical. 

You gain moral humility, which 

is necessary in science and engineering. 

You’re only one bad mistake from 

becoming someone that you once 

would’ve been disgusted by. 

Do we need to change the stories 

we tell ourselves and others about 

what it takes to be a good scientist? 

It’s interesting who we glorify in science 

and how divorced from reality it 

is. If you consider the typical stereotype 

of heroism in science, it’s about a path 

 

 

 

 

 

 

 

 

where someone makes a discovery 

through hard work, creates something 

of tremendous value for the world, and 

they bestow this gift on the world and 

receive rewards. It feeds the virtuous 

cycle between science and the public. 

Who are we putting forward as heroes 

for students to follow? I believe 

that currently who we make the role 

models in our field, it’s very narrow. 

It is the people who’ve achieved the 

goals of the perverse incentive structure. 

Who do we point to for students 

to emulate? Well, it’s the person who’s 

got the big multimillion-dollar center 

and is getting all the money, getting 

all the publications, is at the top of this 

pyramid supporting all these researchers. 

Is that the modern hero of science? 

I guess so, but not to me. 

My heroes are people whose story 

you might not even know. For example, 

Peter Buxtun exposed the Tuskegee experiment 

(Buxtun was an epidemiologist 

once employed by the U.S. Public Health 

Service (PHS), who acted as a whistleblower 

in 1972 to expose an experiment that 

studied the natural progression of syphilis, 

which became treatable during the course 

of the 40-year experiment, in hundreds of 

poor African-American men under the auspices 

of free health care). He fought for 

five years to get the PHS to stop this 

horrific human experiment. He went 

through two review panels, fighting, 

and those panels each time told him 

to go do something else because they 

felt there was nothing wrong with the 

Tuskegee experiment. He didn’t give 

up. It wasn’t until it got into the press 

and there was a congressional hearing 

that folks in positions of power at PHS 

realized, “Wow, this really looks bad. 

People are mad at us.” As a result, we 

now have institutional review boards 

and human subjects training. To me, he 

went the true hero’s journey. 

Researchers speaking out 

about science’s dark side 

are often warned that 

doing so can be dangerous, 

because it feeds antiscience 

rhetoric. How do 

you respond? 

Well, the same logic applied 

in the Catholic Church when 

pedophilia was rampant, we 

now know, and people were 

stopped from calling it out. 

Folks in positions of power 

were saying, “This is going to 

hurt the church. This is going 

to hurt our reputation.” I understand 

where they’re coming from. I don’t get 

any pleasure from talking about this. 

The people in the Catholic Church who 

were whistleblowers did not get pleasure 

from pointing out that their colleagues 

were pedophiles. But what is 

the cost of not speaking out? The cost is 

people get hurt. The cost is you end up 

damaging the institution you love even 

more. It wasn’t until the public learned 

about it that they finally had no choice 

but to get this fixed. 

Who loves science more: the people 

who are willfully blind and are fearful 

of talking honestly about our problems, 

or someone who loves it so much that 

they’re willing to try to fix it? No one 

loves science and engineering more 

than me. No one loses more sleep over 

what I’ve had to do than me. It kills me 

to speak out, but I am not going to sit 

by and let more people get hurt. I’m 

not going to let the institution of science 

and engineering go down this path if I 

have a word to say about it, because all 

humanity, all civilization, rests on scientists 

and engineers doing their jobs, 

and we cannot do our job if we are not 

trustworthy. I’m frankly more fearful 

about what will happen if I don’t speak 

out than if I lose my career. 

Jim Stroup 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Moving Forward After Flint 

Siddhartha Roy is a graduate student at Virginia Tech in Marc Edwards’s lab, and as 

the communications director for the Flint Water Study, he interacted with residents there 

to uncover the Michigan city’s water contamination problems. In spring 2015, LeeAnne 

Walters, a mother of four in Flint who was concerned her water had high levels of lead, 

contacted Marc Edwards about testing for lead in her water after the city’s water utility had 

dismissed her concerns. On April 28, Edwards, Roy, and their team found that Walters’s 

water had lead levels as high as 13,200 parts per billion, 880 times the U.S. Environmental 

Protection Agency’s actionable limit for lead concentrations in drinking water. Roy and his 

labmates dropped other research projects to focus on testing water for Flint’s residents as 

quickly as possible. They sent lead test kits to local households and traveled from Virginia 

to Michigan to collect samples. As their data came in, they called households whose water 

showed risky levels of lead to warn them about drinking it. Research now shows that more 

than 9,000 kids were exposed to elevated lead levels; there was also a spike in cases of 

Legionnaires’ disease as corrosion neutralized the chlorine used to keep the drinking water 

safe. Here, Roy explains in his own words how this work has affected his outlook on science 

and his career, as told to digital features editor Katie L. Burke. 

Siddhartha Roy is a doctoral student in 

Marc Edwards’s lab. Photograph by Jim 

Stroup, courtesy of Virginia Tech. 

Logan Wallace 

Initially, I thought of agencies as 

people, especially for agencies 

such as the Michigan Department 

of Environmental Quality (MDEQ) 

or the U.S. Environmental Protection 

Agency (EPA), because they have policies 

that are based in science. For example, 

initially when we [Edwards’s lab] 

said there’s a lead problem, the MDEQ 

said, “Our sample results show different.” 

That’s OK, because in science you 

welcome skepticism. The kind of attacks 

that this science-based regulatory 

agency made on us and then made on 

the Flint doctor Mona Hanna-Attisha 

when she came out with her blood 

lead results of Flint’s children was jawdropping. 

They said things like, “Oh, 

the Virginia Tech group specializes 

in looking for lead problems 

in water. They pull that rabbit out 

of the hat wherever they go.” 

Then a memo by an EPA scientist 

was leaked showing high 

lead levels [in Flint’s water]. The 

mayor of Flint reached out to the 

administrator of EPA Region 5, 

Susan Hedman, and asked her, 

“Is there a problem with lead in 

my city?” She apologized for the 

memo being leaked, said it was 

a draft and it will be vetted. This 

was in July 2015, and the final memo 

came out in November. She sat by just 

as MDEQ spewed lie after lie that the 

water was safe to drink and met all 

state and federal standards. The top 

regulatory cop in the area, Region 5 

EPA, did nothing. MDEQ first off lied 

to the EPA, saying there was corrosion 

control, and then it said there was none 

and still did nothing. 

When we came in with our results [on 

lead levels in Flint in August 2015] we 

were openly discredited in the media by 

the state agency [MDEQ]. For a couple 

of days it seemed like, “Oh my gosh, 

we spent so much money and time and 

even cried on phone calls telling people 

that the water is not safe and listening to 

their stories, and nothing’s going to happen 

because the state insists everything 

is fine.” We knew what we were doing 

was right. People were at least starting 

to know that there’s a lead problem, so 

they could take steps to protect themselves. 

That sense of connection helped 

 

 

 

strengthen our resolve and gave us the 

strength to work 18-hour days. 

When we started calling people with 

their lead results, I wrote a script to 

make sure I gave them all the information 

they needed. But that’s not how 

real conversations work. People told us 

their stories, told us about how someone 

in the family’s sick. Or when I told 

them, “You can buy a lead filter,” I’d 

be asked, “How much is a lead filter?” 

I’d say, “$30 to $40,” and I’d hear back, 

“Oh, I live on social welfare. There is 

no way I can afford $30 to $40 in at 

least the next two months.” There are 

times we felt so helpless that we did 

not know what to do. 

A grad student in our lab, Anurag 

Mantha, couldn’t take it anymore. 

He set up an online fundraising 

campaign—the first in this whole 

saga. He was the first to donate. He 

was like, “I don’t care. I’m a poor grad 

student, but I’m putting money in for 

this.” That set a precedent, and about 

two weeks later there were hundreds 

of thousands of dollars being raised in 

the city for residents. I think what this 

shows is when you are a scientist with 

expertise, that is not all you can give. 

You can also be a compassionate ear, 

listening to people’s stories. 


2016 May–June 137 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


People [in Flint] kept protesting for 

months and months. They were arrested 

in public meetings. It is just mindboggling 

to see how people have been 

mistreated for something as basic as 

drinking water, which everyone should 

have a right to. 

How Could This Happen? 

I don’t think anyone wakes up thinking, 

“Today I’ll poison some kids with 

lead.” But many of these officials are 

people from my field, and they have 

been working in it for decades. Often 

when we look at numbers in an Excel 

sheet, they just seem like numbers. 

But for us, behind every number was 

a family. When you’re trying to meet 

2014 2015 

regulations, it’s easy to forget that, 

which I think is partly why these people 

did what they did. 

To imagine them not following federally 

mandated corrosion control— 

 

 

 

 

 

 

for them to be using faulty sampling 

protocols and throwing out data to 

meet a regulation when people’s lives 

are at stake—it is just unconscionable. 

It shows the arrogance and just plain 

disregard for public health that many 

of these officials had. That is apparent 

in how they reacted to people questioning 

the safety of their tap water. 

The only job that these people have 

is to protect the public, and they end 

up doing everything but that. While 

there are allegations about which politicians 

knew what and why they did 

not act sooner, I think it’s clear that 

both the MDEQ and EPA are guilty of 

not doing their job and sitting by silently 

as people were poisoned. 

When I applied to graduate 

school, my idea of working 

in environmental engineering 

was to help people. 

When I talked to other people 

in my field, they look at 

the work of scientists as making 

groundbreaking discoveries, 

but they don’t interact 

much with the public. Flint 

showed us the value of looking 

at science as a force for 

public good, which was originally 

why the federal and 

state governments funded 

basic and applied research. 

The goal of most research should be 

bettering the human condition. That’s 

what has happened in the past 200 

years. The quality of life we enjoy has 

been because of scientists, and their 

work has immensely benefited society. 

Many of us forget why we come 

into research in the first place. Flint has 

strengthened my human perspective 

and made me more comfortable with 

emotion in science. I don’t look at it as 

an impediment to doing good science, 

as has been traditionally thought. Flint 

Jake May/AP Images 

APRIL 

SEPTEMBER 

OCTOBER 

April 25: Flint changes its 

water source from Detroit 

Water and Sewerage 

Department to the Flint River. 

September 5: City of Flint 

advises residents to boil 

water due to high levels of 

coliform bacteria. 

October 13: General Motors 

shuts off Flint water in a local 

engine plant because of 

corrosion concerns. 

JANUARY 

FEBRUARY 


January 2: A city notice tells 

residents that public water has 

had high levels of trihalomethanes, 

a disinfectant byproduct. 

It says the water is safe to 

drink, except for the elderly or 

immunocompromised. 

January 21: Residents at a 

town hall meeting complain 

the water is causing a variety 

of concerning symptoms. 

February 3: Michigan 

Governor Rick Snyder gives 

$2 million to Flint to improve 

its public water system. 

February 18: Lead levels of 

104 parts per billion (well over 

the EPA limit of 15 ppb) are 

found in the water at the home 

of LeeAnne Walters. The city 

offered to connect her home 

to a neighbor’s water line. 

February 25: Walters 

contacts a manager at EPA’s 

Midwest water division, 

Miguel Del Toral. 

February 27: Del Toral emails 

the EPA and MDEQ about his 

concerns over Flint’s faulty 

sampling protocol. 

JULY 

JUNE 

APRIL 

MARCH 

March 3: City tests find lead 

levels in water as high as 

400 ppb. 

March 27: Blood tests show 

that all of Walters’s children 

have elevated lead levels in 

their blood. Her four-year-old 

son has lead poisoning. 

April 28: Marc Edwards 

and his group conduct new 

tests on Walters’s water and 

find lead levels as high as 

13,200 ppb, well over the EPA 

limit for hazardous waste. 

June 24: Del Toral writes an 

internal memo (leaked) 

expressing “major concern” 

about the water quality and 

lack of corrosion controls 

in Flint. 

July 1: EPA District 5 

Administrator Susan Hedman 

calls Del Toral’s report 

“preliminary” in an email to the 

mayor of Flint, advising that 

the report will be made public 

when fully vetted (the official 

report doesn’t come out until 

November). 

AUGUST 

SEPTEMBER 

August 13: Edwards’s lab 

sends 300 lead testing kits to 

Flint. 

August 31: The results from 

120 kits analyzed by 

Edwards’s team indicate a 

“serious lead in water 

problem.” 

September 24: Flint 

pediatrician Dr. Mona 

Hanna-Attisha and her team 

release their study on 

elevated blood lead levels 

in children. 

September 25: City of Flint 

issues a lead warning, 

advising residents to drink 

and cook with cold tap water, 

but asserting that the water 

complies with federal 

regulations. The United Way 

starts filter fundraising. 

Ryan Garza/Detroit Free Press/ZUMA , https://share.america.gov 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


gave me genuine new friendships. We 

cannot do science in a vacuum. 

The public is central to how we 

should approach science. Our ultimate 

client is the public. Some of the best 

data that you can get is through listening 

to people, and we often forget that 

because we have gadgets and probes 

that we can take to the field. There is 

also a need for society to acknowledge 

that scientists are people just like everyone 

else. We’re good at social skills. We 

have emotions. When we use it to our 

advantage, great things can happen. 

The Path Forward 

I took Dr. Edwards’s class in my first 

semester, and I’m not exaggerating 

when I say that it changed my life. It 

put into perspective everything that I 

wanted in a career when I say I want 

to help people. The class gave me real 

case studies where people were struggling 

with ethical questions, and the 

answers are not typically black and 

white. Dr. Edwards often says, “It’s 

not a question of if you’ll face an ethical 

dilemma, it’s a question of when.” 

Finding ways to incorporate that kind 

of class into undergraduate education 

would help every aspiring scientist 

understand what is at stake. 

There are two outcomes from Flint 

that I think are critical. One addresses 

public health, the other the water infrastructure. 

Regarding the public health 

aspect, the families, the children who 

have been harmed, need lifelong services 

in terms of education, nutrition, and 

health services. We have to have strong 

programs in place so that their growth 

and their cognitive abilities are monitored 

going forward. (The effects of lead 

exposure are considered irreversible, but access 

to early education can help children 

with developmental delays. Hanna-Attisha 

leads a Pediatric Public Health Initiative for 

the children of Flint: http://humanmedicine. 

_________ 

msu.edu/pphi.) 

In tandem, the government has to 

regain the trust of the people it has deceived. 

We can fix the water infrastructure, 

but replacing the trust that people 

lost is much more challenging. A first 

step, obviously, is apologizing, which 

has happened. We need to acknowledge 

that there was a failure in regulatory 

agencies, and scientists failed us. 

We need to make sure that the culture 

is changed in these agencies. (Federal 

and state investigations are examining 

who is accountable in the Flint crisis.) 

Flint returned to using Detroit water 

back in October, so lead levels are now 

dropping. The damage done to the 

pipes, however, is irreversible. Flint is 

now practicing corrosion control and 

is on noncorrosive water, which will 

2016 

recoat the pipes with orthophosphate 

and reduce the lead release drastically, 

but this is a short-term solution. (Phosphate 

in solution will build up on the inside 

walls of pipes and serve as a barrier 

between the water and the pipe, reducing 

lead’s leaching. The damage to an already 

aging infrastructure, however, reduces the 

pipes’ integrity and lifetime, so they will 

need to be replaced.) Then we can run a 

federally mandated Lead and Copper 

Rule sampling pool to make sure that 

lead levels have dropped to safe levels. 

Even after that, I don’t think people 

[in Flint] will drink their unfiltered tap 

water. Providing filters and addressing 

any water needs that people might 

have in the future are important. 

Long-term, Flint could be a model 

city in how we go about doing pipe 

replacements. There are an estimated 3 

million to 11 million lead pipes in this 

country, which are a legitimate threat 

despite all the federal corrosion control 

practices in place. Flint can be an 

example of how we rebuild. (Replacing 

the estimated 8,000 lead pipes in Flint 

will cost about $55 million, according to a 

plan by Michigan Governor Rick Snyder, a 

price tag that will require state and federal 

support. The EPA has estimated that water 

infrastructure improvements across the 

United States will cost $385 billion over 

the next 15 years.) 

Jim Stroup/Virginia Tech News 

OCTOBER 

NOVEMBER 

DECEMBER 

October 2: A press release 

from Governor Snyder’s office 

says that the water leaving 

the Flint water facility is safe 

but that homes with lead 

plumbing may experience 

unsafe levels of lead. 

October 16: City of Flint 

switches back to Detroit 

Water. 

November 16: Howard Croft, 

head of the Flint Department 

of Public Works, resigns. 

December 9: City starts 

adding orthophosphates to 

water to lower lead levels. 

December 29: Governor 

Snyder apologizes for the Flint 

water crisis, and MDEQ 

Director Dan Wyant resigns. 


JANUARY 

January 5: Governor Snyder 

declares a state of emergency 

for Genesee County. 

January 7: Michigan’s chief 

medical executive advises 

drinking only bottled or filtered 

water in Flint-area residences. 

January 12: Governor Snyder 

sends National Guard troops 

to Flint. 

January 14: U.S. Representative 

Brenda Lawrence 

requests congressional 

hearings to review accountability 

in Flint water crisis. 

January 15: Michigan 

Attorney General Bill Schuette 

launches state investigation of 

Flint water crisis. 

January 16: President Barack 

Obama signs emergency 

declaration. 

January 21: President 

Obama gives $80 million to 

Michigan for Flint. 

JANUARY 

January 21: A Michigan 

Department of Health and 

Human Services report 

assessing Legionnaires 

disease in the Flint area 

brings the total number of 

cases between June 2014 

and October 2015 to 87, with 

9 deaths. 

January 21: EPA Region 5 

Administrator Susan Hedman 

announces her resignation. 

January 26: Flint’s former 

emergency manager, Jerry 

Ambrose, resigns from his 

position on Lansing’s 

Financial Health Team. 

FEBRUARY 

MARCH 

February 3: The first 

congressional hearing of the 

U.S. House Committee on 

Oversight and Government 

Reform is held to examine the 

case of Flint. 

February 5: Governor Snyder 

fires the head of the MDEQ 

Office of Drinking Water, Liane 

Shekter-Smith. 

March 4: Replacement of 

lead service lines in Flint 

begins. 

March 14 and 16: Second 

and third congressional 

hearings of the House 

Oversight Committee. 

March 21: A Flint Water 

Advisory Task Force report 

commissioned by Governor 

Snyder finds that MDEQ 

“bears primary responsibility” 

for the Flint water crisis, but 

also covers the accountability 

that rests with MDHHS, the 

governor, state-appointed 

emergency managers, the 

City of Flint, the Genesee 

County Health Department, 

and the EPA. 

2016 May–June 139 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Sightings 

A Fish’s Armor 

Clearing and staining the scalyhead sculpin reveals defensive solutions that are highly mobile. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


ADAM SUMMERS 

HAS STUDIED the inner 

structures of thousands 

of creatures to see how 

they work. Along the way, 

he’s learned that the most advanced 

imaging techniques are 

not always the most useful ones. 

Dissecting a specimen or using x- 

rays to scan it can reveal a great deal of 

detail, but “there’s only one way to look 

directly at the three-dimensional structure of 

hard and soft tissue without destroying it,” he says. 

That winner is an unglamorous set of chemical steps 

known as clearing and staining. At the University of 

Washington’s Friday Harbor Labs, Summers has refined 

the decades-old approach into a thoroughly modern 

visualization tool. The scalyhead sculpin, Artedius harringtoni, 

shown on this page is a prime result. 

For clearing, Summers used trypsin—a digestive enzyme 

found in your intestines—that attacks most proteins 

but leaves the collagen that holds together skin and bones. 

For staining, he applied the dyes Alcian blue, to highlight 

cartilaginous elements, and alizarin red S, for mineralized tissue. 

Preserving the specimens was accomplished with formalin, 

a clear aqueous solution of formaldehyde and a bit of methanol. 

Then Summers bleached the remaining parts of the fish with hydrogen 

peroxide and immersed it in glycerin. Because glycerin has the same 

index of refraction as collagen, the collagen becomes as clear as water, allowing 

a view through the skin. “It’s a technique I use all the time, but I learn 

different things with every species,” Summers says. 

In this case, he examined the scalyhead sculpin’s armor, which evolved to 

protect it from attack, particularly from above and behind. If that defense 

doesn’t work, Summers notes, the sculpin has a “seriously sharp” preopercular 

spine that points straight out and away when the fish opens its gill coverings. 

The clarified fish may also prove useful to engineers: Its armor may inspire new 

types of protective coverings. —Robert Frederick 


2016 May–June 141 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Cuban and American Physics 

As the political divide between the two countries begins to narrow, 

enthusiasm for scientific collaboration is running high on both sides. 

Just a few weeks ago, a landmark 

meeting of Cubans and Americans 

laid the foundation for a new era 

of cooperation between the two nations. 

No, not Barack Obama’s trip to 

Havana—although the first state visit 

by an American president in more 

than 80 years was certainly newsworthy 

in its own right—but a much 

smaller convocation that went almost 

unnoticed by the press: Several members 

of the Cuban Physical Society 

got together with emissaries from the 

American Physical Society. 

At this gathering, hosted by María 

Sánchez-Colina, president of the Cuban 

Physical Society, the eight physicists 

present traded overviews of their 

organizations and discussed ways of 

deepening their association in the future. 

“The meeting was very friendly, 

and I think it was a first step in gaining 

momentum for exchanges in the 

field of physics between Cuba and the 

United States,” says Ernesto Altshuler, 

professor of physics at the University of 

Havana and editor of the Cuban Journal 

of Physics (opposite page). “One premise 

was clear to all the participants even before 

we began: In spite of the huge differences 

in size between the American 

Physical Society and the Cuban Physical 

Society, we would respect each other 

and collaborate with each other. We 

would respect diversity, so to speak.” 

Such collegial exchanges are not 

unusual for Cuban physicists. For example, 

for decades they have enjoyed 

mutually fruitful scientific exchanges 

with the Abdus Salam International 

Centre for Theoretical Physics (ICTP), 

an organization housed in Trieste, Italy. 

The ICTP has sponsored courses 

and workshops in Cuba, as well as the 

attendance of Cuban scientists at international 

meetings in Italy. 

By contrast, decades of estrangement 

with the United States have left 

their mark, in that many practical 

challenges still clutter the path of free 

scientific exchange. Although travel 

from Cuba to the United States is now 

a fairly straightforward matter, travel 

to Cuba for American citizens is still 

“not trivial,” says Altshuler. He adds, 

however, “Things are now changing 

so fast in that respect that I can hardly 

follow them!” 

The two representatives from the 

American Physical Society—Laura 

At the University of Havana, physics professor Ernesto Altshuler (seated, in plaid shirt) and 

undergraduate students show their sand-flow experiment to visitor Laura Greene, presidentelect 

of the American Physical Society. (Standing, left to right: Leonardo Domínguez, Andy 

S. García, Greene, and Adrián Enrique. Photograph by Gustavo Sánchez.) 

Greene, the society’s president-elect, 

and Amy Flatten, its director of international 

relations—had already planned 

to attend an international workshop on 

science teaching in Havana, so it was 

natural that when they convened with 

colleagues in the Cuban Physical Society 

the talk would turn first to increasing 

the exchange of students, researchers, 

and professors. Cuban physicists 

are eager to host U.S. professors who 

can give seminars and short courses. 

“We’re also having a first look at the 

possibility of future donations of scientific 

equipment—even simple devices 

such as standard digital cameras—to 

Cuba from the States, because since 

the early 1990s, with a lack of support 

from the former Soviet Union and some 

other countries, combined with the embargo, 

our material support was going 

really far down,” Altshuler explains. 

For his part, Altshuler has survived 

as a physicist by devising simple experiments 

from materials that are readily 

available. One creative exercise of his 

faculties led him to study the physical 

principles governing the behavior 

of panicked ants; another (illustrated in 

the box on the facing page) allows him to 

investigate the dynamics of granular 

matter. Although he considers himself 

fortunate to do part of his work in areas 

of physics in which the ability to improvise 

can be fruitful, he worries about 

the sustainability of research in other areas—those 

in which difficult-to-obtain 

equipment (for instance, an electron 

microscope or an x-ray diffractometer) 

may be essential for progress. For many 

years, the embargo has made it difficult—not 

to say impossible—to sell or 

donate to Cuba any scientific equipment 

unless the donating country can stipulate 

that the American-made parts of the 

equipment constitute less than a certain 

percentage of the whole instrument. 

If the embargo has largely prevented 

an influx of the latest scientific equipment 

into Cuban research facilities, 

it has been less successful at the level 

of individual scientists. As far back as 

2000, Altshuler held a postdoctoral position 

at the Texas Center for Superconductivity; 

he visited Argonne National 

Lab and the Rockefeller University last 

February and is planning a similar trip 

early in 2017. And some American scientists 

have come to Cuba: At the University 

of Havana, the physics department 

alone has hosted visits from Leon 

Lederman, Murray Gell-Mann, Walter 

Kohn, and Leo Kadanoff, among 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


others; most recently, Greene gave a 

physics colloquium at the university. A 

workshop on complex matter physics, 

organized in 2012 by Altshuler and his 

Norwegian colleague Jon Otto Fossum, 

brought eminent physicists to Havana 

from 10 different countries, 

including several invited 

speakers from the United 

States. According to Altshuler, 

“There has been an 

exchange, but not at the 

level we have had with Europe 

or Mexico or Brazil.” 

Certain fields, such as medicine 

and the biomedical sciences, 

have seen a higher 

level of exchange in the past 

decade because of important 

mutual interests—in particular, 

the need to confront rapidly 

spreading diseases. 

However, says Altshuler, 

“Now, after the first contacts 

between Obama and Raul 

Castro and others, definitely 

there is a lot of expectation— 

and there are lots of new contacts, 

which have to mature. In my 

own experience, I am receiving two or 

three proposals every month from U.S. 

scientists who want to come to Cuba, 

who want to co-organize a scientific 

meeting in Cuba, and more.” Altshuler 

is inclined to think that at this 

point, so early in the rapprochement 

between the two countries, it may be 

too soon to say how profoundly the 

new political relationship may change 

the research environment across the 

Florida Straits. He does observe, however, 

that “the first derivative of the 

system is very high.” 

A Web Held Together by Knowledge 

When asked to name the greatest asset 

that he and his Cuban colleagues can offer 

new collaborators, Altshuler doesn’t 

hesitate: “The greatest asset is enthusiasm!” 

He is referring not only to his own 

energetic curiosity, but also to the enthusiasm 

he foresees among young researchers 

and students. 

Moreover, physicists in 

Cuba have a highly developed 

ability to get results 

out of small resources. 

For example, Osvaldo 

de Melo and Roberto Cao, 

also at the University of 

Havana, have been creating 

nanostructures for decades 

through the efficient use of 

extremely basic equipment. 

In 2004, when the thawing 

of American–Cuban 

relations was only a distant 

hope, two American Scientist 

editors visited Cuba and 

spoke with a number of scientists 

there. Sergio Pastrana, 

who at that time oversaw international 

relations for the Cuban 

Academy of Sciences, shared his 

vision for the future: “Eventually, Cuba 

could live off knowledge instead of 

sugar.” Twelve years afterward, when 

Altshuler is asked to lay out his own 

vision, he focuses on the effective use 

of Cuba’s human resources: “I would 

say that medical and biotechnological 

services and products have been reasonably 

successful already, in spite of 

the embargo. But I feel that the country 

needs to strengthen the connection between 

industry and other disciplines: 

mathematics, computer science—and 

physics, of course.” Ultimately, Altshuler 

hopes to see Cuba supported by 

“a robust web of resources, in which 

knowledge should be like the glue linking 

all of them.”—Sandra J. Ackerman 

Shaking Grains for Science 

Hele Shaw cell 

a y 

With state-of-the-art scientific equipment 

hard to come by, some physicists in Cuba 

have become adept at building for themselves 

the experimental instruments that they need. 

Shown here is a custom-made device the Altshuler 

lab uses to explore the dynamics of laterally shaken 

granular matter during the intrusion of a solid object 

(pink box). The grains—ion-exchange beads that had 

been thrown away by the chemistry department—are 

confined in a Hele-Shaw cell, which is made to oscillate 

by an electromagnetic shaker that had been set 

aside for disposal before being repurposed. Using 

two wireless accelerometers, one glued to the Hele- 

Shaw cell and the second located inside the intruding 

object, the researchers developed a technique they call 

lock-in accelerometry. A Go-Pro camera, used to double-check 

the penetration of the intruder, oscillates 

relative to the ground, as does the Hele-Shaw cell. 

intruder 

(probe accelerometer inside) 

shaking 

shaking 

camera 

a z 

a x 

reference 

accelerometer 

air injection tubing 

To study the dynamics of granular matter, Altshuler and his research team 

built their own device using a Go-Pro camera, wireless accelerometers, and 

a recycled chemistry electromagnetic shaker. (Photograph by L. Alonso; 

image adapted from Reviews of Scientific Instruments.) 


2016 May–June 143 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


_______ 


2016-05SpotlightCuba.indd 144 


qM 

qM q 

qM q 

M 

M 

Qmags 

4/7/16 THE WORLD’S 8:17 NEWSSTAND AM ®



qM 

qM q 

qM q 

M 

M 

Qmags 


Briefings 

In this roundup, digital features 

editor Katie L. Burke summarizes 

notable recent developments in scientific 

research, selected from reports 

compiled in the free electronic newsletter 

Sigma Xi SmartBrief. Online: https:// ____ 

www.smartbrief.com/sigmaxi/index.jsp 

Gravitational Waves Detected 

Predicted by Albert Einstein 100 years 

ago, ripples in space-time called gravitational 

waves have been directly observed 

for the first time at the Laser Interferometer 

Gravitational-Wave Observatory 

(LIGO). This 

discovery confirms 

Einstein’s 

general theory 

of relativity, 

and hence the 

existence of 

black holes; 

T. Pyle/Caltech/MIT/LIGO Lab 

it also opens 

new territory for studying collapsed stellar 

remnants and extreme gravitational 

phenomena. According to the theory, 

two black holes orbiting one another 

gradually spiral inward until they collide. 

During that event, they merge, 

converting a sizable portion of their mass 

to energy emitted as a surge of gravitational 

waves. LIGO physicists detected 

such a surge from a pair of black holes, 

29 and 36 times as big as the Sun, 1.3 

billion light years away. The resulting 

gravitational ripples distorted LIGO’s twin 

detectors by only 1/1,000th the diameter 

of a proton—but that was enough for a 

definitive detection. Physicists are now 

working to improve existing gravitational 

wave detectors and to add new ones. 

Abbott, B. P., et al. Observation of gravitational 

waves from a binary black hole merger. Physical 

Review Letters 116:061102 (February 11) 

Oldest Fossil Nervous System 

A 520-million-year-old fossil of an early 

ancestor of arthropods contains remarkably 

preserved nerves. Found in southern 

China, the animal, named Chengjiangocaris 

kunmingensis, dates to the Cambrian 

explosion, during which many modern 

animal lineages emerged. It belongs 

to a group of animals called fuxianhuiids 

that share ancestry with insects, spiders, 

and crustaceans. Partially fossilized nervous 

systems have been found in other 

species from the same period, but they 

mostly have preserved only the profile of 

the brain. This fossil shows a nerve cord 

running down the length of its body, 

with beadlike ganglia controlling each of 

its many pairs of legs. The ganglia have 

tiny spindly fibers, individual nerves that 

fossilized as carbon films. Its nervous 

system is similar to that of modern-day 

velvet worms, but modern arthropods 

have evolved a simpler nervous system. 

The fossil's nerve cord also has a unique 

structure unknown in extant organisms. 

Yang, J., et al. Fuxianhuiid ventral nerve 

cord and early nervous system evolution 

in Panarthropoda. Proceedings of the National 

Academy of Sciences of the U.S.A. 

113:2988–2993 (March 15) 

Earth’s Rarest Minerals 

A study reviews Earth’s rarest minerals— 

those found at five or fewer locations on 

the planet. Researchers divided the 2,500 

rare minerals that they identified into 

four categories that relate to the conditions 

under which they form, how rare 

their ingredients are, how stable they 

are, and whether they come from poorly 

studied locations. The resulting catalog 

Robert Downs, University of Arizona 

will assist in determining where and how 

large certain rare minerals’ reserves may 

be; it also will help geophysicists study 

the fundamental construction of Earth. 

Hazen, R. M., and J. H. Ausubel. On the 

nature and significance of rarity in mineralogy. 

American Mineralogist doi: 10.2138/ 

am-2016-5601CCBY (in press) 

Fast Radio Bursts Controversy 

A paper claiming to trace fast radio bursts, 

mysterious fleeting radio waves from outer 

space, to their source has sparked a hot 

controversy among astronomers. These 

bursts last milliseconds but may contain as 

much energy as the Sun would emit in a 

year. The first fast radio burst ever detected 

hit a dish in 2001 but was not reported 

until 2007, so a big hurdle to finding their 

source has been closing this lag time; the 

bursts are also rare, with just 17 observed. 

Researchers led by Evan Keane set up an 

alert system triggered when live data suggest 

a fast radio burst is happening. After 

an alert, his team said they observed the 

burst's afterglow and zoomed in on the 

source. They pinpointed the burst to an 

elliptical galaxy 6 billion light years away. 

However, 

Harvard astronomers 

Peter Williams 

and 

Edo Berger 

say that the 

radio signal 

attributed to 

CSIRO/Alex Cherney 

the afterglow 

is actually from an unrelated supermassive 

black hole. The source of fast radio bursts 

continues to be debated. Some bursts 

seem to repeat—which would not happen 

in the case of a one-time event like 

colliding stars. 

Keane, E. F., et al. The host galaxy of a fast radio 

burst. Nature 530:453–456 (February 25) 

Williams, P. K. G., and E. Berger. No precise 

location for FRB 150418: Claimed radio 

transient is AGN variability. http://arxiv.org/ 

abs/1602.08434v3 (March 25) 

___________ 

Microcephaly Risk with Zika 

An epidemic of the mosquito-borne Zika 

virus has been spreading in the Americas, 

coinciding with an increase in babies 

born with abnormally small heads, or microcephaly, 

and associated neurological 

birth defects. Drawing on records from a 

2013–2014 epidemic in French Polynesia, 

researchers confirmed the link between 

Zika and microcephaly and calculated the 

risk for infected pregnant women. Their 

model shows that risk of a fetus with 

microcephaly increases from the norm 

of 0.02 percent to 1 percent for mothers 

infected with Zika during the first trimester 

of pregnancy. Although this level of 

risk is much lower than the risk of complications 

during pregnancy caused by 

other viral infections, such as rubella, it is 

still cause for concern because in affected 

areas the proportion of a population 

infected with Zika can exceed 50 percent. 

Researchers are attempting to isolate the 

mechanism that causes the birth defects. 

Cauchemez, S., et al. Association between 

Zika virus and microcephaly in French Polynesia, 

2013–15: a retrospective study. Lancet 

doi:10.1016/S0140-6736(16)00651-6 

(March 15) 


2016 May–June 145 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Perspective 

The Imprecise Search for 

Extraterrestrial Habitability 

How can scientists hunt for alien habitats without defining life? 

Kevin Heng 

As planets are being discovered 

around other stars by 

the thousands, several scientific 

disciplines, including 

astronomy, planetary science, and biochemistry, 

are converging, with the goal 

of locating and identifying life elsewhere 

in the Universe. We are engaged 

in a search for habitability—conditions 

suitable for life—even though we lack 

a clear definition of what life is. We 

are hunting for something we cannot 

yet sharply define. Nevertheless, we 

can make informed inferences about 

what life requires. From what we know 

about life on Earth, liquid water appears 

to be an essential ingredient. If 

an exoplanet orbits at the appropriate 

range of distances from its star to allow 

liquid water to exist on its surface, then 

it is said to be in the habitable zone—it is 

not too hot, not too cold, purportedly 

just right for living things. 

The notion of the habitable zone 

has its origins in what we know about 

the planetary trio of Venus, Earth, and 

Mars. With surface temperatures exceeding 

400 degrees Celsius, presentday 

Venus is a scorching inferno largely 

devoid of water. Its hostile temperatures 

are a direct consequence of its thick atmosphere 

being dominated by carbon 

dioxide—a powerful greenhouse gas 

that makes up less than one part in a 

thousand of the atmosphere of Earth. 

Kevin Heng is a professor of astronomy and planetary 

science and director of the Center for Space and Habitability 

at the University of Bern, Switzerland. He is 

also a subproject leader of the Swiss PlanetS National 

Center for Competence in Research and a core science 

team member of the Swiss-led CHEOPS mission to 

hunt for Earth-like exoplanets around nearby stars. 

Twitter: @KevinHeng1. 

Mars is a study in contrasts, having a 

thin atmosphere, large temperature 

swings, and an average surface temperature 

that is well below the freezing 

point of water. Earth sits between these 

two extremes, so it is convenient to visualize 

Earth as residing within a zone of 

habitability, flanked by Venus and Mars. 

With the flurry of recent discoveries 

made with the Kepler Space Telescope, 

it is routine to encounter media reports 

of “habitable-zone exoplanets”— 

sometimes accompanied by speculation 

on what types of life forms may 

exist on them—using a conception of 

the habitable zone that extrapolates 

directly from what we know about 

our own Solar System. The habitable 

zone is a star-specific concept, however. 

Stars exist in a variety of sizes 

and masses. More massive stars tend 

to burn more brightly but have shorter 

lifetimes. The most common types of 

stars in the Universe are not like our 

Sun, but instead have masses between 

10 and 50 percent of it. These red dwarfs 

have cooler temperatures than our 

Sun and radiate far less energy, which 

means that if a planet of Earth’s size 

were to maintain the same range of atmospheric 

temperatures it would have 

to orbit such stars more closely. 

A Problem of the Atmosphere 

The habitable zone is also an 

atmosphere-specific concept. Three 

types of atmospheric gases strongly influence 

a body’s surface temperature. 

First, we need an incondensible greenhouse 

gas—one that stays in its gaseous 

form over the range of temperatures 

found in the atmosphere. On Earth, this 

role is played by carbon dioxide. Second, 

we need a condensible greenhouse 

gas, which exists in both gaseous and 

liquid forms. Water is the condensible 

greenhouse gas of our atmosphere and 

is the lynchpin of the hydrological cycle. 

The boundaries of the habitable zone 

are determined by what happens to the 

condensible and incondensible greenhouse 

gases at different distances from 

the parent star. The inner boundary 

of the habitable zone is the distance 

at which the condensible greenhouse 

gas cannot condense, and the outer 

boundary of the habitable zone is the 

distance at which the incondensible 

greenhouse gas can condense. If the 

Earth were located too close to the Sun, 

then higher temperatures would result 

in more water existing as vapor, which 

in turn would lead to further warming. 

The planet would compensate for this 

greenhouse warming by emitting more 

infrared radiation and by shedding 

heat, but at some point there would 

be so much water vapor in the atmosphere 

that it would become opaque 

to infrared radiation. At that point, the 

cooling of the atmosphere would be 

overwhelmed by heating, leading to a 

runaway greenhouse effect. Venus is 

believed to have suffered this fate. 

The third ingredient needed is an 

inert gas, and its role is subtle. On 

Earth, the primary inert gas is molecular 

nitrogen. It does not contribute to 

greenhouse warming, because a nitrogen 

molecule has an even distribution 

of electric charge across it. Quantum 

physics tells us that such molecules are 

largely incapable of absorbing radiation. 

Counterintuitively, despite being 

the dominant gas by mass, molecular 

nitrogen is transparent to the radiation 

received and emitted by Earth. However, 

as the atmosphere warms and 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Don Dixon 

This rendering of early Earth shows a volcano building the planet’s atmosphere over an ocean that does not yet harbor life. The distance 

from a star at which water can exist in liquid form on a planet’s surface is an important element of astronomers’ current definition of the 

habitable zone. But are astronomers asking the right questions about habitability? 

accumulates water vapor, water and 

nitrogen molecules collide. Absorption 

of units of light or radiation, known as 

photons, must match the discrete energy 

levels within a water molecule. When 

water and nitrogen molecules collide, 

deficits or surpluses of energy are exchanged. 

Known as pressure broadening, 

this effect increases the extent to 

which the water molecules may absorb 

radiation. Molecular nitrogen does not 

directly absorb light, but it influences 

how the greenhouse gases do so. 

Inert gases also set a characteristic 

distance in the atmosphere known as 

the pressure scale height, which determines 

whether an atmosphere is puffy 

or compact. Hydrogen-dominated atmospheres 

tend to be puffier than their 

nitrogen-dominated counterparts. Furthermore, 

inert gases may participate 

in the chemistry involving greenhouse 

gases and can alter their abundances. 

If we were to move Earth farther 

from the Sun, then at some point carbon 

dioxide would condense out of its 

atmosphere. As this greenhouse gas 

was removed, the atmosphere would 

cool and the overall temperature 

would drop. The outer boundary of the 

habitable zone is the distance from the 

Sun at which the atmosphere becomes 

too cool to support liquid water on the 

surface of the body. At high pressures, 

nitrogen molecules may form transient 

pairs, which have an uneven distribution 

of electric charge across them. 

These pairs produce a weak greenhouse 

effect known as collision-induced 

absorption. One imagines that the loss 

of gaseous carbon dioxide may be compensated 

for by packing more molecular 

nitrogen into the atmosphere, but 

there is a limit to the mileage gained, 

because the nitrogen also condenses 

out, at some point, when the temperature 

becomes too low. 

Once we understand how greenhouse 

gases control the habitable-zone 

boundaries, we may imagine different 

flavors of habitable zones. Molecular 

nitrogen may be swapped out for molecular 

hydrogen, which has a considerably 

lower condensation temperature: 

tens of kelvin, rather than about a hundred. 

For planets with hydrogen-rich 

atmospheres, the outer boundary of 

the habitable zone may extend several 

times as far from the star, because molecular 

hydrogen compensates for the 

loss of the incondensible greenhouse 

gas through collision-induced absorption, 

thereby warding off its condensation. 

Water and carbon dioxide may be 

exchanged for other greenhouse gases, 

which could absorb and reradiate heat 

at other wavelengths or frequencies. 

Generally, a greenhouse gas is effective 

only if it is absorbent at wavelengths 

over which the planet is emitting radiation. 

A greenhouse gas that favors the 

absorption of blue light is useless if the 

planet emits only red light. 

A fascinating example of a place 

with alternative atmospheric chemistry 

is found on Titan, a moon of Saturn 

that is about 40 percent of the size of 

Earth and has a fully functioning atmosphere. 

As in Earth’s atmosphere, 

the inert gas is molecular nitrogen, and 

methane is a greenhouse gas. But unlike 

on Earth, where methane exists 

only in gaseous form, it is a condensible 

greenhouse gas on Titan because of 

the considerably lower temperatures. 

Instead of carbon dioxide, the incondensible 

greenhouse gas is molecular 

hydrogen, which plays a negligible 

role on Earth. Molecular hydrogen 

warms the atmosphere of Titan via 

collision-induced absorption. Titan is 

hardly in the habitable zone for liquid 

water, but it would be in the habitable 

zone for liquid methane! 

Without knowledge of the major 

molecules of an exoplanet’s atmo- 


2016 May–June 147 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


stellar temperature (Kelvin) 

7,000 

6,000 

5,000 

4,000 

3,000 

hot zone warm “habitable” zone cold zone 

Venus 

Earth 

Mars 

too hot for 

liquid water 

carbon dioxide 

can condense 

to liquid 

0 1 2 3 4 

planet’s distance from its star (Earth–Sun distance = 1) 

The habitable zone of an exoplanet 

is the range of distances from a star 

at which liquid water may exist 

on the surface of the exoplanet. In 

this schematic, it is assumed that 

the atmosphere of the exoplanet 

has exactly the same amounts of 

nitrogen, oxygen, carbon dioxide, 

and water as Earth. Habitability on 

an exoplanet’s surface requires an 

atmosphere with an incondensible 

greenhouse gas, such as carbon dioxide, 

that stays gaseous over the 

range of temperatures found there, 

and a condensible greenhouse gas, 

such as water vapor, that exists as 

a gas and a liquid. Changing the 

relative amounts of these gases 

causes the boundaries of the habitable 

zone to shift. The smaller and 

cooler the star, the closer its habitable 

zone will be. 

sphere, we can only speculate whether 

it resides in the habitable zone for liquid 

water. It is akin to assuming that 

the exoplanet has an atmosphere exactly 

like Earth’s, consisting of nitrogen, 

water, and carbon dioxide—in 

precisely the same relative amounts, 

summing up to exactly the same total 

mass. Declaring a freshly detected 

exoplanet to be in the “habitable zone” 

amounts to little more than media spin 

if its atmospheric composition is unknown. 

Even professional astronomers 

sometimes forget this fact. 

One of the most promising worlds 

in which to search for life in our Solar 

System illustrates why the habitable 

zone concept may be incomplete. Europa, 

one of Jupiter’s moons, sits outside 

of the traditional habitable zone. 

It has no atmosphere, and water is not 

liquid at its surface. However, a body 

of evidence suggests that a deep ocean 

exists beneath its icy surface, which 

may host life. Unfortunately, even if 

subsurface habitats for life are common 

on exoplanets, they are currently 

invisible to astronomers. 

Thinking Outside the Zone 

Current technology largely restricts us 

to characterizing the atmospheres of 

exoplanets that are Jupiter-like in size. 

As technology advances, astronomers 

expect to decipher the atmospheres 

of smaller, Earth-like exoplanets. Can 

we predict what the compositions of 

these atmospheres are in advance? 

Unfortunately, this task is daunting 

for smaller exoplanets. We expect the 

gas-giant exoplanets to have volatile 

elements (ones that vaporize at modest 

temperatures) in a mix that bears 

Europa 

Titan 

Venus 

Earth 

The planets Venus and Earth and the moons Titan and Europa help illustrate the difficulty of defining habitability. Earth serves as our one 

known example of a habitable planet. On Venus, high levels of carbon dioxide in its thick atmosphere are thought to have caused runaway 

greenhouse warming that ultimately made the planet inhospitable to life. Saturn’s moon Titan, which sits outside the habitable zone for liquid 

water, could sit in a zone of habitability defined by liquid methane. Jupiter’s moon Europa also sits outside the conventional habitable 

zone. It has no atmosphere and no liquid water on its surface. But evidence suggests that it has a deep subsurface ocean that could harbor life. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


NASA 

some semblance to those of their parent 

stars. For exoplanets dominated by 

a rocky core, we expect their refractory 

elements (ones that remain solid), but 

not the volatile ones, to mirror those of 

the star. In other words, we expect the 

rocks of the exoplanet, but not its gas, 

to mirror the metals in the star. 

This expectation is certainly met 

by Earth, whose nitrogen-dominated 

atmosphere hardly resembles the 

hydrogen-dominated Sun. On Earth, 

the amount of carbon dioxide present 

in the atmosphere is regulated by the 

inorganic carbon cycle, which operates 

on geological time scales of hundreds 

of thousands of years. Through the 

process of weathering, gaseous carbon 

dioxide reacts with silicate rocks and 

water to form calcium carbonate, which 

is then subducted into Earth’s mantle. 

This part of the cycle acts as a carbon 

sink. Carbon dioxide is released back 

into the atmosphere via outgassing and 

volcanic activity. The inorganic carbon 

cycle acts like a geochemical thermostat: 

Weathering is more active when 

the conditions are wetter and warmer, 

which regulates the amount of carbon 

dioxide present (although not on short 

enough timescales to mitigate humaninduced 

climate change). And when the 

Earth is in a frozen, ice-covered state, 

weathering is shut off. Outgassing continues 

to increase the amount of carbon 

dioxide in the atmosphere of this snowball 

Earth, until greenhouse warming 

suffices to melt the ice and snow. 

The existence of the inorganic carbon 

cycle on Earth suggests that to 

understand the atmospheres of rocky 

exoplanets we need to understand the 

geochemistry of their surfaces. Is water 

always the solvent? Are the minerals 

and rocks the same as those on Earth? 

Is carbon dioxide the only greenhouse 

gas being geochemically regulated? Are 

these long-term geochemical cycles necessary 

for stable, habitable climates? 

Until we resolve these puzzles, our theories 

will have little predictive power. 

That said, nature offers hints that life 

elsewhere in the Universe, if it exists, 

may not be that different from life on 

Earth. Science fiction has popularized 

the idea of silicon-based life, since silicon 

resides in the same group as carbon 

in the periodic table. This analogy 

breaks down when one examines the 

details, however. The chemical bond of 

silicon dioxide is too strong, while the 

silicon–silicon bond is too weak. Silicon 

dioxide (quartz) is an overly stable 

sink of silicon and is insoluble in water. 

These properties prevent silicon from 

forming a variety of complex molecules 

as carbon does. This expectation 

is consistent with what astronomers 

find when pointing their telescopes at 

seemingly uninteresting parts of space: 

an abundance of organic molecules, 

ranging from methanol and glycine (an 

amino acid) to fullerene (the “buckyball” 

with 60 carbon atoms). The 

building blocks of life, as we understand 

them on Earth, are commonly 

found elsewhere in the cosmos— 

preassembled. Darwin’s “warm little 

pond” idea of organic molecules forming 

in a primeval soup on Earth may 

need rethinking. 

In the future, as astronomers detect 

molecules in the atmospheres of Earthlike 

exoplanets, the challenge will lie in 

interpretation of the data. What combinations 

of molecules need to be present 

for us to declare that extraterrestrial 

life has been detected? Classic ideas 

We are hunting for 

something we cannot 

yet sharply define. 

include the presence of oxygen and 

ozone. A potential false positive is the 

abiotic production of oxygen and ozone 

via the photolysis of water—the breakup 

of water molecules when they are 

exposed to ultraviolet radiation from 

the star. On Earth, water resides close 

to its surface, rendering such a process 

ineffective. The laws of physics, as we 

understand them, suggest that such a 

cold trap may not be operational on all 

exoplanets, implying that the detection 

of oxygen and ozone alone cannot be 

robust indicators of life. (We may potentially 

distinguish this scenario by 

measuring the escape of hydrogen from 

the exoplanet.) We need to understand 

what we should additionally look for. 

Indicators of Life 

Another consideration in the search 

for life on exoplanets is that our candidates 

for biosignature gases are based 

on the atmosphere of Earth and on 

metabolic cycles as we understand 

them. It is conceivable that some fraction 

of rocky exoplanets instead have 

thin, hydrogen-dominated (rather than 

nitrogen-dominated) atmospheres. In 

such atmospheres, atomic hydrogen 

acts as a radical (a reactive state in 

which some electrons are left unpaired) 

and destroys most of the molecules we 

regard as indicators of life. Ammonia 

and nitrous oxide are the most promising 

candidates for biosignature gases 

in such environments, because they 

are spared destruction by hydrogen. 

Methane and hydrogen sulfide, which 

are produced by life on Earth, become 

unreliable indicators, because they 

may be produced abiotically via geochemistry. 

Clearly, whether a specific 

molecule can be interpreted as a biosignature 

gas depends on the type of 

atmosphere the exoplanet has. 

Generally, the difficulty with making 

the leap from the detection of molecules 

in an exoplanetary atmosphere to the 

identification of life is that many of the 

gases emitted by life are also manufactured 

by geology. The challenge may be 

framed as the identification of true biosignature 

gases in the face of geological 

false positives. Familiar gases such as 

ammonia, carbon dioxide, methane, oxygen, 

and water vapor are not uniquely 

associated with life. Exotic ones, such as 

dimethylsulfide, may potentially serve 

as biosignature gases, but they are difficult 

to detect in the spectrum of an 

exoplanetary atmosphere because their 

spectral signatures are subtle. 

Ultimately, the search for life elsewhere 

in the Universe may require that 

we be able to define what life actually 

is. There is a lesson from earlier periods 

of human history—for instance, water 

was once described by its properties, 

rather than by its stoichiometry, due 

to our ignorance (then) of chemistry. 

We are facing the same struggle with 

the definition of life, because of our 

current inability to frame biology in 

sufficiently precise terms. Astronomers 

will continue to improve and sharpen 

their search for life elsewhere, while 

awaiting a general definition of life—a 

task best left to the biologists, but one 

with vast cosmic implications. 

Bibliography 

Kasting, J. 2010. How to Find a Habitable Planet. 

Princeton: Princeton University Press. 

Pierrehumbert, R., and E. Gaidos. 2011. Hydrogen 

greenhouse planets beyond the habitable 

zone. Astrophysical Journal Letters 734:L13. 

Seager, S., W. Bains, and R. Hu. 2013. Biosignature 

gases in H 2 -dominated atmospheres on 

rocky exoplanets. Astrophysical Journal 777:95. 

Wordsworth, R., and R. Pierrehumbert. 2014. 

Abiotic oxygen-dominated atmospheres on 

terrestrial habitable zone planets. Astrophysical 

Journal Letters 785:L20. 


2016 May–June 149 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Engineering 

Traffic Signals, Dilemma Zones, 

and Red-Light Cameras 

After almost a century of study, engineers are still debating the best ways 

to help drivers move as safely and efficiently as possible. 

Henry Petroski 

Traffic congestion did not begin 

with the automobile. Just 

before the turn of the 20th century, 

when horses and wagons 

alone filled the streets of cities, gridlock 

was already common in large urban 

centers. Policemen assigned to traffic 

duty at an intersection were ill prepared 

to singlehandedly deal with the 

growing volume of horse-drawn vehicles 

wishing to pass through it. And 

untangling a logjam of carriages when 

the opera let out was a Herculean task. 

The advent of the automobile only 

exacerbated the problem. As late as 

1911 there were few traffic control 

devices in the form of signs or signals 

to help: In a contemporary book 

of photographs documenting New 

York’s Fifth Avenue block by block, 

from Washington Square Park to East 

Ninety-Third Street, there was not a 

traffic control device to be seen. Soon 

rudimentary ones began to be invented, 

however, and they proliferated in 

cities across the nation. 

Many of the earliest traffic signals 

resembled railroad semaphores, with 

arms labeled STOP and GO, sometimes 

illuminated for nighttime use. 

The signal pole was often planted in 

the middle of an intersection and operated 

manually by a policeman standing 

beside it on the street or in a crow’s 

nest atop a tower. In 1912 in Salt Lake 

City, Utah, Officer Lester F. Wire felt 

Henry Petroski is the Aleksandar S. Vesic Professor 

of Civil Engineering and a professor of history 

at Duke. His most recently published book is 

The Road Taken: The History and Future of 

America’s Infrastructure (Bloomsbury, 2016). 

Address: P.O. Box 90287, Durham, NC 27708. 

unsecure standing among the traffic he 

was responsible for directing at a busy 

downtown intersection. Determined 

to make his job safer and easier, he reportedly 

used plywood to build a device 

that looked somewhat like a birdhouse 

for large birds. It had a couple of 

15-centimeter-diameter holes on each 

of the signaling faces. In each of these 

holes was a light bulb that had been 

dipped in either red or green paint. By 

means of a manual switch, the lights 

could be illuminated to signal oncoming 

traffic to stop or go. The entire signal 

was painted yellow to enhance its 

visibility. The Salt Lake City device is 

generally regarded as the first traffic 

light in the United States. Cleveland 

was another early adopter, having a 

traffic light permanently installed as 

early as 1914. 

Manually controlled traffic signals 

were only a partial solution, however. 

They still had to be attended by 

a policeman, who not only changed 

the lights from green to red to stop 

main-street traffic but also waved on 

cross-street traffic, for which there was 

no light. When the cross traffic had 

cleared the intersection, the officer 

switched the light back to green. Traffic 

signals controlling both the main 

and cross streets were an obvious improvement, 

but the earliest ones were 

not standardized with regard to the 

position of the red and green lights 

because a single bulb was used to illuminate 

all four faces of each signal 

box. If two opposing faces were fitted 

with red lenses, then the other two 

at the same level would have to be 

fitted with green ones. This arrangement 

meant that the vertical order of 

the lights would vary for the different 

intersecting streets, which presented 

a problem for the 10 percent of male 

drivers who are color blind. 

Lack of standardization was not the 

only shortcoming of early traffic signals. 

In cities such as New York, where 

north-south avenues were considerably 

wider than east-west crosstown 

streets, it took some time to figure 

out the best place to locate signals for 

maximum visibility and effectiveness. 

The city first tried mounting signals 

on towers at Fifth Avenue at Fifty- 

Seventh Street in 1917; a few years 

later several more were put in place 

at other Fifth Avenue intersections. 

Policemen stationed in nearby towers 

visually coordinated the signals. Before 

the traffic lights were installed, the 

2-kilometer drive from Thirty-Fourth 

to Fifty-Ninth Street took almost 45 

minutes; with the towers in place, the 

driving time was reduced to less than 

10 minutes. However, such utilitarian 

signal towers were not considered appropriate 

for the neighborhood. 

All in the Timing 

To replace the unsightly towers with 

more fitting ones, the Fifth Avenue 

Association—an organization that took 

an active interest in preserving the 

character of the famed street and its 

environs—sponsored a national design 

competition for a more attractive trafficsignal 

tower. Of 130 entries, the association 

chose one from New York architect 

Joseph H. Freedlander. His 7-meter-tall 

art-deco structure with neoclassical ornamentation 

was made of cast bronze 

over a steel frame. It sat on a 1.5-metersquare 

concrete base surrounded by a 

Science & Society Picture Library, UDOT, www.trafficsignalmuseum.com, Wikimedia Commons, Photobucket, Matt Weber, ManMadeByDarrellYoung/Alamy, Wikimedia Commons 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Approaches to traffic control have evolved over time. Top row, left to 

right: Schematic for the first traffic light, installed in London (1868); 

Lester Wire’s “birdhouse” signal (1912); William Potts’s three-section 

traffic light (1923); a cross-shaped signal patented by Garrett Morgan 

(1923). Bottom row: traffic light tower in midtown Manhattan, designed 

by Joseph H. Freedlander (1922); Freedlander’s bronze two-color 

signal (1930); four-way traffic lights were ubiquitous by the 1960s; LED 

lights, introduced in the 1990s, are brighter and more efficient. 

traffic island. The entire structure was 

located in the middle of Fifth Avenue, 

offset from the cross street. Such towers 

did not interfere with traffic on the narrow 

crosstown streets, but to increasingly 

heavy Fifth Avenue traffic they 

proved to be intolerable obstructions. 

As attractive as the towers were, the 

association had them removed in 1929 

and asked Freedlander to design a simple 

lightpost that could be installed on 

a sidewalk corner. 

The streamlined bronze signal that 

Freedlander produced was topped 

by a half-meter-tall gold-leafed figure 

of Mercury, the Roman god of merchants 

or, under the name of Hermes, 

the fleet-footed messenger to the Greek 

gods. These attractive traffic signals, 

which remained in service for decades, 

were unusual by today’s standards because 

they had only two lights: red and 

green. New York had outlawed the intermediate 

yellow light because drivers 

had taken its blinking announcement 

of an impending change from red to 

green as license to proceed across an 

intersection prematurely, before the 

cross traffic had cleared the intersection. 

That was a recipe for collision. 

Although a joint board of federal 

and state highway officials had agreed 

in 1925 on the standard red-yellowgreen, 

top-to-bottom arrangement so 

familiar today, it was not until 1928 

that three-colored traffic signals were 

routinely fitted with enough separate 

bulbs so that the red light could appear 

at the top on all four faces. Even 

then not everyone was pleased with 

this sensible organization. In the Irishimmigrant 

district of Tipperary Hill in 

Syracuse, New York, it was considered 

unacceptable to have the British red 

above the Irish green. For years, the 

community prevailed in having the 

traffic lights in its neighborhood display 

the green on top on all four sides. 

By the mid-1920s, cities were 

adopting automatically timed traffic 

lights with startling speed. New York, 

which had 98 lights throughout the 

city in 1926, added 1,143 in 1927, and 

another 2,243 in 1928. Although the 

cost of installation was significant, the 

traffic lights enabled the city to reduce 

the number of police officers on the 

traffic squad from 6,000 to 500, resulting 

in an annual savings of $12.5 million. 

With growing numbers of automated 

traffic signals, cities needed to 

devise a system of coordinating them. 

The simplest way was the so-called 

block system, whereby all lights along 

an avenue are simultaneously either 

red or green. 

William Phelps Eno, an American 

businessman whom the New York Times 

identified as “one of the earliest students 

of traffic conditions,” considered 

this approach wasteful of the street’s 

capacity, since virtually all vehicles using 

the street would be stopped for the 

duration of the red. The other extreme, 

a staggered-red system, allows traffic to 


2016 May–June 151 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


SPEED 

LIMIT 

45 

5.0 

second 

yellow 

light 

+ = 330 feet 

330 feet 

Duration of the yellow light determines how much time a driver has to stop, or to clear the intersection; 

driving speed, reaction times, and road curves and inclinations affect the optimal yellowlight 

interval. Some municipalities that introduced red-light cameras have been accused of shortening 

the yellow-light interval—a procedure that may reduce safety to increase ticket revenue. 

move constantly at a specified speed, 

with the lights turning green just as the 

vehicles reach each intersection. This 

approach can work beautifully, but 

only for a one-way street. 

In time, New York City came around 

to appreciating the value of the yellow 

(or amber) traffic light, whose illumination 

evolved to mean that the greenlight 

period was about to end, warning 

drivers to stop before reaching the intersection 

or to clear it quickly. One of my 

neighbors describes drivers racing into 

the intersection while the yellow is lit as 

“squeezing the lemon.” But the squishy 

question faced by traffic engineers is 

how long the yellow should remain illuminated 

before the cross traffic gets the 

green light. This seemingly simple question 

has been the subject of discussion 

among traffic engineers for almost as 

long as the three-colored traffic light has 

existed, and even today some observers 

feel that it is still not a settled matter. 

Resolving the “Dilemma Zone” 

Attempts to calculate rationally how 

long the yellow light should be illuminated 

date from as early as the late 

1920s, when it was equated with the 

time it took a vehicle to drive at constant 

speed across the width of the intersection. 

This first crude approximation 

did not take into account a driver’s 

response time to a changing signal or 

to the length of the vehicle, nor did it 

allow for the situation in which the 

vehicle was not yet at the intersection 

and its driver had to decide whether 

to stop or squeeze the lemon. These 

factors were incorporated into improved 

formulas contained in successive 

editions of the traffic-engineering 

handbook published by the Institute of 

Traffic Engineers (ITE, now the Institute 

of Transportation Engineers). 

The commonly used formula for the 

minimum time the yellow light should 

be illuminated (often designated Y by 

traffic engineers) follows from equations 

expressing the kinematics of rectilinear 

motion with constant acceleration. 

In its most simple form, it is given 

by Y = t p + v / 2a, where t p is the time 

it takes a driver to perceive the start of 

the yellow interval and react to it by 

hitting the brakes (about 1 second); the 

approach speed v is usually taken to 

be the speed limit (in feet per second, 

or fps) on the road in question, but it 

is also sometimes taken to be the 85 th 

percentile speed of vehicles observed 

using the road; and the assumed uniform 

(constant) deceleration a is the 

rate at which the car is slowing down, 

typically taken as 10 feet per second 

per second (fps 2 ), which is equivalent 

to about 0.3g, or 30 percent of the acceleration 

due to gravity. If a vehicle of 

length L is to be given enough time to 

clear the cross street of effective width 

w, then the term (w + L)/v must be added 

to the right side of the equation. 

Treating the problem as one in operations 

research was first done at the 

General Motors Research Laboratories 

in Warren, Michigan, by a trio led by 

Denos Gazis, who published their results 

in 1960. Employing kinematic 

equations giving distance traveled 

from the onset of the yellow light, and 

assuming there is a maximum deceleration 

a max greater than which a vehicle 

cannot achieve, the researchers determined 

that there is a critical distance 

from the intersection beyond which 

stopping before entering the intersection 

is not an option. 

The GM researchers also calculated 

the so-called maximum-clear distance 

that the driver can be from the intersection 

when the yellow light first appears 

and still be able to clear the intersection 

without accelerating. If the 

car is closer to the intersection than the 

critical distance but greater than the 

maximum-clear distance away, then 

the driver cannot stop safely before 

reaching the intersection and so must 

try to accelerate to clear it, which could 

involve going over the speed limit. In 

this case the driver is said to be in the 

“dilemma zone.” 

According to the latest (2009) edition 

of the Manual on Uniform Traffic 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Wikimedia Commons 

Control Devices, which serves as the 

national standard, “the duration of the 

yellow change interval shall be determined 

using engineering practices,” 

which include employing professional 

engineering judgment about whether 

or not to use the formulas described 

above. However, the standard also offers 

as guidance that the yellow-light 

interval should fall between 3 and 6 

seconds. Because not all traffic necessarily 

clears the intersection at the end 

of the yellow, cross traffic is not expected 

to be shown a green signal until 

after a red clearance interval, during 

which all directions of traffic see a red 

light. The duration of this clearance 

interval is also determined by means 

of engineering practices. 

The leeway given to traffic engineers 

in setting the yellow and all-red 

intervals allows them to take into account 

the idiosyncrasies of individual 

intersections, such as visibly obstructed 

signals. But engineers also 

warn that making the yellow interval 

too long (say, greater than 5 seconds) 

“may lead to loss of drivers’ respect 

for the yellow light.” To keep this from 

happening, they suggest that some 

proportion of a longish calculated yellow 

interval be incorporated into the 

all-red interval that follows. Further 

complicating the yellow interval determination 

is the fact that some traffic 

jurisdictions allow vehicles to enter 

the intersection as long as the yellow 

light is illuminated (the “permissive 

yellow rule”), whereas others demand 

that the intersection be cleared completely 

before the red light appears. 

The change interval has been described 

as the most important aspect 

of safe signal timing, and as early as 

1983 it was considered to be among 

the most controversial decisions a traffic 

engineer could make. A decade 

later there was still no consensus on 

the matter of the yellow interval, and 

a technical council of the ITE prepared 

an informational report presenting 

a variety of approaches rather than 

a definitive recommended practice. 

Among the observations in the report 

was that the familiar formula for the 

change interval might not apply when 

left turns are involved, largely because 

the speed at which turns are made can 

depart greatly from that typically used 

in the formula. Furthermore, because 

a turning vehicle’s acceleration will 

not be uniform, the kinematic formula 

does not exactly apply. A 2012 report 

from the Transportation Research 

Board—a division of the National Research 

Council of the National Academies 

of Sciences, Engineering, and 

Medicine—began by reminding readers 

that “for over 70 years, the subject 

of yellow and red signal indications 

has been a popular topic among scholars 

and professionals in the traffic engineering 

field.” 

Controversial Cameras 

In recent years some communities 

have installed red-light cameras, in addition 

to traffic signals, at intersections. 

When a vehicle enters the intersection 

after the yellow light has changed to 

red, the cameras capture an image of 

the license plate of an offending vehicle, 

and a citation is automatically 

issued to the registered owner. 

Making the yellow 

interval too long (say, 

greater than 5 seconds) 

“may lead to loss of 

drivers’ respect for 

the yellow light.” 

Chicago once had the nation’s largest 

automated ticketing program; at its 

peak more than 380 such cameras were 

installed and operated by the Australian 

firm Redflex Traffic Systems. 

Under a lucrative contract that began 

in 2003, annual revenue to the city 

reached $68 million after a decade of 

operation. Among other irregularities, 

traffic tickets were issued for red-light 

violations at intersections with yellowlight 

intervals of just 2.9 seconds, 

which is shorter than the standard previously 

used. The reduced yellow interval 

time was blamed at least in part 

for an additional 77,000 tickets, which 

amounted to $7.7 million in additional 

revenue annually. Of the cumulative 

$500 million in traffic fines, Redflex 

realized about $124 million. However, 

after a whistleblower revealed a corrupt 

bribery scheme, in 2014 Chicago 

sued Redflex for $300 million. The case 

is currently in litigation. 

Problems associated with shorter 

yellow-light intervals are not unique 

to Chicago. At least one interested individual 

is Brian Ceccarelli, who is a 

science and engineering software consultant 

and owner of Talus Software, 

located in Apex, North Carolina. His 

concern is over what he believes to be 

the misapplications of physics within 

the federal guideline for yellow-light 

settings. He also sees an insidious 

relationship between the shortened 

yellow signal interval and red-light 

camera enforcement, and believes that 

municipalities can and have become 

addicted to the resulting revenue from 

automatically generated tickets. 

So it is with otherwise mundane 

traffic engineering. As even critics of 

the yellow interval formula concede, 

the length of time calculated by application 

of the scientifically based 

formula is not sufficient to ensure that 

under all circumstances, all vehicles 

approaching an intersection’s yellow 

light will have sufficient time to stop 

or proceed safely. The equation as 

written cannot handle drivers who 

brake or accelerate erratically, for instance, 

or the psychology of drivers 

whose perception and reaction times 

may not conform to those assumed. 

When the Manual on Uniform Traffic 

Control Devices requires that the yellow 

change interval be determined 

by application of “engineering practices,” 

such practices necessarily include 

using engineering judgment, 

which may not be quantifiable but is 

certainly not invidious. 

Acknowledgment 

The topic of the yellow-light dilemma was 

first brought to my attention by Alfred S. 

Goldhaber of the C.N. Yang Institute for 

Theoretical Physics at Stony Brook University. 

He referred me to Brian Ceccarelli 

of Apex, North Carolina, a graduate in 

physics from the University of Arizona 

who maintains the website redlightrobber.com. 

I am grateful to both of them for 

introducing me to this long-discussed sociotechnical 

traffic engineering problem. 

Selected Bibliography 

Ceccarelli, B., and J. Shovlin. 2013. Defying the 

laws of physics? Traffic Technology International, 

October/November:056–062. 

Eccles, K. A., and H. W. McGee. 2001. A History 

of the Yellow and All-Red Intervals for Traffic 

Signals. Washington, DC: Institute of Transportation 

Engineers. 

Federal Highway Administration. 2009. Manual 

on Uniform Traffic Control Devices for 

Streets and Highways, p. 529. http://mutcd. 

fhwa.dot.gov/pdfs/2009/pdf_index.htm 

Gazis, D., R. Herman, and A. Maradudin. 

1960. The problem of the amber signal light 

in traffic flow. Operations Research 8:112–132. 


2016 May–June 153 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Computing 

Science 

Cybersecurity Is Harder Than 

Building Bridges 

Protecting the Internet and online computerized systems from attack is a 

difficult, messy problem. Here’s why. 

Barrett Lyon / The Opte Project, opte.org 

Peter J. Denning and Dorothy E. Denning 

With a steady stream of 

reports about new cyber 

attacks and the vulnerabilities 

they exploit, it is 

easy to conclude that the overall state of 

cybersecurity is a mess. The developers 

of other engineered systems—such as 

bridges—seem to have evolved methods 

of design that keep their products 

safe and reliable. Why hasn’t this relative 

stability happened for networked 

computers? By examining a series of 

threats faced by computer systems 

engineers, and comparing them with 

those confronting bridge engineers, we 

can show significant differences that 

help explain why cybersecurity is more 

complex. But there are signs of hope for 

much better cybersecurity. 

Peter J. Denning is Distinguished Professor of Computer 

Science and director of the Cebrowski Institute 

for information innovation at the Naval Postgraduate 

School in Monterey, California. He is also editor of 

ACM Ubiquity and is a past president of the Association 

for Computing Machinery. Email: pjd@nps. 

edu. Dorothy E. Denning is Distinguished Professor 

of Defense Analysis at the Naval Postgraduate School. 

She is the author of Cryptography and Data Security 

(Addison-Wesley, 1982) and of Information 

Warfare and Security (Addison-Wesley, 1998) and 

is a member of the Cybersecurity Hall of Fame. The 

authors’ views expressed here are not necessarily those 

of their employer or the U.S. Federal Government. 

Severity of the Problem 

Cyber insecurity has become a growing 

public concern and top priority with 

governments. Recent headline-grabbers 

include the U.S. Office of Personnel 

Management data breach that compromised 

the confidential records of 22 

million federal employees, the Anthem 

health insurance system breach that exposed 

personal data of 79 million people, 

the Target Corporation heist that harvested 

credit and debit card information of 

40 million people, and the attack on Sony 

Pictures Entertainment that destroyed 

data and startup software on more than 

3,000 computers, as well as disclosed prerelease 

films and embarrassing emails of 

executives. Public officials openly worry 

about cyber attacks on critical infrastructures 

such as power, water, communications, 

and transportation. Their concerns 

are well-founded. In December 2015, for 

instance, a cyber attack against Ukrainian 

power plants shut down electricity 

to 80,000 customers. Researchers have 

demonstrated numerous vulnerabilities 

in automobiles, airplanes, and medical 

devices that could be exploited with 

deadly consequences. 

Reliable data on the extent and 

trends of cyber security incidents are 

surprisingly scarce. Security companies 

issue regular reports, but their findings 

are generally limited to data collected 

by surveys or through direct monitoring 

of their customers, and the reports 

seldom show trends beyond the fiscal 

quarter or year. David Shephard of software 

company NetIQ has extracted a 

list of 84 “most scary” facts and trends 

from multiple sources. Topping his list 

is a survey finding that 71 percent of 

organizations were victims of successful 

cyber attacks in 2014. His statistics 

show increases in detected cyber incidents, 

including a 517-percent increase 

for power and utility companies from 

2013 to 2014. The average cost per incident 

for corporations was $3.5 million 

in 2013. The U.S. Computer Emergency 

Readiness Team has also seen a rise in 

cyber incidents reported to them, growing 

more than tenfold from about 5,500 

in 2006 to more than 67,000 in 2014. The 

Center for Strategic and International 

Studies and McAfee put the annual 

cost of global cybercrime in the range 

of $375 billion to $575 billion. 

The U.S. government maintains a national 

database of all reported software 

flaws that could be exploited in cyber 

attacks; it shows a steady increase from 

1997 until about 2006, with a general 

leveling off at around 4,000 to 7,500 vulnerabilities 

per year after that. Although 

the leveling off sounds like good news, 

keep in mind that a single vulnerability 

can affect hundreds of millions of users. 

The majority of these vulnerabilities reside 

in top operating systems and applications 

software, including those from 

Apple (1,147 vulnerabilities in 2015), 

Microsoft (1,561), and Adobe (1,504). 

Considering that the desktop market 

share for Microsoft Windows and Apple 

Macintosh operating systems alone 

is greater than 95 percent, practically 

every desktop system is exposed. 

This sorry state is not due to a lack of 

concern about cybersecurity. Computer 

and information security has been an 

ongoing worry of system designers and 

operators since the 1960s. By 1965, information 

protection was taken as one 

of six fundamental concerns of operating 

systems and has remained so for 

50 years. These security technologies 

reflect a handful of basic themes: isolation, 

access control, encryption, authentication, 

and monitoring. But many 

cyber attacks are directed against the 

security technologies themselves—for 

example, guessing passwords or exploiting 

weaknesses in encryption protocols 

and antivirus software. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


The vastness of the Internet has inspired artistic visualizations of its nodes and connections. 

These images (from left to right) were built from data in 2003, 2010, and 2015. The striking increase 

in visual complexity reflects the growth of the Internet over those dozen years. In 2003 

there were 40 million websites, and in 2015, 1 billion. Any one of those sites could send you malware. 

How can you defend against an attack that could come from any of a billion directions? 

Computer Systems and Bridges 

Are other forms of infrastructure, such as 

bridges, as vulnerable to attack as cyber 

systems? Their physicality might make 

them seem easier to damage. But Wikipedia 

lists fewer than 100 bridge failures 

worldwide since 2000, and the American 

Society of Civil Engineers reports that 11 

percent of 607,000 bridges in the United 

States contain deficiencies (known vulnerabilities 

determined by inspections). 

Both of these figures, either in absolute 

or relative terms, are dramatically lower 

than those for cyber incidents and vulnerabilities. 

Our bridges are in far better 

shape than our computers. 

Computer systems and bridges have 

aspects in common. Both are engineered 

structures built from physical components. 

Their engineers work from specifications 

that give performance targets 

for critical functions. Both are concerned 

with moving traffic economically and 

efficiently—one with bits, the other with 

vehicles. Both are concerned with reliability, 

dependability, safety, and security. 

Both are susceptible, to varying degrees, 

to component and power failures, 

and external environmental factors such 

as earthquakes, floods, tornadoes, hurricanes, 

wind, aging, and traffic loads. 

Both deal with threats, although their 

nature differs. Looking at some main areas 

of threats to cyber versus bridge security 

reveals reasons why cybersecurity 

is hard and such a pervasive problem. 

Restricted Access 

Most bridges are open to the public. Although 

some require drivers pay a toll, 

they do not exclude most traffic. By 

contrast, most cyber systems are closed 

to the public, for the obvious reason 

that they are used to store and process 

sensitive information such as personal 

communications, financial data, health 

records, and trade secrets tied to individuals 

and organizations. To ensure 

that only authorized users have access, 

they require that users go through a 

login process that involves some means 

of authentication such as a password. 

All computer systems, whether open to 

public access (such as those in libraries) 

or closed, need to restrict what their 

users can do, so that they do not inadvertently 

or intentionally destroy system 

files, plant malicious code on the 

machines, or otherwise interfere with 

normal operations and other users. 

To enforce these restrictions, computer 

systems employ a complex array 

of access controls that include not only 

login mechanisms, but also isolation 

techniques enforced by the operating 

system and hardware. These controls 

must ensure that users are only allowed 

to access digital objects such as files and 

database records for which they are 

authorized, and that they are only allowed 

to perform operations and transactions 

for which they have permission. 

Implementing these controls is vastly 

more complex than installing tollbooths 

and barbed wire on bridges. 

Although the access controls of operating 

systems go a long way toward 

securing data within a computer, they 

do nothing to protect data in transit over 

networks. Indeed, most network traffic 

is vulnerable to eavesdropping and corruption. 

Protecting these data requires 

a completely different set of security 

controls—notably cryptographic methods 

for encrypting and authenticating 

data—and traffic monitors watching for 

suspicious activity. Network security 

brings up the knotty problem of surveillance—less 

of a concern in a public location 

such as a bridge, where anyone is 

able to observe the flow of traffic. 

Preventing Attacks 

Except during times of war, bridges 

are rarely openly attacked. They may 

be vandalized with graffiti or blocked 

by protestors, but even these incidents 

are infrequent in comparison with the 

constant barrage of attacks against cyber 

systems, which must be monitored 

every second of every day with tools 

such as firewalls and programs for the 

detection of intrusion and malware 

(malicious software). 

There are several reasons why cyberspace 

is a more attractive target of attack 

than bridges, but by far the most 

important is that cyber systems hold 

data of value. Intruders steal credit and 

debit card data, as in the Target breach. 

They raid bank accounts. They steal 

trade secrets and other data they can 

sell or use for competitive advantage. 

They download and disclose data to 

embarrass their victims. And they extort 

money from their victims by holding 

their data hostage or by threatening 

to disclose sensitive data acquired in a 

security breach. Even data you think 

has no value to anyone but yourself can 

be monetized with ransomware, which 

encrypts all your data and demands that 

you pay a hefty fee for the unlocking 

key. Nation-states commonly compromise 

the systems of adversaries and allies 

alike in order to acquire intelligence. 


2016 May–June 155 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Timeline of Emergence of Security Technologies 

emerging 

concerns 

security 

technologies 

Interactive 

computing. Time 

sharing. User 

authentication. File 

sharing via 

hierarchical file 

systems. Prototypes 

of “computer 

utilities”. 

Packet networks 

(ARPANET). Local 

networks (LANs). 

Communication secrecy 

and authentication. 

Object-oriented design. 

Multilevel security. 

Mathematical models of 

security. Provably secure 

systems. 

Adoption of TCP/IP 

protocols for the Internet. 

Exponential growth of 

Internet. Proliferation of 

PCs and workstations. 

Client-server model for 

network services. Viruses, 

worms, Trojans, and other 

forms of malware. Buffer 

overflow attacks. 

World Wide Web. 

Browsers. Commercial 

transactions. Data 

repositories and breaches. 

Portable apps and scripts. 

Internet fraud. Web-based 

attacks. Social engineering 

and phishing attacks. 

Peer-to-peer (P2P) 

networks. 

Botnets. Denial-ofservice 

attacks. 

Wireless networks. 

Cloud platforms. 

Massive 

data breaches. 

Ransomware. Malicious 

adware. Internet of 

Things. Surveillance. 

Cyber warfare. 

1960s 1970s 1980s 1990s 2000s 

Access controls 

Passwords 

Supervisor state 

Public-key cryptography 

Cryptographic protocols 

Cryptographic hashes 

Security verification 

Malware detection 

(antivirus) 

Intrusion detection 

Firewalls 

Virtual private networks 

(VPNs) 

Public-key infrastructure 

(PKI) 

Secure web connections 

(SSL/TLS) 

Biometrics 

2-factor authentication 

Confinement (virtual 

machines, sandboxes) 

Secure coding and 

development 

processes 

Threat intelligence 

and sharing 

Adware blocking 

Denial-of-service 

mitigation 

WiFi security 

China has been implicated in numerous 

breaches. North Korea objected to a movie 

depicting an assassination plot against 

its leader, and a group with ties to that 

country was blamed for the Sony attack. 

In addition, cyber attacks are relatively 

cheap, easy to conduct, and of 

low risk to their perpetrators. Hacker 

tool kits are simple to acquire on the 

Internet. Young hackers have long 

been attracted to the thrill of invading 

someone else’s system, whereas activist 

groups such as Anonymous have 

found cyber attacks to be a convenient 

means of protest. For criminals, cybercrime 

is a lower-risk alternative to traditional 

heists, such as bank robberies. 

User Error 

Cyber systems are much more prone to 

the weaknesses of their human users 

than are bridges, where careless drivers 

are unlikely to do more harm than tie 

up traffic or damage a guardrail. 

Ignorant and careless users pose ongoing 

risks to cybersecurity. They pick 

weak passwords, open attachments 

with malicious software, click on links 

that lead to malicious sites, lose their 

laptops and other portable devices, 

and fall for phishing scams that harvest 

their usernames and passwords. 

Even careful users can be victimized 

by a “drive-by download” attack if 

they visit a legitimate site that has 

been compromised and are injected 

with malware that automatically infects 

their computer. 

In addition to users, system administrators 

can be a source of vulnerabilities—for 

example, by failing to configure 

their systems for security, install patches, 

remove obsolete accounts, or respond 

to security alarms. Administrators need 

to install patches quickly for newly discovered 

vulnerabilities, but a speedy response 

does not always happen. Kenna 

Securities found that it takes companies 

on average 100 to 120 days to install 

patches, even though the probability of 

a vulnerability being exploited reaches 

90 percent within 60 days. 

Part of the reason that users fall 

short is that security is often inconvenient, 

interfering with their ability 

to accomplish their goals. Users do 

not like using 15-character passwords 

such as “7t$xKQ34(2@ad9#” or installing 

updates when they are busy with 

other things. They have difficulty using 

encryption and recognizing emails 

with malicious attachments and links. 

Some do not perceive the dangers and 

will bypass security protections and 

rules in their workplaces in order to 

get their jobs done more quickly. 

Code Complexity 

Cyber systems are enormously complex. 

The two major desktop operating 

systems, Windows 10 and Mac 

OS 10.4, use 50 million and 86 million 

lines of code, respectively. No bridge 

has so many components. 

Each line of code in an operating 

system potentially contains errors that 

could be exploited to compromise security. 

Finding and removing vulnerabilities 

in 50 million lines of operatingsystem 

code is devilishly hard for developers, 

which is why thousands of 

new errors are revealed each year. Add 

in software applications—including 

browsers, email, database systems, and 

document processing tools—and the 

problem quickly becomes intractable. 

Further, even if software products are 

shipped with no known security flaws, 

backdoors and malicious code can be 

inserted somewhere along the supply 

chain. Rogue retailers, for example, 

have been reported to install datacollecting 

malware on Android phones 

made and largely sold in China. 

To make matters worse, cyber systems 

are dynamic and constantly evolve. 

Whereas the American Society of Civil 

Engineers reports the average lifetime of 

bridges to be 42 years, software systems 

have much shorter lifetimes, measured 

in years rather than decades. Software 

systems are constantly upgraded—and 

the new and revised components often 

have novel vulnerabilities. In contrast, 

bridges are stable over their lifetimes, 

seldom require replacement parts, and 

need only periodic physical maintenance 

such as painting and inspections. 

On top of all this, there are theoretical 

limits to cybersecurity. In the 

1980s, security pioneer and computer 

scientist Frederick B. Cohen proved 

that it was impossible to develop an 

antivirus tool that would detect all 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


possible computer viruses. We are unaware 

of any theoretical limitations to 

constructing safe bridges. 

Connectivity 

Almost by definition, cyber systems 

are joined up with one another. Attacks 

can come from any direction and 

their sources can be made untraceable. 

Bridges are not so immediately interconnected; 

an attack or failure on one 

cannot spread to another. 

Viruses and worms were some of the 

first lines of automated attacks enabled 

by network connectivity in the 1980s. 

The infamous Morris Worm of 1988 took 

down 10 percent of the Internet at the 

time in a few hours and stimulated the 

formation of the Computer Emergency 

Response Team at Carnegie Mellon University. 

Malware has become so ubiquitous 

that antivirus software has become 

a major industry. The Anti-Phishing 

Working Group reported that in the first 

quarter of 2015, the global malware infection 

rate was 36 percent. Norway had 

the lowest rate at 20 percent, and China 

the highest at 48 percent. 

Attacks on bridges require some 

sort of physical presence such as a 

bomb, an aerial attack, or a mass protest. 

In contrast, remote attacks are 

common in cyberspace. The address 

from which you were directly attacked 

is probably not that of the perpetrator, 

because most attackers relay through 

multiple hosts to confound attribution. 

Connectivity has also enabled attackers 

to assemble large networks of compromised 

computers, called botnets, and 

use them to conduct attacks and send 

out spam. They are particularly popular 

for conducting distributed denial of 

service (DDoS) attacks, which flood the 

chosen target with traffic and thus shut 

it down. Peak floods have reached hundreds 

of gigabits per second of traffic, 

causing major disruptions. In late 2012 

and early 2013, an Iranian group shut 

off access to several bank sites with 

DDoS attacks reaching 120 gigabits per 

second, as a means of protest. 

One of the biggest security concerns 

is the emergence of the Internet 

of Things, which has been enabled by 

cheap wireless technology. Another factor 

has been a change in the standard 

for Internet addresses to increase the 

number of digits from 32 to 128, which 

has expanded available addresses from 

about 4.3 billion to a basically unlimited 

number—more than 3.4 x 10 38 . Now 

virtually every device and appliance 

can be connected to the Internet. The 

burgeoning Internet of Things is widely 

regarded as a potential security disaster 

because designers of individual things 

often pare down their operating system 

to bare essentials, such as wireless 

connections, and do not preserve security 

technologies. These devices contain 

many more vulnerabilities than do 

commercial operating systems. 

Cyber systems are now an essential 

component of every infrastructure 

and are embedded in industrial controls 

systems. They are used to operate 

power grids, manage transportation 

systems, handle finances, move oil and 

gas, treat and distribute water, operate 

dams, and much more. Thus, an 

attack on a cyber system can have consequences 

that go well beyond computers 

and the data that they store, 

and can be a means of damaging many 

physical systems. Public officials and 

security professionals are increasingly 

concerned that devastating cyber 

attacks against critical infrastructure 

could lead to loss of life and have a 

huge economic impact. 

Market Forces 

Absolved by licensing agreements, cyber 

software vendors are generally not 

legally liable for flaws in their products. 

We are forced to accept their products 

“as is.” Bridge builders, by contrast, are 

subject to legal action in the event of 

failures owing to faulty construction. 

In addition, software companies are 

under tremendous pressure to get their 

products to market. If they spend too 

much time in development, they will 

lose market share when other companies 

beat them to the consumer. One 

consequence is that vendors limit the 

amount of time they spend hunting for 

and fixing vulnerabilities. A survey by 

the security software company Prevoty 

found that 79 percent of companies 

release applications with known bugs; 

nearly half reported releasing apps 

with known vulnerabilities at least 80 

percent of the time. More than 70 percent 

said that business pressures often 

overrode security concerns, whereas 

85 percent said that vulnerability remediation 

significantly affected their 

ability to release software on schedule. 

On the other hand, companies 

whose computer systems are attacked 

are more often being held liable for the 

harm it causes their customers. To settle 

a class-action lawsuit following its 

security breach, Target set up a fund of 

$10 million for customers whose card 

payment data were compromised. 

Is There Hope? 

Although the state of cybersecurity 

seems bleak, not all of the news is bad. 

Software developers now take security 

much more seriously than they did at 

the turn of the century. They heed their 

customers’ calls for more security for the 

personal data entrusted to them, and 

they cringe at lawsuits that will surely 

follow a damaging attack. Microsoft, for 

example, uses Security Development 

Lifecycle (SDL), a software development 

management process they created to enforce 

secure coding practices. Adopting 

SDL has significantly reduced the number 

of vulnerabilities in their software. 

The software industry’s greater emphasis 

on security is no doubt one reason that 

the number of reported vulnerabilities 

has flattened out in recent years. Even so, 

many see security not as the top priority 

but as a tradeoff with other objectives, 

such as functionality and performance. 

The cyber security community has 

also responded to the growing threat 

with new technologies and guidelines 

for operating cyber systems securely. 

Although no single security technology 

can make a system secure, using 

them together with recognized security 

practices provides many impediments 

to intruders and malware. The 

federal government and industry have 

developed a list of 20 critical security 

controls, and if everyone adopted 

these protocols, we would see a dramatic 

drop in successful cyber attacks. 

Moreover, with help from industry, 

governments are taking greater steps 

to go after those responsible for cyber 

attacks and to shut down botnets and 

sites used to distribute malware and 

support cyber attacks. Governments 

and industry are sharing more threat 

intelligence so that organizations can 

better protect their systems. 

Although cyber attacks certainly have 

been on the rise, so too has the use of 

cyber systems. An interesting study by 

Eric Jardine of the Centre for International 

Governance Innovation in Canada 

finds that relative to the growth of the 

Internet, many measures of insecurity 

growth show it slowing down or even 

declining. Such results are encouraging; 

at the least, they suggest that the threat is 

not getting too far ahead of us. 

(A reference list for this article is available at 

http://www.americanscientist.org.) 


2016 May–June 157 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Energy–Water Nexus: 

Head-On Collision or Near Miss? 

Energy production requires water, and clean water requires energy. How will 

we overcome this feedback loop in a warming, increasingly crowded world? 

Kristen Averyt 

One year ago, U.S. Secretary 

of Energy Ernest Moniz 

warned that the ongoing 

drought in California could 

bring brownouts, and that climate 

change could create more challenges 

for power plants. Moniz linked this risk 

to hydropower. But the reliability of 

energy production and its connections 

with drought and climate are far more 

complex than his remarks suggest. 

Since the onset of the California 

drought in 2011, the amount of electricity 

generated by hydropower has declined 

from 23 to 9 percent. To make up 

the difference, by 2014 wind power had 

doubled its contribution to 8 percent 

and utility-scale solar power had increased 

to 5 percent; but electricity production 

by natural gas also increased. 

The result was an 8 percent increase in 

the state’s carbon emissions from 2011 

to 2014, because natural gas is mostly 

methane, a potent greenhouse gas. Agriculture 

complicates predictions about 

energy production and water use. 

Through 2015, the industry has suffered 

a loss of over $2.7 billion in revenue 

since the onset of the drought. Of that 

amount, $590 million can be attributed 

to the cost of the energy needed to 

pump groundwater as surface water 

availability has declined. That cost has 

been passed on to the consumer in food 

prices across the United States. 

For parched Californians who need 

drinking water, a desalination plant 

that turns seawater into freshwater just 

began delivering up to 189,000 cubic 

Kristen Averyt received her PhD from Stanford 

University in 2005. She is currently the 

associate director for science at the Cooperative 

Institute for Research in Environmental 

Sciences (CIRES) at University of Colorado 

Boulder. Email: ________________ 

kristen.averyt@colorado.edu. 

meters of water to those in the San Diego 

region. Although it is the most efficient 

desalination plant on the planet, it 

will still use 300 million kilowatt-hours 

of energy and increase the amount of 

carbon emissions attributable to production 

of the state’s water supply. 

Energy production requires water, 

and water treatment and distribution 

require energy. Both energy and water 

demands are stressed by climate 

change and population growth, but efficiency 

in one sector does not necessarily 

translate to efficiency in the other. As 

the problems with rising temperatures, 

increasing droughts, growing energy 

demands, and escalating water needs 

collide, it becomes clear that solutions 

to each problem must consider cascading 

effects on the others. 

By 2050, the world will be a fundamentally 

different place than it is 

today: The population on our planet 

could exceed 9.7 billion people, and 

global temperatures are expected to 

be about 1 degree Celsius hotter than 

today. Those changes, in turn, will lead 

to many others, because the water cycle 

will be different and because more 

people could mean more energy use. 

The way that water is cycled among 

atmosphere, land, and water bodies 

will change, because as temperatures 

increase, the atmosphere holds more 

water, causing a shift in both the Earth’s 

energy balance and the relative distribution 

of water among the components 

of its cycle. This shift will drive expansion 

of the latitudinal boundaries of the 

planet’s deserts, change precipitation 

patterns, and decrease water availability 

across much of the planet. 

More people could mean increased 

demand for energy. Indeed, per capita 

energy use varies from 0.8 megawatthours 

in India to 3.8 megawatt-hours 

in China to as much as 5.4 megawatthours 

in the United States. But a consistent 

trend is that access to electricity 

is key to combating poverty and malnutrition. 

With more intense and more 

frequent heat waves, we will need even 

more power to manage public health 

and safety during the summer months. 

Decision makers operating at every 

scale of governance are working toward 

creating water and energy systems that 

are resilient to a hot and crowded future. 

But just as scientists tend to consider 

climate impacts as isolated sectors, 

so do those managing resources and 

assessing vulnerabilities. When each is 

considered through a single lens, the 

full range of risks and prospects may 

not be apparent, leading to surprise impacts 

and missed opportunities. 

The so-called energy–water nexus illustrates 

how one sector may compromise 

efforts by another when it pursues 

in isolation what it deems to be an optimal 

strategy for dealing with the future. 

The term energy–water nexus was 

coined in the 1990s by a small group of 

scientists working in national laboratories 

tasked with assessing what the 

Department of Energy identified as an 

emerging field of risk: interdependencies 

between water and power. 

Water for Energy 

Water is required at each step in the process 

of energy production (see the figure 

on page 160). From resource extraction 

through refining, to transportation of fuels 

and electricity generation, it is really 

water that powers the planet. But in this 

process, by far the most water is used 

during thermal generation, when heat 

is converted to electric power. It may 

surprise some to learn that the water 

required to run thermoelectric power 

plants accounts for the largest part of 

Lenny Ignelzi/AP Photo 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


A new desalination plant that turns seawater into freshwater in Carlsbad, CA, went into operation 

in December 2015 and is emblematic of the need to consider effects on water and energy 

concomitantly. Although it is the most efficient desalination plant worldwide, it still uses an 

energy-intensive process. The energy–water nexus is an area of study focusing on optimizing 

solutions for energy and water efficiency, so that solving one problem does not create another. 

energy’s water footprint. A key challenge 

for the future, then, is to design 

an electricity system that will meet the 

power demands of a growing population 

during heat waves and droughts, 

when energy demand for air conditioning 

is high and water supply is low. 

Globally, 15 percent of all the water 

used supports electricity generation. 

In the United States, because we 

use more electricity per capita than 

most countries (5.4 megawatt-hours), 

45 percent of all the water withdrawn 

in a given year is used in energy production 

(161 million gallons per day is 

used to run power plants—more than 

the 117 million gallons used daily to 

grow food and to feed livestock). 

Power plants use all this water because 

most of them use heat to make 

power and therefore need water for 

cooling. Most power plants generate 

electricity using a process that first 

turns thermal energy into work. These 

thermoelectric power plants operate 

by burning a fuel, such as coal or natural 

gas, which heats up a reservoir of 

water. As the water boils, the steam 

produced rotates a turbine, which 

generates electricity. Next, the steam 

is condensed so that it can be reheated 

to generate even more steam, and then 

the cycle can continue. The most efficient 

way to condense the steam is 

to pass cold water through the system. 

That demand for cooling water accounts 

for over 95 percent of all the water 

used to produce energy. The reason 

water is optimal for cooling is because 

of its high heat capacity. The hydrogen 

bonds in water allow the molecules to 

hold a relatively large amount of energy, 

making the introduction of lots 

of cold water into the system the most 

efficient way to move heat out. 

The end result of this process is that 

thermoelectric power generation is 

dependent on a continuous supply of 

cool water. In the United States, roughly 

90 percent of our electricity comes 

from this type of power plant, which 

is why so much of the domestic water 

budget is used by the electricity sector. 

But nuclear power plants can use even 

higher amounts of water for cooling 

than do other thermoelectric plants. 

When discussing the energy–water 

nexus, most of the focus is on thermoelectric 

plants, because hydropower 

does not “use” water in the same sense 

as these power sources, except for 

evaporation that may occur on a reservoir 

built to support a hydroelectric 

dam. Still, hydropower is an important 

electricity source, particularly in 

the Pacific Northwest, where climate 

change is not expected to cause problems 

with drought but is expected to 

change the timing of water arrival as it 

melts from mountain snowpack. 

Exactly how much water is used 

by any of the more than 1,700 operational 

thermoelectric power plants in 

the United States depends on several 

factors, of which the most important 

is how cooling water is continuously 

supplied to the power plant. 

About 47 percent of our electricity 

comes from power plants that use 

what’s called a once-through process. 

These types of power plants are located 

on rivers, streams, lakes, and coastlines. 

The nearby water flows through 

the power plant and then is returned 

back to the source. Other power plants, 

particularly those located in arid regions, 

use a recirculating system. These 

systems use evaporation to remove 

heat from the cooling water after it has 

passed through the condenser, either in 


2016 May–June 159 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


small ponds where evaporation occurs 

naturally, or cooling towers, which accelerate 

the process. 

Each technology type has tradeoffs 

related to water withdrawals, consumptive 

use, and water quality. Using 

evaporation to pull heat from cooling 

water consumes, through evaporation, 

2 to 30 times more water per unit of 

electricity generated (kilowatt-hour) 

than is consumed by a once-through 

facility. On the other hand, a power 

plant using once-through cooling will 

withdraw as much as 60 times more 

water per kilowatt-hour than will a 

plant that uses evaporative cooling. 

Although the majority of the water 

from these power plants is returned to 

the source, the temperature of that water 

is, on average, 10 degrees Celsius 

warmer than when it came into the 

power plant, making power plants the 

top source of aquatic thermal pollution 

in the United States. 

Most of the once-through power 

plants in the nation are located in the 

eastern United States, where there are 

abundant surface water resources to 

support the large water withdrawal 

requirement. In the West, evaporative 

cooling is the predominant technology 

because of the lack of ample water, so 

these power plants pay the penalty of 

a larger consumptive footprint. These 

differences create distinctive vulnerabilities 

for each half of the country. 

Over the past 10 years, power plants 

have encountered problems generating 

adequate power because of insufficient 

water. Not surprisingly, these collisions 

at the energy–water nexus have generally 

occurred during heat waves and 

droughts. Here’s what happens: When 

it’s hot outside, air conditioners are 

cranked up, and power plants go into 

high gear. Turning up the power means 

that more water moves through the 

plants. Problems emerge when there 

Water is used in every step of the energy production process, especially for converting heat into 

energy in thermoelectric power plants. Of all water used for energy, 95 percent goes to cooling 

steam to condense it back into water for reuse. Although water use varies by fuel source, oncethrough 

plants that use water from a nearby water body and then return it after it is recondensed 

withdraw more water than do plants that use evaporative cooling in towers. But evaporative cooling 

consumes more water overall, because the lost water vapor is not reused. (Data from J. Meldrum, 

S. Nettles-Anderson, G. Heath, and J. Macknick. Environmental Research Letters 8:015031.) 

isn’t enough water to meet these elevated 

electricity demands. During the 

2012 drought in Texas, a reservoir serving 

the 2,250-megawatt Martin Lake 

power plant dropped so low that the 

operating company rushed to complete 

a pipeline that brought in water from 

a river 8 miles away. Climate models 

predict both higher temperatures and 

more drought in many regions. Places 

like Texas made it through droughts 

such as the one in 2012 but may face future 

energy problems in addition to the 

more obvious water-supply problems. 

Another issue has to do with water 

temperature. If the cooling water 

coming into a plant is too warm, the 

thermodynamic process is no longer 

efficient, and electricity production 

drastically declines. And in the case 

of a nuclear power plant, without 

sufficient cooling water to move heat 

away from the nuclear core, a nuclear 

meltdown can occur. Some eastern 

power plants routinely have to curtail 

production because of increased temperatures 

in cooling water, and nuclear 

plants in particular have been forced 

to shut down. This happened at the 

now-retired Vermont Yankee Nuclear 

Power Plant in July 2012. During that 

month, the facility had to limit electric- 

Water Use for Energy Production 

natural gas extraction 

4 – 45* 

transport 

15 – 30* processing 

cooling tower 

965 – 4,554* 

power plant 

electricity 

uranium mining 

extraction 

57 – 121* 

coal mining 

extraction 

11 – 170* 

processing 

68* 

transport 

4* 

nuclear disposal 

4 – 2,725* 

cooling tower 

1,488 – 3,804* 

* cubic meters per gigawatt-hour 

power plant 

power plant 

processing 

4 – 314* 

outgoing 

warm water 

cooling tower 

4,168* 

power plant 

power plant 

cool water 

intake 

once-through 

85,512 – 137,600* 

outgoing 

warm water 

power plant 

cool water 

intake 

once-through 

167,883* 

river 

outgoing 

warm water 

cool water 

intake 

once-through 

43,078 – 132,489* 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Withdrawals 

(cubic meters 

per megawatt 

hour) 

227 

189 

151 

114 

76 

38 

0 

Nuclear 

once-through 

Coal 

Biopower 

cooling pond 

Natural gas 

combined-cycle 

Coal 

Nuclear 

Nuclear 

Water use varies by both power source and cooling technology, so that 

low-carbon power is not necessarily low-water. Once-through cooling, 

which withdraws water from a water system and returns it later 

at a higher temperature, uses less water overall than an evaporative 

system. No water is required for dry cooling, which uses cold, dry air 

to condense steam, but this technology is only feasible in cold, dry 

Coal 

recirculating 

CSP trough 

Natural gas 


CSP trough 

Biopower 

dry-cooled 

Natural gas 


Photovoltaic 

Natural gas 

combustion turbine 

Wind 

Consumption 

(cubic meters 

per megawatt 

hour) 

Nuclear 

4.5 

3.8 

Coal 

3.0 

Biopower 

2.3 

Natural gas 

1.5 

Solar 

0.8 

0 

Wind 

median 

climates or at certain times of year. Thus, power sources that seem 

optimal because they are low carbon, such as solar or nuclear power, 

may exacerbate water supply issues, depending on their cooling 

technology. (Figure from K. Averyt, et al., 2011. Union of Concerned 

Scientists; data from J. Macknick, R. Newmark, G. Heath, and K. Hallett. 

Environmental Research Letters 7:045802.) 

ity production multiple times because 

of low flows on the Connecticut River 

and high water temperatures. 

Elevated temperatures are not just 

a problem for power-plant operations. 

If the water entering a plant is already 

warm, the effluent is even hotter, which 

can create problems for aquatic ecosystems. 

Some bass species can tolerate 

high temperatures, but a rainbow trout 

thrives in waters around 14 degrees 

Celsius and generally cannot survive in 

temperatures above 24 degrees Celsius. 

In some states, there are limits on effluent 

temperatures to protect fish. But 

given the need to ensure public health 

during extreme heat waves, power 

plants are often granted waivers so that 

they can use warm water to operate, 

and the water that is returned is much 

hotter. For example, during the heat 

wave in 2012, the Braidwood Nuclear 

Power Plant outside Chicago was one 

of at least 29 power plants in the state 

Monticello 

Sault Ste. Marie 

Vermont 

Yankee 

Leland Olds Station 

Pilgrim 

Bonneville Power 

Great River Energy 

Prairie Island 

Will County 

Limerick 

Millstone 

Laramie River 

Joliet 

Arnold 

Quad Cities 

Cook 

Perry 

Dresden 

Hope Creek 

Calvert Cliffs 

California 

ISO 

North Platte Project 

Powerton 

Braidwood 

Gallatin 

Cumberland 

GG Allen 

ED Edwards 

Hoover Dam 

LaSalle County 

TVA dam network 

Riverbend 

Browns Ferry 

Southern Co. 

Hammond 

Branch 

When water is too hot for cooling or when water supplies 

dwindle in dry or high-demand months, power plant 

operations must be shut down or curtailed. Also, if effluent 

water is warm enough to pose a risk to aquatic life, a 

plant may be required to limit operations. Such disruptions 

to the power supply, which have occurred at the 

plants shown on the map, are becoming more common in 

a changing climate with a growing population. (Adapted 

and updated from J. Rogers, et al. 2013. Water-Smart 

Power. Cambridge, MA: Union of Concerned Scientists.) 

Martin Lake 

Yates 

coal nuclear hydro 

not enough water 

water too warm 

snow and ice storm 

outgoing water too warm 

incoming water too warm 

Hatch 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


seawater 

(desalination) 

wastewater reuse 

1,000 cubic meters = 264,000 gallons 

1,233 cubic meters = 1 acre foot 

wastwater 

treatment 

groundwater 

lake or river 

0 

2 4 6 8 10 

megawatt-hours 

per 1,000 cubic meters 

Locations where water demands outstrip local supply are highlighted in red, orange, 

and yellow on the map. People in these places adapt to low water availability by 

bringing in water from other locations, overpumping groundwater, or recycling 

water—all of which are energy-intensive practices—or by relying on return flows 

or reservoir storage. The more the water supply is stressed, the more challenging 

it becomes to meet these demands with an energy-efficient solution, because some 

water treatment and delivery strategies use much more energy than others (chart). 

(Map from K. Averyt, et al. 2013. Environmental Research Letters doi:10.1088/1748- 

9326/8/3/035046; data in graph from World Business Council for Sustainable Devel- 

of Illinois granted a variance allowing 

effluent temperatures to exceed 32 

degrees Celsius—the limit set by state 

law. In the Southeast, striped bass kills 

on Lake Norman in North Carolina 

have been linked on multiple occasions 

to high water temperatures associated 

with nuclear power generation. 

Keeping the power on is not only 

important so that we can charge our 

laptops. It is a matter of public health 

and safety. When the lights go out, 

those who rely on electronic medical 

devices and those vulnerable to the 

Case Study: Fracking for Natural Gas 

heat, including the elderly, are at significant 

risk. In August 2003 alone, 

almost 45,000 heat-related deaths occurred 

across Europe, in part because 

nuclear power plants were not able 

to sustain operations. The water was 

too hot, and the demand was too 

high. Another ominous climate trend: 

Heat waves become doubly dangerous 

when they also disrupt the power 

needed for air conditioning. 

Newer cooling technologies that require 

no water address some of these 

problems, but they work best in very 

water supply stress index (WaSSI) – withdrawal all 

demands, average surface supplies 1999–2007 

0.00–0.20 

0.21–0.40 

0.41–0.60 

0.61–0.80 

0.81–1.00 

1.01–2.00 

2.01–3.00 

3.01–4.00 

4.01–5.00 

5.01–47.30 

cold, dry regions with Siberian-type 

climates. Dry cooling circulates cold, 

dry air through the system to absorb 

heat and condense steam. Hybrid technologies 

that can switch between wet 

and dry systems are now sometimes 

used, particularly at new power plants 

being constructed in the western United 

States. But in operational settings, 

dry cooling is efficient only when outdoor 

temperatures are relatively low. 

Given that dry cooling is most useful 

in an arid desert, where it also tends 

to get warm in the summer months, 

About 50 percent of both the domestic crude oil and 

natural gas supplies are produced by hydraulic fracturing. 

This process uses relatively modest quantities 

of water—generally between 7,600 and 18,900 cubic meters 

per well—depending on regional geology. By comparison, a 

250-megawatt coal-fired power plant would evaporate roughly 

11,300 cubic meters in a day. In Colorado, although natural 

gas production has doubled since 2001, less than 1 percent of 

the state’s total water is used for hydraulic fracturing. However, 

because water used in hydraulic fracturing is contaminated 

and thus taken out of the water cycle, and because such activities 

are concentrated in areas where natural gas is available, 

water for extraction becomes important locally. 

Another consideration is fugitive emissions associated 

with hydraulic fracturing. Natural gas is mainly methane, 

a greenhouse gas that is 25 times more potent than carbon 

dioxide. Although the amount of methane varies, it’s clear 

that some of this gas escapes during the hydraulic-fracturing 

process. In some cases, that amount is not trivial. 

Water tanks are set up for a hydraulic fracturing job. Although this 

natural gas extraction technique uses relatively modest quantities 

of water, in some locations there already is not enough to go around. 




qM 

qM q 

qM q 

M 

M 

Qmags 




WYOMING 

qM 

qM q 

qM q 

M 

M 

Qmags 


Joshua Doubek/Wikimedia Commons 

CALIFORNIA 

Bay Delta 

Conservation Plan 

State 

Water 

Project 

Pacific 

Ocean 

NEVADA 

Mokelumne Aquaduct 

Hetch Hetchy Aquaduct 

Colorado 

River Aquaduct 

fully operational 

under construction 

Central Utah 

Project 

plants would still need to switch to 

cooling water when temperatures get 

too high. Fortunately, newer dry and 

hybrid cooling technologies are emerging 

that do not have this problem. 

Western thermoelectric power 

plants have generally avoided waterrelated 

curtailments, because they are 

fairly well adapted to their low-water 

environments. Almost all of them use 

evaporative cooling, so the immediate 

availability of large quantities of 

water is not as important as it is for a 

once-through facility. Also, a large proportion 

of western power plants are 

fueled by natural gas and renewables, 

whereas those in the east are more 

likely to use coal or nuclear power. 

And the fuel source matters for water 

use just as much as it does for greenhouse 

gas emissions. 

To illustrate this concept, consider 

a hypothetical 250-megawatt coalfired 

power plant that has a 75 percent 

capacity factor and uses evaporative 

cooling towers. That plant would 

withdraw approximately 6 million 

cubic meters of water per year and 

consume 4 million cubic meters. If 

the operating utility were to opt for a 

lower-carbon technology, they might 

consider nuclear power. But the water 

intensity of power generation in a 

nuclear plant would be about 10 percent 

greater for withdrawals than that 

of the original coal-fired plant, because 

more cooling water is required to pull 

intense heat away from the nuclear 

core. And, surprisingly, a wet-cooled 

concentrated solar power plant would 

use just as much water as a nuclear facility, 

if not more. Concentrating solar 

power, such as the 280-megawatt Solana 

Generating Station in Arizona, uses 

a thermoelectric process; therefore, 

cooling, whether by water or cold air, 

is still necessary, even though the Sun 

provides the thermal energy source. 

If that coal-fired power plant were 

to switch to a natural gas source that 

uses an integrated gasification combined 

cycle (which turns fuel into a 

clean gas that burns extremely efficiently), 

the water use (both in terms of 

withdrawals and consumption) at the 

plant would be cut by about 70 percent 

per unit of electricity produced, 

and carbon emissions would be cut by 

roughly 40 percent. 

The benefits of a switch from coal 

to natural gas have included a decline 

in the rate of annual greenhouse gas 

emissions by the United States. However, 

burning natural gas still emits 

carbon. And there are fugitive methane 

emissions at the wellhead and in 

the midstream sectors. So, depending 

on the evolution of future energy demands, 

a natural gas future has the 

potential to offset its current carbon 

benefits. 

Researchers and technologists have 

been testing carbon capture and storage 

technologies, along with the practicality 

of coupling this technology 

with coal and natural gas facilities. Doing 

so would greatly ameliorate carbon 

emissions, but it could also more 

than double the water intensity of electricity 

generation, because the process 

by which carbon is captured is energy 

intensive, requiring even more cooling 

water. So when it comes to electricity, 

low-carbon choices are not necessarily 

low-water choices. But they can be. 

Both wind and photovoltaic electricity 

sources require very little, if any, 

water to operate. A trivial amount of 

water may be used for washing solar 

panels and wind turbines, but in practice, 

power plants don’t require cleaning. 

Water is used in the production of 

wind and solar power largely at the 

front end, for mining, processing, and 

fabrication. That’s not to say that any 

of these technologies are perfect. They 

have their own set of challenges related 

to land use, wildlife habitat fragmentation, 

and optimization of grid 

integration. In the design of power 

plants that can handle the heat, there 

will be complex tradeoffs to consider 

in order to manage the cascading risks 

associated with ensuring a reliable 

electricity supply with limited water. 

UTAH 

Central Groundwater 

Valley Development Project 

Project Project 

COLORADO 

Lake Powell 

Los Angeles Aquaduct Pipeline 

Cadiz Water Project 

ARIZONA 

Central 

Arizona 

Project 

Regional Watershed 

Supply Project 

Colorado 

Big Thompson 

Project 

Yampa River 

Pumpback 

NEW MEXICO 

San Juan 

Chalma 

Project 

Northern 

Integrated 

Supply Project 

Southern 

Delivery 

System 

TEXAS 

In areas where water demands outstrip supply, pipelines are planned or under construction to 

bring in water from other areas, which also requires energy. 

Energy for Water 

As water scarcity grows in drier areas, 

transporting it and treating it becomes 

more energy-intensive. Addressing the 

other side of the energy–water nexus 

is a greater challenge in a changing 

climate, because there is less water to 

go around. 

Exactly how much power is used 

globally to ensure adequate water supplies 

is, at best, a guess. Even in the 

United States, the best estimates suggest 

that pumping, conveying, and 

cleaning water requires 3 percent of the 

total electricity supply (13 percent when 

heating water is considered), compared 

with the 5 percent of the electricity supply 

that is used for air conditioning. But 

even those data are hard to corroborate. 

Of course, ensuring access to a clean, 

safe water supply requires energy. But 

the energy intensity of that water varies 

significantly, depending on location. 

For instance, a New Yorker would use 

0.7 kilowatt hours per cubic meter of 

water, whereas the energy embedded 

in the water supply of a resident in 

southern California would be almost 5 

times that amount. 

Let’s break that down a bit: For 

the New Yorker, the energy intensity 

of water is embedded primarily 

in the distribution of drinking water 

and in wastewater treatment. Across 

the country, there are approximately 

160,000 publicly owned drinking water 

plants, and another 16,000 water 

treatment plants. At drinking water 

plants, 80 percent of the energy required 

goes to pumping, making power 

the second-highest budget item after 

labor. On the water treatment side, 


2016 May–June 163 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Denver, CO 

Albuquerque, NM 

Phoenix, AZ 

Poenix, AZ (CAP) 

Tucson, AZ (CAP) 

Las Vegas, NV 

1 2 3 4 5 

megawatt-hours per acre-foot 

Adbar/Wikimedia Commons 

More than 20 percent of Arizona’s water is brought in from the Colorado River via the Central 

Arizona Project (CAP) aqueduct across 541 kilometers, requiring 2.8 million megawatt-hours 

of electricity a year. Most of that power (90 percent) comes from the Navajo Generating Station 

(right), a coal-fired power plant that is one of the top three carbon emitters in the nation. Almost 

a quarter of the electricity it generates is used by CAP, making the carbon footprint of this water 

supply one of the country’s highest. (Data from S. Tellinghuisen. 2011. Energy-intensive water 

supplies. In The Energy-Water Nexus in the American West. Northampton, MA: Edward Elgar.) 

power is needed for aeration, pumping, 

and solids processing. For this reason, 

25 to 40 percent of the operating 

costs of a wastewater utility are for 

energy. And the dirtier the water, the 

more power is necessary. 

For a westerner, the energy intensity 

of water tends to be greater, because 

the energy required for basic waterplant 

functions is compounded by the 

need to store and then move water long 

distances from the source to population 

centers in dry places. In 1907, the 

federal government established what 

is today called the Bureau of Reclamation 

and gave it the mission of developing 

and managing water resources of 

the West. Twenty years later, construction 

began on Hoover Dam, the Bureau’s 

first large-scale project. The dam 

blocked part of the Colorado River, creating 

what is still the largest reservoir in 

the country—Lake Mead. This marked 

the beginning, not of how the West was 

won, but of how it was plumbed. 

This tradition of managing water to 

support development continues today. 

Over 4,800 kilometers of pipelines, canals, 

and aqueducts transport roughly 

the same amount of water that flows 

annually in the Colorado River—14.8 

cubic kilometers. However, all trips 

are not equal. Conveying water across 

flat land requires very little power, and 

water flowing downhill can generate 

power, but moving water upward— 

either from the ground or over 

mountains—demands a lot of energy. 

Although the energy penalty of 

groundwater withdrawals may seem 

trivial, the costs add up. As mentioned 

earlier, a case in point is California. 

Revenue losses there of $2.7 billion 

during recent dry years are not solely 

the result of crop losses; over 20 percent 

of that cost is due to added spending 

on the electricity needed to pump 

more groundwater as surface water 

supplies diminish. 

Given the power required to move 

water a couple of hundred feet to get it 

out of the ground, it’s no surprise that 

the energy intensity of the Southwest’s 

large conveyance systems that pump 

water over mountains is far greater. 

The large-scale surface-water complex 

that moves water, particularly 

from the Colorado River, through the 

Western landscape makes some of the 

region’s water providers the largest users 

of electricity. In Arizona, the largest 

user is the aqueduct called the Central 

Arizona Project (CAP)—the perfect example 

of the potential conflict inherent 

to the energy–water nexus. 

Over 20 percent of Arizona’s water 

supply is brought in from the Colo- 

Win-Win Low-Carbon Solutions? 

Although the majority of the U.S. power sector runs 

on water, there are low-carbon, low-water options 

currently operating in the United States and 

abroad. The trick is to match the long-term availability 

of the renewable resource to the appropriate power plant 

technology. 

Although the Sun shines in deserts, where water for 

cooling is often limited, solar power can still be an option. 

Large-scale photovoltaic farms, a scaled-up version of 

the panels found on the rooftops of almost 500,000 homes 

across the United States, require little to no water to operate. 

The Topaz Solar Station, commissioned in southern California 

in 2014, is a 550-megawatt facility that reports no water 

use. The Ivanpah Solar Electric Generating System in the 

Mojave Desert is a 392-megawatt concentrated solar thermal 

power plant that employs dry cooling, and therefore 

requires 90 percent less water than a solar plant that uses 

cooling water. And the Palo Verde Nuclear Power Plant in 

Arizona is the only nuclear facility in the world that uses 

only recycled wastewater for cooling. 

Although these examples use little water and emit little 

carbon in terms of their operations, there are still impacts 

that power plants must plan for and actively manage. Initial 

plans for development of the Ivanpah facility were altered 

to accommodate critical habitat for the endangered desert 

tortoise. And, once operational, the power towers that focus 

the sunlight were found to burn birds flying across the concentrated 

sunbeams. Photovoltaic panels are made of rare 

earth minerals, which are extracted from specific regions of 

the globe where the resources exist, using methods that can 

compromise the local environment. The photovoltaic cells 

used by the Topaz facility have the lowest water and carbon 

life cycle footprint of any available on the market. And Palo 

Verde may one day have to compete even for the availability 

of wastewater, because the southwestern United States is operating 

in a zero-sum game when it comes to water. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Groundwater Development Project 

Southern Delivery System 

Lake Powell Pipeline Project 

Yampa River Pumpback 

Regional Watershed Supply Project 

(Million Pipeline, Flaming Gorge Pipline) 

Northern Integrated Supply Project 

Cadiz Valley Water Conservation, 

Recovery, and Storage Project 

Bay Delta Conservation Plan 

(Twin Tunnels Project) 

rado River via CAP. Construction of 

the aqueduct began in 1973 and was 

largely complete by 1993, at a cost of 

$3.6 billion. The pipeline uses a series 

of pumps to move water 541 kilometers 

(336 miles) over 915 meters (3,000 

feet) of elevation, traveling from Lake 

Havasu up to Phoenix, and then on 

to Tucson. In a given year, 2.8 million 

megawatt-hours of electricity are 

needed to run CAP and ensure water 

for these two desert cities. The irony 

is that 90 percent of the power comes 

from the Navajo Generating Station. In 

2014, this coal-fired power plant on the 

banks of Lake Powell emitted over 17 

million metric tons of carbon, making 

it one of the top three carbon emitters 

in the United States. Since 24 percent 

of the electricity generated at Navajo is 

used by the pipeline, the carbon footprint 

of this water supply is among the 

highest in the country. And to complete 

the nexus, that plant uses a lot of water. 

The biggest challenge for the West is 

that the region is growing faster than 

most other areas of the United States, 

and climate change is already diminishing 

water supplies. Water managers 

know this fact, and many places are 

considering adaptation strategies that 

include large-scale conveyance systems. 

Taken together, the major projects 

under consideration, and some 

under construction, would move an 

additional 5.4 cubic kilometers of water 

to water-poor areas. What is most 

sobering is that the estimated power 

intensity of many of these projects is 

even larger than the energy footprint 

0 

546 

822 

500 

1,176 

1,000 

1,659 

1,621 

1,459 

1,500 

2,000 

2,500 

3,000 

3,500 

4,000 

gigawatts per cubic kilometer 

3,837 

3,754 

The anticipated gross power intensities for planned water systems in the western United 

States show that water treatment and delivery have the potential to become more energyefficient 

and to emit less carbon. The vertical red line demarcates the net energy used per unit 

water by CAP, one of the nation’s most energy-intensive water supplies. 

of the CAP, but the total amount of water 

delivered is unlikely to be as large. 

Greenhouse emissions drive global 

warming, and that warming increases 

water demand. Water requires energy, 

which produces greenhouse gases. 

And warmer temperatures can also interfere 

with energy production because 

power plants cannot operate optimally. 

We have to find a way to break out of 

this feedback loop. If the Southwest 

and California are to meet future water 

demands by investing in large water 

projects, they certainly ought to consider 

how they are going to power these 

systems. The choices they make will 

affect—one way or another—emissions 

targets and related mitigation policies. 

The Energy–Water Future 

There are unique vulnerabilities that 

emerge for both the energy and water 

sectors when the interconnections between 

the two are considered. These 

issues manifest very differently depending 

on location, and the risks will 

evolve as climate change and population 

growth drive the planet into a 

fundamentally different future. 

There may be no perfect solution 

to these cross-sector issues, one that 

will truly satisfy all perspectives. But 

by understanding the cascading challenges 

and tradeoffs across multiple 

sectors, we have the opportunity to 

optimize our investments by considering 

the broad picture of risks and 

vulnerabilities. Many of us are looking 

at a future that will be hotter and drier, 

with more people and fewer resources 

to go around. But now that we know 

more about how energy, water, and 

climate intersect, we have the opportunity 

to plan, design, and innovate 

for what will be a very different planet. 

We can realize the cobenefits of embracing 

efficiencies in our water and 

energy supplies; we can optimize and 

implement the utility of the future, one 

that integrates management of water, 

energy, and air quality; and we can realize 

the value of our natural resources 

and how they support our way of life. 

Understanding these connections will 

help us to ensure the resilience of the 

entire system—whether it is an ecosystem, 

a city, a nation, or the planet. 

Bibliography 

Averyt, K., A. Huber-Lee, J. Macknick, N. 

Madden, J. Rogers, and S. Tellinghuisen. 

2011. Freshwater Use by U.S. Power Plants: A 

Report of the Energy and Water in a Warming 

World Initiative. Cambridge, MA: Union of 

Concerned Scientists. 

Gleick, P. H. 2015. Impacts of California’s Ongoing 

Drought: Hydroelectricity Generation. 

http://pacinst.org/wp-content/uploads/ 

_________________________ 

sites/21/2015/03/California-Drought-and- 

___________ 

Energy-Final1.pdf. 

Hibbard, K., et al. 2014. Energy, Water, and 

Land Use. Climate Change Impacts in the 

United States: The Third National Climate Assessment, 

eds. J. M. Melillo, T. C. Richmond, 

and G. W. Yohe, pp. 257–281, U.S. Global 

Change Research Program. Published online 

doi:10.7930/JOZ31WJ2. 

Howitt, R., D. MacEwan, J. Medellín- 

Azuara, J. Lund, and D. Sumner. 2015. 

Economic Analysis of the 2015 Drought for 

California Agriculture. Davis, CA: Center 

for Watershed Sciences, University of 

California—Davis. ____________ 

https://watershed. 

ucdavis.edu/files/biblio/Final_ 

_________________________ 

Drought%20Report_08182015_Full_ 

_________________________ 

Report_WithAppendices.pdf. 

_________________ 

Rogers, J., et al. 2013. Water-Smart Power: 

Strengthening the U.S. Electricity System in a 

Warming World. Cambridge, MA: Union of 

Concerned Scientists. 

Skaggs R., et al. 2012. Climate and Energy- 

Water-Land System Interactions, Technical 

Report to the U.S. Department of Energy in 

Support of the National Climate Assessment. 

Richland, WA: Pacific Northwest National 

Laboratory. Pub. no. PNNL 21185. 

Water in the West. 2013. Water and Energy 

Nexus: A Literature Review. Stanford, CA: 

Stanford University. 

For relevant Web links, consult this 

issue of American Scientist Online: 

http://www.americanscientist.org/ 

issues/id.120/past.aspx 


2016 May–June 165 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Paradoxes, Contradictions, 


Many research results define boundaries of what cannot be known, predicted, or 

described. Classifying these limitations shows us the structure of science and reason. 

Noson S. Yanofsky 

Science and technology have 

always amazed us with their 

powers and ability to transform 

our world and our lives. 

However, many results, particularly 

over the past century or so, have demonstrated 

that there are limits to the 

abilities of science. Some of the most 

celebrated ideas in all of science, such 

as aspects of quantum mechanics and 

chaos theory, have implications for 

informing scientists about what cannot 

be done. Researchers have discovered 

boundaries beyond which science 

cannot go and, in a sense, science has 

found its limitations. Although these 

results are found in many different 

fields and areas of science, mathematics, 

and logic, they can be grouped and 

classified into four types of limitations. 

By closely examining these classifications 

and the way that these limitations 

are found, we can learn much 

about the very structure of science. 

Noson S. Yanofsky is a professor of computer and 

information sciences at Brooklyn College of the 

City University of New York. He is a coauthor of 

Quantum Computing for Computer Scientists 

(Cambridge University Press, 2008) and the author 

of The Outer Limits of Reason: What Science, 

Mathematics, and Logic Cannot Tell Us (MIT 

Press, 2013). Email: _______________ 

noson@sci.brooklyn.cuny.edu 

Discovering Limitations 

The various ways that some of these 

limitations are discovered is in itself 

informative. One of the more interesting 

means of discovering a scientific 

limitation is through paradoxes. The 

word paradox is used in various ways 

and has several meanings. For our 

purposes, a paradox is present when 

an assumption is made and then, with 

valid reasoning, a contradiction or falsity 

is derived. We can write this as: 

AssumptionContradiction. 

Because contradictions and falsehoods 

need to be avoided, and because only 

valid reasoning was employed, it must 

be that the assumption was incorrect. 

In a sense, a paradox is a proof that 

the assumption is not a valid part of 

reason. If it were, in fact, a valid part of 

reason, then no contradiction or falsehood 

could have been derived. 

A classic example of a paradox is 

a cute little puzzle called the barber 

paradox. It concerns a small, isolated 

village with a single barber. The village 

has the following strict rule: If you 

cut your own hair, you cannot go to 

the barber, and if you go to the barber, 

you cannot cut your own hair. It is one 

or the other, but not both. Now, pose 

the simple question: Who cuts the barber’s 

hair? If the barber cuts his own 

hair, then he is not permitted to go to 

the barber. But he is the barber! If, on 

the other hand, he goes to the barber, 

then he is cutting his own hair. This 

outcome is a contradiction. We might 

express this paradox as: 

Village with ruleContradiction. 

The resolution to the barber paradox 

is rather simple: The village with this 

strict rule does not exist. It cannot exist 

because it would cause a contradiction. 

There are a lot of ways of getting 

around the rule: The barber could be 

bald, or an itinerant barber could come 

to the village every few months, or the 

wife of the barber could cut the barber’s 

hair. But all these are violations 

of the rule. The main point is that the 

physical universe cannot have such a 

village with such a rule. Such playful 

paradox games may seem superficial, 

but they are transparent ways of exploring 

logical contradictions that can 

exist in the physical world, where disobeying 

the rules is not an option. 

A special type of paradox is called 

a self-referential paradox, which results 

from something referring to itself. The 

classic example of a self-referential 

paradox is the liar paradox. Consider 

the sentence, “This sentence is false.” 

If it is true, then it is false, and if it is 

false, then because it says it is false, it 

is true—a clear contradiction. This paradox 

arises because the sentence refers 

to itself. Whenever there is a system 

in which some of its parts can refer 

to themselves, there will be self-reference. 

These parts might be able to negate 

some aspect of themselves, resulting 

in a contradiction. Mathematics, 

sets, computers, quantum mechanics, 

and several other systems possess 

such self-reference, and hence have associated 

limitations. 

Some of the stranger aspects of 

quantum mechanics can be seen as 

coming from self-reference. For example, 

take the dual nature of light. 

One can perform experiments in which 

light acts like a wave, and others in 

which it acts like a particle. So which 

is it? The answer is that the nature of 

light depends upon which experiment 

is performed. Was a wave experiment 

performed, or was a particle experiment 

performed? This duality ushers 

a whole new dimension into science. 

In classical science, the subject of an 

experiment is a closed system that researchers 

poke and prod in order to determine 

its properties. Now, with quantum 

mechanics, the experiment—and 

more important, the experimenter— 

become part of the system being measured. 

By the act of measuring the 

system, we affect it. If we measure for 

waves, we affect the system so that we 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


In the 1986 movie Labyrinth, the main character is faced with a riddle. 

One door in the scene above leads to her destination, the other to “certain 

death.” She can only ask one of the door guards one question, and 

she’s told that one of them always tells the truth, whereas the other 

always lies. Although she thinks she finds the correct answer, she still 

falls into a trap, likely because the labyrinth itself isn’t fair. Riddles are 

often linked to paradoxes, and our mental constructs, including movies, 

can be full of contradictions. Finding out where such paradoxes exist in 

the real world can help us understand the limits of what science can and 

cannot know. (Image courtesy of the Jim Henson Company.) 

cannot measure for particles and vice 

versa. This outcome is one of the most 

astonishing aspects of modern science. 

The central idea of a paradox is the 

contradiction that is derived. Where 

the contradiction occurs tells us a lot 

about the type of limitation we found. 

The paradox could concern something 

concrete and physical. There are no 

contradictions or falsehoods in the 

physical universe. If something is true, 

it cannot be false, and vice versa. The 

physical universe does not permit contradictions, 

and hence, if a certain assumption 

leads to a contradiction in 

the physical universe, we can conclude 

that the assumption is incorrect. 

Although contradictions and falsehoods 

cannot occur in the physical 

universe, they can occur in our mental 

universe and in our language. Our 

minds are not perfect machines and 

are full of contradictions and falsities. 

We desire contradictory things. We 

want to eat that second piece of cake 

and also to be thin. People in relationships 

simultaneously love and hate 

their partners. People even willfully 

believe false notions. Our language, 

a product of our mind, is also full of 

contradictions. When we meet a contradiction 

in mental and linguistic 

paradoxes, we essentially are able to 

Because science and mathematics are 

constructed to mimic the contradictionfree 

physical universe, they also must 

not contain contradictions. 

ignore it, because it is not so strange to 

our already confused minds. 

We cannot always be so cavalier 

about ignoring contradictions and 


2016 May–June 167 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Rational Assumptions 

One of the oldest stories about a limitation of science 

in classical times concerns the square root of two, 

. In ancient Greece, Pythagoras and his school 

of thought believed that all numbers are whole numbers 

or ratios of two whole numbers, called rational numbers. A 

student of Pythagoras, Hippasus, showed that this view 

of numbers is somewhat limiting and that there are other 

types of numbers. He showed that is not a rational number 

and is, in fact, an irrational number (generally defined as 

any number that cannot be written as a ratio or fraction). 

We do not know how Hippasus showed that the square 

root of two is irrational, but there is a pretty and simple 

geometric proof (attributed to American mathematician 

Stanley Tennenbaum in the 1950s) that is worth pondering. 

The method of proof is called a proof by contradiction, which 

is like a paradox. We are going to assume that the is a 

rational number and then derive a contradiction: 

is a rational numberContradiction. 

From this contradiction we can conclude that is not a 

rational number. 

First, assume that there are two positive whole numbers 

such that their ratio is the square root of two. Let us assume 

that the two smallest such whole numbers are a and b. That 

is, a/b. 

Squaring both sides of this equation gives us 2=a 2 /b 2 . 

Multiplying both sides by b 2 gives us 2b 2 =a 2 . 

From a geometric point of view, this equation means that 

there are two smaller squares whose sides are each of size b, 

b 

a 

a 

and they are exactly the same size as a large square whose 

side is of size a. That is, if we put the two smaller squares 

into the larger square, they will cover the same area. 

But when we actually place the two smaller squares into 

the larger, we find two problems. Firstly, we are missing 

missing 

overlap 

missing 

two corners. Secondly, there is overlap in the middle. So for 

the area of the larger square to equal the areas of the two 

smaller squares, the missing areas must equal the overlap. 

That is, 2(missing)=overlap. 

But wait. We assumed that a and b were the smallest such 

numbers with which this result can happen; now we find 

smaller ones. So this result is a contradiction. There must 

be something wrong with our assumption that a and b are 

whole numbers. And thus the square root of two is not a 

rational number, but is irrational. Hippasus had shown 

that there was a number that did not follow the dictates of 

Pythagoras’s science. 

The followers of Pythagoras were fearful that the conclusion 

of Hippasus would be revealed and people would see the failings 

of the Pythagoras philosophy and religion. Legend has it 

that the other students of Pythagoras took Hippasus out to sea 

and threw him and his irrational ideas overboard. 

falsities in human thought and speech. 

There are times when we must be more 

careful. Science is a human language 

that measures, describes, and predicts 

the physical world. Because science is 

constructed to mimic the contradictionfree 

physical universe, it also must 

not contain contradictions. Similarly, 

in mathematics, which is formulated 

by looking at the physical world, we 

cannot derive any contradictions. If 

we did, it would not be mathematics. 

When a paradox is derived in science 

or mathematics, it cannot be ignored, 

and science and mathematics must reject 

the assumption of the paradox. As 

an example of such a paradox, if we 

assume that the square root of two is a 

rational number, we get a contradiction 

(see box above). In this case, we must 

not ignore the paradox, but rather proclaim 

that the square root of two is not 

a rational number. 

In addition to paradoxes, there are 

other ways of discovering limitations. 

Simply stated, one can piggyback off 

of a given limitation that shows that a 

certain phenomenon cannot occur, to 

show that another, even harder phenomenon 

also cannot occur. A simple 

example: When you are out of shape 

and climb four flights of steps, you 

will huff and puff. We can write this 

activity and its result as: 

Climb four flightsHuff and puff. 

It is also obvious that if someone climbs 

five flights of steps, they also have 

climbed four flights of steps, that is: 

Climb five flightsClimb four flights. 

Combining these two implications 

gives us: 

Climb five flightsClimb four flights 

Huff and puff. 

We conclude with the obvious observation 

that if you huff and puff after 

climbing four flights of steps, you will 

definitely huff and puff after climbing 

five flights of steps. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


In a version of the traveling salesperson problem, 

computer scientist Robert Kosara created 

a map of an estimated best route for U.S. 

presidental candidates to visit all of the nation’s 

ZIP codes. The map uses an approximation 

technique called Hilbert curves, and is 

reported to be about 75 percent optimal. (For 

more on Hilbert curves, see “Crinkly Curves,” 

May–June 2013.) Finding the actual shortest 

route would take a computer essentially an 

infinite amount of time to compute. (Image 

courtesy of Robert Kosara, eagereyes.org.) 

To generalize this simple example, 

assume that a limitation is found 

through a paradox: 

Assumption-AContradiction. 

Thus, Assumption-A is impossible. If 

we further show that: 

Assumption-BAssumption-A, 

we can combine these two implications 

to get: 

Assumption-B Assumption-A 

Contradiction. 

This result shows us that because 

Assumption-A is impossible, then the 

second factor, Assumption-B, is also 

impossible. 

With these methods of finding various 

limitations, we can define the four 

actual classes of limitations. 

Physical Limitations 

The first and most obvious type of limitation 

is one that says certain physical 

objects or processes cannot exist, like 

the village in the barber paradox. 

Another example of a physical process 

that is impossible is time travel 

into the past. This limitation is usually 

The Shortest Route 

The Traveling Salesperson Problem 

is an easily stated computer 

problem that is an example 

of a practical limitation. Consider a 

traveling salesperson who wants to 

find the shortest route, from all possible 

routes, that will visit 10 different 

specified cities. There are many different 

possible routes the salesperson 

can take. There are 10 choices for the 

first city, nine choices for the second 

city, eight choices for the third city, 

and so on, down to two choices for 

the ninth city, and one choice for the 

tenth city. In other words, there are 10 

×9×8×...×2×1=10!=3,628,800 possible 

routes. A computer would have 

to check all these possible routes to 

find the shortest one. Using a modern 

computer, the calculation can be 

done in a couple of seconds. But what 

about going to 100 different cities? A 

computer would have to check 100× 

99×98×...×2×1=100! possible routes, 

which results in a 157-digit-long number: 

93,326,215,443,944,152,681,699,238 

,856,266,700,490,715,968,264,381,621,46 

8,592,963,895,217,599,993,229,915,608,9 

41,463,976,156,518,286,253,697,920,827, 

223,758,251,185,210,916,864,000,000,00 

0,000,000,000,000,000 potential routes. 

For each of these potential routes, the 

computer would have see how long 

the route takes, and then compare all of 

them to find the shortest route. A modern 

computer can check about a million 

routes in a second. That computation 

works out to take 2.9 × 10 142 centuries, a 

long time to find the solution. 

Such a problem will not go away as 

computers get faster and faster. A computer 

10,000 times faster, able to check 

10 billion possible routes in a second, 

will still take 2.9 × 10 138 centuries. Similarly, 

having many computers working 

on the problem will not help too 

much. Physicists tell us that there are 

10 80 particles in the visible universe. 

If every one of those particles were a 

computer working on our problem, it 

would still take 10 62 centuries to solve 

it. The only thing that possibly can 

help this problem is finding a new algorithm 

to figure out the shortest route 

without looking through all the possibilities. 

Alas, researchers have been 

looking for decades for such a magic 

algorithm. They have not found one, 

and most computer scientists believe 

that no such algorithm exists. 

The traveling salesperson problem 

can be solved for small inputs. Even 

for large inputs, a program can be written 

that will solve it, but the program 

will demand an unreasonable amount 

of time to determine the solution. Although 

there does exist a shortest possible 

route, the knowledge of that route 

is inherently beyond our ability to ever 

know, making it a practical limitation. 

(But see image above for a sample of 

one estimate of the answer.) 


2016 May–June 169 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Heritage Image Partnership Ltd/Alamy Stock Photo 

INTERFOTO/Alamy Stock Photo 

Pictorial Press Ltd/Alamy Stock Photo 

Across various fields of science, mathematics, 

and logic, over the past century, some 

of the greatest minds have discovered instances 

in which research cannot find the 

answer, demonstrating a limit on science 

itself. Albert Einstein (top left) showed 

limitations related to relativity theory. Kurt 

Gödel (with Einstein) found that there are 

mathematical statements that are true but 

not provable. Alan Turing (above) showed 

limits to what computers can compute. 

Georg Cantor (far left) showed that not 

all infinite sets are the same size, altering 

the concept of infinity. And Bertrand Russell 

(left) showed a limit in what types of 

mathematical sets can exist, without causing 

a contradiction that cannot be present 

in mathematics. (Albert Einstein and Kurt 

Gödel photograph by Oskar Morgenstern, 

courtesy of The Shelby White and Leon 

Levy Archives Center, Institute for Advanced 

Study, Princeton, NJ.) 

shown through a self-referential paradox 

that is often called the grandfather 

paradox. In it, a person goes back in 

time and kills his bachelor grandfather. 

Thus his father will not be born, 

the time traveler himself will not be 

born—and hence the time traveler will 

not be able to kill his grandfather. One 

need not be homicidal to obtain such 

a paradox: In the 1985 movie Back to 

the Future, the main character starts 

to fade out of existence because he 

traveled back in time and accidentally 

stopped his mother and father from 

getting married. A time traveler need 

only go back several minutes and restrain 

the earlier version of himself 

from getting into the time machine. 

What is different about events in 

time travel that cause these paradoxes? 

Usually, an event affects another, later 

event: If I eat a lot of cake, I will gain 

weight. With the time travel paradox, 

an event affects itself. By killing his 

bachelor grandfather, the time traveler 

ensures that he cannot kill his bachelor 

grandfather. The event negates itself. 

The simple resolution to the grandfather 

paradox is that, in order to avoid 

contradictions, time travel is impossible. 

Alternatively, if perchance time 

travel is possible, it is impossible to 

cause such a contradiction. 

Another example of a limitation that 

shows the impossibility of a physical 

process is the halting problem. Before 

engineers actually built modern 

computers, Alan Turing showed that 

there are limitations to what computers 

can perform. In the 1930s, prior to 

helping the Allies win World War II 

by breaking the Germans’ Enigma 

cryptographic code, he showed what 

computers cannot do by way of a selfreferential 

paradox. As anyone who 

deals with computers knows, sometimes 

a computer “gets stuck” or goes 

into an “infinite loop.” It would be nice 

if there were a computer that could determine 

whether a computer will get 

stuck in an infinite loop. Essentially, 

we are asking computers to be selfreferential. 

Turing showed that no such 

computer could possibly exist. He 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


showed that if such a computer could 

exist, he would make a computer that 

would negate its own “haltingness.” 

Such a program would perform the following 

task: “When asked if I will halt 

or go into an infinite loop, I will give 

the wrong answer.” However, computers 

cannot give wrong answers because 

they do exactly what their instructions 

tell them to do, hence we have a contradiction, 

which occurs because of the 

assumption that we made about a computer 

that can determine whether any 

computer will go into an infinite loop. 

That assumption is incorrect. Many other 

problems in computer science, mathematics, 

and physics are shown to be 

unsolvable by piggybacking off the fact 

that the halting problem is unsolvable. 

There are many other examples of 

physical limitations. For instance, Einstein’s 

special theory of general relativity 

tells us that a physical object cannot 

travel faster than the speed of light. 

And quantum theory tells us that the 

action of individual subatomic particles 

is probabilistic, so no physical 

process can predict how a given subatomic 

particle will act. 

Mental Construct Limitations 

Recall that although our minds are 

full of contradictions, we must, when 

dealing with science and mathematics, 

steer clear of them, and that 

means restricting certain mental and 

linguistic activities. 

In the first years of elementary 

school, we learn an easy mental construct 

limitation: We are not permitted 

to divide by zero. Despite the reasons 

for this rule being so obvious to us now, 

let us justify it. Consider the equation 

3×0=4×0. Both sides of the equation 

are equal to zero and hence the statement 

is true. If you were permitted to 

divide by zero, you could cancel out the 

zeros on both sides of the equation and 

get 3=4. This outcome is a clear falsehood 

that must be avoided. 

A more advanced result in which 

one sees the mental construct limitation 

more clearly is in what’s called Russell’s 

paradox. In the first few years of the 20th 

century, British mathematician Bertrand 

Russell described a paradox that 

shook mathematics to its core. At the 

time, it was believed that all of mathematics 

could be stated in the language 

of sets, which are collections of abstract 

ideas or objects. Sets can also contain 

sets, or even have themselves as an element. 

This idea is not so far-fetched: 

David Parker/Science Photo Library 

A fractal illustration, which is self-similar across length scales and infintely complex, is used to 

illustrate the concept of quantum chromodynamics, the interactions between quarks and gluons, 

which make up protons, neutrons, and other subatomic particles. The forces between quarks and 

gluons are classified as colors—hence the name of the concept. Quantum mechanical properties at 

these subatomic scales are often at the heart of paradoxes and thus limitations on science. 

Consider the set of ideas that are contained 

in this article. That set contains 

itself. The set of all sets that have more 

than three elements contains itself. The 

set of all things that are not red contains 

itself. The fact that sets can contain 

themselves makes the whole subject 

ripe for a self-referential paradox. 

Russell said that we should consider 

all sets that do not contain themselves 

and call that collection R (for Russell). 

Now simply pose the question: Does 

R contain R? If R does contain R, then 

as a member of R that is defined as 

containing only those sets that do not 

The mathematical formulation of 

“This statement is not provable” negates 

its own provability. 

contain themselves, R does not contain 

R. On the other hand, if R does not 

contain itself, then, by definition, it belongs 

in R. Again we arrive at a contradiction. 

The best method of resolving 


2016 May–June 171 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Russell’s paradox is to simply declare 

that the set R does not exist. 

What is wrong with the collection of 

elements we called R? We gave a seemingly 

exact statement of which types 

of objects it contains: “those sets that 

do not contain themselves.” And yet, 

we have declared that this collection is 

not a legitimate set and cannot be used 

in a mathematical discussion. Mathematicians 

are permitted to discuss the 

green apples in my refrigerator but are 

not permitted to discuss the collection 

R. Why? Because the collection R will 

cause us to arrive at a contradiction. 

Mathematicians must restrain themselves 

because we do not want contradictions 

in our mathematics. 

In 1931, Austrian mathematician 

Kurt Gödel, then 25 years old, proved 

one of the most celebrated theorems 

of 20th-century mathematics. Gödel’s 

Incompleteness Theorem shows that 

there are statements in mathematics 

that are true but are not provable. Gödel 

showed this result by demonstrating 

that mathematics can also talk about 

itself. Mathematical statements about 

numbers can be converted into numbers. 

Using this ability to self-reference, 

he formulated a mathematical statement 

that essentially says: “This mathematical 

statement is not provable.” It’s 

a mathematical statement that negates 

its own provability. If you analyze this 

statement carefully, you realize that it 

cannot be false (in which case it would 

be provable), and hence it would be 

true and contradictory. But since it is 

true, it must also be unprovable. Gödel 

showed that not everything that is true 

has a mathematical proof. 

Throughout mathematics and science, 

there are many other examples 

of mental construct limitations. For instance, 

one cannot consider the square 

root of two to be a rational number (see 

box on page 168). Zeno’s famous paradoxes, 

created by Greek mathematician 

Zeno of Elea around 450 bce and involving 

such conundrums as motion 

being an illusion, can also be seen as examples 

of mental construct limitations. 

Practical Limitations 

So far we have seen limitations that 

show it is impossible for something or 

some process (physical or mental) to 

exist. In a practical limitation, we are 

dealing with things that are possible, 

albeit extremely improbable. That is, 

it is impossible to make some prediction 

or find some solution in a normal 

amount of time or with a normal 

amount of resources. 

The classical example is the butterfly 

effect from chaos theory. The 

phrase comes from the title of a 1972 

presentation by mathematician Edward 

Lorenz of the Massachusetts Institute 

of Technology: “Predictability: 

Does the flap of a butterfly’s wings in 

Brazil set off a tornado in Texas?” Lorenz 

was a meteorologist and a mathematician. 

He was discussing the fact 

that weather patterns are extremely 

sensitive to slight changes in the environment. 

A small flap of a butterfly’s 

There are reasons to believe that there 

is a lot more “out there” that we cannot 

know than what we can know. 

wing in Brazil might cause a change 

that causes a change that eventually 

causes a tornado in Texas. Of course, 

one should not go out and kill all the 

butterflies in Brazil; the butterfly flap 

might instead send a coming tornado 

off course and save a Texas city. The 

point of the study is that because there 

is no way we can keep track of the 

many millions of butterflies in Brazil, 

we can never predict the paths of 

tornados or of the weather in general. 

This thought experiment shows a limitation 

of our predictive ability. 

Many other problems from chaos 

theory show limitations. Predicting 

tomorrow’s lottery numbers is also 

beyond our ability. If you wanted to 

know the numbers, you would have 

to keep track of all the atoms in the 

bouncing ball machine—far too many 

for us to ever be able to do. 

Perpetual motion machines are another 

example of a practical limitation. 

Estimating the Unsolvable 

How much is beyond our ability 

to solve? In general, such 

things are hard to measure. 

However, in computer science there is 

an interesting result along these lines. 

We all know of many different tasks 

that computers perform with ease. 

However, there are many problems 

that are beyond the ability of computers. 

We can examine whether there are 

more solvable problems than unsolvable 

problems. 

First, a bit about infinite sets. Mathematicians 

have shown that there are 

different levels of infinity. The smallest 

infinity corresponds to the natural 

numbers: {0, 1, 2, 3 …}. We say that this 

set of numbers is “countably infinite.” 

Although we can never finish counting 

the natural numbers, we can at least 

begin listing them. In contrast, the set 

of all real numbers—that is numbers 

such as –473.4562372... and pi—are 

“uncountably infinite.” We cannot 

even begin to count them. After all, 

what is the first real number after 0? 

0.000001? What about 0.0000000001? 

It can be shown easily that uncountably 

infinite sets are vastly larger than 

countably infinite sets. 

Now let us turn to computers that 

solve problems. There are a countably 

infinite number of potential computer 

programs for solvable computer problems. 

In contrast, there are uncountably 

infinite computer problems. If one takes 

all the uncountably infinite computer 

problems and subtracts the countably 

infinite solvable problems, one is left 

with uncountably infinite unsolvable 

problems. Thus the overwhelming vast 

majority of computer problems cannot 

be solved by any computer. Computers 

can only solve a small fraction of all the 

problems there are. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


There is essentially no way that one 

can make a machine that will continue 

to move without losing all its energy. 

One might be tempted to say that this 

limitation is really a physical one because 

it says that a perpetual motion 

machine cannot exist in the physical 

universe. But by the second law of 

thermodynamics, it is extremely improbable 

for there to be a machine that 

does not dissipate its energy. Improbable, 

but not impossible. 

The theory of thermodynamics and 

statistical mechanics is about large 

groups of atoms and the heat and energy 

they can create. Because in such 

systems there are too many elements to 

keep track of, the laws in such theories 

are given as probabilities, and are ripe 

for finding other examples of practical 

limitations. In computer science, an example 

of a problem that is theoretically 

solvable, but for large inputs will never 

practically be solved, is called the traveling 

salesperson problem (see box on page 

169). There are many more. 

Limitations of Intuition 

The fourth type of limitation is more 

of a problem with the way we look at 

the world. Science has shown that our 

naive intuition about the universe that 

we live in needs to be adjusted. There 

are many aspects of reality that seem 

obvious, but are, in fact, simply false. 

One of the most shocking examples 

of this false perception comes from Einstein’s 

special theory of relativity. The 

notion of space contraction says that if 

you are not moving and you observe an 

object moving near the speed of light, 

then you will see the object shrink. This 

observation is not an optical illusion: 

The object actually shrinks. Similarly, 

the phenomenon of time dilation says 

that when an object moves close to 

the speed of light, all the processes of 

the object will slow down. Of course, 

an observer traveling with the object 

will see neither space contraction nor 

time dilation. Thus our naive view that 

objects have fixed sizes and processes 

have fixed duration is faulty. 

Some of the most counterintuitive 

aspects of modern science occur 

within quantum mechanics. Since the 

beginning of last century, physicists 

have been showing that the subatomic 

world is an extremely strange place. 

In addition to finding that the properties 

of things (such as a photon acting 

like a wave or a particle) depend on 

how they are measured, researchers 

have found that rather than a particle 

having a single position, it can be in 

many places at one time, a property 

called superposition. Indeed, not only 

position, but many other properties 

of a subatomic particle, might have 

many different values at the same 

time. Heisenberg’s uncertainty principle 

tells us that objects do not have 

definitive properties until they are 

measured. A famous concept called 

Bell’s theorem shows us that an action 

here can affect objects across the 

universe, which is called entanglement. 

(For more on Bell’s theorem and entanglement, 

see “Quantum Randomness,” 

July–August 2014.) 

One might think that mathematics 

is always intuitive and that our intuitions 

in that field at least might never 

need to be adjusted. But this assumption 

is also not true. In the late 19th 

century, German mathematician Georg 

Cantor, a pioneer in set theory, showed 

us that our intuition about infinity is 

somewhat troublesome. The naive 

view is that all the infinite sets are the 

same size. Cantor showed that in fact 

there are many different sizes of infinite 

sets. (See box on the opposite page.) 

In the sciences, whenever there is a 

paradigm shift, all of our ideas about 

a certain subject have to be readjusted. 

We have to look at phenomena from a 

new viewpoint. 

The Unknowable 

The classification of the limitations of 

science is only beginning, and many 

questions still arise. Is this classification 

complete, or are there other limitations 

that are of a different type? Is 

there a subclassification of each of the 

classes? How do the methods of finding 

the limitations correspond to the 

types of limitation? Are there results 

that are in more than one classification? 

Because some of the results in the 

other classes might also be counterintuitive, 

there might be some overlap 

between categories. 

How widespread is this inability 

to know? Most scientists work in 

the areas in which progress in knowing 

happens every day. What about 

what cannot be known? In general, 

the concept is hard to measure. There 

are reasons to believe that there is a 

lot more “out there” that we cannot 

know than what we can know. (See box 

on the opposite page for such a calculation 

in computer science.) Nevertheless, 

it is hard to speculate. Isaac Newton 

said, “What we know is a drop, what 

we don’t know is an ocean.” Similarly, 

Princeton University theoretical physicist 

John Archibald Wheeler is quoted 

as saying, “As the island of knowledge 

grows, so does the shore of our ignorance.” 

Newton and Wheeler were 

talking about what we do not know. 

What about what we cannot know? 

Most of the limitations discussed 

here are less than a century old, a very 

short time in the history of science. 

As science progresses, it will become 

more aware of its own boundaries and 

limitations. By looking at these limitations 

from a unified point of view, 

we will be able to compare, contrast, 

and learn about these many different 

phenomena. We can understand more 

about the very nature of science, mathematics, 

computers, and reason. 

Bibliography 

Barrow, J. D. 1999. Impossibility: The Limits of 

Science and the Science of Limits. Oxford: Oxford 

University Press. 

Chaitin, G. 2002. Computers, paradoxes and 

the foundations of mathematics. American 

Scientist 90:164–171. 

Cook. W. J. 2012. In Pursuit of the Traveling 

Salesman: Mathematics and the Limits of Computation. 

Princeton, NJ: Princeton University 

Press. 

Dewdney, A. K. 2004. Beyond Reason: 8 Great 

Problems That Reveal the Limits of Science. 

Hoboken, NJ: Wiley. 

Gbur, G. J. 2016. A glimpse of infinity in the 

swirling of light. AmSci Blogs Macroscope, 

March 9. http://www.americanscientist. 

org/blog/pub/a-glimpse-of-infinity-in- 

____________ 

the-swirling-of-light 

Tavel, M. 2002. Contemporary Physics and the 

Limits of Knowledge. New Brunswick, NJ: 

Rutgers University Press. 

Yanofsky, N. S. 2013. The Outer Limits of Reason: 

What Science, Mathematics, and Logic Cannot 

Tell Us. Cambridge, MA: MIT Press. 






2016 May–June 173 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


The Many Faces of Fool’s Gold 

Pyrite, an iron sulfide, may be worthless to gold miners, but the mineral has 

great utility in everything from fertilizer to electronics. 

David Rickard 

David Rickard is an emeritus professor of geochemistry 

at Cardiff University. This article is 

excerpted and adapted from Pyrite: A Natural 

History of Fool’s Gold by David Rickard, 

with permission from Oxford University 

Press. © Oxford University Press 2016. 

The glittering golden mineral 

pyrite, an iron sulfide (FeS 2 ), is 

known to most people as fool’s 

gold, something that promises 

great value but is intrinsically worthless. 

But pyrite is, has been, and will 

be important to you and the rest of humankind: 

It is the mineral that made 

the modern world. This influence extends 

from human evolution and culture, 

through science and industry, to 

ancient, modern, and future Earth environments, 

and the origins and evolution 

of early life on the planet. 

The role of pyrite in fire-lighting is 

a feature of all ancient civilizations. It 

led to the development of the modern 

chemical, pharmacological, and armament 

industries, in which pyrite continues 

to play a vital role. Even today, 

pyrite is still used in the manufacture 

of sulfuric acid—the most abundantly 

manufactured chemical on the planet. 

The production of medicines based 

on pyrite, such as the alums, paralleled 

the development of the chemical 

industry and can be shown to be the 

origin of Big Pharma, the industrial 

production of medicines. 

Pyrite crystals stand out in nature, 

and the ancients were naturally curious 

as to how these were formed. This led to 

the idea that pyrite formation occurred 

deep within the Earth and the mineral 

was brought to the surface by volcanoes. 

And yet many occurrences of pyrite in 

nature do not appear to be related to volcanism 

at all. Pyrite can be found in soils 

and sediments throughout the Earth as 

myriads of microscopic crystals. This 

pyrite is formed by bacteria that remove 

oxygen from sulfate in the water, producing 

sulfide that reacts with iron to 

form pyrite. More than 90 percent of the 

pyrite on Earth is formed by microbiological 

processes. Bacteria also catalyze 

pyrite’s oxidation and breakdown. 

Pyrite is already playing a significant 

role in frontier areas of science 

and technology, such as nanotechnology 

and energy conversion. The remarkable 

chemical and physical properties 

of this mineral ensure that it will 

continue to do so. Likewise, the widespread 

distribution of huge pyrite concentrations 

throughout both the land 

and the oceans of the Earth will ensure 

that pyrite remains an important 

source of raw materials needed by a 

future 10 billion human beings. 

Crystal Shapes 

The pyrite unit cell, the building block 

of the pyrite crystal, is basically a cubic 

structure. Cubes are also the most 

common pyrite crystal form. The rate of 

growth of the crystal faces is different on 

each face, and square prisms are more 

probable results than perfect cubes. In 

the extreme case this feature may result 

in the formation of pyrite wires. This 

explains the formation of balls of radiating 

pyrite crystals, commonly found 

in limestone and chalk, where they are 

produced from the sulfur and iron in 

groundwater. The individual pyrite 

crystals have simply grown into elongated 

forms that radiate from a center. 

The next most common crystal of pyrite 

is the pentagonal dodecahedron, 

but it turns out not to be regular; the interfacial 

angles are not all 102 degrees. 

Octahedra are the least common natural 

pyrite crystals. And they are not, 

in fact, all perfect: The tips are flattened 

off with cubic faces. The reason for this 

formation was first suggested by the 

great Japanese mineralogist Ichiro Sunagawa 

in 1957, and I further developed 

this theory in 2012. In order for 

a crystal to grow, the concentrations of 

the dissolved constituents must exceed 

the solubility product of the mineral. 

Pyrite is a very insoluble mineral, so 

its solubility product is very low—so 

low that the concentrations of iron and 

sulfur in solution are virtually immeasurable. 

Nucleation is the key here: It 

refers to the first stage of the formation 

of crystals, when atoms and molecules 

initially coalesce. Pyrite will not nucleate 

from solution unless there is 100 billion 

times more iron and sulfur in solution 

than the equilibrium concentration. 

The dodecahedral face requires the 

greatest amount of energy and thus 

tends to be preferred at the highest 

saturations. The octahedral face is the 

next highest, and the most stable cubic 

face the least. So in a situation where 

the supply of nutrients is limited, crystal 

growth depletes the concentration 

of the dissolved components and the 

crystal faces change with time. The octahedral 

crystal will grow until the nutrients 

in solution are used up, and then 

the cubic faces will take over. So most 

octahedra are capped by cube faces. 

My research group designs pyrite 

crystals with various shapes, with applications 

in the Earth and environmental 

sciences and in materials science. 

For example, if we understood what 

controlled the shape of a natural pyrite 

crystal, we would know what the environment 

was like when the crystal was 

formed millions of years ago. 

By varying the concentrations of dissolved 

iron and sulfur, and the hydrodynamics 

of the solution, a vast array of 

forms of pyrite crystals can be produced. 

This explains how a chemically simple 

mineral such as pyrite may exhibit the 

greatest variation in natural crystal 

forms in the mineral kingdom. 

Pyrite Raspberries 

One of the most common forms of 

pyrite in nature is as small, globular 

aggregates of pyrite crystals called 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Pyrite crystals most commonly take on cubic formations; some are smooth (top left), but many are 

striated (top right). Irregular pentagonal dodecahedrons (bottom right) are the crystal form found 

next most often. Octahedrons capped with cubic faces (bottom left) are the least common natural 

crystal shape. (Top left and bottom right images courtesy of the author and Oxford University 

Press; top right, courtesy of J. Murowchick; bottom left, courtesy of Carlos Millan.) 

framboids, because they look like tiny 

raspberries. Pyrite framboids are 

mostly invisible to the naked eye, with 

diameters usually around 0.01 millimeter. 

Framboids are found in rocks, 

especially sediments, of all ages. The 

oldest reported pyrite framboids may 

be from 2.9-billion-year-old sediments 

from South Africa. They are therefore 

extremely stable configurations and 

can last over eons of geologic time. 

The abundance of pyrite framboids is 

quite extraordinary. A guesstimate of the 

total number of framboids in the world 

suggests that there are around 10 30 , 

which is 10 billion times the number of 

sand grains in the world, or about 1 million 

times the number of stars in the universe. 

Today, some 10 12 pyrite framboids 

are being formed every second. 

In the early 20th century, improved 

microscopy showed that these spherules 

consisted of aggregates of pyrite crystals 

less than 0.001 millimeter in size. So each 

framboid may contain more than 1 million 

tiny crystals of pyrite, each of which 

has a similar shape and size. Not only 

that, but they are often beautifully organized 

and arranged in the framboid. 

Detailed studies by my group revealed 

that framboids are not truly 

spherical but have flattened faces. 

They did not grow like normal crystals 

but aggregated together under 

the influence of their surface electrical 

charges. Because these crystals are so 

small, with 50 million of them usually 

needed to make up 1 gram of pyrite, 

these tiny surface electrical forces are 

sufficient to stick the crystals together. 

The Earliest Chemical Industry 

It may not be generally appreciated 

how important pyrite has been and still 

is to the world economy and to providing 

the basics for our current civilization. 

Pyrite continues to be mined 

worldwide and is a major source of 

sulfur, the basic constituent of sulfuric 

acid. Sulfuric acid has become one of 

the most important industrial chemicals, 

and more of it is made each year 

than any other manufactured chemical. 

Sulfuric acid is such an important 

commodity chemical that a nation’s industrial 

strength can be indicated by its 

sulfuric acid production. World produc- 


2016 May–June 175 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


not only the manufacture of a chemical 

substance but also its purification. 

A broken surface of a 5-centimeter diameter pyrite nodule shows radiating pyrite crystals. 

((Unless otherwise indicated, images are courtesy of the author and Oxford University Press.) 

tion in 2004 was about 180 million tons. 

Sulfuric acid is used in the chemical industry 

for production of detergents, synthetic 

resins, dyestuffs, pharmaceuticals, 

petroleum catalysts, insecticides, and antifreeze, 

as well as in various processes 

such as oil-well acidicizing, aluminum 

reduction, paper sizing, and water treatment. 

It is used in the manufacture of 

pigments and includes paints, enamels, 

printing inks, coated fabrics, and paper. 

The list is endless and includes the 

production of explosives, cellophane, 

acetate and viscose textiles, lubricants, 

nonferrous metals, and batteries. 

Sulfuric acid is a relatively recent 

manufactured chemical. Prior to this, 

the important analogous chemical substances 

were the sulfate salts of iron, 

copper, and aluminum, known to the 

ancients as the vitriols. These occurred 

in the lists of minerals compiled by the 

Sumerians 4,000 years ago. They were 

used as mordants in the dyeing industry. 

In order for natural dyes to be fixed 

in the cloth—and not be washed out 

during the next rainy day—it is necessary 

to treat the cloth with a mordant. 

The mordants widely used in dyeing 

were solutions of the vitriols. The demand 

for vitriols could not be satisfied 

from natural supplies, and industries 

developed to manufacture this substance 

from pyrite. It became particularly 

important in late medieval England, 

when much of the nation’s wealth 

was dependent on the wool trade. The 

production of one mordant, pure alum, 

from pyrite has been described as the 

point of origin of the modern chemical 

industry, because the process required 

Pyrite is a major source of sulfur, the basic 

constituent of sulfuric acid, which is one of 

the most important industrial chemicals, 

and made in greater amounts each year 

than any other manufactured chemical. 

Big Pharma 

The manufacture of artificial drugs— 

in contrast to the use of natural 

remedies—can be traced back to pyrite 

and strike-a-lights. It is not a big step 

to drop pyrite from a strike-a-light into 

the fire. The result is the formation of 

sulfur oxide gases with their characteristic 

burnt smell. These sulfur oxide 

gases, apart from being poisonous in 

high doses, can clear clogged-up noses 

and are very useful in fumigation. 

By 300 ce sulfur was being produced 

from pyrite in China’s Shanxi, Hebei, 

Henan, Hunan, and Sichuan provinces. 

One of the earliest descriptions of the 

medicinal use of sulfur was in The Pharmacopeia 

of the Heavenly Husbandsman, 

compiled in the Western Han period (206 

bce–24 ce), which cataloged the medicines 

invented some 3,500 years earlier 

by the legendary emperor Shen Nong. 

Medical sulfur had to be produced 

from pyrite in the absence of deposits of 

natural sulfur. Sulfur was used mainly 

in creams, to alleviate conditions such 

as scabies, ringworm, psoriasis, eczema, 

and acne. The mechanism of action is 

unknown—although sulfur does oxidize 

slowly to sulfurous acid, which in 

turn (through the action of sulfite) acts as 

a mild reducing and antibacterial agent. 

The use of alum in medicine has 

been documented for more than 2,000 

years since the Babylonians listed 

it in one of the first pharmacopeias. 

The main medicinal use of alum was, 

as it still is today, as an astringent to 

improve wound healing. The modern 

styptic used to close up razor nicks 

occurring after wet shaving is alumbased.It 

helps reduce swelling of the 

skin around healing sores. It has also 

been used as an emetic to treat someone 

who has ingested a poison. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Pyrite Feeds the World 

We have seen that pyrite is the 

raw material from which sulfuric 

acid can be made, and 

a major use of sulfuric acid 

in modern economies is in 

the production of fertilizers. 

About 60 percent is currently 

consumed for fertilizer manufacture, 

especially superphosphates, 

ammonium phosphate, 

and ammonium sulfates. 

During the early part of the 

Industrial Revolution, sulfur 

in Europe was sourced from 

natural sulfur deposits associated 

with volcanic fumaroles 

in Sicily. In 1839 the Sicilian deposits 

came into the hands of a 

French company, which raised 

the price threefold. This led to 

other countries reverting to pyrite 

as a source of sulfur. Roasting 

of pyrite produces sulfur 

oxide gases, and these can be 

dissolved in water to produce 

sulfuric acid. Byproducts of the 

process include copper metal from the 

pyrite and an iron-based slag that is 

used in road-building. 

It has been estimated that the population 

of Great Britain was constrained to 

around 6 million in preindustrial times 

due to the limitations of agricultural productivity. 

This compares with more than 

60 million today. The excess 54 million 

people are fed by postindustrial technological 

advances. This step increase 

in agricultural productivity was fueled 

by the development of industrial fertilizers. 

This, in turn, caused a consequent 

exponential increase in the demand for 

sulfuric acid, sulfur, and pyrite. 

Pyrite reserves are distributed 

throughout the world, and known deposits 

have been mined in about 30 

countries. Currently global pyrite production 

is about 14 million tons per 

year, and about 85 percent of this is in 

China. This production is equivalent to 

around 7 million tons of sulfur annually 

with a value of about $160 million. 

This amounts to around 10 percent 

of the total world sulfur production. 

Most of this sulfur is used in sulfuric 

acid manufacture, and most of the sulfuric 

acid is used to make fertilizers. In 

this context, pyrite continues to be a 

major factor in food production. 

Crystal Refraction 

The year 2014 was designated the International 

Year of Crystallography by 

The United Verde massive pyrite deposit in Jerome, AZ, shows 

multicolored rocks resulting from the oxidation of pyrite. For scale, 

the mine entryway at center left is approximately human-sized. 

the General Assembly of the United 

Nations. The reason is that the science 

of crystallography is little appreciated 

by the general public or understood by 

fellow scientists, apart from the crystallographers 

themselves. And yet this science 

has won more Nobel Prizes over 

the past century than any other subdiscipline. 

Of the 136 Nobel Prizes in 

science and medicine that have been 

awarded since 1901, more than 100 

have directly involved crystallography. 

The golden crystals 

of pyrite have played a key role 

in the development of crystallography, 

ultimately permitting 

atoms themselves to be counted, 

imaged, and probed. 

If you look at the surface of 

a CD or DVD disk at an angle, 

you will see a shimmering spectrum 

of colors on the surface of 

the disk as bands of luminous 

greens and blues seem to radiate 

out from the center of the 

disk. The grooves on the disk 

are diffracting the light that is 

being reflected from its silver 

surface. Diffraction occurs 

when a wave encounters an obstacle. 

As the wave hits an object, 

new waves are produced at 

all points along the wave front. 

These waves propagate spherically, 

and thus light can appear 

to bend as it passes an object. If 

there is a narrow slit, light will 

appear to bend around both 

edges of the slit. And if the width of the 

slit approaches the wavelength of the 

light, the light waves emitted from the 

slit edges will either be in phase or out 

of phase: If the diffracted waves are in 

phase (that is, their peaks and troughs 

are coincident), then the resultant intensity 

is increased; if the diffracted waves 

are out of phase, then the peaks are canceled 

out by the troughs and no light 

is seen. In the case of light, the troughs 

A collapsed slope in the Falun mine in Sweden shows the effect of 300 years of oxidation on a 

massive pyrite ore. Sulfate stalactites of iron (green), copper (turquoise), calcium, magnesium, 

zinc, and lead (white) protrude from a mass of iron oxide ocher. The temperature in the mine 

can reach 50 degrees Celsius. (From D. Rickard and R. O. Hallberg, 1973, De Små gruvarbetarna 

i Falun. Svensk Naturvetenskap, pp. 102–107.) 


2016 May–June 177 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


a 

10 micrometers 10 micrometers 

A group of pyrite framboids (a) shows various ordering patterns of the individual pyrite crystals. A closeup 

of a single framboid (b) shows the typical subspherical form and partial ordering of the 0.001-millimeter 

pyrite crystals. (From D. Rickard, 2012, Sulfidic Sediments and Sedimentary Rocks; courtesy of Elsevier.) 

and ridges are represented by a series of 

bands. These depend on the wavelength 

of the incident beam and the density of 

the slits in the object. The diffraction effect 

is seen on the fine grooves of a CD 

disk but not on a grill, for example. In a 

typical diffraction grating, the number 

of slits ranges from a few tens to a few 

thousand per millimeter. Note that because 

there is a relationship between the 

wavelength of light and the slit width, 

each wavelength of the incident beam is 

sent in a slightly different direction. This 

can produce a spectrum of colors from 

white light illumination, visually similar 

to the operation of a glass prism; this is 

the shimmering, multicolored effect on 

the CD surface. The upshot of all this is 

that by measuring the angle of the emitted 

light from a diffraction grating and 

its wavelength, we can calculate the size 

and number of the slits in the grating 

that produced the spectrum. 

In 1912 Max Laue reported that x-rays 

were diffracted by crystals. Laue’s great 

insight was to realize that because x-rays 

have wavelengths similar to that of the 

distances between atoms in crystals, the 

atoms would diffract the x-ray waves, 

producing bands of more and less intense 

x-rays. As with the CD and other diffraction 

gratings, the distances between the 

x-ray bands and their intensities depend 

on the distances between the atoms in the 

crystal. X-rays exited in a pattern determined 

by the atomic structure. 

The technique was seized upon by 

W. H. Bragg and W. L. Bragg. The Braggs 

realized that the angles and wavelength 

of the x-rays diffracted by a crystal 

would be functions of the positions of 

the planes of atoms in the crystal. Because 

there are several such planes in 

any crystal, this would enable the atomic 

structure of the crystal to be computed. 

Pyrite was one of the first crystalline 

materials investigated by the Braggs. 

They used it to demonstrate that x-rays 

A suspension of tiny pyrite crystals might 

be sprayed onto solar panels like paint. 

b 

behaved in the same manner as light 

and not as a series of particles. In 1914, 

W. L. Bragg succeeded in solving the pyrite 

structure and confirmed a theoretical 

mathematical model of pyrite. 

Pyrite helped support the foundations 

of x-ray crystallography, because it 

showed how the method could be used 

to determine the structure of a more 

complex substance. This ultimately led 

to the determination of the structure of 

DNA in 1953 by Francis Crick and James 

Watson, based on Rosalind Franklin’s 

x-ray crystallographic analyses. 

Pyrite and the Electronics Industry 

Pyrite is a semiconductor; that is, it is 

neither a conductor like metal nor an 

insulator like most rocks. Semiconductors 

such as pyrite can switch between 

being a good conductor or 

insulator under the effects 

of electric fields or light, or 

by doping the material with 

traces of impurities. In pyrite, 

only a small amount 

of energy is required to release 

electrons from being 

chained to the atomic nuclei 

so that they can move freely 

in the material and conduct 

electricity. In other words, 

a small amount of energy 

will switch pyrite from behaving 

like an insulator to 

behaving like a conductor. 

Satisfying the increased 

demand for electricity will 

be one of the fundamental 

problems faced by humankind 

over the next 50 years. It is estimated 

that more than 30 million billion 

watts of extra power will be required 

by 2050, and supplying this by fossilfuel 

generation not only is improbable 

but also would have a considerable impact 

on the Earth’s climate. The obvious 

solution is to capture the energy from 

the Sun using solar panels. However, 

current silicon-based solar panels are 

expensive. The energy cost, amortized 

over the 20-year lifetime of the panel, is 

around twice as much as that of windand 

natural gas–generated electricity. 

This is where pyrite comes in as the 

most cost-efficient alternative solar panel 

material to conventional silicon. 

Pyrite absorbs 100 times as much 

light as the present major solar cell material, 

silicon. A thin layer of pyrite, just 

0.1 millionth of a meter in thickness, 

theoretically absorbs almost 90 percent 

of the solar radiation, whereas thicker 

current silicon-based systems harvest 

less than 20 percent. Silicon, although 

it is the second most abundant element 

in the Earth’s crust, is expensive to extract. 

The cost of extraction is about $1.7 

per kilogram, or more than 50 times as 

much as pyrite. Because only a very 

thin layer of pyrite is required to collect 

the sunlight, suspensions of tiny pyrite 

crystals, such as those that constitute 

the ubiquitous pyrite framboids, might 

be mixed in a solvent and sprayed onto 

panels like paint. Considerable research 

is going on worldwide at present to synthesize 

pyrite crystals and films with 

various compositions in order to produce 

an optimal solar energy collector. 

The other way to help resolve the 

world energy gap is to find a better way 

to store electricity. Electric automobiles 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


are wonderful, except for the 

fact that they are at present 

limited to a 100-mile working 

distance and a 24-hour charging 

cycle. Portable computers 

are fantastic—for eight 

hours until the battery runs 

out. Pyrite is a source material 

for sulfuric acid, and one 

use of it is in car batteries: It is 

the acid in the lead-acid battery. 

These lead-acid batteries 

are still used in automobiles, 

even though the technology 

is ancient, because they are 

rechargeable. However, these 

lead-acid batteries are cumbersome 

and not suitable for 

many applications where a 

small solid-state battery is 

required. The problem with 

these small batteries is that 

they are not especially powerful 

or, in many cases, rechargeable. 

There have been 

many recent advances in battery 

technology. One of the most familiar 

is the development of lithium batteries. 

In the Energizer series of lithium batteries, 

lithium metal is the anode (the negative 

electrode), and pyrite is the cathode 

(the positive electrode). This pyrite has 

been ground down to 0.1-millimeter 

particles and stuck on aluminum foil in 

the battery. The battery works by a redox 

reaction whereby the lithium metal is 

oxidized to produce lithium sulfide and 

the pyrite is reduced to iron. The redox 

reaction produces electrons, which we 

use as electricity. The lithium batteries 

are popular because they are relatively 

light, so the amount of energy per gram 

is optimized. At present these basically 

are not rechargeable, and the development 

of rechargeable lithium batteries 

is a major international target of technological 

research. 

Pyrite is an attractive material for 

the electronics industry: It is widely 

distributed, cheap, and readily available. 

It has some environmental 

benefits in terms of the amount of 

energy required in transport and manufacture. 

All of these attributes are the 

same as those that originally placed 

pyrite at the core of early industrial 

development. It is interesting to speculate 

that the 21st century will see the 

burgeoning of a pyrite-driven electronics 

industry, just as earlier periods 

witnessed the development of pyritedriven 

chemical, pharmaceutical, and 

explosives industries. 

A photomicrograph, taken with a blue filter, shows small blebs of 

yellow gold (arrow) within a 0.3-millimeter pyrite crystal. 

Invisible Gold 

A microscopic image, above, shows 

gold occurring as tiny blebs entirely 

enclosed within a pyrite grain. In fact, 

pyrite is often associated with gold. The 

solutions in the Earth that transport 

iron and sulfur to form pyrite are also 

likely to transport other metals, including 

gold. Pyrite is slightly oxidized relative 

to other metal sulfide minerals. The 

slightly more oxidized environment in 

which pyrite precipitates also destroys 

the sulfide complexes that keep the 

gold in solution, and the gold precipitates 

as a metal. For these reasons, most 

gold deposits in the world contain pyrite 

as a more or less abundant mineral. 

In the case of so-called invisible gold, 

tiny precipitated gold particles have 

been trapped in the growing crystal 

of pyrite. The amount of gold within 

the grain shown above is probably 

around 1 percent by weight, because 

gold is about four times as heavy as 

pyrite. A ton of this pyrite would then 

contain around 10,000 grams of gold, 

with a present-day value of more than 

$400,000. It is worth mining if the gold 

can be extracted from within the pyrite. 

Gold dissolves in cyanide solutions, 

and more than 90 percent of gold production 

is based on a cyanide process. 

In some low-grade ores, the crushed 

rock is piled into heaps and sprayed 

with a dilute cyanide solution. After 

about six months the liquor exiting the 

heap carries sufficient gold in solution 

to be collectable. Of course, 

cyanide is highly poisonous, 

and although efforts are 

made to contain and denature 

it, accidents and escapes continue 

to occur. 

One of the problems with 

gold extraction is that much of 

the gold is included within pyrite 

and related minerals. This 

means that chemical leachates, 

such as cyanide, cannot get at 

the gold because it is protected 

by the pyrite. In the past the 

only way to release the gold 

was to roast the pyrite at 700 

degrees Celsius or to digest it 

in strong acid in an autoclave 

at elevated temperatures and 

pressures. Both of these processes 

are very expensive. In 

1986 industrial-scale testing 

of bio-oxidation of refractory 

gold ores was introduced by 

Gencor in South Africa. In 

this process the crushed ores 

are initially subjected to the attention of 

pyrite-oxidizing microorganisms in tank 

fermenters. The process exposes more 

of the gold, and subsequent cyanidation 

of the bio-oxidized concentrates can 

result in increases in gold recovery from 

just 30 percent to more than 95 percent. 

The use of microorganic reactors to prepare 

pyritic gold ores for cyanidation 

has become widespread, and numerous 

mines in South Africa, Australia, and 

North America have various operating 

systems. 

The future of bioleaching of ores 

looks bright as ore grades become 

poorer and metal prices become higher, 

and there is a considerable amount of 

research going on at present into this 

technology. There is particular interest 

in the potential of real in situ bioleaching, 

where the ore deposit is not mined 

but fractured and the leach solutions 

are pumped down. The problem with 

this idea at present is the difficulty in 

recovering the solutions—they tend to 

disappear down fractures in the Earth’s 

crust, never to be seen again. It seems 

that whatever the future of this technology, 

pyrite will be at the heart of it. 






2016 May–June 179 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Scientists’ 

Nightstand 

The Scientists’ Nightstand, 

American Scientist’s bookreview 

section, offers brief 

reviews and other booksrelated 

content. Please see also 

our Scientists’ Nightstand 

e-newsletter, which notes books 

coverage and news from the 

world of science publishing: 

http://amsci.org/nightstand-news 

ALSO IN THIS ISSUE 

RUST: The Longest War. 

By Jonathan Waldman. 

page 182 

A BRIEF HISTORY OF CREATION: 

Science and the Search for the 

Origin of Life. By Bill Mesler and 

H. James Cleaves II. 

page 184 

PROFESSOR ASTRO CAT’S 

ATOMIC ADVENTURE. By 

Dominic Walliman and Ben 

Newman. 

page 187 

Behind the Scenes, 

Between the Lines 

LAB GIRL. Hope Jahren. x + 294 pp. 

Knopf, 2015. $26.95. 

Between the lines of every scientific 

manuscript there’s a story. 

One of my own papers, for example, 

reports that I marked 550 native 

jewelweed plants at the start of 

the study and tracked the survival and 

growth of 394 of them as they competed 

with an invasive species. I don’t 

discuss the fate of the remaining 156 

plants, mown down by a neighbor 

who ignored pink tape, caution flags, 

and a property line. Nor do I mention 

the pair of dogs that burst through 

their electric fence 

to attack me every 

time I measured the 

plants that remained. 

Hope Jahren, a 

geobiologist at the 

University of Hawaii 

at Manoa, was 

not satisfied presenting 

only the pieces 

of her story that 

fit within the constraints 

of a scientific manuscript. In 

the first chapter of her new memoir, 

Lab Girl, she explains that “working in 

a lab for 20 years has left me with two 

stories: the one that I have to write, 

and the one that I want to.” 

So begins Jahren’s behind-thescenes 

tour of science. We join her for 

misadventures and triumphs as she 

sets up three labs and conducts research 

in the Canadian Arctic, Ireland, 

Hawaii, and across the continental 

United States. The purview of a geobiologist 

includes everything from soil 

science and geology to atmospheric 

science and botany. Jahren is game for 

all of it—especially the botany. With 

plants as her focus, she pursues vast 

and varied questions. What was the 

Arctic’s climate like 45 million years 

“It is maddening to me 

that the best scientist 

I’ve ever known has 

no long-term job 

security, and that this 

is mostly my fault.” 

ago? How much nutrition can we 

expect sweet potatoes of the future 

to provide? Throughout her memoir, 

Jahren discusses these far-flung concepts 

engagingly, immersing the reader 

in scientific detail that is both accurate 

and accessible. She deftly explains 

how x-ray diffraction works, how bacteria 

can invade via a patient’s IV, how 

a deep hole can provide clues about 

the climate millions of years ago. 

Beyond tales of the research itself, 

she shares her own experiences of 

growing into a scientist: a childhood 

spent exploring her father’s laboratory 

in a community college in rural Minnesota; 

her first lab job, filling IV bags 

in a hospital basement; the first time 

she discovers something no one else 

had ever known. As Jahren explains to 

her young son, “It takes a long time to 

turn into what you’re 

supposed to be.” 

Like many female 

scientists, Jahren 

discovers that pervasive 

sexism makes 

becoming what she 

is supposed to be 

that much more 

challenging. As a 

graduate student, 

she runs an experiment 

at midnight to avoid a male 

postdoc who seemed “particularly 

menacing toward the odd female 

who stumbled into his orbit.” At 

eight months pregnant, as a professor 

at Johns Hopkins University, Jahren 

is forbidden from entering her own 

lab, ostensibly for liability reasons, 

but possibly because the head of her 

department didn’t like the sight of a 

pregnant woman. She was well aware 

that her pregnancy was an anomaly 

in her department, and she describes 

her concerns about it at the time: “I 

am close to being the first and only 

woman ever awarded tenure in this 

hundred-year-old ivy-draped department…and 

I instinctively know that 

I should hide any weakness that accompanies 

my pregnant state.” But 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


after she nearly faints in front of her 

department head after standing up too 

fast (she’d long had low blood pressure), 

he decides that she will not be 

allowed to return to her own lab until 

after her baby’s birth. Worse yet, 

he delivers this new rule to Jahren’s 

husband, another professor, instead 

of to Jahren herself. Tellingly, during 

the episode itself her department 

head watches her slump into her chair, 

and then he “looks around in puzzlement.” 

Instead of checking on her, as 

one might expect of a colleague, he 

wordlessly “goes into his office and 

closes the door.” 

Jahren doesn’t seem to dwell for 

long, either in her life or in her book, 

on the sexist acts directed at her. She 

promptly returns her focus to research. 

But the pointed examples of 

sexual harassment she shares illustrate 

with painful clarity just how draining 

it is for a female scientist to navigate a 

sexist terrain—sapping energy and diverting 

focus that she could otherwise 

direct to her science. 

Perhaps because she had never seen 

a female scientist in her youth, Jahren 

began her undergraduate studies as a 

literature major. Although she quickly 

switched fields, the knowledge and 

skills she gained from her English 

classes, as well as from reading with 

her lit-major mother, are evident in her 

beautifully crafted prose and in the 

literary references woven throughout 

the memoir. Jahren connects her own 

experiences to the works of Charles 

Dickens, e. e. cummings, and Harper 

Lee—often humorously—with the 

same ease that she describes leaf venation. 

This mingling of the literary and 

the scientific highlights their connections, 

as well as the humanity underlying 

both disciplines. 

The memoir interleaves the personal 

and professional, with chapters 

about Jahren’s experiences typically 

alternating with ones on plant physiology. 

Fascinating plant facts do the 

double work of opening avenues for 

deeper reflection. A section on seed 

establishment leads to a description 

of Jahren’s beginnings as a scientist. A 

segment about plant reproduction— 

where she writes, “Successful plant 

sex may be rare, but when it does happen 

it triggers a supernova of new 

possibilities”—precedes the story of 

how she met her husband. 

Jahren peoples her memoir with a 

cast of vividly described characters. 

In Praise of Simple Physics 

The Science and Mathematics behind 

Everyday Questions 

Paul J. Nahin 

Physics can explain many of the things that we 

commonly encounter. It can tell us why the night is 

dark, what causes the tides, and even how best to catch 

a baseball. With In Praise of Simple Physics, popular 

math and science writer Paul Nahin presents a plethora 

of situations that explore the science and math behind 

the wonders of everyday life. 

Cloth $29.95 

Doing Global Science 

A Guide to Responsible Conduct in the Global 

Research Enterprise 

InterAcademy Partnership 

This concise introductory guide explains the values 

that should inform the responsible conduct of 

scientific research in today’s global setting. Featuring 

accessible discussions and ample real-world scenarios, 

Doing Global Science covers proper conduct, fraud 

and bias, the researcher’s responsibilities to society, 

communication with the public, and much more. 

Cloth $14.95 

The Best Writing on Mathematics 2015 

Edited by Mircea Pitici 

This annual anthology brings together the year’s finest 

mathematics writing from around the world. Featuring 

promising new voices alongside some of the foremost 

names in the field, The Best Writing on Mathematics 

2015 makes available to a wide audience many articles 

not easily found anywhere else. 

Paper $24.95 

The Scientist’s Guide to Writing 

How to Write More Easily and Effectively 

throughout Your Scientific Career 

Stephen B. Heard 

In an accessible, informal tone, The Scientist’s Guide 

to Writing explains essential techniques that students, 

postdoctoral researchers, and early-career scientists need 

to write more clearly, efficiently, and easily. 

Paper $21.95 

See our E-Books at 

press.princeton.edu 

____________ 


2016 May–June 181 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Bill Hagopian, her longtime lab manager 

and friend, is the most richly developed. 

The two meet as students at 

the University of California, Berkeley. 

Jahren, a graduate student, convinces 

her advisor to hire Hagopian, an undergraduate, 

and from then on their 

stories become intertwined. He is a 

quirky guy, a loyal friend, and a loner 

who as a teenager had lived for several 

years in an underground fort. He 

is also a brilliant scientist. 

In telling Hagopian’s story, Jahren 

pays tribute to some of the great, unsung 

heroes of science: the professional 

lab managers and techs. These individuals 

dedicate their lives to science 

but choose to remain 

in supporting 

roles. Without them, 

many successful labs 

would not function. 

Yet their livelihoods 

are often at the mercy 

of the next grant 

cycle. Jahren writes, 

“It is maddening to 

me that the best and 

hardest-working 

scientist I’ve ever 

known has no longterm 

job security, and 

that this is mostly my fault.” She is being 

hard on herself here, as unforgiving 

funding systems that have become the 

norm for university research constrain 

her efforts to provide job security for 

those working in her lab. “As research 

scientists,” she admits, “we will never, 

ever be secure.” 

Scrutinizing her own accountability 

in her friend’s job situation is typical 

of Jahren’s breathtakingly honest 

portrayal of herself. She is unafraid to 

depict herself unflatteringly. She admits, 

for example, to petty workplace 

hoarding, stealing a drill from another 

lab, even though she already had five 

of them and plenty of grant money 

to buy more. Moving at times into 

more emotionally fraught territory, 

she describes how her own mother’s 

lack of affection has left her yearning 

for a mother figure. She writes, “I am 

sick to death of this wound that will 

not close; of how my babyish heart 

mistakes any simple kindness from a 

woman for a breadcrumb trail leading 

to the soft love of a mother or the fond 

approval of a grandmother.” 

Most affectingly, she shares her 

struggle with bipolar disorder in gorgeous, 

harrowing prose. She resists 

“I tried to visualize a 

new environmental 

science based not 

on the world that we 

wanted with plants 

in it, but on a vision 

of the plants’ world 

with us in it.” 

approaching the condition as a diagnostic 

label, instead narrating its 

intermittent but all-encompassing 

episodes in unstinting detail, from 

moments when “this great cosmic 

fire hose bathes you in epiphanies” to 

the crushing aftermath in which “you 

wake to a gray sadness that mutes you 

into a silent, weeping numbness.” As 

painful as these recollections must be, 

she is committed to presenting her experience 

in full, promising the reader 

that as she narrates the years before 

her diagnosis and treatment she’ll 

“keep describing how the world spins 

when mania is as strong and everpresent 

as gravity.” Jahren’s memoir 

presents readers 

with a fully human 

scientist who is both 

flawed and gifted, 

who struggles but 

whose dedication to 

her work encourages 

her to persist. 

Jahren is less successful 

when she 

extends this humanizing 

impulse 

to the plant world, 

frequently anthropomorphizing 

the 

flora she describes. Some cases are 

mild (“A seed knows how to wait”), 

while others are egregious (“Probably 

within just the last 10 million years, 

a plant had a new idea, and instead 

of spreading its leaf out, it shaped it 

into a spine”). At best, personifying 

the plants she studies may help draw 

in some readers, encouraging them to 

care about subjects they might never 

have considered. At worst, the technique 

is distracting and undercuts 

the solid—and fascinating—scientific 

details she presents elsewhere. In the 

end, it suggests missed opportunities 

to share some truly amazing science. 

Is it no less fascinating to consider, for 

example, that evolution could shape 

a leaf into a spine than that a plant 

could come up with the idea to do so? 

Still, Jahren’s anthropomorphic tendency 

isn’t just a poetic flourish. She 

shares much in common with Thoreau, 

who began his gardening experiment 

by asking, “What shall I learn of 

beans or beans of me?” Jahren writes 

that she “tried to visualize a new 

environmental science that was not 

based on the world that we wanted 

with plants in it, but instead based on 

a vision of the plants’ world with us in 

it.” Again and again she puts herself 

in a plant’s place, imagining plants 

caring for one another, wishing for 

things, and feeling surprise and companionship. 

She recognizes that many 

will find her perspective unscientific. 

But with three Fulbright awards, two 

Young Investigator Medals, dozens of 

publications, and the fully constructed 

Stable Isotope Geobiology Laboratories 

under her belt, it’s hard to argue 

that her unique approach to scientific 

research hasn’t been productive. 

At its core, Lab Girl is a book about 

seeing—with the eyes, but also the 

hands and the heart. Jahren begins her 

memoir with this quote from Helen 

Keller: “The more I handled things 

and learned their names and uses, 

the more joyous and confident grew 

my sense of kinship with the rest of 

the world.” She spends the rest of the 

book teaching us that if we just look 

closely enough, we can see the opal 

lattice on a hackberry seed, the depths 

of loyalty in our closest friends, the 

wonder in a single leaf, and what we 

ourselves are supposed to become. 

Carolyn Beans is a DC-based science writer specializing 

in ecology, evolution, and biomedicine. She received 

her PhD in biology from the University of 

Virginia in 2014. Her research focused on the ecological 

and evolutionary effects of an invasive plant 

on a closely related native species. You can find her on 

Twitter: @carolynmbeans. 

No Rust for 

the Weary 

RUST: The Longest War. Jonathan Waldman. 

ix + 290 pp. Simon and Schuster, 

2015. $26.95. 

Those who combat rust for a living 

tend to agree on one point: It 

isn’t exciting. 

In Rust, journalist Jonathan Waldman’s 

absorbing book on oxidation, 

workers in the corrosion business 

treat this claim like a mantra, even 

as their own words and actions contradict 

it. Bhaskar Neogi, the engineer 

responsible for the integrity of 

the Trans-Alaska Pipeline, observes, 

“You can’t be in this business if you’re 

looking for excitement.” This, just 

hours after he drove through a flightcanceling 

snowstorm from Anchorage 

to Valdez to witness a high-tech 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


vulnerability-sensing robot 

finish the last leg of its roller-coaster 

journey through 

the full length of the 800- 

mile pipeline. 

John Carmona, proprietor 

of the Rust Store, contributes 

more cognitive dissonance. 

“Our products don’t make 

Christmas lists,” he says. “A 

gallon of rust remover isn’t 

necessarily exciting.” Yet his 

business, which he started 

in 2005, expanded steadily 

throughout the Great Recession. 

His inventory once 

took up two shelves in his 

garage; today it occupies a 

10,000-square-foot warehouse. 

Over the years he’s 

become a kind of Dear Abby 

of rust, fielding a continual 

stream of inquiries—from 

the peacemaking spouse 

fretting over offending rust 

stains to a caller trying to 

eradicate staining at the stadium 

where the Indianapolis 

Colts play. 

Then there is Dan Dunmire, 

head of the U.S. Department 

of Defense’s Office 

of Corrosion Policy and 

Oversight, who insists, “Corrosion’s 

not a sexy topic.” Yet 

he brings a singular energy 

to combating corrosion— 

“the pervasive menace,” as 

he calls it—enthusing, “My 

job is to make boring things fun.” 

His work has sent him around the 

globe, and he has won the admiration 

of NATO colleagues who base their 

practices on his, using a model they’ve 

named after him. The corrosion business 

opened the door for him to collaborate 

with one of his idols, actor 

LeVar Burton, on a series of training 

videos. What’s more, the U.S. Government 

Accountability Office has estimated 

that Dunmire’s projects average 

a 50-to-1 return on investment, 

shaming many a high-tech startup. 

The experts seem prepared to fade 

into the background, yet the importance 

of their work is conspicuous— 

much like rust itself. 

Happily, Waldman ignored his subjects’ 

warnings about the topic’s potentially 

soporific effect and forged 

ahead, yielding an entertaining book 

crammed with fascinating tidbits 

and essential information. The World 

Architectural historian Isabel Hill examines the Statue of Liberty 

in 1985. Before the landmark’s 1986 centennial celebration, it underwent 

a major restoration that dealt with decades of unfettered 

corrosion. “No other rust battle in America,” says author Jonathan 

Waldman, “has been fought so visibly, contentiously, or been celebrated 

so grandly.” From Rust. 

Corrosion Organization estimates 

the global annual cost of corrosion at 

$2.2 trillion, more than 3 percent of 

gross domestic product worldwide. 

The group states that this figure includes 

only corrosion’s direct costs, 

“essentially materials, equipment, and 

services involved with repair, maintenance, 

and replacement” of corrosion’s 

usual suspects, such as pipelines, 

bridges, vehicles, water mains, 

and sewer pipes. Not included, the organization 

notes, is the cost of “environmental 

damage, waste of resources, 

loss of production, or personal 

injury resulting from corrosion.” Nearly 

every organization, whether public 

or private, contends with corrosion. 

Waldman notes that “only a small 

portion of Fortune 500 companies— 

those in finance, insurance, or 

banking—are privileged enough not 

to overtly deal with corrosion.” For 

even these fortunate few, “corrosion 

is a major concern where their 

servers are stored.” 

Most chapters focus on a 

particular aspect of corrosion 

(such as the chemistry 

involved or corrosion’s aesthetic 

potential) or on a related 

area of engineering (food and 

beverage canning, oil pipeline 

maintenance, galvanizing, 

or the development of stainless 

steel). Waldman proves a 

shrewd storyteller. My unscientific 

tests suggest he devised 

a specialized mixture, like a secret 

recipe for addressing corrosion: 

four parts research and 

legwork, three parts characterization, 

one part humor, and 

one part philosophy. He has a 

knack for suspense too, especially 

evident in his narrative 

of the massive public-private 

effort to restore the Statue of 

Liberty and his play-by-play 

account of the 2013 Trans- 

Alaska Pipeline inspection. 

While reading the pipeline 

chapter I struggled not to peek 

at its close, something I rarely 

feel tempted to do. 

The massive amount of research 

Waldman must have 

undertaken to spin the marvelously 

immersive tales 

throughout the book is evident 

in Rust’s wealth of historical 

details. The story of 

the 2013 Alaskan pipeline inspection 

winds its way through the 

history of that particular pipeline 

and through much of the history of 

oil transferal more generally. Constructing 

the narrative for this chapter 

and several others—the one on the 

massive Statue of Liberty renovation 

project, for example, and another on 

the founding and activities of the 

DOD’s corrosion office—must have 

required a mind-boggling number of 

hours digging through government 

records and corporate papers. (That 

said, I shouldn’t have to speculate 

about this facet of the work. Two 

pages of acknowledgments provide 

a broad sense of Waldman’s sources 

and methods, but the lack of a notes 

section was disappointing.) Waldman’s 

research also provides fodder 

for plenty of nifty historical asides. 

Among them, he offers up the first 

recorded mention of rust, by a Roman 

general who lamented that his troops’ 


2016 May–June 183 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


catapults were so corroded they were 

“causing more casualties in our own 

army than to the enemy.” 

For all the time Waldman logged 

in libraries and archives, as well as 

the frequent-flyer miles he must have 

racked up, the corrosion professionals 

who populate his book steal the 

show. Waldman is an acute observer, 

and he paints vibrant portraits of the 

specialists he shadowed. Extended 

segments focusing on Dunmire and 

Neogi as well as on Alyssha Eve Csük 

(an artist Waldman describes as possibly 

“the only person who makes a 

living finding beauty in rust”) read a 

bit like The Lives of 

the Corrosion Saints. 

His admiration 

fizzes just below 

the surface as he describes 

Csük photographing 

a massive, 

decaying Bethlehem 

Steel Works blast furnace: 

“Over the next 

five hours, I watched 

Csük wander around 

a mazelike industrial complex of greater 

entropic value than a sub-Saharan 

market, calmly and boldly, without a 

map, in search of aesthetic minutiae 

that most people miss entirely.” 

He notes occasional points of friction 

as well. When he presses Dunmire—who 

by all accounts, Waldman 

admits, handles his office’s funding responsibly—about 

the cost of producing 

his training videos, the ebullient, 

eccentric, Star Trek megafan and DOD 

bureaucrat grows testy. He grouches 

about the difficulty of isolating a figure, 

given the structure of the budget 

the videos share with related projects, 

and reminds Waldman how carefully 

he’s had to manage his team’s funds, 

modest by DOD standards, adding, 

“I’m a frugal sonofabitch.” 

Corrosion specialists, it turns out, 

tend to be passionate about their 

work, however tedious they claim it 

to be. Each has a vision, and none is 

easily deterred. Some are true evangelists. 

Waldman argues that Harry 

Brearley, acknowledged as the father 

of stainless steel, is credited with the 

invention partly because he persisted 

in sharing his creation with anyone 

who would listen, until others began 

believing in its value as much as he 

did: “If anything, it was this tenacity— 

this quasi -insanity—that set him apart 

from earlier discoverers.” 

The World Corrosion 

Organization 

estimates the 

global annual cost 

of corrosion to be 

$2.2 trillion. 

As for Dunmire, his corrosionbattling 

passion is rooted in his concepts 

of service and responsibility. He 

repeatedly pushes his physical limits, 

maintaining an exhausting schedule to 

be sure he’s doing everything he can 

to “fight the good fight,” as he puts it, 

against corrosion—ultimately to ensure 

those serving in the military have 

equipment, infrastructure, vehicles, 

and facilities that are safe, durable, 

and reliable. Once a soldier himself, 

Dunmire is single-minded about his 

mission. “I’ll do anything for the warrior,” 

he says. “Without the warrior,” 

he adds, “We don’t have a country. 

Any discomfort that 

comes up, when you 

think about people 

giving up life and 

limb for this country, 

…I’ll put up with 

any bureaucratic 

bullshit anyone puts 

in front of me.” 

Waldman rounds 

out Rust’s colorfully 

peopled landscape 

with philosophical and lighthearted 

touches. Late in the book, he draws 

parallels between Neogi’s meticulous 

approach to pipeline integrity and 

the obsessive way the engineer cares 

for his beloved tropical fish. His pets 

occupy a 2,400-gallon tank tricked 

out with motion sensors, video camera 

monitors, two sources of backup 

power, and any number of devices that 

measure everything from dissolved 

oxygen to specific gravity. Each hour, 

20,000 gallons of water flow through 

the tank, passing through filters Neogi 

built himself, which reside in a closet 

he converted into a custom-ventilated 

control room. A separate tank of coral 

further purifies the water. As Waldman 

observes, Neogi “has built a miniature 

simulacrum of a triple-redundant failsafe 

pump station in his basement.” 

Just when Waldman has made the 

case that rust is scientifically, economically, 

and artistically important, he 

throws the reader a curve and argues 

that rust is morally important too. 

Carmona, the pensive Rust Store proprietor, 

alludes to it: “There’s a subset 

of society that says, ‘Hey, what I’ve got 

is pretty good, and I’m going to maintain 

it.’ I think that attitude is what led 

me to open the store. I wanted to fix 

things up.” The people at the heart of 

these stories remind us to resist the enticements 

of a throwaway culture and 

to care about and attend to what surrounds 

us. “Dealing with rust,” Waldman 

says, “should give us a little more 

respect for what’s public, a little more 

regard for the future.” 

Dianne Timblin is the book review editor for American 

Scientist. Find her on Twitter: @diannetimblin. 

On the Origin of 

Origin Stories 

A BRIEF HISTORY OF CREATION: Science 

and the Search for the Origin of Life. Bill 

Mesler and H. James Cleaves II. 336 pp. 

W. W. Norton, 2015. $27.95. 

An argument can be made that 

three of the most exciting 

weeks in 20th-century science 

occurred between April 25 and May 

15 of 1953. On the former date, James 

Watson and Francis Crick published 

a brief note in Nature titled “Molecular 

Structure of Deoxypentose Nucleic 

Acids.” Two weeks and six days later 

Stanley Miller published—in the 

equally prestigious Science—a similarly 

brief note titled “A Production of 

Amino Acids Under Possible Primitive 

Earth Conditions.” Neither title is, on 

its face, attention-grabbing. Such is the 

understated culture of science. 

But in the span of those three 

weeks, the two publications revolutionized 

our understanding of who 

we are and whence we came: The first 

piece described the structure of DNA, 

and the second discussed conditions 

under which proteinlike molecules 

could arise from a soup of wholly unproteinlike 

precursors. While Crick 

and Watson’s paper has come to be the 

more famous, Miller’s paper drew far 

more attention at the time. Although 

Crick and Watson explained the fundamental 

structure of life—DNA— 

Miller directly tackled the question of 

the origin of life itself. And origin stories, 

as we know, are some of the most 

powerful stories there are. 

In A Brief History of Creation, Bill 

Mesler and H. James Cleaves II trace 

humanity’s fascination—obsession, 

really—with the origin story of life on 

Earth as Westerners have told it, from 

the philosophy of Anaximander in 

the 6th century BCE to a 21st-century 

genetic and chemical biology laboratory 

at Harvard Medical School. The 

authors’ pace is brisk as they dip into 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


THE MIT PRESS 

TURING’S VISION 

The Birth of Computer Science 

Chris Bernhardt 

“A fascinating account of Alan 

Turing’s epic research paper, 

which kicked off the entire 

computer revolution. I’m 

particularly impressed by the 

amount of detail the author 

includes while keeping everything 

simple, transparent, and 

a pleasure to read.” 

—Ian Stewart, author of 

In Pursuit of the Unknown: 

17 Equations That Changed 

the World 

CREATING LANGUAGE 

Integrating Evolution, 

Acquisition, and Processing 

Morten H. Christiansen 

and Nick Chater 

foreword by Peter W. Culicover 

A work that reveals the profound 

links between the evolution, 

acquisition, and processing 

of language, and proposes a 

new integrative framework for 

the language sciences. 

INVENTING ATMOSPHERIC 

SCIENCE 

Bjerknes, Rossby, Wexler, 

and the Foundations 

of Modern Meteorology 

James Rodger Fleming 

“James Fleming uncovers 

the rich history of modern 

meteorology by finding amazing 

new sources of information 

on Vilhelm Bjerknes, Carl 

Rossby, and Harry Wexler, three 

giants in this field. These three 

scientists led the charge for 

breakthroughs in atmospheric 

science, numerical weather 

prediction and climate simulation, 

and new observational 

systems. This book is very 

reader friendly and is highly 

recommended.” 

—Warren M. Washington, 

Senior Scientist, The National 

Center for Atmospheric Research 

THE HUMAN ADVANTAGE 

A New Understanding of How 

Our Brain Became Remarkable 

Suzana Herculano-Houzel 

“Elephants have bigger brains 

than humans. So why are 

we more intelligent? Suzana 

Herculano-Houzel tells how 

her ability to count neurons 

gives us a radical new understanding 

of brain biology. Her 

science is convincing, fun, and 

inspiring. The Human Advantage 

is a game-changer.” 

—Richard Wrangham, 

author of Catching Fire: How 

Cooking Made Us Human 

ANCIENT ORIGINS 

OF CONSCIOUSNESS 

How the Brain Created 

Experience 

Todd E. Feinberg 

and Jon M. Mallatt 

“A very level-headed, deeply 

informed, and magisterial 

approach to the neurobiological 

basis of consciousness 

that considers the evolutionary 

history, the neuroanatomy, 

and the behavior of extant 

animals. The book casts a wide 

net and pinpoints the origin 

of consciousness to the time 

of the Cambrian explosion.” 

—Christof Koch, author of 

Consciousness: Confessions of 

a Romantic Reductionist 

mitpress.mit.edu 

____________________ 


2016 May–June 185 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


and out of the current of history just 

often and briefly enough to make it 

through roughly 2,500 years of philosophical 

and scientific musings. Although 

the underlying thread of life’s 

origins is there to knit the whole together, 

here and there the narrative 

reads like a series of appended biographies. 

Few scientific luminaries—from 

Egyptian mathematician and Neoplatonist 

Hypatia to groundbreaking 

17th-century experimental biologist 

Francesco Redi to physicist, biochemist, 

and 1980 Nobel laureate Walter 

Gilbert—escape mention in this telling, 

and the overwhelming impression one 

gleans from the book is that an impressive 

number of great scientists, at one 

point or another in their careers, have 

become obsessed with the question of 

the origin of life. 

The authors’ own passion for the 

subject is evident in this broad-based, 

colorfully narrated account. Cleaves, 

an associate professor of geochemistry 

at the Tokyo Institute of Technology 

Earth-Life Science Institute, and 

Mesler, a journalist, combine their 

faculties to offer lucid descriptions of 

complicated research. Cleaves’s scientific 

career has been devoted to investigating 

the enigma that drives this 

book: the beginning of life on Earth. 

Not only has he published extensively 

on prebiotic chemistry, the science 

of compounds that existed on Earth 

before the formation of life, but he 

has also coauthored several scholarly 

works with Miller himself. 

It’s no surprise, really, this age-old 

impulse to discover the beginning of 

things. As this book shows, throughout 

the history of biology it has never 

been far from center. Louis Pasteur, 

Antonie van Leeuwenhoek, Charles 

Darwin, and Crick, among others less 

well-known, all turned their gaze to 

life’s origin. The arguments of—and 

between—these great thinkers often 

centered on what, exactly, constitutes 

life, and therefore what might constitute 

its formation. 

When Darwin published On the Origin 

of Species in 1859 (after being spurred 

to do so by Alfred Russel Wallace’s impending 

publication of essentially the 

same theory), it did not take long for 

readers to appropriate its logic on the 

origin of species to explain the origin 

of life itself. Darwin at first was reluctant 

to speculate on the ultimate origins 

of life, employing some of Origin’s 

(continued on page 188) 

Adventures of a Spacefaring Feline 

On Earth, cats aren’t exactly considered team players. Nor are they 

viewed as especially nerdy. (I mean, they’re not exactly owls, 

right?) Sure, they’re cool with a 15-hour nap or a frenzied midnight 

sprint around the house. But coteaching science lessons— 

with a mouse? I think not. 

Space cats are different. 

In 2013, author Dominic Walliman, who has a doctorate in quantum device 

physics, teamed up with illustrator and comic book creator Ben Newman 

to introduce to the creatures of Earth an intrepid cosmic traveler in Professor 

Astro Cat’s Frontiers of Space (Flying Eye, $24.00). A big, bold book geared 

for humans ages 7–11 (or anyone up to approximately 78 years north of those 

ages), Frontiers of Space welcomes readers into its pages with gorgeous retroinspired 

artwork and keeps them there by describing the wonders of the 

universe and the science underlying them. Amid the facts about telescopes, 

the death of stars, and the speed of light, Professor Astro Cat and his spirited 

companion, Astro Mouse, keep up a witty patter. 

The two have been keeping their creators busy. Professor Astro Cat’s Solar 

System (Minilab Studios, $2.99, iOS and Android), a mobile app adapted from 

a portion of Frontiers of Space, appeared in 2015. 

And—to fans’ great delight—the next book, Professor Astro Cat’s Atomic 

Adventure (Flying Eye, $24.00), is set for a May release. 

For those who enjoyed the first book, Atomic Adventure will not disappoint. 

The artwork is just as dazzling, created with a similar, brighter palette 

and again adopting shapes and flourishes that evoke 1960s space-age 

designs. The science is just as fascinating too, and it’s presented even more 

thoughtfully on the page, with a bit more airiness that helps guide the eye 

from one discovery to the next. Atomic Adventure presents a more broadbased 

view of physics, covering topics such as the scientific method, measurement, 

atoms and molecules, Newton’s laws, energy, electricity, magnetism, 

and dark matter. Even the multiverse gets a nod. A section on the science 

of light is especially delightful, presenting Astro Cat in artist garb, painting 

away as he answers a classic query (“Why is the sky blue?”) and then goes on 

to explain the electromagnetic spectrum. Considering the breadth of physics 

covered in Atomic Adventure, kids may find it a more natural starting place 

before going into the astrophysics of Frontiers of Space, but starting with 

either book should be fine. 

Whether you’re a cat connoisseur, a dog devotee, a hamster partisan, or 

an iguana booster, you’re apt to agree that the affable, amusing, and—yes— 

wonderfully nerdy Professor Astro Cat makes a fine companion for the budding 

scientist. —Dianne Timblin 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Professor Astro Cat’s Atomic Adventure introduces kids to a wide 

range of physics’ basic concepts, such as the properties of light 

(opposite page), pressure (left), and magnetism (below, right). From 

Professor Astro Cat’s Atomic Adventure. 

Through handy diagrams and seasonally appropriate attire, Professor 

Astro Cat and Astro Mouse explain what causes the Earth’s 

seasons as well as some of their effects (bottom of page). From the 

app Professor Astro Cat’s Solar System. 


2016 May–June 187 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


Wikimedia Commons 

This 1882 cartoon from Punch’s Almanack puckishly suggests that “man is but a worm” as it 

speculates about the evolutionary path that produced a life form native to England, the dapper 

Victorian gentleman. Reactions to On the Origin of Species were mostly critical at first, even 

among scholars, authors Bill Mesler and H. James Cleaves II explain, but “the strength of Darwin’s 

arguments gradually won over the scientific community.” From A Brief History of Creation. 

most famously lyrical—and least scientific—language: 

“There is grandeur 

in this view of life,” he wrote, “with its 

several powers, having been originally 

breathed into a few forms or into one; and 

that, whilst this planet has gone circling 

on according to the fixed law of gravity, 

from so simple a beginning endless 

forms most beautiful and most wonderful 

have been, and are being evolved” 

[emphasis added]. 

Later he regretted somewhat the biblical 

tone he had taken in Origin, and 

he speculated more boldly about the 

details of life’s ultimate origin, writing 

to his friend and fellow scientist Joseph 

Hooker more than a decade after Origin’s 

publication that perhaps life had 

originated in “some warm little pond 

with all sorts of ammonia and phosphoric 

salts, light, heat, electricity, &c. 

present, that a proteine [sic] compound 

was chemically formed, ready to undergo 

still more complex changes.” 

The final chapters of A Brief History 

of Creation delve into current theories 

about what exactly happened in that 

“warm little pond.” The theories generally 

involve RNA, the molecule that, 

in the governing dogma of biology, is 

responsible for the translation of the 

DNA genetic code into the operable 

machinery of proteins. But in a discovery 

that netted them the 1989 Nobel 

Prize in chemistry, Sidney Altman and 

Thomas Cech showed that RNA could 

bridge the gap between information 

storage and proteinlike functionality. 

This finding meant that, as the Royal 

Swedish Academy of Sciences noted 

in its award statement, “RNA…is not 

only a molecule of heredity but also 

can function as a biocatalyst.” This discovery, 

as Mesler and Cleaves point 

out, helped resolve a chicken-or-egg 

debate among scientists who studied 

the origins of life, bridging the 

“metabolism-first” group, who “saw 

the protein or something like it as the 

earliest key component of life,” and the 

“gene-first” group, who thought “that 

the development of DNA and of genetic 

machinery was the likely first step.” 

The history of researching the origin 

of life has been one of dramatic 

progress, if mainly of the opportunistic 

sort: The book shows that as fundamental 

discoveries are made, they are 

used to refine the existing picture. But 

as we hone our knowledge of the basic 

biology involved, we confront an underlying 

and quite possibly insuperable 

quandary. As Mesler and Cleaves 

write, “It will be the same dilemma 

embodied by the question once posed 

by the physicist Enrico Fermi to his old 

friend Harold Urey: Is this how it could 

have happened, or how it did happen?” 

Indeed, science fundamentally 

describes the way nature does, not how 

it did, and a theory of life’s origins will 

never be able to tell us with certainty 

what happened in that “warm little 

pond” nor, for that matter, whether the 

pond existed at all. 

Even so, beyond the scientific benefits 

of refining our understanding of 

how life might have arisen, research 

into the origins of life may have philosophical 

repercussions. As the authors 

write about Francis Crick’s funeral: 

“Michael Crick said that his father had 

wanted to be remembered for finally 

putting to rest the theory of vitalism, 

the idea that some uncrossable chasm 

existed between the living and nonliving. 

Noting that the word ‘vitalism’ was 

not recognized by Microsoft Word, he 

said, ‘Score one for Francis.’” Considering 

that Francis Crick shared responsibility 

for one of the greatest fundamental 

discoveries in human biology, 

it is remarkable that he considered his 

utmost achievement to be the final refutation 

of vitalism. Crick saw that describing 

the double helix was not just a 

necessary step toward understanding 

biological processes for their own sake, 

but a step toward connecting the living 

and the nonliving, and placing humanity, 

and all life, in its proper relation to 

the rest of the universe. 

Ryan Seals is a postdoctoral research fellow at the Harvard 

T. H. Chan School of Public Health in Boston, 

Massachusetts. His research focuses on the epidemiology 

of neurodegenerative disease. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


May–June 2016 

Volume 25 

Number 3 

Sigma Xi T day 

A NEWSLETTER OF SIGMA XI, THE SCIENTIFIC RESEARCH SOCIETY 

Stay in Touch with 

the Society 

Are you a Sigma Xi member who recently 

moved, graduated, or changed jobs? 

If Sigma Xi doesn’t have your up-to-date 

contact information, you are not getting 

the most from your membership. Luckily, 

updating your profile information is 

quick and easy if you follow these steps. 

1. Go to www.sigmaxi.org and click 

“Login” in the top-right corner. If 

you haven’t created a password, 

click “Forgot Your Password”on the 

next screen. Then enter the email address 

that Sigma Xi currently has on 

file for you and follow the steps to 

create a password. 

2. Once logged in, click on your name 

in the top-right corner. Select “My 

Sigma Xi” from the drop-down 

menu. 

3. On the My Sigma Xi page, under 

the Self-Service section, 

select “Update Profile Information.” 

4. Update your address, phone number, 

and email address. The Society 

prefers a nonwork and nonschool 

email address. 

Benefits of updating your profile 

Updated member profiles strengthen 

the value of the Sigma Xi network. Additionally, 

if you’re an active member, 

a current mailing address ensures you 

receive American Scientist. A print subscription 

is included in the cost of annual 

dues or life membership, unless 

you opt into receiving digital editions. 

Active members also have access 

to Sigma Xi’s online member community, 

The Lab: Members to Members, 

and receive a daily email digest if new 

posts are published. Plus, members receive 

an e-newsletter every other week 

with news about programs, members 

and chapters, volunteer opportunities, 

and meetings. If you aren’t receiving 

these emails, check your spam folder. 

Follow Sigma Xi on Facebook at 

___________________________ 

https://www.facebook.com/SigmaXi 

and Twitter at @SigmaXiSociety for 

the latest updates. 


From the President 

The Critical Role of Sigma Xi Members 

As I look at Sigma Xi now, at the end of my year as 

president, I realize that every member needs a 

reason for joining and remaining active in Sigma 

Xi. We need a reason for paying dues each year 

and nominating new members. What is yours? For 

many the answer is American Scientist, and that’s a 

great reason, but there are many more. One is that 

Sigma Xi fosters a culture in which science and engineering 

are prized as the path to discovery and 

to improving the human condition and the condition 

of our world. 

President Mark E. Peeples 

The insights we gain from science and engineering research enhance decision 

making, increasing the likelihood of success and enabling solutions 

to be implemented more quickly. In a world where science and engineering 

are prized, support for the next discoveries would increase. We need to 

encourage public understanding of what is known, the scientific method, 

and the results it produces. We need public support for our work. 

Sigma Xi chapters can be found in many communities and we cross all 

science and engineering disciplines. Our chapters can reach the public in 

a local way to discuss new discoveries and possible solutions to important 

problems. We can reach students, encouraging them to consider science 

or engineering careers. And once they do, we can help them reach their 

maximum potential through our Grants-in-Aid of Research program and 

student-focused events. New problems, such as the current Zika virus threat, 

will require new discoveries and new solutions. We need new scientists. 

I am more committed than ever to Sigma Xi’s role in honoring student 

and faculty scientists, providing them opportunities to enhance their 

careers, and enabling them to reach out to the public. I want to thank all 

of you for your support this year. For my part, I will continue working to 

strengthen our chapters through Sigma Xi Succeeds, an initiative to collect 

the best practices from chapters so that our membership team at headquarters 

can provide them to you when you need them, in a streamlined, 

simple-to-use form. Please contribute your chapter’s successes by logging 

in to SigmaXi.org. Go to “Chapters” and select “Officer Resource Center” 

from the drop-down menu to find Sigma Xi Succeeds. 

I am proud that as a Society, Sigma Xi is now much stronger than it was 

two years ago, primarily through the efforts of past president George Atkinson 

to move our headquarters to more suitable, less expensive space. In addition, 

our interim executive director, John Nemeth, has initiated important 

improvements and collaborations that will bear fruit in the next year or so, 

and he is leading the charge to identify the ideal, permanent executive director 

who will continue the rise of Sigma Xi. 

Finally, I would ask you to continue your support of Sigma Xi. Sigma Xi is 

Scientists Supporting Science. Let’s all work to make this more true each year. 

2016 May–June 189 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


PREPARING STUDENTS FOR STEM 

A Project to Inspire Student Interest in Science and Math 

Sigma Xi member Allen Fuhs is 

retired from his job as a professor, 

but he still wants to teach. He has 

an idea to inspire students around 

the United States about science and 

math by putting a geometry-based 

activity on the back of cereal boxes. 

“We can reach a million students, 

parents, and teachers,” he said. 

Fuhs brought his idea, and a 

generous donation, to Sigma Xi. 

The Society will use the donation 

to prepare a grant proposal to get 

the project off the ground. 

“Sigma Xi is the organization that 

can make it happen,” said Fuhs. 

The idea is students would cut out 

a pattern from a cereal box to form a 

cube containing a special geometric 

shape known as an antiprism. Seeing 

the antiprism while researching stealth 

technology, Fuhs thinks this activity 

will capture the attention of students 

because it has concepts that may be 

new to them. 

A picture of a geometry-based activity that 

makes an antiprism cube. (Image courtesy of 

Allen Fuhs.) 

Teachers could bring the activity into 

classrooms with the help of online lesson 

plans. One lesson could be to find 

the third, hidden hexagon once the 

cube is made, and another could be to 

discuss the physics of mirror images. 

“The other aspect is that this antiprism 

cube is a wonderful tool for 

introducing students to the ability 

to think in three dimensions,” 

Fuhs said. 

Additionally, Fuhs donated 50 

copies of his book-on-CD-ROM, 

Tsunami, so the Society could benefit 

from its sales. The book covers 

the causes of tsunamis, how their 

waves propagate, and what happens 

once a tsunami hits shore. 

A Sigma Xi member since 1957, 

Fuhs was a professor for nearly 25 

years at the Naval Postgraduate 

School in Monterey, California. 

He was chairman of the school’s mechanical 

engineering and aeronautics 

departments, and is a distinguished 

professor emeritus. He is also a past 

president and an honorary fellow of 

the American Institute of Aeronautics 

and Astronautics. In 1992, he was inducted 

into the International Space 

Hall of Fame at the New Mexico Museum 

of Space History. He now lives in 

Carmel, California. 

Sigma Xi Plans to Launch the First High School Virtual Chapter 

A high-quality, well-trained, and effective 

workforce of science teachers 

is vital for boosting the national science, 

technology, engineering, and 

mathematics (STEM) pipeline and for 

enhancing student achievement. Partnerships 

between scientists and teachers 

are a unique contribution to the 

professional development of science 

teachers, providing both teachers 

and students opportunities for mentorship 

and engagement in inquirybased 

learning and teaching experiences. 

Such collaborations are equally 

beneficial to scientists, enabling them 

to engage with the public and gain 

a new perspective on their research. 

Sigma Xi has always recognized high 

school researchers by inviting them to 

participate in the annual Student Research 

Conference and the online science 

communication competition, the 

Student Research Showcase, and by 

publishing their research in Chronicle 

of The New Researcher. 

However, high school campuses 

are not recognized as local Sigma Xi 

Sigma Xi member Jeffery Wehr is leading the 

initiative to start Sigma Xi’s first high school 

virtual chapter. 

chapters. With the increasing number 

of research facilities in high schools 

across the country, we would like to 

change that policy. Sigma Xi is planning 

to launch the first high school 

virtual chapter that would connect 

high school researchers and their 

teachers with local Sigma Xi chapters. 

The initiative is spearheaded by Sigma 

Xi member Jeffery Wehr, the principal 

investigator for the Advanced 

STEM Research Laboratory and an 

educator at Odessa High School in 

Odessa, Washington. Participants in 

the virtual chapter will receive Sigma 

Xi benefits and privileges based on 

qualifying as a member or affiliate 

member and will be supported by the 

participating local chapters. 

The initiative is already gaining 

traction at schools in Washington, Florida, 

Montana, Wyoming, and Georgia. 

We hope that this model will inspire 

professionals in higher education institutions 

to assume a greater role in improving 

STEM education and fostering 

the rising generation of scientists and 

engineers. More to come! 

Sigma Xi Today is 

edited by Heather Thorstensen 

and designed by Spring Davis. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


GRANTS-IN-AID OF RESEARCH 

Claude Barnett Honored with Grants-in-Aid of Research Endowment 

Claude Barnett taught physics at Walla Walla 

University in College Place, Washington. 

We see people’s names on street 

signs, buildings, and scholarships—a 

tangible reminder of those 

who came before us. What are the stories 

behind the names? In the case of a 

new Sigma Xi endowment fund named 

for member Claude Barnett, we have 

the answer. 

Barnett was a teacher who encouraged 

his students to follow their curiosity 

and to think creatively. He 

was a physicist who liked to have 

fun, in research and in life. When 

he died last July, friends, colleagues, 

and students expressed deep appreciation 

for how he had influenced 

their lives and enlivened their educational 

experiences. These discussions, 

along with letters of gratitude 

collected over the years, generated 

the idea of honoring and continuing 

Barnett’s work with a donation to create 

a permanent endowment fund. 

The Claude C. Barnett Grants-in-Aid 

of Research Endowment Fund will add 

to the funds that are available for Sigma 

Xi’s Grants-in-Aid of Research program, 

which has been awarding grants 

to students since 1922. The program is 

also funded by the National Academy 

of Sciences and Sigma Xi donors. 

Barnett’s daughter, Jeanie Barnett, 

said supporting Sigma Xi’s grant 

program appealed to her because it 

rewards innovative and multidisciplinary 

research, both of which were 

pillars of what Barnett demonstrated 

as a researcher and teacher. Barnett’s 

wife, Betty, said she appreciated that 

the fund will encourage students to try 

something new and enable them to follow 

their own ideas. 

Barnett stated that a prime goal of 

his teaching was “to inspire students to 

think for themselves and not be mere 

reflectors of other people’s thoughts 

and opinions.” When students asked, 

“What do you want me to do?” he 

would turn it around and ask, “What 

do you want to do for yourself, and 

how may I help you?” 

The endowment will award projects 

that reflect what Barnett practiced: 

independent thought coupled with 

hands-on experimentation. After a 

year of allowing the funds to grow, the 

first grant from the endowment will be 

awarded in 2017 to undergraduate and 

graduate research in physics, biophysics, 

astronomy, computer science, or 

Earth science. Of special interest are 

projects that explore fresh ideas, especially 

those that draw from multiple 

disciplines, including the arts and humanities. 

Barnett believed that weaving together 

ideas and methodology in novel 

ways leads to discoveries. He frequently 

collaborated with colleagues in art, 

music, engineering, languages, history, 

and philosophy. Betty noted that his 

teaching often went beyond the textbook, 

incorporating ideas from his own 

Barnett enjoyed sailing. Here he is at the 

helm on a cruise in the San Juan Islands. (Images 

courtesy of the Barnett family.) 

Walla Walla University named Barnett the 

Distinguished Faculty Lecturer for 1995–1996. 

research and from his life experiences, 

including art, music, and sailing. 

Barnett was a professor of physics 

at Walla Walla University for 43 years 

and chaired the physics department for 

more than two decades. He directed a 

National Science Foundation-funded 

summer conference in 1966 on teaching 

relativity in undergraduate physics 

courses. He was an early advocate of 

using microcomputers in undergraduate 

education, and in the 1980s he developed 

micro PASSIM, a simulation 

and modeling package for the thennascent 

personal computer. 

Barnett was a Sigma Xi member for 

60 years. He was a founding member 

and officer of the Society’s Whitman 

College-Walla Walla University Chapter 

in Washington state and served as 

its president for three years: 1962–1963, 

1966–1967, and 1984–1985. With his 

zest for discovery, the Society’s motto 

“companions in zealous research” resonated 

with him, as did the focus on 

well-formulated, high-quality research. 

“He wanted to do good science and 

reach across boundaries,” said Jeanie. 

“His approach to science was very 

much aligned with Sigma Xi.” 

To donate to the Claude C. Barnett GIAR 

Endowment Fund, go to https://meeting. _________ 

sigmaxi.org/barnett-fund.asp 


2016 May–June 191 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


DIVERSITY 

How to Engage More African Americans in STEM 

What could help more African Americans 

participate in science, technology, engineering, 

and math (STEM)? Sigma Xi 

hosted a Google Hangout to discuss solutions 

to this aspect of the STEM diversity 

gap. The following are main points from 

that conversation, edited for length. 

1. Isolation can be a barrier to keeping 

African Americans in STEM. 

Melanie Harrison Okoro: In particular 

for [Earth system science], there are not 

a lot of women of color, and it could 

have been a point of isolation for me. 

As a graduate student, I thought, “I 

don’t know if this is the career path for 

me,” because it played such a large role 

in my perception of the community, 

the science, and the support behind 

it. Because I was able to go through 

the Minorities Striving and Pursuing 

Higher Degrees of Success in Earth 

System Science program as well as 

other programs—such as the National 

Oceanic and Atmospheric Administration’s 

Graduate Sciences program and 

the National Science Foundation’s Research 

Experiences for Undergraduates 

program—I had the support to continue 

in a field that I absolutely love and 

to own it, not feel isolated in it. 

2. A supportive network can help 

students overcome isolation. 

Danielle Lee: A network is something 

you build before you need it. You need 

to think about cultivating genuine relationships, 

not just with your professors, 

but also consider teaching assistants, 

students who are senior to you, and 

those in different majors or courses. 

What the network does is expand your 

reach to get information about opportunities. 

I recommend undergraduate 

students join at least one club in your 

major as well as one that goes across 

multiple disciplines. Professors can encourage 

students to participate in these 

clubs, to try out a research experience, 

and invite students to seminars. 

Ashanti Johnson: One of my mentors 

told me you have a composite mentor. 

You can never have too many 

parts that make up what you need. 

Sometimes a mentor might not be on 

campus. You need to have people who 

love you and tell you the truth. If they 

care enough to tell you the truth, they 

want you to succeed. 

3. Outreach is needed. 

Johnson: A lot of people of color want 

to see that they’re impacting their 

community. For that, science is a wonderful 

thing to do. One of the things 

that we need to do as a STEM community 

is to be able to make those 

connections clearer. 

Lee: It’s really important that we have 

a multigenerational approach to outreach 

and engagement. We need to let 

the moms and fathers and grandparents 

and community leaders know that 

there is a variety of opportunities out 

there and let them create the environment 

of encouraging students to play 

around and tinker. We need to have 

barbershop, beauty shop, after-church 

conversations about STEM. While 

growing up, no one had actually explained 

to me that a career in science 

that was divorced from medical practice 

was a possibility. Everyone kept 

telling me to be a doctor or a veterinarian 

and I didn’t know that I could do 

what I was doing all along, which was 

studying animals and playing outside. 

4. Organizations that are predominately 

white can play a 

welcoming role. 

Okoro: You have to have that awareness 

that there is an issue. You have 

to be honest about whether or not 

you care. And you have to put a process 

in place to make sure you meet 

your goals. Bring in individuals from 

different backgrounds to talk about 

the issues, be honest about those, not 

threatened by them. Hear what those 

individuals have to say, but then go 

back and do something with that information. 

It’s about the act of doing. 

To watch the full conversation, go to ____ https:// 

__________________________ 

www.sigmaxi.org/programs/critical-issues-inscience/diversity. 

__________ 

Melanie 

Harrison 

Okoro is a 

water quality 

specialist 

with the 

National 

Oceanic 

and Atmospheric 

Administration. She and 

Ashanti Johnson co-wrote the article 

“How to Recruit and Retain 

Underrepresented Minorities,” 

in the March–April 2016 issue of 

American Scientist. 

Meet the Speakers 

Danielle Lee is 

a postdoctoral 

research associate 

at Cornell 

University, a 

TED fellow, 

and blogger 

at The Urban 

Scientist, part 

of the Scientific American Blog 

Network. Her science outreach 

efforts emphasize sharing science, 

particularly to under-served 

groups, via outdoor programming 

and social media. 

Ashanti Johnson 

is the assistant 

vice provost for 

faculty recruitment 

and associate 

professor of 

environmental 

science for the 

University of 

Texas at Arlington. She is president of 

the Institute for Broadening Participation 

and founder and director of 

the Minorities Striving and Pursuing 

Higher Degrees of Success in Earth 

System Science program. 




qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


National Alliance of 

Lollygaggers 

NAL 

The existence of the NAL is doubtful. 

But there’s no doubt that you and other Sigma Xi members could save 

even more with a special discount on GEICO car insurance! 

geico.com/sigmaxi | 1-800-368-2734 

Some discounts, coverages, payment plans and features are not available in all states or all GEICO companies. Discount amount varies in some states. 

One group discount applicable per policy. Coverage is individual. In New York a premium reduction may be available. GEICO is a registered service mark of 

Government Employees Insurance Company, Washington, D.C. 20076; a Berkshire Hathaway Inc. subsidiary. GEICO Gecko image © 1999-2015. © 2015 GEICO 



qM 

qM q 

qM q 

M 

M 

Qmags 




qM 

qM q 

qM q 

M 

M 

Qmags 


BE A PART OF THE LARGEST 

CELEBRATION 

OF STEM 

IN THE 

U.S. 

APRIL 16 & 17, 2016 

WALTER E. WASHINGTON CONVENTION CENTER IN WASHINGTON DC 

EXPLORE THE POSSIBILITIES... 

DON’T MISS THESE EXCITING FESTIVAL EVENTS: 

APRIL 14, 2016 APRIL 15, 2016 

WASHINGTON DC 

WASHINGTON DC 

3000+ 

FUN HANDS-ON ACTIVITIES 

1000+ 

PARTICIPATING ORGANIZATIONS 

150+ 

STAGE SHOWS & SCIENCE CELEBS 

FIND OUT MORE AT: 

______________________________ 

PROUD SPONSOR: 

AMERICIUM 

BOCKIUM 

NOBELIUM 

FOUNDING & PRESENTING HOST: 

K&L GATESIUM 

EINSTEINIUM KRYPTON PLATINUM 

American Physical Society, Francis Goelet 

Charitable Lead Trust, Innovation & Tech Today, 

Engineering.com, Physics Today, NIH, Events DC, 

Booze Allen Hamilton 

IEEE-USA, Illumina, Inc., 

Forbes/Wolfe, 

CrazyEngineers, Association 

for Advancing Automation 

ACT, FEI, National Institute of Standards and Technology - NIST, 

SCOPE-Science and Citizens Organized for Purpose and Exploration, 

Georgetown University, Tufts University, Genentech, Center for 

Biotechnology Education at Johns Hopkins University 



qM 

qM q 

qM q 

M 

M 

Qmags

American Scientist - Cyber Insecurity

Create successful ePaper yourself

Delete template?

Save as template?