Bad Astronomy: Misconceptions and Misuses Revealed, from ...

More documents

Recommendations

Info

HUBBLE TROUBLE 227 A DROP IN THE BUCKET A related misconception is that a telescope’s most important function is to magnify an object, or make it look “closer.” That’s only partly true. It helps to make a small object look bigger, of course, but the real reason we make telescopes bigger is to collect more light. A telescope is like a rain bucket for light. If you are thirsty and want to collect rainwater, it’s best to use a wide bucket. The wider the bucket you use, the more rain you collect. It’s the same for telescopes: the bigger the mirror, the more light you collect from an object. The more light you gather, the fainter an object you can see. The unaided eye can pick out perhaps 10,000 stars without help, but with the use of even a modest telescope you can see millions. With a truly big telescope billions of stars become detectable. The biggest telescopes on Earth have mirrors about 10 meters (33 feet) across, about the width of a small house. There are currently plans to build much larger telescopes. One design calls for a mirror 100 meters (109 yards) across! It’s called the OWL, for Overwhelmingly Large Telescope. It’ll cost a lot, but probably still less than Hubble did. A lot of that cost will probably go into simply finding a place to put it. So Hubble may be small, but remember, it’s above the atmosphere. The air glows, which washes out faint objects when viewed from the ground (see chapter 11, “Well, Well: The Difficulty of Daylight Star Sighting”). Hubble has darker skies and can see much fainter objects. The atmosphere also moves, so stars seen from the ground wiggle and dance (see chapter 9, “Twinkle, Twinkle, Little Star”). This spreads out the light from stars, making faint ones even more difficult to detect, especially if they are near brighter stars, which overwhelm them. With Hubble above the atmosphere, it avoids this effect and can more easily spot fainter stars. Between the much darker sky and ability to see faint objects, it holds the record for detecting the faintest objects ever seen: in a patch of sky called the Southern Deep Field, one of Hubble’s cameras spotted objects ten billion times fainter than you can see with your unaided eye. That’s a pretty good reason to loft a telescope a few hundred kilometers off the ground.
228 BEAM ME UP THE CASE FOR SPACE Still, it’s not easy getting something that size into space. For a long time, Hubble was the largest single package delivered to orbit from the Space Shuttle. The Shuttle can only get a few hundred kilometers above the Earth’s surface, and schlepping the 12-ton Hubble up made it even harder to get there. Using the Shuttle’s robot arm, in April 1990 astronaut Steve Hawley gently released Hubble into the Earth’s orbit, where it still resides, about 600 kilometers (375 miles) above the Earth’s surface. It’s another common misconception that Hubble is like the starship Enterprise, boldly going across the universe to snap photos of objects no one has snapped before. In reality, the distance from Hubble to the surface of the Earth is about the same as that between Washington, D.C., and New York City. Hubble is only marginally closer to the objects it observes than you are! Sometimes it’s actually farther from them; it may be observing an object when it’s on the far side of its orbit, adding a few hundred kilometers to the distance the light travels from the object to Hubble’s mirror. FILM AT 11:00 Which brings us to yet another common misthought about Hubble. Despite what many newspapers and television programs may say, Hubble has never taken a single photograph of an object. Hubble isn’t a giant camera loaded with ISO 1,000,000 film. Hubble uses electronic detectors to take images of objects. These detectors are called charge-coupled devices, or CCDs. You’ve probably seen or used one of these yourself: handheld video cameras have been using CCDs for years, and digital cameras use them as well. They are much better than film for astronomy because they are far more sensitive to light, making it easier to detect faint objects. They are stable, which means that an image taken with one can be compared to another image taken years later. That comes in handy when astronomers want to look for changes in an object’s shape or position over time. CCDs store data electronically, which means the data can be converted to radio signals and beamed back to Earth for processing. That’s their single biggest advantage over film
Page 2:
Bad Astronomy PPPPPPPPPPPPPPPPPPPPP
Page 6 and 7:
Bad Astronomy PPPPPPPPPPPPPPPPPPPPP
Page 8 and 9:
CONTENTS Introduction 1 PART I Bad
Page 10:
CONTENTS vii Recommended Reading 25
Page 13 and 14:
2 BAD ASTRONOMY luminous, against a
Page 15 and 16:
4 BAD ASTRONOMY who fully well knew
Page 17 and 18:
6 BAD ASTRONOMY But if they cannot
Page 20 and 21:
PART I PPPPPP Bad Astronomy Begins
Page 22 and 23:
1 PPPPPP The Yolk’s on You: Egg B
Page 24 and 25:
THE YOLK’S ON YOU 13 and they mak
Page 26 and 27:
THE YOLK’S ON YOU 15 ished announ
Page 28 and 29:
THE YOLK’S ON YOU 17 Of course it
Page 30 and 31:
THE YOLK’S ON YOU 19 with the wea
Page 32 and 33:
2 PPPPPP Flushed with Embarrassment
Page 34 and 35:
FLUSHED WITH EMBARRASSMENT 23 much
Page 36 and 37:
FLUSHED WITH EMBARRASSMENT 25 Equat
Page 38 and 39:
FLUSHED WITH EMBARRASSMENT 27 still
Page 40 and 41:
IDIOM’S DELIGHT 29 press my heigh
Page 42 and 43:
IDIOM’S DELIGHT 31 friend about w
Page 44 and 45:
IDIOM’S DELIGHT 33 Incidentally,
Page 46:
IDIOM’S DELIGHT 35 So you might c
Page 49 and 50:
38 FROM THE EARTH TO THE MOON and t
Page 51 and 52:
40 FROM THE EARTH TO THE MOON body
Page 53 and 54:
42 FROM THE EARTH TO THE MOON red l
Page 55 and 56:
44 FROM THE EARTH TO THE MOON top o
Page 57 and 58:
46 FROM THE EARTH TO THE MOON photo
Page 59 and 60:
5 PPPPPP A Dash of Seasons: Why Sum
Page 61 and 62:
50 FROM THE EARTH TO THE MOON Clear
Page 63 and 64:
52 FROM THE EARTH TO THE MOON Equat
Page 65 and 66:
54 FROM THE EARTH TO THE MOON Howev
Page 67 and 68:
56 FROM THE EARTH TO THE MOON the S
Page 69 and 70:
58 FROM THE EARTH TO THE MOON These
Page 71 and 72:
60 FROM THE EARTH TO THE MOON the d
Page 73 and 74:
62 FROM THE EARTH TO THE MOON That
Page 75 and 76:
7 PPPPPP The Gravity of the Situati
Page 77 and 78:
66 FROM THE EARTH TO THE MOON is co
Page 79 and 80:
68 FROM THE EARTH TO THE MOON a poi
Page 81 and 82:
70 FROM THE EARTH TO THE MOON you
Page 83 and 84:
72 FROM THE EARTH TO THE MOON Moon,
Page 85 and 86:
74 FROM THE EARTH TO THE MOON that
Page 87 and 88:
76 FROM THE EARTH TO THE MOON galax
Page 89 and 90:
78 FROM THE EARTH TO THE MOON that
Page 91 and 92:
80 FROM THE EARTH TO THE MOON exact
Page 93 and 94:
82 FROM THE EARTH TO THE MOON The P
Page 95 and 96:
84 FROM THE EARTH TO THE MOON But n
Page 97 and 98:
86 FROM THE EARTH TO THE MOON of th
Page 99 and 100:
88 SKIES AT NIGHT ARE BIG AND BRIGH
Page 101 and 102:
Page 103 and 104:
Page 105 and 106:
Page 107 and 108:
Page 109 and 110:
Page 111 and 112:
100 SKIES AT NIGHT ARE BIG AND BRIG
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
13 PPPPPP Shadows in the Sky: Eclip
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
16 PPPPPP When the Universe Throws
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Page 161 and 162:
Page 164 and 165:
PART IV PPPPPPP Artificial Intellig
Page 166 and 167:
17 PPPPPP Appalled at Apollo: Uncov
Page 168 and 169:
APPALLED AT APOLLO 157 My question
Page 170 and 171:
APPALLED AT APOLLO 159 Admittedly,
Page 172 and 173:
APPALLED AT APOLLO 161 These belts
Page 174 and 175:
APPALLED AT APOLLO 163 solid-state
Page 176 and 177:
APPALLED AT APOLLO 165 However, you
Page 178 and 179:
APPALLED AT APOLLO 167 flow well be
Page 180 and 181:
APPALLED AT APOLLO 169 One of the m
Page 182 and 183:
APPALLED AT APOLLO 171 The shadows
Page 184 and 185:
APPALLED AT APOLLO 173 they put tog
Page 186 and 187:
WORLDS IN DERISION 175 Many people
Page 188 and 189: WORLDS IN DERISION 177 Today, we wo
Page 190 and 191: WORLDS IN DERISION 179 do now for t
Page 192 and 193: WORLDS IN DERISION 181 This premise
Page 194 and 195: WORLDS IN DERISION 183 Venus’ orb
Page 196 and 197: WORLDS IN DERISION 185 or mainstrea
Page 198 and 199: 19 PPPPPP In the Beginning: Creatio
Page 200 and 201: IN THE BEGINNING 189 want to believ
Page 202 and 203: IN THE BEGINNING 191 squarely at th
Page 204 and 205: IN THE BEGINNING 193 tem started ou
Page 206 and 207: IN THE BEGINNING 195 it’s natural
Page 208 and 209: ( a.) ( b.) ( c.) IN THE BEGINNING
Page 210 and 211: IN THE BEGINNING 199 their lives, e
Page 212 and 213: IN THE BEGINNING 201 ence isn’t l
Page 214 and 215: MISIDENTIFIED FLYING OBJECTS 203 la
Page 216 and 217: MISIDENTIFIED FLYING OBJECTS 205 In
Page 218 and 219: MISIDENTIFIED FLYING OBJECTS 207 an
Page 220 and 221: MISIDENTIFIED FLYING OBJECTS 209 Ne
Page 222 and 223: MISIDENTIFIED FLYING OBJECTS 211 ni
Page 224 and 225: MARS IS IN THE SEVENTH HOUSE 213 Th
Page 226 and 227: MARS IS IN THE SEVENTH HOUSE 215 as
Page 228 and 229: MARS IS IN THE SEVENTH HOUSE 217 Mi
Page 230 and 231: MARS IS IN THE SEVENTH HOUSE 219 of
Page 232 and 233: PART V PPPPPP Beam Me Up We’ve tr
Page 234 and 235: 22 PPPPPP Hubble Trouble: Hubble Sp
Page 236 and 237: HUBBLE TROUBLE 225 The Hubble Space
Page 240 and 241: HUBBLE TROUBLE 229 for space telesc
Page 242 and 243: HUBBLE TROUBLE 231 staking your sci
Page 244 and 245: HUBBLE TROUBLE 233 also used to say
Page 246 and 247: HUBBLE TROUBLE 235 can assure you t
Page 248 and 249: STAR HUSTLERS 237 That’s a tall o
Page 250 and 251: STAR HUSTLERS 239 the names aren’
Page 252 and 253: STAR HUSTLERS 241 I’ll note that
Page 254 and 255: STAR HUSTLERS 243 The star “Phili
Page 256 and 257: 24 PPPPPP Bad Astronomy Goes Hollyw
Page 258 and 259: BAD ASTRONOMY GOES HOLLYWOOD 247 ar
Page 260 and 261: BAD ASTRONOMY GOES HOLLYWOOD 249 si
Page 262 and 263: BAD ASTRONOMY GOES HOLLYWOOD 251 it
Page 264 and 265: BAD ASTRONOMY GOES HOLLYWOOD 253 Tr
Page 266 and 267: BAD ASTRONOMY GOES HOLLYWOOD 255 In
Page 268: BAD ASTRONOMY GOES HOLLYWOOD 257 Si
Page 271 and 272: 260 RECOMMENDED READING with the ma
Page 273 and 274: 262 RECOMMENDED READING One of the
Page 275 and 276: 264 ACKNOWLEDGMENTS Vergano, for gi
Page 277 and 278: 266 INDEX “Astrology: Science or
Page 279 and 280: 268 INDEX earthquakes, 130, 182 pla
Page 281 and 282: 270 INDEX Islam, 58-59 “It’s Sp
Page 283 and 284: 272 INDEX neutrons, 34 in stars, 98
Page 285 and 286: 274 INDEX Sirius, 100, 107 size con
Page 287 and 288: 276 INDEX triangles, 148 true scien
show all

Bad Astronomy: Misconceptions and Misuses Revealed, from ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?