Mountain Lifestyle-Nov 2020-Crestline-Lake Arrowhead edition

The Clavius crater on the moon as seen by NASA’s Lunar Reconnaissance Orbiter.
The SOFIA observatory has detected water ice in shadowed regions of this
sunlit lunar location. Photo courtesy of NASA
The Existence of Water in our Solar
System Changes Everything
by Steven Peter
The discovery of ice on the
two worlds closest to us that we have
investigated thoroughly changes the
paradigm completely about possible
life on our closest neighbors. There’s
an astrobiology saying that where
there is water, there is life. And
where once we believed that we were
the only place to find water, we’ve
instead proven that it’s abundant on
other worlds. While it may not mean
life in the depths of Neptune or on
the frigid, darker poles of Mercury,
it could open the door for new explorations.
The existence of water on the
closest planets could provide way
stations as we move out into the farther
reaches of space. And if there’s
abundant water in our own backyard,
it shows that it may not be so rare to
find and that we may not be alone in
the universe.
Water On the Moon?
A very recent discovery on
our own Moon, and in the darkest
and coldest parts of its polar regions,
a team of scientists have directly observed
definitive evidence of water
ice on the Moon’s surface. These ice
deposits are intermittently distributed
and could possibly be quite ancient.
At the southern pole, most of the ice
is concentrated at lunar craters, while
the northern pole’s ice is more widely
and sparsely spread.
A team of scientists, led by
Shuai Li of the University of Hawaii
and Brown University and including
Richard Elphic from NASA’s Ames
Research Center in California, used
data from NASA’s Moon Mineralogy
Mapper (M3) instrument to identify
three specific signatures that definitively
prove there is water ice at the
surface of the Moon. M3, aboard the
Chandrayaan-1 spacecraft, launched
in 2008 by the Indian Space Research
Organization, was uniquely equipped
to confirm the presence of solid ice
on the Moon. It collected data that
not only picked up the reflective
properties we’d expect from ice but
was able to directly measure the distinctive
way its molecules absorb
infrared light, so it can differentiate
between liquid water or vapor and
solid ice. Most of the newfound water
ice lies in the shadows of craters
near the poles, where the warmest
temperatures never reach above minus
250 degrees Fahrenheit. Because
of the very small tilt of the Moon’s
rotation axis, sunlight never reaches
these regions.
Don’t Forget Mars’ Recent Discovery
There’s also water on Mars.
In a major discovery, ESA’s Mars
Express mission has detected a 12.4-
mile lake beneath the ice on Mars’
surface, fueling the possibility of
finding life. The salty water lake discovery
was released recently in July
2018. The lake is about a mile under
the surface and stretches 12 miles
across. The presence of water under
the Martian polar ice caps has long
been suspected but not seen until
now, the study said.
The discovery raises the
possibility of finding life on the
Red Planet. It’s known that without
water, no form of life as we know
it could exist. Astronomers used radar
data from the orbiting European
spacecraft Mars Express to find the
water. They spent at least two years
checking over the data to make sure
they had detected water and not ice
or another substance. Although evidence
of water was obvious on the
planet’s surface in the form of large
dried-out river valley networks from
ages ago, Mars’ climate does not allow
for water on the surface today.
Due to the depth it was located, it
would be hard to drill down to it, as
it would on Earth. We have been able
to drill down a mile in Antarctica, but
on another planet, it would be a huge
undertaking. It took three and a half
years’ worth of observations—29
separate radar profiles—before they
were confident in their conclusion.
Possibilities on Other Worlds
So to compile what is currently
known and what is presumed
is that still, the best possibility of
life out there is still the moons Enceladus
and Europa. Saturn’s Enceladus
has a higher probability for life
than Jupiter’s Europa. Enceladus orbits
near the rings of Saturn and the
moon spews 1,000 tons of water into
space every hour along with organic
molecules, salt, and other materials.
Recent research suggests the ocean
is also very warm thanks to the tidal
effects from Saturn. Europa was the
biggest contender for life for many
years, with a craggy icy crust hinting
in almost every way at an ocean below.
Thanks to the tidal effects from
Jupiter, the water would be kept liquid
and possibly even warm below
the icy crust, helped by possible hydrothermal
vents.
Jupiter’s moon, Ganymede, is
the largest moon in our solar system,
bigger than even the planet Mercury.
Astronomers had long suspected that
an ocean lies beneath the 100-milethick
ice crust at the surface. Callisto
is similar in composition to Ganymede
and, as the furthest out of the
four Galilean moons of Jupiter, and
is bombarded with the least amount
of radiation. We know there’s water
here—what we don’t know is to what
extent it’s liquid.
Ceres, the largest of Mars’
two moons, was previously known to
be a relatively rocky body. But recent
observations from the Hubble telescope
and evidence from the Dawn
spacecraft, which just arrived there,
have raised an intriguing possibility
that Ceres is less a ball of rock and
more a watery dwarf planet with an
icy mantle and a slushy ocean below.
If it’s true, it would be the nearest
world to Earth with an ocean. Mimas,
Mars’ other moon, is pretty much one
big snowball. There doesn’t seem to
be much more to it than water ice.
Saturn’s moon Dione shows
signs of geologic activity, including
giant mountain peaks and other evidence
pointing to a warmer history.
It’s possible that the moon retains
enough of that heat for a small ocean
to exist.
Pluto is still seen mostly
as an icy world. However, the tidal
forces from its orbit with its largest
moon Charon—combined with what
scientists currently surmise that Pluto
could have hosted an ocean, and
it leaves open the outside possibility
that it’s still around.
Neptune’s largest moon, Triton,
looks a lot like Pluto. The moon’s
surface seems to be a mix of methane
and water ices, much like Pluto, and
there’s the outside chance of an internal
ocean, provided there is enough
heating or radioactive decay
The moons of Uranus (Titania,
Oberon, and Umbriel) show that
Titania and Oberon are likely ice and
rocky materials. Neither has, at the
time, enough evidence to support liquid
water hypotheses without an anti-freeze
agent like ammonia. Three
moons of Saturn (Tethys, Rhea, and
Iapetus), appear similarly frozen,
though there’s an outside chance of
liquid water on Rhea.
Perhaps the most surprising
place water has been detected in the
solar system is Mercury, the closest
planet to the sun. While the surface
is scorching, the poles are often untouched
by the sun’s heat, leading to
an area where ice can accumulate.
In October 2017, the MESSENGER
spacecraft snapped some polar photos
of the frozen ice caps. Liquid water
is unlikely because Mercury is so
hot, but MESSENGER found signs
that some of the accumulations were
recent. Trace amounts of water vapor
have been detected on Venus, Jupiter,
and Saturn.
Right now, Earth is the only
true pale blue dot, the only place
where life as we know it can exist,
where temperature variables create a
wide array of ecosystems and vegetation,
where a thick, luscious atmosphere
enables life by air, by sea, and
by land endowed by our creator.
An artist’s conception of Saturn’s moon Enceladus spewing geysers of water
and hydrogen into the atmosphere. Drawing courtesy of Caltech/NASA.
Page 20 Mountain Lifestyle (C) November 2020