Page 64 - All About Space 68 - 2017 UK

Life but not as we know it

TITAN
© Adrian Mann , © NASA/JPL-Caltech/SETI, © NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstadt/Sean Doran
Could life be surfing the
constant storms above Jupiter?
Shape-shifting alien life

Titan is Saturn’s largest moon,
and provides an elusive target for
astronomers. It’s covered in a thick
orange atmosphere, shrouding all the
mysterious behaviour underneath.
On 11 January 2005, things changed
when the Huygens probe detached
from the Cassini spacecraft,
and forged its way through the
atmosphere, divulging the surface
for the first time. Huygens pictured
the landscape of Titan, showing a
rocky, sandy, dull terrain as far as
the camera could see. What wasn’t fundamental biology of our cells.
shown in the image were the lakes Our cells rely upon blobs of water
and oceans of hydrocarbons, such as surrounded by phospholipid bilayers,
methane and ethane. which simultaneously attract and
Before the Huygens detached, repel water to produce these stable,
the Cassini spacecraft imaged the permeable cells.
surface of Titan, and underneath In 2015, scientists at Cornell
the clouds showed huge lakes. The University suggested a new type of
JUPITER only compounds that could exist in cell membrane called an ‘azotosome’,
liquid form at such low temperatures which could theoretically function in
(94 Kelvin/-180 degree Celsius) are a liquid methane. James Stevenson,
Floating life riding methane and ethane. Although a chemical engineer at Cornell
this is a world full of useful organic
University, described this as “the first
the Jovian winds compounds, which Earth is currently concrete blueprint to life not as we
in desperate need of, it doesn’t
know
it”.
This new cell membrane is
provide a suitable environment.
For life to exist on this moon, made up of nitrogen, oxygen and
The king of the Solar System, Jupiter, “ Larger than the you would have to change the carbon, instead of the phospholid
is approximately 140,000 kilometres bilayers we use, but could potentially
(87,000 miles) in diameter, covered greatest whale still remain stable and flexible
in tempestuous winds and an without the presence of water or
atmosphere that never touches a there ever was, oxygen. Although this seems like
surface. The outer layer of Jupiter a microscopic step, it is the first
exists as clouds of gas, down to beings the size important stage to developing
liquid hydrogen in the middle, and life that could survive in such a
towards the centre the pressure and peculiar environment.
temperature are so great that it’s just a of cities” Carl Sagan This image was
pool of metallic hydrogen. life that we know, so it’s possible to taken after Huygens'
On a more positive note, there is think that this life form is something success landing on
Titan's surface
one thing Jupiter has that is required completely abnormal. The late, great
for life... organic compounds. With Carl Sagan, a famous astrobiologist and
an atmosphere full of hydrogen, science communicator, once described
helium, water and ammonia, possible a type of creature that might exist in
life forms would have the chance to his documentary Cosmos: A Personal
metabolise these compounds. Voyage. “The physicist E. E. Salpeter
This does not paint a picture of a and I at Cornell have calculated
place suitable to inhabit any form of something about the other kinds of
life that might exists on such a world,”
said Sagan.
“Vast 'living balloons' could stay
buoyant by pumping heavy gases
from their interior, or by keeping their
insides warm,” Sagan continues. “They
might eat the organic molecules in the
air, or make their own with sunlight, © NASA/JPL/ESA, ©James Stevenson et al.
we call these creatures ‘Floaters’. We
imagine floaters kilometres across,
enormously larger than the greatest
We are learning so much about Jupiter whale there ever was, beings the size
thanks to NASA's Juno spacecraft of cities.”

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