Page 62 - All About Space 68 - 2017 UK

Life but not as we know it

ife as we know it is a peculiar thing. It's determined by so many
environmental factors, resulting in the nature and intelligent life Life's
we now know. It began 3.8 billion years ago, when the Earth was only
L 700 million years old, covered with single-celled bacteria. This evolved formula
into the birds flying in the sky, the fish swimming around the vast oceans,
animals of every colour adventuring around the land, but most important of all, it Organic compounds Energy source
led to the evolution of humans. Organic compounds all All living organisms
Even the simplest life on Earth has countless requirements needed to survive contain carbon, which is require energy, such as
our environment, such as water, organic materials (mainly carbon-based) and vital for life on Earth. sunlight, which is vital
It provides us with for photosynthesis.
energy. Without one of these sources, they’re doomed to fail, which is why life
food to eat, among H O
beyond our world is unlikely, because they lack at least one of these aspects. other substances. 2
It’s only until recently that astrobiologists have had the opportunity to examine
alien conditions with such precise detail. Landers and rovers on the surface of
Mars have provided astronomers with unprecedented detail of the Martian surface,
but the results seem to pose more questions then answers. Further out in the Wonders of water
Solar System, we have had revolutionary spacecrafts that have revealed the worlds Water not only fills our lakes
and oceans for us to
in our solar neighbourhood in a whole new light. This has made scientists and drink, but in humans
astronomers worldwide completely rethink what we thought we knew.
it makes up to 60
Spacecraft such as NASA’s Cassini above Saturn, Juno orbiting the king of per cent of our
the Solar System, and New Horizons, which zipped past Pluto back in 2015, have bodies.
shown us that planets may in fact have some subsurface sources of energy, water
and organic materials that have made us rethink the habitability of these planets Organic Energy
as well. Searching beyond our own Solar System, space telescopes such as Kepler
and Hubble are hunting for worlds orbiting other stars (also known as exoplanets).
Kepler alone has discovered roughly 1,200 exoplanets, and the number is rising
all the time. With such a variety of environments, the question that has been
begged for centuries is: what would life on these alien worlds look like?

MARS

Radiation-resistant organisms

Mars is a planet we have studied in With this said, astrobiologists identical to the bacteria on Earth on Deinococcus radiodurans is
extreme detail. This is amplified by have now started studying a the face of it, like tiny cells, but they the most radiation-resistant
the fact that, as of 4 July 2017, there particular category of bacteria called would have adaptations that evolved extremophile known
hasn’t been a day in 20 years that extremophiles. Much like the name to survive that harsh environment.
NASA hasn’t been active on Mars. suggests, these are bacterium that Maybe by eating the iron and
That is 20 years of exploration, thrive in extreme conditions, perhaps minerals in the rocks, like life on
samples and constant analysis, which even extraterrestrial conditions. Earth does as well.”
has shown us that the Martian surface “Extremophiles, as we call them, When asked if there was a
is incredibly harsh and dangerous are the sort of things that survive in particular extremophile that could
for life. The results have shown that similar harsh environments on Earth. survive the barbarous conditions © NASA/JPL-Caltech/Cornell Univ./Arizona State Univ., © Michael Daly, Uniformed Services University
Mars has relatively no atmosphere, Extremophiles that are desiccation of Mars, Dartnell replies, “One of
causing the surface to be constantly resistant, or radiation resistant, are the bacteria I have been working a
bombarded with high-intensity, the sort of organisms that could lot with is called the ‘Deinococcus
ultraviolet radiation from the Sun. survive the Martian surface as well,” radioduran’. It’s the most radiation-
This radiation is the reason the astrobiologist Lewis Dartnell, a resistant organism known on Earth,
surface of Mars has been stripped of Professor of Science Communication so Martian bacteria would have to
its water, leaving it a dry wasteland of at University of Westminster, tells All have certain adaptations to survive
rock and sand. About Space. “Martian life would look the radiation requirement on Mars.”

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