Page 111 - How It Works - Book Of Amazing Answers To Curious Questions, Volume 05-15

Space

What are the icy scars of Tethys?

The craters and mysterious marks
covering the surface of Saturn’s
battered moon

omposed mainly of ice, Tethys orbits
Saturn at a distance of around 295,000
Ckilometres (183,305 miles). It is the fi fth
largest of all of Saturn’s satellites and has
two tiny companions, Telesto and Calypso,
which are both less that 32 kilometres (20
miles) across, held in place by Tethys’
gravity. It is merely one of 62 moons
orbiting the ringed planet, but it has a Images taken
by Cassini in
compelling story. April 2015
Tethys has taken an unprecedented revealed
number of hits during its lifetime, mysterious red
lines slashed
which have given it an almost sponge- across the
like appearance. It has a particularly moon’s surface
noticeable crater known as Odysseus,

which covers nearly five per cent of the
entire moon’s surface – which is
equivalent to a crater bigger than Russia
on Earth.
Enhanced-colour images from NASA’s
Cassini probe have recently highlighted
scar-like red arcs across Tethys’ surface. These © NASA/JPL-Caltech/Space Science Institute
marks must be relatively young because they
seem to have formed over old features such as
craters. Scientists are not sure what causes the Tethys’ crater-covered
surface is evidence of
strange red colour, but one theory is that it’s the
many violent impact
result of chemical impurities in the ice. events in its history

How do water bears fare in space?

Take a look at the first animal to survive in outer space
he tardigrade is sturdy enough creatures withstood the harsh
to handle anything. These combination of extremely low
T small yet robust animals, just pressure, cold temperatures and
half a millimetre (0.02 inches) long, can intense radiation – capable of
be found anywhere from the beyond- damaging DNA – with only slight signs
freezing conditions of the South Pole to of wear and tear when they returned
the high pressures of the ocean fl oor. to Earth ten days later. The tardigrade
What’s more, they can survive more became the first animal to survive

than ten years without food or water, exposure to space. Another group of
in conditions just above absolute zero tardigrade astronauts then headed
to over 150 degrees Celsius (302 degrees into space onboard NASA’s Space
Fahrenheit). Scientists call such hardy Shuttle Endeavour to visit the
creatures extremophiles. International Space Station as part
Being so tough makes the tardigrade of Project BIOKIS, which among other
the perfect astronaut and, in 2007, a things sought to learn more about © Eye Of Science / Science Photo Library
group of these so-called ‘water bears’ how these creatures can naturally
made the journey into space aboard defend themselves from the extreme Tardigrades, also known
as ‘water bears’, are
the European Space Agency’s Foton-M3 stresses caused by the conditions extremely hardy animals
mission. True to form, these resilient in space.

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