The search for life
Life on other planets is always going to be an exciting subject for debate. But how do we find out if life really exists elsewhere in the Universe?
One way is to travel to the planets, either with remotely operated probes or with manned spacecraft.
Mars is currently the only planet in our Solar System on which there is a strong possibility of finding life, either past or present. ESA’s Mars Express is Europe’s first mission to the Red Planet, and its Beagle 2 lander will perform on-the-spot experiments to search for signs of this life.
In 2004, ESA's
Huygens probe to Titan, a moon of Saturn, could provide vital information
towards the great mystery of how life began on Earth. Later, Rosetta will
be the first spacecraft to land on a comet, analysing its surface for organic
compounds that could be the building blocks of life. This will help us to
understand if life on Earth began with the help of 'comet seeding'.
However, these missions are only looking for life within our own Solar System. But how do we find life on planets around other stars? ESA has a plan for searching for this life in other solar systems.
First you have to find the stars that have planets. There are too many stars to analyse them all, so you have to choose a small part of the sky as your starting point. Next you have to decide what kind of planets you are looking for.
telescopes, the only planets we have detected around other stars have been
giant gaseous worlds, like Jupiter, over 10 times the diameter of the Earth.
Scientists believe we should be looking for rocky, Earth-like planets, because
a solid surface is needed on which organic molecules can form and develop
The joint CNES/European mission Corot will be the first spacecraft capable of detecting large rocky planets in short-period orbits around nearby stars.
It will use its
30-centimetre telescope to look at few thousand stars, monitoring changes
in their brightness caused by planets crossing in front of them.
plants give out oxygen and animals expel carbon dioxide and methane. This
flotilla of eight spacecraft will survey 1000 of the closest stars, looking
for rocky planets and analysing their atmospheres for this evidence of possible