Ever since man first looked into the heavens, the most intriguing question has always been,
"Are we alone?".
An icy world, circling Jupiter, could answer
that age old question.
Moons in our Solar system are very important so that we can understand how they formed
and what their interiors are made of, then we'll better understand how our planets formed,
and so we'll better understand where we came from.
We now think that beneath the frozen shell of Europa there lies an ocean with more liquid
water in it than al the seas and lakes and rivers and oceans for the whole of the Earth put together.
And on Earth, where there's water there's life.
Europa first attracted attention back in the 1970s, when the Voyager spacecraft flew past
Jupiter and took the first close up images of its moons.
The Voyager fly bys showed that Europa had a young surface and we already knew it was
icy and we already knew that the ice couldn't
be more than about a 100 kilometres thick.
The question was, is it ice all the way the to the rock or is the ice sitting on top of some
water?
And because it looks like though the surface
has moved around a little bit, a lot of people including Arthur C Clarke, the famous science
fiction author, were suggesting there is water down there below the ice.
The spacecraft is stable. Galileo is on its way to another world.
People have been interested in Europa for many years, but really their interest in it
was focussed following the Galileo spacecraft,
which orbited around the Jupiter system, twenty years ago now.
As we've been exploring Europa we see great signs of activity on the surface, great big
ridges and cracks from the tectonic pulling and stretching
of this world, and also regions where the ocean from beneath has risen up and melted
through the ice.
What the high resolution view from Galileo showed us is this kind of terrain, which is
called ball of string terrain, with multiple generations
of double ridged grooves criss-crossing the surface, but also showed places where the
ball of string terrain has been broken apart in what
we now call chaos. I can show you this here as a global view
with this area magnified here at higher resolution. There's ball of string terrain all over it
except in this chaos region here, where the ball of string
terrain has been broken apart, and at even higher resolution you can see rafts of terrain,
with ball of string texture, separated from one
another by just a jumbled mess. And many of these
rafts can be fitted back together like pieces of a jigsaw, round here or round here, and
what's happened is the ice has become thinner from
below, there's been some melting of the base of
the ice sheet, and eventually the edges of the ice have drifted into the temporarily
exposed ocean which has now refrozen and they are
just locked in place.
When you look at the chaos terrain it's very
much like you see at the edge of the ice pack round Antarctica or in the Arctic Ocean where
rafts of ice have drifted apart and then perhaps refrozen again. So once you've got an ocean,
sitting on rock, below ice, there's all kinds of
ways that that can be inhabited by various types of life.
I think the issue of whether there is life beyond our planet is one of the most current
and portent questions in modern science today.
My research is all about the most hardy, tolerant life forms in our planet the so-called extremophiles,
and one of the most exciting places on Earth for finding extreme living life is Lake
Vostok. Now Lake Vostok is in Antarctica and is
buried beneath miles and miles of solid ice, and the kind of biology we might find in Lake
Vostok would be potentially very similar to what might be able to survive in the sealed
ocean of Europa.
When people talk about life at Europa they think about us. I don't think that's what we'll find.
We'll find bacteria of some kind.
Life on Europa is going to have to have developed without powering itself by sunlight. You
have to live by fuelling yourself and powering yourself from inorganic energy like ecosystems
we find round hydrothermal vents.
But it may be some time before we find out just what lies beneath Europa's ice.
What we really want to do is try and get an understanding about where the life is, how
it might have formed and what we'll do is we'll actually
go into orbit around Europa because people are talking about trying to get below the
surface. And for us to be able to do that, what we
need to have an understanding of, is where the ice layer is at its narrowest.
The next mission to Europa is probably going to always be twenty years into the future
the way things are going. There was meant to be
a joint NASA European Space Agency mission to Europa. That's on hold at the moment. Some
people say it’s on ice waiting for budgets to
be unfrozen so I don't know when it's going to happen. I'm not holding my breath.
This orbiting mission at Europa, that's just a precursor really for us to be able to go
back in the future to be able to tunnel through the
ice and make measurements in the water itself . . .
because for us to be certain that there's life, we really need to be able to go and
almost taste it.
If life began on Europa and began on the Earth, that's twice in one Solar system, then it's
very likely that life began on many places elsewhere
in the galaxy.
Discovering bacteria or life on another body in our Solar system would probably be the
most important discovery that scientists have ever
made. . . Because it will mean that the Earth isn't the only place where the conditions
were just right for life to form. I can't believe that in
our entire Universe we are the only place where the conditions were perfect. There has
to be somewhere else.