The deep ocean is an alien world, but incredibly Earth is not the only place in
our solar system that has oceans, oceans that could support life.
Wherever we find water, we find life.
I want to get data back from a probe and be able to say "It's life, Jim, but not
as we know it."
Nasa is planning to launch a mission to explore methane oceans on Titan,
Saturn's largest moon. Yep you heard that right,
Oceans of methane, essentially oceans of liquid farts! They're building a drone to
fly over the surface and look for signs of life.
Can you imagine the freedom of exploring a planet in that way rather than being
stuck on four wheels on the surface?
But most excitingly, they're also planning to build a submarine to dive under
the surface of these methane oceans in search of life.
That first picture.
Are you kidding? That first picture from a submarine, from anybody's submarine
on the surface of an- of a sea on another planet in our solar system changes the
world. I mean, that's- that's something that none of us have ever seen before.
That is true discovery.
That is why we do any of this.
And that would be awesome.
That first picture alone would make this entire mission worth it.
It was back in 2005 that the Cassini–Huygens probe revealed this
surface that really did look quite Earth-like.
In fact, it revealed these lakes that had an uncanny resemblance to the Great
Lakes of North America.
But these aren't lakes of water, they're lakes of methane - and at minus 180 degrees
Celsius, they're far too cold for any life form with an Earth-like
chemistry. So we're looking for life, but not life as we know it.
What I'm really interested in finding is what I call a second genesis of life.
Organisms that are clearly not related to any life on Earth.
But is it even possible to have life that can survive on methane rather than
water? Methane is incredibly flammable.
It's even burned by hobs so that we can cook food.
To find out, researchers at Cornell University took all of the ingredients that we know are
present on Titan and mixed them up.
Not in a test tube though, this isn't Breaking Bad, but in a supercomputer.
Even without water, they were able to make a cell membrane, essentially the outside
wall of a cell, the building block for life.
Now I know the dream is to see some great big tentacle monster like rising up
from the methane oceans.
I mean realistically we're looking at something like microbial life, but that
still will be incredibly cool because it will be completely different to
anything we have on Earth.
They will be entirely and one hundred percent alien.
We tend to think that life would look like us.
You just have to look at the Star Trek movies.
All the aliens kind of look like insects and things that we already know.
But why not be something completely different? Something that we can't imagine,
but something perfectly suited to the- the conditions that are on Titan?
I grew up when Star Trek was just coming out and it was an inspiration to me.
But the key moment was when I realised that the job I wanted was not Kirk's job,
but Spock's job.
He's the one with the tricorder.
He's the one that's detecting life.
And my favourite saying is "it's life, Jim, but not as we know it".
Now, one place we've been looking for life for a long time is the surface of
Mars, because although it's barren and dry today, once upon a time it was
covered in an ocean of water.
Incredibly, traces of that ocean do still exist today.
Four and a half billion years ago, the Martian Ocean covered 19% of the
planet's surface
and was as deep as the Mediterranean.
That was until solar radiation bombarded the planet and stripped of its protective
atmosphere, and the water ended up freezing into ice caps on the poles.
Mars was a water world. It would have been better to characterise it as a water
world, whereas now of course it's a desert world, but it's that water world
that's interesting.
That's the world that may have had life, and that's the world we want to
investigate.
And crucially, it looked how the Earth looked when life first started on Earth.
So if life could have started on Earth, then what's to say that life couldn't
have started on Mars?
Mars isn't the only place that's getting scientists here on the hunt for alien
life excited.
The one I'm really rooting to have life on is Enceladus, which is a tiny moon
of my favourite planet, Saturn.
It shocked us all when we found out that it had water plumes just pouring out of
its South Pole. It wasn't just spewing out of one crack on the surface, but
four huge fissures that were each larger than the Grand Canyon.
That amount of water could only mean one thing:
Enceladus had to have liquid oceans under its surface.
And it's not just Enceladus.
High on the list of places that we'd expect to find alien life is Jupiter's moon
Ganymede, the largest moon in the solar system.
Scientists managed to discover that there was an ocean a hundred kilometres deep,
ten times deeper than any ocean on Earth that was encircling the entire
moon. Each new ocean discovered gives a little bit of a boost to our chances of
finding life elsewhere in the solar system.
But could any living thing survive the extreme environment of space and other
planets lacking protective atmospheres?
Creatures on Earth could give us some idea.
Meet this little fellow.
This is a tardigrade, sometimes known as a water bear or a moss piglet.
Moss piglet! They're just too cute.
These are aquatic
so you'd expect them to die
if they weren't in water, but they actually have a very special ability.
As that sample jar starts to dry out, as that specimen starts to dry out,
what's cool about these guys
is they can survive that extreme desiccation, dry 'em down to like a crispy little
booger.
Now, they might look dead, but as any 90s kid knows, a lot can happen if you
just add water.
It's not really dead, because when we add more water to 'em, when environmental
conditions are good again, they can come right back alive.
This ingenious hibernation mechanism makes them one of the most resilient
creatures on Earth and means they can survive some really extreme and changeable
conditions, just like those in space.
They have even reanimated after years spent frozen in the intense cold of
Antarctica. And they can withstand incredible pressure - and even survived being
shot out of a gun!
It's mind-blowing, dude.
I guess they're like the Han Solo
of the microbial world, like these things could totally survive being frozen in
Carbonite as well.
Took 'em into space, put 'em on a satellite, opened up the door, set 'em outside,
exposed 'em to extreme temperatures, vacuum, right? Hot, cold, huge radiation, and then
when they brought 'em back to Earth, they did what you see in here. Like a
machine, man. You add the water to it, they take them up, cells start to do their
thing again, and they- they come back alive.
It always blows-
Look, I'm an old fat dude, and I've looked at these 100 times, thousands of
times, millions maybe.
(You're not that old)
And well, and in- and when I actually look at 'em under the microscope every single
time, I'm like, dang that's cool, man.
What's clear after finding all of these other oceans elsewhere in the solar
system is that we can't claim to be the only blue planet anymore.
But I'm more excited for the day that we can say that we know that we're not the
only place in the solar system that has life.