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Visit www.mvgroup.org

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In the last few months 
a probe orbiting Mars

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has sent back 
astonishing pictures

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which have rekindled 
the search for life.

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Billions of years ago 
did a river flow through this canyon?

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If these gullies were 
created by water

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and if this was once a lake

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then there is every chance 
we will one day find signs of life on Mars.

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Ever since humans first realised 
there might be life elsewhere in the universe

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we've dreamed 
of aliens on Mars.

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Finding even a primitive life form

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would be one of the most important 
discoveries of all time.

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I think the search for life on Mars

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is a perfect scientific question

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because either answer is 
so philosophically profound and interesting.

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If we found life on Mars

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it would mean there's likely 
to be life throughout the universe

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and if Mars is barren

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then maybe the rest 
of space is too.

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Maybe life on Earth is unique.

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Could life have started on Mars?

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If it didn't 
and the environment was right,

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why not, what, what, 
what was wrong with it?

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Did it take some chance 
in a billion random event to occur,

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or if it did happen

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what happened to it, how come 
there are not Martians running around.

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But there's an even more 
amazing possibility.

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Occasionally Mars is hit 
by such violent impacts

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that the debris is blasted 
right out into space.

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One of these rocks could have been 
the origin of life on Earth billions of years ago.

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Maybe actually life 
started on Mars

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and came to Earth 
via these meteorites.

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Maybe in fact we're all Martians.

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I mean you can ask one of the most fundamental 
questions that scientists can ask:

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are we alone in the universe?

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What's the frequency 
of life in the universe?

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For a planet to support life

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there is one vital ingredient 
it must have,

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one special substance 
which any alien anywhere will need.

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The search for life 
is the search for water.

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Life involves complex 
chemical reactions

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and as far as we know, 
complex chemistry needs water.

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Liquid water is the absolute key, fundamental, 
one and only must have it requirement for life.

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No liquid water, no life. 
It's just as simple as that.

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Mars seems an unlikely place 
to look for life.

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It's far too cold for water.

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Temperatures can be 
minus 100 degrees

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and there's virtually 
no atmosphere

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so every trace of moisture 
is sucked out into space.

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Unprotected a human being 
would last just a few seconds,

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but it seems that Mars 
was once far more hospitable.

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In 1969 NASA launched the first ever probe 
to go into orbit around Mars.

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When Mariner 9 arrived it found the planet 
completely shrouded in a massive dust storm.

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For a month they waited 
for the dust to clear.

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As soon as the images 
started coming back from Mariner 9

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people began to get 
a really different picture of Mars.

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Everyone had expected to see 
a dead ball of rock like the Moon,

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but slowly they started seeing signs 
that Mars had once been very active.

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The first thing that emerged 
was this crater

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that must have been 20 km above the surface 
because it was in the middle of the atmosphere,

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so it was like wow,

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there's something really big there

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that is sticking 
up into the atmosphere

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and above the atmosphere 
and in fact is volcanic

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so all of a sudden 
it wasn't like the Moon at all.

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And then they saw something 
even more amazing

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- what looked like 
dried up river valleys.

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That was a complete surprise.

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I mean this was supposed 
to be a dry, frozen planet

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and here we have evidence of things 
that look like old river beds.

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And it completely changed 
people's view of Mars in that sense

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back to something that might 
have been more Earth-like in the past

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and much more dynamic than the Moon.

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If these were dried up river beds

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it meant that Mars must once have had 
the perfect conditions for life.

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Rivers form from streams,

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streams are fed by rain,

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rain falls from clouds

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and clouds mean an atmosphere.

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Mars must once have been 
like the Earth is today,

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if these were rivers.

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The pictures from Mariner 
just weren't clear enough to be sure.

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Five years later the Viking orbiters 
arrived with better cameras.

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Some of these valleys had faint tributaries 
just like rivers on Earth.

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And these really look 
like terrestrial river valleys

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when you look at them 
and you can see one here.

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You can see there's 
a, a valley through here

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and you can see it branches,

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there are tributaries.

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Here's one branch going off 
here with tributaries,

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so this looks very much 
like a terrestrial river system.

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But many scientists just wouldn't accept 
that rivers had once flowed on Mars.

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The Viking images still weren't 
good enough to settle the argument.

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Then in 1998 
Mars Global Surveyor arrived

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equipped with the latest 
high resolution electronic cameras.

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Sections of the valleys 
were revealed in fantastic detail,

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but these amazing pictures 
were still no use.

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These valleys had all been 
eroded and filled in with sand.

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It was impossible to say 
how they'd been formed.

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Then, after they'd searched 
through thousands of images,

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they struck gold,

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a winding valley 
two kilometres wide

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and at a bend in the canyon 
a tiny channel,

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the unmistakable trace 
of an ancient river.

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This is the best evidence 
that we have

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that climate in the past was different 
from what it is today,

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that there were warmer conditions 
on Mars.

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So Mars must once have been 
warm and wet like the Earth.

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It had rain and flowing rivers.

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Then at some point the atmosphere 
must have thinned and the planet cooled.

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The flowing rivers 
iced over and froze.

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But when did the rivers 
stop flowing?

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Was there time enough 
for life to emerge

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before the last traces 
of liquid water vanished from Mars?

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The river valleys 
are pockmarked with craters,

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so they must have formed 
billions of years ago

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during the beginning 
of the planet's history

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when Mars was still 
being bombarded with meteors,

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but there are other features 
carved into the surface more recently

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which tell a very different story 
about water on Mars

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- giant channels stretching 
for thousands of kilometres.

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Well you see on this image 
a fairly typical example

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and you can see the channel 
on this picture here.

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Here's one side 
of the channel,

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here's the outline, you can see the sort 
of eastern shore of the channel here

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and there's the other side 
of the channel.

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These channels are enormous.

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This crater here is 60 km across,

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so you can see that the, the channel 
down here is, is 200 km across,

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so what happened, there was a lot of 
speculation as to how these channels formed.

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We, we looked into 
the possibility of lava,

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could lava cut a channel like this?

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Liquid hydrocarbons,

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liquid carbon dioxide,

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and of course water.

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Water seemed 
the most likely explanation,

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but how could anyone be sure 
what had carved these monster channels.

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For years scientists have been 
searching for clues on Earth.

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American geologist Jim Rice 
thinks he's found them, in Iceland.

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Buried under vast glaciers are some 
of the most active volcanoes in the world.

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It's a powerful combination 
which had shaped the entire landscape.

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When a volcano erupts

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lakes of steaming melt water 
form high up on top of the glacier

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until the enormous weight 
of water forces its way down

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bursting out from the base 
of the glacier.

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These are the biggest floods 
on earth,

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a surging wall of water 
stretching for kilometres.

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In their wake they leave 
vast plains littered with boulders.

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To a geologist

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these boulder fields contain unmistakable evidence 
of the flood waters that ripped through here.

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OK, well this is really 
a classic textbook example.

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These two large boulders here.

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The size of them indicates 
this was an enormous flood,

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the deposit of these features,

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but also if you look 
at their geometry

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these boulders are kind 
of dipping back in this direction.

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This has given us information about the path 
the flood waters took that deposited these boulders.

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The flood waters were going in this direction 
where these rocks were deposited.

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Now there's other interesting things 
in the scene here.

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For instance you notice some 
of these smaller rocks are very well rounded

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and these little nicked corners 
of these boulders here.

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These are called 
percussion marks

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and these are produced in the water, 
highly turbulent water column

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when the boulders 
and rocks basically slam into one another

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knocking the corners off.

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These things all group together

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just tell you there's no doubt 
this was a catastrophic flood deposit.

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Four years ago the Americans 
sent a probe to land on Mars.

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It was aimed at the middle 
of one of these vast channels.

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For the first time we'd see 
what these strange features looked like

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from close up on the ground.

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The answer was obvious.

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The first view of the landing site 
sent back by the cameras on Pathfinder

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revealed a rock-strewn plain

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just like the boulder fields 
left by catastrophic floods on Earth.

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Here were the slanting boulders 
lined up by the flood waters

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and the cameras on the rover provided 
detailed views of the individual rocks

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with their telltale chipped edges.

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We saw perched rocks that were kind 
of sitting on a very small little,

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as if it had been deposited 
by this flood and actually scoured

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as water had run past it,

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so a whole suite 
of things like that.

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Observational evidence 
very, very strongly argues

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that, that this site is exactly 
what we thought it would be from orbit.

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Pathfinder confirmed that the vast Martian channels 
had been carved by enormous floods,

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so what does this mean 
for the chances of finding life?

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Some of these floods seem 
to be quite recent,

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so did Mars remain warm and wet 
for billions of years?

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Well that depends on 
what caused these giant floods.

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They stop almost instantaneously 
in rubble-filled holes

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with a channel coming out 
and going off to the north

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and so that suggested 
that whatever caused the large channels

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it was, it erupted 
from the ground.

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Mike Carr's theory is that these floods 
are actually a sign that Mars was very cold.

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Deep underground 
geothermal heating melted ice.

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For millions of years 
the water built up

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trapped under pressure 
by a thick layer of permafrost,

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until something broke the crust.

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A vast reservoir of melt water 
is released and surges out of the ground.

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As the water rushes out it would rush out 
so violent that it pulled a rock,

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the aquifer, with it

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so you'd have both rock 
and water coming out

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and then after 
the flood was over

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why the ground would collapse to form 
this rubble-filled hole that we see.

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To Mike Carr these floods are evidence 
that Mars has been deep frozen for billions of years.

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I actually believe that cold climates 
are required to make these large flows.

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You can't get the large flows 
without this thick permafrost zone

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that keeps the water in the ground 
and doesn't allow it to get out.

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So Mars might have been frozen 
for almost its entire history

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with violent floods periodically 
bursting out from beneath the permafrost,

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so what does that mean 
for the chances of finding life?

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Well that depends on 
one other fundamental question.

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The question you have to ask is 
after these enormous floods

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what was the fate of that water?

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The floods on Mars were thousands of times 
bigger than anything on Earth today.

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Where did all the water go?

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The channels flow downhill 
into a giant basin around the north pole.

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Did the floods just 
fizzle out and freeze

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or were they big enough 
to fill this entire basin?

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Did they form 
an ice covered ocean

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which could have sheltered 
life for millions of years?

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NASA's Tim Parker is convinced 
there was an ocean on Mars.

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His evidence comes 
from features carved by a giant lake

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which once filled 
an enormous area of southern Utah.

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We're flying over the, the floor 
of an ancient lake

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called Lake Bonneville that covered 
about half the state of Utah

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when it was at its maximum level 
about 10,000 years ago.

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The best evidence 
that there was a lake here

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is the erosion that occurred 
at the margin of the lake, the shorelines.

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Waves beating on the mountains 
and, and cutting cliffs

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and depositing ridges, 
beach ridges along the margin.

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One of the most dramatic features

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is the flat terrace in the side 
of this volcano cut by the water.

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It's a clear sign this was once 
an island in the middle of a giant lake.

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Tim believes he's seen 
similar features on Mars,

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flat terraces around rocky 
outcrops in the northern basin

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formed by the pounding 
of the ocean waves

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and around the edge 
of the basin

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00:19:41,320 --> 00:19:45,640
Tim believes the old Viking images 
show two faint shorelines

240
00:19:45,720 --> 00:19:49,280
stretching for thousands 
of kilometres.

241
00:19:55,600 --> 00:19:59,040
He suggested these were cut 
by a shrinking ocean

242
00:19:59,120 --> 00:20:02,480
which might have existed 
for a billion years,

243
00:20:04,040 --> 00:20:06,480
but he had no way 
to prove it.

244
00:20:14,160 --> 00:20:21,480
Then last year Global Surveyor beamed back 
the first detailed contour map of Mars.

245
00:20:21,560 --> 00:20:25,920
What we're looking at here 
is a view of the northern hemisphere.

246
00:20:26,000 --> 00:20:29,160
We're looking straight down 
on the pole and this is the pole.

247
00:20:29,680 --> 00:20:32,880
What the colours represent 
are elevations.

248
00:20:32,960 --> 00:20:37,720
This red here is the area of Tharsis 
where there are huge volcanoes

249
00:20:37,800 --> 00:20:42,120
and this one, Olympus Mons, is 
2 and a half times the height of Mount Everest.

250
00:20:42,200 --> 00:20:44,000
It's a huge volcano.

251
00:20:44,280 --> 00:20:48,920
Now the large outflow channels, 
the largest ones are over here.

252
00:20:49,040 --> 00:20:51,400
The water came through here

253
00:20:51,480 --> 00:20:55,840
and down into the low areas 
here which are coloured blue.

254
00:21:00,400 --> 00:21:05,920
Now Jim Head could check 
the height of Tim Parker's proposed shorelines.

255
00:21:06,240 --> 00:21:10,080
A standing body of water 
forms a flat surface,

256
00:21:10,240 --> 00:21:14,320
so shorelines should be level 
along their entire length.

257
00:21:16,080 --> 00:21:21,600
The outer line, called contact 1, 
turned out to be extremely uneven,

258
00:21:21,680 --> 00:21:25,800
but contact 2 seemed 
much more like a shoreline.

259
00:21:25,920 --> 00:21:31,040
The younger contact, contact 2, 
was a much closer approximation to a flat line.

260
00:21:31,120 --> 00:21:33,040
It, it had bumps 
and wiggles as well,

261
00:21:33,120 --> 00:21:35,040
but in many places 
it was really straight

262
00:21:35,120 --> 00:21:39,440
and corresponded to the place 
where Parker had mapped the contact.

263
00:21:40,160 --> 00:21:42,400
But not everyone is persuaded.

264
00:21:43,120 --> 00:21:48,240
Last year the first close-up pictures 
of the edge of the basin came back from Mars

265
00:21:48,360 --> 00:21:51,320
and there's nothing 
that looks like a shoreline.

266
00:21:51,880 --> 00:21:56,840
I do not find the evidence 
of these oceans convincing.

267
00:21:57,080 --> 00:21:59,560
I would expect to be able 
to see something

268
00:21:59,640 --> 00:22:03,560
because the original shorelines 
were depicted on the basis of imaging

269
00:22:03,920 --> 00:22:07,040
and yet when we go back 
and get better imaging

270
00:22:07,120 --> 00:22:10,760
of the, of the places 
where the shorelines have been mapped

271
00:22:10,840 --> 00:22:13,320
we're not seeing 
the shoreline there.

272
00:22:13,400 --> 00:22:19,520
But even on Earth evidence of shorelines 
can disappear when you get too close.

273
00:22:23,960 --> 00:22:27,040
The terrace cut into the volcano 
by Lake Bonneville

274
00:22:27,120 --> 00:22:29,440
just becomes a stretch 
of flat ground

275
00:22:29,520 --> 00:22:32,400
which means nothing 
this close in.

276
00:22:34,040 --> 00:22:35,960
The argument goes on,

277
00:22:36,760 --> 00:22:41,000
but perhaps life didn't need 
a whole ocean to get started.

278
00:22:43,960 --> 00:22:45,360
Just a few weeks ago

279
00:22:45,440 --> 00:22:50,440
NASA released one of the most 
important pictures ever taken of Mars.

280
00:22:57,520 --> 00:23:01,680
Layered rocks in a basin 
hundred of kilometres across,

281
00:23:01,760 --> 00:23:07,320
probably formed by the slow 
build up of sediments in a lake.

282
00:23:10,640 --> 00:23:14,840
Did this lake last long 
enough for life to evolve?

283
00:23:16,880 --> 00:23:21,920
Might these sediments 
contain fossilised Martians?

284
00:23:23,440 --> 00:23:28,480
I think life would get started probably 
in a few hundred or perhaps 1,000 years

285
00:23:28,560 --> 00:23:34,120
so I don't think that we need huge amounts 
of time to, to worry about the origin of life.

286
00:23:34,200 --> 00:23:38,440
We don't, life kicks in 
I think pretty rapidly.

287
00:23:39,600 --> 00:23:43,120
On Earth it was 
about one billion years

288
00:23:43,200 --> 00:23:46,000
after the planet formed 
from a mass of molten rock

289
00:23:46,080 --> 00:23:49,080
that the first microscopic 
fossils appear,

290
00:23:50,000 --> 00:23:51,680
but no one actually knows

291
00:23:51,760 --> 00:23:56,880
how long it took the first living things 
to develop from the primordial soup.

292
00:23:57,600 --> 00:24:01,440
One needs millions to billions 
of years for evolution,

293
00:24:01,520 --> 00:24:05,720
but for the actual onset of life 
I don't think you need much time.

294
00:24:06,040 --> 00:24:07,480
I can look at Mars

295
00:24:07,560 --> 00:24:12,240
and think that this is a typical 
rocky, wet, sunny planet

296
00:24:12,320 --> 00:24:16,240
and life would have inevitably 
started on such a planet.

297
00:24:18,840 --> 00:24:24,880
Many scientists now believe that if life 
did emerge billions of years ago before Mars froze,

298
00:24:24,960 --> 00:24:29,560
craters once filled with water 
are the best place to look

299
00:24:29,920 --> 00:24:32,520
and there's one which stands out.

300
00:24:32,640 --> 00:24:37,440
30 years ago NASA published pictures 
of a strange formation of white rock

301
00:24:37,520 --> 00:24:41,480
in the bottom 
of a crater 90 km across.

302
00:24:43,120 --> 00:24:45,560
I just clocked the fact 
that it had been published

303
00:24:45,640 --> 00:24:47,560
and I thought it was 
a very interesting paper

304
00:24:47,640 --> 00:24:50,680
but I wasn't particularly 
interested in Mars at the time.

305
00:24:51,400 --> 00:24:56,320
It just rather made us 
think in a particular way.

306
00:25:14,800 --> 00:25:17,200
During a trip 
to central Turkey

307
00:25:17,360 --> 00:25:19,720
Mike Russell stumbled 
across a lake

308
00:25:19,800 --> 00:25:23,840
which made him think again 
about the white rocks on Mars.

309
00:25:31,720 --> 00:25:36,320
Near the southern shore 
Mike spotted strange white islands

310
00:25:36,400 --> 00:25:39,280
and decided 
to investigate further.

311
00:25:59,120 --> 00:26:04,440
Well these particular structures 
are probably only a few decades old

312
00:26:04,520 --> 00:26:10,200
and the lake has dropped level 
in the last 30 or 40 years or so.

313
00:26:11,040 --> 00:26:12,680
It's really exciting 
to come back here.

314
00:26:12,760 --> 00:26:16,000
I, I first came out here, I swam out here in 1992

315
00:26:16,160 --> 00:26:21,560
and I couldn't believe my eyes because 
we'd been led to believe these were sand-dunes.

316
00:26:26,880 --> 00:26:33,040
Mike Russell discovered these islands 
were actually something far more extraordinary.

317
00:26:33,400 --> 00:26:38,280
These rocks had been built 
by microscopic organisms.

318
00:26:43,000 --> 00:26:45,440
Photosynthetic bacteria,

319
00:26:45,520 --> 00:26:48,600
the most primitive 
life form on earth,

320
00:26:49,240 --> 00:26:54,960
exactly the kind of creature 
you'd expect to find on Mars.

321
00:26:57,680 --> 00:27:02,600
From then on we started to think well, 
could there have been life on Mars in these craters

322
00:27:02,680 --> 00:27:07,680
and could it be that some of these white 
rocks could have been formed by bacteria.

323
00:27:09,440 --> 00:27:14,920
This lake showed that bacteria 
can build huge rock formations

324
00:27:16,760 --> 00:27:21,880
and as it happened these white rocks 
were made of magnesium carbonate,

325
00:27:21,960 --> 00:27:24,200
exactly what you'd expect on Mars

326
00:27:24,280 --> 00:27:27,640
which has magnesium-rich soil.

327
00:27:31,400 --> 00:27:34,160
So could this mysterious 
white formation

328
00:27:34,240 --> 00:27:39,600
be a sign that life evolved 
in this crater long ago?

329
00:27:41,640 --> 00:27:43,520
There will be vestiges of water

330
00:27:43,640 --> 00:27:48,640
in craters, in lakes and so forth 
on Mars for perhaps 500 million years

331
00:27:48,720 --> 00:27:53,600
and that is absolutely plenty of time 
to evolve photosynthetic bacteria,

332
00:27:53,680 --> 00:27:59,520
so I would expect us to find eventually 
evidence for photosynthetic bacteria on Mars.

333
00:28:01,760 --> 00:28:03,880
And wherever they first appeared

334
00:28:03,960 --> 00:28:07,760
they could have quickly 
colonised the entire planet.

335
00:28:09,000 --> 00:28:11,120
Of course that bacteria 
can get anywhere.

336
00:28:11,200 --> 00:28:12,640
It can last a long time,

337
00:28:12,720 --> 00:28:15,040
they can get blown by winds 
from here and there,

338
00:28:15,120 --> 00:28:20,680
so any standing body of water on Mars 
would have captured some of this,

339
00:28:20,760 --> 00:28:22,920
some of these early bacteria

340
00:28:23,040 --> 00:28:25,760
and they would have then 
colonised any seepages

341
00:28:25,840 --> 00:28:29,200
in any of these crater 
lakes on Mars.

342
00:28:30,680 --> 00:28:37,640
Last year the camera orbiting Mars sent back 
the first close-up pictures of the white rocks.

343
00:28:41,360 --> 00:28:44,040
Could these have been islands in a lake

344
00:28:44,160 --> 00:28:46,640
teeming with bacteria

345
00:28:48,720 --> 00:28:54,480
or are they just sand-dunes sculpted 
and compacted by the Martian winds?

346
00:28:55,640 --> 00:29:02,520
The only way we'll know for sure 
is when we land a probe right on them.

347
00:29:10,760 --> 00:29:14,280
As scientists have pieced 
together the tantalising clues

348
00:29:14,360 --> 00:29:17,720
it seems more and more likely 
that early in its history

349
00:29:17,800 --> 00:29:20,880
there could well have been life on Mars,

350
00:29:25,880 --> 00:29:31,560
but what chance is there that 
anything could still be alive there today?

351
00:29:34,160 --> 00:29:39,120
If it ever started then the chance 
of it surviving up to today

352
00:29:39,200 --> 00:29:46,920
is pretty good because life somehow finds 
niches and adapts to whatever's there.

353
00:29:55,680 --> 00:29:57,400
Until a few years ago

354
00:29:57,520 --> 00:30:03,240
it didn't seem likely that anything could 
survive being deep frozen for billions of years,

355
00:30:03,320 --> 00:30:08,280
but research in one of the coldest places 
on earth has helped changed that.

356
00:30:11,960 --> 00:30:17,880
In northern Siberia the brief summer sun 
breaks up the pack ice and thaws the rivers,

357
00:30:17,960 --> 00:30:23,240
but just below the surface 
the ground stays permanently frozen.

358
00:30:27,640 --> 00:30:32,640
Every year a team of Russian scientists 
comes here to drill into the permafrost

359
00:30:32,720 --> 00:30:35,160
in search of micro organisms.

360
00:30:35,520 --> 00:30:44,080
People found the micro-organisms 
in permafrost in the end of 19th century.

361
00:30:44,280 --> 00:30:52,960
It was done specially in Russia 
when people found mammoths.

362
00:30:54,400 --> 00:30:58,080
Back then it was 
the mammoth they were after,

363
00:30:58,320 --> 00:31:02,480
but David Gilichinsky's team 
have found bacteria and algae

364
00:31:02,560 --> 00:31:07,400
which have been frozen underground 
for an astonishing length of time.

365
00:31:07,920 --> 00:31:11,600
The deeper they go 
the older the permafrost.

366
00:31:17,960 --> 00:31:22,000
The frozen cores are taken 
to their laboratory near Moscow.

367
00:31:22,160 --> 00:31:25,120
A sample is taken 
from the centre of the core.

368
00:31:25,280 --> 00:31:28,880
Then they see 
if anything's still alive.

369
00:31:38,080 --> 00:31:41,800
They've discovered that bacteria 
can survive in the permafrost

370
00:31:41,920 --> 00:31:45,600
for far longer than anyone 
had thought possible.

371
00:31:56,240 --> 00:32:03,880
When they started it was surprise for us 
when they find even 10,000 years old bacteria,

372
00:32:03,960 --> 00:32:10,080
but step by step you can come in Arctic 
two or three million years old.

373
00:32:15,240 --> 00:32:19,600
These micro-organisms have been living off 
the minute amounts of liquid water

374
00:32:19,680 --> 00:32:22,560
which exist even in permafrost,

375
00:32:24,880 --> 00:32:27,960
so could they survive indefinitely?

376
00:32:30,600 --> 00:32:34,400
In Antarctica the ground 
is even colder than Siberia

377
00:32:34,520 --> 00:32:37,200
and it's been frozen 
for much longer.

378
00:32:38,240 --> 00:32:42,680
This is the closest place 
on earth to conditions on Mars.

379
00:32:47,400 --> 00:32:52,080
The Russians have now teamed up 
with NASA scientists to drill here.

380
00:32:52,680 --> 00:32:55,120
A few months ago 
they found bacteria

381
00:32:55,200 --> 00:33:01,160
which may turn out to have been 
at -20 degrees for more than 10 million years.

382
00:33:01,880 --> 00:33:06,880
We have some data, 
but we are not sure 100%

383
00:33:07,040 --> 00:33:13,720
but probably we have now these alleged 
bacteria from Antarctic permafrost.

384
00:33:13,800 --> 00:33:18,480
It's between 8 
and 15 million years old.

385
00:33:20,120 --> 00:33:23,440
Bacteria had been buried 
here in frozen ground

386
00:33:23,520 --> 00:33:26,880
since before the beginning 
of human evolution.

387
00:33:27,720 --> 00:33:31,720
If life can survive 
in Antarctica for 15 million years

388
00:33:31,840 --> 00:33:36,920
then something could be waiting 
to be revived on Mars

389
00:33:37,520 --> 00:33:43,360
and last summer Mars Global Surveyor 
sent back another extraordinary set of pictures

390
00:33:43,440 --> 00:33:49,760
which suggests that in places 
the Martian permafrost has been melting.

391
00:33:56,720 --> 00:34:02,160
The camera has detected hundreds 
of examples of cliff sides on Mars

392
00:34:02,240 --> 00:34:04,960
with little gullies 
running down the cliffs.

393
00:34:05,080 --> 00:34:07,960
Now these look exactly 
like gullies

394
00:34:08,040 --> 00:34:09,120
that would form on the Earth

395
00:34:09,200 --> 00:34:13,360
when, when an underground aquifer 
comes out the side of a cliff,

396
00:34:13,440 --> 00:34:15,360
a little bit of water comes out, 
runs down the gully,

397
00:34:15,440 --> 00:34:18,520
makes a seep, it just 
keeps eroding down there.

398
00:34:18,640 --> 00:34:21,880
These cases on Mars you have 
a gully running down,

399
00:34:21,960 --> 00:34:26,960
then you, in many cases you even have 
a little mud-like deposit at the bottom.

400
00:34:29,240 --> 00:34:31,480
These gullies must 
be very recent.

401
00:34:31,560 --> 00:34:34,800
There's no sign 
of any erosion by the wind,

402
00:34:34,960 --> 00:34:37,600
so if they were carved by water

403
00:34:37,680 --> 00:34:40,960
our whole view of Mars 
would have to change.

404
00:34:41,040 --> 00:34:47,040
It means there could be liquid water 
just below the surface right now.

405
00:34:47,120 --> 00:34:52,240
The temperature here typically is 
-60, -70, -80 degrees centigrade.

406
00:34:52,320 --> 00:34:54,040
It's extremely cold,

407
00:34:54,160 --> 00:34:58,120
so it's hard to imagine how one 
could have seepages of water

408
00:34:58,200 --> 00:35:01,600
under these very cold, 
very cold conditions.

409
00:35:03,400 --> 00:35:08,880
Any water seeping from below would freeze 
long before it reached the surface,

410
00:35:09,120 --> 00:35:11,720
but perhaps the water 
could build up underground,

411
00:35:11,800 --> 00:35:14,560
trapped by a thick 
plug of ice

412
00:35:14,640 --> 00:35:19,560
until the pressure gets so great 
that the water forces a way out,

413
00:35:21,200 --> 00:35:25,600
gushing so fast that even 
in the icy Martian conditions

414
00:35:25,720 --> 00:35:29,800
it could carve a gully 
before freezing again.

415
00:35:38,280 --> 00:35:44,640
Bill Hartmann believes he's found signs 
of what could be melting the water underground.

416
00:35:46,280 --> 00:35:52,440
His team have discovered that volcanoes on Mars 
have erupted more recently than anyone had expected.

417
00:35:52,520 --> 00:35:57,280
The most recent lava flows may be 
less than a million years old.

418
00:35:57,400 --> 00:36:01,600
For every time that you heat up 
the crust of Mars enough to melt rock,

419
00:36:01,680 --> 00:36:04,080
that's 1200 degrees centigrade,

420
00:36:04,320 --> 00:36:06,040
I mean there could be 
a thousand times

421
00:36:06,120 --> 00:36:10,400
when you heat it up to zero 
degrees centigrade and melt ice.

422
00:36:11,200 --> 00:36:13,600
It's not out of the question 
in my mind

423
00:36:13,680 --> 00:36:16,600
that some of these seeps 
have been active 1,000 years ago,

424
00:36:16,680 --> 00:36:20,240
10,000 years ago, 100,000 years ago, 
numbers like that,

425
00:36:20,320 --> 00:36:23,760
or maybe more recently, you know, 
maybe it was six months ago.

426
00:36:25,880 --> 00:36:29,000
If there is still water 
erupting on Mars

427
00:36:29,120 --> 00:36:33,280
the implications for the history 
of life are fantastic.

428
00:36:34,200 --> 00:36:38,480
I'll spin the, the most 
glorious optimistic scenario

429
00:36:38,560 --> 00:36:43,280
which would be that 
the geothermal heating from below

430
00:36:43,400 --> 00:36:47,440
has for 4 billion years, 
the entire history of Mars,

431
00:36:47,520 --> 00:36:52,120
has, has kept open some liquid 
water channels some place on Mars

432
00:36:52,200 --> 00:36:56,880
so there's always been some place 
you could swim from this place to that place.

433
00:37:07,360 --> 00:37:11,480
If there has been water 
on Mars for 4 billion years

434
00:37:11,600 --> 00:37:15,360
what strange creatures 
might be waiting for us?

435
00:37:30,520 --> 00:37:33,080
If this discovery is confirmed,

436
00:37:33,160 --> 00:37:39,400
it will surely be one of the most stunning insights 
into our universe that science has ever uncovered.

437
00:37:39,480 --> 00:37:43,480
The events of that week 
in August 1996

438
00:37:43,560 --> 00:37:45,840
are burned indelibly 
on my brain

439
00:37:45,920 --> 00:37:49,040
and I will never forget 
them until my dying day.

440
00:37:52,520 --> 00:37:53,600
Four years ago

441
00:37:53,680 --> 00:37:58,360
a team of American scientists claimed 
they had found evidence of microscopic life

442
00:37:58,440 --> 00:38:01,240
in a meteorite that had come from Mars.

443
00:38:01,680 --> 00:38:08,760
Allan Hills 84001 has become the most 
intensively studied rock in the world

444
00:38:09,000 --> 00:38:15,400
because proving that this rock contained life 
from Mars has turned out to be very difficult.

445
00:38:15,560 --> 00:38:18,720
What I would like 
to do this afternoon is

446
00:38:18,800 --> 00:38:23,520
lead you through our story 
which is a bit of a detective story.

447
00:38:25,240 --> 00:38:31,200
In 1994 geologists heard about 
a new meteorite which had come from Mars.

448
00:38:31,280 --> 00:38:34,120
We requested three 
or four small fragments,

449
00:38:34,200 --> 00:38:36,800
small chips about the size 
of my fingernail.

450
00:38:38,400 --> 00:38:40,240
Monica Grady's team in London

451
00:38:40,320 --> 00:38:44,480
found unusually large amounts 
of carbonate in the Allan Hills meteorite

452
00:38:44,560 --> 00:38:48,040
which formed orange globules 
in the rock.

453
00:38:50,600 --> 00:38:54,600
Carbonates can sometimes 
be produced by living things,

454
00:38:54,720 --> 00:38:57,800
but the finding didn't 
mean much on its own.

455
00:39:00,840 --> 00:39:05,560
Then David McKay's team 
at NASA took a closer look.

456
00:39:07,800 --> 00:39:09,200
We were looking,

457
00:39:09,320 --> 00:39:12,320
scanning around 
in our electron microscope

458
00:39:12,400 --> 00:39:13,880
looking at Allan Hills

459
00:39:14,000 --> 00:39:17,560
and we particularly looking 
at the carbonates.

460
00:39:19,320 --> 00:39:22,280
There were a lot of rumours 
and, and mutterings in corners

461
00:39:22,360 --> 00:39:25,240
about the possibility 
of something unusual

462
00:39:25,320 --> 00:39:26,920
having been found 
in this meteorite,

463
00:39:27,000 --> 00:39:29,920
but nobody would say 
for definite.

464
00:39:31,480 --> 00:39:37,280
And I started to see some features 
in Allan Hills which were very strange,

465
00:39:37,440 --> 00:39:41,880
somewhat elongated features 
that had segments in them.

466
00:39:42,000 --> 00:39:46,320
The next day we found a few more 
of 'em and we really got excited.

467
00:39:46,760 --> 00:39:50,720
They thought they'd found 
a tiny fossilised Martian.

468
00:39:50,800 --> 00:39:54,600
This is perhaps the most 
controversial part of our presentation,

469
00:39:54,680 --> 00:39:57,040
but we'll show you 
those anyway.

470
00:39:58,200 --> 00:40:02,880
Anybody else who'd seen 
Allan Hills 84001, who'd analysed it,

471
00:40:02,960 --> 00:40:06,440
who'd even had a grandma 
who's seen 84001 was being interviewed

472
00:40:06,520 --> 00:40:10,120
to, to get their, their take 
on, on what had happened.

473
00:40:10,200 --> 00:40:12,440
The scientists will lay 
out for you

474
00:40:12,520 --> 00:40:16,520
how an ancient rock found 
its way from Mars and it got to Earth.

475
00:40:16,600 --> 00:40:19,080
The first time I saw 
the worm-like structure

476
00:40:19,160 --> 00:40:23,120
was at the press conference 
that the NASA scientists had.

477
00:40:23,200 --> 00:40:25,920
Martian micro fossils.

478
00:40:26,000 --> 00:40:30,560
And I must admit I was 
pretty amazed at the structure.

479
00:40:30,640 --> 00:40:33,080
It is 41 billion years old.

480
00:40:33,160 --> 00:40:34,880
It looks like a segmented worm,

481
00:40:34,960 --> 00:40:39,320
it looks like you might think 
a fossilised bacterium would look like,

482
00:40:39,400 --> 00:40:43,560
but then you realise well, 
crumbs, it's very small.

483
00:40:43,640 --> 00:40:46,280
It means we're right 
on the edge

484
00:40:46,360 --> 00:40:50,640
of a potential unbelievable discovery 
that's going to rock our world,

485
00:40:50,720 --> 00:40:53,200
rock our world, 
if it's true.

486
00:40:53,840 --> 00:40:57,480
When McKay's team analysed 
the rock surrounding their worm

487
00:40:57,560 --> 00:41:02,240
they found three different substances 
often produced by bacteria on earth.

488
00:41:02,320 --> 00:41:06,360
These substances could all 
be explained without life,

489
00:41:06,440 --> 00:41:10,880
but McKay had a theory which would 
explain why they were all there together.

490
00:41:11,000 --> 00:41:14,120
Ours was the only one 
that could explain everything

491
00:41:14,200 --> 00:41:17,920
simultaneously with the same 
simple explanation,

492
00:41:18,000 --> 00:41:20,040
that is life on Mars.

493
00:41:20,120 --> 00:41:24,280
They are the remains 
of Martian life.

494
00:41:25,760 --> 00:41:29,880
Is the fact that six things are 
consistent with the presence of life

495
00:41:30,000 --> 00:41:31,840
enough to convince you

496
00:41:31,920 --> 00:41:35,800
that you're making one of the, 
the most sensational claims ever made

497
00:41:35,880 --> 00:41:36,920
and I would say no,

498
00:41:37,000 --> 00:41:42,440
that, that what you need is evidence 
that requires life to explain it.

499
00:41:44,760 --> 00:41:47,560
This may look 
like a Martian worm,

500
00:41:47,840 --> 00:41:54,520
but Ken Nealson has shown how deceptive 
appearances can be at this minute scale.

501
00:41:58,920 --> 00:42:01,280
The pictures 
of the Allan Hills meteorite

502
00:42:01,360 --> 00:42:03,880
were taken using 
an electron microscope

503
00:42:03,960 --> 00:42:05,600
and to get the best images

504
00:42:05,680 --> 00:42:10,920
the rock sample was coated 
with an extremely thin layer of gold.

505
00:42:12,080 --> 00:42:17,240
Nealson's team have been looking at rock 
with a new kind of electron microscope.

506
00:42:17,960 --> 00:42:21,320
This one can work 
without the gold coating.

507
00:42:22,120 --> 00:42:23,720
To my way of thinking

508
00:42:23,800 --> 00:42:26,840
it's very impressive 
how different the samples are

509
00:42:26,920 --> 00:42:29,760
when they're coated 
with gold or not coated.

510
00:42:30,480 --> 00:42:35,920
His uncoated rocks looked jagged 
and crystalline at high magnification,

511
00:42:36,000 --> 00:42:37,840
but add the gold coating

512
00:42:37,920 --> 00:42:40,040
and tiny blobs appear

513
00:42:40,120 --> 00:42:44,400
which are about the same size 
as the famous Martian worm.

514
00:42:44,480 --> 00:42:48,080
The edges now can be 
rounded off with the gold

515
00:42:48,160 --> 00:42:50,960
and even an expert could 
be fooled.

516
00:42:51,040 --> 00:42:55,040
You'll look at it and you'll say 
wow, you know that could be life.

517
00:42:56,800 --> 00:42:59,320
So this might just 
be rock fragments

518
00:42:59,400 --> 00:43:03,560
made to look like a worm 
by a thin coating of gold.

519
00:43:04,000 --> 00:43:06,120
To prove it was once alive

520
00:43:06,200 --> 00:43:09,480
you have to find out 
what it's made of.

521
00:43:13,520 --> 00:43:18,240
In California Ken Nealson's team have been 
developing the kind of techniques

522
00:43:18,320 --> 00:43:24,440
which may one day be needed to probe 
Martian rocks for microscopic life.

523
00:43:31,760 --> 00:43:36,320
Their system works by firing 
a fine beam of electrons at the sample

524
00:43:36,400 --> 00:43:39,000
and it's astonishingly precise.

525
00:43:40,840 --> 00:43:45,280
They can find out what even the tiniest 
microscopic structures are made of,

526
00:43:45,400 --> 00:43:49,040
how much of each chemical 
element the sample contains.

527
00:43:56,280 --> 00:43:59,280
The first tests on the famous 
Allan Hills worm

528
00:43:59,360 --> 00:44:03,840
suggest it has exactly the same 
composition as the surrounding rock.

529
00:44:03,920 --> 00:44:08,000
If that's the case 
this was never living.

530
00:44:20,400 --> 00:44:26,480
The search for life on Mars began 
25 years ago with the Viking missions.

531
00:44:39,040 --> 00:44:40,920
Two landers touched down

532
00:44:41,000 --> 00:44:45,800
and scooped up a sample of the Martian 
soil for chemical analysis.

533
00:44:48,400 --> 00:44:51,400
The billion dollar robots 
worked perfectly,

534
00:44:51,480 --> 00:44:54,960
but they failed 
to find proof of life.

535
00:44:55,360 --> 00:44:57,200
The Americans now realise

536
00:44:57,280 --> 00:45:00,360
that solving one of the greatest 
scientific mysteries

537
00:45:00,440 --> 00:45:03,400
could never be 
that straightforward.

538
00:45:03,560 --> 00:45:05,240
We sent two spacecraft

539
00:45:05,320 --> 00:45:09,320
which had extremely sophisticated 
life detection experiments

540
00:45:09,400 --> 00:45:11,680
and they came back negative.

541
00:45:13,000 --> 00:45:14,440
You don't need to go and land

542
00:45:14,520 --> 00:45:16,480
and poke your arm 
in and pull out soil

543
00:45:16,560 --> 00:45:18,920
and say is there a life 
eating chicken soup there?

544
00:45:19,000 --> 00:45:21,400
It's not, you know, that, 
we already did that

545
00:45:21,480 --> 00:45:24,760
and in a sense 
we didn't learn as much.

546
00:45:24,840 --> 00:45:28,680
We, maybe, maybe, 
and this is arguable certainly,

547
00:45:28,760 --> 00:45:32,480
maybe we asked too specific 
a question too soon.

548
00:45:34,240 --> 00:45:38,800
In 2003 the next missions 
will be heading for Mars.

549
00:45:38,880 --> 00:45:44,600
The Europeans have chosen to send the Beagle 
probe to scratch the surface looking for life,

550
00:45:46,840 --> 00:45:50,840
but NASA will be taking 
a giant leap backwards.

551
00:45:53,520 --> 00:45:56,240
The new rovers they're testing 
at the Mars yard

552
00:45:56,320 --> 00:45:58,480
will not be looking 
for life.

553
00:45:58,600 --> 00:46:03,920
They're just designed to gather basic information 
about the geological history of the planet.

554
00:46:05,320 --> 00:46:08,840
The rovers that we're sending 
have no life detection experiments.

555
00:46:08,920 --> 00:46:10,680
That's not the point.

556
00:46:11,440 --> 00:46:14,240
We've landed three 
places on Mars

557
00:46:14,320 --> 00:46:17,000
and those three places are all 
in the northern lowlands,

558
00:46:17,080 --> 00:46:18,760
they're all kind 
of the same.

559
00:46:18,840 --> 00:46:21,880
Well let's go see what the southern 
highlands are, what are they?

560
00:46:21,960 --> 00:46:25,280
Let's go land in places 
that have these unique signatures,

561
00:46:25,360 --> 00:46:28,200
let's go see 
what Mars is really about.

562
00:46:42,320 --> 00:46:45,200
Rockets on the back shelf: 
fire!

563
00:46:48,720 --> 00:46:53,320
NASA is planning an armada 
of increasingly complex missions.

564
00:47:06,800 --> 00:47:17,040
Three, two, one, release! 
Oh, sweet.

565
00:47:17,680 --> 00:47:20,240
When they've scoured 
every inch of Mars

566
00:47:20,320 --> 00:47:22,840
and they've identified 
the one place on the planet

567
00:47:22,920 --> 00:47:25,200
which is most likely 
to answer the question

568
00:47:25,280 --> 00:47:28,320
then they'll be ready 
to look for life.

569
00:47:28,400 --> 00:47:29,720
Get that kind of information,

570
00:47:29,800 --> 00:47:32,240
get that broad understanding first

571
00:47:32,320 --> 00:47:35,200
before you go in 
to ask the specific question,

572
00:47:35,280 --> 00:47:39,040
so I think that's, that's 
a noble question to try to answer -

573
00:47:39,120 --> 00:47:41,000
is there life on Mars today,

574
00:47:41,080 --> 00:47:45,160
but it's one that you 
dare not ask directly

575
00:47:45,240 --> 00:47:49,920
for maybe 20 years, 
maybe 30 years, maybe even more.

576
00:47:51,520 --> 00:47:53,280
The search for life on Mars

577
00:47:53,400 --> 00:47:58,280
may turn out to be one of the hardest 
problems science has ever faced.

578
00:47:59,600 --> 00:48:05,080
Perhaps it's a question no machine 
will ever be able to answer.

579
00:48:05,880 --> 00:48:09,440
Perhaps Mars will only 
give up its secrets

580
00:48:09,520 --> 00:48:14,120
when the first humans make the journey 
across the Solar System.

581
00:48:14,920 --> 00:48:17,320
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