Horizon (1964) Episode Scripts

N/A - Life on Mars

In 2001 a new NASA probe was launched.
Called Odyssey, it was sent to Mars to carry out the most detailed analysis ever of the planet's surface.
What it has discovered may be about to answer one of the great questions and solve one of astronomy's biggest mysteries.
Are we alone in the Universe or is there life on Mars? Ever since people first looked up into the night sky there's been a question that has bothered us all.
From the smallest children to the world's greatest astronomers, all have wondered - are we alone in the Universe? The question of life beyond comes to me strongest at night, looking up at the stars and looking at all those little points of light and wondering is this galaxy full of life or is this it? It's a question that society has often been asking over the ages.
We really just want to know how did we get here, why do we exist, are we the only people in the Universe, are we the only signs of life? This search for life elsewhere in the Universe is perhaps the greatest scientific quest of all.
But so far most efforts have concentrated on just one planet.
Searching for life is a difficult job.
What we'd like to be able to do is travel to all these distant worlds and scoop up samples.
Unfortunately the worlds that we can travel to are the other planets in our solar system and none of them are very good in terms of prospecting for biology.
The best one is probably Mars.
Mars, one of our nearest neighbours, just 60 million kilometres away.
The reason Mars is important is because it's close by.
It's our nearest neighbour to Earth and we'd like to see if life is there because if we can find life in two places in our solar system, we know that life isn't unique here just on Earth, and it's much more likely that life will exist elsewhere, perhaps elsewhere in our solar system, perhaps in other solar systems, other parts of the Universe.
I think it is exciting because it would imply that if life rose independently on Mars, the implication is that life is pervasive throughout the Universe.
This is why Mars has so obsessed scientists.
If life has arisen independently on the planet just next to us, then the chances must be that life could be everywhere.
In which case, we are not alone.
The idea of life on Mars was first popularised by an American astronomer called Percival Lowell, in the 1890s.
He claimed he could see evidence of a civilisation on Mars.
The lines criss-crossing its surface, he believed, were not geological accidents but canals linking Martian cities.
Lowell's vision inspired a global obsession with aliens and spawned thousands of movies about little green men.
But in July 1965 reality intruded.
Mariner 4 became the first probe to fly by Mars and photograph it.
At last the world would see what the land of the little green men really looked like.
When Mariner 4 flew by Mars it just took a few pictures with a very course grain television camera, and what it showed was a surface that could have been the moon.
Clearly there was no civilisations, no canals, probably not even trees and insects.
It was really a bleak landscape that was being photographed there, it really gave the impression that Mars was dead and always been dead since its early history, and that really dashed the hopes of dreamers thinking that maybe there was life there.
Conditions on Mars were so harsh that it was hard to imagine any life surviving there.
The idea of sophisticated aliens was wiped out.
We know that conditions on Mars today are not very good for life.
If you were to go out on Mars without a space suit, and I don't recommend it, but if you were, what would happen is your body fluids would literally start to boil, because the vapour pressure on Mars is lower than the boiling point of water at body temperature.
So this would not be a very good thing in terms of your ears, eyes and nose and throat.
You would quickly suffocate and essentially drown in your own bodily fluid.
It was clear that Mars could not be home to advanced life forms.
For a while it meant that perhaps we were alone after all.
Mars, it seemed, was a dead end.
It wasn't until the years later during expeditions in the 70s that they saw that the image of Mars as a dead planet was not quite right.
After a while when people started thinking about it though, when you looked more into it, then you started realising well yeah, it is desolate, it's very dry, but you know there are other things going on.
Volcanoes and explosions had clearly once torn across this planet, leaving the surface pockmarked and scarred.
Far from being dead, Mars had all the features of once being very much alive.
We started seeing all these incredible things It has mountains there bigger than any mountains on Earth.
It's got canyons that are bigger than the Grand Canyon.
All these volcanoes, parts of Mars was crated, parts weren't.
It's got tremendous altitude variations over the surface of the planet.
It's just a very rich environment.
So that was a very exciting time.
We were surprised by almost everything.
It wasn't just the geology of Mars that was surprising.
It also contained all the basic ingredients for life.
Here was a planet that had all the elements needed for life: carbon, oxygen, nitrogen, sunlight, and yet there was no clear evidence of life.
To me this is mystery story.
It was a sort of - lights on but nobody's home - result.
So life could form on Mars.
There's nothing there preventing it.
We do have the basic building blocks.
These discoveries raised the stakes.
Here was a planet similar to our own.
Mars might not have cities or civilisations but it could be home to other smaller life forms like microbes.
Chris McKay is NASA's leading microbe expert.
He believes that finding even these minute organisms would be of the utmost importance.
If we find life on Mars, we're almost certainly going to find are microbes, little tiny microscopic organisms.
You think well what's the big deal? Well in fact for most of Earth's history, all the life was on Earth was microbes.
And so going to Mars and even finding the smallest, dumbest, littlest bug will still be important because it'll tell us that here in our own back yard life started twice.
And so the hard part is possible.
The evolution into intelligence and humanlike beings is pretty straightforward compared to the question of could it get started.
And there's something about microbes that makes them well suited to surviving on Mars - they're incredibly tough.
They're the organisms also that live in the extremes.
They can live in the very high temperature and very high acid and very high salt.
They define the limits of life and the potential of life.
But hunting for microbes would not be easy.
Mars is 6,700 kilometres wide and it has the same land mass as Earth.
Microbes, on the other hand, are tiny.
You could fit nearly 10 million on just your fingertip.
It would be far harder than finding a needle in a haystack.
Scientists had to narrow down their search.
So they looked for the one thing that had to be present for life to form - a place where you could find microbes.
The search for life is the search for liquid water.
Life on Earth is basically full of water.
Life forms are basically little bags of water with little.
.
a few other ingredients added.
But water is the main component.
Water is what makes it work.
On Earth all life is based on water.
It's the main constituent of every cell.
Because water is basically inert, it's the perfect medium for different types of molecule to flow around, meet and react together.
It enables life to form.
William Boynton is Professor of Planetary Sciences at the University of Arizona, and he's dedicated his life to looking for water on Mars.
The link between life and water is very strong.
Even here in the desert there's life all around us.
Now in looking for life on Mars, we use our basis of knowledge on Earth, and on Earth we know life requires water.
So on Mars we're going to be looking for the places where we can find water.
Just like the desert, Mars may look dry, but there are signs of water there.
It's been known for almost a century that there are ice caps at the Martian poles.
When we look up at Mars we see a dry, dusty planet.
It doesn't look like a place for life.
But there's tiny amounts of water in the atmosphere and we know there are ice concentrations in the poles.
So we're actually very optimistic that because there is at least a speck of water on Mars, there might be a speck of life.
However, while the Poles contain water ice, temperatures there can reach a staggering minus 150 degrees centigrade which meant these were not good places to search for life.
The conditions there are way too extreme.
It's really just too cold and we really need liquid water for life.
What we want to find on Mars is some place where we can find water in the more temperate regions.
What we ultimately need to find is liquid water.
But the first indications were that if life needed liquid water, then Mars was out of luck.
Conditions all over the planet seemed too cold.
There appeared to be no prospect of water anywhere These photographs changed everything.
Taken by the Viking Space Probe in 1976 they showed what looked like dried up river valleys.
You can see one here.
You can see there's a valley through here and you can see it branches, there are tributaries, here's one branch going off here with tributaries.
So this looks very much like a terrestrial river system.
If these were dried up river beds it meant that Mars must once have had the perfect conditions for life.
For Mars to have rivers, it must once have had streams, rain, clouds and an atmosphere, a planet just like the Earth today - if these were rivers.
They had to be sure.
The answers would come in 1998 with the launch of Mars Global Surveyor.
It was equipped with the latest high resolution electronic cameras.
Sections of the valleys were revealed in fantastic detail.
Some valleys had been eroded and filled in with sand.
It was impossible to say how they'd been formed.
They could have been carved by water, or soil, or carbon dioxide.
Then, after they'd searched through thousands of images, they found this - a winding valley 2 km wide.
And at a bend in the canyon, a tiny channel.
The unmistakable trace of an ancient river.
This is the best evidence that we have that climate in the past was different from what it is today.
Only a river would leave a meandering trace like this: only a river would leave the traces of silt they saw in the bend, and only water could carve the winding channel feeding into it.
But they soon found more than just a few rivers.
They discovered evidence that water had once existed on Mars in colossal quantities.
The evidence came from another probe that reached Mars in 1997.
It landed in an enormous channel and sent back images of huge boulders scattered around the Martian surface.
Scientists were puzzled.
What could this strange pattern signify? One man, looking on, knew exactly what those scattered stones meant - Jim Rice.
Rice had seen the same thing in Iceland, one of the few places on Earth with similarities to Mars.
It too is extremely cold, and most of the water is frozen into glaciers.
And also like Mars, buried underground, are massive volcanoes.
This powerful combination has shaped the entire landscape.
When a volcano erupts, lakes of steaming melt water form high up on top of the glacier until the enormous weight of water forces its way down, bursting out from the base of the glacier.
These are the biggest floods on Earth, a surging wall of water stretching for kilometres.
In their wake they leave vast planes littered with boulders.
To a geologist these boulder fields contain unmistakable evidence of the flood waters that ripped through here.
Okay, well this is really a classic textbook example, these two large boulders here.
The size of them indicates this was an enormous flood that deposited these features, but also if you look at their geometry, these boulders are kind of dipping back in this direction.
This has given us information about the path that floodwaters took that deposited these boulders.
The floodwaters were going in this direction when these rocks were deposited.
Now there's other interesting things in the scene here.
For instance, notice some of these smaller rocks are very well rounded, and these little nicked corners of these boulders here, these are kind of percussion marks and these are produced in a water, highly turbulent water column when the boulders and rocks are basically slamming into one another, knocking the corners off.
These things all grouped together just tell you there's no doubt this was a catastrophic flood deposit.
The pictures from Mars showed the rocks in exactly the same pattern as on Iceland.
Here were the slanting boulders lined up by the floodwaters, and the cameras on the rover provided detailed views of the individual rocks with their telltale chipped edges.
It seemed that the vast Martian channels had been carved by enormous floods.
It was final confirmation that Mars had once been warm and wet like the Earth, and that meant that there really was every chance for life to have evolved there.
But even if there had been water, life doesn't start overnight.
Even a simple microbe is the product of complex chemical systems that take millions of years to evolve.
Had the water lasted long enough for life to form? Well, when we look at the history of life on Earth, it appears to start very quickly, maybe a hundred million years.
Now that seems like a long time but for a planet that's short.
So I would guess that if there was water on Mars for a couple of hundred million years, then life had a good shot at getting started there.
And soon they found evidence that water had been there for millions of years.
It was all because of one very important picture.
Sent back in December 2000, it was a vast formations of sedimentary rock.
Sediment is basically made of sand and can only have been deposited over millions of years by a huge body of water like a lake or an ocean.
It showed that there had not only been masses of water, but that it had been around easily long enough for life to form.
The sediments on the surface are now dry and exposed.
If they ever had contained life, it cannot possibly have survived.
However, scientists hope that microbes deeper down might still be alive, frozen in the ground.
To find the actual organic remains of a Martian organism, we're going to need to go to frozen material.
In the ice life might have been preserved frozen in a state of suspended animation.
No one at this stage can know if microbes, formed millions of years ago, could have survived on Mars.
But there are indications that this really is possible.
Antarctica - the closest place on Earth to conditions on Mars.
More extreme even than Iceland - it's the coldest place on our planet.
Until a few years ago, no one thought that anything could survive being deep frozen for millions of years.
But research here has helped change that.
The ground here is permafrost, a mixture of soil and ice frozen together.
A group of Russian scientists have teamed up with NASA to drill down into it in search of micro organisms.
It's work that's been done in Russia for years.
The people found the micro-organisms in the permafrost in the end of 19th century.
It was done especially in Russia when people found mammoths.
Back then it was the mammoths they were after.
But David Gilichinsky's team have now drilled so deep that they've reached permafrost that was laid down millions of years ago.
The frozen cores were taken back to their laboratory.
Samples were taken from the centre of the core, then they looked for signs of life.
They discovered that bacteria can survive in the permafrost for far longer than anyone had thought possible.
In 2001 they found bacteria which may turn out to have been at -20°C for more than 10 million years.
We have some data but we are not sure 100%.
But probably now we have isolated bacteria from Antarctic permafrost it's between 8 and 15 million years old.
Bacteria have been buried alive here in frozen ground since before the beginning of human evolution.
If life can survive in Antarctica for 15 million years, then something could be waiting to be revived on Mars.
These discoveries put new urgency in the quest to find water on Mars.
There was now a real possibility that they might find something alive.
So authorisation came from the very top: send more missions to Mars.
NASA launched several probes with the express purpose of mapping the composition of the Martian surface.
But they never got there.
The first disappeared into deep space.
Another missed its target when its co-ordinates were confused.
One NASA control centre was working in metric, the other in feet and inches.
They never lined up and the probe exploded in the Martian atmosphere.
William Boynton had lost precious equipment on both missions.
But he decided to try one more time.
This was really my third attempt to get to Mars, and some of my colleagues were saying: "Bill, are you crazy? You're doing this a third time? Why are you putting so much time in on this?" And I just couldn't say no.
I think there was just a calling that I had to go back.
So once again he set about designing an instrument to detect underground water on Mars.
After the previous failures the pressure was on.
The role my instrument has taken in this search for water on Mars is we have a device called a gamma ray spectrometer and it's designed to determine what elements are present on Mars that make up the surface, and probably the most important one of those is hydrogen 'cause that's the main constituent element in water.
We have ignition and lift off of a Delta 2 rocket carrying NASA on an Odyssey back to Mars.
On the 7th April, 2001, NASA launched Odyssey carrying Boynton's device, and this time everything went according to plan.
It's really hard to describe exactly what it's like to have an instrument that you've built be perched on top of a rocket and actually get launched off into space, and you think I'm on my way to Mars.
Once in Mars' orbit the instrument was deployed, and the gamma ray detector could get to work.
All elements, when they're struck by cosmic rays from the sun and other stars, release gamma rays.
The wavelength of the gamma rays differs from element to element, so each has its own signature wavelength.
One of these wavelengths corresponds to hydrogen, another wavelength would be iron, another wavelength would be oxygen.
And so you go to that part of the spectrum you're interested in and you see you've got a big peak there.
As Odyssey circled Mars it started to pick up gamma rays.
The strength of the signal indicated how much of any element it had found.
We were hopeful that we would see spots where water had been concentrated.
We weren't sure we would see that.
But it's these kind of things that we're expecting to see and actually very hopeful that we would see.
The data was radioed back from Odyssey to NASA to the University of Tucson and finally to Boynton's desk.
Building up the picture takes a long time because any given spectrum that comes back is only 20 seconds worth of data.
We get a new spectrum every 20 seconds, so we actually slowly build up an image in our database.
As the data came through, a picture started to build.
When I first saw the signal, I was looking through it and at first trying to find the hydrogen signal.
And then when I saw it, it was so big, I couldn't believe it.
I actually had to do some checks to see could this be real or somehow did we mess things up.
It could only mean one thing.
There is water ice on Mars today, and three is masses of it.
Boynton and his team have discovered a vast area of ice in the southern hemisphere.
A froze ocean over 5000km wide.
There's plenty of water there.
What we found is just in the surface.
If we melted that, it would be enough to fill Lake Michigan two times over.
There actually is probably a lot more because we don't know how deep the ice goes, that's just in the upper metre there's that much.
It could be 10 metres deep, it could be 100 metres deep.
There's a lot of ice there.
The ice they have found is trapped in the ground, a permafrost just like in Antarctica.
Crucially it's located at latitudes on Mars where conditions are relatively mild, where there's a real chance of life surviving.
One of the most interesting things about this is its not right up near the South Pole or right not near the North Pole.
It actually goes down to temperate latitudes.
It goes all the way down to about 45° latitude.
This is like the equivalent of Paris France on Earth.
This is really a place where it's much more likely we can find life I feel.
But there was something even better.
Odyssey may not just have found ice.
There may also be liquid water - and that means there could be living creatures there too.
Right now there might be liquid water on Mars.
It's not going to be on the surface but if we go down deep enough, it's almost certain we will find liquid water at some point beneath the ice.
It's all down to the interior of the planet.
Scientists believe that Mars' heart may be a great core of molten rock and metal.
At the very centre it could reach temperatures of almost 2000°C.
This heat is spread outwards, so that despite the very cold surface of Mars, just tens of metres down, it may be warm enough to melt ice.
What Odyssey is seeing really may be just the tip of the iceberg.
There could be, underneath that layer of ice that it could detect, a literal frozen ocean of water beneath that.
Surprisingly there could be life today on Mars beneath the ice in the liquid water.
So the Odyssey results are also telling us that we ought to reconsider the possibility of life on Mars today, search for it more vigorously than we might have.
Odyssey's discoveries mean that there is now a genuine possibility that there is life on Mars.
And if so, then we will soon have to start reconsidering our place in the Universe.
Odyssey's discoveries are so sensational that scientists are beginning to speculate what strange creatures might be there waiting for us.
What might an alien look like? Would they, for instance, be based on the same biological principles as we are? When we look at life on Earth we see that all life on Earth uses the same chemistry and the same genetic code, the same hardware, the same software.
It's really interesting to wonder if life on Mars, if it started independently, would it use the same code, the same chemicals? On Earth everything is based on DNA, but could it be that life on Mars is completely different, that there is an utterly alien way of doing genetics.
Life on Earth is basically proteins and DNA, so we can wonder if there's life on Mars will it also be DNA and proteins, the same type of DNA, the same type of proteins.
One might think that DNA is such a complex arrangement of molecules that it's unlikely to have the same set on another planet.
Equally, we may find that DNA is also on Mars.
It may be that our way is the only way of life.
On the other hand, we might argue that DNA is optimal way to do it and that life is going to discover this best possible solution no matter where it starts.
So we're not sure if life will be different or the same.
My guess is that it'll be different, and if life started separately on Mars, it will have a different genetic structure than life on Earth.
But there will only be one way to find this out conclusively.
To examine life in this detail, someone will have to get up close.
We really have to go find the facts, and the facts are on Mars and we've got to go find them.
We can hypothesise all we want, but until we actually find the facts on the ground, we won't know for sure.
It means that someone will have to go to Mars, and it just so happens that there is an organisation already preparing to go… Bo Maxwell is the UK President of the Mars Society, a group dedicated to colonising our neighbouring planet.
Humans, by their very nature, are explorers.
In our time we've travelled from the African Rift Valley, climbed mountains, crossed oceans and settled just about everywhere there is to settle on Earth.
We've built our houses, our towns, our cities, and now the time has come to move beyond the Earth and Mars offers us the very best opportunity to go to another world and settle somewhere else.
The Mars Society have their very own low cost plan to get to Mars.
Bo is one of the masterminds.
He's working on it from his home in Milton Keynes.
The aim of the Mars Society is definitely to go to Mars.
We want to go there, we want to explore and colonise.
The advantage of sending humans to Mars is our greater ability to explore.
We are much more efficient than robots.
Human beings have a tremendous advantage over robot vehicles.
We have our own intuition, our own intelligence which leaves our robot vehicles standing.
A human being on Mars can stand on the surface, he can look around, she can look around, and instantly spot areas where life may well be possible and life may exist.
The discovery of water ice on Mars has reinvigorated their plans.
Water is the one thing any colonisers would need.
Well hearing that Odyssey had found subsurface water on Mars was enormously exciting for somebody who is involved in planning to send humans to Mars.
Water has a number of important uses for us.
At the most basic, it provides drinking water once it's been purified, and it provides water for hygiene purposes as well.
More important than that, we can electrolyse it.
We can actually split it into hydrogen and oxygen.
Oxygen obviously we can use for breathing and we can also use it as a fuel stock with the hydrogen for our vehicle to come back home, and we can also use the hydrogen itself in fuel cells to power our rover vehicles.
So the ability to use water that exists on Mars is tremendously important to human missions on Mars.
But any colonising of Mars would require extreme action.
Some believe it would need what scientists call 'terraforming', transforming the entire planet into an artificial Earth.
This involves growing plants to create more oxygen, and an atmosphere.
It requires raising the temperature of the planet, raising the atmospheric density through melting the icecaps and freeing up the carbon dioxide.
But the key thing about the water ice on Mars is once we've done that, then we can let that water exist free form on the surface of the planet, and it again will create rivers, lakes, oceans, which we can use and the plants can use to survive.
But plants grown on Mars may be very different from those on Earth.
The lower gravity on Mars, one third of that on Earth, means that both plants and animals might grow taller and thinner.
I think we're all familiar with seeing the giant redwood trees of California.
They're somewhat unusual here on Earth.
They only occur in a few localised places.
On Mars it will be the norm.
You would see these tremendously tall, slim trees, possibly with very high canopies on them as well.
Animal life could be affected the same way as well.
We could see new breeds of animal that we haven't seen before, very tall, thin sheep living on Mars.
But again early days, very much speculative.
This lower gravity would also have implications for any people born there.
If humans live on Mars for many generations, they might develop into different forms than humans on Earth.
They might be taller, they might be thinner, they might have weaker muscles and weaker bones.
It might even be possible that they would not be able to function very effectively on the gravity of Earth.
In that case, Mars' society and Earth's society might split and become effectively two different species.
Of course, any terraforming is still a long way off.
The next few expeditions to Mars will definitely be made by machines.
NASA are sending two rovers capable of travelling over 100 metres a day in search of signs of water, while the Europeans are sending the Beagle 2 probe.
Odyssey will continue to orbit Mars to find out the extent of the ice.
Is it just in the southern hemisphere or all over the planet? Now we're starting to explore what's going on in the north and we're seeing a very similar signal there, but it's very likely we're going to find at least as much ice in the north as we saw in the south, and perhaps even more.
They also want to find out how deep the water goes, and whether there really are underground lakes present as people now suspect.
The mounting evidence for water on Mars means it's looking more and more habitable.
We may he approaching an answer to the great question of whether there's other life out there in the Universe.
My guess is that if you have the right ingredients life is inevitable, but it's just a guess.
We have just one example here on Earth.
We don't know for sure if that's the case, and that's why I want to go to Mars, to test that guess, to turn it from a guess to a scientific fact.
My feeling is that it's likely that there's life elsewhere in the Universe.
There are just so many other stars, so many other planets.
It's hard for me to imagine that this is the only life forms we have is what we have here on Earth.
100 years ago some astronomers believed that there were civilisations on Mars with cities and canals.
They were wrong about the cities, but the water is there, so maybe the life is too, after all.
But ultimately we may have to go there to answer the question - are we alone in the Universe?