Exploring Mars The Sky at Night

Good evening. We are going to go on a journey to Mars.

Now Mars is a world, in some ways, fairly similar to the Earth.

And it was always been of special interest, mainly I think

because of the chance of finding life there.

So is there any life on Mars? We're still not sure.

We are trying to find out.

But meanwhile, just for a moment, cast your mind back to the 1950s.

Science fiction enthusiasts had great fun with Mars then.

Do you remember Quatermass?

You know, when I was a boy, it was the great burning topic.

Were there really canals there, and who made them?

I remember my disappointment

when somebody proved that Martians couldn't exist.

It's a funny word. Worn out before anything turned up to claim it.

Martian.

Welcome now, Dr Chris Lintott.

Chris, I enjoyed Quatermass immensely.

You didn't see it in the original but you've seen it since. What do you think?

It's fantastic, isn't it? This vision of Mars as the place

from which aliens come, which goes right through 20th-century sci-fi.

Even though we knew there weren't aliens on Mars,

we'd come a long way from the 19th-century view.

Back then observers with some quite large telescopes were drawing

elaborate canal structures on the planet,

believing these were the products

of technologically advanced civilisations.

Pure tricks of the eye.

But of course, there are dark patches on Mars,

once thought to be seas and then thought to be tracts

of low-type vegetation. So what you've got to remember,

on Mars the air is very thin indeed, what we'd normally call a vacuum,

and it's also dry and there's no water.

There's ice but no water.

So the question going into the space age was whether vegetation could survive on Mars.

And I know The Sky At Night demonstrated pretty quickly

-what would happen if you tried to plant things there.

-We did.

We took two cacti, one we kept under earth conditions

and the other we subjected to what we thought were Martian conditions,

and this is what happened.

Well, it's rather unlikely, I think,

that any of our higher terrestrial plants would survive under Martian conditions

although it's just possible that some very lowly forms

which we've not yet tested may.

But just to show you the fate of higher plants,

I brought along tonight two cacti.

This cactus has been quite healthily growing under earth conditions,

and you see it's quite a nice, firm looking sort of cactus.

This one here has spent one night under Martian conditions

and I think you can see without any doubt

that it's got a distinctly "morning after" appearance.

Well, despite the lack of aliens,

it had become very clear that Mars is a fascinating world.

But of course, it never comes much closer than 35 million miles,

so we are bound to be limited. The best way was to use space probes.

The first probes went up in the early 1960s,

both Russian and American.

But the first real success came with America's Mariner 4 in 1965.

Yes, and like all the early probes,

this just give us a fleeting glimpse of Mars as it shot past.

It's much easier to do a flyby of the planet than it is to slow down

and go into orbit, so the early probes just shot past

and sent back what they could.

Mariner 4 saw some amazing things nonetheless.

For example, it showed us the first real images of craters

on the surface of Mars, something you couldn't see from Earth.

And then came those marvellous pictures from Mariner 6.

We've just had some amazing photographs sent back

by the American probe to Mars, Mariner 6.

Mariner 7, by the way, has been brought back under control

and we await news from that, but meanwhile

we have this superb series of close-ups from Mariner 6

and I'd like to show you those pictures now,

beginning with Mars as seen by Mariner from a distance

of more than 700,000 miles, which of course is a great deal

further than the moon is from the earth.

Even so, you can see some of the dark areas which may be vegetation

and at the bottom you can see the white polar cap,

always thought to be due to some kind of icy or frosty deposit.

And just look at that.

Craters on Mars very similar to those on the moon.

And the largest crater on that picture is about 160 miles across.

Remember, when Mariner took that picture,

it was only about as far from the surface of Mars as we are from Moscow.

I wonder how those craters got there. What are they?

Are they due to things hitting Mars or are they volcanic?

I believe myself that most of them are likely to be volcanic

but I remain to be proved wrong.

Let me show you know the most spectacular of all these pictures sent back so far by Mariner 6.

Just look at that, it's a crater 24 miles in diameter

seen from 2000 miles. And just to give you an idea of scale,

the area covered in that picture is about 63 miles by 48 miles,

and I think you'll agree that that crater on Mars is very similar to a crater on the moon.

They may not look much compared to what we have now but those images are stunning.

It must have been wonderful to see such detail on a planet

that's so frustrating through the telescope.

It teases you with detail, but you never see anything like this

and then suddenly you have Mars laid out for you.

Yes, but don't forget, by sheer bad luck,

the first Mariners went over Mars

in what we now know are the least interesting parts.

For a time, it was thought Mars might be

rather a flat, a dull kind of world. Well, it's not.

-Mariner 9 showed that.

-But it had problems on the way in.

Mariner 9 was supposed to go into orbit around Mars.

It did but it found a dust storm waiting for it.

Now, although the Martian atmosphere is so thin,

it evidently can produce dust.

And we've seen dust storms before.

In fact, I for one, was prepared for this

because for some weeks now I've been watching it from my observatory

way down in Selsey in Sussex.

And I've got three drawings here which will show, more or less, what I mean.

In September, before the dust storm started,

with my telescope I could see a great deal on Mars

and here's one of the drawings I made then.

This shows the southern polar cap at the top,

it shows that rather V-shaped marking

which we know as the Syrtis Major.

One of those markings we always thought to be due to vegetation

although they're not so sure now.

Above Syrtis Major, you can see a rather featureless area

which we call Hellas. And then, in October, the dust storm started.

And there's a drawing that I made on October 4th

and this time, as you can see, the polar cap is very difficult to see

and the other features are very much less clear.

And then the dust storm developed and this last drawing was made

this month on November 1st, and there again in the middle, you can see the V-shaped Syrtis Major,

but now you can only see a trace of it,

and the entire southern part of the planet appears to be hidden

by these swirling clouds of dust. And that is why, so far,

we haven't had the spectacular pictures from Mariner 9

that we'd hoped we would. Although undoubtedly they will come as soon as the dust clears.

Global dust storms like that encountered by Mariner are relatively common on Mars,

but they certainly puzzled The Sky At Night back in 1971.

When you're talking about a planet like Mars where the atmosphere

is so extremely thin, approximating what we'd normally call a vacuum,

just how can it hold particles in suspension

and how could those particles be whipped up?

Arthur, I know you've got some ideas.

I've got a little demonstration here, Patrick. This is a magnetic stirrer.

In this little beaker on the top, I'll put some very fine silica dust.

And if I then switch on the stirrer,

which rotates the little bar magnet,

I think you can see there

that there is a considerable cloud of dust rising.

-There certainly is.

-Of course, this means that we've got here

the thick atmosphere of the Earth.

This doesn't apply on Mars, and what puzzles me

is how on earth the Martian atmosphere

manages to sustain a dust cloud. And so for this demonstration,

I've brought along a chunk of Martian atmosphere,

which is inside this desiccator, which has been evacuated to, er,

-it's one hundredth, Gilbert, is it?

-Less than one hundredth.

Of atmospheric pressure.

If I can get this magnetic stirrer to rotate again in here.

-There it goes.

-There it goes.

We can see that there isn't any dust coming up at all from this,

you see, because the atmosphere's not thick enough to sustain it.

And now to try and show that we're not really cheating,

I'll open this little cock on the top and let air in.

-I have to do this very gently.

-There we go.

-Yes, you see what happens?

Well, that seems to be an experiment

to prove there can't be dust clouds on Mars.

I don't understand it, Patrick.

It may simply mean that the dust particles on Mars are very much finer

than anything we have.

Well, it was a good experiment

but we now know we got the atmosphere of Mars all wrong.

Yes, the composition's different from what you would have guessed then.

The dust is different, too. It's much smaller and finer grained

than you would otherwise have expected and that makes it easier

to get up into the atmosphere.

These days, we're used to dust storms but we also see things

like dust devils whipping across the Martian surface.

And the winds are quite strong there, although not very much force,

because the air is so thin. Barometric pressure below 10 millibars everywhere.

That's right, but still this quite evolved, dynamic weather system.

In fact, weather on Mars has become a whole research topic on its own.

But never mind the atmosphere.

What Mariner 9 really showed us were the glories of the planet.

For example, Olympus Mons.

Olympus Mons, a volcano taller than our Mount Everest,

much taller, and formerly seen as Nix Olympica, the Olympic snow.

We didn't know what it was!

But how can you not have realised it was a mountain? This thing's taller than Everest.

-How could you not see it from Earth?

-We couldn't see it clearly enough.

It merely appeared as a patch. It might have been a lake or snow.

We simply didn't know. It took Mariner 9 to tell us.

And here it is. Very interesting indeed.

You can see there the crater-like structure

and you can see that it's got rather scalloped edges.

And it is rather obviously a volcanic caldera.

Here's another view of Nix Olympica.

And you can see there a very considerable amount of detail.

And it looks very much like a volcano of the Hawaiian type,

only the base is about 300 miles wide, which means that it's even bigger than Hawaii.

So Mars does seem to have been a world where vulcanism

has played a very, very important part.

Well, as much as you'd like to have visited Olympus Mons,

it's a little difficult, even for The Sky At Night.

But you did do the next best thing,

visiting Mount Teide in the Canary Islands back in 1973.

And I have to say, it looks pretty Martian to me.

Now how do you think Teide matches up with a Martian caldera?

I think very exactly. One looks, for example,

at the beautiful pictures taken by Mariner 9,

looking straight down on the top of Nix Olympica, for example.

Here is a case of a caldera just like this one,

active in the only recent past, I would imagine.

Would you say, Ron, looking as we are now round the caldera of Teide,

we are looking at a small version

of the scenes that may be found when explorers finally go to Mars?

I'm fairly sure, without the vegetation,

without the blue sky, this is a typical solar system view.

'Filming outside did pose a few problems for you, Patrick.'

Sorry.

I had hat problems.

-The hazards of filming, I think, Patrick.

-You could say that!

Blast and hell!

Well, Mariner 9 was a great step forward.

What you really want to do is to land and see what Mars is very like.

And that brings us on to the Viking programme.

Yes, landing on Mars is a bit of a nightmare.

It's something that's challenged space agencies throughout the history of exploration.

The Russians had some tries. They had one success, Mars 3.

-Not really a success.

-Well, it lasted for 15 seconds on the surface,

-so we'll give them some credit.

-Yes.

-But it's the challenge of getting through Mars's thick atmosphere.

It's not thick enough, like the Earth's,

to allow you to break on parachutes the way the Apollo astronauts did.

But nor is it thin enough to allow you to just land with rockets

as they do on the moon. It's a real problem, and the first to crack it,

as you say, were the Vikings.

But selecting a landing site for the two Viking craft proved difficult.

They needed as flat an area as possible,

clear of any possible hazard.

So let's begin by seeing what would happen

if Viking came down in a permafrost area.

You can see it would put the spacecraft completely out of action.

In the end, both Viking craft landed safely in July 1976.

Touchdown, we have touchdown.

APPLAUSE AND CHEERING

We have, of course, landed on the surface of Mars

and taken pictures, both immediately after landing and again since then.

And the first pictures to come back were startling.

This is Mars.

Incredible pictures sent back from Viking,

showing a red, rock-strewn landscape under a pink sky.

The detail is absolutely amazing

and these pictures would have seemed science fiction, not so long ago.

Let me now show you the first picture received

from the Martian surface itself.

There we see the rocky landscape

and we realise how fortunate and skilful it was

that Viking came down safely.

There we can see the landing pad

and we were discussing this in our last programme,

before Viking came down,

when we weren't sure whether the landing would be successful.

Well, it has been, Viking is now standing in the plain of Chryse

and it's sending back information at this moment.

I was impressed, when looking at this superb panoramic view,

which I think is the most amazing picture sent back yet.

Just look at the detail upon that.

But now, coming into view,

we can see things that look remarkably like sand dunes.

I don't think they can be anything else. Would you agree, Geoff?

Those are beautiful sand dunes with the wind coming from the left

across the picture producing very nice streaking and sharp edges.

Quite characteristic of sand dunes.

Viking is now standing on the Martian surface.

It will not come back or ever move again.

All it can do is send back information.

We've got to wait a long time

until we've got a probe which can go to Mars and bring back samples.

That lies in the next decade or possibly the decade after that.

Well, that didn't happen. No sample-and-return probe.

It hasn't happened even yet. But don't forget the Viking orbiters.

They went round and round Mars, sending back priceless data,

particularly about those polar caps.

The orbiters are often overshadowed by the landers

which get all the glamorous attention.

But they looked closely at the polar caps,

these white areas that we'd seen wax and wane

with the Martian seasons in the telescope.

The question was, what kind of ice is this?

-What are the polar caps made of?

-Thin layers of carbon dioxide ice?

A thick layer of carbon dioxide ice? Well, Viking told us.

The startling thing that's happened has been this northern polar cap,

being composed of water vapour and not the carbon dioxide ice.

This is staggering. When you look at the north polar cap,

it gives the impression of being water ice,

and we now believe that that is what it is - an ice cap.

The water that's been found above the ice cap

is about 20 times what we found at the equator,

and the surface temperature is about 20-30 degrees too high

for CO2 ice to form.

We're quite sure that we're looking at a layer of water ice.

The fact that the polar caps really were water ice

made the chances of life there decidedly brighter

and we sent something to find out.

That's right, the Viking landers made an audacious attempt to look

for signs of life at their landing sites.

It was a long shot and I'm not sure what people expected to find,

but they didn't expect the results they got.

What they were looking for were the types of chemical reaction

you expect if you have very simple life in the soil.

We're not talking aliens or plants, we're talking bacteria.

They found some unusual chemical reactions.

But what was missing were any of the building blocks of life,

none of the complicated molecules we'd expect, no organics.

So we have this mysterious picture left at the end of the Viking mission

where something unusual is happening in the Martian soil

but who knows what it is.

After Viking there was a surprising hiatus - probes going elsewhere,

and I think Mars was rather pushed into the background.

And then, in 1997, back to Mars with Pathfinder and Sojourner.

Pathfinder came down in July 1997,

in the region do Ares Vallis, thought to be an old flood plain,

which indeed it is, there's various rocks.

Pathfinder sent back pictures and the little Sojourner rover

crawled around, inspecting and analysing the rocks.

It sent back some amazing data.

Sojourner went around analysing with its x-ray instrument

the chemistry of the surrounding rocks.

You can see in this vertical picture of the site,

you can see a large boulder, top-right,

with Sojourner jammed up against it, sticking out its snout,

analysing that rock for its chemical components.

One of the first things it showed was that on Mars,

we not only have basaltic lavas like many on Earth,

but rocks called andesite which are chemically different.

This was the first new information we got.

Pathfinder and Sojourner were the first of the new wave

of Martian exploration.

They were followed by Mars Global Surveyor, which went into orbit

in September 1997 and lasted for almost a decade.

'We have ignition and lift-off of a delta-two rocket

'carrying NASA on an odyssey back to Mars.'

It was quickly followed by Odyssey which detected

the signatures of large volumes of water ice under the soil.

Not just under the polar caps, but down towards the equator too.

And next, Mars Express.

This was the European mission,

most famous in the UK as Beagle's parent mission.

Beagle didn't make it down to the surface intact,

or at least never told us if it did.

But Mars Express has been a great success,

because it discovered water again,

it looked at the polar caps and confirmed there was water down there,

but it also gives us the ability to see Mars in three-dimensions.

It has a stereo camera.

So you can produce 3-D maps of the surface

and go flying around the surface of some of the great valleys of Mars.

This is a stunning legacy from Mars Express which is still working well.

To my mind, all these were eclipsed by those two splendid rovers,

Spirit and Opportunity. Spirit was the first.

It landed on Mars in 2004,

in the crater Gusev which is an ancient lake.

And we know that because of the work Spirit has done.

These rovers were supposed to last for 90 days,

that was the warranty, and yet they've both lasted

more than five Earth years on the surface of the planet.

It's an incredible achievement.

The rovers were designed to look for clues

to tell us what the environment was like.

I never liked the attitude that we were going there to try

-to find evidence of water. That's wrong.

-That's not science.

Well, Mars is what Mars is.

Our job was to find out what Mars was like.

If Mars has never had water at these two sites, so be it.

Spirit landed successful, got off the lander fine,

and everything worked but we landed on lava.

I believe there were sediments laid down in a lake in that crater

but a lot can happen in three or four billion years

and we found there were lavas that were deposited on top of them.

And that was what Spirit landed on,

so we came looking for evidence of water and we found volcanic rocks.

Opportunity, on the other hand, rolled to a stop

inside a little 20-metre diameter impact crater.

We opened our eyes and the first thing we saw, seven metres away,

in the wall of the crater, was this outcrop of layered bedrock.

And within weeks, we drove to it,

found out that it was largely made of sulphate salts.

We found ripples, evidence for water, all of that.

It all happened in six weeks, it was remarkable.

16-17 months later, we're sitting here and the rovers are working well.

They're working extraordinarily well.

The thing that we thought was going to kill them

was dust on the solar arrays.

Mars is a very dusty place, dust is in the atmosphere,

it settles out of the atmosphere, it coats everything.

The day that Spirit landed,

the solar arrays were putting out 900 watt-hours of power.

That's enough power to run a 100-watt light bulb for nine hours.

As the dust built up,

it went down and down and we got down to about 350 watt-hours.

We think that death is about at 250. So it was getting close to the end.

And then, one glorious day, we got hit by this gust of wind.

It was just a blast of wind, nothing more than that.

Cleaned off the solar arrays.

As of two days ago,

Spirit was producing more solar power than the day we landed.

Because the wind cleaned it off and the sun is in a more

-favourable part of the sky right now.

-You're into Martian summer.

Yes, that's right.

We have so much electrical power on Spirit right now,

we have to shut her down for about two hours every afternoon

-to keep from overheating.

-Wow.

-Ha-ha-ha!

When I next caught up with Steve, a year later,

Opportunity had arrived at a breathtaking new site -

Victoria crater.

We spotted Victoria as a target the night we landed.

There was this monstrous crater.

800 metres in diameter, we had no idea how deep it was.

It turns out it was 75-metres deep.

I remember us joking that wouldn't it be cool if we had landed there!

Never thinking that we'd have the chance to drive that far.

But after 21 months of struggling across the dunes and the drifts,

we finally arrived at the rim of Victoria crater

and the place is spectacular.

What sticks in my mind is this incredible image of Opportunity from above.

Yes, that was very special. This marvellous camera called High-Rise

on the Mars Reconnaissance Orbiter spacecraft,

was turned on and operated really for the first time at Mars.

The resolution of that camera is phenomenal,

about 30 centimetres-per-pixel. So you could see the rover.

-And you could see the rover tracks.

-You could see the rover itself,

you could see the high-gain antenna on the rover deck.

It's phenomenal. And that image...

It's hard to describe, um...

My reaction when I saw it was just,

it was so good to see the rover again.

If you thought that was impressive,

Mars Reconnaissance Orbiter had another trick up its sleeve

as it prepared for NASA's next probe, Phoenix.

Phoenix was going to touch down in the Martian arctic,

but MRO managed to capture an image, not of Phoenix on the surface,

though we got that later, but of Phoenix on the way in.

So, this is the Phoenix probe hanging below its parachute

as it's descending towards the surface of Mars,

captured by MRO in orbit looking down on the scene.

I think this photo is one of the most stunning technological achievements

-that the Space Age has ever produced.

-It must be.

Now, Phoenix was different. It was not a rover, it was a lander.

It came down, it stayed where it was and had various tasks.

In particular, looking for underground ice.

Each succeeding mission had got us closer to Martian water,

but what we really wanted to do was sample it directly,

and this was Phoenix's mission.

-Touchdown signal detected!

-CHEERING

When we got to Mission Control in Arizona, it had been successful.

We're doing well. We're meeting our goals, we're on-track

and one of the greatest thrills was looking back under the lander

and seeing the pressers had cleaned off the ice layer.

We'd been told there was ice from the orbiters.

The theory says it's going to be down five centimetres,

and we look underneath and the thrusters had done our job for us!

Even before you'd started digging, you knew there was ice there.

We didn't have to dig an inch, and yet,

we can't reach that ice cos the struts under the lander prevent

the arm from going under there. So it's there but we can't touch it!

Oh, that's a steep back wall, isn't it?

And that really did dig in...

-..at the front there...

-Uh-huh.

When I returned to Mission Control a few months later,

Phoenix was already feeling the chill of the harsh arctic winter.

Temperatures have been dropping. During the summer,

the warmest part of the day was maybe -20 degrees centigrade.

Now it's down to -30, -35 and the nights are getting very cold.

It could be -110, and it's heading down to -130.

That will be the temperature throughout the entire day in the winter, -130.

Just a few short months after that visit to Mission Control,

Phoenix's life was over, as it was encased in the winter ice cap.

Like its predecessors, it had given us one piece of the Martian puzzle

and we certainly know much more now than we did in the days

when the first spacecraft flew past the red planet.

But the really big question remains unanswered.

Is there life hiding somewhere on Mars?

Well, Phoenix is still there and the other probe we sent to Mars.

They'll stay there quite placidly. In 50 years' time, what will happen?

Will there be bases on Mars? Will there be cricket on Mars?

Time will tell.

On Mars, bowlers have to contend not just with the lower gravity,

but with the lower atmospheric pressure as well.

It makes it hard to get a swing on the ball,

though it is travelling much faster when it reaches the batsman.

The down side is that if the batsman connects with it,

it's really easy for him to hit a six!

-COMMENTATOR:

-'A fine shot for four runs, and no mistake.'

Good night.

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