All language subtitles for Cosmos - 05

SAGAN:
Martians.

Why so many speculations
and fantasies about Martians...

...rather than Saturnians, say,
or Plutonians?

Because Mars seems,
at first glance, very Earth-like.

It's the nearest planet
whose surface we can see.

There are polar icecaps,
drifting white clouds...

...raging dust storms,
seasonally changing patterns...

...even a 24-hour day.

It's tempting to think of it
as an inhabited world.

Mars has become
a kind of mythic arena...

...onto which we've projected
our earthly hopes and fears.

The most tantalizing myths
about Mars have proved wrong.

So a few people have swung
to the opposite extreme...

...and concluded that
the planet is of little interest.

They've begun to sing
blues for the Red Planet.

But the real Mars is
a world of wonders.

Its future prospects are
far more intriguing...

...than our past apprehensions
about it.

In our time, we have sifted
the sands of Mars...

...established a presence there...

...and fulfilled a century of dreams.

The most startling dream of Mars
was that of H.G. Wells...

...who in 1897 wrote
The War of the Worlds.

NARRATOR: "No one would have believed
in the end of the 19th century...

...that this world was being
watched keenly and closely...

...by intelligences
greater than man's...

...and yet as mortal as his own.

As men busied themselves
about their various concerns...

...they were scrutinized
and studied...

...perhaps almost
as narrowly as a man...

...with a microscope
might scrutinize...

...the transient creatures
that swarm and multiply...

...in a drop of water.

With infinite complacency,
men went to and fro over this globe...

...about their little affairs...

...serene in their assurance
of their empire over matter.

It's possible that the infusoria
under the microscope do the same.

(CHILDREN SINGING)

No one thought of
the older worlds of space...

...as sources of human danger...

...or thought of them only to dismiss
the idea of life upon them...

...as impossible or improbable.

(CLAPPING)

It is curious to recall...

...some of the mental habits
of those departed days.

At most, terrestrial men fancied...

...there might be other men upon Mars,
perhaps inferior to themselves...

...and ready to welcome
a missionary enterprise.

Yet across the gulf of space...

...intellects vast
and cool and unsympathetic...

...regarded this Earth
with envious eyes...

...and slowly and surely
drew their plans against us."

(CHEERING)

SAGAN: Wells' novel captured
the popular imagination...

...in the late Victorian era.

This was a time when
the automobile was a novelty...

...when the pace of life...

...was still determined
by the speed of the horse.

Into this world, Wells introduced
an interplanetary fantasy...

...with spaceships, ray guns
and implacable aliens.

These were original
and disquieting possibilities.

The Martians of H.G. Wells...

...were not merely minor variations
on a human theme.

Instead, they were
the evolutionary product...

...of a totally alien environment.

Forty years later,
this fantasy was still able...

...to frighten millions
in war-jittery America...

...when it was dramatized for radio
by the young Orson Welles.

A few years before
The War of the Worlds was published...

...another, quite different
vision of Martians...

...was forming in the mind
of a wealthy Bostonian...

...named Percival Lowell.

The Martians of H.G. Wells
were a way for the novelist...

...to examine contemporary society
through alien eyes.

But the Martians of Percival Lowell
were, he believed...

...very real.

It was here that
the most elaborate claims...

...in support of life on Mars
were developed.

Lowell dabbled in astronomy
as a young man.

He went off to Harvard.

He had a semiofficial
diplomatic appointment to Korea...

...and otherwise engaged
in the usual pursuits...

...of the wealthy for his time.

But his lifelong love...

...was the planet Mars.

Lowell was electrified...

...by the announcement in 1877...

...by an Italian astronomer,
Giovanni Schiaparelli...

...of canali on Mars.

Schiaparelli had reported...

...during a close approach
of Mars to the Earth...

...an intricate network of
single and double straight lines...

...crisscrossing
the bright areas of Mars.

Now, canali in Italian
means "channels" or "grooves"...

...but it was promptly translated
into English as canals...

...a word which understandably has...

...a certain implication
of intelligent design.

A Mars-mania swept through
Europe and America...

...and Percival Lowell found
himself caught up in it.

In 1892, his eyesight failing...

...Schiaparelli announced
he was giving up observing Mars.

Lowell resolved
to continue the work.

(ROOF CREAKS)

He wanted
a first-rate observing site...

...undisturbed by clouds
or city lights...

...and marked by good seeing.

"Seeing" is the astronomer's term
for a steady atmosphere...

...through which the shimmering
of an astronomical image...

...in the telescope is minimized.

Lowell built his observatory
far away from home...

...on Mars Hill,
here in Flagstaff, Arizona.

Lowell sketched
the surface features of Mars...

...and particularly the canals,
which mesmerized him.

Now, observations of this sort
aren't easy.

You put in long hours
at the telescope...

...in the chill of the early morning.

Most of the time,
the seeing is crummy.

When the seeing is bad...

...the image of Mars
blurs and distorts...

...and you have to ignore
what you've observed.

But occasionally the image steadies
and the features of the planet...

...marvelously flash out at you.

You must then remember
what you've seen...

...and accurately commit it to paper.

You must put
your preconceptions aside...

...and with an open mind,
set down the wonders...

...that Mars holds in store for us.

This is Percival Lowell's
own notebook.

Here's what he thought he saw.

Bright and dark areas,
a hint of a polar cap...

...and canals.
Lots and lots of canals.

Lowell believed...

...that he was seeing
a globe-girdling network...

...of great irrigation canals...

...carrying water
from the melting polar caps...

...to the thirsty inhabitants
of the equatorial cities.

He believed
the planet was inhabited...

...by an older and wiser race...

...perhaps very different from us.

He believed...

...that the seasonal changes
in the dark areas...

...were due to the growth
and decay of vegetation.

He believed that
the planet was Earth-like.

All in all, he believed too much.

Lowell's Martians were a dying race.

Their once-great cities
had fallen into ruins.

Lowell believed that
the Martian climate was changing...

...that the precious water
was trickling away into space...

...that the planet
was becoming a desert world.

The canals, he thought,
were a last desperate measure...

...a heroic engineering effort
to conserve the scarce water.

But their technology, although
far more advanced than ours...

...was inadequate to stem
a planetary catastrophe.

The most serious contemporary
challenge to Lowell's ideas...

...came from an unlikely source:

The biologist Alfred Russel Wallace...

...co-discoverer of evolution
by natural selection.

Wallace correctly showed
that the air on Mars...

...was much too cold and thin...

...to permit the existence
of liquid water.

He wrote that
"only a race of madmen...

...would build canals
under such conditions."

Lowell's Martians
were benign and hopeful...

...even a little godlike...

...very different
from the malevolent menace...

...posed by H.G. Wells and Orson
Welles in The War of the Worlds.

Both sets of ideas passed
into the public imagination...

...through Sunday supplements
and science fiction...

...and excited generations
of 8-year-olds into fantasizing...

...that they themselves
might one day voyage...

...to the distant planet Mars.

I remember reading
with breathless fascination...

...the Mars novels
of Edgar Rice Burroughs.

I journeyed with John Carter...

...gentleman adventurer
from Virginia...

...to Barsoom, as Mars
was known by its inhabitants.

Wandering among the beasts
of burden called thoats...

...winning the hand of
the lovely Dejah Thoris...

...Princess of Helium...

...and befriending
a 10-foot-high green fighting man...

...named Tars Tarkas...

...as the moons of Mars
hurtled overhead...

...on a summer's evening on Barsoom.

It aroused generations
of 8-year-olds...

...myself among them...

...to consider the exploration of
the planets as a real possibility...

...to wonder whether we ourselves
might one day venture...

...to the distant planet Mars.

John Carter got to Barsoom
by standing in an open field...

...spreading his hands
and wishing hard at Mars.

I can remember spending
many an hour in my boyhood...

...arms resolutely outstretched...

...in an open field in twilight...

...imploring what I believed
to be Mars to transport me there.

It never worked.

There had to be some better way.

And there was.
The real road to Mars was opened...

...by a boy who loved skyrockets.

(BAND PLAYS)

Fourth of July celebrations
in New England...

...are much the same today
as they were in the 1890s.

Then, as now, the highlight
of the day's festivities...

...was a rousing fireworks display.

That was the part that
Robert Goddard liked the best.

By the time he was 16,
he was launching his own rockets.

He wrote in his diary:

"July 4, 1898:

Fired cannon
and firecrackers all day.

In evening, had five rockets."

- You gonna light it now?
- Yes, I am.

Wow!

That same year...

...The War of the Worlds was being
serialized in the Boston Post.

Goddard eagerly read every word.

The Boston newspapers
were also reporting...

...intriguing conjectures
by a Professor Lowell...

...whose lectures
Goddard would later attend.

The images of Mars spun
by Wells and Lowell...

...beguiled the young Goddard...

...and at age 17...

...on October 19, 1899...

...they crystallized
into an overwhelming vision...

...that provided the direction
and purpose of his life.

From the high branches...

...of an old cherry tree
on his family's farm...

...Goddard saw a way to do more
than just speculate about Mars.

Before anyone had ever flown
in an airplane...

...or listened to a radio...

...Goddard decided
to invent a machine...

...that would voyage
to the planet Mars.

For the rest of his life, he was
to commemorate that October day...

...as his anniversary day...

...the birthday of his great dream.

By the 1920s, after years of
studying physics and engineering...

...he was experimenting
with liquid fuel rockets.

In order to build a rocket capable
of reaching high altitudes...

...Goddard had to create the principles
of an entirely new technology.

He invented the basic components...

...that propel, stabilize...

...and guide the modern rocket.

It was painstaking and difficult work.

But Goddard took
the many setbacks in stride.

He sifted the wreckage
of each experiment...

...for clues to guide the next.

Constantly refining old techniques
and inventing new ones...

...he gradually raised the rocket
from a dangerous toy...

...and set it on its way to becoming
an interplanetary vehicle.

Goddard died in 1945...

...before a rocket had ever
left the planet Earth.

Although Mars always
remained his objective...

...Goddard knew that such a goal
would be ridiculed.

In public he advocated
the more modest objective...

...of flying to the moon.

Those boyhood dreams of voyages
to the moon and Mars...

...shared by Goddard
with his contemporary...

...a Russian scientist named
Konstantin Tsiolkovsky...

...were fulfilled only
a few decades after their deaths.

But as it turned out, the first
planet to be explored by rocket...

...was the Earth.

Now, imagine yourself a visitor...

...from some other
and quite alien planet.

You approach the Earth
with no preconceptions.

Is the place inhabited?
At what point can you decide?

When we look at the whole Earth,
there are no signs of life.

We must examine it more closely.

If there are intelligent beings,
maybe they create structures...

...which can be seen at
a resolution of a few kilometers.

Yet at this level of detail...

...even a great river valley
seems utterly lifeless.

There is no sign of life...

...intelligent or otherwise
in Washington, D. C...

...or Moscow...

...or Tokyo...

...or Peking.

If there are intelligent beings,
they have not much modified...

...the landscape into geometrical
patterns at kilometer resolution.

But when we improve
the resolution tenfold...

...when we see detail
as small as 100 meters across...

...the size of a football field...

...the situation changes.

Many places on Earth seem suddenly
to crystallize out...

...revealing an intricate pattern
of straight lines...

...squares, rectangles and circles.

Canals, roads,
circular irrigation patterns...

...all suggest intelligent life
with a passion...

...for Euclidean geometry
and territoriality.

On this scale,
intelligent life can be discerned.

Boston...

...and Washington...

...and New York.

At 10-meter resolution, we also
discover that the Earthlings...

...like to build up.

At twilight or night,
other things are visible:

Oil well fires in the Persian Gulf...

...or the bright lights
of large cities.

At a meter resolution,
we make out individual organisms:

Seals on ice floes...

...or people on skis.

Intelligent life on Earth
first reveals itself...

...through the geometric regularity
of its constructions.

If Lowell's canal network existed,
the conclusion that...

...intelligent beings inhabit
that planet might be compelling.

But there is no canal network.

Our unmanned spacecraft
have examined Mars...

...with 1000 times more detail...

...than any fleeting glimpse available
through Percival Lowell's telescope.

There is no question that his Martian
canals were of intelligent origin.

The only question was...

...which side of the telescope
the intelligence was on.

Where we have strong emotions,
we are liable to fool ourselves.

Yet even without the canals,
the exploration of Mars evokes...

...the kind of rapture that...

...Columbus or Marco Polo
must have felt.

We see many impact craters...

...but we find no canals.
None at all.

There are fault lines
in the surface...

...and complex patterns
of ridges and valleys...

...but they're all far too small
and in the wrong places...

...to be Lowell's canals.

And they don't seem
to be manufactured.

There are many signs of water.

Ancient river valleys wind
their way among the craters.

Nergal Valley, named
after the Babylonian war god...

...is 1000 kilometers long
and a billion years old.

There seems to have been a time...

...when Mars was warmer
and wetter than it is today.

I wonder if life ever arose...

...in the muddy backwaters
of these great river systems.

The waters flowed at the same time...

...that the great volcanoes
of the Tharsis Plateau were made.

Before the present continents
of Earth were formed...

...it was a very lively epoch on Mars.

Equally old is the Mariner Valley...

...a strange, vast, mist-filled chasm.

If it were on Earth, it would stretch
from New York to Los Angeles.

Landslides and avalanches
are slowly eroding its walls...

...which collapse
to the floor of the valley.

There, the winds remove
the particles...

...and create immense
sand dune fields.

Signs of high winds are all over Mars.

Often craters have,
trailing behind them...

...long streaks of bright or dark
material, blown out by the winds...

...natural weathervanes
on the Martian surface.

For the sand to be blown about
in the thin Martian atmosphere...

...the winds have to be fast...

...sometimes approaching
half the speed of sound.

But some of the patterns
are so odd and intricate...

...that we cannot be sure
they're caused by windblown sand.

And there are other strange markings:

Furrowed ground, almost resembling...

...a giant plowed field
a billion years old...

...and one of the strangest
features on Mars...

...the pyramids of Elysium...

...10 times taller
than the pyramids of Egypt.

Perhaps they're only mountains
sculpted by the fierce winds...

...but perhaps they're something else.

How marvelous it would be
to glide over the surface of Mars...

...to fly over Olympus Mons...

...the largest known volcano
in the solar system.

The surface area of Mars
is exactly...

...as large as
the land area of the Earth.

It will be a long time before
this planet is thoroughly explored.

The only canal of Percival Lowell
that corresponds to anything real...

...is Mariner Valley.

5000 kilometers long...

...it's a little hard
to miss even from Earth.

The Grand Canyon
of Arizona would fit...

...into one of its minor tributaries.

Someday we will careen
through the corridors...

...of the Valley of the Mariners.

To skim over
the sand dunes of Mars is...

...as yet, only a dream.

But we have, in fact...

...sent robot emissaries to Mars.

Their names are Viking 1...

...and Viking 2.

The problem was where to land them.

We knew that the volcanoes
of Tharsis were too high.

The thin Martian atmosphere
would not...

...support our descent parachute.

The great Mariner Valley was
too rough and unpredictable.

The polar caps were too cold...

...for the lander's nuclear
power plant to keep it warm.

There were fascinating places
that were too high...

...or too windy
or too hard or too soft...

...or too rough or too cold.

We worried about the safety
of every landing site.

Perhaps we were too cautious.

Eventually we selected two places.

One, optimistically named Utopia...

...for Viking 2...

...and another,
8000 kilometers away...

...not far from the confluents
of four great channels...

...a landing site for Viking 1...

...called Chryse...

...Greek for "the land of gold."

And so, after a voyage
of 100 million kilometers...

...on July 20, 1976...

...Viking 1 landed right on target...

...in the Chryse Plain.

It was less than 80 years
since Robert Goddard...

...had his epiphanic vision...

...in a cherry tree in Massachusetts.

After hibernating for a year
during its interplanetary passage...

...Viking reawakened on another world.

The first thing it did
was to call home...

...reporting a safe arrival.

It began to rouse itself...

...according to instructions
memorized earlier.

First, it put out a finger
to test the Martian winds.

Then, flexing its arm...

...it flung off a protective glove.

Next, Viking prepared
to sniff the air...

...and taste the soil.

Finally...

...it opened its eyes for a look
at its new surroundings.

(WHIRRING)

Viking's first picture assignment
was to photograph its own foot.

In case it were to sink
into Martian quicksand...

...we wanted to know about it
before it disappeared.

Back on Earth, we waited
breathlessly for the first images.

Viking painted its picture
in vertical strokes, line by line...

...until, with enormous relief,
we saw the footpad...

...securely planted
in the Martian soil.

This was the first image
ever returned from the surface of Mars.

The cameras on each
Viking lander revealed...

...a kind of rocky desert.

Beyond the lander itself...

...we saw for the first time...

...the landscape of the Red Planet.

It didn't look like an alien world.

There were rocks and sand dunes...

...and gently rolling hills
as natural and familiar...

...as any landscape on Earth.

Forever after, Mars would be a place.

We found that the Martian air
was less than 1% as dense as ours...

...and made mostly of carbon dioxide.

There were smaller amounts
of nitrogen, argon...

...water vapor and oxygen.

There was almost no ozone.
So the surface wasn't protected...

...from the sun's ultraviolet light
as it is on Earth.

On the warmest days,
it was distinctly chilly...

...and every night the temperatures
plunged to 100 below.

In winter, the surface was dusted
with a thin layer of frost.

The landing sites were chosen
because they were safe and flat.

Even so, Viking revolutionized
our knowledge...

...of this rusty world.

I would, of course, have been
surprised to see...

...a grizzled prospector emerge
from behind a dune...

...leading his mule.

Yet the idea seemed
strangely appropriate.

But at least while we were watching...

...no prospector wandered by.

We studied with exceptional care
each picture the cameras radioed back.

But there was no hint
of the canals of Barsoom...

...no sultry princesses...

...no 10-foot-tall
green fighting men...

...no thoats, no footprints...

...not even a cactus
or a kangaroo rat.

Perhaps there was life
inside the rocks...

...or under the ground.

If so, it had left no traces.

For most of its history,
the Earth had microbes...

...but no living things
big enough to see.

Perhaps the same is true for Mars.

The Viking lander is a superbly
instrumented and designed machine.

It extends human capabilities
to other and alien landscapes.

By some standards, it's about
as smart as a grasshopper.

By others, only as intelligent
as a bacterium.

There's nothing demeaning
in these comparisons.

It took nature hundreds of millions
of years to evolve a bacterium...

...and billions of years
to make a grasshopper.

With only a little experience
in this business...

...we're getting pretty good at it.

In both landing sites...

...in Chryse and Utopia...

...we've begun to dig
in the sands of Mars.

On a very small scale,
such trenches...

...are the first human engineering
works on another world.

The robot arm
retrieves soil samples...

...and deposits them
into several sifters.

Then the soil is carried
to five experiments:

Two on the chemistry of the soil...

...and three to look
for microbial life.

The Viking biology experiments
represent a pioneering first effort...

...in the search for life
on another world.

The results are
tantalizing, annoying...

...provocative, stimulating...

...and deeply ambiguous.

By criteria established
before a launch...

...two of the three Viking
microbiology experiments...

...seem to have yielded
positive results.

First, when Martian soil samples
are mixed together...

...with an organic soup from Earth...

...something in the soil
seems to have broken food down...

...almost as if there were
little Martian microbes...

...which metabolized, enjoyed...

...the soup from Earth.

Second, when gases from Earth...

...were mixed together
with Martian soil...

...something seems to have chemically
combined the gases with soil...

...almost as if there were little
Martian microbes capable...

...of synthesizing organic matter
from atmospheric gases.

But the situation is complex.

Mars is not the Earth.

As the legacy of Percival Lowell
reminds us, we're liable to be fooled.

Perhaps the ultraviolet light
from the sun...

...strikes the Martian surface...

...and makes some chemical
which can oxidize foodstuffs.

Perhaps there is some catalyst
in the soil...

...which can combine atmospheric gases
with the soil...

...and make organic molecules.

The red sands of Mars
were excavated...

...seven times at
the two different landing sites...

...as distant from each other
as Boston is from Baghdad.

Whatever was giving these results
was probably all over Mars...

...but was it life, or just
the chemistry of the soil?

Studies suggest that a kind of clay
known to exist on Mars...

...can serve as a catalyst to
accelerate in the absence of life...

...chemical reactions which
resemble the activities of life.

It may be that in the early history
of the Earth, before life...

...there were little cycles,
chemical cycles running in the soil...

...something like photosynthesis
and respiration...

...which were then incorporated
by biology once life arose.

There may be life elsewhere than
in the two small sites we examined.

Or perhaps there's life
of a different sort all over Mars.

Life is just a kind of chemistry
of sufficient complexity...

...to permit reproduction
and evolution.

I wonder if we'll ever find
a specimen of life based...

...not on organic molecules...

...but on something else,
something more exotic.

The Viking experiments found
that the Martian soil is not...

...loaded with organic remains...

...of once living creatures.

Maybe the surface's reactive chemistry
has destroyed organic molecules...

...molecules based on carbon.

Or maybe there's no life on Mars...

...and all Viking found
was a funny soil chemistry.

Or maybe there's life, okay...

...but it's not based on organic
chemistry as much as life is on Earth.

Personally, I don't think that's
a very likely possibility.

I'm a carbon chauvinist.
I freely admit it.

Carbon is tremendously abundant
in the cosmos...

...and it makes marvelously complex
organic molecules...

...that are terrifically
good for life.

I'm also a water chauvinist.

It's an ideal solvent
for organic molecules...

...and it stays liquid over
a very wide range of temperatures.

But sometimes I wonder,
could my fondness...

...for these materials have
anything to do with the fact...

...that I'm chiefly made up of them?

Are we carbon and water-based because
these materials were abundant...

...on the Earth at the time
of the origin of life?

Might life elsewhere be based
on different stuff?

(LIQUID GURGLES)

I'm a collection of organic molecules
called Carl Sagan.

You're a collection of almost
identical molecules...

...with a different collective label.
But is that all?

Is there nothing in here
but molecules?

Some people find that idea
somehow demeaning to human dignity.

But for myself, I find it
elevating and exhilarating...

...to discover that we
live in a universe...

...which permits the evolution
of molecular machines...

...as intricate and subtle as we.

The essence of life is not the atoms
and small molecules that go into us...

...as the way, the ordering...

...the way those molecules
are put together.

Now, we sometimes read...

...that the chemicals which make up
a human body are worth...

...on the open market, only 97 cents
or $10, or some number like that.

And it's depressing to find
our bodies valued at so little.

But these estimates are for humans...

...reduced to our simplest
possible components.

What is all this stuff in front of me?

These are exactly the atoms
that make up the human body...

...and in the right proportions too.

We're made mostly of water,
and that costs almost nothing.

The carbon is counted as coal.

The calcium in our bones is chalk.

The nitrogen in our proteins
is liquid air.

The iron in our blood
is rusty nails.

Some phosphorus
and some trace elements.

If we didn't know better...

...we might be tempted
to take all these items...

...and mix them together
in a container like this.

And stir.

We could stir all we want...

...and at the end, all we'd have
is some boring mixture of atoms.

How could we expect anything else?

The beauty of a living thing
is not the atoms that go into it...

...but the way those atoms
are put together:

Information distilled over 4 billion
years of biological evolution.

Incidentally, all the organisms
on the Earth are made...

...essentially of that stuff.

An eyedropper full of that liquid...

...could be used to make
a caterpillar or a petunia...

...if only we knew how to put
the components together.

All life on Earth is made from
the same mixture of the same atoms.

On another planet, the jars of life...

...might be filled with very
different atoms and small molecules.

But I think the life forms on many
worlds will consist, by and large...

...of the same atoms
that are popular here...

...maybe even the same big molecules.

So I don't believe we can rescue
the idea of life on Mars...

...by appealing to some
exotic chemistry.

Sometimes we hear about
possible life forms...

...in which silicon replaces carbon...

...or perhaps, liquid ammonia
replaces liquid water.

But at Martian temperatures,
there are no...

...plausible silicon-based molecules
which might carry a genetic code.

And ammonia is liquid
only under higher pressures...

...and lower temperatures.

Someday in the distant future
we might have a collection of jars...

...each containing the elementary
biochemistry of another world.

I don't know if there'll be
one labeled "Mars."

But if there is...

...I bet it will be
full of organic molecules.

There's another way to search
for life on Mars...

...to seek out the discoveries
and delights...

...which that heterogeneous
environment promises us.

One of the things that a grasshopper
can do but Viking can't...

...is move.

We landed in the dull places on Mars.

For all the solid, scientific findings
and hints which Viking provided...

...we know that there are many places
on the planet far more interesting.

What we need is a roving vehicle...

...with advanced experiments in
biology and organic chemistry...

...able to land in the safe
but dull places...

...and wander
to the interesting places.

This roving vehicle...

...was developed by the
Rensselaer Polytechnic Institute.

It has a long list of dumb things
it knows not to do.

A Mars rover hasn't got time to ask
if it should attempt a steep slope.

Radio waves traveling
at the speed of light...

...take 20 minutes
for the roundtrip to Earth.

By the time it got an answer,
it might be...

...a heap of twisted metal
at the bottom of a canyon.

A rover has to think for itself.

Imagine a rover with laser eyes
like this one...

...but packed with sophisticated
biological and chemical instruments...

...sampler arms, microscopes
and television cameras...

...wandering over
the Martian landscape.

It could drive to its own
horizon every day.

A distant feature it barely
resolves at sunrise...

...it can be sniffing and tasting
by nightfall.

Billions of people could watch
the unfolding adventure...

...on their TV sets as the rover
explores the ancient river bottoms...

...or cautiously approaches...

...the enigmatic pyramids of Elysium.

A new age of discovery
would have begun.

Most of the human species
would witness...

...the exploration of another world.

Only 80 years ago, we could come
no closer to Mars...

...than straining to see
a tiny, shimmering image...

...through a telescope in Arizona.

Now our instruments have actually
touched down on the planet.

Viking is a legacy of H.G. Wells...

...Percival Lowell, Robert Goddard.

Science is a collaborative enterprise
spanning the generations.

When it permits us to see the far side
of some new horizon...

...we remember those
who prepared the way...

...seeing for them also.

On each lander, there is a microdot
on which is written very small...

...the names of 10,000
men and women...

...responsible for Viking's
splendid achievement.

One of the names on this microdot
belonged to a friend of mine:

A remarkable microbiologist
named Wolf Vishniac.

He was the first person
to build a machine...

...to look for microbes
on another world.

His friends called it the "Wolf Trap."

It contained a liquid nutrient...

...to which Martian soil
would be added...

...and any microbes
that liked the food...

...would grow in that nutrient
medium and cloud it.

The Wolf Trap was selected
to go with Viking to Mars...

...but NASA is especially vulnerable
to budget cuts...

...and it was removed
as an economy measure.

It was a terrible blow to Vishniac.
He'd worked 12 years on it.

Others might have
stalked off the project...

...but Vishniac was a gentle
and dedicated man.

He decided instead to study the most
Mars-like environment on this planet:

The dry valleys of Antarctica,
which were long thought to be lifeless.

But Vishniac believed that if he
could find microbes growing...

...in these arid polar wastes...

...the chances of life on Mars
would improve.

So in November 1973...

...Vishniac was left
in a remote valley...

...in the Asgard Mountains
of Antarctica.

He set up hundreds of little
sample collectors...

...simple versions of the Viking
microbiology experiments.

On December 10th...

...he left camp
to retrieve some samples...

...and never returned.

He had wandered
to an unexplored area...

...apparently slipped on the ice...

...and fell more than 100 meters.

Maybe something had caught his eye...

...a likely habitat for microbes...

...or a patch of green
where none should be.

The last entry in his notebook was:

"Station 202 retrieved.
2230 hours.

Soil temperature, minus 10 degrees.

Air temperature, minus 16 degrees."

It had been a typical
summer temperature...

...for Mars.

Some of his soil samples
were later returned...

...and his colleagues discovered...

...that there is life
in the dry valleys of Antarctica...

...that life is even more tenacious
than we had imagined.

That fact may turn out to be important
for the future history of Mars.

There will be a time...

...when Mars is thoroughly explored.

What then?
What should we do with Mars?

If there is life on Mars, then I
believe we should do nothing...

...to disturb that life.

Mars, then, belongs to the Martians,
even if they are microbes.

But suppose that Mars is
in fact lifeless.

Might we in some sense be able
to live there...

...to somehow make Mars
habitable like the Earth...

...to terraform another world?

As lovely a world as Mars is...

...it poses certain problems.

There's too little oxygen,
no liquid water...

...and too much ultraviolet light.

But all that could be solved
if we could make more air.

With higher atmospheric pressures,
liquid water would become possible.

With more oxygen we could
breathe the atmosphere.

And ozone could form
to shield the surface...

...from the solar ultraviolet light.

The evidence for liquid water
suggests...

...that Mars once had
a denser atmosphere...

...which can't have all
escaped to space.

It has to be on the planet somewhere.

In subsurface ice, surely...

...but most accessibly
in the present polar caps.

To vaporize the icecaps,
we must heat them...

...preferably by covering them with
something dark to absorb more sunlight.

That thing ought to also be cheap
and able to make copies of itself.

Well, there are such things.
We call them plants.

We would need to evolve by artificial
selection and genetic engineering...

...dark plants able to survive
the severe Martian environment.

Such plants could be seeded...

...on the vast expanse
of the Martian polar icecaps...

...taking root, spreading,
giving off oxygen...

...darkening the surface,
melting the ice...

...and releasing
the ancient Martian atmosphere...

...from its long captivity.

We might even imagine a kind of
Martian Johnny Appleseed...

...robot or human...

...roaming the frozen polar wastes
in an endeavor which benefits...

...only the generations to come.

It might take hundreds
or thousands of years.

We might, then, want to carry
the liberated water...

...from the melting polar icecaps...

...to the warmer equatorial regions.

And there's a way to do it:

We would build canals.

But that's exactly what
Percival Lowell believed...

...was happening on Mars in his time.

The idea of a canal network
built by Martians...

...may turn out to be
a kind of premonition...

...because, if the planet
ever is terraformed...

...it will be done by human beings...

...whose permanent residence
and planetary affiliation...

...is Mars.

The Martians will be us.

Mars today is strictly relevant to
the global environment of the Earth.

Its antiseptic surface is
a cautionary tale of what happens...

...if you don't have an ozone layer.

Its great dust storms and the resulting
cooling of its surface...

...played a role in the discovery
of nuclear winter...

...the catastrophic climate change on
Earth predicted to follow nuclear war.

So if you didn't have an ounce
of adventuresome spirit in you...

...it would still make sense
to support the exploration of Mars.

In recent years, there's been...

...a groundswell of interest...

...in organizing the first expedition
of humans to go to the planet Mars.

We first need more robotic missions,
including rovers...

...balloons and return-
sample missions...

...and more experience
in long duration space flight.

But eventually, if all goes well...

...the interplanetary
ship or ships...

...would be constructed
in Earth orbit...

...launched on the long
journey to Mars...

...and then a landing module
would set down on the surface.

The crew would emerge...

...making the first human footfalls
on another planet.

It would be very expensive,
of course...

...although cheaper
if many nations share the cost.

The key issue in my mind is whether
the unmet needs here on Earth...

...should take priority.

But that's a question even more
appropriately addressed...

...to the military budgets...

...now $1 trillion a year worldwide.

You can buy a lot for that.

Justifications for the Mars endeavor
have been offered in terms of...

...scientific exploration...

...developing technology,
international cooperation...

...education, the environment.

Some see it as the obvious response
to the future calling.

Some even think we should go
to investigate enigmatic landforms...

...including one that resembles
an enormous human face.

Personally, I think this,
like hundreds of other...

...blocky mesas there...

...is sculpted by
the high-speed winds.

But if we're going anyway,
there's no harm in taking a look.

A remarkably diverse group
of American leaders...

...has endorsed the Mars goal.

I imagine the emissaries from Earth...

...citizens of many nations...

...wandering down an ancient
river valley on Mars...

...trying to understand
how a quite Earth-like world...

...was converted
into a permanent ice age...

...and looking for signs of
ancient life along the river banks.

In the long run...

...the significance of such a mission
is nothing less...

...than the conversion of humanity
into a multiplanet species.