Finding Life Beyond Earth Page #5

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close enough to the equator that

even under today's conditions,

there's a small chance

of liquid water and life.

NARRATOR:

If probes were to find

liquid water on Mars,

it would be

an extraordinary discovery,

but water alone

does not equal life.

STEVE SQUYRES:

There is a better match today

between conditions that we know

can support life on Earth

and conditions that we know

either exist or once existed

on other planets

within our solar system.

But that still begs

the question,

what conditions are required

for life to emerge

in the first place?

How does this process

of genesis,

life emerging from nonliving

material, take place?

Are the conditions

that once existed on Mars

adequate for that?

We don't know.

We simply don't know.

NARRATOR:

So how could scientists find out

if life is possible

below Mars' surface?

One recent discovery, still open

to debate, provides a clue.

Measuring wavelengths

of infrared light,

a NASA telescope on Earth

detects something mysterious

in Mars' atmosphere--

evidence of methane gas.

It's an intriguing find.

Some methane gas on Earth

is produced by geological

activity like mud volcanoes,

but most of the methane found

in our atmosphere

is a waste product

generated by microorganisms.

Methane has a very interesting

connection to life in many ways.

It could be a product of life.

It could be something that life

has made, evidence of life.

GREEN:

Well, the discovery of methane

was really one of the fabulous

discoveries that have come out

just in the last several years.

NARRATOR:

New observations by the Keck

telescopes suggest

that certain areas on Mars are

releasing thousands of tons

of methane gas every year.

So where is the methane

coming from?

It's seasonal.

We seem to have

more methane emitted

during the summer season on Mars

than we do at any other time.

NARRATOR:

There is not enough data yet

to tell scientists what is

producing the methane.

But whatever the source,

it's a tantalizing clue

that could change our

understanding of Mars.

Methane could be biological,

which would be amazing,

or it would indicate

that there's some geological

process making methane,

which would also be amazing

because that would indicate

that Mars is an active world.

NARRATOR:

To find out, NASA is going back

to the red planet.

This time, one of its key

missions is to search

for organic molecules,

the building blocks of life.

If we were to find

organic molecules on Mars

and confirmed that they're

actually from Mars

and not something we brought

along, wow!

That would be spectacular.

NARRATOR:

If found, it might mean that all

three ingredients for life

are here,

opening the possibility

that life could take hold.

Of course

we're all human, right?

And we want certain things.

Nobody wants us

to be alone, right?

But it's important in science

to maintain an open mind.

NARRATOR:

To find organic molecules,

NASA is launching a Mars rover

the size of a compact car

named Curiosity.

GREEN:

Curiosity will be

our first great chance,

I believe,

to look for life on Mars.

NARRATOR:

Curiosity holds

the most advanced set

of science instruments yet sent

to the planet.

It will zap, grind

and bake Martian rocks

and use spectroscopic analysis

to reveal if the samples contain

any of the chemical ingredients

for life.

It is not just a geologist,

it's an astrobiologist.

It can look at rocks

and everything else around it

in ways that we've never looked

at the material before.

NARRATOR:

Even with an advanced set

of instruments,

finding organic molecules will

still be a challenge.

SQUYRES:

It's going to be

a tricky problem.

There are lots of processes that

can destroy organic molecules.

Radiation from space

can destroy them.

Oxidizing compounds

in the Martian atmosphere

can destroy them.

So you're looking

for organic molecules

that have somehow been protected

from the Martian environment

for a while.

NARRATOR:

And the bar is set even higher,

because Curiosity will search

for specific organic compounds

that are the product

of living things,

evidence that life

once existed here.

That's what Jennifer

Eigenbrode's experiment

is designed to uncover.

EIGENBRODE:

Organic molecules tell a story

about where they came from

and what happened to them,

and that's the story that I'm

trying to uncover in Mars rocks.

GREEN:

That experiment may very well

change our impression of Mars

as a lifeless body

and change it to harboring life.

NARRATOR:

If Curiosity turns up

any evidence

that life once existed on Mars,

it will have enormous

implications.

If rightere in our own little

solar system life started twice,

then it would say that life

is just everywhere.

NARRATOR:

Curiosity and other missions

may one day reveal

if life once existed

on places like Mars

and if it still exists today.

But even if scientists

ultimately conclude

that there is no life

on the planets closest to Earth,

it doesn't mean

it's not out there.

Beyond Mars are other worlds

waiting to be explored...

The distant moons that orbit

the giant planets Jupiter

and Saturn...

Moons just as strange as

the orange-shrouded Titan...

One pockmarked

with hundreds of volcanoes...

Others glistening with ice and

covered in mysterious lines...

And one tiny moon

etched with deep fissures.

GREEN:

We're now finding when we look

at these giant planets

and their moons

that they are almost like mini

solar systems in themselves.

NARRATOR:

Probes are making discoveries

on these moons

that are changing

our understanding

of where life can exist.

They're finding evidence

of new sources of energy,

hidden oceans of liquid water,

and organic molecules

blasting into space.

And far beyond these worlds,

scientists are exploring

entire new solar systems

around other stars.

GEOFF MARCY:

Surely billions,

hundreds of billions of the

Earth-like planets out there

have the conditions suitable

for life.

NARRATOR:

As scientists race to explore

these distant places

with more and more advanced

technologies,

they are finding that

the conditions for life

are not exclusive to Earth

and that the natural forces

set in motion here

might be active elsewhere

in our galaxy and beyond.

NARRATOR:

Are we alone in the universe?

This age-old question

is yielding some

provocative new answers.

Recent discoveries suggest

that the conditions for life

might be more prevalent

than ever imagined.

JIM GREEN:

Science fiction didn't tell us

in any way, shape, or form

what we're finding out now.

NARRATOR:

Missions to our neighbor Mars

are revealing evidence

that water, a key ingredient

for life, may be present.

CHRIS McKAY:

Mars has lots of water.

Mars is an ice cube covered

with a layer of dirt.

NARRATOR:

And probes are finding

the essential chemical

building blocks of life

in unexpected places.

DANNY GLAVIN:

Literally the seeds of life

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