All language subtitles for Universe - S01E01 Aliens - 720p

[ computerized voice ]
hello.

My name is stephen hawking --

Physicist, cosmologist...

And something of a dreamer.

Although I cannot move...

Narrator: ...And I have to
speak through a computer...

In my mind, I am free...

...Free to explore the universe

And ask the big questions...

Such as...

Do aliens exist?

If so,
where could they be found?

What do they look like?

What are they made of?

Are they intelligent?

And if we met them,

What would it mean
for humankind?

Check it out.

Narrator:
Wherever I go in the world,

People ask me,
"do aliens exist?"

It's a good question,
because it cuts to the heart

Of how we see
our place in the universe.

Are we alone
on our small, round, blue ball?

I think probably not,
because of one fact.

The universe is big --
really big.

Our planet is just one of eight
in orbit around our sun...

...Which itself
is hardly special,

Being one of about 200 billion
stars in a vast spiral...

...Our galaxy, the milky way.

It's so big, some days
I find it hard to comprehend.

But even the milky way

Is just a tiny drop
in the cosmic ocean...

...Just one
of 100 billion galaxies

Formed into an enormous web

Stretching away
in all directions.

At this scale,

Each point of light
is an entire galaxy,

Which not only puts
our little world in perspective

But also makes it difficult
to believe we really are alone.

So to my mathematical brain,

The numbers alone make thinking
about aliens perfectly rational.

The real challenge
is to try and work out

What aliens
might actually be like,

Living on some far-off world.

Narrator: The possibilities
are infinite...

And infinitely intriguing.

Alien life could range

From simple, green slime
that doesn't do much but drip

To more advanced animals...

[ creature screeches ]

...Something
with a bit more bite.

But, of course,
that's just the start

Of what could be out here.

In such a massive universe,
it's logical to wonder

If there are
intelligent beings,

Perhaps even civilizations

Like those in science-fiction
tv shows and movies.

"star wars" and "star trek,"
two of my personal favorites,

May be closer to reality
than we think.

Similar scenarios
are at least conceivable.

But think about it more,

And even this
is limiting the options.

There could be life-forms
so strange

We wouldn't even recognize them
as life.

Perhaps there are
really exotic creatures

That live
at the center of stars...

...Or even huge communities
of microorganisms

That look like
clouds of cosmic dust.

Maybe aliens live and die
so fast

That they come and go
in the blink of an eye.

So in such a vast universe
with so many possibilities,

How do we know what to look for

Or, for that matter,
where to look for it?

The answer
is right back where we began.

The information we need
is here at home,

For the simple reason
that home harbors

The only known examples
of life.

The laws of physics appear
to be the same everywhere,

So it follows that the laws of
life should be universal, too,

Even if the detail
is different.

We can use life on earth

As a kind
of alien-hunters' handbook --

A field guide to what life
actually is and how it works,

No matter where it occurs.

Chapter 1
in our particular case

Takes us back 4.5 billion years

To when the earth
was really quite young.

Exactly what triggered life here
is still a mystery,

But there are several theories.

The most common one is that
life began purely by accident

In pools of primordial soup

Full of chemicals
called amino acids.

These molecules
would have collided at random

For millions of years

Until the perfect combination
just happened --

The ultimate lucky break
that started the chain of life.

It is extremely unlikely

That life could
spontaneously create itself.

But I don't think that's
a problem with this theory.

It's like winning a lottery.

Although
the odds are astronomical...

Most weeks
someone hits the jackpot.

But there is another intriguing
idea called "panspermia,"

Which says that life could have
originated somewhere else

And have been spread
from planet to planet...

By asteroids.

It seems possible

That lumps of rock could carry
frozen organisms inside them --

Organisms able to withstand

Extremes of temperature
and the vacuum of space.

If so,
asteroids could even now

Be transporting life
to other worlds.

Regardless
of which theory is right,

Once life begins,
the next chapter starts.

That's all about survival.

Survival links
you, me, and e.T.,

And it generates rules
all of its own.

Survival demands
a source of energy --

What we call food -- or else
it would grind to a halt.

Once nourished,
life can then copy itself

To protect against the death
of any one individual.

Ultimately,
that leads to evolution --

Evolution that would happen
even on alien worlds,

Producing, in some instances,

Animals that I think we
would recognize as being alive,

Even if they look
a bit strange.

[ creature bellowing ]

So, the next step
on our alien hunt

Is to find a place, or places,

Where organisms might find food

And replicate and evolve.

And as far as we know,
that requires one thing.

[ thunder rumbles ]

Like most people,

I find water
both beautiful and fascinating.

But it's also the key
to all known forms of life,

From bacteria to blue whales.

Narrator: Find water elsewhere
and aliens could exist nearby.

The good news is

That water is very common,
indeed...

Out in space.

Frozen water
litters the universe,

From tiny, single crystals

To icy comets
the size of mountains.

But to find liquid water,

We need somewhere
at the right temperature.

Around every star is a region

Where it's not too hot
or too cold, but just right...

Like the porridge

In the story of
goldilocks and the three bears.

Around our sun,

There are two planets that lie
in this "goldilocks" zone --

The earth and mars...

Which is why one day
I'm sure we'll pay it a visit.

[ motor whirring ]

Robots have been exploring mars
since the '70s,

But they have yet to find life.

I don't think
we should give up.

Beneath the martian surface,

Nasa's spirit rover discovered
these white salts,

Which are formed
in contact with liquid water.

Satellite images reveal
drainage patterns and erosion

Of the kinds
caused by rivers and oceans.

There may well still be moisture
under mars' surface --

Moisture that perhaps
could support life.

[ device beeps,
radio chatter ]

[ device beeps ]

I hope one day
we will find the money

To send men and women to mars.

It would capture
the public's imagination

Just as the apollo
moon missions captured mine

Back in the '60s.

[ radio chatter ]

If they found
even a few martian microbes,

In my opinion,

It would be one of the most
exciting discoveries ever made.

But even if mars is barren,

There are other places
to look for liquid water.

One of them lies a mere
30 million miles from mars...

On a small, mysterious moon

That orbits
the giant planet jupiter.

This is europa.

Europa is tiny --

Just under 2,000 miles
in diameter --

And it's very cold --

Minus 260 degrees.

The entire moon is covered

In a layer of ice
perhaps 15 miles thick.

But europa may have
a hidden heat source

Beneath the surface.

Europa orbits jupiter
once every 3.6 days,

In an egg-shaped path.

The gravitational pull
from jupiter

Changes constantly,

Stretching,
then compressing europa.

This process is like
kneading a piece of clay

To make it warm and soft,

And the heat produced
may be enough

To melt the underside
of the ice sheet...

Creating a hidden ocean
of liquid water

Protected
from the vacuum of space

By the solid ice above.

If so, there could be aliens
living here --

Creatures that have evolved

To exploit this dark
and ancient water world.

I think it's even reasonable

To guess at some
of their physical features.

[ creature chitters ]

Aliens here would probably swim

In a similar way
to our own ocean life,

Since liquid water
is the same stuff everywhere.

[ creature chitters ]

They might use chemicals
in their skin

To generate their own light,

As many deep-sea creatures do
back home.

They might even swim
in school-like colonies,

Just as aquatic animals do
on earth.

But even if advanced animals
do live inside europa,

I think they're unlikely

To be trying to make contact
with us anytime soon.

They'd exist cocooned
in an icy shell 15 miles thick,

So they'd be blissfully unaware
of the universe beyond.

To find them, we'd need to send
a mission here,

Which would be
even more risky and expensive

Than visiting mars.

I hope one day we will discover
europa's secrets.

But before then, it's worth
continuing our journey

To search for aliens
with a wider outlook.

I think we need to leave
our solar system

And voyage into the vastness
that lies beyond.

Stars surround us
in the universe,

But until recently,

No one knew how many had
planets in orbit around them,

Let alone
if any of those planets

Could support alien life.

Narrator:
Finding out is tough,

Because stars are big
and blindingly bright.

Planets are tiny and dark.

Spotting them requires
technology

On an enormous scale.

The binocular keck telescope
in hawaii,

With its twin 30-foot mirrors,

Is one of the most powerful
land-based telescopes

Ever built.

But even this vast machine
can't see distant planets.

Instead, it looks
for stars that wobble --

The telltale sign
of an unseen planet in orbit.

A hammer thrower demonstrates
the principle.

As he spins,
the hammer pulls on his body

And he wobbles
from side to side.

The same thing happens

As a planet swings
'round its star.

Planets also reveal themselves

If they pass
between their star and us.

The planet causes
regular dimming,

And from the timing,
we can even determine

If it's inside
the star's "goldilocks" zone.

The first distant planet
was discovered

In 1995.

Since then,
hundreds more have been found.

This, I think,
is a pretty exciting discovery.

We could be on the verge
of a major breakthrough...

Narrator:
...One that will both redefine

Our view
of life in the universe

And be a real triumph
for science itself.

Somewhere out there,
perhaps not so far away,

Is a rocky planet
a bit like earth --

A planet with liquid water,

Where life has begun.

Due to the power of evolution,

Aliens here
might be surprisingly familiar,

Even if, at first,
they seem anything but.

Aliens that eat, for example,
need an input orifice,

Or, as most people say,
a mouth.

Likewise, if they live
on a solid surface,

They'll probably have legs.

The detail might be different,

But legs are good things
to have on land,

Especially if the animal

Is clinging
to the side of a cliff.

[ creature bellows ]

If the planet is well-lit,
eyes are almost guaranteed.

They let a creature accurately
sense its environment.

Even the position of the eyes

Will follow the same rules
as on earth.

Prey animals tend to have eyes
on either side of their head,

Allowing them
to look out for predators.

[ creatures screeching ]

Predators, even alien ones,
need forward-facing eyes

To accurately judge distance --

An essential skill
when hunting.

[ thud ]

Alien struggles
of life and death

Are probably happening
right now,

Thanks to the universal power
of evolution.

But in my opinion,
evolution is so remarkable,

We can't really be sure
of its ultimate limits.

Life-forms on earthlike planets
or in hidden oceans

Are not the only options.

We can go even further
into the depths of the universe

In search
of other kinds of aliens --

Extraterrestrials
that are totally unlike us --

Life...But not as we know it.

I like to think of myself
as an optimist,

And so in our vast,
ancient universe,

With its countless galaxies,

Almost any life-form
that is physically possible...

Narrator: ...Is likely
to exist somewhere.

So there could be --
perhap.Shoul be --

Really bizarre aliens

That have followed a different
evolutionary path...

...Aliens that don't depend
on water,

But on other chemicals instead.

Nitrogen is one possibility.

It's a gas on earth,

But it can exist as a liquid
when it's very, very cold --

Minus 320 degrees fahrenheit.

So, is there a world
of nitrogen oceans,

Lapping, frozen shores,

Where aliens have evolved

In temperatures that would
kill a human instantly?

Life here would need chemistry
very different than our own --

A cold-weather remix of
the ingredients that make us.

Ingredient number one,
of course, is water.

The average male
holds 8 gallons.

So, let's swap water
for liquid nitrogen.

There's also
about 2 pounds of phosphorus,

Half a pound of salt,

Enough iron to make a nail,

3 pounds of lime,
15 trace elements,

Which might also work
in alien biology,

And then this...

Carbon, 45 pounds of it.

But what if carbon was switched
with something else?

Silicon, perhaps.

Silicon has
slightly different properties,

But it could do the same job.

[ wind howling ]

With the right ingredients,

Ultra-low-temperature life
might be possible.

If so, I think
energy would be scarce,

So things 'round here
would move very slowly.

[ wind howling ]

[ creature bellowing ]

Other possibilities
are even stranger.

The astronomers searching
for far-off planets

Have discovered that many
seem to be giant gas planets...

Like our own
jupiter and saturn.

Perhaps there are aliens
made of gas.

[ thunder crashing ]

Aliens living here would need
to consume something.

I imagine they could use
the power of lightning storms

That constantly rage
on planets like these.

If such extreme life-forms
are possible,

Then life
elsewhere in the universe

Could be very common, indeed.

There are certainly
many more planets

That fall outside the
"goldilocks" regions of stars

Than fall inside them.

It suddenly seems
like there could be life

Nearly everywhere you look.

But, ultimately, I think
it doesn't really matter

What aliens are made of.

To me, it's what they can do
that counts.

Are they thinking
about the cosmos, too...

...Trying to unlock its secrets
just as we are?

In short, has alien life
evolved as we have

And developed intelligence?

Narrator:
If the universe is full

Of intelligent,
spacefaring aliens,

I think at least some of them
might be interested in us...

If only as a curiosity.

Of course, many people believe
they are already here.

[ country music playing ]

Tales of alien abduction
have been common

Ever since I was
an undergraduate in the 1950s.

And I watched
all those "b" movies, too.

The story always goes
the same --

A lone individual
on a quiet road at night

Happens to take an unscheduled
detour and finds himself lost.

[ birds, crickets chirping ]

[ whirring ]

[ wind howling ]

I'm always a bit suspicious
when I hear these tales.

Look at it
from the aliens' point of view.

What's the point of crossing
vast tracts of the universe

In a high-tech ship

Just to abduct
some lone earthling?

In my opinion,
if aliens are here,

I suspect the newspapers
would be full of the story.

And if governments are involved
in their cover-up,

They're doing
a much better job at it

Than they seem to do
at anything else.

So, the lack of alien contact

Raises
a serious scientific problem.

Narrator:
Where is everybody?

We've been listening to space
for over 40 years.

And in all that time,
we've picked up nothing.

Well, except
for one mysterious occasion.

[ computers beeping, whirring ]

On August 16, 1977,
a radio telescope in ohio

Picked up a signal
that became famous.

The telescope listened to space

By scanning the skies
as the earth rotated.

And just once,

It recorded a signal
that got everyone excited --

The "wow!" signal,
as it became known.

The signal was a steady source
of radio waves,

Just the kind
an alien race might send,

Because it stands out

From the radio static
that fills the universe.

A computer recorded the signal
as six letters and numbers.

Astronomer jerry ehman
saw the data

And wrote one word
in the margin.

Ehman and others
subsequently searched

The same patch of sky
many times...

But found nothing.

The "wow!" signal had vanished.

The whole mysterious episode
reveals

That making contact with aliens
via radio

Is always
going to be difficult.

In such a vast universe,

Messages take a long time
to reach their destination.

The "wow!" signal appeared
to come from a star system

200 light years away.

So it took at least 200 years
to reach us.

If we sent a reply,

It would take another 200 years
to reach them,

By which time they might have
forgotten they sent anything

And stopped listening
for a reply.

Worse, they might well have
destroyed themselves

In the meantime.

The human race
very quickly discovered

The power of the atom bomb.

If the same holds
for intelligent aliens,

Then they might not last long.

Perhaps
they all blow themselves up

Soon after they discover
that "e" equals "m.C." squared.

If civilizations take
billions of years to evolve

Only to vanish
virtually overnight,

Then, sadly, we've next to
no chance of hearing from them.

They are simply too far away
in space and time to reach.

But there is
one last possibility --

That aliens who have avoided
destroying themselves

Are already colonizing
the universe.

[ siren wailing ]

Narrator: The human race
has only two options

When it comes to looking
for advanced aliens.

We can listen,
or we can be more active

And broadcast
our willingness to talk.

We'd have to think
very carefully

About what we might say.

I think this might be
just a little too risky.

We only have to
look at ourselves

To see how intelligent life
might develop

Into something
we wouldn't want to meet.

We humans are already capable

Of manipulating the course
of our own evolution.

Exactly the same, presumably,

Would be true
of advanced extraterrestrials.

Ultimately,
they could halt aging

And become virtually immortal.

What's more, they might have
reached that point

Millions of years ago.

It might sound unlikely, but if
you think about it logically,

Alien technology should be
as extraordinary to us

As a rocket ship to a caveman.

I imagine they might exist
in massive ships like these,

Having used up
all the resources

From the home planet below.

Such advanced aliens
would perhaps become nomads

Looking to conquer and colonize

Whatever planets
they can reach.

If so, it makes sense for them
to exploit each new planet

For materials
to build more spaceships

So they could move on.

Who knows
what the limits would be?

Perhaps their capabilities
would only be limited

By how much power
they could harness and control.

And that could be far more
than we might first imagine.

For example,
it might be possible

To collect the energy
from an entire star.

To do that, they could deploy
millions of mirrors in space,

Encircling the whole sun

And feeding the power
to one single collection point.

Such power
might make it possible

To walk
the very fabric of space

And create a portal
called a wormhole.

This portal would act
like a shortcut,

Allowing them to travel
huge distances

In the blink of an eye.

Like us, they would
probably have evolved

From a species used to
exploiting whatever it can.

So, if aliens ever visit us,

I think the outcome would be
much as when

Christopher columbus
first landed in america...

...Which didn't turn out very
well for the native americans.

So the journey that started
with the search for water

Has led us to far-off worlds

That I think
probably do exist.

In such a massive place
as the cosmos,

We only have to look
at ourselves

For proof
that extremely unlikely things

Can and do happen all the time.

Let's just hope
that if aliens do find us,

They'll come in peace.

-- Captions by vita -&www.M

Captions paid for by
discovery communications