All language subtitles for How the Universe Works - 3X06 Weapons of Mass Extinction

We live on a volatile
planet in a violent universe...

The universe constantly
wants to kill us.

...where planets collide.

The entire surface of the Earth
is liquefied

that was literally
a vision of hell.

Black holes blast out
invisible death rays.

It would be apocalyptic
beyond apocalyptic.

Asteroids strike
without warning.

It is a real possibility

that it could happen
in the next 10 minutes.

These cosmic killers
have struck time and time again,

wiping out entire species,

and pushing life on Earth
to the edge of oblivion.

It's happened before.
It's gonna happen again.

And our species could be next.

There will be disasters
in the future,

and one of them will destroy us.

not too hot, not too cold...

With water...

Oxygen....

Our peaceful, plentiful planet
nurtures and protects us...

But this lull won't last
forever.

There are dangers all around
and trouble ahead.

When we look around,

we think that the universe
is rather gentle.

We have warm breezes
and mild seasons.

Actually, the universe
is violent. It is chaotic.

The universe
is not a happy, safe place.

There are asteroid impacts,

and solar flares,
and supernova, and black holes,

and colliding galaxies,

and all these really amazingly
dangerous and violent events.

And the Earth
is in the cross hairs.

During the planet's

4 1/2-billion-year existence,

these violent phenomena

have wiped out
millions of species

in a series of catastrophic
mass extinctions.

Mass extinctions due to impacts
and other geologic

natural processes on the Earth
have actually wiped out

more species of plants
and animals on the planet

than exist today.

Mass extinctions
are what happens,

it just happens periodically,

and we living in the quiet time
between mass extinctions.

It's happened before.
It's gonna happen again.

The clock is ticking.

With every day that passes,

the next mass extinction gets
a step closer,

and with every new discovery,

the universe gets
a little bit more terrifying.

November 2012.

Astronomers identify
a new planet

100 light-years from Earth,

at least four times
more massive than Jupiter,

and it's gone rogue.

Unlike Earth and all the other
objects in our solar system,

this planet doesn't orbit
a star.

It really is lost in space.

When I was a kid
watching science-fiction movies,

every now and again
there would be a rogue planet,

just some planet wondering space
without a star.

And I thought
that was pretty silly,

but it turns out
that might actually happen.

When planets are forming,

they can interact
with each other gravitationally.

And it's entirely possible

that when
our solar system formed,

planets were kicked out
into interstellar space.

There could be as many
as 200 billion rogue planets

in our galaxy.

That's as many rogue planets
as there are stars in the sky.

And one of them could be
heading our way.

A collision with another planet
sounds farfetched.

Could it really happen?

As a matter of fact,
it already has.

4 1/2 billion years ago,

a young planet
veers into the Earth's orbit.

We have the Earth sitting here,

and another planet
about the size of Mars came in

and smacked us hard.

The two collided
over 25,000 miles an hour,

12 times faster than a bullet.

The impact destroys
the smaller planet.

The Earth survives,
but only just.

The violence of this is
hard to imagine.

Two planets coming together

smashing together
into one molten mass.

After an impact of that scale,

the entire surface of the Earth
is literally liquefied.

Imagine the floor
of an active volcano

with islands of solid rock

and lava spurting
right and left.

The entire surface of the planet
would've looked like that.

The Earth itself
for a little while

would've had
an atmosphere of molten rock.

And it was a, you know,
vision of hell.

Debris blasted out
at 20,000 miles an hour

orbits the molten Earth.

Gravity brings the debris
together.

The result -- our moon.

Our moon emerged
from the wreckage

of the most cataclysmic event
in our planet's history.

From destruction comes creation,

because without this lump
of cosmic shrapnel,

life on Earth might never have
gained a foothold.

The moon's gravity pulls
on the infant Earth's oceans,

spreading nutrients
from the land into the water.

And it slows the Earth's spin

from a 6 to a 24 hour day.

In this calm,
fertile environment,

one billion years
after the impact,

life begins.

If we hadn't had that planetary
collision a long time ago,

we wouldn't have the moon
today.

So, in fact,

this most catastrophic event
you can possibly think of

actually may have helped life
on Earth form in the first place

and helped us evolve over the
next couple of billion years.

But what was
a good thing in the past

would be a disaster
if it happened today.

Now, you don't want
a planetary collision now

because that would wipe out
the entire planet.

You can't even describe it
comparing it to nuclear weapons.

It would be billions
of nuclear weapons.

It's enough to melt

several miles thick crust
on the Earth all the way down.

It would wipe out
all life on Earth.

That would be it.

It would be like a hard restart
for the planet itself.

Could this nightmare
become a reality?

Right now even the closest rogue
planets we've discovered

are still trillions of miles
from Earth.

And our neighboring planets
have settled

into calm, stable orbits.

We're not gonna get
a planetary collision

any time soon,

but all the gravity
of the planets

play with each other
and change each other's orbits.

So clearly if you run
the clock work of time forward

billions of years,

yes, it's entirely possible

that we might have
another planetary collision.

You just don't have to worry
about it for a long, long time.

4 billion years ago,

a devastating collision
made life on Earth possible.

2 billion years later,

that life threatens
to destroy itself.

Our blue planet --

in a hostile universe,
it sustains and nurtures life.

2.4 billion years ago,

simple, single-celled organisms

drift through
the nutrient-rich oceans.

But their world
is about to be destroyed.

When you talk
about mass extinctions,

you have at least two types --

one danger coming
from outer space,

another from our own very
backyard on the planet Earth.

The Earth circles the Sun,

but this orbit is unstable.

Over hundreds
of thousands of years,

it changes,

swinging the planet
further out into space

and pivoting on its axis.

Tilted away from the Sun,
the Earth cools.

2.4 billion years ago,

something turns
this natural cooling

into a global catastrophe.

It is one of the most
dangerous things

in all the universe life.

Tiny organisms
populate the oceans.

There's no oxygen around

and that's the way
most of them like it.

But then a new kind
of bacteria evolves --

cyanobacteria.

And these guys create
a serious gas problem.

Imagine Earth
billions of years ago.

There's no oxygen.
Everybody's happy.

Then cyanobacteria start making
oxygen.

It's a toxic pollutant.

If there was a regulatory agency
at the time,

they would've been outlawed.

Eventually they polluted
the whole world.

They had really precipitated

an ecological crisis
of global proportions.

The great oxygen crisis

upsets the greenhouse effect
that keeps the planet warm.

Global temperatures plummet.

The ultimate culprit is biology.

Biology makes a mess
of the planet,

produces oxygen.

The oxygen destroys
the greenhouse effect of methane

and that freezes up the Earth.

2.4 billion years ago,
ice creeps out from the poles.

Instead of warming the planet,

sunlight bounces off the ice,

temperatures fall,

creating more ice which bounces
more sunlight back into space,

and so on and so on

until the cooling becomes
unstoppable.

The ice marches on.

Temperatures plunge.

The blue planet turns white.

It's a snowball Earth.

And incredibly,
this may've happened not once

but at least three times
over the following billion years

as the planet
lurched around the Sun.

But throughout all of this
and against all the odds,

a handful of species
clung to life,

thanks to volcanoes.

Even in an Earth that was
covered almost entirely by ice,

volcanoes would've been punching
through that.

So you certainly have
pockets of water lying about.

And life was able to carry on

and get through
these cold periods.

And the whole time,

the volcanoes
that help sustain life

have been pumping out
carbon dioxide.

As this greenhouse gas
increases,

the atmosphere warms.

Until 640 million years ago,

the last, great snowball Earth
ends.

And the survivors
emerge into a new world.

After snowball Earth goes away,
things get very interesting.

A lot of opportunities
open up for life,

water's flowing, ice is melting,

organic material built up
that hasn't been decomposing.

So you can imagine that there
will be a burst of development.

In the meantime,

cyanobacteria have been
churning out ever more oxygen.

Other organisms will either
learn to breathe it or die.

Many organisms decided

that this poison
could be useful,

it's energetic,

and that allowed them to have
an energy source

that was so powerful

that they could build
huge, complex structures --

poof, animals.

Snowball Earth
is an environmental disaster

and an evolutionary triumph.

Complex life flourishes.

But most of these creatures will
never evolve beyond this point.

Something stops them dead.

It is the most powerful weapon
in the universe,

and it strikes
in the blink of an eye.

In a violent universe,

against all the odds,
life survives.

But consider this --

at any moment, the universe
could pull the trigger

on a secret,
deep-space death ray,

obliterating all life on Earth.

And until the 1960s,
nobody even knew it existed.

1967 -
- the height of the cold war.

The United States
and Soviet union

raced to outgun each other,

stockpiling and testing
nuclear weapons.

America was worried
that the Soviet union

would be able to test
nuclear weapons in space.

So what America did is launch
the series of satellites

to go out into space
and look for the tell-tale flash

of gamma rays
from nuclear tests.

On July 2, 1967,

the satellites detect
a burst of gamma rays,

the most energetic
and destructive form

of electromagnetic radiation.

Immediately there was panic
in the Pentagon.

Perhaps the Russians are testing

super-gigantic hydrogen bombs
in outer space.

And we're just caught
flat-footed.

But it's not bombs.

It's something far deadlier.

And then the realization
sunk in.

"Oh, my god.

"These flashes are coming from
outside the milky way galaxy.

They must be
billions of light-years away."

A new source of energy,

second only to the big bang
itself had been discovered.

When gamma ray at first
were first discovered,

people assumed that
they must be fairly close by.

"Of course
they have to be close by.

They're the brightest thing
that we see in the sky."

And now we know
that gamma ray burst,

not only are they not nearby,

they're not in our galaxy,
they're not in nearby galaxies,

but they're close to the edge
of the universe.

They're as far away as
anything else that we observe,

and that's
completely ridiculous.

Over distance,
light gets dimmer.

The further light has to travel,
the dimmer the light should be.

If light from a distant galaxy
comes to Earth

and it has gamma-ray energies,

then that explosion must've been
incredibly powerful,

because it turns out that
as light travels through space,

the wave length of the light
gets stretched out.

And this stretching caused
the light to lose energy.

And since the light rays have
traveled a very great distance

through the cosmos to reach us,

and they're still gamma rays,

they must've started out
with a great deal of energy.

And the amount of energies
are unbelievable.

You're talking about the entire
energy budget of the Sun

over its whole lifetime

emitted over the course
of just a few seconds.

These are amazingly violent,
amazingly powerful events.

In June 2008.

NASA launches
the Fermi space telescope.

Its mission --

discover the source
of these huge blasts.

What Fermi does

is open our eyes
to the universe that's there

but gives us
such a different view

that we really get a deeper
and greater understanding

of what's going on.

If you had gamma-ray eyes,

the milky way would be
blazingly bright

across the center of the sky.

Your vision would be dominated

by these very dense,
pulsing stars

and super-massive black holes.

And it's black holes

that may solve the mystery
of gamma-ray bursts.

When a truly gigantic star dies,

one at least 25 times
more massive than our own sun,

it collapses to form
a black hole.

Scientists believe black holes

are one of the few things
in the universe

large enough and powerful enough
to generate gamma-ray bursts.

Gamma-ray bursts are
the birth cries of black holes.

When a massive star explodes
and becomes a supernova,

the core collapses
and forms a black hole.

Material falls around it,
swirls into a huge disk,

it gets incredibly hot.

As it's falling
into the black hole

it forms a tremendous
magnetic field, as well.

The remains of the star

spiral towards the black hole.

Enormous electromagnetic forces

fling some of this matter
outwards.

Hurtling up and down

the black hole's
huge magnetic fields,

the matter collides with debris
from the initial explosion,

accelerating
to close to the speed of light,

heating to millions of degrees.

These high-speed collisions

unleash unimaginable amounts
of energy.

This is the gamma-ray burst.

Gamma-ray bursts
are fascinating.

You can study them
throughout the universe

because they're so bright.

But if you move them in
really close to the Earth,

let's say within
6,000 light-years of the Earth,

they become
extremely destructive.

The beams are so huge
that if a gamma-ray burst

occurs, say,
100 light-years from us,

by the time it reaches
the Earth, the beam will be

wide enough to engulf
our entire solar system.

Basically, if you were standing
on the Earth and you looked up,

you would see a flash of light,

and before you could even say,
"what's that?"

You'd be gone.

The amount of energy in the beam
that travels across space

is so intense it would basically
light the Earth on fire

from that distance.

It would strip off
the Earth's atmosphere,

it would boil the oceans,
it would melt the rock.

It would be apocalyptic
beyond apocalyptic.

This is the worst-case scenario.

But what if a gamma-ray burst
hit the Earth from further out?

Would we survive?

People ask what would happen
if there was a gamma-ray burst

within 6,000 light-years
of the Earth.

It's actually
not the right question.

There have been gamma-ray bursts
that close to the Earth,

and there probably have been
extinctions of life on Earth

due to gamma-ray bursts.

200 million years
after snowball Earth,

the oceans are teeming
with complex life.

But 440 million years ago,

85% of all those creatures died.

And the killer may have been

a single devastating
gamma-ray burst.

The blast penetrates
the oceans' upper layers,

killing the creatures
that live near the surface.

Creatures living further down
survive the initial onslaught,

but not for long...

Because the blast also damages
the Earth's ozone layer,

exposing the planet to the Sun's
deadly uv radiation,

triggering acid rain

and lowering
global temperatures.

Over half a million years,

the creatures that survived
the gamma-ray burst

get taken out
by its after effects.

If a gamma-ray burst
has wiped out life in the past,

it could happen in the future.

And astronomers
think the next burst

could come from a dangerously
unstable star, wr 104.

Wr 104 is the nightmare.

We now have
a potential candidate

for what may become a gamma-ray
burster with our name on it.

We are literally staring
down the gun barrel of wr 104.

It's not one

but two massive stars
orbiting each other.

The stars will die
in a massive explosion,

spawning a black hole,

and blasting out gamma rays.

The object is
about 8,000 light-years away,

so we are within the kill radius
of this object.

So you could be
doing your laundry tomorrow,

look up in the sky,
and all of a sudden,

there's this burst of radiation
raining down from the heavens.

The radiation rips off
the Earth's ozone layer,

creating a toxic smog

and exposing us
to the Sun's deadly rays.

Life as we know it
could cease to exist.

Plants would be scorched,

animals,
which depend upon plant life,

will then begin to die.

Human civilization would
have to go underground.

It may sound like the death star

destroying the Earth
in "star wars,"

but the difference is the death
star isn't gonna happen,

a gamma-ray burst might.

Our extinction
could happen at any time.

And the fatal blow
doesn't have to come from space.

It could come
from the very thing

that makes life possible -
- the Earth itself.

Our planet conceals
a weapon of mass extinction,

primed to detonate
at any moment,

hidden deep beneath our feet.

Unleashed,
the heat inside our planet

could wipe out everything
in its path on a massive scale.

200 million years
after a gamma-ray burst

may have devastated life
in the oceans,

the survivors have colonized
the land.

Among them, a motley crew
of monster reptiles -

- scutosaurus and gorgonopsians.

They're successful, strong,
and doomed.

Around about
250 million years ago marks

the biggest mass extinction
that the Earth has ever seen,

the end-permian extinction.

Just over 90% of marine fauna

and around about 70%
of land fauna

disappeared from the planet.

The killer is
a volcanic eruption --

the biggest
and most catastrophic

the world has ever seen.

250 million years ago,

in what is now Siberia,

the Earth's crust ruptures,

pushed beyond breaking point

by a vast plume of hot magma

surging up
from deep inside the planet.

The Earth itself can
internally generate

some very devastating events,
millions-of-years-long events

in the form of
major volcanic eruptions

at the continent-scale level.

These are
basaltic-volcanism events

that flood entire portions
of the planet with basalt lava.

Lava spews
for two million years.

There's enough lava to cover
the entire United States

beneath a thousand feet.

And the death toll
extends around the Earth...

...and deep into the oceans.

The question is why.

The answer lies with the most
volcanic country on Earth --

Iceland - with a similar, smaller
eruption just 230 years ago.

June 1783.

A terrible chain of events
unfold

that will devastate Iceland

and kill up to a million people
around the world.

Near the village of laki,

a 17-mile-long tear
opens up in the Earth's crust.

These holes and cracks
in the ground that you can see,

they would've had jets of magma,

jets of lava
flying up into the sky.

To give you an idea of scale,

the overall the amount of
material that came out of laki

is about 3 1/2 cubic miles
of volcanic material,

and that's a lot material.

And it's not just the size of
laki that makes it so special,

it's actually what's inside this
and what came out of this

that's the dangerous thing.

Because it had
lots of sulfur gases

associated with the eruption

and also lots of fluorine,
quite poisonous gases.

Sulfur dioxide spreads
out around the atmosphere.

Its droplets form a giant mirror

reflecting the Sun's warmth
away from the Earth.

It's clear that even

a relatively small eruption
like laki

can cause big, dramatic effects
in terms of the climate.

In the northern U.S.,

there was one of the coldest
winters ever recorded.

In fact, the Mississippi is
recorded to have frozen.

It's been implicated in causing
the big famine in Japan.

So, the effects,
potentially, for volcanoes

that spew these horrible gases

into the atmosphere can be
catastrophic on a global scale.

Now picture
the siberian eruptions

250 million years ago.

They're 200,000 times larger
than laki

and last a million times longer.

They release massive quantities
of gas

triggering
extreme climate change --

first cooling,
then heating the atmosphere.

70 % of all
land-based creatures die,

including the mighty
gorgonopsians and scutosaurus.

But worse is to come.

As the oceans warm,
they lose oxygen and stagnate.

Toxic algae takes over,

poisoning the oceans
with hydrogen sulfide,

killing 96% of marine life,

and leaving
purple sulfur bacteria

to overrun the oceans,

turning the water pink.

This is the closest
the Earth has ever come

to total extinction.

But over 200 million years,
the survivors adapt and evolve.

A new group of animals emerge.

They are the largest,
most successful creatures

the Earth has ever seen -
- the dinosaurs.

But they, too, will face
annihilation.

Cosmic killers
prowl the universe

threatening to wipe out
life on Earth.

They've struck before,

pushing life
to the edge of extinction.

They will strike again,

and it could happen before
you've finished

watching this show.

February 15, 2013.

9:42 A.M.

It's another cold winter's day

in the siberian city
of chelyabinsk

when literally,
out of the blue...

A 14,000-ton, 65-foot meteor

tears through the atmosphere
at 42,000 miles an hour.

It explodes in the air
18 miles up,

unleashing
a powerful blast wave,

shattering windows,

damaging 7,000 buildings,

and injuring 1,500 people.

Now imagine
what would've happened

if the asteroid had hit
the Earth in one piece.

And we saw what happened
over Russia,

over in chelyabinsk,

with an object
that could have hit the Earth --

could've hit the Earth
with a force

of perhaps 20 Hiroshima bombs.

If you watch those videos
of that meteor in Russia

with the incredible Sonic boom,

you could see
how even a small object --

relatively small
in a cosmic sense --

could produce a dramatic event
for humans.

The way it works is

small objects are hitting
the Earth every day,

large objects, every week,

larger objects still,
every year.

And an object the size
of the chelyabinsk meteor

strikes, on average,
once every century.

So when
the next big one strikes --

not if...

...what will happen?

The clues lie in the past

in the extinction
of the dinosaurs.

About 65 million years ago,

there was a perfect morning
on Earth.

I would've loved
to have been there

to see the giant dinosaurs,
you know,

the pterodactyls flying
through the air, all of that.

And then something changed,

and the Earth
would never be the same.

If you would've looked
into the sky,

you would've seen
a relatively dim light at first

coming towards you,
getting brighter and brighter,

and hotter and hotter.

It's a six-mile-wide rock

the size of mount Everest

racing towards the Earth
at 25,000 miles an hour.

The first wave of destruction

would've started
before this object even hit.

There would've been
shock waves, heat, and winds

going across the entire planet.

Everywhere that was
under the path of this asteroid

would've been seared,
set on fire.

The oceans would've been boiling
underneath it.

The asteroid smashes
into the ocean

off of what is now
Mexico's Yucatan peninsula.

It strikes with a force
two million times greater

than the biggest
nuclear bomb ever detonated,

and blasts out a crater
200 miles across.

A super-heated shock wave roars
out at twice the speed of sound.

500 billion tons of red-hot rock
soar to the edge of space.

Two hours after impact,

a 300-foot Tsunami
smashes into the coast

of what is now the U.S.A.

Reaching as far
as North Carolina.

Over the next few hours
and days,

the debris rains down,
setting the planet ablaze.

In the following weeks
and months,

smoke from the fires

adds to the dust
blasted into the atmosphere.

There was
so much pulverized rock,

all of the burning materials
up into the atmosphere,

you wouldn't have been able
to see the surface.

And on the surface, you wouldn't
have been able to see the Sun,

and it was like that
for a long time.

This ancient apocalypse

is a disaster
for the dinosaurs...

...but without it,
we wouldn't be here.

Back then, during the time
of the dinosaurs,

our ancestors were
probably little, furry mammals

that were an evening snack
for a dinosaur.

When the dinosaurs
got wiped out,

these small, little,
furry mammals

began to expand in size

to take over the niche
left over by the dinosaurs.

So, one life-form replaces
another life-form,

in this continual process
called survival of the fittest.

We are here
because our ancestors

survived the extinction event,

and, in fact,
flourished because of it.

From our point of view,

that extinction event
was a good thing,

but we're here
for a brief moment.

And there will be disasters
in the future,

and one of them will destroy us.

There is a 1 in 5,000 chance

that an asteroid, the same size
as the dinosaur killer,

will strike
within the next 100 years,

and it could happen at any time.

It is a real possibility

that it could happen
in the next 10 minutes,

but is a tiny possibility.

So, I always say, "you don't
need to prepare very much

"for winning the lottery,
you know.

"You may have a similar chance
to getting taken out

by an asteroid
in the next 15 minutes."

April 2014.

Scientists make
a shocking announcement --

since the year 2000,

26 asteroids have exploded
in the Earth's atmosphere,

each one with the force
of a nuclear blast,

with some up to 40 times
more powerful

than the Hiroshima bomb.

And we didn't spot a single one
of them before they struck.

Even if we had the technology

to detect an asteroid
before it hit us,

could we destroy it in time?

The Hollywood favorite,
of course, is to go out there

and nuke it,
blow it to smithereens, right?

That could actually work
in the case of some particular,

you know, last-ditch effort

for asteroids
of just the right size.

But a nuclear bomb

could just make a bad situation
worse.

Transforming an asteroid

into large radioactive chunks

that rain down
all over the planet.

But there are also techniques,

like shining a laser
on the asteroid or sunlight,

which would create
an artificial cometary jet,

if you will, would vaporize
some of the water

and the minerals
on the surface of that asteroid

to gently push it off
to the side.

Another fantastic technique,
a very robust one,

is something we call
the gravity tractor.

You just park a spacecraft,

the mass
of a communication satellite,

next to that small asteroid

and use the thrusters
on the spacecraft

to keep it hovering just
off the surface of the asteroid,

and that uses then gravity
between the two as a tow line

to move the asteroid
ever so gently off course.

Right now

these technologies
are still on the drawing board.

If they do become a reality,

we'd still need months or years
to prepare.

Rogue planets, ice ages,

gamma-ray bursts,

volcanic eruptions,

and asteroid strikes.

We've survived the worst
the universe can throw at us,

but our species will still face
extinction.

It's as inevitable
as the Sun rising.

In a cosmic battle
to the death,

we are the survivors,

but eventually
the universe will win

and we will face extinction...

Threatened by the very thing
that gives us life --

our creator, the Sun.

We orbit
a giant nuclear bomb, the Sun,

but, you know,
it's not going to explode.

It's too small to explode,

but what happens with the Sun
is that every day,

it's a little bigger
than it was the day before.

Since the Sun's birth,

hydrogen has been fusing
into helium in the Sun's core.

As the helium accumulates,
the core gets denser.

With 150 million tons of helium

squeezing into the core
every second,

the gas compresses and heats up.

Right now the temperature
inside the Sun's core

is 27 million degrees,

and its getting hotter
all the time.

What happens
when you heat up a gas?

It expands, and so that's
what the Sun is going to do.

As the Sun swells,
it will appear brighter.

In 2 billion years,

the Sun will be
about 15% brighter

and that will lead

if the Earth remains
in its present orbit

inevitably
to a runaway greenhouse effect.

The oceans will evaporate,

and the surface temperature
of the Earth

could easily be a 1,000 degrees.

So, if we don't do anything,

in 2 billion years,
we'll be toast.

If we're still here
on Earth, we'll perish.

Other tougher species may find
a way to adapt and survive,

but they'll be living
on borrowed time.

It's gonna fill up the sky.

From horizon to horizon,

the sky will literally be
on fire.

5 billion years from now

the Sun runs out of hydrogen

and enters the final
apocalyptic stage of its life,

bloating to 100 times
its current size.

Our life-giving sun
is now an angry, red giant.

The red giant stars are so big

they will actually eat up
their own planets.

We know of the examples
of red giants that go

all the way out to where
the orbit of Jupiter is

in our solar system.

The sun will not get
quite that big,

but it'll probably
get about out to Mars.

And eventually, in fact,
the Sun will be so large

that the Earth will be located
inside of the Sun,

which certainly won't be
a very pleasant place to be.

The red giant's bloated body

absorbs the Earth,
incinerating our planet

until its nothing more than gas
and dust inside a dying star.

The death of the Sun

is the ultimate
mass-extinction event.

There's 100% chance
it will happen.

A 100% chance
it will destroy our planet

and any life left on it.

But life on Earth may not be

the only life
in the solar system.

As the Sun brightens,

you can imagine a wave
of habitability going out.

So right now it's on Earth,
it'll go to Mars,

and it'll go to Jupiter,
and its moons.

Scientists think
Jupiter's moon europa

may already harbor alien life

in a deep, liquid ocean
beneath its frozen crust.

But out at Jupiter,
it'll be much warmer

but not so warm that
it would destroy everything.

So even when the Earth is gone,
if there's life on europa,

it may be able to endure that.

But will our species go on?

Can we survive the loss
of our home planet?

The universe is
like an ecosystem --

living things
are gonna survive

based on the law
of survival of the fittest.

What decides if you're fit
in this universe

is if you're able
to leave your planet

and go out and populate
other planets.

So the only species that
are gonna live on forever

are the ones
that leave their planet.

We can't control the universe,

but we may be able
to control our fate.

Inevitably, in the long term,

the Earth is gonna become
uninhabitable.

It's just the way
the universe works.

It wasn't made for us,
it doesn't care that we exist,

and it won't care
when we go away.

The only people
who care about that are us,

and we might be able
to do something about it.

In that sense,
we have a fighting chance.

Our intelligence
is our greatest asset.

It's the end result
of four billion years

of extinction and evolution.

And it may give us a chance
to do something

that no other species
has ever done before --

break the cycle
of creation and destruction

and live on.

Everything that you and I are

is a consequence
of the way the universe works.

The universe is violent,
the universe is dynamic,

it's constantly
pushing us to change.

And here we are,

these incredibly evolved,
interesting creatures.

We're a direct consequence
of the violence,

which, in turn,
was our creation.