All language subtitles for Cosmos.A.Spacetime.Odyssey.S01E09.720p.5.1Ch.BluRay.ReEnc-DeeJayAhmed-eng

Yes, this is home.

This is Earth.

Having trouble finding
a familiar continent?

The past is another planet.

Actually, many.

I'm standing on the great
expanse of time that has elapsed

since the Big Bang.
In order to think about it,

we've compressed it all
into a single year.

It's the early morning
of December 23

on this Cosmic Calendar of ours,

or about 350 million years ago,

when our world was
a mere four billion years old.

Earth looks so different.

You might not
even know the place.

The stars wouldn't help you.

Even the constellations would
have been different back then.

The dinosaurs were still

more than 100 million years
in the future.

There were no birds,
no flowers.

And the air was different, too.

The atmosphere had more oxygen
than at any other time

in Earth's history,
before or since.

This allowed insects to grow
much larger than they do today.

How?

Insects don't have lungs.

Life-giving oxygen is taken
in through openings

in the outside of their bodies

and transported
through a network of tubes.

If an insect were too large,

the outer reaches of these tubes
would absorb all the oxygen

before it could ever get
to its internal organs.

But during
the Carboniferous Period,

the atmosphere had almost twice
the oxygen as today.

Insects could then grow
much bigger

and still get enough oxygen
in their bodies.

That's why the dragonflies here
are as big as eagles

and the millipedes
the size of alligators.

So why was there
so much oxygen back then?

It was produced
by a new kind of life.

Sync and corrections by n17t01
www.addic7ed.com

What kind of
life could've changed

the Earth's atmosphere
so dramatically?

Plants that could reach
for the sky--

trees.

In their competition
for sunlight,

trees evolved a way
to defy gravity.

Before trees,
the tallest vegetation was

only about waist-high.

And then something wonderful
happened.

A plant molecule evolved that
was both strong and flexible,

a material that could support
a lot of weight,

yet bend in the wind
without breaking.

Lignin made trees possible.

Now life could build upward.

And this opened
a whole new territory,

a three-dimensional matrix

for communities
far above the ground.

Earth became
the Planet of the Trees.

But lignin had a downside:

it was hard to swallow.

When nature's demolition crew,
the fungi and bacteria,

tried to eat anything
with lignin in it,

they got a really bad case
of indigestion.

And termites wouldn't evolve

for at least
another 100 million years.

What to do
with all those dead trees?

It took the fungi and bacteria
millions of years

to evolve the biochemical means
to consume them.

Meanwhile, the trees just kept
springing up,

dying, falling over

and getting buried by the mud
that built up over eons.

Eventually, there were
hundreds of billions of trees

entombed in the Earth,

buried forests
all over the Earth.

What possible harm
could come from that?

This cliff in Nova Scotia
is another kind of calendar.

It tells the story
of that other world

that once flourished right here.

And this is the death mask

of that 300 million-year-old
tree.

It was cast by minerals
that replaced the original wood

cell by cell--
in other words, a fossil.

The tree surrendered
its organic molecules

to the environment long ago,

its carbon and water.
Only its shape remains.

When this tree was alive,
it took in carbon dioxide

and water and used sunlight

to turn them
into energy-rich organic matter.

The tree gave off oxygen
as a waste product.

That's what trees
and other plants still do.

When plants die, they decay,

and this reverses
the transaction.

Their organic matter combines
with oxygen

and decomposes,

putting carbon dioxide
back into the air.

This balances the books

for the chemistry
of Earth's atmosphere.

But if the trees are buried
before they can decay,

two things happen...
they take the carbon

and stored solar energy
with them

and leave the oxygen behind

to build up in the atmosphere.

That's what happened
around 300 million years ago.

There was an oxygen surplus.

That's how the bugs got so big.

And what became
of all that buried carbon?

It lay there for eons
before dealing life on Earth

its most devastating blow
of all time.

There are places on this planet
where you can walk through time

and read the history
written in the rocks.

This beach in Nova Scotia
is one of them.

Every layer is a page.

Each one tells the story
of a flood,

one after another,
over millions of years.

The layer cake of flood
deposits was slowly buried

and turned into rock
by heat and pressure.

The same forces
that built mountains

then tilted and uplifted them,

along with the entombed
fossil forest.

The newer layers were always

deposited on top
of the older ones.

All the pages are
in the correct order,

bearing witness
to what happened here

over millions of years.

Back that way

lies the more distant past.

And with every step I take,

I move about 1,000 years
closer to the present

and away from the world
of 300 million years ago.

50 million years later
lies that way.

This was the beginning of
the end of the Permian world,

an event of unequalled carnage.

The Permian
is the darkest corridor

in this memorial to the broken
branches on the Tree of Life--

the Halls of Extinction.

Death has never come so close

to reigning supreme
on this world

in the quarter billion years
since.

The eruptions,
in what is now Siberia,

lasted for hundreds
of thousands of years.

The lava flooded and buried more
than a million square miles.

This event dwarfs
any volcanic eruption

in historical times.

_

Huge quantities
of carbon dioxide came pouring

out of the volcanic fissures.

This greenhouse gas
warmed the climate.

And this is where
the long-buried forests

of the earlier Carboniferous
Period reenter the story.

During the intervening
50 million years,

those trees had turned
into immense deposits of coal,

and as it happened,

one of the world's largest

accumulations of coal

was buried right there
in Siberia.

The heat from the lava
baked the coal,

driving methane and sulfur-rich
gases out of the ground.

They were laden

with toxic
and radioactive ash particles--

coal smoke.

This witch's brew
polluted the atmosphere

and radically destabilized
Earth's climate.

A sulfuric acid haze
blocked incoming sunlight

and darkened the planet.

Global temperatures plummeted
to subfreezing.

During lulls in the eruptions,

the acid haze fell back
to the surface.

But the carbon dioxide remained

and built up in the atmosphere
to cause global warming.

Years of frigid cold

alternating with millennia
of stifling heat

battered a dwindling population
of plants and animals.

They had no chance

to adapt to the drastic swings
in climate.

As the global warming

continued, the surface
and the bottom waters

slowly mixed,
raising the temperature

of the once-frigid depths
of the sea floor.

Methane-rich ices

that had been frozen in
the sediments began to melt.

Newly liberated methane gas
made its way to the surface

and into the atmosphere.

Methane traps heat
far more efficiently

than carbon dioxide,
so the climate

got even hotter.

And the methane also destroyed

the ozone layer
in the stratosphere.

The natural sunscreen
that protects life

from deadly ultraviolet rays
was eaten away.

The circulatory system
of the world ocean shut down.

These stagnant waters
became oxygen-starved,

killing almost all
the fish in the sea.

But one kind of life flourished
in this brutal environment...

bacteria that produced
deadly hydrogen sulfide gas

as a waste product.

That was the last straw.

The poison gas killed almost
all the remaining plants

and animals on the land.

This was the Great Dying.

The closest life on Earth
has ever come to annihilation.

Nine in ten
of all species perished.

It took a long time
for life to bounce back.

For a few million years,
Earth could have been called

the Planet of the Dead.

We are descended
from one of the few species

that managed to squeak by.

You are human and alive
at this very moment

because they managed
to endure, conveying

their DNA through one of
the most treacherous periods

in the history of life.

This mountain
was made entirely by life.

The life that flourished
back in the glory days

of the Permian,
before all hell broke loose.

This is part
of the 400 mile-long

Guadalupe Mountain chain
that runs through

Texas and New Mexico.

It's the world's
largest fossil reef.

All this was once
a great inland sea.

The reef flourished and grew
for millions of years,

and was home to multitudes
of sponges, green algae,

and animals too small to see.

When these creatures died,

they sank to the bottom
and were buried in the silt.

Over millions of years,

their remains were converted
into oil and gas.

Eventually, the basin

silted in and the reef died.

This marine ghost town
was then buried

a mile beneath the surface.

Later, tectonic forces
lifted the skeletal reef

high above sea level,
where it was eroded and sculpted

over eons by wind and rain.

Just imagine what
this place looked like

275 million years ago,

when it was a vibrant,
tropical inland sea,

dotted with islands

and brimming with life.

Until about
220 million years ago,

New England and North Africa
were next-door neighbors.

There was no such thing
as the Atlantic Ocean.

Those thin blue fingers
at the center-- they were lakes.

They were the first outward
signs that the supercontinent

was splitting apart and that

life on Earth was due
for another big shake-up.

A million years later,
the lakes became a long bay,

which would grow
into the Atlantic Ocean.

These profound changes
at the surface

were merely symptoms of a drama
that was unfolding far beneath,

in the depths of the Earth.

By the time we got here,
the telltale traces

of global upheaval were buried

at the bottom
of the deep blue sea.

We were completely cut off
from the great story

of Earth's violent past--

a species of amnesiacs
trying to find out

who we were and what happened

before we awakened.

In 1570, Abraham Ortelius
created the first

modern world atlas,
reflecting on the discoveries

of the previous 80 years--

the Golden Age of Exploration.

Before the ink was dry,

Ortelius stepped back
from his masterpiece

and became the first of many
to notice the striking

puzzle-piece fit
between the continents

on either side of the Atlantic.

He later wrote that the
Americas were torn away

from Europe and Africa
by earthquakes and floods.

But Ortelius's observation

remained nothing more
than a hunch

for the next
couple of centuries...

until an early 20th century

German astronomer
and meteorologist

amassed the evidence

to build the
scientific case for it.

Alfred Wegener had been drafted
during the First World War,

but was wounded soon after.

As he recovered
in a field hospital,

he scoured scientific
literature

for clues to the Earth's past.

Years before,

Wegener had happened upon
an intriguing paper

in the stacks
of his university library.

It puzzled Wegener

that fossils of the same
species of a now-extinct fern

were reported to be found
on both sides of the Atlantic.

Even more curious were
the discoveries of fossils

of the same dinosaurs
on both continents.

In the early 20th century,

geologists explained
how life crossed the oceans

by imagining that land bridges
had once existed between them.

It was thought that these land
bridges gradually disintegrated

and vanished
beneath the waves long ago.

But there was one piece of
evidence that convinced Wegener

that the prevailing
scientific view must be wrong...

the Earth itself.

Why would a mountain range
cross the oceanic divide

to continue
on another continent?

And why would you find
the same unique pattern

in the layers of rocks in both
Brazil and South Africa?

And another thing...

under what circumstances could
tropical plants have flourished

in the frozen wastes
of the Arctic?

Wegener concluded
that there was only

one logical solution
to this puzzle...

There had once been a single
supercontinent on Earth.

He named it Pangaea.

So Wegener becomes the toast
of the scientific world, right?

Not exactly.

Most geologists ridiculed
Wegener's hypothesis

of continental drift.

They preferred their
imaginary natural land bridges

to explain away
Wegener's evidence.

How, they asked, could
a continent plow through

the solid rock
of the ocean floor?

Wegener had no
convincing answer.

He became the laughingstock
of the field;

a pariah at scientific
conferences.

Despite this, Wegener continued
to fight for his ideas,

conducting daring research
expeditions to gather evidence.

On one of these, he learned
that colleagues were

trapped on an ice cap
without food.

On his way back
from the mission,

he became lost in a blizzard.

A day or two after
his 50th birthday,

he disappeared,

never knowing that, in time,

he would be vindicated
and come to be viewed

as one of the greatest
geologists in history.

Scientists are human.

We have our blind spots
and prejudices.

Science is a mechanism

designed to ferret them out.

Problem is, we aren't
always faithful

to the core values of science.

Few people knew this better
than Marie Tharp.

It's 1952, and Marie is
patiently enduring the slights

of her fellow members
of the geology department.

Her degrees in geology
and mathematics

count for little with them.

Bruce Heezen, a graduate
student from Iowa,

has just returned
from a lengthy expedition

to map the ocean floor
using sonar.

Will you do something
with these?

Bruce, look.

It's-- it's all come together.

There's this giant rift valley

that runs through
the bottom of the Atlantic.

Aw, geez, Marie, come on.

This is just more girl talk.

You're not in enough trouble
with everyone here already?

This sounds too much
like continental drift.

You want to end up
like Wegener?

But Marie
would not be dissuaded.

Years later, when Marie and
Bruce placed a map of oceanic

earthquake epicenters
on a light table

over her seafloor map,

the earthquakes
fell right along

the rift valley.

This was the smoking gun

for Wegener's
moving continents.

Heezen now knew

that Marie had been
right all along.

Together, they created the
first true map of the Earth,

including the ocean floor.

We were at last ready to read

the autobiography of the Earth.

Let's take
the Ship of the Imagination...

to a part of the world
that has been off-limits

to all but a few of us.

Two-thirds of the Earth

lies beneath more than
1,000 feet of water.

It's a vast and largely
unexplored frontier.

Everybody knows the Alps
and the Rockies,

but some of the world's
most amazing mountain ranges

are hidden from view.

Below 1,000 meters,
we enter a world

where there is no sunlight.

Hidden in the darkness,
a world of wonders.

This is the longest submarine
mountain range in the world,

the Atlantic Mid-Ocean Ridge.

It wraps around our globe
like the seam on a baseball.

The past is another planet,

but most of us
don't really know this one.

We don't see the mountains
for the water.

This is the world that Marie
Tharp was the first to imagine.

The highest peaks of the ridge

rise over four kilometers above

the ocean floor.

There are sprawling mountain
ranges and canyons, too.

We've now entered
the Marianas Trench,

the deepest canyon on Earth,

more than ten kilometers deep.

It formed when tectonic forces
pushed the seabed

under the adjoining
continental plate.

More people have walked
on the Moon

than have ever been down here.

The pressure here is a crushing
eight tons per square inch.

Being this deep in the ocean

is like having 50 jumbo jets
stacked on top of you.

Yet even here,
life has taken hold.

The fact that sunlight
can't penetrate the deep ocean

doesn't mean
there isn't light down here.

Many underwater species glow
in the dark,

through a process
called bioluminescence.

Our long history
as land mammals,

denizens of the sunlit world,
hasn't prepared us

for the amazing variety of life
that evolution

has crafted in the deep oceans.

Since there's no sunlight
down here,

there's no photosynthesis.

That means there are
no plants to feed on,

and yet, even here, in a world
of permanent midnight,

there's a thriving food chain.

It begins

with a process
called chemosynthesis.

These microscopic creatures
have learned to eat

what's pouring out
of that vent...

a noxious compound
called hydrogen sulfide.

That thick

black smoke provides
the chemical energy

that makes life possible here.

Tiny crustaceans
eat the bacteria,

and the larger animals
eat the crustaceans.

One day, on some future Earth,

these mountains could very well

end up above the water.

Tectonic forces continue
to shape our planet.

The future
is also another planet.

It was a volcano like this one

that created the Hawaiian
islands millions of years ago.

We live on the crust
of a seething cauldron.

At the center of our planet,
there's an iron core.

It's nested inside
of a larger, liquid iron shell.

Wrapped over this is the part
called the mantle.

It's rocky but hot and viscous.

Like a pot of soup cooking
on a stove, the mantle

is churning.

What keeps it moving?

Two things... the heat left over
from Earth's formation,

and the decay of radioactive
elements in the core.

And this outer layer--
the crust,

where you and me
and everyone we know lives--

is only as thick
as the skin on an apple.

The mantle

drags the solid overlying
crust along with it.

The crust resists
because it's cool and rigid.

From time to time,
it reaches the breaking point.

When that happens,
the Earth quakes.

It's not because
somebody misbehaved

and is being punished.

It's due to random forces

that are governed
by the laws of nature.

Our sense of the stability
of the Earth is an illusion

due to the shortness
of our lives.

If we could watch our planet
on its own timescale,

in which big changes take
millions of years to play out,

we would see it as the dynamic
organism it really is.

This is the world
of the late Triassic period

about 200 million years ago.

That little guy?

It's one of
our distant ancestors.

He lived in Newark, New Jersey.

Wherever you walk on Earth...

lost worlds lie buried
beneath your feet.

50 or 100 million years ago,

even the most
seemingly ordinary places

have been the scene
of epic change.

These Palisades are a monument

to the breakup of
the supercontinent Pangaea.

The sequence
of volcanic eruptions

that made these cliffs also led
to the next mass extinction--

the one that ended
the Triassic world.

But a catastrophic

extinction event for one species

is a golden opportunity
for another.

The Triassic extinctions
offered one group

that had been around
for a while

the chance
to take center stage.

The dinosaurs
had a good, long run

for 170 million years.

Back then, India was an island.

It crept northward at the pace
of a few inches per year

on its slow but inexorable
rendezvous with Asia.

Then, once again,

the molten rock beneath
Earth's surface

burst forth and flooded
a huge area of western India.

The knockout punch

literally came out of the blue.

Few animals
larger than a hundred pounds

survived the catastrophes
of the late Cretaceous.

The dust cloud brought night and
cold to the surface for months.

The dinosaurs froze
and starved to death.

But there were small creatures

who took shelter in the Earth.

And when they emerged...

they found that
the monsters who had hunted

and terrorized them were gone.

The Earth was becoming
the Planet of the Mammals.

And the Earth continued
its ceaseless changing.

This was once a desert
where nothing could grow.

It was a million square miles
of sand and salt,

far more hostile than
any environment on Earth today.

Daytime temperatures were
hot enough to bake bread.

And it was more than a mile
below sea level,

so the atmospheric pressure

was about 50% higher
than what we're used to.

It would be hard to think

of a more unpromising
environment on this planet.

Yet this was the basin
of the Mediterranean

five and a half
million years ago,

before it became a sea.

The Earth never
stops moving for long.

The natural dam
at the western end

of the deep basin

gave way,
probably due to earthquakes.

And the deluge began.

The torrential waters rushed in
at a rate 40,000 times greater

than Niagara Falls,
turning a vast desert

into the Mediterranean Sea...

in less than a year.

There were as yet no humans

to witness this enormous flood,

nor to admire
the beauty it created.

Meanwhile, half a world away,

a broad channel separated
North and South America...

allowing ocean currents to flow

from the Atlantic
into the Pacific Ocean.

Tectonic forces
gradually brought

these two continents together,
closing the channel

and creating
the Isthmus of Panama.

This reorganized the worldwide
pattern of ocean currents,

which, in turn, affected
the global climate.

In Africa,
the lush green forest canopy

gave way
to a sparser landscape.

Some species

that were highly specialized
for life in the trees

became extinct.

But the generalists, the ones
that could find a way

to make a living no matter what
life threw at them,

endured and evolved.

Our ancestors had once
burrowed deep in the ground

to avoid predators
who stalked the surface.

But when
the dinosaurs perished,

they emerged into the daylight,

and over the eons,
made new lives

in the branches of the trees.

They developed
opposable thumbs and toes

for swinging
from branch to branch,

across the broad canopy
of treetops,

where all their needs
were fulfilled.

They could also walk upright,
but only for short distances.

With so many trees around, they
didn't have to go very far.

But then it got colder,

and the trees thinned out,

broad grasslands sprang up,
and our ancestors

were forced to traverse them
in search of food.

You needed
a totally different skill set

to make it on the savanna.

In the old days,

you could sit
perched on your tree branch

and watch the big cats
from a safe distance.

Now you were playing
on the same dangerous field.

The survivors were those
who evolved the ability

to walk great distances
on their hind legs

and to run when necessary.

This changed the way

they looked at the world.

Hands and arms were no longer
tied up with walking.

They were free to gather food
and pick up sticks and bones.

These could be used
as weapons and tools.

Think of it...

A change in the topography
of a small piece of land

half a world away
reroutes ocean currents.

Africa grows colder and drier.

Most of the trees can't
withstand the new climate.

The primates who lived in them

have to seek other homes,
and before you know it,

they're using tools
to remake the planet.

The Earth has shaped the course
of human destiny,

but so has the invisible pull
of distant worlds.

The planets have influenced

our lives,
but not in the way you think.

The gravitational pull
of Venus--

small but close--

and that of Jupiter--
distant but massive--

tilted the Earth's axis
this way and that...

and ever so slightly tweaked
the shape of its orbit.

This periodically altered

the amount of sunlight

falling on the edge
of the northern ice cap.

Sometimes it made
the summers there colder,

and the glaciers
advanced southward

from one year to the next,

grinding and scraping,

and crushing everything
in their path.

That's what we call an ice age.

At other times, changes
in Earth's axis and orbit

made the Arctic summers warmer.

And the melting glaciers
began to retreat.

Imagine how resourceful
our ancestors had to be

in order to survive these
radical changes in climate.

With each glacial period,

the ice sheets grow
at the expense of the oceans;

the world sea level falls
by more than 400 feet,

uncovering wide areas of land

along the edges
of the continents.

15 to 25,000 years ago,

there was a period
when the ice receded,

exposing a temporary
land bridge.

The gateway to the other half
of the planet swings open.

Bands of wanderers
crossed the land bridge

to North America
and parts south.

About 10,000 years ago,
the manic swings

of the climate and sea levels
came to a stop.

A new and gentler
climate age began.

It's the one we live in now.

When the great
ice sheets melted,

the sea rose
to its present height

and the rivers carried silt
from the highlands

to build great delta plains
where they met the sea.

On those fertile plains,
we learned a new way of life...

how to grow things,
to feed ourselves and more.

For most of us,
this meant an end

to a million years
of wandering.

The way the planets tug
at each other,

the way the skin
of the Earth moves,

the way those motions
affect climate

and the evolution of life
and intelligence--

they all combined
to give us the means

to turn the mud
of those river deltas

into the first civilizations.

There's nothing like
an interglacial period,

one of those balmy
intermissions in an ice age.

And the great news is that
this one is due to last

for another 50,000 years.

What a break for our kind.

Just one problem.

We can't seem to stop
burning up all those

buried trees from way back
in the Carboniferous Age,

in the form of coal;

and the remains
of ancient plankton,

in the form of oil and gas.

If we could, we'd be
home free, climate-wise.

Instead, we're dumping carbon
dioxide into the atmosphere

at a rate the Earth hasn't seen

since the great climate
catastrophes of the past,

the ones that led
to mass extinctions.

We just can't seem to break our
addiction to the kinds of fuel

that'll bring back a climate
last seen by the dinosaurs;

a climate that will drown our
coastal cities and wreak havoc

on the environment and our
ability to feed ourselves.

All the while, the glorious sun

pours immaculate,
free energy down upon us;

more than we will ever need.

Why can't we summon
the ingenuity and courage

of the generations
that came before us?

The dinosaurs never saw
that asteroid coming.

What's our excuse?

There's a corridor

in the Halls of Extinction
that is, right now,

empty and unmarked.

The autobiography of the Earth
is still being written.

There's a chance that the end
of our story lies in there.

Congratulations.

You're alive.

There's an unbroken thread
that stretches across

more than three billion years

that connects us
to the first life

that ever touched this world.

Think of how tough,
resourceful and lucky

all of our countless
ancestors must have been

to survive long enough

to pass on the message
of life to the next

and the next...

and the next generation,

hundreds of millions
of times...

before it came to us.

There were so many
rivers to cross,

so many hazards along the way.

Predators, starvation, disease,

miscalculation, long winters,

drought, flood and violence.

Not to mention
the occasional upheavals that

erupted from within our planet
and the apocalyptic bolts

that come from the blue.
No matter where we hail from

or who our parents were,
we are descended

from the hearty survivors
of unimaginable catastrophes.

Each of us is a runner in
the longest and most dangerous

relay race there ever was,

and at this moment, we hold
the baton in our hands.

The past is another planet.

And so is the future.

Some 250 million years from now,

many geologists think
that the lands of the Earth

will be united once again.

All this beauty
will have vanished

and the Earth
of our moment in time

will take its place
among the lost worlds.

The great internal engine
of plate tectonics

is indifferent to life,

as are the small changes
in the Earth's orbit and tilt

and the occasional collisions

with little worlds
on rogue orbits.

These processes have no notion
of what has been going on

over billions of years
on our planet's surface.

They do not care.

Each of us is a tiny being

riding on the outermost skin
of one of the smaller planets

for a few dozen trips
around the local star.

The things that live
the longest on Earth

endure for only
about a millionth

of the age of our planet.

So, of course,
the individual organisms

see nothing of
the overall pattern.

Of changing continents...

climate...

evolution.

That we understand
even a little of our origins

is one of the great triumphs
of human insight and courage.

Who we are and why we are here
can only be glimpsed

by piecing together
something of the full picture,

which must encompass
eons of time...

millions of species...

and a multitude of worlds.

In this perspective,
it's not surprising

that we're a mystery
to ourselves and that,

despite our
manifest pretension,

we are far from being masters
of our own little house.

This new corridor
has no name above the entrance

to designate its epoch,
and we don't yet know

which failed species will be
memorialized within its walls.

What happens here, in countless
ways, both large and small,

is being written by us.

Right now.

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