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Cosmos (1980): Season 1, Episode 1 - The Shores of the Cosmic Ocean - full transcript

Carl Sagan examines our planet's place in the universe by leading us on a journey from Earth to Deep Space.


Hello. My name is Ann Druyan.

When Carl Sagan, Steven Soter and I...

...wrote the Cosmos TV series
in the late 1970s...

...a lot of things were different.

Back then, the U.S. and the Soviet Union...

...held the hole planet
in their perpetual hostage crisis...

...called the Cold War.

The wealth and scientific ingenuity
of our civilization...

...was being squandered
on a runaway arms raise.

Then employed half the world scientists...

...and infested the world
with 50.000 nuclear weapons.

So much has happened since then.

The Cold War is history...

...and science has made great strides.

We've completed the spacecraft
recognizance of the Solar System...

...the preliminary mapping of the visible
universe that surrounds us...

...and we've charted the universe within:
the human genome.

When Cosmos was first broadcast
there was no World Wide Web...

...it was a different world.

What a tribute to Carl Sagan...

...a scientist who took many a punch
for daring to speculate...

...that even after 20 of the most eventful
years in the history of science...

...Cosmos requires few revisions
and indeed is rich in prophecy.

Cosmos is both the history
of the scientific enterprise...

...and an attempt
to convey the spiritual high...

...of its central revelation:

Our oneness with the universe.

Now, please, enjoy Cosmos,
the proud saga of how...

...through the searching of 40.000
generations of our ancestors...

...we have come to discover
our coordinates...

...in space and in time.

And how, through the awesomely
powerful method of science...

...we have been able to reconstruct
the sweep of cosmic evolution...

...and defined our own part
in its great story.

SAGAN:
The cosmos is all that is...

...or ever was or ever will be.

Our contemplations of
the cosmos stir us.

There is a tingling in the spine,
a catch in the voice...

...a faint sensation,
as if a distant memory...

...of falling from a great height.

We know we are approaching
the grandest of mysteries.

The size and age of the cosmos...

...are beyond ordinary
human understanding.

Lost somewhere between
immensity and eternity...

...is our tiny planetary home,
the Earth.

For the first time,
we have the power to decide...

...the fate of our planet
and ourselves.

This is a time of great danger.

But our species is
young and curious and brave.

It shows much promise.

In the last few millennia,
we've made...

...the most astonishing
and unexpected discoveries...

...about the cosmos
and our place within it.

I believe our future depends
powerfully on...

...how well we understand
this cosmos...

...in which we float
like a mote of dust...

...in the morning sky.

(SEAGULL CHIRPS)

We're about to begin a journey
through the cosmos.

We'll encounter galaxies and suns
and planets...

...life and consciousness...

...coming into being,
evolving and perishing.

Worlds of ice and stars of diamond.

Atoms as massive as suns...

...and universes smaller than atoms.

But it's also a story
of our own planet...

...and the plants and animals
that share it with us.

And it's a story about us:

How we achieved our present
understanding of the cosmos...

...how the cosmos has shaped
our evolution and our culture...

...and what our fate may be.

We wish to pursue the truth,
no matter where it leads.

But to find the truth, we need
imagination and skepticism both.

We will not be afraid to speculate.

But we will be careful to distinguish
speculation from fact.

The cosmos is full beyond measure
of elegant truths...

...of exquisite interrelationships...

...of the awesome machinery of nature.

The surface of the Earth is
the shore of the cosmic ocean.

On this shore, we have learned
most of what we know.

Recently, we've waded
a little way out...

...maybe ankle-deep,
and the water seems inviting.

Some part of our being knows
this is where we came from.

We long to return.

And we can.

Because the cosmos is also within us.
We're made of star-stuff.

We are a way for the cosmos
to know itself.

The journey for each of us
begins here.

We're going to explore the cosmos
in a ship of the imagination...

...unfettered by ordinary limits
on speed and size...

...drawn by the music
of cosmic harmonies...

...it can take us anywhere
in space and time.

Perfect as a snowflake...

...organic as a dandelion seed...

...it will carry us...

...to worlds of dreams
and worlds of facts.

Come with me.

Before us is the cosmos
on the grandest scale we know.

We are far from the shores of Earth...

...in the uncharted reaches
of the cosmic ocean.

Strewn like sea froth
on the waves of space...

...are innumerable
faint tendrils of light.

Some of them containing hundreds...

...of billions of suns.

These are the galaxies...

...drifting endlessly
in the great cosmic dark.

In our ship of the imagination...

...we are halfway to the edge
of the known universe.

In this, the first of
our cosmic voyages...

...we begin to explore the universe
revealed by science.

Our course will eventually carry us
to a far-off and exotic world.

But from the depths of space,
we cannot detect even...

...the cluster of galaxies
in which our Milky Way is embedded...

...much less the sun or the Earth.

We are in the realm
of the galaxies...

...8 billion light years from home.

No matter where we travel,
the patterns of nature are the same...

...as in the form
of this spiral galaxy.

The same laws of physics
apply everywhere...

...throughout the cosmos.

But we have just begun to
understand these laws.

The universe is rich in mystery.

Near the center of
a cluster of galaxies...

...there's sometimes a rogue,
elliptical galaxy...

...made of a trillion suns...

...which devours its neighbors.

Perhaps this cyclone of stars...

...is what astronomers on Earth
call a quasar.

Our ordinary measures
of distance fail us...

...here in the realm of the galaxies.

We need a much larger unit:
the light year.

It measures how far
light travels in a year...

...nearly 10 trillion kilometers.

It measures not time,
but enormous distances.

In the Hercules cluster...

...the individual galaxies are
about 300,000 light years apart.

So light takes about 300,000 years...

...to go from one galaxy to another.

Like stars and planets and people...

...galaxies are born, live and die.

They may all experience
a tumultuous adolescence.

During their first 100 million years,
their cores may explode.

Seen in radio light,
great jets of energy...

...pour out and echo
across the cosmos.

Worlds near the core or along
the jets would be incinerated.

I wonder how many planets
and how many civilizations...

...might be destroyed.

In the Pegasus cluster,
there's a ring galaxy...

...the wreckage left from
the collision of two galaxies.

A splash in the cosmic pond.

Individual galaxies may
explode and collide...

...and their constituent stars
may blow up as well.

In this supernova explosion...

...a single star outshines
the rest of its galaxy.

We are approaching what
astronomers on Earth call...

...the Local Group.

Three million light years across,
it contains some 20 galaxies.

It's a sparse and rather typical
chain of islands...

...in the immense cosmic ocean.

We are now only 2 million
light years from home.

On the maps of space,
this galaxy is called M31...

...the great galaxy Andromeda.

It's a vast storm of stars
and gas and dust.

As we pass over it...

...we see one of its small
satellite galaxies.

Clusters of galaxies...

...and the stars of
individual galaxies...

...are all held together by gravity.

Surrounding M31...

...are hundreds of globular
star clusters.

We're approaching one of them.

Each cluster orbits the massive
center of the galaxy.

Some contain up to
a million separate stars.

Every globular cluster is
like a swarm of bees...

...bound by gravity...

...every bee, a sun.

From Pegasus,
our voyage has taken us...

...200 million light years
to the Local Group...

...dominated by two
great spiral galaxies.

Beyond M31 is another
very similar galaxy.

Its spiral arms slowly turning...

...once every quarter billion years.

This is our own Milky Way...

...seen from the outside.

This is the home galaxy
of the human species.

In the obscure backwaters
of the Carina-Cygnus spiral arm...

...we humans have evolved
to consciousness...

...and some measure of understanding.

Concentrated in its brilliant core...

...and strewn along its spiral arms...

...are 400 billion suns.

It takes light 100,000 years
to travel...

...from one end of the galaxy
to the other.

Within this galaxy are
stars and worlds...

...and, it may be, an enormous
diversity of living things...

...and intelligent beings
and space faring civilizations.

Scattered among the stars
of the Milky Way...

...are supernova remnants...

...each one the remains of
a colossal stellar explosion.

These filaments of glowing gas...

...are the outer layers of a star
which has recently destroyed itself.

The gas is unraveling...

...returning star-stuff
back into space.

(PULSAR HISSES)

And at its heart, are the remains
of the original star...

...a dense, shrunken stellar
fragment called a pulsar.

A natural lighthouse,
blinking and hissing.

A sun that spins twice each second.

Pulsars keep such perfect time
that the first one discovered...

...was thought to be a sign of
extraterrestrial intelligence.

Perhaps a navigational beacon...

...for great ships that travel
across the light years...

...and between the stars.

There may be such intelligences
and such starships...

...but pulsars are not
their signature.

Instead, they are
the doleful reminders...

...that nothing lasts forever...

...that stars also die.

We continue to plummet,
falling thousands of light years...

...towards the plane of the galaxy.

This is the Milky Way...

...our galaxy seen edge on.

Billions of nuclear furnaces...

...converting matter into starlight.

Some stars are flimsy
as a soap bubble.

Others are 100 trillion times
denser than lead.

The hottest stars are
destined to die young.

But red giants are mostly elderly.

Such stars are unlikely
to have inhabited planets.

But yellow dwarf stars,
like the sun...

...are middle-aged
and they are far more common.

These stars may have
planetary systems.

And on such planets, for the first
time on our cosmic voyage...

...we encounter rare forms of matter:

Ice and rock, air and liquid water.

Close to this yellow star...

...is a small, warm, cloudy world...

...with continents and oceans.

These conditions permit an even more
precious form of matter to arise:

Life.

But this is not the Earth.

Intelligent beings have evolved
and reworked this planetary surface...

...in a massive engineering
enterprise.

In the Milky Way galaxy,
there may be many worlds...

...on which matter has
grown to consciousness.

I wonder, are they very
different from us?

What do they look like?

What are their politics, technology,
music, religion?

Or do they have patterns of culture
we can't begin to imagine?

Are they also a danger to themselves?

Among the many glowing clouds
of interstellar gas...

...is one called the Orion Nebula...

...only 1500 light years from Earth.

These three bright stars
are seen by earthlings...

...as the belt in the familiar
constellation of Orion the hunter.

The nebula appears from Earth
as a patch of light...

...the middle star in Orion's sword.

But it is not a star.

It is another thing entirely.

A cloud that veils
one of nature's secret places.

This is a stellar nursery,
a place where stars are born.

They condense by gravity
from gas and dust...

...until their temperatures become
so high that they begin to shine.

Such clouds mark
the births of stars...

...as others bear witness
to their deaths.

After stars condense in the hidden
interiors of interstellar clouds...

...what happens to them?

The Pleiades are a loose cluster
of young stars...

...only 50 million years old.

These fledgling stars are just
being let out into the galaxy.

Still surrounded by wisps
of nebulosity...

...the gas and dust
from which they formed.

There are clouds
that hang like inkblots...

...between the stars.

They are made of fine, rocky dust...

...organic matter and ice.

Inside, a few stars begin to turn on.

Nearby worlds of ice evaporate...

...and form long, comet-like tails...

...driven back by the stellar winds.

Black clouds, light years across...

...drift between the stars.

They're filled with
organic molecules.

The building blocks of life
are everywhere.

They are easily made.

On how many worlds have such complex
molecules assembled themselves...

...into patterns we would
call alive?

Most stars belong to systems
of two or three or many suns...

...bound together by gravity.

Each system is isolated
from its neighbors...

...by the light years.

We are approaching a single,
ordinary, yellow dwarf star...

...surrounded by a system
of nine planets...

...dozens of moons, thousands of
asteroids and billions of comets:

The family of the sun.

Only four light hours from Earth
is the planet Neptune...

...and its giant satellite, Triton.

Even in the outskirts
of our own solar system...

...we humans have barely begun
our explorations.

Only a century ago...

...we were ignorant even of
the existence of the planet Pluto.

Its moon, Charon, remained
undiscovered until 1978.

The rings of Uranus were
first detected in 1977.

There are new worlds to chart
even this close to home.

Saturn is a giant gas world.

If it has a solid surface...

...it must lie far below
the clouds we see.

Saturn's majestic rings...

...are made of trillions
of orbiting snowballs.

We are now only 80 light minutes
from home.

A mere one and a half
billion kilometers.

The largest planet in our
solar system is Jupiter.

On its dark side, super bolts
of lightning illuminate the clouds...

...as first revealed by
the Voyager spacecraft in 1979.

Inside the orbit of Jupiter...

...are countless shattered
and broken world-lets:

The asteroids.

These reefs and shoals...

...mark the border of
the realm of giant planets.

We are now entering the shallows
of the solar system.

Here there are worlds with thin
atmospheres and solid surfaces:

Earth-like planets...

...with landscapes crying out
for careful exploration.

This world is Mars.

In 1976, after a year's voyage...

...two robot explorers from Earth...

...landed on this alien shore.

On Mars, there is a volcano
as wide as Arizona...

...and almost three times
the height of Mount Everest.

We've named it Mount Olympus.

This is a world of wonders.

Mars is a planet with ancient
river valleys...

...and violent sandstorms driven
by winds at half the speed of sound.

There is a giant rift in its surface
5000 kilometers long.

It's called Vallis Marinaris.

The valley of
the Mariner spacecraft...

...that came to explore Mars
from a nearby world.

In this, our first cosmic voyage...

...we have just begun
the reconnaissance of Mars...

...and all those other planets
and stars and galaxies.

In voyages to come,
we will explore them more fully.

But now, we travel the few
remaining light minutes...

...to a blue and cloudy world,
third from the sun.

The end of our long journey...

...is the world where we began.

Our travels allow us...

...to see the Earth anew...

...as if we came from somewhere else.

There are a hundred billion
galaxies...

...and a billion trillion stars.

Why should this modest planet
be the only inhabited world?

To me, it seems far more likely
that the cosmos is brimming over...

...with life and intelligence.

But so far, every living thing...

...every conscious being...

...every civilization
we know anything about...

...lived there, on Earth.

Beneath these clouds...

...the drama of the human species
has been unfolded.

We have, at last, come home.

Welcome to the planet Earth.

A place with blue nitrogen skies...

...oceans of liquid water...

...cool forests...

...soft meadows.

A world positively rippling with life.

In the cosmic perspective,
it is, for the moment, unique.

The only world in which
we know with certainty...

...that the matter of the cosmos
has become alive and aware.

There must be many such worlds
scattered through space...

...but our search for them
begins here...

...with the accumulated wisdom of
the men and women of our species...

...acquired at great cost...

...over a million years.

There was once a time when
our planet seemed immense.

When it was the only world
we could explore.

Its true size was first worked out
in a simple and ingenious way...

...by a man who lived here in Egypt,
in the third century B.C.

This tower may have been
a communications tower.

Part of a network running along
the North African coast...

...by which signal bonfires were used
to communicate messages of state.

It also may have been used
as a lighthouse...

...a navigational beacon
for sailing ships...

...out there in the Mediterranean Sea.

It is about 50 kilometers west...

...of what was once one of the great
cities of the world, Alexandria.

In Alexandria, at that time...

...there lived a man named
Eratosthenes.

A competitor called him "beta," the
second letter of the Greek alphabet...

...because, he said, "Eratosthenes
was second best in everything."

But it seems clear, in many fields,
Eratosthenes was "alpha."

He was an astronomer, historian,
geographer...

...philosopher, poet, theater critic
and mathematician.

He was also the chief librarian
of the Great Library of Alexandria.

And one day while reading
a papyrus book in the library...

...he came upon a curious account.

Far to the south, he read...

...at the frontier outpost of Syene...

...something notable could be seen
on the longest day of the year.

On June 21st...

...the shadows of a temple column,
or a vertical stick...

...would grow shorter
as noon approached.

As the hours crept towards midday...

...the sun's rays would slither down
the sides of a deep well...

...which on other days
would remain in shadow.

And then, precisely at noon...

...columns would cast no shadows.

And the sun would shine directly down
into the water of the well.

At that moment...

...the sun was exactly overhead.

It was an observation that someone else
might easily have ignored.

Sticks, shadows,
reflections in wells...

...the position of the sun...

...simple, everyday matters.

Of what possible importance
might they be?

But Eratosthenes was a scientist...

...and his contemplation of these
homely matters changed the world...

...in a way, made the world.

Because Eratosthenes had
the presence of mind to experiment...

...to actually ask whether
back here, near Alexandria...

...a stick cast a shadow
near noon on June the 21 st.

And it turns out, sticks do.

An overly skeptical person
might have said...

...that the report from Syene
was an error.

But it's an absolutely
straightforward observation.

Why would anyone lie
on such a trivial matter?

Eratosthenes asked himself
how it could be...

...that at the same moment...

...a stick in Syene
would cast no shadow...

...and a stick in Alexandria,
800 kilometers to the north...

...would cast a very definite shadow.

Here is a map of ancient Egypt.

I've inserted two sticks, or obelisks.

One up here in Alexandria
and one down here in Syene.

Now, if at a certain moment
each stick casts...

...no shadow, no shadow at all...

...that's perfectly easy to understand,
provided the Earth is flat.

If the shadow at Syene is
at a certain length...

...and the shadow at Alexandria is
the same length...

...that also makes sense
on a flat Earth.

But how could it be,
Eratosthenes asked...

...that at the same instant
there was no shadow at Syene...

...and a very substantial shadow
at Alexandria?

The only answer was that
the surface of the Earth is curved.

Not only that...

...but the greater the curvature,
the bigger the difference...

...in the lengths of the shadows.
The sun is so far away...

...that its rays are parallel
when they reach the Earth.

Sticks at different angles to the sun
will cast shadows at different lengths.

For the observed difference
in the shadow lengths...

...the distance between
Alexandria and Syene...

...had to be about seven degrees
along the surface of the Earth.

By that, I mean, if you would imagine
these sticks extending...

...all the way down
to the center of the Earth...

...they would there intersect
at an angle of seven degrees.

Well, seven degrees is
something like a 50th...

...of the full circumference
of the Earth, 360 degrees.

Eratosthenes knew the distance
between Alexandria and Syene.

He knew it was 800 kilometers.

Why? Because he hired a man
to pace out the entire distance...

...so that he could perform
the calculation I'm talking about.

Now, 800 kilometers times 50
is 40,000 kilometers.

That must be the circumference
of the Earth.

That's how far it is to go
once around the Earth.

That's the right answer.

Eratosthenes' only tools were...

...sticks, eyes, feet and brains.

Plus a zest for experiment.

With those tools, he correctly deduced
the circumference of the Earth...

...to high precision with an error
of only a few percent.

That's pretty good figuring
for 2200 years ago.

Then, as now, the Mediterranean was
teeming with ships.

Merchantmen, fishing vessels,
naval flotillas.

But there were also
courageous voyages into the unknown.

400 years before Eratosthenes,
Africa was circumnavigated...

...by a Phoenician fleet
in the employ...

...of the Egyptian pharaoh Necho.

They set sail...

...probably in boats as frail
and open as these...

...out from the Red Sea,
down the east coast of Africa...

...up into the Atlantic and then
back through the Mediterranean.

That epic journey took three years...

...about as long as
it takes Voyager...

...to journey from Earth to Saturn.

After Eratosthenes,
some may have attempted...

...to circumnavigate the Earth.

But until the time of Magellan,
no one succeeded.

What tales of adventure and daring...

...must earlier have been told...

...as sailors and navigators,
practical men of the world...

...gambled their lives
on the mathematics...

...of a scientist
from ancient Alexandria.

Today, Alexandria shows few traces
of its ancient glory...

...of the days when Eratosthenes
walked its broad avenues.

Over the centuries, waves of conquerors
converted its palaces and temples...

...into castles and churches,
then into minarets and mosques.

The city was chosen to be the capital
of his empire by Alexander the Great...

...on a winter's afternoon in 331 B.C.

A century later, it had become
the greatest city of the world.

Each successive civilization
has left its mark.

But what now remains of the
marvel city of Alexander's dream?

Alexandria is still
a thriving marketplace...

...still a crossroads
for the peoples of the Near East.

But once, it was radiant
with self-confidence...

...certain of its power.

Can you recapture a vanished epoch...

...from a few broken statues and scraps
of ancient manuscripts?

In Alexandria, there was
an immense library...

...and an associated
research institute.

And in them worked the finest minds
in the ancient world.

(CAN CLUNKS)

(DOOR SQUEAKS)

Of that legendary library...

...all that survives is this...

...dank and forgotten cellar.

It's in the library annex,
the Serapeum...

...which was once a temple...

...but was later reconsecrated
to knowledge.

These few moldering shelves...

...probably once in a basement
storage room...

...are its only physical remains.

But this place was once...

...the brain and glory...

...of the greatest city
on the planet Earth.

If I could travel back into time...

...this is the place I would visit.

The Library of Alexandria
at its height, 2000 years ago.

Here, in an important sense...

...began the intellectual adventure
which has led us into space.

All the knowledge in the ancient world
was once within these marble walls.

In the great hall, there may have
been a mural of Alexander...

...with the crook and flail
and ceremonial headdress...

...of the pharaohs of ancient Egypt.

This library was a citadel
of human consciousness...

...a beacon on our journey
to the stars.

It was the first true research
institute in the history of the world.

And what did they study?

They studied everything.
The entire cosmos.

"Cosmos" is a Greek word
for the order of the universe.

In a way, it's the opposite of chaos.

It implies a deep interconnectedness
of all things.

The intricate and subtle way
that the universe is put together.

Genius flourished here.

In addition to Eratosthenes,
there was the astronomer Hipparchus...

...who mapped the constellation...

...and established the brightness
of the stars.

And there was Euclid...

...who brilliantly
systematized geometry...

...who told his king,
who was struggling...

...with some difficult problem
in mathematics...

...that there was no royal road
to geometry.

There was Dionysius of Thrace,
the man who defined...

...the parts of speech:
nouns, verbs and so on...

...who did for language, in a way,
what Euclid did for geometry.

There was Herophilus,
a physiologist who identified...

...the brain rather than the heart
as the seat of intelligence.

There was Archimedes,
the greatest mechanical genius...

...until the time
of Leonardo da Vinci.

And there was the astronomer Ptolemy,
who compiled much of what today is...

...the pseudoscience of astrology.

His Earth-centered universe...

...held sway for 1500 years...

...showing that intellectual brilliance
is no guarantee...

...against being dead wrong.

And among these great men,
there was also a great woman.

Her name was Hypatia.

She was a mathematician
and an astronomer...

...the last light of the library...

...whose martyrdom is bound up with
the destruction of this place...

...seven centuries after
it was founded.

Look at this place.

The Greek kings of Egypt
who succeeded Alexander...

...regarded advances in science,
literature and medicine...

...as among the treasures
of the empire.

For centuries, they generously
supported research and scholarship.

An enlightenment shared by
few heads of state, then or now.

(FOUNTAIN GURGLES)

Off this great hall were
10 large research laboratories.

There were fountains and colonnades,
botanical gardens...

...and even a zoo with animals
from India and sub-Saharan Africa.

There were dissecting rooms
and an astronomical observatory.

But the treasure of the library...

...consecrated to the god Serapis...

...built in the city of Alexander...

...was its collection of books.

The organizers of the library combed...

...all the cultures and languages
of the world for books.

They sent agents abroad
to buy up libraries.

Commercial ships docking in Alexandria
harbor were searched by the police...

...not for contraband, but for books.

The scrolls were borrowed, copied
and returned to their owners.

Until studied, these scrolls were
collected in great stacks...

...called, "books from the ships."

Accurate numbers are
difficult to come by...

...but it seems that the library
contained at its peak...

...nearly one million scrolls.

The papyrus reed grows in Egypt.

It's the origin of our word
for "paper."

Each of those million volumes
which once existed in this library...

...were handwritten
on papyrus manuscript scrolls.

What happened to all those books?

The classical civilization
that created them disintegrated.

The library itself was destroyed.

Only a small fraction
of the works survived.

And as for the rest,
we're left only with pathetic...

...scattered fragments.

But how tantalizing those remaining
bits and pieces are.

For example, we know
that there once existed here...

...a book by the astronomer
Aristarchus of Samos...

...who apparently argued that
the Earth was one of the planets...

...that, like the other planets,
it orbits the sun...

...and that the stars are
enormously far away.

All absolutely correct.

But we had to wait
nearly 2000 years...

...for these facts to be rediscovered.

The astronomy stacks
of the Alexandria Library.

Hipparchus.

Ptolomeus. Here we are.

Aristarchus.

This is the book.

How I'd love to be able
to read this book...

...to know how Aristarchus
figured it out.

But it's gone. Utterly and forever.

If we multiply our sense of loss
for this work of Aristarchus...

...by 100,000...

...we begin to appreciate
the grandeur...

...of the achievement
of classical civilization...

...and the tragedy of its destruction.

We have far surpassed the science
known to the ancient world...

...but there are irreparable gaps
in our historical knowledge.

Imagine what mysteries of the past
could be solved...

...with a borrower's card
to this library.

For example, we know of a three-volume
history of the world...

...now lost, written by
a Babylonian priest named Berossus.

Volume I dealt with the interval
from the creation of the world...

...to the Great Flood.

A period that he took
to be 432,000 years...

...or about 100 times longer than
the Old Testament chronology.

What wonders were in
the books of Berossus!

But why have I brought you
across 2000 years...

...to the Library of Alexandria?

Because this was when and where
we humans...

...first collected
seriously and systematically...

...the knowledge of the world.

This is the Earth
as Eratosthenes knew it.

A tiny, spherical world, afloat...

...in an immensity of space and time.

We were, at long last,
beginning to find...

...our true bearings in the cosmos.

The scientists of antiquity...

...took the first and most
important steps in that direction...

...before their civilization
fell apart.

But after the Dark Ages,
it was by and large...

...the rediscovery of the works
of these scholars done here...

...that made
the Renaissance possible...

...and thereby powerfully influenced
our own culture.

When, in the 15th century,
Europe was at last ready...

...to awaken from its long sleep...

...it picked up some of the tools,
the books and the concepts...

...laid down here more than
a thousand years before.

By 1600, the long-forgotten ideas
of Aristarchus...

...had been rediscovered.

Johannes Kepler constructed
elaborate models...

...to understand the motion
and arrangement of the planets...

...the clockwork of the heavens.

And at night, he dreamt
of traveling to the moon.

His principal
scientific tools were...

...the mathematics
of the Alexandrian Library...

...and an unswerving respect
for the facts...

...however disquieting they might be.

His story, and the story of
the scientists who came after him...

...are also part of our voyage.

Seventy years later,
the sun-centered universe...

...of Aristarchus and Copernicus...

...was widely accepted
in the Europe of the Enlightenment.

The idea arose that the planets
were worlds...

...governed by laws of nature...

...and scientific speculation turned
to the motions of the stars.

The clockwork in the heavens
was imitated...

...by the watchmakers of Earth.

Precise timekeeping permitted
great sailing ship voyages...

...of exploration and discovery...

...which bound up the Earth.

This was a time when free inquiry...

...was valued once again.

(SPEAKING IN FOREIGN LANGUAGE)

250 years later,
the Earth was all explored.

New adventurers now looked to
the planets and the stars.

The galaxies were recognized
as great aggregates of stars...

...island universes
millions of light years away.

In the 1920s, astronomers had
begun to measure...

...the speeds of distant galaxies.

ASTRONOMER 1:
What time is it?

7:15.

ASTRONOMER 1:
Lights off, please.

They found that the galaxies were
flying away from one another.

To the astonishment of everyone...

...the entire universe was expanding.

We had begun to plumb the true depths
of time and space.

The long, collective enterprise
of science...

...has revealed a universe
some 15 billion years old.

The time since the explosive
birth of the cosmos...

...the big bang.

(THUNDER CRASHES)

The cosmic calendar compresses
the local history of the universe...

...into a single year.

If the universe began
on January 1st...

...it was not until May
that the Milky Way formed.

Other planetary systems
may have appeared...

...in June, July and August...

...but our sun and Earth,
not until mid-September.

Life arose soon after.

Everything humans have ever done
occurred in that bright speck...

...at the lower right
of the cosmic calendar.

The big bang is at upper left...

...in the first second of January 1st.

Fifteen billion years later
is our present time...

...the last second of December 31st.

Every month is
1 billion years long.

Each day represents 40 million years.

Each second stands for some 500 years
of our history.

The blinking of an eye
in the drama of cosmic time.

At this scale, the cosmic calendar
is the size of a football field...

...but all of human history
would occupy an area...

...the size of my hand.

We're just beginning to trace
the long and tortuous path...

...which began with
the primeval fireball...

...and led to the condensation
of matter:

Gas, dust, stars, galaxies, and...

...at least in our little nook
of the universe...

...planets, life, intelligence
and inquisitive men and women.

We've emerged so recently...

...that the familiar events
of our recorded history...

...occupy only the last seconds
of the last minute of December 31st.

But some critical events for the
human species began much earlier...

...minutes earlier.

So we change our scale
from months to minutes.

Down here, the first humans
made their debut...

...around 10:30 p.m. on December 31st.

And with the passing
of every cosmic minute...

...each minute 30,000 years long...

...we began the arduous journey
towards understanding...

...where we live and who we are.

11:46...

...only 14 minutes ago...

...humans have tamed fire.

11:59:20, the evening
of the last day of the cosmic year...

...the 11th hour, the 59th minute,
the 20th second...

...the domestication of
plants and animals begins:

An application of the human talent...

...for making tools.

11:59:35, settled agricultural
communities...

...evolved into the first cities.

We humans appear on
the comic calendar so recently...

...that our recorded history
occupies only...

...the last few seconds of
the last minute of December 31 st.

In the vast ocean of time
which this calendar represents...

...all our memories are confined...

...to this small square.

Every person we've ever heard of
lived somewhere in there.

All those kings and battles, migrations
and inventions, wars and loves.

Everything in the history books...

...happens here...

...in the last 10 seconds
of the cosmic calendar.

We on Earth have just awakened...

...to the great oceans
of space and time...

...from which we have emerged.

We are the legacy...

...of 15 billion years
of cosmic evolution.

We have a choice:

We can enhance life and come to know
the universe that made us...

...or we can squander
our 15 billion-year heritage...

...in meaningless self-destruction.

What happens in the first second
of the next cosmic year...

...depends on what we do,
here and now...

...with our intelligence...

...and our knowledge of the cosmos.