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00:00:00Hello, my name is Anne Drianne.
00:00:11When Carl Sagan, Steven Soder, and I wrote the Cosmos television series in the late 1970s,
00:00:17a lot of things were different.
00:00:19Back then, the United States and the Soviet Union held the whole planet in a perpetual hostage crisis called the Cold War.
00:00:26The wealth and scientific ingenuity of our civilization was being squandered on a runaway arms race
00:00:32that employed more than half the world's scientists and infested the Earth with 50,000 nuclear weapons.
00:00:41So much has happened since then. The Cold War is history, and science has made great strides.
00:00:48We've completed the spacecraft reconnaissance of the solar system,
00:00:52the preliminary mapping of the visible universe that surrounds us,
00:00:56and we have charted the universe within, the human genome.
00:01:01When Cosmos was first broadcast, there was no World Wide Web. It was a different world.
00:01:07What a tribute to Carl Sagan, a scientist who took many a punch for daring to speculate
00:01:13that even after 20 of the most eventful years in the history of science,
00:01:18Cosmos requires few revisions and indeed is rich in prophecy.
00:01:24Cosmos is both a history of the scientific enterprise and an attempt to convey the soaring spiritual high of its central revelation,
00:01:34our oneness with the universe.
00:01:37Now please enjoy Cosmos, the proud saga of how, through the searching of 40,000 generations of our ancestors,
00:01:46we have come to discover our coordinates in space and in time,
00:01:51and how, through the awesomely powerful method of science,
00:01:56we have been able to reconstruct the sweep of cosmic evolution,
00:02:00and to find our own part in its great story.
00:02:05All this time is a great story,
00:02:08and to find the most interchangeable,
00:02:09and to find the most historical,
00:02:10and to find the most attractive,
00:02:11and to find the most miraculous knew it.
00:02:14The wonderful song of the nature,
00:02:16is the only지는 the Panther,
00:02:18we have come to discover our own part of the path,
00:02:19and this is the only one of the victims.
00:02:22We have come to share our own part,
00:02:23while we have to find the most attractive,
00:02:24isn't enough possible?
00:02:26The people who have come to understand the truth of this life and the human life,
00:02:28they have come to live with us as well.
00:02:30The people already have come to discover our own part of this life.
00:02:32If the world's largest confidence and the way
00:03:03The cosmos is all that is, or ever was, or ever will be.
00:03:22Our contemplations of the cosmos stir us.
00:03:25There 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.
00:03:37We know we are approaching the grandest atmospheres.
00:03:41The size and age of the cosmos are beyond ordinary human understanding.
00:03:52Lost somewhere between humensity and eternity is our tiny planetary home, the Earth.
00:03:59For the first time, we have the power to decide the fate of our planet and ourselves.
00:04:06This is a time of great danger, but our species is young and curious and brave.
00:04:13It shows much promise.
00:04:14In the last few millennia, we have made the most astonishing and unexpected discoveries about the cosmos and our place within it.
00:04:23I 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.
00:04:33We are about to begin a journey through the cosmos.
00:04:44We will encounter galaxies and suns and planets, life and consciousness, coming into being, evolving and perishing.
00:04:53Worlds of ice and stars of diamond, atoms as massive as suns and universes smaller than atoms.
00:05:03But it's also a story of our own planet and the plants and animals that share it with us.
00:05:09And it's a story about us, how we achieved our present understanding of the cosmos,
00:05:15how the cosmos has shaped our evolution and our culture, and what our fate may be.
00:05:23We wish to pursue the truth no matter where it leads.
00:05:29But to find the truth, we need imagination and skepticism both.
00:05:34We will not be afraid to speculate, but we will be careful to distinguish speculation from fact.
00:05:41The cosmos is full beyond measure of elegant truths, of exquisite interrelationships, of the awesome machinery of nature.
00:05:51The surface of the earth is the shore of the cosmic ocean.
00:05:57On this shore, we've learned most of what we know.
00:06:01Recently, we've waded a little way out, maybe ankle deep, and the water seems inviting.
00:06:07Some part of our being knows this is where we came from.
00:06:13We long to return.
00:06:16And we can, because the cosmos is also within us.
00:06:20We're made of star stuff.
00:06:22We are a way for the cosmos to know itself.
00:06:26The journey for each of us begins here.
00:06:28We'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.
00:06:41It can take us anywhere in space and time.
00:06:44Perfect as a snowflake, organic as a dandelion seed, it will carry us to worlds of dreams and worlds of facts.
00:06:55Please, come with me.
00:07:08Before us is the cosmos on the grandest scale we know.
00:07:13We are far from the shores of earth, in the uncharted reaches of the cosmic ocean.
00:07:25Strewn like sea froth on the waves of space are innumerable faint tendrils of light,
00:07:32some of them containing hundreds of billions of suns.
00:07:37These are the galaxies, drifting endlessly in the great cosmic dark.
00:07:47In our ship of the imagination, we are halfway to the edge of the known universe.
00:07:52In this, the first of our cosmic voyages, we begin to explore the universe revealed by science.
00:08:10Our course will eventually carry us to a far-off and exotic world.
00:08:23But from the depths of space, we cannot detect even the cluster of galaxies in which our Milky Way is embedded,
00:08:30much less the sun or the earth.
00:08:32We are in the realm of the galaxies, 8 billion light-years from home.
00:08:54No matter where we travel, the patterns of nature are the same as in the form of this spiral galaxy.
00:09:10The same laws of physics apply everywhere, throughout the cosmos.
00:09:14But we have just begun to understand these laws.
00:09:24The universe is rich in mystery.
00:09:32Near the center of a cluster of galaxies, there's sometimes a rogue, elliptical galaxy,
00:09:39made of a trillion suns, which devours its neighbors.
00:09:43Perhaps this cyclone of stars is what astronomers on Earth call a quasar.
00:10:05Our ordinary measures of distance fail us here in the realm of the galaxies.
00:10:11We need a much larger unit, the light-year.
00:10:15It measures how far light travels in a year, nearly 10 trillion kilometers.
00:10:21It measures not time, but enormous distances.
00:10:24In the Hercules cluster, the individual galaxies are about 300,000 light-years apart.
00:10:45So, light takes about 300,000 years to go from one galaxy to another.
00:10:56Like stars and planets and people, galaxies are born, live, and die.
00:11:03They may all experience a tumultuous adolescence.
00:11:08During their first hundred million years, their cores may explode.
00:11:13Seen in radio light, great jets of energy pour out and echo across the cosmos.
00:11:19Worlds near the core, or along the jets, would be incinerated.
00:11:25I wonder how many planets and how many civilizations might be destroyed.
00:11:31In the Pegasus cluster, there's a ring galaxy, the wreckage left from the collision of two galaxies,
00:11:47a splash in the cosmic pond.
00:11:50Individual galaxies may explode and collide, and their constituent stars may blow up as well.
00:11:59In this supernova explosion, a single star outshines the rest of its galaxy.
00:12:05We are approaching what astronomers on Earth call the local group.
00:12:16Three million light-years across, it contains some 20 galaxies.
00:12:22It's a sparse and rather typical chain of islands in the immense cosmic ocean.
00:12:28We are now only two million light-years from home.
00:12:33On the maps of space, this galaxy is called M31, the great galaxy in Andromeda.
00:12:41It's a vast storm of stars and gas and dust.
00:12:45As we pass over it, we see one of its small satellite galaxies.
00:12:49Clusters of galaxies and the stars of individual galaxies are all held together by gravity.
00:13:02Surrounding M31 are hundreds of globular star clusters.
00:13:08We're approaching one of them.
00:13:11Each cluster orbits the massive center of the galaxy.
00:13:15Some contain up to a million separate stars.
00:13:19Every globular cluster is like a swarm of bees, bound by gravity.
00:13:25Every bee, a sun.
00:13:30From the Pegasus cluster, our voyage has taken us 200 million light-years
00:13:34to the local group, dominated by two great spiral galaxies.
00:13:42Beyond M31 is another very similar galaxy,
00:13:46its spiral arms slowly turning once every quarter billion years.
00:13:57This is our own Milky Way, seen from the outside.
00:14:03This is the home galaxy of the human species.
00:14:14This is the home galaxy of the human species.
00:14:14In the obscure backwaters of the Carina Cygnus spiral arm,
00:14:27we humans have evolved to consciousness and some measure of understanding.
00:14:33Concentrated in its brilliant core and strewn along its spiral arms
00:14:47are 400 billion suns.
00:14:51It takes light 100,000 years to travel from one end of the galaxy to the other.
00:15:02Within this galaxy are stars and worlds,
00:15:06and it may be an enormous diversity of living things
00:15:11and intelligent beings and space-faring civilizations.
00:15:23Scattered among the stars of Milky Way are supernova remnants,
00:15:29each one the remains of a colossal stellar explosion.
00:15:32These filaments of glowing gas are the outer layers of a star
00:15:37which has recently destroyed itself.
00:15:40The gas is unraveling, returning star stuff back into space.
00:15:49And at its heart are the remains of the original star,
00:15:53a dense, shrunken, stellar fragment called a pulsar,
00:15:57a natural lighthouse, blinking and hissing,
00:16:01a sun that spins twice each second.
00:16:11Pulsars keep such perfect time
00:16:13that the first one discovered was thought to be a sign
00:16:15of extraterrestrial intelligence,
00:16:17perhaps a navigational beacon
00:16:19for great ships that travel across the light years
00:16:23and between the stars.
00:16:27There may be such intelligences and such starships,
00:16:32but pulsars are not their signature.
00:16:46Instead, they are the doleful reminders
00:16:50that nothing lasts forever,
00:16:52that stars also die.
00:16:57We continue to plummet,
00:16:59falling thousands of light years
00:17:01towards the plane of the galaxy.
00:17:06This is the Milky Way,
00:17:09our galaxy seen edge on,
00:17:11billions of nuclear furnaces
00:17:13converting matter into starlight.
00:17:16Some stars are flimsy as a soap bubble.
00:17:25Others are a hundred trillion times denser than lead.
00:17:29The hottest stars are destined to die young.
00:17:33But red giants are mostly elderly.
00:17:37Such stars are unlikely to have inhabited planets.
00:17:40But yellow dwarf stars,
00:17:45like the sun,
00:17:46are middle-aged,
00:17:48and they are far more common.
00:17:51These stars may have planetary systems,
00:17:54and on such planets,
00:17:55for the first time in our cosmic voyage,
00:17:58we encounter rare forms of matter,
00:18:01ice and rock,
00:18:03air and liquid water.
00:18:04Close to this yellow star
00:18:12is a small, warm, cloudy world
00:18:15with continents and oceans.
00:18:18These conditions permit
00:18:19an even more precious form of matter
00:18:21to arise,
00:18:23life.
00:18:23But this is not the Earth.
00:18:34Intelligent beings have evolved
00:18:35and reworked this planetary surface
00:18:38in a massive engineering enterprise.
00:18:41In the Milky Way galaxy,
00:18:43there may be many worlds
00:18:45on which matter has grown to consciousness.
00:18:47I wonder,
00:18:57are they very different from us?
00:18:59What do they look like?
00:19:01What are their politics,
00:19:02technology, music, religion?
00:19:05Or do they have patterns of culture
00:19:07we can't begin to imagine?
00:19:10Are they also a danger to themselves?
00:19:13Among the many glowing clouds
00:19:23of interstellar gas
00:19:24is one called the Orion Nebula,
00:19:28only 1,500 light years from Earth.
00:19:36These three bright stars
00:19:38are seen by Earthlings
00:19:40as the belt in the familiar constellation
00:19:42of Orion the Hunter.
00:19:51The nebula appears from Earth
00:19:53as a patch of light,
00:19:55the middle star
00:19:57in Orion's sword.
00:20:07But it is not a star.
00:20:10It is another thing entirely.
00:20:12A cloud that veils
00:20:14one of nature's secret places.
00:20:26This is a stellar nursery,
00:20:29a place where stars are born.
00:20:32They condense by gravity
00:20:33from gas and dust
00:20:34until their temperatures
00:20:36become so high
00:20:37that they begin to shine.
00:20:39Such clouds mark the births of stars
00:20:43as others bear witness
00:20:44to their deaths.
00:20:52And after stars condense
00:20:54in the hidden interiors
00:20:55of interstellar clouds,
00:20:56what happens to them?
00:20:58The Pleiades
00:20:59are a loose cluster
00:21:01of young stars
00:21:02only 50 million years old.
00:21:04These fledgling stars
00:21:06are just being let out
00:21:08into the galaxy,
00:21:10still surrounded
00:21:10by wisps of nebulosity,
00:21:13the gas and dust
00:21:14from which they formed.
00:21:16And after all knows the sky
00:21:28of the night,
00:21:32the sky is ad Career
00:21:33and billdoes
00:21:34ever
00:21:34at home.
00:21:34And his你是
00:21:35by the planet
00:21:35found on the side
00:21:36of the sky is
00:21:37the Free
00:21:42There are clouds that hang like inkblots between the stars.
00:21:56They are made of fine rocky dust, organic matter and ice.
00:22:04Inside, a few stars begin to turn on.
00:22:08Nearby worlds of ice evaporate and form long comet-like tails driven back by the stellar winds.
00:22:20Black clouds, light years across, drift between the stars.
00:22:26They're filled with organic molecules.
00:22:29The building blocks of life are everywhere.
00:22:32They're easily made.
00:22:34On how many worlds have such complex molecules assembled themselves into patterns we would call alive?
00:22:48Most stars belong to systems of two or three or many suns bound together by gravity.
00:22:56Each system is isolated from its neighbors by the light years.
00:23:02We 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.
00:23:18Only four light hours from Earth is the planet Neptune and its giant satellite Triton.
00:23:30Even in the outskirts of our own solar system, we humans have barely begun our explorations.
00:23:39Only a century ago, we were ignorant even of the existence of the planet Pluto.
00:23:45Its moon Charon remained undiscovered until 1978.
00:23:53The rings of Uranus were first detected in 1977.
00:23:59There are new worlds to chart even this close to home.
00:24:07Saturn is a giant gas world.
00:24:10If it has a solid surface, it must lie far below the clouds we see.
00:24:16Saturn's majestic rings are made of trillions of orbiting snowballs.
00:24:29We are now only 80 light minutes from home.
00:24:33A mere one and a half billion kilometers.
00:24:36The largest planet in our solar system is Jupiter.
00:24:55On its dark side, super bolts of lightning illuminate the clouds as first revealed by the Voyager spacecraft in 1979.
00:25:06A mere one and a half billion miles from Earth.
00:25:09A mere one and a half billion miles from Earth.
00:25:16Inside the orbit of Jupiter are countless shattered and broken worldlets, the asteroids.
00:25:23These reefs and shoals mark the border of the realm of giant planets.
00:25:29We are now entering the shallows of the solar system.
00:25:34Here, there are worlds with thin atmospheres and solid surfaces.
00:25:40Earth-like planets with landscapes crying out for careful exploration.
00:25:45This world is Mars.
00:25:48In 1976, after a year's voyage, two robot explorers from Earth landed on this alien shore.
00:25:59On Mars, there is a volcano as wide as Arizona and almost three times the height of Mount Everest.
00:26:09We've named it Mount Olympus.
00:26:12Mars.
00:26:13This is a world of wonders.
00:26:19Mars is a planet with ancient river valleys and violent sandstorms driven by winds at half the speed of sound.
00:26:29There is a giant rift in its surface, 5,000 kilometers long.
00:26:42It's called Valles Marinaris, the Valley of the Mariner spacecraft that came to explore Mars from a nearby world.
00:26:51In this, our first cosmic voyage, we have just begun the reconnaissance of Mars and all those other planets and stars and galaxies.
00:27:06In voyages to come, we will explore them more fully.
00:27:31But now, we travel the few remaining light minutes to a blue and cloudy world third from the sun.
00:27:41The end of our long journey is the world where we began.
00:27:46Our travels allow us to see the Earth anew as if we came from somewhere else.
00:27:53There are a hundred billion galaxies and a billion trillion stars.
00:28:02Why should this modest planet be the only inhabited world?
00:28:07To me, it seems far more likely that the cosmos is brimming over with life and intelligence.
00:28:14But so far, every living thing, every conscious being, every civilization we know anything about lived there on Earth.
00:28:32Beneath these clouds, the drama of the human species has been unfolding.
00:28:37We have, at last, come home.
00:28:41Welcome to the planet Earth.
00:28:55A place with blue nitrogen skies, oceans of liquid water, cool forests, soft meadows, a world positively rippling with life.
00:29:07In the cosmic perspective, it is, for the moment, unique.
00:29:11The only world in which we know, with certainty, that the matter of the cosmos has become alive and aware.
00:29:18There must be many such worlds scattered through space, but our search for them begins here,
00:29:24with the accumulated wisdom of the men and women of our species, acquired at great cost over a million years.
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00:30:00There was once a time when our little planet seemed immense, when it was the only world we could explore.
00:30:21Its true size was first worked out in a simple and ingenious way by a man who lived here in Egypt in the 3rd century BC.
00:30:30This 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.
00:30:48It also may have been used as a lighthouse, a navigational beacon for sailing ships out there in the Mediterranean Sea.
00:30:59It is about 50 kilometers west of what was once one of the great cities of the world, Alexandria.
00:31:06In Alexandria, at that time, there lived a man named Eratosthenes.
00:31:13One of his envious contemporaries called him Beta, the second letter of the Greek alphabet, because he said Eratosthenes was second best in the world in everything.
00:31:22But it seems clear that, in many fields, Eratosthenes was alpha.
00:31:28He was an astronomer, historian, geographer, philosopher, poet, theater critic, and mathematician.
00:31:35He was also the chief librarian of the great library of Alexandria.
00:31:39And one day, while reading a papyrus book in the library, he came upon a curious account.
00:31:48Far to the south, he read, at the frontier outpost of Syene, something notable could be seen on the longest day of the year.
00:32:09On June 21st, the shadows of a temple column or a vertical stick would grow shorter as noon approached.
00:32:18And 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.
00:32:38And then, precisely at noon, columns would cast no shadows, and the sun would shine directly down into the water of the well.
00:32:48At that moment, the sun was exactly overhead.
00:32:58It was an observation that someone else might easily have ignored.
00:33:09Sticks, shadows, reflections in wells, the position of the sun.
00:33:14But Eratosthenes was a scientist, and his contemplation of these homely matters changed the world, in a way, made the world.
00:33:29Because 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 21st.
00:33:43And it turns out, sticks do.
00:33:45An overly skeptical person might have said that the report from Syene was in error, but it's an absolutely straightforward observation.
00:33:57Why would anyone lie on such trivial matter?
00:34:00Eratosthenes 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.
00:34:14Here's a map of ancient Egypt, I've inserted two sticks, or obelisks, one up here in Alexandria, and one down here in Syene.
00:34:30Now, 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.
00:34:42If 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.
00:34:50But how could it be, Eratosthenes asked, that at the same instant, there was no shadow at Syene, and a very substantial shadow at Alexandria?
00:35:05The only answer was that the surface of the earth is curved.
00:35:10Not only that, but the greater the curvature, the bigger the difference in the lengths of the shadows.
00:35:17The sun is so far away, that its rays are parallel when they reach the earth.
00:35:22Sticks at different angles to the sun's rays will cast shadows at different lengths.
00:35:26For the observed difference in these shadow lengths, the distance between Alexandria and Syene had to be about seven degrees along the surface of the earth.
00:35:37By that I mean, if you imagine these sticks extending all the way down to the center of the earth,
00:35:43they would there intersect at an angle of about seven degrees.
00:35:47Well, seven degrees is something like a fiftieth of the full circumference of the earth, 360 degrees.
00:35:54Eratosthenes knew the distance between Alexandria and Syene, he knew it was 800 kilometers.
00:36:01Why? Because he hired a man to pace out the entire distance so that he could perform the calculation I'm talking about.
00:36:08Now, 800 kilometers times 50 is 40,000 kilometers.
00:36:14So that must be the circumference of the earth.
00:36:16That's how far it is to go once around the earth.
00:36:19That's the right answer.
00:36:21Eratosthenes' only tools were sticks, eyes, feet and brains, plus a zest for experiment.
00:36:31With those tools, he correctly deduced the circumference of the earth to high precision with an error of only a few percent.
00:36:41That's pretty good figuring for 2200 years ago.
00:36:47Then, as now, the Mediterranean was teeming with ships, merchantmen, fishing vessels, naval flotillas.
00:37:05But there were also courageous voyages into the unknown.
00:37:09400 years before Eratosthenes, Africa was circumnavigated by a Phoenician fleet in the employ of the Egyptian pharaoh Necco.
00:37:21They 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.
00:37:34That epic journey took three years, about as long as it takes Voyager to journey from earth to Saturn.
00:37:43After Eratosthenes, some may have attempted to circumnavigate the earth.
00:37:49But until the time of Magellan, no one succeeded.
00:37:52What tales of adventure and daring must earlier have been told as sailors and navigators, practical men of the world,
00:38:02gamble their lives on the mathematics of a scientist from ancient Alexandria?
00:38:09Today, Alexandria shows few traces of its ancient glory, of the days when Eratosthenes walked its broad avenues.
00:38:23Over the centuries, waves of conquerors converted its palaces and temples into castles and churches, then into minarets and mosques.
00:38:32The city was chosen to be the capital of his empire, by Alexander the Great, on a winter's afternoon in 331 BC.
00:38:43A century later, it had become the greatest city of the world.
00:38:47Each successive civilization has left its mark.
00:38:51But what now remains of the marble city of Alexander's dream?
00:39:03Alexandria is still a thriving marketplace, still a crossroads for the peoples of the Near East.
00:39:16At once, it was radiant with self-confidence, certain of its power.
00:39:28Can you recapture a vanished epoch from a few broken statues and scraps of ancient manuscripts?
00:39:42In Alexandria, there was an immense library and an associated research institute.
00:39:48And in them worked the finest mines in the ancient world.
00:40:12Of that legendary library, all that survives is this dank and forgotten cellar.
00:40:22It's in the library annex, the Serapeum, which was once a temple, but was later re-consecrated to knowledge.
00:40:31These few moldering shelves, probably once in a basement storage room, are its only physical remains.
00:40:41But this place was once the brain and glory of the greatest city on the planet Earth.
00:40:51If I could travel back into time, this is the place I would visit.
00:41:04The library of Alexandria at its height 2,000 years ago.
00:41:10Here, in an important sense, began the intellectual adventure which has led us into space.
00:41:28All the knowledge in the ancient world was once within these marble walls.
00:41:39In 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.
00:41:52This library was a citadel of human consciousness, a beacon on our journey to the stars.
00:42:04This is the largest true research institute in the history of the world.
00:42:08And what did they study?
00:42:10They studied everything.
00:42:12The entire cosmos.
00:42:14Cosmos is a Greek word for the order of the universe.
00:42:19In a way, it's the opposite of chaos.
00:42:22It implies a deep interconnectedness of all things.
00:42:27The intricate and subtle way that the universe is put together.
00:42:32Genius flourished here.
00:42:36In addition to Eratosthenes, there was the astronomer Hipparchus who mapped the constellations and established the brightness of the stars.
00:42:46And there was Euclid who brilliantly systematized geometry.
00:42:52Who told his king, who was struggling with some difficult problem in mathematics, that there was no royal road to geometry.
00:43:02There was Dionysius of Thrace, the man who defined the parts of speech, nouns, verbs, and so on.
00:43:09Who did for language in a way what Euclid did for geometry.
00:43:13There was Herophilus, a physiologist who identified the brain rather than the heart as the seed of intelligence.
00:43:22There was Archimedes, the greatest mechanical genius until the time of Leonardo da Vinci.
00:43:27And there was the astronomer Ptolemy who compiled much of what today is the pseudo-science of astrology.
00:43:35His Earth-centered universe held sway for 1500 years.
00:43:40Showing that intellectual brilliance is no guarantee against being dead wrong.
00:43:46And among these great men, there was also a great woman.
00:43:51Her name was Hypatia.
00:43:53She was a mathematician and an astronomer.
00:43:56The last light of the library whose martyrdom is bound up with the destruction of this place seven centuries after it was founded.
00:44:23Look at this place.
00:44:28The Greek kings of Egypt who succeeded Alexander regarded advances in science, literature, and medicine as among the treasures of the empire.
00:44:37For centuries they generously supported research and scholarship.
00:44:42An enlightenment shared by few heads of state then or now.
00:44:46Off this great hall were ten large research laboratories.
00:45:00There were fountains and colonnades, botanical gardens, and even a zoo with animals from India and sub-Saharan Africa.
00:45:09There were dissecting rooms and an astronomical observatory.
00:45:16But the treasure of the library consecrated to the god Serapis built in the city of Alexander was its collection of books.
00:45:26The organizers of the library combed all the cultures and languages of the world for books.
00:45:32They sent agents abroad to buy up libraries.
00:45:35Commercial ships docking in Alexandria harbor were searched by the police.
00:45:41Not for contraband, but for books.
00:45:43The scrolls were borrowed, copied, and returned to their owners.
00:45:47Until studied, these scrolls were collected in great stacks called books from the ships.
00:45:55Accurate numbers are difficult to come by.
00:45:58But it seems that the library contained at its peak nearly one million scrolls.
00:46:17The papyrus reed grows in Egypt.
00:46:22It's the origin of our word for paper.
00:46:24And each of those million volumes which once existed in this library were handwritten on papyrus manuscript scrolls.
00:46:33What happened to all those books?
00:46:35Well, the classical civilization that created them disintegrated.
00:46:39The library itself was destroyed.
00:46:42Only a small fraction of the works survived.
00:46:45And as for the rest, we are left only with pathetic, scattered fragments.
00:46:50But how tantalizing those remaining bits and pieces are.
00:46:55For example, we know that there once existed here a book by the astronomer Aristarchus of Samos.
00:47:03Who apparently argued that the Earth was one of the planets.
00:47:08That like the other planets, it orbits the sun.
00:47:12And that the stars are enormously far away.
00:47:16All absolutely correct.
00:47:18But we had to wait nearly 2,000 years for these facts to be rediscovered.
00:47:24The astronomy stacks of the Alexandria Library.
00:47:37Hipparchus.
00:47:38Hipparchus.
00:47:39Hipparchus.
00:47:40Hipparchus.
00:47:41Hipparchus.
00:47:42Hipparchus.
00:47:43Hipparchus.
00:47:44Hipparchus.
00:47:45Hipparchus.
00:47:46Hipparchus.
00:47:52Hipparchus.
00:47:53This is the book.
00:47:54How I'd love to be able to read this book.
00:47:55To know how Aristarchus figured it out.
00:47:56But it's gone... utterly and forever.
00:47:59If we multiply our sense of loss for this work of Aristarchus by 100,000,
00:48:05we begin to appreciate the grandeur of the achievement of classical civilization
00:48:10and the tragedy of its destruction.
00:48:17We have far surpassed the science known to the ancient world,
00:48:22but there are irreparable gaps in our historical knowledge.
00:48:26Imagine what mysteries of the past could be solved with a borrower's card to this library.
00:48:32For example, we know of a three-volume history of the world,
00:48:37now lost, written by a Babylonian priest named Berossus.
00:48:42Volume one dealt with the interval from the creation of the world to the great flood,
00:48:47a period that he took to be 432,000 years,
00:48:51or about 100 times longer than the Old Testament chronology.
00:48:54What wonders were in the books of Berossus?
00:48:59But why have I brought you across 2,000 years to the library of Alexandria?
00:49:06Because this was when and where we humans first collected seriously and systematically
00:49:14the knowledge of the world.
00:49:17This is the Earth that Zeratosthenes knew it,
00:49:20a tiny spherical world afloat in an immense amount of space and time.
00:49:26We were, at long last, beginning to find our true bearings in the cosmos.
00:49:32The scientists of antiquity took the first and most important steps in that direction
00:49:38before their civilization fell apart.
00:49:42But after the Dark Ages, it was by and large the rediscovery of the works of these scholars
00:49:48done here that made the Renaissance possible and thereby powerfully influenced our own culture.
00:49:55When, in the 15th century, Europe was at last ready to awaken from its long sleep,
00:50:02it picked up some of the tools, the books, and the concepts laid down here more than 1,000 years before.
00:50:10By 1600, the long-forgotten ideas of Aristarchus had been rediscovered.
00:50:22Johannes Kepler constructed elaborate models to understand the motion and arrangement of the planets,
00:50:29the clockwork of the heavens.
00:50:35And at night, he dreamt of traveling to the moon.
00:50:40His principal scientific tools were the mathematics of the Alexandrian library
00:50:55and an unswerving respect for the facts, however disquieting they might be.
00:51:05His story and the story of the scientists who came after him
00:51:08are also part of our voyage.
00:51:13Seventy years later, the sun-centered universe of Aristarchus and Copernicus
00:51:18was widely accepted in the Europe of the Enlightenment.
00:51:22The idea arose that the planets were worlds
00:51:26governed by laws of nature
00:51:27and scientific speculation turned to the motions of the stars.
00:51:31The clockwork in the heavens was imitated by the watchmakers of Earth.
00:51:37Precise timekeeping permitted great sailing ship voyages
00:51:41of exploration and discovery, which bound up the Earth.
00:51:45This was a time when free inquiry was valued once again.
00:51:52Two hundred fifty years later, the Earth was all explored.
00:52:02New adventurers now looked to the planets and the stars.
00:52:06The galaxies were recognized as great aggregates of stars,
00:52:10island universes, millions of light-years away.
00:52:14In the 1920s, astronomers had begun to measure the speeds of distant galaxies.
00:52:26What time is it?
00:52:27Uh, 7.15.
00:52:29All right, lights off, please.
00:52:31They found that the galaxies were flying away from one another.
00:52:36To the astonishment of everyone, the entire universe was expanding.
00:52:47We had begun to plumb the true depths of time and space.
00:52:52The long collective enterprise of science
00:52:57has revealed a universe some 15 billion years old.
00:53:02The time since the explosive birth of the cosmos, the Big Bang.
00:53:13The cosmic calendar compresses the local history of the universe into a single year.
00:53:19If the universe began on January 1st,
00:53:22it was not until May that the Milky Way formed.
00:53:25Other planetary systems may have appeared in June, July, and August.
00:53:32But our sun on Earth, not until mid-September.
00:53:35Life arose soon after.
00:53:38Everything humans have ever done occurred in that bright speck
00:53:42at the lower right of the cosmic calendar.
00:53:48The Big Bang is at upper left in the first second of January 1st.
00:53:5315 billion years later is our present time, the last second of December 31st.
00:54:06Every month is one and a quarter billion years long.
00:54:09Each day represents 40 million years.
00:54:12Each second stands for some 500 years of our history.
00:54:16The blinking of an eye in the drama of cosmic time.
00:54:26At this scale, the cosmic calendar is the size of a football field,
00:54:31but all of human history would occupy an area the size of my hand.
00:54:35We're just beginning to trace the long and tortuous path which began with the primeval fireball
00:54:42and led to the condensation of matter.
00:54:45Gas, dust, stars, galaxies, and at least in our little nook of the universe,
00:54:50planets and life, intelligence, and inquisitive men and women.
00:54:54We've emerged so recently that the familiar events of our recorded history
00:54:59occupy only the last seconds of the last minute of December 31st.
00:55:04Some critical events for the human species, however, began much earlier, minutes earlier.
00:55:09So we change our scale from months to minutes.
00:55:15Down here, the first humans made their debut around 10.30 p.m. on December 31st.
00:55:25And with the passing of every cosmic minute, each minute 30,000 years long,
00:55:30we began the arduous journey towards understanding where we live and who we are.
00:55:3411.46, only 14 minutes ago, humans have tamed fire.
00:55:4611.59.20, the evening of the last day of the cosmic year,
00:55:52the eleventh hour, the 59th minute, the 20th second.
00:55:56The domestication of plants and animals begins.
00:55:59An application of the human talent...
00:56:04for making tools.
00:56:1311.59.35,
00:56:16settled agricultural communities evolve into the first cities.
00:56:21We humans appear on the cosmic calendar so recently
00:56:25that our recorded history occupies only the last few seconds of the last minute of December 31st.
00:56:34In the vast ocean of time which this calendar represents,
00:56:39all our memories are confined to this small square.
00:56:46every person we've ever heard of lived somewhere in there.
00:56:52All those kings and battles, migrations and inventions, wars and loves,
00:56:58everything in the history books happens here,
00:57:02in the last ten seconds of the cosmic calendar.
00:57:05We on earth have just awakened to the great oceans of space and time from which we have emerged.
00:57:19We are the legacy of 15 billion years of cosmic evolution.
00:57:25We have a choice.
00:57:28We can enhance life and come to know the universe that made us,
00:57:32or we can squander our 15 billion year heritage in meaningless self-destruction.
00:57:38What happens in the first second of the next cosmic year depends on what we do, here and now,
00:57:45with our intelligence and our knowledge of the cosmos.
00:58:15We are the one who is in the last minute.
00:58:19It's the same reason for years.
00:58:20What happens in the next six days?
00:58:21We have a choice, love with the stars,
00:58:22we have a choice.
00:58:25It's the same reason for us.
00:58:27It's the same reason for us.
00:58:30It's the same reason.
00:58:32The cells of the universe look like in the whole world.
00:58:36And that is the same reason for us.
00:58:38We have a choice.
00:58:40We have a choice.
00:58:42Now,