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00:00I
07:40Because we begin.
07:42A few light-years across, surrounding the Sun…
07:47ORT's logic still holds up
07:49even after all the discoveries we've made about comets in the solar system in the many decades since.
07:55And yet, the ORT cloud is a site that no one has ever seen.
08:01Nor could we.
08:02It's dark out here.
08:04And each comet is about as far from its closest neighbor as the Earth is from Saturn.
08:09But science gives us special powers of our own.
08:13It gave Yohan Ort the gift of prophecy.
08:16Ort was also the first to correctly estimate the distance between the sun and the center of our galaxy.
08:22That's a big deal, finding out where we are in the Milky Way.
08:27Our star is about 30,000 light years from the center.
08:31Ort was also the first guy to use a radio telescope to map the galaxy's spiral structure.
08:36And he discovered that the center of our galaxy was a place of titanic explosions.
08:43The first indication that there might have been a supermassive black hole lurking there.
08:48Does the fact that most of us know the names of mass murderers, but never heard of Yohan Ort, say anything about us?
08:54The Oort cloud is so enormous that it takes one of its comets about a million years to complete a single trip around the sun.
09:12Out here at the far edge of the solar system, even a little tug from the gravity of a passing star can liberate some of these comets from their gravitational bondage to the sun.
09:26Some comets are flung out of the solar system to wander interstellar space, but for others, there's a different fate.
09:37This one is plunging towards the sun, gaining speed in an unbroken freefall that lasts hundreds of thousands of years.
09:52When Neptune's gravity gives it another tug, there's a small change in course.
10:00Mighty Jupiter, the most massive object in our solar system, other than the sun, attracts the comet with its powerful gravitational pull, bending its path.
10:09When our comet reaches the inner solar system, heat from the sun bakes it.
10:30A beautiful transformation begins.
10:34The barren, sooty iceberg now sports a glowing halo.
10:39And a tail.
10:48These layers tell the story of how the comet was made some four billion years ago.
10:59During the 40,000 generations of humanity, there must have been roughly 100,000 apparitions of a bright comet.
11:06For all that time, the best we could do was look up in helpless wonder.
11:13Prisoners of Earth with nowhere to turn for an explanation beyond our guilt and our fears.
11:19But then a friendship began between two men that led to a permanent revolution in human thought.
11:29Isaac Newton and Edmund Halley could not know it, but their collaboration would ultimately set us free from our long confinement on this tiny world.
11:39The comet of 1664 sent shivers of dread throughout Europe, and the terror seemed justified when the plague and the great fire of London followed soon after.
11:55There with long bloody hair, a blazing star threatens the world with famine, plague, and war.
12:07To princes it spells death, to kingdoms many crosses, to all estates inevitable losses, to herdsmen rot, to plowmen hapless seasons,
12:26to sailors it brings storms, to cities civil treasons.
12:35But for one child, the comet was not the least bit frightening.
12:45For him, it was a thing of wonder.
12:56Like all of us, Edmund Halley was born curious.
13:00He was lucky to have a father who encouraged and nurtured his curiosity, buying him the best scientific instruments,
13:09and even funding his expedition to make the first accurate star map of the southern hemisphere.
13:15Halley dropped out of Oxford when he was 20 and sailed to St. Helena,
13:19an island below the equator off the west coast of Africa.
13:29How's it, how's it?
13:31Problem was, nobody told Halley that the weather on St. Helena was generally lousy.
13:36It took him 12 frustrating months to observe enough southern stars to make a complete map.
13:43The gods and heroes of ancient Greece were now joined by the mythic figures of a new world and age.
13:50A toucan, a compass, a bird of paradise.
13:54When Halley came home with the other half of the sky, his map created a sensation.
14:08Now merchants and explorers could navigate by the stars visible anywhere on Earth.
14:13At the time, the Royal Society of London was the world's clearinghouse of scientific discovery.
14:18Its motto, Nullius in Verba.
14:21It sums up the heart of the scientific method.
14:24It's Latin for see for yourself.
14:27In other words, question authority.
14:30Halley's star maps caught the attention of the society's curator of experiments.
14:34I'd show them to you if I could, but no portrait of Robert Hooke exists from his time.
14:39Only the verbal descriptions of his contemporaries.
14:42They called him mean, bent, ugly.
14:45He was possibly the most inventive person who ever lived.
14:48And despite his appearance, he was the most sought after party guest in all of London.
14:53Why?
14:54Hooke's insatiable curiosity encompassed absolutely everything.
14:59Hooke discovered a little cosmos.
15:04And we still call it by the name he gave it.
15:07The cell.
15:08Hooke discovered the cell by looking at a piece of quark with one of his own inventions.
15:13The compound microscope.
15:15He anticipated aspects of Darwin's theory of evolution by almost 200 years.
15:20Hooke also improved the telescope.
15:23The drawings he made of the astronomical bodies he observed attest to his uncanny precision.
15:28After the great fire destroyed central London in 1666, Hooke partnered with the architect Christopher Wren to redesign and rebuild the city.
15:38Hooke was the foremost experimentalist of his age.
15:42Using coiled springs, he derived the law of elasticity, known today as Hooke's law.
15:49He perfected the air pump, the height of technology in its time, and used it to experiment on respiration and sound.
15:57And he experimented with cannabis.
16:00He reported to a meeting of the Royal Society that a sea captain friend of his, quote,
16:05had so often experimented with it, that there is no cause of fear, though possibly there may be of laughter.
16:17But coffee was the drug of choice for England in the 17th century.
16:21Coffee houses sprang up all over London.
16:36This is where people came to get news, to launch new ventures, and to debate ideas.
16:42The coffee house was an oasis of equality in a class-obsessed society.
16:48Here, a poor man needn't give up his seat to a rich man, nor submit to his opinion.
16:53It was a kind of laboratory of democracy.
16:56In this highly caffeinated atmosphere, Halley and Hooke met Christopher Wren to discuss a deep mystery.
17:03Why do the planets move as they do?
17:06The astronomer Johannes Kepler had demonstrated, some 80 years before,
17:10that the orbits of the planets around the sun were not perfect circles, but actually ellipses.
17:16And that the closer a planet was to the sun, the faster it moved.
17:21Why? Could some invisible force from the sun be responsible for this change in motion?
17:29If so, how did it work?
17:31Could there be a simple mathematical law to describe it?
17:34Maybe something like Hooke's Law of Elasticity?
17:42Perhaps, but try as he might, Christopher Wren couldn't figure it out.
17:47Damned if I haven't tried. It's beyond me.
17:50I'll wager a book worth 40 shillings to the man who can solve it.
17:54That book is mine, Mr. Wren. I've already done the calculation.
17:58Halley was delighted.
17:59Show us, Mr. Hooke.
18:01But months passed, and Hooke failed to deliver.
18:04He couldn't do the math. None of them could.
18:07Finally, Halley had enough of Hooke's excuses.
18:10Halley knew there must be someone, somewhere up to the challenge.
18:20What about that mathematician at Cambridge?
18:24He was a clever fellow.
18:26He had solved central questions about the nature of light years before,
18:30when he was still only 22.
18:32And he invented the reflecting telescope.
18:35Odd bird.
18:36Dropped out of sight a while back.
18:38Some squabble over Hooke and his discovery about light.
18:41Went completely to pieces over it that's been hiding out in Cambridge ever since.
18:45Halley wondered if this strange and, by all accounts, exceedingly difficult man
18:50might succeed where Hooke and others had failed.
18:53What he couldn't know, what no one could possibly imagine at the time,
18:57were the countless ways the world would be forever changed
19:00by this meeting on an August day in 1684.
19:04Isaac Newton was born in England on Christmas day in 1642.
19:17Before he even opened his eyes, his father was already dead.
19:23His mother left him when he was only three and did not return until he was 11.
19:29When she did, it was with a new family and husband,
19:33a stepfather who Isaac Newton despised.
19:41Newton's refuge from his miserable family life
19:44was his passion to understand how things worked,
19:48especially nature itself.
19:51In 1661, the talented young Isaac entered Trinity College at Cambridge University,
19:56where he was a consistently lousy student.
20:00One without friends or a loving family to provide any warmth or encouragement.
20:05Newton mostly kept to himself, sequestered in his room,
20:09studying ancient Greek philosophers, geometry, and languages,
20:13and pondering deep questions on the nature of matter, space, time, and motion.
20:19This budding scientist was also a passionate mystic.
20:24Newton believed that a secret knowledge called alchemy,
20:28known only to a small group of ancient philosophers,
20:31was waiting to be rediscovered.
20:33He hoped to learn how to change ordinary metals into silver and gold,
20:38and maybe even cook up the elixir of life, the key to immortality.
20:43He was also obsessed with finding hidden messages in the words of the Bible.
20:51He combed through translations in several different languages,
20:55hoping to decipher coded instructions from God.
20:58He made elaborate calculations in an effort to discover the date of the Second Coming.
21:11His lifelong research at alchemy and biblical chronology never led anywhere.
21:17When Halley found Newton that fateful day, he was living as a virtual recluse.
21:31Newton had gone into hiding 13 years earlier,
21:34after Robert Hooke had publicly accused Newton
21:37of stealing his groundbreaking work on light and color.
21:40In fact, it was Isaac Newton who solved the mystery of the spectrum of light,
21:45not Robert Hooke.
21:47The wound was painful and deep,
21:49and Newton resolved to never expose himself
21:52to that kind of public humiliation ever again.
21:55Sir, I don't suppose you recall our meeting a few years ago?
21:59Yes, Mr. Halley?
22:01I'm sorry to bother you.
22:03Never mind the formalities. Get to your point.
22:05I've been talking with our friends, Mr. Wren and Mr. Hooke.
22:09That scoundrel Hooke's no friend of mine.
22:12Yes, I understand, sir.
22:14But the thing is, we've been debating
22:16the puzzling question of planetary motion.
22:19We all agree that some force of attraction from the sun
22:22governs the motions of the planets.
22:24We suspect there must be a mathematical law
22:27to describe how this force changes with distance.
22:30And knowing of your skill...
22:32Yes, yes, the attraction of gravity
22:34weakens with the square of the distance.
22:36That's why the planets move in ellipses.
22:38But, sir, how can you know this?
22:41Why, I have calculated it some five years ago.
22:44I beg you, show it to me.
22:47The calculation is here. Somewhere.
22:50Well, no matter. I shall redo it and be sure to send it on to you.
22:54This is stupendous. Why have we not had word of it before?
22:59Newton remembered all too well what Hooke had done to him
23:02the last time he put forth an idea.
23:06Just when Halley may have begun to wonder if Newton was bluffing,
23:09as Hooke had done earlier,
23:11a messenger arrived with an envelope from Newton.
23:14Here are the opening pages of modern science.
23:23With its all-embracing vision of nature,
23:25universal laws of motion, gravity.
23:29Not just for the Earth, for the cosmos.
23:34Halley raced back to Cambridge.
23:36Mr. Newton, I beseech you to work all of this into a book
23:40as soon as possible.
23:41I can assure you, the Royal Society will publish it.
23:45But there was one little problem.
23:48We are in agreement that Mr. Newton has produced a masterpiece.
23:53However, I'm afraid the Royal Society has, well,
23:57regrettably, sales for the history of fish
24:00have not lived up to our financial expectations.
24:05It's an impressive book.
24:07Extremely comprehensive.
24:09Really.
24:11It's filled with lavish illustrations of, well, fish.
24:18The disappointing sales led to a bigger problem.
24:21The Royal Society pretty much blew its total annual budget
24:24on the history of fish.
24:26In fact, they were so strapped for cash,
24:29they had to pay poor Halley's salary
24:31with copies of their worst-selling book.
24:34With no money to print Newton's Principia,
24:37the scientific revolution hung in the balance.
24:42Without Halley's heroic efforts,
24:44the reclusive Newton's masterwork
24:46might never have seen the light of day.
24:49But Halley was a man on a mission,
24:51absolutely determined to bring Newton's genius to the world.
24:55That pre-scientific world,
24:57the world ruled by fear,
25:00was poised at the edge of a revolution.
25:03Everything depended on whether or not
25:05Edmund Halley could get Newton's book out to the wider world.
25:09Halley resolved not only to edit Newton's book,
25:12but to publish it at his own expense.
25:15Newton completed the first two volumes,
25:18laying the mathematical framework of the physics of motion.
25:21The third volume would settle once and for all who won the coffeehouse wager.
25:27Newton applied his principles to explain all the known motions of the earth,
25:31the moon, and the planets.
25:34Unfortunately, it was this problem.
25:37Now Halley also took on the role of Newton's psychotherapist.
25:41Isaac, I'm afraid that Mr. Hook requires an acknowledgement in the preface of your third volume.
25:48But I have done so, thanking him, Mr. Wren, and yourself for prodding me to think again on astronomical matters.
25:54Mr. Hook has been going about London, saying that you got the law of gravity from him.
26:01Why, that litigious little...
26:03Never! I would sooner burn the third volume than deface it with such a lie.
26:08To hell with Hook. He will be long forgotten when your ideas are still being celebrated.
26:12More copies of that dreadful book!
26:18Wherever shall we put them all?
26:21We talked about this, Mary dear.
26:23This is my salary from the society.
26:26They have nothing else with which to pay me.
26:28If only Mr. Hook and Mr. Newton were more like you.
26:33Halley and Wren decided to confront Hook about his false claims.
26:37That law is mine, I tell you!
26:38I proved it first!
26:40Then fetch your proof here at once.
26:42Let us see it.
26:43Surely we have waited on it long enough.
26:47You'll simply have to take my word for it.
26:50Empty claims may persuade elsewhere, but not here.
26:54Put up or shut up, Mr. Hook.
26:58Exhausted, Newton. How many can pay you?
27:08If it wasn't for Edmund Halley, Newton's great book would have never been conceived, nor written, nor printed.
27:24Okay, so what? What difference does that make to us?
27:29It's the big deal.
27:30When Isaac Newton was born in this house in 1642, the world was very different.
27:44Everyone looked at the perfection of the clockwork motions of the planets in the sky,
27:48and could only understand it as the work of a master clockmaker.
27:52How else to explain it?
27:54There was only one way such a thing could come about in their imagination.
27:58Only one answer for them.
28:00God.
28:02For reasons beyond our understanding, God just created the solar system that way.
28:07But this explanation is the closing of a door.
28:10It doesn't lead to other questions.
28:11Along came Newton, a God-loving man who was also a genius.
28:28He could write the laws of nature in perfect mathematical sentences.
28:33Formulas that applied universally to apples, moons, planets, and so much more.
28:42With one foot still in the Middle Ages,
28:45Isaac Newton imagined the whole solar system.
28:48Newton's laws of gravity and motion revealed how the sun held distant worlds captive.
28:54His laws swept away the need for a master clockmaker to explain the precision and beauty of the solar system.
29:02Gravity is the clockmaker.
29:05Matter obeyed commandments we could discover, laws the Bible hadn't mentioned.
29:11Newton's answer to why the solar system is the way it is opened the way to an infinite number of questions.
29:18Principia also happened to include the invention of calculus and the first sound theoretical basis for an end to our imprisonment on Earth.
29:27Space travel.
29:28Newton envisioned the firing of a cannonball with increasingly greater explosive thrust.
29:39He reasoned that with enough velocity the bounds of gravity could be broken and the cannonball could escape to orbit the Earth.
29:50This changed everything.
29:52This changed everything.
29:54node
29:56Episode 6
29:57Station
30:53Newton's Principia Mathematica set us free in another way.
31:02By finding the natural laws governing the comings and goings of comets,
31:06he decoupled the motions of the heavens from their ancient connections to our fears.
31:14If Halley hadn't been standing next to Newton for all those years,
31:18perhaps the world would remember him for his own host of accomplishments and discoveries.
31:23But the only thing that comes to mind for most people is the comet.
31:28The irony is that discovering a comet is actually one of the few things that Halley never did.
31:34What a noise to start it!
31:42Come about!
31:45After the publication of the Principia, Halley was commanded by his king to lead three ocean voyages,
31:54scientific expeditions to solve navigational problems for the British Navy.
31:58Halley used this opportunity to make the first map of the Earth's magnetic field.
32:08And he was also a businessman.
32:13Halley perfected the diving bell
32:15and used his invention to start a flourishing commercial salvage operation.
32:27My doctor, Halley's gone and done it his time.
32:29I reckon he's been down there at least three hours.
32:31Not one to risk the lives of others.
32:35Halley personally tested his own invention.
32:42I make it exactly four hours since our descent.
32:46Not at all bad for ten fathoms.
32:47He invented the weatherman.
32:57And the symbols he devised for indicating prevailing winds are still in use today.
33:03Halley laid the groundwork for the science of population statistics.
33:18How?
33:20He compared the birth, marriage, death, and population densities of London and Paris.
33:25He actually had to pace off the entire perimeter of Paris on foot to learn its true dimensions.
33:30He came to the conclusion that since roughly half of all adults fail to reproduce children,
33:36who themselves survive to reproduce,
33:38every married couple must have four children in order to maintain the population.
33:46And it was Edmund Halley who gave us the actual scale of the solar system.
33:50He figured out a clever way to find the distance from Earth to the Sun.
33:54It involved precisely measuring the time it took for the planet Venus to cross the Sun's disk.
34:0027 years after Halley's death,
34:06Captain James Cook made his first voyage to Tahiti
34:08for the express purpose of testing Halley's method
34:11during a transit of Venus across the Sun.
34:15Using a special filter to protect his vision from being destroyed by looking directly at the Sun,
34:20Cook and his men made it possible for us to know
34:22that the Sun is 93 million miles from Earth.
34:26And Halley was the first to realize that the so-called fixed stars were not fixed at all.
34:34How'd he do it?
34:35He poured over the observations made by the ancient Greek astronomers of the brightest stars.
34:40He compared their observations with the ones he himself made of the same stars 1800 years later.
34:46Why had anyone noticed this before?
34:50Halley figured out that it was only become apparent if you waited long enough between observations.
34:56It's hard to perceive the motions of things that are far away.
35:00And the stars are so very far away that you would need to track them for many centuries
35:04before you could detect that they moved at all.
35:07Halley discovered the first clue to a magnificent reality.
35:14All the stars are in motion, streaming past each other,
35:18rising and falling like merry-go-round horses in their Newtonian dance
35:22around the center of our galaxy.
35:26And, oh yes, it was that thing about the comet.
35:29What were those strange and beautiful celestial visitors
35:38that appeared without warning from time to time?
35:41Halley set out to solve this mystery as a detective would
35:43by gathering all credible eyewitness testimony.
35:47The earliest precise observations of a comet that Halley could find
35:50were made in Constantinople by Nycophorus Gregoris,
35:55a Byzantine astronomer and monk, in June 1337.
35:58Halley hunted down every astronomical observation of a comet
36:03recorded in Europe between 1472 and 1698.
36:09And remember, there was no such thing as a search engine or a computer.
36:13All Halley had were his books and his mind.
36:17Now here comes the hard part.
36:18Halley had to take the observations made for each comet
36:21and find the shape of its actual path through space.
36:24No one else but Newton had yet attempted to apply his new set of laws
36:29to an astronomical question.
36:31In an arduous tour de force of mathematical brilliance,
36:34Halley discovered that comets were bound to the sun
36:37in long elliptical orbits.
36:39And he was the first to know that the comets seen in 1531,
36:501607,
36:52and 1682
36:53were one and the same.
36:57A single comet that returned every 76 years.
37:00And a stunning example of true pattern recognition.
37:03He predicted it would be seen again more than 50 years in the future.
37:10For millennia, comets have been props for mystics
37:13who considered them to be merely omens of human events.
37:18Halley shattered their monopoly,
37:20beating them at their own game.
37:22A game that no scientist had ever played before.
37:27Prophecy.
37:27And he did not hedge his bed.
37:30Like Babe Ruth predicting where his next home run
37:32would land in the stands,
37:34Halley stated flatly
37:35that the comet would return at the end of 1758
37:39from a particular part of the sky
37:41following a specific path.
37:45There is hardly a prophecy attempted by the mystics
37:47that ever even strives for comparable precision.
37:50That's Halley's comet.
38:11Out here at the edge of the solar system
38:13doesn't look like much.
38:14Just a big hunk of ice and rock in space.
38:18That's because beyond the orbit of Neptune,
38:19nearly 5 billion kilometers from the sun,
38:23comets lead very quiet lives.
38:27As it reaches the far end of its orbit,
38:30it'll slow down
38:31till the sun allows it to go no farther.
38:33Then it'll begin its long fall
38:36back to the inner solar system.
38:39Halley's comet is in free fall around the sun.
38:42Everything in our solar system,
38:44the Earth, the Moon, the other planets,
38:46comets, asteroids,
38:47all of them are falling around the sun.
38:50Gravity pulls the planets towards the sun,
38:53but because of their orbital momentum,
38:55they keep moving around the sun,
38:58never falling into it.
38:59Robert Hooke had died years before,
39:06having ruined his health with some bad habits.
39:09Daily doses of wormwood, opium, mercury.
39:13A few months later,
39:14Newton was elected to replace him
39:16as president of the Royal Society.
39:18It is said that a portrait of Hooke
39:20once hung on these walls.
39:24Halley lived on to accomplish
39:25many more astonishing feats.
39:28He worked right up to his death
39:29at age 85.
39:32His final act
39:34was to call for a glass of wine.
39:36He downed it with pleasure
39:38and breathed his last breath.
39:46Some believed
39:47that it was on a night like this
39:49that Isaac Newton
39:51finally took his revenge
39:52against Robert Hooke.
40:09But Halley's prophecy
40:10was not forgotten.
40:12Fifty years later,
40:14as the time of the predicted return approached,
40:16the world's astronomers vied
40:18to be the first
40:19to catch sight of his comet.
40:21They weren't disappointed.
40:23It's been welcomed back
40:24every 76 years since.
40:27When Halley's Comet returns to our skies,
40:30sunlight will warm up the ice
40:32on its surface,
40:33once again setting loose
40:34the dust and gases trapped within.
40:40Halley's Comet most recently
40:42visited our neighborhood
40:43back in 1986.
40:46And if you're seeing this
40:47in 2061,
40:49then you'll know it's back.
40:53May you feel the wonder
40:55of all those
40:56who came before you
40:57and none of the fear.
41:01Newton's laws
41:02made it possible
41:03for Edmund Halley
41:04to see some 50 years
41:05into the future
41:06and predict the behavior
41:08of a single comet.
41:10Scientists have been using
41:11these laws ever since,
41:14opening the way to the moon
41:15and even beyond
41:16our solar system.
41:18The baby in the basket
41:20is learning to walk.
41:21and to know
41:29the cosmos.
41:34Which brings me to
41:36one last prophecy.
41:38Using nothing more than
41:39Newton's laws of gravitation,
41:41we astronomers
41:42can confidently predict
41:43that several billion years
41:45from now,
41:46our home galaxy,
41:48the Milky Way,
41:49will merge with our
41:50neighboring galaxy,
41:52Androma.
41:54Because the distances
41:55between the stars
41:56are so great
41:57compared to their sizes,
41:59few, if any, stars
42:00in either galaxy
42:01will actually collide.
42:02Any life on the worlds
42:05of that far-off future
42:06should be safe,
42:07but they would be treated
42:08to an amazing
42:09billion-year-long
42:11light show.
42:13A dance
42:15of a half a trillion stars
42:17to music
42:19first heard
42:20on one little world
42:21by a man
42:23who had
42:23but one true friend.
42:25is not zag
42:39oo
42:40were
42:48are
42:50are
42:51are
42:51are
42:52are
42:54are