"STEPHEN HAWKING'S UNIVERSE" "BLACK HOLES AND BEYOND" ""Stephen Hawking's Universe" is made possible... by Alfred P. Sloan foundation to enhance public understanding... of the role of science and technology." "The Arthur Vining Davis foundations." "The corporation for public broadcasting." "And viewers like you." "Corporate funding is provided by Amgen." "Unlocking the secrets of life through biotechnology." "At Amgen, we produce medicines... that improve people's lives today... and bring hope for tomorrow." "Hawking:" "The farther we probe into the universe," "The more remarkable are the discoveries we make." "Much of my work has been concerned" "With the mysteries of black holes." "Many people dismiss black holes" "As just an artifact of the theory," "Which wouldn't exist in the real world." "But then observers began to find things in the sky" "Which were just as peculiar." "Narrator:" "In the end, scientists would find" "Some very peculiar things..." "Impossibly bright objects blazing from the distant past," "And forces of impenetrable darkness." "The first thing they found was signals," "Radio waves from space." "Astronomers tuned in in search of aliens." "Man:" "Well, my name is seth shostak," "And i'm a an astronomer at the seti institute" "Here in lovely mountain view, california." "The acronym "seti" stands for" "Search for extra-Terrestrial intelligence." "Now, that "i" on the end" "Means we're not looking for extraterrestrial life," "But we're looking for intelligent life." "That means they can hold up their side of the conversation," "If you will." "After the second world war," "Radio astronomy really got going." "And in the late '50s," "They started building large radio telescopes," "Like the one we're sitting underneath." "Could this technology" "Actually be used to send messages, as it were," "Between the stars?" "In 1959, 1960, the first experiments were made" "Using this kind of technology..." "a big radio telescope..." "To try and eavesdrop on any civilizations" "That might be nearby." "Narrator:" "No aliens found, granted," "But there was no mistaking the signals." "Shostak:" "Suddenly, you were getting" "These clear radio views, so you knew that" "In that direction" "There's a very strong source of radio waves." "You would tell your friend the optical astronomer," "And they would go use a big telescope," "Like the palomar 200-Inch telescope," "Or something similar," "And they would point it in that direction." "Narrator:" "Where the universe emitted a radio signal," "Optical astronomers now trained their gaze." "What they saw defied explanation." "But at first, its significance eluded them." "Man:" "People saw that they were unusual objects." "For example, a galaxy that had a peculiar blob within it" "In some cases was found to emit radio waves." "Whereas a normal-Looking, boring-Looking galaxy did not." "Or, for example," "A cloud of gas that had" "All sorts of little striations in it," "And looked as though it might be exploding..." "Those were precisely the objects" "That seemed to emit radio waves." "Whereas more normal, quiescent clouds of gas did not." "Narrator:" "Gradually, the strange evidence mounted." "When observers turned their telescopes" "On the source of particularly strong radio signals," "They expected to see cosmological catastrophes." "Instead, they were left with cosmic questions." "Filippenko:" "In the early 1960s," "Optical astronomers took photographs" "Of ctain positions in the sky" "From which radio waves seemed to be coming," "And they just saw nothing unusual." "There was just the usual smattering of stars," "And there was no obviously exploding star," "No turbulent cloud of gas, nothing seemingly unusual..." "Just normal stars." "And this perplexed the astronomers." "Narrator:" "Take the case of 3c273," "A star of no particular distinction." "It hardly seemed worth notice," "That is, until observers began to look a little closer." "Filippenko: 3c273 in the constellation virgo" "Looked just like a star," "Yet we know that ordinary stars don't emit radio waves," "And so this was highly, highly unusual." "Narrator:" "Using a technique called spectroscopy," "Astronomers studied the light" "Emitted by 3c273." "When you take a spectrum of an ordinary star," "That is when you pass the light through a prism" "And break it up into a rainbow," "You can see small dips, small wiggles in the spectrum." "And those are the wiggles that are produced by atoms," "By gases in the atmosphere of those stars" "That are absorbing some of the light." "And by identifying the pattern of these lines," "These little wiggles that appear in a star," "You can deduce whether the atmosphere of the star" "Has hydrogen or helium and oxygen..." "Things like that." "But if that pattern is shifted toward redder colors," "Then you deduce not only that the star has hydrogen" "Or other common elements," "But also that the star is moving away from you." "Hawking:" "34 years earlier," "The american astronomer, edwin hubble," "Had used spectroscopy to discover that" "The universe is expanding." "Distant galaxies are moving away from us." "The spectrum of 3c273 was about to tell us even more." "Filippenko:" "The spectrum of 3c273" "Didn't fit any patterns of normal gases" "That have been observed in normal stars." "And so this really befuddled astronomers." "Not only was the object emitting radio waves profusely," "But it had this really strange spectrum" "That couldn't be matched with any known type of gas." "Narrator:" "A star's spectrum is its signature," "And this one was an aberration." "It was enough to leave many astronomers confounded." "But for one, 3c273 was a revelation." "He was convinced spectroscopy couldn't lie." "Filippenko:" "Martin schmidt at caltech." "Noticed that two of the wiggles" "Had the same spacing between the colors" "As hydrogen does, but both of the lines" "Were shifted way over toward redder parts of the spectrum" "Than normal hydrogen gas is." "And if he believed that that identification was correct," "Then the conclusion was that the shift is a full 16%." "Yet a shift of 16% meant that this object" "Was moving away from us enormously fast, and had to be" "One or two billion light years away." "So, no way could it be a normal star" "Or even a peculiar magnetic star in our own galaxy." "It had to be some sort of a strange object" "That looks stellar or quasi-Stellar" "Simply because it's so, so far away," "And yet it's enormously bright." "So this really caught people by surprise," "And a few people, i think, had a hard time believing" "That anything so relatively bright" "Could be so far away." "Astronomers decided to call these objects," "These radio-Stars," "Quasi-Stellar radio sources." "They were clearly radio sources..." "They were discovered with radio telescopes..." "And they looked star-Like," "And hence the stellar aspect of the term." "So "quasi-Stellar radio sources" got contracted to "quasars."" "Martin schmidt concluded that it must be, intrinsically," "An extremely powerful source..." "An exceedingly bright object intrinsically..." "Because to appear as bright as it does in the sky," "Yet be so far away," "It has to put out a tremendous amount of energy per second..." "Much, much more than our sun..." "In fact, 100 to 1,000 times more" "Than our entire milky way galaxy of stars." "And this was the real kicker." "Hawking:" "When the mysterious quasars were discovered," "I was just beginning my post-Graduate research." "My work was to lead me to study things" "Even more mysterious..." "Black holes." "I was dealing with Einstein's general theory of relativity," "And this seemed, to some physicists," "A promising place to look" "For an explanation of the quasars." "Astronomers and astrophysicists wanted an explanation" "For how these strange objects" "Could behave in this extraordinary way..." "How they could produce so much energy," "And yet be so small." "And so they turned to the general relativists," "And asked them," ""Well, do you have any models for objects" ""That could look like this," "That could behave in this way at all?"" "And the relativists said," ""Well, there is this issue of gravitational collapse," "And maybe this is what you're looking for."" "Narrator:" "Gravity is the dominant force" "In the universe." "This tenet of Einstein's was irrefutable." "But there was no such consensus about what would happen" "Under violent conditions, like the death of a large star." "Einstein wondered, could its gravitational collapse" "Crush its vast quantities of matter" "Into the tiniest of points?" "Dowker:" "In 1939, two papers appeared." "One was by Einstein himself," "And one was by the american physicist," "Robert oppenheimer, and his co-Worker, snyder." "They discussed what would happen" "When a large amount of matter" "Was concentrated in a small region." "Narrator:" "Einstein rejected" "The prospect of infinite collapse." "But oppenheimer and snyder's calculations" "Made the conceptual leap." "Dowker:" "Using the rules of general relativity," "They predicted that that massive object" "Would undergo catastrophic gravitational collapse" "And would reach a critical radius" "At which it seemingly cuts itself off" "From the rest of the universe." "Narrator:" "For many, the idea of a star" "Descending into such an abyss was unthinkable..." "All the more so when the view was shared" "By the greatest living scientist." "Dowker:" "Einstein was convinced" "That you could never get to this critical radius," "That this critical radius was an impossibility in nature." "Narrator:" "The controversy was short-Lived for now." "With the second world war," "Oppenheimer's talents were needed elsewhere," "Developing the atomic bomb." "His earlier work languished, dismissed by peers" "As a radical departure from Einstein." "But oppenheimer had convinced one colleague," "John Wheeler." "Stick up for something." "And i think that's a wonderful way of saying" "What science is all about." "Stick up for something." "Man:" "I'm daniel holz, i'm a graduate student" "At the university of chicago," "And i'm going to see John Wheeler," "Who was my undergraduate adviser here at princeton." "Narrator:" "For holz," "These periodic visits with his mentor are a privilege." "At age 85, John Wheeler is still a luminary" "Of 20th century science." "Holz:" "He's certainly one of the greatest physicists alive," "And he's contributed in important ways" "In many different aspects of physics." "He's had fresh ideas" "That have pushed the very edges of our knowledge." "He loves to just sink his teeth into problems." "Part of his approach in physics is," "Find the biggest, most confusing thing he can," "And then go at it full steam and try to make sense of it." "Narrator:" "Wheeler was witness to a remarkable chapter" "In the annals of physics." "He worked with oppenheimer on the atomic bomb." "But before that," "When wheeler arrived at princeton" "In the 1940s," "Einstein was the most eminent member of the faculty." "In 1963, the controversy about collapsing stars" "Was rekindled by the discovery of quasars." "Wheeler had a difficult choice between two convictions" "And two cherished colleagues." "Though he differed with Einstein," "He recalls him fondly." "Wheeler:" "He was kind enough to invite me" "To bring my graduate students around to his house" "One day for tea." "One of those students, joe callaway, said," ""Professor Einstein," "When you're no longer living, what will happen to this house?"" "And Einstein's face was a study..." "Deep wrinkles, a wonderful smile and laugh," "And his beautiful voice" "With a bit of a german accent, but in clear english..." ""This house will never become a place of pilgrimage" "Where the pilgrims come to look at the bones of the saint."" "And so it is." "Narrator:" "Wheeler was never one to shy away from controversy." "To him, the notion of extreme gravitational collapse" "Was the stuff of inspiration." "And at oppenheimer's bidding, he took up the cause." "In fact, the idea was predicted" "By the laws of general relativity." "But to Einstein, in this case," "There was just so far his own theory could go" "Before it defied reality." "Wheeler:" "He seemed to have a psychological block" "Against considering collapse." "I don't know why." "Narrator:" "The truth is, even earlier theorists" "Had no such misgivings." "As early as the 18th century," "The mathematician pierre laplace pondered the possibility." "Oppenheimer went on to calculate the mathematics," "But wheeler coined the name." "Wheeler:" "After i'd used that phrase," ""Gravitationally completely collapsed object,"" "Several times," "I realized that it was just too long-Winded," "And i switched to "black hole."" "Narrator:" "The name stuck." "A black hole, by definition," "Is a place where gravity is so great," "It engulfs everything around it." "Holz:" "The key feature of a black hole" "Is that it's black," "That no light escapes from this region." "So what happens is you have this object" "That's getting dense, say, a star that's collapsing," "And it gets more and more compressed." "As it does that, objects close to the star" "Have a harder and harder time getting away." "In some sense," "The gravitational pull is stronger and stronger." "If you keep on extrapolating that," "The object gets more and more dense." "At some point, you reach the stage" "Where even light can't escape," "And if we we're standing far away from this star," "The light cannot get from the surface of the star to us." "At the point where that is reached," "You have a black hole." "Wheeler:" "Our russian friends had a different word," "And the french thought it sounded obscene," "But finally they were won around and they accepted it." "So a lot of people decided that the whole idea" "Of a black hole was patently ludicrous," "And that they couldn't exist." "In fact, Einstein was in this camp" "And did not see black holes as real physical objects." "The idea was something in nature" "Would prevent a black hole from forming..." "As you tried to put all this mass in one place," "Some mysterious force would come out" "And always prevent you" "From actually getting that much mass" "That you would actually end up collapsing to a black hole." "Hawking:" "I believed that black holes should exist," "But many physicists thought" "That was taking general relativity too far." "Narrator:" "Wheeler had another agenda" "In embracing the unlikely premise of black holes." "Quasars had become a nagging mystery." "Could it be, he wondered, that one phenomenon" "Could somehow explain the other?" "Holz:" "Wheeler, always being at the forefront," "Saw that these black holes were a windfall" "For explaining all sorts of astrophysical observations," "And would become very important" "In our understanding of the world." "And so he was egging everyone, urging everyone on" "To join in exploring this vista that opened up" "This landscape of science." "What can we do with these black holes?" "What are the implications for them?" "How will this affect the way we look at our universe?" "Hawking:" "Many of us were beginning to think" "There might be large numbers of black holes in the universe." "But that depended on what happened" "In the giant explosions" "That occur at the end of the life of massive stars." "Narrator:" "In the scrublands of central california" "Is a facility where scientists produced" "Some of the most important weapons of our time." "Even today, it is a compound shrouded in secrecy." "The lawrence livermore national laboratory" "Still buzzes with important scientific work." "But some of its technology, outdated now after the cold war," "Lies idle, awaiting the day" "It will be scrapped or carted away." "Among its guarded prizes is a powerful tool" "The defense department helped create," "The first supercomputer." "Its purpose..." "To help make the elaborate calculations" "Needed for nuclear weapons." "Dick white was one of the first scientists to use it." "White:" "I came here in 1956." "We were one of two national laboratories" "Charged with developing nuclear weapons" "For the united states." "The laboratory here at livermore," "And los alamos laboratory," "Had a virtual monopoly on computers." "The computers were designed for us." "So for a period of 20 years," "The development of computers" "Depended on the existence of these labs." "It opened up to us" "The possibility of calculating things" "That we could not even think of doing before." "Narrator:" "At first," "White needed the computer's power" "To test each new generation of the bomb." "But by the early '60s, the work was largely done," "So white and his colleagues" "Aimed their computer at a new problem," "Black holes." "Many theorists still didn't believe in them." "They envisioned a very different outcome" "For a large star." "A massive supernova" "Would blast it into oblivion." "White:" "The theory that they put forward" "Was that the core of the star," "The iron core, would collapse." "They believed that this collapse" "Would cause thermonuclear reactions" "That would blow up the star." "We set out believing in this model." "Sure enough it collapsed." "We had no doubt it was going to do that," "But it didn't follow their script." "What it did was to" "Instead, just continue on collapsing," "And never came to rest" "As the pressure built up." "Narrator:" "White confirmed" "That a large dying star would continue collapsing" "And end up as a black hole." "It seems wheeler and oppenheimer had been right." "White:" "We had been led by the computer calculations" "To results that we had not anticipated," "And that was an extraordinary time for me." "There was a lot of excitement about this result." "The people that worked in general relativity" "Were quite excited, because in a way, it said," "Well, the things that they had been" "Talking about for years..." "Very supermassive condensed stars" "With big gravitational fields..." "may indeed exist." "This is a plot of the velocity" "Of the in-Falling material in a star that has collapsed" "And beginning to form a black hole." "At this point, where the most rapidly in-Falling material is," "The velocity is about 99% the velocity of light." "Hawking:" "Computer calculations" "Showed that at least some explosions of stars" "Would form black holes." "But if nothing can get out of a black hole," "How could we detect one?" "Narrator:" "Sighting the unseeable wasn't going to be easy." "Except, that is, for a select breed of thinker," "Science fiction writers." "Black holes were just too hot an idea to pass up." "Man:" "Toby got it now." ""The black hole?" "It's pulling the star apart?"" "Colleen nodded." ""A rare event, and we're just in time for it." ""The hole swallows stars," "But first it likes to chew them up."" "He could barely make himself look as the view swung inwards" "Towards eye-Hurting brilliance." "The disc revolved about a white-Hot ball," "Sizzling with blistering energy." "Narrator:" "Gregory benford is a best-Selling author." "His science fiction is remarkably convincing," "Because he also happens to be a physicist." "Benford:" "I slowly began to realize" "That there was, at least, a case now emerging" "That there might be a black hole" "At the center of our own galaxy..." "Not just a couple of times the mass of the sun," "But a thousand times, or a million times," "And that prospect thrilled me." "I thought, wow, there's got to be" "Some great special effects on offer in a place like that." "What would it do?" "What would it be like if you fell into one," "And what would it feel like to be stretched out" "As thin as a noodle by the tidal force" "As you fall into one?" "How can you live near one?" "How would you make a living?" "Narrator:" "In science fiction," "Black holes became the ultimate cosmic monster." "They could weigh as much as a billion suns." "They could swallow matter whole, even stars," "And once one starts moving in for the kill," "There's no stopping it." "Benford:" "It becomes compact, massive, and therefore able to," "If it were to encounter something else," "Able to eat some more matter." "It becomes the eater of all things," "Because nothing survives it." "If this happens, as is most probable," "At the center of the galaxy" "Where the stars are more concentrated," "There's more dust and gas," "Then that's where you would probably first make black holes," "And then that's where the feeding trough is." "They start to eat the surroundings." "Hawking:" "Black holes were an area" "In which science fact, real scientific calculations," "Was way ahead of science fiction." "That only caught up later." "One question many science fiction writers" "Speculated on was," "What would happen inside a black hole?" "Computer calculations couldn't be trusted for this," "Because they would become inaccurate" "In the extreme conditions." "But the answer was supplied by a mathematician" "Called roger penrose," "Who, like me, had been encouraged to work" "On general relativity" "By my supervisor, dennis sciama." "Roger and his father, lionel penrose," "Wrote a paper, which i guess" "The artist esher partly made famous later," "Called "impossible objects,"" "Where you can design an object on a piece of paper..." "And esher made such designs..." "Which can't be realized in the real world." "For instance, there's a picture" "Where the steps go round in a circuit," "But they're always going down as you keep going round." "You then end up where you began," "And yet you've been going down all the way." "And you can draw something which suggests that." "But in fact," "You couldn't construct it in the real world." "Roger penrose had the kind of mind" "That would conceive relationships of that sort." "Narrator:" "Penrose grasped concepts" "No computer ever could." "But his imagination also took him to a conclusion" "Other scientists were desperately trying to avoid." "Oppenheimer's idea of gravitational collapse" "Was strange enough." "Now penrose was claiming" "The awesome power unleashed in that collapse" "Would break the known laws of physics." "Sciama:" "There was a debate going on at the time" "As to whether, in the collapse of a star in it's late stages," "It would achieve infinite density" "In the central region." "If the theory says it reaches infinite densities," "Then in a certain sense the theory has broken down" "And there would be a contradiction." "The theory would not be self-Consistent." "If our best theory of gravitation" "Is not even self-Consistent," "Then we have a crisis in physics." "The theory of relativity contains in itself" "The seeds of its own decay." "Narrator:" "It's called a singularity..." "A point of infinite density." "Most scientists thought it utterly impossible." "Sciama:" "But penrose had no such hangups," "And he showed in 1965" "That a star in its end stages" "Under natural conditions would end up" "In this self-Contradictory state of infinite density." "So the whole space-Time has gone pathological." "Narrator:" "It was a physicist's nightmare." "In a black hole," "Matter could actually exit the known universe." "Time and space drew to a close," "And physics as we know it became meaningless." "Still, dennis sciama encouraged his students to delve deeper." "Sciama:" "Stephen said to me, in a certain sense," "The universe is like a big star..." "Of course, the universe is expanding..." "If in your mind you reverse the sense of time," "Then the universe is collapsing." "It's a bit like a collapsing star," "A very large star." "Should i work on that?" "Hawking:" "I was awarded my doctorate" "For showing that the questions" "Penrose was raising about black holes" "Would apply equally well to the early universe." "Both the big bang and black holes would" "Contain singularities," "Places where space and time come to an end," "And the laws of physics break down." "Narrator:" "Singularities, it seems," "Are cauldrons of staggering energy." "In black holes," "They can consume everything in their path." "With the big bang," "A singularity willed the whole universe into being." "And what else, scientists wondered," "Could be behind the force unleashed in quasars?" "Sciama:" "They were actually applying Einstein's theory," "Not just to mathematical" "Or mathematically dominated situations on paper," "But to actual objects in the sky that were exploding." "In fact, a quasar is the most violent explosion we know of" "Other than the big bang itself." "Narrator:" "In russia," "As in america," "Scientists who had worked on nuclear weapons" "Were now tackling the unlikely physics of singularities." "But first they had to prove these black holes," "Immense yet hidden, really existed." "One set out to find the invisible," "Yakov zeldovich." "Benford:" "Zeldovich, apparently, never forgot anything." "Everything went into understanding" "How to see a black hole." "I'm sure that working on the h-Bomb" "Actually helped him in astrophysics," "Because after all, most of astrophysics" "Is forms of controlled h-Bombs." "How would you see a black hole anyway?" "You can't see it directly." "You know the lion by its paw," "Or even better by its paw print." "That's less dangerous than actually approaching a lion." "So he said, suppose you've got" "Two stars going around like this," "And one of them is a black hole," "Say this little one right here." "This black hole has a powerful gravitational influence," "And it can actually suck the gas" "Off the surface of this other star." "First it gets torn apart by tidal forces" "As it tries to orbit the black hole." "Then these shred it," "Smears it around," "And the parts bump into each other..." "They begin to grind upon each other." "The density is fairly high, and they heat up." "They heat up, they give off emission..." "Electromagnetic waves," "X" " Rays, visible, infrared..." "And from that we can see this disc of hot material." "That's one way to see a black hole indirectly." "The most gaudy way is if you've got a black hole" "That is really spending its energy account." "Meanwhile, magnetic fields" "Have been dragged into this giant salvage dump," "Perhaps, at the center of a galaxy." "These magnetic fields tend to get ordered," "And they go like this." "They come out of the accretion disc" "And peel away outside." "This set of straight field lines," "Perpendicular to the disc, means that material," "If it gets really hot," "Can take off along these field lines," "And head on out all the way..." "Perhaps with enough energy to blow off the field lines," "And to take off and leave the galaxy," "In which case you have a bright stream" "Of well-Ordered material, like water out of a fire hose," "Spewing out into intergalactic space," "And radiating, because it's still hot." "It's got lots of energy." "That we call a galactic jet." "And if you see two of them, then it's clear evidence" "That there is a kind of an interesting symmetry" "At the center of a galaxy." "You get two discs..." "sorry, you get one disc," "And you get two jets." "And those... a double pair of jets is, of course," "The most beautiful thing to find." "Hawking:" "Observational evidence was beginning to come," "But was still very uncertain." "I didn't want to see" "All my work on black holes go to waste." "So i made a bet with kip thorne," "Who had been a student of John Wheeler." "One suspects that it was" "More an insurance policy by steve," "Rather than what he really believed." "Because he bet with kip thorne..." "Claiming that black holes did not exist in nature," "Even though they existed in theory," "And he bet one year of penthouse" "Against four years of private eye" "Against kip thorne" "On the grounds that if black holes do exist," "He has to pay kip thorne a relatively modest amount," "But if they don't exist," "And all his work on black holes is wasted," "At least he gets copies of a nice magazine." "Narrator:" "While Hawking was hedging his bets," "The evidence for black holes was starting to mount." "Galactic jets had been sighted." "But this still wasn't proof." "There was no guarantee" "The emissions came from black holes." "So a new generation of astronomers" "Tried a different tact." "They began to look for stars that might be trapped in orbit" "Around a black hole." "For alex filippenko, the search was on." "Filippenko:" "You choose the ones" "That are the most likely candidates." "And those, by the hypothesis of zeldovich and others," "Were the x-Ray-Emitting stars." "So we find an object which had burst out" "Into the x-Ray world in 1988." "We wanted to wait" "Until it quieted down at x-Ray energies, because," "Along with the x-Ray outburst," "You get an outburst of optical light," "Radio light, everything." "And so what happens is, for quite a while," "The matter which is being dumped into the black hole" "Glows so much at all wavelengths" "That it completely dominates the light from the star," "Which you might find to be oscillating back and forth." "So you have to wait for a while until this thing fades," "Until the black hole stops stealing material" "From the companion star." "So we waited." "Narrator:" "They waited a long time." "After seven years," "The object they believed to be a black hole" "Began to quiet down, leaving the companion star" "Circling it in stark relief." "Filippenko and his team were ready." "Filippenko:" "We want to find as direct evidence as we can" "That a massive compact object, a dark star," "Is pulling on a companion star." "So the way to do that" "Is to measure the motion of the companion star." "Since you can never directly take a photograph" "Of a black hole, it just appears black," "The best you can really do" "Is measure its influence on material around it." "We can then look for minute shifts" "In the color of the light coming from this star," "And if these shifts are found," "And they go back and forth periodically," "Then that's an indication" "That something is tugging on the star," "Because stars on their own don't just go around," "Going back and forth," "Or going around in circles in the sky." "By newton's laws, there has to be something" "Tugging on them in order to induce that motion." "Narrator:" "With his telescope finally witness" "To the companion star," "Filippenko can analyze its light." "Okay, there's the star" "We think is orbiting a black hole." "Let's get a spectrum of it." "Narrator:" "As it orbits, its spectrum shifts." "By the amount of that shift, filippenko can measure" "The speed of the star, and the gravitational effect" "The object it's circling is exerting." "The bigger the pull, the bigger the object." "Wow, what a beauty." "It's a black hole, at least five times the mass of the sun." "Here we are, trying to prove" "That an extreme form of nature exists," "A form of nature predicted" "By Einstein's general theory of relativity," "But which is not necessarily" "Something that nature chooses to adopt." "Black holes..." "They're in science fiction and everything else," "So it's a wonderful topic, it's a wonderful concept." "Narrator:" "As the evidence builds," "Scientists have become convinced" "Black holes do exist." "Filippenko:" "Clever theorists can come up with" "Many explanations" "For individual objects." "But when you find a whole collection of objects," "All of which collectively show the same phenomenon," "That can be explained quite naturally" "Under the black hole hypothesis" "And quite unnaturally using other hypotheses" "Where you conjure up special conditions" "For each of these different objects," "That leaves you with an unfulfilled feeling." "You're thinking up a new theory for every object," "And it just doesn't sit well, you know, it doesn't seem right," "It doesn't feel right." "Yet, when you have a whole class of objects" "Which are behaving the same way," "And are well explained with one simple theory," "That gives you some confidence" "That what we're really seeing is a black hole." "Hawking:" "The evidence for black holes" "Was now so good that i no longer felt" "The need for insurance." "I conceded my bet," "And kip thorne started to receive penthouse magazine," "Greatly to the disgust of his liberated wife." "Narrator:" "In the passing of one mystery" "Comes the answer to another." "Could black holes power the brightest beacons in space?" "Filippenko:" "Quasars appear" "To be denizens of the early universe," "They just don't exist nowadays." "Yet, if they are powered by material" "Falling into a black hole long ago," "Back when the universe was young," "Then it seems reasonable that their remains" "Exist here today in the centers" "Of normal-Looking galaxies." "So that with the passage of time," "The quasar's center gradually used up" "All the gas and other material in its vicinity." "It stopped eating this material, and hence it faded with time," "Because the quasar glows" "Only while it's swallowing material." "So a natural conclusion was" "That nearby normal-Looking galaxies" "Might have very massive centers," "Which do not appear active anymore" "Simply because there's no material for them to swallow." "Astronomers have found" "Evidence of stars moving around very rapidly" "In the central region of what appears to be" "A completely boring and inactive galaxy..." "Where material seems to be going around so quickly" "In such a small space that no theorist" "Has dreamed up anything else other than a black hole" "That could be hidden inside" "The central region of this galaxy." "So black holes appear to form in the centers of galaxies." "And in particular, large galaxies" "Appear to preferentially harbor black holes at their centers." "Benford:" "The disc revolved about a white-Hot ball," "Sizzling with blistering energy." ""Why is everything so hot?"" ""Friction... all that stuff" ""Orbiting tighter and tighter around the hole..." ""It rubs up against other stuff," ""Gas, dust, and whatnot..." "Heats up."" "There's so much of it." "Whole stars are being ground down" "Into gas and dust," "And they churn against each other," "They heat up, the entire disc becomes lit up." "It's brightest at the center" "Where the velocities are highest," "Because the velocity gets higher and higher and higher" "The closer you get to the black hole." "This big shining disc, not a compact disc," "A cosmic disc," "Is visible at immense distances," "Because it shines particularly out" "In the directions perpendicular" "To the disc of the galaxy across the whole universe." "That's what we believe quasars are." "The discs and their surrounding environment," "Which also gets heated up by all this radiation" "Shining out toward us from the far past," "Because the quasars we see are all dead now." "They don't last a long time." "They're burning up their energy so quickly." "So we're looking millions and billions of years" "Into the past, and seeing galaxies" "Burning their inheritance prolificately," "So that they may send us this momentary signal." "And then they turn into cinders eventually," "They go out." "Our center of our galaxy was never in that league." "It was never a billion stellar masses," "It was maybe a million," "But once it shone more brightly than it does now." "It would have been dangerous to live right next to, then." "Hawking:" "We may now understand" "How black holes and quasars are related," "But there is plenty of mystery left." "Strange as it may sound," "I have found that things can get out of black holes." "On a microscopic scale," "There is always a bit of uncertainty" "In the speed of a particle." "This means that particles can travel faster than light" "And can escape from a black hole." "Other people call this Hawking radiation," "But i don't feel i can use the term." "Many physicists believe that this radiation" "Will be completely determined" "By what fell into the black hole," "But i think the radiation will be random" "And will not carry any information" "About what fell in." "I therefore have another bet with kip thorne on it," "But this time he and i are on the same side." "We bet against another physicist, John Friscil," "That information is lost in black holes." "The loser will buy the winner an encyclopedia" "From which information can easily be retrieved." "Narrator:" "The confirmation of black holes" "Has taught scientists it's unwise" "To resist unlikely ideas." "Seth shostak of seti" "Sees implications for his own work." "Shostak:" "In many ways, the black hole story" "Is somewhat analogous to what we're doing," "Because black holes, in fact, were found on blackboards," "Actually, before they were found in the sky." "That's not the normal way things work in astronomy." "Normally, in astronomy, you go to the telescope," "You find something you hadn't expected," "And then you try and explain it." "But black holes, they were found by theoreticians" "Years before anybody had any hope" "Of finding them with a telescope." "Well, here we have the same thing in seti." "We expect" "That the galaxy is rife with civilizations," "With technological civilizations." "That's what we expect, that's our belief," "And it's based on, i think, reasonable assumption." "Now we're using the telescope," "The radio telescope in this case," "To go out and see, well, is it actually there?" "Can we actually hear e.T.?" "Narrator:" "But there's one crucial difference" "Between the discovery of black holes" "And the search for e.T." "Shostak:" "So far, in 36 years of listening," "We have not heard a single, confirmed peep from the cosmos." "I mean, that's a fact, that's the bottom line." "Narrator:" "Still, seti enthusiasts are patient." "The question is," "Will their cosmic counterparts be, as well?" "Shostak:" "We don't broadcast in seti." "We don't send signals out." "The reason we don't do that" "Is because the distances are quite large." "If the nearest civilization is 100 light years away," "You send an inquiry, it takes 100 years to get there." "If they deign to reply, it takes another 100 years" "For their answer to come back," "That's 200 years by that point." "You've lost interest," "And your funding has probably gone away, too." "Narrator:" "While we await some faint murmur from far away," "Our imaginations are carrying us" "To the very brink of the universe." "Today, theorists talk seriously of time travel" "And what they call "worm holes,"" "Elusive tunnels in space and time," "Through which we could escape our universe" "And slip into another." "Mathematically, it's all possible." "Shostak:" "Black hole physics" "Gets down to the real nitty gritty," "The edges of what we know about physics." "And of course, that's why it attracts" "The top theoreticians," "Because it's a chance to make that breakthrough." "You're going to unknown territory." "There are suggestions that this speed limit" "On communication and transport, the speed of light," "You can't go faster than the speed of light," "And you can't send information faster than the speed of light." "But the physics of black holes suggest," "Although it's still uncertain," "That there may be other ways to send information" "Using the physics of black holes," "Or using black holes themselves." "That might imply there's some practical way" "To take advantage of that." "And if you have truly advanced civilizations in the galaxy," "And you might, remember," "We're the new kids on the block," "The earth has been here four or five billion years," "But the galaxy has been here at least twice that long," "So there may be some civilizations" "That are very, very much more advanced than we are." "They may be taking advantage of that," "And it may be that we're sitting around" "With our radio receivers hoping to get signals," "And all the really interesting traffic" "Is being communicated in a way that we're not yet aware of." "But it also has led" "To predictions that are so strange" "As to be held in..." "well, they're obviously suspect." "I mean, the idea of time travel," "The idea that you can somehow drop into a worm hole" "And come out in possibly even another universe..." "That is such a bizarre idea, and yet it's this," "These probings on the frontier" "That sometimes present you with a completely new way" "Of looking at things that make the biggest progress." "So, of course, everybody will pay lip service to the fact that" "Yes, these bizarre predictions" "Coming out of black hole research..." "Yes, well i'm not sure i believe in time travel," "Or being able to drop into a black hole" "And go to another universe..." "That doesn't sound right to me." "But they do it with great caution," "Because they've learned the lesson" "That what is today's unthinkable is tomorrow's convention." "Hawking:" "Black holes are a remarkable prediction" "Of Einstein's theory that seems to be" "Borne out by our observations." "But the theory may allow" "Even more extraordinary possibilities," "Like rapid intergalactic transit or time travel." "If it does, why haven't we been visited" "By aliens or tourists from the future?" "Of course, some people would claim" "We have been visited, and that's what ufos are." "But i think any such contacts would be much more obvious" "And probably very nasty." "To learn more about "Stephen Hawking's universe,"" "Visit pbs online at the internet address" "On your screen." "" " Captions by vitac:" "Burbank,Pittsburgh, Tampa and Washington, D.C. " ""Stephen Hawking's universe" was made possible" "By alfred p." "Sloan foundation to enhance public understanding" "Of the role of science and technology," "The arthur vining davis foundations," "The corporation for public broadcasting," "And viewers like you." "Corporate funding is provided by amgen," "Unlocking the secrets of life through biotechnology." "At amgen, we produce medicines" "That improve people's lives today" "And bring hope for tomorrow." ""Stephen Hawking's universe" is made possible" "By Alfred P. Sloan foundation to enhance public understanding" "Of the role of science and technology," "The Arthur Vining Davis foundations," "The corporation for public broadcasting," "And viewers like you." "Corporate funding is provided by Amgen," "Unlocking the secrets of life through biotechnology." "At Amgen, we produce medicines" "That improve people's lives today" "And bring hope for tomorrow." "STEPHEN HAWKING'S UNIVERSE" "AN ANSWER TO EVERYTHING" ""Stephen Hawking's Universe" is made possible... by Alfred P. Sloan foundation to enhance public understanding... of the role of science and technology." "The Arthur Vining Davis foundations." "The corporation for public broadcasting." "And viewers like you." "Corporate funding is provided by Amgen." "Unlocking the secrets of life through biotechnology." "At Amgen, we produce medicines... that improve people's lives today... and bring hope for tomorrow." "Stephen Hawking:" "In the last hundred years," "Our understanding of the universe..." "Has advanced far farther than in previous centuries." "We have discovered that the universe and time itself..." "Had a beginning 15 billion years ago." "There was a cosmic explosion of energy..." "Called the big bang." "The energy produced..." "All of the matter in the universe," "From stars and galaxies to our own planet..." "And even ourselves." "Yet one question still needs an answer." "How did the big bang begin?" "We need to know the laws..." "That held at the moment of creation" "When the universe sprang into existence." "Are these initial laws over and above the laws" "That tell us how the universe evolves?" "Or is there a theory of everything..." "That governs the universe at all times" "And determines how it begins and develops?" "Narrator: "I shall never believe." Said Einstein," ""That god plays dice with the world."" "Words that might bring gloom" "To the gambling capital of the east." "Atlantic city has two sides..." "One that's flush with big casinos," "One old and simple as a small town." "Today, physicists are grappling" "With a dual universe..." "One great as all the cosmos, one infinitesimally small," "Both a puzzle to Sydney Coleman." "Coleman:" "Physics starts out by trying to explain" "The sort of phenomena that occur in everyday life..." "Balls bouncing and planets round and round the sun," "And all that stuff." "And that's also pretty much the sort of stuff" "That you encounter in everyday life," "And your tacit assumptions about those things" "And how they behave are deeply embedded" "In the language of everyday speech." "That's how the language of everyday speech developed." "Narrator:" "But physics has now gone beyond the familiar." "Theorists like coleman spend their days" "Making imaginary journeys into strange new worlds," "Far removed from everyday life." "As physics develops" "And physicists want to find out more and more," "They try and understand physics" "Which reveals itself only under extreme conditions..." "On the inside of an atom, in a high-Energy accelerator," "In a quasar, during the beginning of the universe." "Now it would be really remarkable if the concepts" "Of everyday speech continued to be valid" "When we extend the universe of study so enormously." "It's only natural that," "As we get farther and farther from everyday experience," "The theories we have to describe all this new stuff" "In addition to everyday experience," "Should look less and less intuitive." "Why should your intuitions have developed" "To be good inside a quasar?" "Your ancestors did not spend any time inside quasars." "So things seem to get," "From our viewpoint, our earth-Bound viewpoint," "Stranger and stranger." "Narrator:" "That the universe is vast and expanding" "Is accepted wisdom." "That it began at a tiny point" "Is accepted as well." "Each extreme has its own theory to describe it." "Coleman:" "When you trace the evolution of the universe" "Backwards in time, you inevitably find yourself" "Being pushed towards the physics of the very small." "Narrator:" "The World of the Minute" "Has its own peculiar laws." "And it was at this scale," "Millions of times smaller than a single atom," "That the universe began." "The study of the subatomic realm" "Is called quantum mechanics." "Woman:" "Two foundation stones, really," "On which we've built current modern picture" "Of the universe and the matter in it" "Are quantum mechanics and general relativity." "Einstein was instrumental in both of those theories." "He was a founder of quantum theory" "And the sole inventor of general relativity." "And the picture that they give us of the universe" "Is a very good one in the sense," "We can make a lot of predictions" "And explain a lot of phenomena." "But the picture is really only partial in many ways." "And one of the problems is that the two theories," "In fact don't fit together" "Narrator:" "Einstein described" "The large-Scale universe," "A realm where gravity" "Is the dominant force." "Quantum mechanics concerns" "The behavior of atomic particles," "Governed by forces wholly different." "But a complete theory of the universe" "Has to embrace everything," "From the tiniest traces to the largest galaxy." "Dowker:" "Einstein believed" "That he could find a way to make them fit," "Because the methods that he had applied" "To problems in physics before had always worked." "He'd been very successful in unifying things." "He trusted his instincts." "So his instinct was that there should be a theory" "Which described the two theories together." "Narrator:" "In his twilight years," "Einstein pursued a quest he alone believed in." "He went his own way," "Dreaming of a single theory of everything." "Dowker:" "He spent decades on this work." "He worked basically alone." "I think that no one else shared his view" "That this was the way to go in unification." "So he was very solitary," "And he was working by himself" "Up until the day he died." "Narrator:" "Pages of his notes were found at his bedside," "But his unifying theory was unfinished." "He had failed to realize his dream." "But Einstein, as always, was ahead of his time." "Four decades later," "His quest is being pursued by others." "Theorists are rallying to find a single equation" "That can resolve the old contradiction" "Between quantum mechanics and relativity." "They, too, are looking for a theory of everything." "Hawking:" "At the beginning, the universe is a single point." "The next instant, it is enormous." "To understand this properly, we need a theory of everything," "Which is still just beyond our grasp." "However, we already" "Have some ideas why the expansion" "Of the early universe was precisely what it was." "Narrator:" "In their effort to uncover the ultimate mystery," "Scientists have intuition and intellect to guide them." "Yet slowly their search is being rewarded," "One fledgling theory at a time," "For they do have one more resource at their disposal." "With new technology comes new insight." "Observation offers inspiration." "Giant particle accelerators, such as slac," "In palo alto, california," "Smash atoms into each other." "These collisions create miniature explosions" "Producing energies, temperatures," "And pressures that mimic" "The very conditions of the big bang." "In the 1970s, a striking portrait" "Of the early universe emerged..." "One poised on a cosmic knife edge." "Man:" "What was always needed," "And nobody had really pointed this out," "Was that you had to assume" "That the expansion rate of the early universe" "Was tuned almost exactly right..." "That is, almost exactly the right expansion rate" "So that the universe would be just on the verge" "Of eternal expansion versus eventual collapse." "If one talks about the universe" "At a time of about one second after the big bang," "This tuning, this precise fixing of the expansion rate," "Had to be done to an accuracy of about 15 decimal places." "If the universe just expanded" "One part in the 15th decimal place" "Faster than we thought it had," "It would fly apart" "Without galaxies ever having a chance to form." "If the universe at one second after the big bang" "Were expanding with one number less" "In the 15th decimal place than what we thought," "Then the universe would collapse" "Before galaxies had ever had a chance to form." "To make the universe work," "The universe had to be perched just on this borderline." "Narrator:" "For 15 billion years," "Expansion has run its course in perfect measure." "What fluke of physical law" "Managed to strike this uncanny balance?" "Alan guth was pondering equations of immense complexity." "Yet the questions he was grappling with" "Were so simple," "They were the kind posed by a child." "Man:" "When i was still a kid," "I asked myself a question..." "Well, how could it happen" "That in different parts of the universe expansion" "Started simultaneously?" "Who gave the signal?" "How can i understand it?" "And then i thought that maybe when i would grow older" "I will open the books" "Which are written by clever professors," "And i will find out the answer." "When i grew older," "I found that people did not know that the question exists." "Narrator:" "A probing mind is a restless one." "Andrei linde, a russian," "Has unlocked a secret of creation." "Linde:" "During the last 15 years," "We've learned that the question can be answered." "Narrator:" "Linde, like guth, now lives in the united states." "But in the '70s," "They were on opposite sides of the world," "Unbeknownst to each other, simultaneously working" "On the same remarkable theory called "inflation."" "So, would you give me a glass of water?" "Sure." "Narrator:" "Linde and guth found a model" "For the early universe in the simplest of phenomena." "If energy had somehow" "Been trapped in a vacuum then released," "Space and time could have expanded," "Like so many bubbles." "Perhaps these bubbles had collided, united," "Then rapidly expanded as one vast bubble," "A symmetrical universe, growing smoothly, quickly," "And evenly in all directions." "Linde in moscow and guth in california" "Were kindred spirits." "Both needed to do detailed calculations" "To see if the idea could work." "One winter's evening in 1979," "Guth opened a notebook and began to write." "Guth:" "I had not yet calculated everything through, that night," "Enough to convince myself that it was a fascinating idea" "And that it would probably work." "The next morning" "I raced back to slac, and actually i kept track" "Of my personal biking records to slac," "And i set a new record that morning." "Once i got there, i whipped out my notebook" "And started continuing the calculations," "And by, i guess, the end of the morning," "I convinced myself that it did fit together." "Narrator:" "Linde was also making headway." "But it wasn't long before his proverbial bubble burst." "The numbers simply weren't adding up." "Across the globe, at the same time," "Inflation was turning out to be deflating." "Guth:" "As i continued to work on inflation," "I did however discover that there was a serious problem" "In the way that inflation finally ended." "It happened just like water boils." "A bubble would form here, a bubble would form there," "The bubbles would grow and collide" "And form an incredible morass of matter" "With tremendous non-Uniformities in it." "Would look, in fact, nothing whatever" "Like our universe looks like." "This was a serious problem that clearly required a modification." "Thank you." "You're welcome, sir." "Narrator:" "Still, guth went ahead and published his work." "Despite its flaws, the theory" "Caused a sensation." "Guth:" "All of a sudden" "My career had just changed overnight dramatically," "And it was an amazing experience that every scientist" "Should have a chance to have once in his life." "Narrator:" "In russia, it's against scientific tradition" "To publish an idea without" "All the details worked out." "Linde had labored long and hard," "Only to be outdone by his own principles." "Worse, he feared his precious theory" "Might be compromised by its premature unveiling." "Today, at long last," "Comes a rare meeting of the minds." "Linde:" "I don't know whether you know or not," "But i had an ulcer" "Which was induced by your work," "In some sense," "Because when i heard about all these ideas," "I was really, literally, thinking in these terms..." "That god could not be so stupid" "To lose this opportunity" "To make the world in such a economical way." "And when i found a solution," "The ulcer is gone." "Well, so sometimes physics helps." "Narrator:" "Linde had a new idea." "What if just one bubble of energy had inflated" "And become our universe?" "Linde:" "It was about 11:.00 at night," "And i could not keep myself from, well," "This feeling of happiness." "And i came to my wife and eventually waked her up," "And i told her, "look, it seems that i know" "How the universe could have emerged."" "I first announced a new inflationary scenario" "In the meeting of quantum gravity in moscow," "Which occurred in october '81." "And at that time, many very good physicists in moscow," "And the star of the meeting was steve Hawking." "Hawking:" "I gave a seminar" "With andrei translating." "When i said there was a difficulty" "With guth's idea of bubbles in collision," "Andrei said that the whole universe" "Could be a single bubble." "I objected," "Because the bubble would have been bigger" "Than the universe at the time." "Linde:" "In the middle of his talk," "He told that there was a very interesting idea" "Of andrei linde recently." "This was just my talk the previous day," "And i was, oh, my heaven, he's translating it." "And then he says" "But this model, this idea does not work," "And let me explain why." "And he starts talking and talking," "And i'm translating it," "And for a half an hour," "In the face of all the institute," "I was explaining to them why he knew inflation" "Just simply cannot work." "Narrator:" "Humiliation came in double doses to andrei linde." "In front of respected colleagues," "He saw his theory demolished." "Linde:" "And then i told steve," ""Would you like to actually understand the details of this?"" "And he told me, "sure."" "And then we disappeared for two hours." "All the institute was trying to catch steve everywhere," "And the famous physicist disappeared." "The whole institute was in panic." "Hawking:" "Linde and guth had given us an important idea." "Inflation accounts so neatly" "For the way the universe has to expand," "I'm sure it must be part of the final picture." "But inflation by itself" "Does not explain the start of the universe." "We still need a theory of everything for that." "And applying the theory" "To the beginning of the universe would be difficult," "Because my own work had shown" "That the equations would break down" "At the big bang." "Coleman:" "You can take" "Einstein's equations and run them backwards in time," "Not for a real universe," "Which is complicated, full of" "Lumps and irregularities," "But for a simplified model of the universe," "Where matter is distributed smoothly and uniformly" "Throughout the universe." "And when you did run it backwards in time," "You found, eventually, there was a point in which" "Everything came together at a single point," "Where gravitational fields became infinitely strong," "Energy densities became infinitely high." "Technically we call it a singularity." "Narrator:" "It is the netherworld of physical law." "A singularity like the big bang is a realm beyond comprehension," "Where logic is replaced by chance..." "Where matter is ruled by mere probability," "And scientists must resort to summing up" "The rolls of the dice." "Coleman:" "Physicists like to solve equations." "They like to say," "If this is the way things are now," "This is the way they'll be a year from now." "Once you hit a singularity, you can't do that." "The equations blow up," "And you don't know what to do with it." "This is disturbing." "People don't like singularities." "Narrator:" "The best bet" "For solving the mysteries of singularities" "Is quantum mechanics." "Coleman:" "Quantum mechanics is probably the strangest thing" "Human minds have ever thought up." "I think if 1,000 philosophers were to work for a 1,000 years," "Trying to think up something of maximum strangeness," "They wouldn't have thought up" "Anything as strange as quantum mechanics." "Narrator:" "Think of it as a game of chance." "Quantum mechanics is based on werner heisenberg's" ""Uncertainty principle."" "A subatomic particle" "Is too small to actually see directly." "We can never know with precision" "Where anything that small really is." "But as it moves," "It traces a path we can try to predict." "We can venture a bet of its probable position." "As it turns out, the uncertainties" "Taken together add up to revelations altogether certain." "Coleman:" "Strange as it is, it is apparently" "The way the universe works" "That enables us to make predictions" "About all sorts of processes involving atoms" "Or elementary particles colliding," "That are verified by experiment to amazing degrees of accuracy." "Narrator:" "The problem is the laws of uncertainty" "Only make sense for the universe" "As a whole at its moment of creation." "They can't be applied to the universe today," "To the stars and planets governed by gravity," "And with motions described by relativity." "Coleman:" "A lot of people have been trying to combine" "Quantum mechanics with gravity over the years," "A quantum mechanical replacement" "For Einstein's general relativity." "Hawking:" "I wanted to resolve the problem of the singularity." "After all, i was largely responsible" "For raising it in the first place." "Maybe one could choose a path around it." "Coleman:" "Hawking saw that the uncertainty" "That came when you tried" "To combine quantum mechanics and gravity" "Was in fact an escape route," "And could be used to get away from this..." "Avoid the singularity problem," "Which he himself had done so much to raise." "In a remarkable paper" "Done in collaboration with james hartle," "Hawking was able to solve" "A very, very simplified model of the universe." "Hawking:" "Jim hartle and i showed" "How a universe like our own" "Could be born without the troublesome singularity." "It involved the use of what is called imaginary time." "This may sound like science fiction," "But it is a well-Defined scientific concept" "That science fiction borrowed." "The idea was that in imaginary time" "The universe has no boundary," "No beginning or end." "It just curls round on itself like the surface of the earth." "Coleman:" "It was a complete quantum mechanical description" "Of everything that could be said" "About this simplified model of the universe," "And it had no singularities." "It's possible that quantum mechanics" "Is the answer to the problem of the singularity." "Hawking:" "I have to make it clear" "That the no-Boundary universe is just a proposal," "But it has some interesting implications." "Without boundaries," "The universe has no beginning and no end." "We don't have to explain its creation." "The universe simply exists." "But the consequences of the no-Boundary proposal" "Cannot be worked out fully" "Without a complete quantum theory of gravity" "That will unite general relativity" "And quantum mechanics." "We are back to the search for a theory of everything." "Narrator:" "While others turn to the heavens for their models," "Cosmologist lee smolin looks a little closer to home." "The answer to his universe is not contained" "In any mathematical equation." "Smolin:" "The hope was that there would be one simple law" "Which would have a unique solution," "Which would explain" "How the universe is," "The history of the universe, and so forth." "And that hope that all the questions" "Would be answered in a single law" "Is what has not happened." "So i wondered about this a great deal." "And i was thinking about this" "At the same time that i was reading about biology." "That led me to begin to wonder" "Whether the answers to some of the questions" "In elementary particle physics" "Did not rest in a single unique theory," "But maybe would be a result of historical accident," "And maybe there could be a process by which," "Through a series of developments" "In the early history of the universe," "Somehow the universe chose what its parameters were." "The wonderful thing about the biological world" "Is that it's so complicated." "There are so many different species," "They're so beautiful in so many different ways," "And one would think that one could not possibly explain this," "Which is of course what people thought before darwin." "What darwin discovered" "Is that there is a rational way to understand" "How such enormous variety and complexity" "Can come to be in the natural world," "Without being put there in the first place." "And the basic idea is that you have some population" "Which can reproduce itself," "That when it does so," "There are small, random changes in the characteristics," "And that these characteristics lead to differences" "In how well the creatures survive." "Narrator:" "Smolin's theory of everything" "Has a familiar ring." "It's inspired by darwin's idea of natural selection." "Smolin:" "The universe, like the biological world," "Seems to have discovered all sorts of ways" "To keep itself out of equilibrium and to keep" "An enormous variety of things going on." "And the universe also invents life," "Which is very impressive," "And many cosmologists have wondered," "How could it be that all of this" "Improbable structure and organization comes to be," "Out of the world that evolves out of the big bang." "Narrator:" "Imagine the universe as a product" "Of the same evolutionary processes" "That later gave rise to us." "Smolin:" "If one studies astronomy" "On scales much, much larger than the earth..." "For example, the disc of a spiral galaxy..." "One discovers it's a complex, self-Organized system," "Somewhat akin to biology on a much simpler level." "It turns out that" "The ideas by which we understand the patterns on sea shells" "Or the stripes on an animal's coat" "Are very close to the ideas by which we understand" "How the galaxies get" "Their beautiful spiral structures." "What occurred to me was maybe the explanation" "For why the parameters of the laws of physics" "Are right to produce all this complexity" "Is like the explanation of biology." "The new possibility which darwin gave us" "Is that a system can have all the beauty" "And variety and complexity of our world" "And be assembled from itself," "That it can organize itself over time." "What 20th-Century science" "Is leading to is, in my view..." "And of course, could be wrong..." "The culmination of this view of the universe" "As something which does create itself and assemble itself." "Of course, it's a new idea," "And it's very, very far from being demonstrated," "Although i must say that i'm very struck by the fact" "That it wasn't proved wrong yet." "But the idea that maybe the universe as a whole" "Organized itself by some natural process" "Makes one feel more at home." "Narrator:" "What preceded creation?" "The theorists who are exploring the question" "Are pioneers, standing alone at the frontiers" "Of an impenetrable wilderness." "For andrei linde, this lonely pursuit" "Was taking its toll." "'85 was the first year of perestroika," "So the first year of perestroika," "Gorbachev just came to power," "And they started reconstructing everything," "Which is a translation of the word perestroika," "The reconstruction." "And as a first step," "They'd completely forbidden us to send our papers abroad," "So i had a feeling that i am living with my mouth shut." "I cannot tell others what i am doing," "And this was pretty depressing." "So i became so much depressed" "That i actually became simply ill," "And now i was lying in the bed" "For about a month and a half, and then, all of a sudden," "There was a call from academy of sciences." "They told me that i must go to italy" "To give some popular lectures on astronomy." "And i told them, "i am ill, i cannot go."" "Narrator:" "He'd suffered years of frustration" "And months of repression." "Now linde was suddenly free to say what he liked." "He had 24 hours to find something worth saying." "Linde:" "After this year with the mouth shut," "They are suggesting to me that if i do something," "Then tomorrow it will be sent there" "By diplomatic mail without any approvement," "Without any signatures," "Without any of this bureaucratic work." "Tomorrow it will be in italy." "On the other hand, it must be done just immediately," "And i am really sick." "I just cannot." "I took my head like that, and i started thinking," ""What can i invent within half an hour or so?" ""I will write it today in the evening," ""And tomorrow i'll send it to italy." "What can i do within half an hour?"" "And within half an hour," "I have got a theory of self-Reproducing universe." "Narrator:" "In linde's new theory," "Inflation must have produced a multitude of universes." "Instead of just one growing, there had to be many..." "Each universe different," "Each the product of its own big bang." "In time, they will seed other universes" "So the process goes on forever." "Linde had experienced his own conceptual big bang." "Out of depression had come pure inspiration." "Linde:" "When i was really going to italy," "I had four papers written" "On the theory of self-Reproducing universe." "I smuggled them to italy without any permission," "And i came to rome, and i gave lectures in rome." "I came to torino, i gave lectures in torino." "I came to trieste, and i gave the lectures," "And then they delivered my body to the railway station" "And put me into a luxurious sleeping wagon," "And i looked into myself in the mirror..." "This was '86, where i was 38 years old." "I looked in the mirror" "And i have seen the body of an old person," "Slowly moving from trieste into the direction of rome." "And then, after a while, i became healthy again." "And since that time i did not have such a depression," "Which in a certain sense may be unfortunate." "Hawking:" "Smolin and linde's evolutionary theories" "Have failed to catch on." "Most cosmologists, like me," "Still want to find a single explanation" "Of a single universe." "Narrator:" "In 1985, a promising new theory emerged," "Raising hopes the search would soon be over." "You're tuned to wbai, 99.5 fm on your dial." "Coming up next, "explorations" with dr." "Michio kaku." "Welcome." "This is "exploration."" "This is dr." "Michio kaku," "Professor of theoretical physics," "And this is a program devoted to science" "And the fantastic discoveries as we explore the universe," "And of course, super string theory," "The theory that will perhaps" "Give us an explanation for the entire universe." "Some people say the instant of the big bang," "The universe was a dot." "The new picture is that it's like a bowl of noodles," "A bowl of noodles where we have" "Thousands and millions of little strings," "Vibrating at the instant of time," "That exploded, creating" "The enormous diversity of matter and energy" "That we see around us." "Super string theory is so bizarre, so strange," "That we were not destined to see this theory" "In the 20th century." "Many of us believe that it's really 21st-Century physics" "That fell accidentally" "Into the 20th century." "Narrator:" "Bubbles have their proponents," "Uncertainty has its adherents," "But strings are the stuff of zealots." "It's based on a rarefied branch of mathematics," "And it's an idea so ahead of its time" "That its time may not yet have come." "Kaku:" "Einstein spent the last 30 years of his life" "Trying to create a theory of everything," "A theory of black holes, of galaxies," "And a theory of atoms, of light, of force." "So we have two great theories of physics..." "The theory of the very big, Einstein's theory of relativity," "And the theory of the very small," "The quantum theory." "And these two theories" "They are incompatible." "One is smooth, beautiful, like marble," "And the other one is coarse and grainy like wood." "And to get them to meet together has been the object" "Of the last 50 years of intense investigation." "Today, we think we have it." "We think we have the super string theory," "Which is perhaps the most fantastic," "The most marvelous theory ever proposed" "In the history of science." "Narrator:" "String theory borders on mysticism." "It contemplates a universe" "Strewn with minute strands of space-Time." "Kaku:" "Strings are extremely tiny," "Like 100 billion billion times smaller than a proton," "So let me explain." "Take an atom, and expand it to the size of the solar system." "If the atom were the size of our solar system," "Then a string is much smaller than that." "A string is the size of an atom." "That is how incredibly tiny this all is." "We also think that once upon a time" "The universe was the size of a string." "When strings move, they vibrate." "And when they vibrate," "Each note of this vibrating string" "Corresponds to a particle." "So if i had a microscope" "That could peer into an electron or proton," "I'd see a vibrating string." "My own body is essentially a symphony of vibrating strings." "But when strings move, they force the space around it" "To curl up, to bend," "Exactly as Einstein had predicted." "Narrator:" "Strings are the theorist's darling." "They are a structure hatched specifically to cater" "To the discrepancies" "In the divergent theories of physics." "True, they are wholly abstract, and have little basis" "In reality so far," "But at least they may" "Provide the ties that bind" "The two great schools of thought." "We physicists have been puzzled by the fact" "That we have matter, like atoms," "And we have forces, like gravity," "That attract atoms." "Now we realize that this dichotomy" "Between force and matter" "Is really not a dichotomy at all." "These are nothing but vibrations of the same string." "One string that vibrates could be a quark." "Another string that vibrates could be an electron." "But yet another string that vibrates" "Could be light, a photon, or Einstein's theory of gravity." "Narrator:" "String theory, at its heart," "Is a search for perfection," "To conjure a vision of creation" "Of consummate order and purity of form." "Kaku:" "Now, if you look at clouds or rocks or mountains," "We don't see symmetry at all." "But as we go backwards in time," "As we get closer and closer to the big bang," "We realize that there's a beautiful," "Gorgeous, magnificent symmetry" "That we begin to see emerging as we go backwards in time." "Now, we believe" "That at the instant of the big bang" "There was perfect symmetry." "The only theory which gives us this perfect symmetry" "Is the super string theory." "Narrator:" "Theorists today are walking a fine line" "Between models of the universe based on images" "We can make concrete," "And concepts that seem, for now, beyond the imagination." "Kaku:" "These equations are well-Defined," "They're well-Known," "But some people think that perhaps we humans" "Are not smart enough to solve them." "Think of a duck or a monkey." "Why should a duck or a monkey understand calculus" "Or electric fields or black holes?" "And why is it that we have the power" "To understand the big bang and the black holes?" "And then the question is," "Are we smart enough to understand" "The theory of everything?" "At the present time, no." "Hawking:" "By the end of the '80s," "I and a number of other physicists" "Were beginning to wonder if string theory" "Really was the ultimate theory of the universe." "Narrator:" "In fact, string theory is no theory at all," "For a theory, by definition, must venture some predictions" "That will ultimately be put to the test of reality." "Sublime and conceptually perfect as string theory is," "It needs someone to come to its rescue." "Kaku:" "In the last several years," "We've been in the wilderness." "The mathematics has proven too difficult" "To solve super string theory." "The theory is smarter than we are." "The creative engine behind super string theory" "Is ed witten of princeton." "In fact, scientific american once said that ed witten is" ""The smartest man on earth."" "And if anyone is smart enough to solve super string theory," "It's probably going to be ed witten." "Witten:" "String theory is a mathematical structure" "Of a richness and subtlety we don't understand well." "There are many pieces of it that we've come to understand," "And they, by themselves," "Are quite elaborate stories in their own right." "We don't yet have" "A complete overview of the whole subject." "It seemed pretty clear that if there was a chance" "To go way beyond our familiar understanding of physics," "String theory was the most ambitious prospect." "It also was clear then, as it is now," "That it is a very long-Term proposition." "Narrator:" "Ed witten has taken on the challenge" "Of tackling some of the most difficult mathematics" "In the scientific world." "Witten:" "I wasn't originally interested in maths." "I was interested in doing physics." "And i remember very well" "Having some reticence" "For quite some time about" "Making the 100% commitment," "Of really deciding that was going to be my life." "Narrator:" "Witten's quest is to turn out" "Countless consuming mathematical constructions." "One, he hopes, will someday get strings" "To actually describe the world." "Witten:" "The question was," "How realistic was it as a theory of nature?" "My main interest was to make it more realistic." "For a few years there were very exciting developments," "And then we went through a period" "Where the progress was slower and more subtle." "We were dotting i's and crossing t's" "And understanding details." "We were discovering things that were strange and beautiful," "But perhaps not of such wide ramifications" "As the things done in the mid-'80s." "So things were slow" "And the developments, i guess, were more mathematical." "String theory, as it had developed by the mid-'80s," "Was characterized by the fact" "That there were five theories we knew about." "And that raised the rather curious question" "Which was always a little bit embarrassing." "If one of those theories describes our universe," "Then who lives in other four universes?" "We've come to understand" "That those five theories we've been studying" "Are all limiting cases of one bigger picture." "In the last couple of years, the picture has really changed" "Through something which is called duality." "Duality is a relationship between two different theories," "Which isn't obvious." "If it's obvious, you don't dignify it" "By the name "duality."" "So we have different pictures." "And it's not that one is correct" "And the other one isn't correct." "One of them is more useful" "For answering one set of questions." "The other is more useful" "For answering another set of questions." "And the power of the theory" "Comes largely from understanding" "That these different points of view" "Which sound like they're" "About different universes" "Actually work together in describing one model." "And i might say that 10 years ago" "It just looked impossible that those theories" "Would turn out to all be one," "So it's a big conceptual upheaval" "To understand that there's only one theory" "Which is our candidate for nature." "To make an analogy" "With the blind men and the elephant," "There is the guy who discovered the trunk," "And there's the guy who discovered the tail," "And there's the guy who discovered the ear." "And in the past we thought" "They were five different things." "Now we know there is one elephant." "We still don't understand that elephant too well." "Narrator:" "Witten remains convinced" "String theory can be borne out." "His conviction has its price." "The new world he's charting is a lonely one." "It is populated only by strange and abstract ideas," "By many dimensions," "Rather than the three the rest of us know." "A lot of people, even professional physicists," "In my opinion, don't fully grasp the scope and richness" "Of the structure involved." "People may tend to be too impatient for quick results" "In some cases." "I think that there are a lot of reasons" "To think that a structure" "Which is so rich and so physical" "And which has been the source," "The continued source of so many beautiful discoveries," "Must be on the right track." "Narrator:" "Witten is widely regarded" "As the heir apparent to Einstein." "On he struggles, with little assurance" "His work can be completed in his lifetime." "Witten:" "When you are doing a calculation," "It's usually on some very specific detail." "That's a tiny, tiny piece of the big picture." "And you're hoping that that piece will shed light" "On the big picture." "Sometimes it does, but usually it doesn't." "Oftentimes you come home" "At the end of the day," "And you know exactly the amount you knew" "At the beginning of the day." "But sometimes you know a little bit more." "I think that this investigation" "Is the richest thing that physicists can tackle now." "How far we'll get in our lifetimes," "There's no way to know." "We might get the answers we dream of getting." "We might fall well short." "But i think we can accomplish something," "A faith which i'd say is well-Vindicated" "By the duality revolution of the last couple of years." "I think we can accomplish more in the future," "And getting as far as we can is the best we can do." "Hawking: 20 years ago," "I said there was a 50/50 chance" "We would have a complete picture of the universe" "In the next 20 years." "That is still my estimate today, but the 20 years starts now." "It's very hard to build" "A fully consistent quantum theory of gravity." "The string theorists think they have one." "They may or may not be right." "They haven't yet pushed their theory far enough" "So you can compare" "The consequences of string theory to experiment," "And that's what you ultimately need." "Narrator:" "While theorists around the world" "Pursue their lone predictions," "Many are pinning their hopes" "On a singular mission." "Neil turok is preparing for a journey into the unknown." "He's about to explore a place called the past." "When he gets there," "He'll tell us what it looks like." "Turok:" "Imagine you were trying to navigate across a continent," "And you had a map which only showed features" "Greater than 100 miles across." "It wouldn't be much use in finding your way" "Along a particular route." "But if you have a map that has a resolution of a mile," "Then that becomes much more useful." "Narrator:" "Turok is setting out" "To make the map of all maps with a satellite" "He plans to help launch early in the 21st century." "It's called the planck explorer." "Turok:" "What we'll do is look out," "Map the whole sky at a very high resolution." "Basically, this is equivalent to making a map of the earth" "Where you show all the rivers and the mountains" "And the valleys in exquisite detail." "And this map will contain a vast amount of information." "It will give us" "The best picture we have of the universe." "Narrator:" "The planck explorer" "Will be able to detect energy that was emitted" "Billions of years ago at the dawn of the universe." "For a study that has too long" "Searched for answers in the mind's eye," "It might provide a vision of sheer clarity." "Turok:" "It is a map of the universe" "At very early times." "We're not sure quite when the radiation" "From the big bang was emitted from the plasma" "In the early universe," "But when we look out and we see the sky," "We're looking directly" "At different patches of hot plasma," "And they are going to be" "At slightly different temperature," "And so this will be a map" "Of the temperature variations on the sky." "Narrator:" "In those subtle vestiges of the big bang" "Are the secrets of its inception." "They will bear the signature of creation," "And with any luck," "The revelation that will clinch which theory wins the day." "The time may soon be at hand to know the ultimate truth." "I think people are usually" "Excessively confident about the theories," "Because there has been an absence of data," "And that's allowed people" "To be confident about the theories." "The current theories there are, are all based" "On very clever ideas and very imaginative ideas," "But what's really good about them is" "They do give you a well-Defined framework" "Within which you can make predictions." "Narrator:" "We've already glimpsed the temperature fluctuations" "Of the big bang, but never in sufficient detail." "Each theory of everything predicts a different outcome" "To turok's experiment." "Perhaps he will at last settle the question," "Or perhaps he'll only raise more." "Turok:" "We're in the wonderful situation now" "Where over the next 5 or 10 years," "The theory is going to be beaten to death," "Or theories that we have will be beaten to death" "In terms of making predictions." "That will all be settled," "And they'll all say exactly" "What they expect to find on the sky." "And then this satellite will fly" "And will map the sky to very high precision," "And we'll see what happens." "It's a very exciting time to be involved." "It's a unique opportunity in science where you're told," "Within 10 years we're going to have the data" "That will prove or disprove" "Any theory of how structure formed in the universe." "And you've got 10 years," "So we'll see if anyone gets it right." "Hawking:" "It could be that in a few years" "We will have a complete theory that is confirmed by experiment." "It would be a remarkable achievement," "Perhaps the ultimate triumph of science." "But knowing how the universe works" "Is not enough to tell us why it exists." "To find the answer to that question" "Would be to know the mind of god." "To learn more about "Stephen Hawking's universe,"" "Visit pbs online at the internet address" "On your screen." "" " Captions by vitac:" "Burbank,Pittsburgh, Tampa and Washington, D.C. " ""Stephen Hawking's universe" was made possible" "By alfred p." "Sloan foundation to enhance public understanding" "Of the role of science and technology," "The arthur vining davis foundations," "The corporation for public broadcasting," "And viewers like you." "Corporate funding is provided by amgen," "Unlocking the secrets of life through biotechnology." "At amgen, we produce medicines" "That improve people's lives today" "And bring hope for tomorrow." "STEPHEN HAWKING'S UNIVERSE" "SEEING IS BELIEVING" ""Stephen Hawking's Universe" is made possible... by Alfred P. Sloan foundation to enhance public understanding... of the role of science and technology." "The Arthur Vining Davis foundations." "The corporation for public broadcasting." "And viewers like you." "Corporate funding is provided by Amgen." "Unlocking the secrets of life through biotechnology." "At Amgen, we produce medicines... that improve people's lives today... and bring hope for tomorrow." "Where do we come from?" "How did the universe begin?" "Why is the universe the way it is?" "Good morning." "Welcome to Gonville and Caius," "More commonly known as Caius college." "Caius college was founded in 1348" "By Edmund Gonville." "Where are we going?" "Now we come to the portrait" "Of probably our most famous caiusan," "Professor Stephen Hawking, the world-Famous cosmologist." "Like predecessor sir Isaac Newton before him," "He is lucasian professor of mathematics" "For the university," "And his particular sphere is research of the black hole" "And the history of the universe," "Culminating in his book "The Brief history of time"" "Which worldwide has sold over 8 million copies." "Hawking:" "All of my life, i have been fascinated" "By the big questions that face us," "And have tried to find scientific answers to them." "Perhaps that's why i have sold more books on physics" "Than madonna has on sex." "Now this is professor Hawking's study," "Which he will use when he's in residency in college." "He'll use this for his tutorials or meetings" "Or any private work he needs to do." "It is very much a personal room with his books" "And his portraits and pictures, so it's really a home from home" "When they're in college." "He's got an inherited disease, motor neuron disease." "He can project his voice with a synthesizer" "Which is attached to his wheelchair." "Hope you enjoyed your visit." "Bye." "Bye." "If, like me, you have looked at the stars" "And tried to make sense of what you see," "You too have started to wonder what makes the universe exist." "The questions are clear and deceptively simple," "But the answers have always seemed well beyond our reach" "Until now." "Narrator:" "Our view of the universe" "Has long been shaped simply by what we could see." "For thousands of years, that meant we understood" "Only what the naked eye could behold." "Now, new breakthroughs in science and technology" "Are rapidly advancing our horizons." "We are witness to the very brink of time and space." "Hawking:" "I want you to share my excitement" "At the discoveries, past and present," "Which have revolutionized the way we think." "From the big bang to black holes," "From dark matter to a possible big crunch," "Our image of the universe today" "Is full of strange-Sounding ideas" "And remarkable truths." "The story of how we arrived at this picture" "Is a story of learning to understand what we see." "Narrator:" "With every century," "Our eyes on the universe have been opened a new." "Only 75 years ago," "At the mount wilson observatory in california," "A young astronomer peered into a now-Primitive telescope" "And forever changed our understanding of the heavens." "His name Edwin hubble." "We know, thanks to hubble, that" "Altogether within the limits" "Of the observable universe" "There's something like 100 billion trillion stars." "It's a lot of stars." "And we now know thanks to recent discoveries" "Very recent discoveries also" "What we had believed but had no proof of," "And that is that many of those stars have planets." "So there are countless trillions of planets" "In the observable universe." "Narrator:" "This was among hubble's" "Most striking contributions" "Even as it was for his predecessors." "The more we learn about the universe," "The humbler the role we seem to play in it." "Jastrow:" "Two-Thirds of the stars and planets" "And life, if it's there, in the universe" "Are billions of years older than we are." "And if you ask what a billion years means" "In the history of life, i must tell you" "That a billion years ago" "The highest form of life on the earth was a worm." "Three billion years ago," "The highest form of life on the earth were bacteria." "So we must ask ourselves," "We who are so proud of our accomplishments," "What is our place in the cosmic perspective of life" "If most of those beings out there," "If they are there, stand in relationship to us" "As we do to the worms on this planet?" "And that is not meant to be a denigrating remark," "But only to suggest that humankind's greatest experiences" "Still lie ahead of us." "Narrator:" "It was the sumerians and babylonians" "Who first studied the workings of the heavens." "Tions laid the groundwork" "For the ancient greeks who followed." "They could see the stars" "And wonder about the sky and the heavens" "But they had very little information indeed" "Just what their eyes could pick up." "They thought that everything they knew came out of the water." "Obviously water was a very important substance," "And so they gave water a sort of cosmic significance." "They thought that the heavens are made of many holes," "And these holes represented the stars," "And just behind they had this divine fire." "Narrator:" "The Greeks had long explained what they saw" "With myths and legends." "Now they began to use reason." "Cotsakis:" "They thought that they had to find" "A more accurate way of expressing" "Their views about the universe," "And that way dramatically turned out to be mathematics" "Narrator:" "The science of logic was born," "And long-Held assumptions were called into question." "Cotsakis:" "When you see from the distance" "A boat coming," "You don't see the whole boat in the beginning," "But you gradually see the boat appearing" "From the horizon as if it was raising up from the sea." "So in this way they questioned the view" "That the earth was flat." "Narrator:" "Proof that the earth was round" "Would have to be persuasive." "A philosopher named eratosthenes" "Devised one of the first scientific experiments." "Identical objects on a flat earth" "Should cast identical shadows." "So at the same time of day," "In two places miles apart," "He put this to the test." "It was a beautiful way that he discovered" "Where he used two sticks." "He noticed that the rays coming from the sun" "Produced different amounts of shade" "In each of the two sticks." "Narrator:" "Since each peg cast shadows of different lengths" "The earth's surface had to be curved." "From the angle of the shadows, eratosthenes could estimate" "The earth's circumference at 25,000 miles" "Less than 100 miles off today's measurements." "To its first students," "The earth itself submitted to its laws." "Mathematics was the discipline" "That endowed the greeks with ultimate truths." "Cotsakis:" "They realized" "That they can use mathematics to develop" "Theories and applications" "To all sorts of different kinds of phenomena." "Hawking:" "But mathematically beautiful theories" "Are not always supported by observation." "In the earliest days of astronomy," "The ancient greeks found the heavens" "Less perfect than they had first imagined." "Looking at the skies more closely," "They began to see stars move" "In a way which defined their logic." "If every night you go out" "And you have a careful look seeing towards south," "After two or three days" "If you watch again you'll see five stars." "And this is something unusual" "In respect to the other stars of the sky" "Which don't change any position." "They look as moving from west towards the east." "Sometime they look staying still." "Then they begin to move from the east towards the west" "Narrator:" "The Greeks had identified" "Five heavenly bodies that neighbored us." "They dubbed them "planetos" or "wanderers."" "They believed in a universe in perfect balance." "The planets, they were convinced," "Were precise globes," "Traveling in sublime circular orbits." "But observation said otherwise" "It was the astronomer ptolemy" "Who tried to explain the discrepancy with math." "He made adjustments to the planets' orbits," "Retracing their paths as circles within circles," "All neatly fitting within a sphere of fixed stars." "At the center of the universe" "The earth." "Ptolemy lived over a century after the death of christ." "The new christian church" "Was quick to seize upon a model of the universe" "That imagined us, god's pride, at its center." "Papathanassiou:" "The cosmology of the church" "Is the cosmology of the genesis," "And if something has the same ideas" "As they are described in "genesis," it's okay." "For those who could understand" "The mathematics of ptolemy's model," "Well, it's a model which can foretell" "The position of the planets" "With an accuracy which is satisfying." "And on the other hand there is nothing" "Which can contradict the idea of the genesis." "3, 2, 1, zero," "Liftoff!" "Hawking:" "Today, the claims of the scriptures" "Are being put to the test" "By experiments launched into the heavens." "Steady improvements in technology over the years" "Have enabled us to test our theories" "About the universe." "But before such detailed" "Observational evidence was available," "Belief in any theory was often" "As much a matter of faith and conviction" "Ptolemy's model of the universe" "Went virtually unchallenged for 1,500 years," "Supported all the time by the church," "Which was at that time the repository of learning" "Lord, receive our gifts." "Let our offerings make us holy" "And bring us salvation." "Narrator:" "Ptolemy's vision prevailed" " Of a universe that acknowledged our supremacy." "Of an earth that, after all, did not seem to move." "And if simple experience weren't enough" "To lend ptolemy credence," "He had the support of the authorities as well" "The catholic church, by and large," "Through the centuries, say, from ptolemy" "For 1,000 years A bit more " "Was the educated world." "Ptolemy thought that it wasn't really sensible" "To have anything but the earth as the center, not so much" "For astronomical reasons, but because, after all," "If you're not used to it, it does seem incredible" "That the earth can be moving" "And ptolemy catalogued" "Quite a few of the obvious reasons" "Which affront common sense" "Like, why aren't we hurled off a rotating earth?" "How could the birds fly if there was a constant gale blowing?" "And so on." "So that, i think, weighed fairly heavily with ptolemy." "Narrator:" "By the 16th century, ptolemy's followers were faced" "With increasingly contradictory observations" "The church's teachings would soon enough be undone" "By one of its own scholar-Priests." "Sharratt:" "Nicholas copernicus was a church man" "Not just in the sense he was catholic," "But he actually held" "A church office as a canon" "Of a cathedral." "He had a great admiration for ptolemaic astronomy." "Lacked a certain elegance for copernicus" "He found he could better explain observations" "If he made one staggering shift." "He put the sun," "Not the earth, the center of the universe." "Hawking:" "It was a revolutionary moment for cosmology." "Copernicus had radically re-Organized" "The model of the universe which had lasted for centuries." "He began an irreversible process" "That has downgraded us from the center of the universe" "To the outer suburbs" "Of one among billions of galaxies." "Narrator:" "For the church, though," "Copernicus' model amounted to heresy." "God had put man on earth," "And the earth at the hub of his creation." "Copernicus died in 1543," "His life's work dismissed but not forgotten." "Some 60 years later," "Johannes kepler, a german mathematician," "Took up his work." "Sharratt:" "He broke with 2,000 years" "Of philosephical and astronomical tradition." "What kepler finished up with was non-Circular motion." "He realized that the planets" "Are actually traveling in elliptical orbits." "The great thing about kepler's system" "Is he can do everything copernicus did simply with the one clear curve of the ellipse" "In a colossal achievement." "Narrator:" "At first, the church failed to comprehend" "The dramatic change coming" "But when galileo galilei, an italian scientist," "Dared to publish copernicus' heretical idea" "The vatican took action." "Man:" "We are now at the top floor of the villa il juliello" "In the place where galileo" "Spent his last 10, 15 years of life," "The most dramatic part of his life," "As a prisoner being condemned not to leave the house," "Not to receive guests." "And that's why this was a place at the beginning very happy," "At the end, very sad for him" "Isolation was torment for galileo" "But, in solitude, his studies came into sharp focus." "The only work he could perform" "During the period in which he was prisoner" "In his own house was the completion" "Of the laws of motion." "Narrator:" "Kepler's model" "Had raised some boggling questions." "For day to follow night," "The earth would have to rotate at a thousand miles an hour." "Why, then, didn't we fall off?" "Your first impression Everybody..." "A kid for instance, 5 years old," "Not yet going to school," "You ask him if the earth is in motion," "He will say no." "He will not have any idea, any possible idea." "This is what was the situation, not just for kids," "But for everybody time of galileo." "Narrator:" "That the earth was moving," "Galileo had no doubt." "He realized we were unaware of its motion" "Simply because as it moved we moved with it." "But he could not explain what force" "Keeps us fixed to its surface." "As he studied the laws of motion," "Galileo longed for a clearer view of the firmament." "Galuzzi:" "At the end of 1609 he heard" "That there were into the market" "Some funny objects which were a tube with some glasses," "Were giving some funny performance." "This instrument" "Was coming from holland" "And was sold as a toy." "When galileo took it, it began to be transformed" "From a toy to an instrument." "He started to use" "The magnification power of the telescope" "To look at the skies." "This is a major step in his career" "And also in the history of modern cosmology." "Narrator:" "This novelty trinket, remodeled as a scientific tool" "Was to revolutionize our vision of the heavens." "At once galileo was witness to worlds we had only imagined" "According to the church," "They should have been perfect spheres" "Orbiting the earth." "They were not." "Galuzzi:" "The moon was not so polished" "And so round as people believed," "But they were presented" "Valleys and mountains exactly as the earth." "And he moved afterwards to other bodies." "He started to observe mercury, mars" "But he was captured by jupiter" "He started to observe, seriously," "Jupiter in january 1610," "And his diary note is very touching." "It says, "i have discovered a funny body," "Something like that which is circulating around jupiter,"" "7 january, if i remember correctly." "And the day after," "He was immediately at the sunset at the telescope" "Narrator:" "Struck with disbelief, he sketched what he saw." "Galuzzi:" "In a few days he became aware" "That those moons as he called them were four," "And they were satellites because they were doing" "Rhythmic and cyclic performances around the body of jupiter" "Narrator:" "Something orbiting jupiter" "Could not be orbiting earth." "The church's model of the universe was shattered." "Why galileo became convinced" "So he started to publish" "And started to produce work saying, be careful." "We cannot stay anymore with ptolemy." "What the bible was saying in many times" "About the position of the sun" "And the motion of the sun around the earth" "Was not tenable anymore." "Galileo entered a fight with the authorities." "The book of copernicus was suspended" "And sent to correction." "Galileo was called to rome at the tribunal of inquisition" "Finally he was condemned." "Narrator:" "Threatened with death at the stake," "Galileo retracted his claims" "He was sentenced to spend the of his life" "Under house arrest." "Galuzzi:" "It's the beginning of the conflict between science and religion" "Science and theology," "And it's a tension which is going to be" "Many other episodes during the modern age." "Narrator:" "Galileo's voice could be stilled," "But his spirit could not." "the spark he lit caught fire , and for those who followed" "Observing the sky became a consuming quest." "To this day, we peer into space" "With the same sense of wonder he felt." "Observing is almost mystical." "It's the act that really puts me in contact" "With the rest of the universe." "I often think if somebody' s looking back at me" "I wonder if their telescope is bigger than mine." "Narrator:" "Today's telescopes depend in part" "On refinements introduced" "By a man born the year galileo died" "Isaac newton." "Hawking:" "I feel i have links to both newton and galileo." "I now hold the same professorship at cambridge" "That newton once held," "And i was born 300 years to the day after galileo died." "But at least" "Half a million other babies" "Were born that day." "Man:" "Isaac newton" "Was born here in this house in woolsthorpe" "On christmas day, 1642." "Newton, by all accounts, was a very difficult man." "His father died" "Before he was born." "His mo" "The rather rich rector in the neighboring village." "Newton was left here in woolsthorpe" "At the age of 3," "And was brought up for the next seven or eight years" "By his grandmother." "So i think he probably had a sense of insecurity." "Narrator:" "The year was 1660." "The world of astronomy was filled with questions" "And ripe for change." "Barbour:" "At cambridge, more or less by chance," "He picked up about four or five books on mathematics," "And he set to work to read them." "Six months later he was making" "Important contributions to mathematics." "18 months later he was" "The greatest mathematician alive." "It's just staggering." "he taught himself, just from four or five books" "And it all came out of that." "Narrator:" "Newton didn't lack ambition." "He set his sights on tackling mysteries" "Galileo had left unsolved." "He bettered his chances" "By incorporating an internal mirror in the telescope," "Doubling its power." "Barbour:" "The news of this telescope" "Was distributed around europe," "And that's actually what made his name." "And later on, that design of telescope" "Turned out to be the best one of all" "For studying the heavens," "So in that way he greatly advanced astronomy." "Newton had been at cambridge for several years" "When the plague forced him" "To come back home here to woolsthorpe." "And at the time he'd left cambridge," "He was beginning to think about the laws of motion," "How things are moving," "And he had the idea that basically things" "Would essentially move in a straight line" "If they were left on their own" "He was beginning to think about the forces" "That might be at work," "And one of the most obvious is the pull of gravity," "Which is pulling an object towards the earth." "Narrator:" "Newton's discovery became the stuff of myth.." "Remember the story of the apple falling from a tree?" "I think it probably is true" "S that he did start thinking about these thing" "From seeing apples fall," "But i'm absolutely certain he didn't have" "The complete theory of universal gravitation back here in the plague year" "And the full working out came much later." "His idea of gravity" "And he called it universal gravity" "Because that is a very important thing" "Is that every single piece of matter in the universe" "Pulls every other piece" "Of matter in the universe towards it, and vice versa" "The earth is billions of times more massive than the apple," "So basically the earth is moving" "Ever so slightly towards the apple," "But you just can't see that." "The motion of the apple is much more pronounced" "Than that of the earth." "The importance of the apple is that it symbolizes the idea" "That the laws of nature that are working on the earth" "Are also working throughout the whole universe." "Narrator:" "Newton's crowning achievement" "Was to unite all that had preceded him." "He applied his theory of gravity" "To the heavens kepler described," "Then united galileo's laws with his own." "he described the path of the moon around the earth" "Then looked beyond." "Barbour:" "And that was enough to give newton the hints" "To then apply those same techniques of galileo," "But now to the planets." "And that essentially was the whole of the universe." "Narrator:" "With one sweeping theory," "Newton had redefined the cosmos." "He had solved the mystery of what kept us on earth," "What kept the earth moving , what set the stars in motion" "Even the church had to bow to the inevitable." "The ptolemaic system" "Had surrendered to one word Gravity." "Barbour:" "He was the first person" "Which manifestly worked." "And the title of his great book, the"principia,"" "That real makes the point" "He described it as the mathematical principles" "Of natural philosophy." "Hawking:" "Newton's equations" "For gravity explained the elliptical orbits" "Of the planets perfectly." "Kepler and copernicus were vindicated." "According to newton's theory" "The universe ran like clockwork forever." "I think people were comforted by the thought" "That even though they grew old and died," "The universe was eternal and unchanging." "Narrator:" "With new telescopes based on newton's design" "With a new vision of the sky based on his theories" "Stargazing became popular." "It was the age of gentleman astronomers." "Man:" "I am william brendan, the 7th earl of rosse," "Great-Great-Grandson" "Of the 3rd earl, who was also another william" "His great achievement was the building" "Of the great 6-Foot telescope," "Or leviathan of parsons town, as it was called," "That was the biggest and the most powerful telescope" "In the world up till the present century." "Narrator:" "Brendan's great-Great-Grandfather" "In the marshy countryside outside dublin." "He made everything he needed himself, here." "He made it in a foundry that he set up" "At the bottom of the moat," "That was fueled by the turf from the local bogs," "By making the most of all the resources he had." "I think he wanted to see farther" "Than anyone else had ever been able to see before." "He invited great scientist s and astronomers" "From all over the world" "To show them what he saw here at birr," "And that was amazing at the time," "Because many other of the early astronomers" "Had guarded far more carefully," "And he didn't want to do that." "He wanted to share what he'd discovered with everyone." "Narrator:" "Today, a kindred spirit" "Pays a call on the earl of rosse's telescope." "Man:" "My name is francisco diego." "I am involved in optical design in university college, london," "And we are planning to build a new mirror for this telescope." "Narrator:" "The antique diego is restoring" "Worked the same way as newton's telescope." "Images from space were concentrated" "On a concave mirror." "In newton's day, the mirror was 5 inches wide" "S 200 years later, the earl'" "Was 6 feet in diameter." "Diego:" "With telescopes like galileo or newton," "You could only see the solar system" "I mean the moon, the sun, the planets," "And almost nothing else." "Earl of rosse:" "And you see here a plate" "Of the 6-Foot telescope with an observer" "Here in position." "remembering, of course, that this is a reflecting telescope" "So the observers had to get into position at the top" "To look right down the length of the tube" "To see the image reflected" "In the giant 6-Foot mirror at the bottom." "I was browsing in your library," "And found this book" "This is "transactions of the royal society,"" "1850 or something like that." "And there is the 3rd earl's" "Drawing of the whirlpool." "The whirlpool galaxy" "The first time the whirlpool galaxy was ever seen." "Narrator:" "Telescopes like the earl of rosse's" "Gave new detail to distant wisps of light," "Assumed to be strange gaseous clouds" "On the fringes of our galaxy" "The realization that these were indeed other galaxies" "Would only come after another conceptual breakthrough." "The universe was once again about to be redefined" "Now by light," "Born across time and the incomprehensible" "Distances of space." "Diego:" "Spectroscopy is the analysis of light." "The information that we get from starlight or from sunlight" "Or from light in general is tremendous, is enormous." "Narrator:" "It was a german physicist" "Who discovered spectroscopy in the early 19th century" "Joseph von frauenhofer." "Diego:" "He was an optical manufacturer." "He was working in a company which was building" "Lenses for astronomers." "He was very methodical." "He used to write everything he did." "And fortunately we have these texts" "Of his own very words" ""In a shuttered room i allowed sunlight to pass" ""Through a narrow opening in the shutters" ""Onto a prism." ""I found with the telescope almost countless" ""Strong and weak vertical line s crossing the spectrum," ""Which however are darker than the remaining part" ""Of the spectrum of the color image." "Some seem to be nearly completely black."" "He couldn't explain the origin of these lines." "He just saw that part of the spectrum was missing." "Narrator:" "In the cryptic traces of its light," "The universe reveals its true colors." "We can see its chemical structure." "Light is originated in atoms" "Light is originated" "Every time that electrons in these atoms" "It's emitting or absorbing light at a particular frequency." "So each chemical element has a particular way of behavior" "The electrons are jumping in particular places." "So depending on these places" "Is the position of the line in the spectrum." ""Ah, this is hydrogen."" "but if the line appears here" "So in the solar spectrum we have the finger prints" "Of a lot of chemical elements" "That we can identify in our labs," "Because with the same equipment we take a spectrum off our lamp," "Say, for example, an arc of iron" "And we can produce the same lines in our labs" "And we match the lines from the sun" "With the lines from the lamp in our laboratory," "And the match is perfect." "Hawking:" "Using spectroscopy it was found" "That the chemical content of our sun" "Was identical to that of any star in the universe." "Our sun, and our solar system itself," "Was just one of an infinite number of others." "Perhaps we ourselves" "Have no special place in the universe." "Diego:" "The chemistry of star s is more or less the same" "As the chemistry of the sun," "So the sun becomes a star or stars become suns." "This is a big revolution." "This is like a copernican revolution," "When you abandon the idea" "That the earth is the center of the universe," "And you say, well," "It's no longer the center of the universe no center at least of the solar system" "And that was a major revolution in science." "Now we have another revolution in which we say," "Well, we are not so special about it," "Because our own bodies, our own chemistry," "Our blood, our bones, our skins" "They are made of hydrogen, nitrogen, oxygen, etcetera" "Sodium, etcetera." "And we find hydrogen and oxygen, etcetera," "In nebulae, in stars, in the universe." "So it is the same chemistry," "So there is nothing special about it." "Narrator:" "Light, it turns out, is a messenger," "As swift as it is informative." "The news it bears is not just about chemistry." "It also signals the motion of the universe itself." "That discovery is owed in part to christian doppler." "Diego:" "The doppler shift has been, perhaps," "One of the tools in astrophysics, i would say in cosmology now" "Because it is our speedometer, if you like." "It is the meter that we us e to measure the speed" "Of almost everything in the universe." "Narrator:" "Doppler suggested that, as an object moves," "The light it emits will appear to be altered." "We can't observe this in everyday life," "Because light moves too fast , but we hear the same effect." "Sound is also carried in waves" ".As it approaches, sound is also carried in waves" "Its waves are squashed together." "As it departs, the sound waves are stretched apart." "The change in pitch is audible and known as the doppler shift" "By analyzing stars," "Scientists found the doppler shift at work" "In the light spectrum as well." "If a light source moves toward us," "The frauenhofer lines are shifted" "Towards the blue end of the spectrum." "If the light source is receding," "The lines shift towards the red." "Hawking:" "These extraordinary patterns in starlight" "Brought the dawn of a new age for cosmology." "It became possible to tell" "Not only what the universe was made of," "But also how it was moving" "The breakthrough came" "By analyzing light from deep in the universe" "Light seen through powerful new telescopes in america." "They could reveal" "Details of the universe never seen before." "Jastrow:" "Everybody knew what the milky way galaxy was" "A collection of billions of stars" "To which the sun belongs," "But nobody knew" "What these little patches of nebulous material" "That looked like spirals and pancakes and so on were." "And some people thought that the milky way galaxy" "Was the whole universe," "And these little spirals were wisps of gas in that universe." "The most famous person that worked at mount wilson" "Was edwin hubble," "Who came here when he was quite young, actually," "Right after his service in world war i," "And hubble had the golden touch." "He had a knack of picking the important problems." "Narrator:" "No problem seemed more puzzling" "Than the one posed by the earl of rosse" "And his contemporaries." "What were those strange swirls they'd sighted?" "Hubble wanted to know." "Jastrow:" "Making use of the extraordinary clarity" "Of the atmosphere over mount wilson," "Which is the best on the continent," "He was able to distinguish individual stars" "In these little clouds of gas, these so-Called nebulae," "And that told him in itself" "That they were not wisps of gas in our galaxy," "But galaxies in their own right," "Each one containing billions of stars," "And that the universe, the true universe," "Was populated with countless numbers" "Of island universes," "Each one like our milky way galaxy." "The distances that he measured" "Were absolutely stupefying to the astronomers of that time." "He found that the andromeda nebula," "Which is the closest galaxy to us like our own," "Was at least a million light years away," "And a light year is 6 trillion miles" "A very, very great distance," "Far outside the edge of our own milky way galaxy." "For the first time we knew how big the universe was" "With that discovery." "Narrator:" "Meanwhile, doppler's theory came into play" "Under the studied gaze of a colleague of hubble's" "Vesto slipher began to analyze light." "Jastrow:" "All of the galaxies that he could see around him" "Had red shifts," "Towards longer wav elengths." "And that would mean, of course, that relative to us," "They were moving away." "When slipher gave this report, everybody stood up and cheered" "They didn't know what it meant , but they had a gut feeling" "That it was something cosmic in its significance." "Narrator:" "That galaxies were speeding away from us" "Was a discovery as striking as it was baffling." "But unknown to slipher and hubble," "An explanation was being formed an obscure german physicist." "His new model of the universe would be no less radical than those of centuries past" "And among its predictions would be the revelation" "That the universe is rapidly expanding." "All the more remarkable was that this insight came" "From a man now working as a patent clerk" "Because he had shown so little academic promise" "His name Albert Einstein." "He was forced to learn" "A lot of very complicated mathematics in order to do so." "But in 1915 finally the theory was born." "The theory was called general relativity," "And it differed from the theory of gravity" "That had held sway up until then for more than 200 years," "Which was newtonian gravity." "All objects in the universe attract each o" "Einstein's theory of gravity is radically different," "In fact, that the objects don't" "Attract each other directly at all." "One object makes dents or dimples or warps" "In the fabric of space-Time itself," "And the other object, as it moves by, is actually bent by the curvature of space-Time" "By the fact that there's this dimple there." "And it looks like it's being attracted to the first object," "The object that's making the dimple," "But, in fact, it's not direct." "It's just reacting to the warpage of space-Time" "So one thing to understand about general relativity is that you can't have a whole collection of matter" "Say, of galaxies or stars," "Which are sitting in static configuration" "With respect to each other, and expect them to stay there." "They won't." "They are going to collapse in towards each other." "So this means" "That you can't have" "A static model of the universe in general relativity." "The model The universe either has to be expanding" "Or it has to be contracting" "It has to be dynamical in some way." "It can't p" "Narrator:" "Einstein imagine d that there must be" "Some unknown force keeping the cosmos" "From collapsing in on itself" "In fact, he had predicted that the universe is expanding" "Jastrow:" "The astronomers" "Looked at slipher's discovery of the motion of the galaxies," "And the prediction that the universe expands," "And they said, aha!" "These are two sides of one coin." "They fit together." "And hubble again with that golden touch" "S for working on the big problem" "Turned his attention to this question," "And he asked himself, how can i investigate it?" "And the way he did so was to start to measure" "The red shifts, as they are called" "The velocities with which" "These galaxies are moving away from us." "Narrator:" "Hubble began the painstaking process" "Of comparing the distance and redshifts" "Of dozens of galaxies." "The results were staggering." "Jastrow:" "And he found something known today as hubble's law," "Quite extraordinary, that the red shift" "Or the velocity of recession from us" "Is proportional to distance." "If a galaxy at this distance" "Is moving away from you at a certain speed," "A galaxy twice as far away will be guaranteed" "To be moving away from you at twice the speed." "Hubble actually changed" "The picture of the universe" "Because the ptolemaic picture was static," "And newton's picture" "Of the universe was static" "But hubble showed that the universe is dynamic" "Everything is moving away from everything else." "Greek astronomers thought Most of them, not all of them " "That the earth was the center of the universe" "Copernicus showed that that was not so," "And thought the sun was the center of the universe." "other later astronomers showed no, the sun was not the center of the universe" "But many of them thought" "That the center of our galaxy was the center of the universe" "Hubble showed that there is no center." "That was a tremendous scientific, theological," "And philosophical accomplishment." "E he showed that the universe as far as the telescope can se" "Is populated with countless numbers of island universes," "And there is no difference whatsoever." "There is no center." "The second implication in his finding was" "Well, to explain it," "Imagine that the picture of the expanding galaxies" "Moving away from us and one another" "Is a movie strip." "Now run that in reverse." "And all the galaxies going backward in time" "Come closer and closer together." "and finally they all meet together at one point" "Speaking loosely, because there is no one point," "There is no center in the universe." "They all come together in an infinitely dense and yet infinitely extended moment" "And beyond that, of infinite density," "One cannot go." "So that moment marks the beginning" "Or the birth of the universe" "And all of the things that we see around us" "Every star, every planet, every living thing on the earth and in the cosmos" "Owes its genesis to that moment you can call it the big bang" "But you can also call it with accuracy" "The moment of creation." "Narrator:" "Today, our expanding vision" "Is keeping pace with an expanding universe" "There are new revelations" "Of the big bang, of dark matter, of a strange breach of space" "What are called black ho" "A black hole is a gaping void in space" "That sucks in and devours anything that gets too near." "It becomes compact, massive, and therefore able to" "If it encounters something else" "Able to eat some more matter" "It becomes the eater of all things." "Narrator:" "Cosmologists are now" "Exploring a universe their predecessors" "Would hardly recognize." "Hawking:" "It seems that the kind of matter" "Of which we are made" "Constitutes only a small fraction" "Of the universe." "Over 90% is something we cannot even see" "Dark matter." "It sort of puts one in" "As a human being" "Into some perspective," "That the earth is not" "The center of the solar system" "We are not even made of particularly" "Common matter that's around," "Because most of it's dark matter." "Narrator:" "Gradually, the heavens are yielding" "Their secrets to us." "These photographs are from the orbiting telescope" "Named after hubble." "Hawking:" "From sitting at the center of the universe," "We now find ourselves orbiting an average-Sized sun," "Which is just one of millions of stars" "In our own milky way galaxy." "And our galaxy itself" "Is just one of billions of galaxies" "In a universe that is infinite and expanding." "But this is far from the end of a long history of inquiry" "Huge questions remain to be answered" "Before we can hope to have" "A complete picture of the universe we live in" "" To learn more about "Stephen Hawking's universe," "Visit pbs online at the internet address on your screen." "" " Captions by vitac:" "Burbank,Pittsburgh, Tampa and Washington, D.C. " ""Stephen Hawking's universe" was made possible" "By alfred p." "Sloan foundation, to enhance public understanding" "Of the role of science and technology," "The arthur vining davis foundations," "The corporation for public broadcasting," "And viewers like you." "Corporate funding is provided by amgen," "Unlocking the secrets of life through biotechnology." "At amgen, we produce medicines" "That improve people's lives today" "And bring hope for tomorrow."