« StarTalk Radio

Travels in Time

2009-07-13 | 🔗

Is time travel possible? Or has it already happened? Get ready to spend some time pondering time, because in this episode of StarTalk, host Neil deGrasse Tyson is joined by co-host J. Richard Gott, author of Time Travel in Einstein's Universe and an expert in exotic astrophysics. Join us as we explore time travel, black holes, and worm holes, and analyze some Hollywood time travel films in terms of their scientific accuracy. Rich enlightens us on the fact that time travel is mathematically possible, citing Einstein’s Theory of Special Relativity to explain the phenomenon. In fact, there’s some time travel going on in the recording studio when Rich explains that Neil is seeing him as he was 3 billionths of a second before…maybe solving the secret to looking younger? Next up on the space-time continuum is the question of whether gravity effects time travel. Rich tells us that on a planet like Mercury, whose gravitational pull from the Sun is so strong, time ticks slower. You’ll hear some discussion about the accuracy of the movie The Time Machine, and how building a time machine like they did, as long as it uses the mass of Jupiter, just may give us enough energy to travel forward in time to find out the results of the next election! Another way to travel through time may be to orbit a black hole, but Rich warns us against getting too close to the point of no return unless we want to be spaghettified. You’ll also hear a little about Hollywood’s take on time travel depicted in Back to the Future, as well as in Planet of the Apes, for which Rich suggests that the first clue that time travel had occurred should have been that the apes were speaking English. The episode gets even more interesting when Neil and Rich take phone calls from fans. They answer questions about the expansion of space, seeing back in time through modern telescopes, and how the fabric of space stretches faster than the speed of light. Investigate wormholes, curved spacetime, general relativity, and all that cosmic craziness. Even crazier, though, may be when Neil recalls a strange memory of being confused for Michael Jackson when he was a kid, sparking his curiosity about whether MJ could’ve traveled back in time to get his old nose back? Rich says that even though we can travel into the past, we can’t age in reverse. Ponder the Grandmother Paradox, and whether time travellers have the ability to change the past. Finally, a fan asks how the past, present, and future coincide with the continuum of time. Rich has plenty of answers, but we’ll leave you with his reference to Einstein: “time plays out like a movie.” So, to make the most of your movie, we encourage you to sit back, relax, and enjoy the show.

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This is an unofficial transcript meant for reference. Accuracy is not guaranteed.
Why would she polluting industries meetings with many questions to be answered now? More than ever, we find ourselves searching through those answers is the very fabric of space science and society are converging here for the first time to review the knowledge, the Greeks, the barrier between what is sometimes in what is merely pop culture is. This is starting to rouse astrophysicist doktor kneel to harass Thyssen Media Complex star, talk, welcome back startle, your host, astrophysicist Lithograph patient and my cosmos
Lynn, complex professional comedian is actually on the road right now. She's performing at the Pittsburgh Improv might catch her tonight. Do you happen to be an area and you also an actress than appears in Z, on the independent Phil Channel on Sunday night check it out you gotta link, Is homepage at Lynn Dash complex dot com that win with an e? again on your hosting yielded Grass Thyssen welcome back to start talk. In lieu of my charming co host linkup. I snatched from the halls of Princeton University and all time friend and colleague of mine, Professor J, Richard got Richard got welcome to start talk. Radio,
male De Villiers, Richard God, is one of the world's experts on all kinds of exotic astrophysics, and today's subject is going to be time. Travel is time travel possible and what sort of frontier astrophysical phenomena black holes warp space wormholes? What sort of astrophysical phenomena enable it or prevented? That's today show on startup now issued at that and rich. We every time when we begin start talk we find out what our good and bill. Believe I have to say about black holes in big bang in the universe. So can you can hang for the whole our chair and, let's see what bill my says, to start us off check him out Hey bill, nigh the science guy here, the singer, Hank Williams, pointed up we'll never get out of this world alive for us, conveyor belt of time goes one way and we're on no way to live forever
not a year forget it. Gravities got stuck but since STAR talk, radio. We can tell you there is a way of final, I called and followers that's a start. It was a star so massive that nothing can get out of your energy lightest along with everything else in there. End up in another part of the universe or another universe at another time, you're still dead boy, call businesses, not attitude, and we may have discovered, an intermediate bird and special? of interstellar gas called blobs detectable with accurate. Fundamentally from our universe. Is there a way to see some other side there to be a lot more to the story of stars, and we know right now start up Thus, the review- and I can't help it struggle and strive to understand the world and keeps us alive listener, that was built, I frenetic, as he is in every minute that he gives us you listening
are talk, radio. You can call us at one eight, seven, seven, five star talk if you have a question on the frontier of astrophysics, be it about Big Bang, the black hole we ve been discovering wormholes and in particular today, subject time travel so rich, my guest house for two riches is time travel possible. Well, yes, Einstein showed that time. Travel to the future was possible. In is ninety oh five theory of special relativity, and you say that as though you ve done it, it's possible like, like you, possibly go to Baltimore. You know. Well, we do not have time travellers with as even today, the greatest I'm traveller up to date is Sergei critical of
the russian astronaut. He spent time upon the mere space station in and in a few shuttle flights, not a mere space station, preceded the current international space station. Then sir, I hear people forgot, their dispute clue demand you and so the mechanism that issues in there is that an stand show that in special attention that moving clocks tick slowly. But what? How was he on mere while the two little time is spent in orbit was about eight hundred and three days. So here she spent years yeah, yeah and so that space station at the mere in orbit is going like eighteen thousand miles an hour, so does that fast enough to have measurable effects it slow? stand your clog just a little, so in fact, He he came back after all of his voyages. He was one Forty eight, the second young, than he would have benefited state all sadly travelled to the future one forty eight of a second one
forty, eight, the second. So when he got back see, he found the earth to be one. Forty, eight of a second towards the future. Now doesn't seem like much. No, not only does it seem like much isn't. Well ask me once, or was it so easy to travel in space, but so hard to travel in time? And answer is: we haven't been very far in space either the fathers we And its basis to the moon which Stan would tell us is one point three light seconds away: you need, I think it is calculated. You would need Einstein to tell you it's well. He would tell you that if you're gonna compared distances and space with this, this is in time. You should use the speed of light, so we say alpha toys for light years away. The nearest takes far too soon start, so it takes light for years to get here, so we ve been point three seconds in lights
against in space and forty one, forty eight, the second in time so, Mr Crane, off his light. Lindbergh he's like travelled a distance in time equal to going across the Atlantic. Grace. I say, okay, so that just the beginning then doesn't it step by the rich. You have a book called time travel in ice times. Universe get came out a couple years ago, bus available on paper, back ravaged by hope, Michelin, right and we'd like to actually give away some free copies of networks to callers whose questions may have earned the right to receive a free book will be listening for I pergola curricula curricula, Flickr, regular now the previous guy I now the previous guy, who had the rack and ruin surge Sergei of data, so the of a second. So apparently, it's gotta be named surgeon, silver, so we will how many americans- or in the running for this I guess
not in the running girl, so we're nicer to our people been leaving them in orbit for years and forgetting about them. I think that's right so you have like the soda layman's account for how you can actually travel into the future using Einstein's rules. What what is it about? The fish relativity that the US well we all know that Einstein was a genius. So what did he do that really made Emma Jane Swell Special one was motion is relative and you ve seen this when you're on airplane gone at five miles an hour in the windows are down you watch and some bad movie in, and it seems just like your on the ground down. If It seems just like your on the ground, in fact, it is not our that if there's no turning, there's no terrible is not turning in fact Sunday. Actually are on the move,
times lately. I well that that was it that its motion is relative. You can't tell whether you're moving or not. He thought that that applied to Newton's laws of physics, and he thought that should apply to all the laws of physics, including electronic Amex. This the study of properties of light, basically yet lighten articles interacting with India, yes, and so the second partial it was at the speed of light should always be observed by you alight beam should pass? You had always the same speed, three hundred thousand kilometers a second and now because Machel showed that the speed of light was could be calculus. From a ratio of magnetic to electric forces and when he got at velocity. He said: Eureka This is the velocity. Astronomers have already measure to be the velocity of lights, and I know that it's your magnetic waves, which I've does calculated light is lie, so Einstein thought that
see that always at that speed. If we didn't, we would know we were moving. If we saw by two hundred thousand kilometers Zheng was I'm goin? I must be moving at a hundred thousand say and that when the lad, but the first postulate so with to partial its improved, a lot of theorems that you could then check ready, did thought experiment so experiments that he thought of. Why do these as a fearest without a budget to create a lab? He thinks experiment, is out of the experiment. Nobody really done anything like this before he thought up an experiment in one of the experiments was, he said, because I have a light clock I just have a mare at the bottom and merit the top about, so I being back and forth the mere on the floor in a mirror on the ceiling. That's right start a beam of light mountain between the two and there it goes and it'll take. In a number of nanoseconds to go from the top to the bottom billionth of a second year of its three. Beat all your your clock.
Take three nanoseconds too too to be, but a foot per nanosecond. That's The alliance are easy to remember in those years, you're sitting now for me, three billion, so the light second away, three billion three billions of a second yes away, for me, in fact, your c and may not as I am now, but as I was three billion so the second ago, and you look marvellous, have a big younger than I really am the Father, you move away the younger you lot of kids so this is something you remember anyway, the yeah like clock and then turn This clause room- and I see the lightning just go back and forth, and I can count I can keep time this way. That's a good clock. Now suppose, there's an Ashura moving by you had forfeit, The speed of light arriving by shoot from left to right now
he's going to like like to just like yours- and he sees it going up and down in the light clock from the floor to the ceiling in his room in his room, but his room is moving relative. So when you look at his life being you see it, from the bottom down here over on the left to the upper right. At the moment, from left to right. By the time we get to the top he's move moved over to the right so that light beam has gone on a longer diagonal path. As far as your, We ve got on the high part news of that trying the high partners of the we all remember the high partner. We all remember that even in its longer than one of the sides. So what are you listening to professor Rich got from Princeton University, a colleague of mine from the Department of Astrophysics there talking talking cosmic stuff,
and we were he's explaining how you can move into the future using relativity so go on. So so, when I look at his light clock, his light clock has got to tick slow relative to man. He is moving at forfeit The speed of light that diagonal path is five feet that I measure. So I'm a say. It takes five nanoseconds for his talk. The clock to tick so I must see him his clock, taking it three fifths. The rate of my clock now. Here's the interesting part all of whose clogs have to take slower. By that same fact, anonymous is like clock now just like clog is hard has to beat slower. Otherwise he noticed that relative to his heart was is also a clock that he's like clock is ticking. Slow and so because You can't know whether is moving and not here, yes, the age more slowly to three saying Iceland's to postulates required that he's aging less if his put to populist are correct
LO and behold experiments show that, in fact, this is the case they do. They took time clocks on aeroplanes, for them least around the world where the velocity the plane would add to the rotation of the earth and they came slow by about fifty nanoseconds, which what Einstein would have put any hawser accurate enough to measure that when clearly you're a russian astronaut, you could not have at our last check your heart beats. If it's one fortieth of a second to slow, you couldn't have done that. That's really the calculation that tells you that he went into the future by that much, but they apple occasions. This large, because if you, who get on a spaceship and you ninety nine point: nine and five percent the speed of light and to the south. Our five hundred light years away and you turn around and you come back when you get back the earth. We'll be a thousand years older, but you will have all aged ten years. This is how you move into the future. Now huh
to do that, as everyone will just forgotten about I think that we really interesting new. Now you would do this. Well, we love you here in the present bridge, but the year three things. It would be really ok, We would hope you get from earth is still here if nothing else out here, it's Marco Polo twenty four years to go visit Chan and come back to Europe and tell people about it, and so if you went on accelerating rocket ship, you could accelerate at one g acceleration comfortable it take about twenty four years gone out and back on your as far you're clog was concern. You drive back there, be a thousand years in the future. What we're gonna get back. That's because we know that had been movies. We ve all seen that involve time travel and I want to get from you your expert view on whether those movies got it right or wrong, or what that was fun or what was what? What irked, when you, when you saw them we're gonna, take a break from stir, talk, radio, Neil, the grass Thyssen, your host and calling
and tell us what your favorite time travel movie has been or whether you want to travel into the past or the future. If you had that choice, learn how to travel into the past as well and learn all about what kinds of paradoxes that might create, as we ve learned from films as well, we'll be back after a break one: eight, seven: seven: five, our task is our number pay start up fans on March. Twenty fifth start: live is back we're returning to the historic Count basis centre for the arts in Red Bank, New Jersey and tickets are on sale when right. Our talk, radio dot nets, last tickets to grab your tickets before they're gone now. Some of you may be wondering why the one the only Chuck nice be at this star talk. You may be wondering why the one the only Chuck nice be at this star talk live
will. Sadly, the answer is no, I seem to have lost myself into a recording studio and have been stuck here for about three weeks have now come to the conclusion that this money home- that's right, I live here now, so I won't be there, but neither will have some other fantastic comic co host along with some very special guess. Bring the universe down to So once again visit STAR talk, radio, dot, net slashed tickets to get your seats now and we'll see you at the show. Well, I won't see you at the show, because I live here now. What's your startup fans chuck nice here? Do you love listening to start well. Have you ever listened to start talk? lie. If you have, it even if you have it your lucky day, because on March twenty four star talk, light is returning to the historic Count basis centre for
the arts in Red Bank, New Jersey and tickets, our own sale right now joined meal. The grass hastened his comical hers and special guess. As they bring the universe down to earth visit, STAR talk, radio dot nets last tickets to grab your seats before those shows cells out that start talk: radio, dot, net, slash tickets,
you're a space, Cadet rocket scientist I want to hear from you. The phone lines are open call. Now this is starting. Now they want a seven seven. Five startup did you have a question about time, travel wondering whether it possible. We have a question for my host, my co host for today's food and he is professor J. Richard got from Princeton Universities, professor of astrophysical. There is written a book called time travel Einstein's universe, so we're all about that today? But first, let me ask you: if you had some Princeton, I noticed you have a distinct sent from south of the Mason Dixon Line, but beware that from I'm from level
in fact, in regional and local level, in many different ways for bananas movable contains how many other Kentucky astrophysicist are there I well Hobo actually spend a little time. It had been available. Teaching teach high school, but he surely and discourage, did not speak with the Kentucky accident. No, we have had an anglo Saxon after spent some time and Ngos. So my he'd leg enjoyed fake, amounting to access max and hasn't changed in Jersey. Might remember, the prisoners were Einstein spent out his later years. He came to America and hung out at Princeton. They still revered there. Of course right is that right, oh sure, at the fiftieth what we had the fiftieth anniversary of his nineteen o five theory, especially relevant today, and they actually put up a bust of Einstein in May on the off the main street there in Brandt's. Ok do people genuflect in for
did they present people love than he would eat at the restaurants, and he would he would go? the flower shop in order like seventeen roses were now, and it's always girlfriends. I heard he was the ladies man, as it were, We did order. You didn't order. Flowers of the flower shop in the trouble is that that no, what cashes checks, because of checks on vines that was worth more than the amount so finally said. Listen. I could I clear up my checkbook I'll, give you as many autographs as you wanted to just catch Stein. T shirts of other soon will be like Richard got t shirts and prince anything. Why I'm saying one yet so rich, Tommy the knot we can you time oh by moving fast out of Einstein's theories, general theme, relativity gravity. Extreme gravity can also affect your time. Travel. That's that's you!
whilst many examples of that that you can cite well, if you, if you go deepening, gravitational well does closer to a source of great closer to the source of gravity, four eggs. Apple? If Europe, the planet? Mercury, your clock would take slightly slower they're, both because mercury is orbiting around the sun really rapidly more rapidly than the earth, but also because mercury is down hunkered down in the gravitational well of the sun. So when photons come out from mercury to us. They are They lose energy because it to climb out of this gravitational well, in that light, since their wavelength and it means that they come there. The ways come in from way like the wavelength more slowly, so you see everything going in slow motion like so I'm talking to you very slowly from me.
Had hasn't if you were a mercury resident and didn't vaporize in the heat of the sun, that's what you like a little slowly! So if we sent an astronaut to live on mercury thirty years and then brought him back to earth they come about. About twenty two seconds younger than they The ban. Are they travelled twenty two seconds into the future so ignoring the speed version of that time. Travel just the b. In a deep gravity while he can just sit there and age more slowly? That's Turks, movie that sort of captures that aspect of it? Well? Yes, there is a movie, the time machine and two thousand and one where it reached you,
Sometimes she gets the same story of age, anyone basic when few additions or many lives, and he sits in this sort of spherical time machine and he just notices that the the world outside is going by rather quickly and namely he's going slowly through time, he's age more slowly. Naked really build one like this about that size, its depicted in the movie, if you put yourself inside a shell of mass. It was about the mass of Jupiter. Now the age four times more slowly than the people ads. So it's a good way to hurry to the next election. You could get their quicker now one year instead of four years. Yet only thank you one here to get there, so that's just Jupiter, but you can imagine a black hole, would accelerate this right. Well, yes, the. If you wanted to go millions years into the future, is the movie portrays in going eight hundred thousand years into the future for Thou and you need it?
a hundred million solar masses and it's gonna be about the site. The shell of mass is going to be about the size of the earth Orbit and you're gonna sit in their age more slowly and the other way, and by the way, it's one thing to say your age more slowly, but which actually going on as you think you do, you're being normal and everything Don't you is moving faster, that's right! and one of them got a phone call where I think we have Michael on a line from LOS Angeles does that you how you know welcome to star talk, at the you? So to answer my question, I get if you are on mercury, your body gonna have to expend more energy, and I e that you know party bodies, gonna break down if you are on mercury, your body gonna have to expand more energy, and I e that you know part you bodies, gonna, break down faster muscles and all about. I would think basically, while obviously got mercury are, but I'm even I get them thing. How do you counteract that physical
that would be detrimental to your body, plus there's a little bit about the fact that the sun would vaporize you on the service of her. I write I get that its. Is it the gravity that actually yet does this or their yellow, like Einstein, said the fabric of that universe and stuff? Being struck! Michael, is an excellent question, so rich when you, what he's asking is like this? They can. Thank you, Michael. What he's asking? Is it something physiological about the heavier gravity that your bodies reacting to, or is it something deeper than that Well, you think everything's going normally we're gonna put in a good space cabin to live war, where we're going to protect you from the heat of the sun and in that. But the the The thing that's gonna happen to you is that as you live at your life, if you signals out to me those those are gonna lose energy as they come out. So
their wavelength is gonna be longer. So I'm gonna, look at you and see everything happening in slow motion and you're gonna, look back at the earth and see we're thing happened in a bit fast, so the the time travel movie that we were talking about. Where are you saying, Thoust the years go by on the surface of the earth and he was agent only very slowly. Those, though a visible photons coming in showing him the visible I come in here would be shifted away into the ultra violet and into the x rays. So so he Be fried by looking at the senator. They are they miss that part of the movie they mess that part and also the part that is spaceship, would have been so massive that it would have torn the earth apart. So I do not expect to find people building tat machines and there are no have you ever have you ever consulted on a time machine movie? I'm not your author of time, travelling Einstein, universe
solving on other movies and end, and the thing is they they use as for your advice and then they don't follow because the plot needs to be spicy, that's the trouble so tell me about how black holes would play into this. I if I were but a black hole, real close. I can we moving fast and I'm in a deep gravitational. Well, so how different the time there were, you can slow down your clock by badges hanging out in the vicinity of the black or don't go in. Towards the that point of no return you you, you hang out outside and you can. You can get quite a bit towards the future doing That's, so that's a good way to go towards the future. You wanna get a big black hole, so the The title forces are too bad. You be ripped apart. You don't want a part, but we got rebellion solar mass black holes for the title forces at the age of five.
We ve got those in the centres of galaxies, so we get injured air and report back there hang around Europe mean a talk radio on your house, Neil De Grass, Thyssen with my guest cohorts this week, Professor J Richard got the third. If I remember correctly, professor astrophysics at Princeton Universities telling us about time travel the astrophysics of it. You can call me if you have a question about black holes, the universe, the Big Bang ways of travelling for two backwards in time, one eight, seven, seven, five star talk. You can also hear streamed start talking video dot net or you can tweets us. We have a tweet, send it to start talk radio where there so rich, the this other movies, where they go, save your common fro, black holiday stretched out. We need to use, we get one like that. They come in for a while ago, who very slow
one from the future from the barrier between us and will know by the frequency of your sound, tell me about everyone's early favorite time travel which was planted. The apes, such as a simple time travel into the that's the simplest kind, the Ashraf Charlton Heston he goes. Spaceship. You know it gets! I went to fast near the speed of wide. He didn't really know that he comes Maggie lands on the earth, If you it's know, what's he thinks it's just landed on another planet, Aziz, apes, running everything and then, of course it give away, then the movie body, but one which would have killed a man, is that the extra speaking english Finally, will pick up You know why using the apes we know, Buddy buddy. Finally, the end of the movie. He he encountered the ruins of the statue of liberty and then he says my sergeant
both forward time travel using easy. Today we know you can do. This is just a matter of money You got to increase and ass a budget while also you get. We ve got another. John. Is that you and allay? Yes, it is doing what Cressingham for us today. I have a question which has trebled me for a long time, and I am hoping that somebody can answer it. You're not going to us. I understand the universe to have at the time of the Big bang, then a very, very tiny point, and then we had the big Bang and hence the big bang. According to modern times, I believe, thirteen point seven billion years. You got it and with modern telescopes? we are able to see probably more than ninety percent back in time to
galaxies it around the very edge of practically at the edge of the universe you gotta, those galaxies are perhaps thirteen billion light here. The way you can teach Astro One alone at the rate you're going sir. It's not like you will have any question at all at the end of this. My questions, starting from a ploy in thirteen. How did those galaxies- thirteen billion light years away in approximately thirteen thirteen light years away so quickly. Which was always ask, as is a very good and very deep class, and is their time travel going on with these galaxies. What the fuck you John for that question, rich, what you have Its main here is it in the very early universe, the though galaxies, are moving apart from each other because space between the galaxies stretching like
big sheet of rubber and so We see the galaxies the time getting farther and farther away from us, because the sheet of rubber is stretching so at the beginning of the universe. The universe is stretching so fast that the light can't travel between. The two points, so the law, the the spaces stretching between those two galaxies faster than like across the distance between them answered. In theory says you can't go faster than the speed of light. Someone can pass you faster than those be light, but never says it's a space between you and someone else can stretch faster. The speed of light, so that's how they get out there for us, too, the return of the fabric of the universe, expanding at what any arbitrary speed clouds dry, the tenets of the bill, that'll pieces avatar just stretching a little, but you put a lot of them together and that makes the distance between the two stretch faster than the speed of light, while already
are given away your book. Actually, if I want give it to John, but you hung up before we could get his address back. If he calls back, I think we can give us a dress. I think we'll give him a book cuz. That was a good question That was a great Johnny throughout their. Let us know I will take a break and we're gonna come back to start talk. Radio, if you want to call us you ve ever question a comment about what your favorite time travel movie is a question for my co host for this episode. J Richard got professor of astrophysics give us a call at one, eight, seven, seven, five start off we're streamed down. Our talk, radio dot net and you can treat us at start. Talk, radio,
see in a bit the future of space and the secrets of our planet reveal. This start. I welcome back to start on new threat facing astrophysical with a friend and colleague, Professor David forgot, professor, after possessed oppressed in universities as yes, it covers substituting for inland complements, was actually doing stand up our economy tonight at the organ project or atmosphere so rich couple a question for you all for your students get smarter dumber. Lately we hear all these complaints about America getting them when you teach Ashraf, how do you feel about over the years People today are just as smart as they were before
at the same time, it has been like an Einstein in your class that you could identify somebody. Will they come along? More rarely oak, I'm just curious. You know I mean you know you I used to be in and in the end the professor all, but I now I don't see a new crop of students every year, but if this trend lies about stable, that's that's a good sign. I think so. Let me ask you when we talk about time, travel and not to be two topical, but we lost Michael Jackson. Maybe he and I are the same age by the way. I don't, if you know, but he and I were once confused for each other back when I was thirteen years old That's it. I was. Less sort of beefed up back than before I sort started doing athletics. I was kind of a skinny kid, and here we are the same, the skin tone, and that the same afro of the day and three girls who I was and a growth in a gimbals, the deep
store any three girls like drawing straws, as he would walk up to me to see if I was Michael Jackson and one of them came up and I have to disappoint them. You must look very self confident and certainly before all the surgery, I wonder- It is one thing that central body for it and back in time it could, like Michael Jackson, get his old. Those back or something of their way to do something like that. Well, No, when you, when you the time traveller, even though you go visit the past and you're, always going forward into the future into your own personal into your own personal future, so you keep aging it's like Magellan in general activity. We have curve space time, so Magellan, crew left Europe, they went West West last around the world. I came back to Europe began, so the time traveller goes far word always toward the future as far as he is concerned, but Sir back through twisted curved space time like a certain over the earth was to dislike.
Serves theirs was true enough and in his own past. So you can vote. The past but you'll be older. When you get back there, you pushed your nose and everything else that Michael Jackson, wanted bad mood old age in reverse. When you go back out now about wormholes. We always heard about you know in contact. Jody foster looks like he travels through a wormhole there's the warp space in STAR Trek for let's go back in time, How is that possible? Well, in general relativity, this is an stance theory of curved space time to explain gravity, and we believe this because been checked by light bending around the sun. We done experiments and check. That means we know it. We don't have to just believe that's right with the experimental ten so general activity. Have curves space time. So there was a fake. This poor. There was young lady name bright. She travelled far faster than light. She left one day in a relative way and returned home the previous night. Ok there she
so We always knew that if you could go faster than the speed of light, somehow you could go by in time theoretical, but backward sooner market right. That's right would hit the back end in Iraq and so you'd know you're removing than the speed of why that's, because if you Iraq or the new shot, a laser beam toward the front of the rock and it would never catch up to the front of the river go backwards sooner market right. That's right. You would hit the back end in Iraq and in so you'd know you removing and that's not allowed, but at first partial and so build a rocket the goes fast in the spotlight, but if you can take a short cut by John through a wormhole and get to it, place in space effectively. Stir them like when a beetle I been there is that what they didn't start for arms we're just to remind you that the current STAR Trek movie out I saw it and I loved it star for was the save the whales movie, remember that once they go back to nineteen eighty four because
There's a whale sound in their future time and the aliens picked it up and they're waiting for the whale to reply and the no whales left, because we hunted them to extinction, and so there is a problem. There's a album, and so they did, of course was they went back in time. They got away. They brought it to the twenty third. So much to the whale surprise in the whale answers that extra terrestrial we're gonna bring to Wales to or they brought to but anyway it answered the extraterrestrial with it with a whale you know well, and so everything was fine, a theory that movie was always that the trouble started when Carl Sagan sent on one of the voyage, your spacecraft, a record with everyone on earth. Saying hello, oh line all the different languages. They said the whale saw this The big mistake, because we don't know
the whales are saying we know what each of ourselves or saying, even in our multiple languages. But what are you worried about this? It's just a while they may say help the humans are staging common savers which big was the basic blood of this movement, so they they went to the past. They got the whales and everything was fine. This is totally self consistent, ok, right and so that so that movie was was ok that one made they didn't write but the way I was a little surprised to be yanked out of the present and you have a whale, it disappears from San Francisco one day and they say where the we'll go and that's about it, that's about it. That's ok, so could it be that there are people who have just disappeared? That sort of open this is in police log, that you think someone has zapped them into the like Jimmy Hoffa.
No one can find Jimmy Hoffa easy in the future. Maybe they should be like a farm in the twenty first century is in charge the twenty third censured by a good place to do so. Do they exist. Can we make it wasn't me I gotta give out the phone number here. Could I can't be the only one wondering how to ask questions about this? You listen instead, talk. I'm your host near the grass Thyssen got a question for my co host for this session J Richard got professor of astrophysics. Spur on everything cosmic, but especially on time travel author of time, travelling Einstein universe. Give us a call at one eight, seven, seven five star talk so tell me that is, is what in time, travel wormholes. Can we make a wormhole? Well the worm always made you have. I have something to profit open or else it will collapse like a black hole and kill you. So we need some neg
If energy density stuff some stuff, they ways less than zero to hold. It open Gravity would hold a closed, that's really something to fight gravity needs and to fight gravity, and hold it open and and in fact, the empty space between two parallel metal plates is stuff: that way. The vacuum between those two plates is ways less than zero sky, the chasm, Arafat and still less so, we notice that exist. Yeah! That's what kept forges into prop open. They, the wormhole and allow you to go through. Also, ok, but you gotta keep it open Eliza collapses. Onion you're, dead. Yeah dangerous, studying in in one mouth of it is like here near the earth and the other one might be for light years away. So you you jump in the wormhole. You travel about ten feet new pop out near alpha's entire that works at that
works area in you, you, you then have beaten alight beam there, and so, if you move the warm all miles around appropriately, you can build a time machine. The call another one, John for Tucson, Tucson Arizona, John, no captain a point of use! Tuscan! Tuscan! Cuff! Excuse me! So you got a question for Professor God, only about curves material, Tony and then having any absolute motion wooden rotary motion. We affirm our motion if you're, like blindfolded in favour. As I get back, some start, spending in a circle wouldn't be effect. The arms were now wouldn't proved you to do that. You're moving without any outside employment. Excellent question, John, that that that's true You can tell whether not your rotating, not because you get dizzy, you know throw an end, and we have the thing in the inner ear to tell you that
and stands was, is relativity assume uniform motion in a straight direction without turning so that's the when it when you write the details of his possible, it is stated that way. So, therefore, if circular motion rotational motion, if you're in a spin drier, you Know- and that's that doesn't count in this analogy, you could use a spin dryer. You know if you'd Hopton, one of those your spinning around rapidly time travel to the future, not much. To spend dry or the same effect as being so. In other words, if you're to spin DR spinning really fast. Does that stimulate, b in a strong gravitational field. Yes, it does in fact Einstein show that those two things are really the same, acceleration you get on on the unwanted those whirligigs at the amusement Pardon warrior repress back hard against the back. He said
That's all gravity is that kind of thing. It's the same physical thing going on. That was his genius and general dimity. Ok, so Uncle John. If you still want to line, but that's so we have the correspondence. Tween, rotary motion and gravity and you can still age eight more slowly either. On a black hole or in a spin drier. That's what you're took particles go around and our accelerators they're going around in a circle and age, much more slowly as are going near the speed of light. So Richard gotta tweet, then ok thanks gone for calling in if you hang on will give it was, will get your book to you if you can give us your your dress before you hang up. If you're gonna, pull back and will give you will give you one of rich got the book at times. When I unit we have a tweet rich. Let me read it if you go back in time and change, something involving yourself. Would you remember telling you something not remember you being back in time, so you see what that means. It would
front approach, a paradox here. Other paradoxes, for example, Bill intends excellent adventure, there's a movie ever a dollar bill and tat you gonna, who remember I remain I just I just Netflix just last week in all family sought. They go back in time, collect these old historic due to bring an end to the present, but they also meet themselves at a point back in time sounds like that's a paradox or something could support. They prevented their parents for meeting for example, then they wouldn't be born, and then they couldn't go back in time to prevent the parents were meeting. How does it work well? this is the basically year your grandmother paradigm exposure kill your grandmother's, a young girl. Yes, as I go back in time, then you won't be born, but the travel and alive to go back and kill my grandmother to prevent me from being born. That's right, but if you If you kill your grandmother and then
you're you're not born, then your whole world line your whole path through space and time vanishes and you're not there to kill a grandmother, she's azure right after all, so that in really solve the paradox, I don't have to tell a ok, ok, so the there are two solutions to the paradox: one is that the world has to be self consistent tie travellers, don't change the past at all. They are always part of it. Like the person tweeting and said If you met yourself in the past, you have a recollection of that. You read down in your diary and so you're, not the time traveler's. What you're telling me rich rich line all I know my past. That's I know, therefore, that I will not build a time machine and meet myself in my current past, because that hasn't and in my past that's right. So
for known alive today? Unless they can tell you, they ve met themselves in the past, has met themselves in the past or will in the future, meet themselves in the past of the present. That's her That's it then meantime, travellers can inflict make phone number again. If you, if you post, we gotta, take a quick break. You wanted the question about time travel any these movies. We ve been talking about relativity. Give us a call on STAR talk: radio, one, eighth, seven five star talk, Tweet s at start, talk, radio, we'll be back breathing space and sat down to earth, you're listening to start
Welcome back to start off your hosting the autograph fashion, with a special guest have sitting in Berlin Complex this week is Professor Richard got the third professor of Astrophysics at Princeton University colleague of mine. From from years I spent on the faculty there and he's not only an expert on all things cosmic, but very particular expert. Time travel having written a book called time, travelling, Einstein's universe, and we like to give the book away two cars that we take online here, so so rich. That tell me something this: this, if you go back in time this this paradox problem. If you can't kill year, we prevent your parents for meeting. If I know since my parents did me and I was born, I can't go back in time and prevent Now so, therefore, if I'm gonna go back in time, it has to be in a timely,
That is yet to be invented, and I go back in time of the past of that, but not in the past of my card. One at once. One of the things we ve discovered is you are saying is that you can't go back before the time machine was invented. Of we invent a time machine in the year three thousand by twisting space and time up there we came, Did you come back to the present we get used to go from three thousand? the two back to three thousand and one, but not before three thousand, when the time machine was invented. If a time machine has not yet been invented, nobody's going back to visit Julius Caesar, that's right there, why you don't see it sufficient to explain why you don't see time travellers at that many assassination or other historical events like the Titanic. Well, yes, if you had a time machine any any built it before the gigantic. Had sailed, then you could use it in and
one wag suggested that the real reason the titanic sank was all the time travellers stowaways on board that added to the way it sag because of the time travellers there to witness the thing is we got a call from allay that you underline yes, hello. I welcome Mr Talk delighted. It's wonderful conversation My question for your guess for both to you is this we're talking a lot? time and time travel, I think many of us human beings experienced time as having a past where there are no possibilities of vivid thing which we call the present and then a future where there are no facts. Ok, in other words there their different paths present future. As I experience it how'd you reconcile that kind of time with
the time you're talking about with people aging at different rates and so forth. Its actual question certainly worthy of a book. I'd love so rich after we got this past present and future, which we experienced differently, physiologically or neurologically. Yet word you're talking about this whole continuum time. How did how do these square with each other? well. I stand showed that time there was a man assign associated with the dimension of time. We have high with the depth and time, and it had a minus that just had a man is innocent patients. That's all it is by, and yet there are human perception of it is like time is like a movie now. The path we know about, because light beams go forward in time, and there is an error of time that we think is connected with some of the initial conditions. The universe and light beams go forward in time not backwards. So
of events, something causes something over here and then the effects occur later. So that's why we know about the past and not about the future, whereas we can know where we came from and we were going because you can see the block that you walk in the block you're about to walk, but we will have access to I'm dimension of all this. We don't have access to the future yet, but the future in Einstein's view it was one four dimensional thing, so there was one passed in one. Future. We do have ideas now about many worlds. Theory of quantum mechanics agree many parallel worlds, but that's this view was that there was, this one for dimensional thing space time and played out like a movie? Ok, so when the two very popular movies back to the future and terminator they're both going into the past and in those these they had to. How did they square in terms of the astrophysics? in the back to the future movie.
At one point, when he stops his prayers for meeting, I his hand disappears when will hands just don't disappear like that and besides his whole, his home, a path through space time, Lloyd, disappeared, so they didn't quite solve that problem He did get his parents successfully back together. What one of my favorite lines is there? There is the the the estate where his homes were built. I think it was at the beginning. It was twin pines estate, but The pine trees got knocked over when they Delorean landed in that undeveloped land knocked over one of the pine tree so late around it becomes loan pine estate. So they are working in the many miles with extra theirs alone: Pine shopping center. That's what it was yet, Mozilla is so there their work and on the idea that there are many parallel whirls and they, when he goes back in time, he causes a branch off fond of parallel were separate universe which otherwise,
Daniel, except for these details, right interesting and terminator, so they that that when we left terminator, he gonna love terms Why? Yes, the terminator came back to try to kill MRS Connor, so she wouldn't give birth to John Connor, who is the leader of the human revolution to fight back against the machines who turns out to be the father of the guy who was sent back to that that got really kinda guy went back, turned out to be John Connor's father. That was very convincing. Richard we're almost at a time as the license plate of the professor in and back to the future? His wants its weaknesses. Megan forget how did you forget, as my uncle s name, so
Let me let me, let me tell you this. This has been a great show. Rich swimming gone back in time, it's nice to know that may be possible one day. It's not possible yet, and we're not gonna, be all a visit, major historical events in anybody's past right now, unless, of course, the government has a secret times but I've spent some time in a government there. No nearly did not nearly as competent. Has anyone ever calls them for breathing any any final reflections on on this Lisbon nice time here really is well. Thank you rich. You ve been listening to start on a radio programmes funded by the National Science Foundation? You can like us and STAR talk radio dot net where you can hear past shows and get the schedule for a commission. Is there you have it check this out We, when we complex returns, reminder tonight. She's performing lies at the Pittsburgh Improv Pittsburgh Pennsylvania we'll see you next week.
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Transcript generated on 2020-02-25.