A Cosmic Conversation with Kip Thorne

Welcome to Star Talk. Your place in the universe where science and pop culture collide. Star Talk begins right now.

This is StarTalk. I'm your host, Neil deGrasse Tyson, your personal astrophysicist. And today, we're featuring one of our one-on-one conversations, this time with Professor of Theoretical Physics, Kip Thorne. Kip Thorne, welcome to StarTalk. A pleasure to be with you, Neil. Oh, my gosh. We are coming from your home office in Pasadena, California. The wonderful office.

son designed this part of the house and built it. And my brother designed and built all the furniture. These are really useful people to have in the family. It's a wonderful family.

They're the practical ones. I've actually known you for some time, not that we were beer drinking buddies, but I think we've drank beers all together in the Canary Islands. Yes, we did. OK, OK. I stand corrected. But my first exposure to you was you were one of the three authors of this book called Gravitation. And we used to joke, of course, it was the only book where you learned about it just by carrying it around.

And I think we probably wrote it before you were born. You possibly, possibly, although I'm older than you might think. This book is a graduate-level treatise on basically Einstein's general theory of relativity. At the time I acquired the paperback of it, which this is, it's tough making a paperback that is thick.

But this has the exact proportions of what was then the Manhattan Yellow Pages. So we used to call it the phone book, just affectionately, may I add. It was brilliantly conceived because I don't know if you can notice on camera, there are tabs or different colors, it's white and black, and they represent two different paths through the book.

one is sort of the elementary path and one the more advanced path, except it all looked advanced to me at the time. So whose idea was this to come up with this book?

Coming up with a book, I think it was sort of grew out of discussions that Charlie Misner, John Wheeler, my PhD advisor, and I had a few years after I got my PhD. Those are the three co-authors there. And so it grew organically. That's the best kind of projects to have. In the 1960s and early 1970s. Yes, I was born before the 60s. Oh, briefly.

So, on here is Charlie Mizner, who was at the University of Maryland. And so my copy of this, I had you sign it. And then I spent a year teaching at the University of Maryland. So I quickly went over to his office and had him sign it. But before then, I started out in graduate school at the University of Texas.

where John Archibald Wheeler stole him from Princeton, I think is what that, or lured him from Princeton, I think. No, that's inaccurate. And so I had all three of them sign it. In fact, John Wheeler's course that he taught in general relativity is where I met my wife.

She has a PhD in mathematical physics, so we met in relativity class. That's what I'd say that. Very romantic place to meet. Very romantic. And John Wheeler used to give out a penny if you caught an error that he committed on the front board. So I have one of his pennies. I don't remember. It was not a big thing. It was like it was a typo or something. It was the right, the written version of a typo.

Anyhow, it's just the light to meet again with you. What prompted this was you have a lot of accolades, of course, including Nobel Prize. More importantly than that, you were science advisor on the film Interstellar.

I was more than science advice. Yes, you were. You were executive producer. I was more than a executive producer. It grew out of a treatment that Linda hopes the next girlfriend of mine. Oh, and I was a producer of sci-fi films. Yeah, and big producer of films of a wide variety, but Linda and I

dated in 1979-80, and she was too high-strung for me and I was too nerdy for her, but we became close friends. Why? Why didn't I know this? Why didn't we—where would one learn this? We need a gossip—a physicist gossip column, is that right?

It was some years later, after Carl Sagan, who set us up on a blind date, by the way. That's how we met. Some years later, Linda called me up and said, would you like to brainstorm with me for a movie? Wow. And we did, and that's how Interstellar was born. So was that at the time? It really was the creation of the Nolan brothers, because they took what we had given them.

uh which was basically a structure uh and a venue for the movie the warp side of the universe uh and they ran with it and changed our story almost completely and made it into a great film i don't know but all the seeds came out of linda and me

It's at the time, I mean, your professor at Caltech, the Richard Feynman professor at Caltech, now Emeritus, Caltech is a pretty high level place. How was it viewed for you to say, guys, hold on, I'm going to make a movie now. How does that received by your colleagues?

I think they were all enthusiastic. Caltech is a different kind of a place than some other more stuffy university. Oh, OK. OK. I didn't hung out much at Caltech. I couldn't judge the mood or their tone.

Yeah, no, look, we're on the edge of Hollywood. The Hollywood folks come over and, you know, Big Bang Theory was based on Caltech. Right, they didn't call it Caltech. What did they call it? They did call it Caltech in the first few episodes. Okay. And then they stopped using the Caltech name because the shirts that that's Hollywood speak for the attorneys.

Oh, that's stiff shirts, yes. The shirts got scared that they might do something on a screen that the Caltech shirts wouldn't like and the Caltech shirts might suit the Hollywood shirts. So they stopped using Caltech name.

And in the film, which I adored, what was it called, Real Genius? Real Genius. They were at Pacific Tech, all right? That was the real, the smart kids were. So of course, Pasadena is in like, I can't say foothills of Hollywood, but you have a proximal awareness of this huge industry. And you know that science fiction matters as a genre.

Well, and some of us love it. I love it. I'm signed up every time. And so, Interstellar, I think it introduced many people to authentic gravitational physics for the very first time. Well, Interstellar was unlike almost any other film. I think there were precursors in 2001 and in contact.

Carl Sagan's contact. Carl Sagan's contact. And the point is that science, lots of science was baked into that film from the very beginning because of the way it was born and because of the close, close collaboration I had with the Nolan brothers.

and built in right from the very beginning. And a science in which the guideline that we worked from is that nothing in the movie would violate well-established physical laws and all the wild things would at least spring from science in some manner. Any good science fiction story should be, but there's not enough.

Well, there's nothing wrong with fantasy films. The Harry Potter style, for example. It's just a different genre. By the way, that film, you must have known, you said, okay, we're gonna have to help people out. Give a guy a break, okay? They're trying to see the movie, they're trying to follow what's going on. What the hell's happening? Why did the guy get old? Who, why is he younger than his mother? What's going on? And you up and said, let's help.

Let's help a person out. Well, I would put it a little differently. I saw it as a superb opportunity to use this film as a motivator to get people interested or intrigued in science. Then there would be a bridge to science through this book.

Admit it, you created a gateway film. It was a gateway film. So the science of Interstellar, New York Times bestseller, Kip Thorne, with a forward written by, of course, Christopher Nolan. And it says, spoiler alert, this book explains the fantastic climax and ending of Interstellar. And so let me tell you how this issue came about.

Chris said to me early on, I would like Chris Nolan. Chris Nolan. I would like to make a film where the ending is as mysterious as the ending of 2001, a space odyssey. That's a high bar. That's a high bar, but he greatly admires Stanley Kubrick and that film.

And so, somewhat later on, as we were talking about the ending, and we had lots of conversations about the ending, he said, well, you can explain the ending in this book that you're planning to write.

So he volunteered you to write the books. Well, no, I was already planning to write the book, but he identified that as the place where the enemy will get explained. He was not going to explain the enemy. He would leave it mysterious in his film. He was pulling a Kubrick on us. In fact, we interviewed.

Christopher Nolan, if you're an archive diver, we've got a whole episode with Christopher Nolan, even before Interstellar was produced. And as we know, so many of his movies, he plays with time in some kind of interesting way. If I remember correctly, he talks about how influential 2001 Space Odyssey was to him back in 1968, that would have been. So let me ask you just a couple of things about the storyline.

And I have an issue with it, if I may. I don't know if I ever went public on this, but I figure I'm in front of the man himself. So if I have an issue, they would be here right now. You're going to get turned into a journalist who's challenging me. Can you give me a tough time? Yeah, this can't be just all.

Okay, softball. Let's play a little hardball. So I guess my issue, we're looking for a planet. Again, this is in the themes of the movie. We're looking for a planet like Earth, similar enough to Earth, that we can send people there to continue our civilization and our species. Is that a fair characterization of a plotline? The plotline, okay.

And it turns out there's like a wormhole that can make that happen a little faster, because otherwise you don't live long enough to travel the distances with the rockets available to hit those destinations. Okay. I'm just thinking this blight on the crops that was starving everyone on earth, requiring that we jump ship, literally jump ship to go find another ship, another spaceship planet. It seems to me

that whatever effort it takes to find another Earth, travel through a wormhole, ship a billion, the Terraform it, ship a billion people there, whatever that effort is, seems to me,

to be a bigger effort than just telling the biologist come up with a serum that could fix the crops. Even today, we have full knowledge of crop genomes. Just fix it. Whatever is, just go in there, just nip tuck the DNA, fix it. Isn't that cheaper, easier, faster than worm holding your way off this planet? That's where I'm coming from.

You think that all problems can be solved by humans with human technology on a time scale. You have such faith in humans. Come on. So I'm the optimist here. Okay, so let me describe. This characterizes how this movie was done. So when it was John and Owen, Chris's brother, who came up with the idea that he wanted a blight,

or something like that. And so we said, okay, we will bring together the best biologists we can, who are experts on these kinds of things, put together mostly Caltech biologists. And we had a dinner.

And we brought out a very expensive wine for them to drink. And we set up a recording in Vino Veritas. And truth there is wine. And wine there is truth. Yes. And so we had a conversation that lasted about three or four hours at the Caltech Faculty Club, the Athenaeum.

about what would be the best backstory here. There are two types of blights. There are generalized blights that attacked lots of crops. And there are lots of different species of crops.

But they are generally fairly benign blights, and then there are blights that are very specific to a particular crop, and they can be very lethal blights that may totally wipe out that species on Earth even. But basically, for Earth to serve Earth and life on Earth to survive, you better not have a vicious generalized blight.

But according to the biologists that I discussed this with, they didn't know of anything that would prevent the development of a very vicious generalized light. So that's what occurs in this movie. And it's something that biologists have never seen, but they cannot

Rule it out. Okay, so let me repeat what I think you said. They have vicious lethal blights that attack a species, less lethal generalized blights that cross species boundaries, and they can't rule out a lethal blight.

that would cross species. That's right. And so that's what's happening in the film. And that's what they just, the biologists in the back. So they're in the back. I'll give you that. Okay. Okay. So anyway, this film is full of backstories because of the way we did it. As I say, again, it's unlike almost any other film and that these issues were like that. We're vetted.

We're vetted by the world's best experts in the process of the writing of the screenplay. Okay. I'm Nicholas Costella and I'm a proud supporter of StarTalk on Patreon. This is StarTalk with Neil deGrasse Tyson.

But I got another one. Okay, you're one for one. All right. When they're on the black hole planet. Okay. And then they see this wave coming. Okay. It's Miller's planet. Miller's planet. The water planet. The planet orbiting Gargantuan. Gargantua. Okay. The strength of tidal forces are highly sensitive to the distance you are to that which is causing the tides. Highly sensitive. Okay.

But every illustration I've drawn or taught about tides, they're not so peaky. They're much broader in their representation on a planet. And so there they are, wading in water,

but then they see this single wave come. And if it is a single wave, as we've seen with tsunamis, it actually takes water away from what's ahead of it. Because it can't just be water out of nowhere, it's drawing water from its vicinity. So my two issues was, if it's tidal, would it be that peaky? And if it's any kind of wave, how could it still leave the water laying around its vicinity and then just be that big as it came by?

So there is a type of wave called a solitary wave on water that was... You could tell me you brought wave people together and had that lunch. No way. This particular kind of wave was discovered in the 1700s by a forgotten who a physicist in England who saw a boat that was being pulled by horses.

and it was just starting up, and it created this wave that traveled down a channel, a canal, and it was peaked to like the waving interstellar. Though the waving interstellar, I have to admit, it was exaggerated. There was some exaggeration in the peak, but it traveled down the channel. It never broke. Most waves at the ocean, they break.

Okay, just so we can get the picture, because we're talking about centuries ago. When you say a channel, that would be a channel working out. And then there's a toe path on the side. And then people, and more likely beast of burden, would drag things through the canal. Because they themselves don't typically have courage. Drag a barge down the car. A barge, exactly.

And so this barge was dragged down the canal and it was just starting up and it created this wave that on the startup and it just headed out and just took off and went down the channel and this guy got on his horse and he followed down the channel.

And it went down the channel for, I don't know, a mile or two without changing its shape, without breaking. And so the theory of these waves is that there are two different effects that cause a wave to steepen

or disperse, and the two can balance each other out in a stable sort of a way. And give it longer life. And give it a long life. And so, aside from the issue of friction, if there were no friction, it would just live forever and keep propagating in a very stable way.

It's, there's a mathematics behind it, something called the Cordaveg de Vries equation that this is a solution of. But anyway, these waves then… So that equation, I presume, has both kinds of waves in equilibrium somehow represented. Yeah, the two aesthetics wave. The dispersion and the steepening. The steeping is due to non-linearities. The dispersion is due to the fact that

that they hire parts of the water travel faster than the lower parts of the water. If you're at the ocean, you see a little tiny wave, it travels quite slowly. You see a big wave, it travels quite fast. And that's why the crest of the wave will actually break before the rest of the wave gets there. Yeah, that's right. That's right. Unless that's being balanced out by dispersion, which is...

Anyway, I'm getting a slightly confused. But anyway, the two effects balance each other and to produce this very stable solitary wave. And so in the movie, but in for this stable solitary wave, the height of the wave.

is, and I've forgotten the number, but it's something like six times higher than the depth of the water. So there's a problem now in the movie because they're walking around in shallow water, and this wave is high, and so it's got to be deep water. But they're on an island.

This is a backstory. Again, there's always a backstory. So they're on a subterranean, a sub-surface island. You got to read it in my book.

They're on an island, and this wave diffracts around the island, hardly noticed the island at all. So again, it's all explainable, except there is a bit of exaggeration. The CGI wave was made somewhat more peak, somewhat higher than it would be.

But what you're saying is this wave might have been caused by some effect other than the tidal forces of the black hole. Yeah, well, this wave is caused, in fact, by the fact that this time is much slowed on this planet. So the planet has been put into the orbit around gargantuan, not that long ago is seen on the planet.

though it's a long, long time ago is seen from far away. And it's like Mercury, like the moon keeps one face toward earth or Mercury keeps one face toward the sun due to tidal effects. This planet is distorted by tidal effects and it's swinging back and forth. It has not yet settled down to one face toward the planet. And that swinging back and forth is generating this wave. It's all in the book. He weaseled out of another one. Okay.

There's an enormous amount of science in that book. I must have missed that when I went through the book. And one last point. You didn't study it carefully enough. One last point, we took our show to Oxford recently and interviewed an Oxford, I think was a postdoc.

And I was named Andrew Mumery postdoc. And he showed us a recent paper he published. I don't know if you've seen it recently, like within the past 18 months. And he's a theoretical physicist and he

And alerted me, it's something I'd never knew. I love the field, but it's not my active professional field, that in the vicinity of a black hole, there is an innermost orbit, because of course you can orbit any source of gravity, even if it's a black hole. But for black holes in particular, there's an orbit within which the orbit is no longer stable and it will spiral into the black hole itself. And according to his calculation,

to get the time dilation necessary in this scene with the black hole planet, which was huge. Remember, they were on the planet for like 15 minutes or whatever. Well, one hour on the planet is seven years up in their spaceship, okay? And the guy where they left there, he's like gray and unshaven and everything. And we're like, oh my gosh, there's some serious Einsteinian physics going on here. His calculations showed that for that

difference, for that extreme difference in time dilation, requires that planet orbit so close to the black hole that would be on an unstable zone. And so I just thought I'd tell you that. My calculation says otherwise.

And where's his Nobel Prize? The other guy. The formula is in the book. So we don't have to go to your graduate textbook for that. No, not for the answer. If you want to derive the formula, that's a lot of work. So let me tell you the story behind this.

Christopher Nolan says to me one day, he says, I want the hero and Cooper, the hero in this movie to go down onto this planet. Cooper played by Matthew McConaughey. Professor Bran's daughter is played by Jessica Chestey. Christopher Nolan says to me, he says, I want in this movie.

that one hour on Miller's planet is seven years up at very high orbit or back on Earth. You prescribe that. And I said to him, that's impossible because the planet will fall into the black hole. He said, go do a real calculation. I've already learned that you're off the cuff. Reactions can be wrong. And I should not trust you unless you do a real calculation. There's a good Hollywood producer. Go back and give me the answer I'm looking for.

Well, and so I went back home and I did a real calculation and I was amazed that the last stable circular orbit, which is what we're talking about, is if the planet spins fast enough, the last circular stable orbit can have as high

a high a redshift as high a time difference as you might wish. But that requires it requires that this black hole spin extremely close to the maximum possible spin.

And so in the book, I give the formula for what is the spin of the black hole that is required to produce a given amount of slowing of time. And so it's an approximate formula, but it's a formula that can be derived.

They're a bit of algebra. The one one would just learn about would probably be the lowest stable orbit around a non-rotating black hole. That's a clean problem. That's what I was thinking when Chris got along with this.

And I knew that if I made the black hole spin, that it would get closer, but I couldn't imagine. I could not imagine that nature would provide it orbit for a black hole that spins fast enough that they could provide as much of a slowing of time. But it does, it does, at least unless I made a mathematical error. But I don't think that's likely because I used Mathematica.

Okay, you had tools to help you do this because it was it's not just an analytic solution. Well, it is an analytic solution, but it's very complicated. Very complicated. Yeah. Well, it's a power series solution. In the end, I think the our hero character is inside the black hole. We come to understand this and he has access to a timeline.

that wouldn't otherwise be available to him. And he sees his daughter's bookshelf. He's no longer inside the black hole. Where is he when he's doing so? This is the key thing that's not explicit that you only understand if you read my book.

You didn't read it well enough. I read a lot of it. I read some of the biology. It was a long time ago too. When he gets inside the black hole, he is scooped up by a

a spacecraft that was built by this advanced civilization that provided the wormhole to him, to humanity. It's called the Tesseract. Tesseract is a four-dimensional cube, four spatial dimensions. That's why in there you saw

I guess the past and future all kind of related to the very higher dimensional. Yeah, that's right. So this test rack, he so let me back up. I'll tell you a story. So early on in when we were working on the film, Christopher Nolan said to me, he wanted to take his hero back to earth, Cooper back to earth.

by a different route than the wormhole, 10 billion light years away from the earth. How's he going to do it if it doesn't go through a wormhole? He said, well, I want to take him back faster in the speed of light. And of course, I say to Chris, you can't do that violates the laws of physics. He says, go to a real calculation. I said, I don't have to do a real calculation. And so we discussed this for a week. And then he threw in the towel. He said, OK, I believe you.

And so what do we do? And so I said, well, you put him, he goes inside the black hole. He gets deposited on the three-dimensional surface of a four-dimensional sphere. And this four-dimensional sphere is a spacecraft that can go into the bulk, into the higher dimension.

and it goes out of the black hole, not through the horizon. It can't do that. It goes up through the fourth dimension, up through the fourth space dimension, or what's called the fifth dimension in the movie, is time as the fourth dimension, and goes back to earth. And the distance back to the earth is less than the distance between the earth and the sun.

even though it's 10 billion light years inside of our universe, up in the bulk, it's a very short distance. And so we can get back very quickly. This is the higher dimensional spacetime in which we are now having this. So he gets back very quickly, riding on the surface, this four-dimensional sphere. He said, I like it all entirely, except I'm going to use a four-dimensional cube instead of a four-dimensional sphere. That's a tesseract. Yes.

And so that's what happens. And when you see Cooper out there sort of flailing around at the beginning of the Tesseract scene, he's being carried by the Tesseract back to earth. But you don't know that's what happened until you read my book.

By agreement, Rain Chris and me. That's the only way. So anyway, he's carried back to earth and then everything is happening when the Tesseract is docked in the higher dimension beside his giving access to his life in that past time. That's right. So it's docked in his home, in his daughter's bedroom. Okay. So now he's pushing books off the shelves

that land on the floor and through some clever cryptographic judgment, he's spelling out words with the first letter of the title of each book. Okay, here's my issue. I had no problems with Tesseract, black hole, worth the mention, five dimensions. How does he know the title of each book from the other side of the book?

So I don't remember that's how he's actually. He's pushing books. No, I know he's pushing. I know he's pushing out from this side. Yeah. Yeah. And all he sees is the other side of the library. I guess I had forgotten that he was spelling things out based on the first word. Oh, you forgot. I forgot or I didn't know. Are you are you're wrong?

So that's one of my. That one, I don't know. Oh, okay. Okay. I don't know. Okay. So you're, you're three for four. He probably has a photographic memory of the other side of the book. What's this I hear that?

you can use a wormhole to travel backwards in time. Does the math check out? Does the Einsteinian physics check out? And does that mean I will just show up a younger version of myself and shake my own hand? Is that what you mean by that? Or do I no longer exist in the time that I left for my younger version of myself to see that? And wasn't there, I didn't hawking put forth a time travel

prevention conjecture or something? What's going on there? So this is all an outgrowth of my phone conversation with Carl Sagan when he was working on the novel for contact.

where he triggered me to start thinking about wormholes, and then having started to think about wormholes, it became pretty obvious to me rather quickly that if I give my wife,

barely one mouth of a wormhole. And she carries it at high speed in a rocket ship out into space and then back. And I keep the other word mouth at home. And if she she sees me age by 50 years back on Earth, well, she ages only one year going out and coming back.

But if we look through the wormhole at each other, we see each other aging at the same rate. Just imagine we hold hands and we look at each other's wristwatches. They're picking away at the same rate. So through the wormhole, we page to the same rate, we're the same age. But looking through outward, through outside the wormhole. Through a normal universe.

She's aged one year and I've aged 50 years something weird to happen the wormholes become a time machine. I just go over and go into her mouth wormhole mouth and come out i'll meet my younger self.

Okay, now Hawking said this is, no, we're not going to allow this. There's some conjecture yet to be discovered that'll tell you you can't do that. Well, so we get there. You're going too fast. I'm going too fast. Sorry.

I taught their friends at the University of Chicago. Physics, it's crucial to talk to friends. They tell you where you're all at. They tell you when you made a mistake. They straighten you out. They pointed out to me that it might be that when the time machine is turned on, it will self-destruct, basically. They said, I don't understand. They said, go do a calculation, so I went and did a calculation.

And the issue is, and they had guessed, and basically it's oversimplified, but they, Bob Garroch and Robert Wald at Chicago. Anyway, it turns out that at the moment that you can first time travel, the first thing that goes through, it can be vacuum fluctuations of light, say, that enter her mouth of the wormhole, come out of my mouth and go back

and arrive back at her mouth at the very moment they started out. Now you have twice as much at the same place in space and time.

So this is a runaway. So it's a runaway. And so they you now have twice as much. And then it goes around again. Now you have four times as much goes around again. So this runaway builds up. Just like the feedback between a microphone and a speaker. Precisely. And it just runs away. It just runs away. It runs away. And this runaway shows up in the quantum mechanical calculation that

that I did bumming me out together with the San Juan Kim, a Korean postdoc of mine. OK, I'm going to be a movie director and say go.

Kip, go home and figure out how to do this. Give me another, pull another rabbit out of the hat here. Well, anyway, we discovered this, Stephen, I think, in one of his Stephen Hawking, and the student of his, I think, had more or less the same discovery at the same time, except Stephen probably just did it all in his head, because that's the way Stephen is.

Anyway, so then Stevens and I started corresponding about it by email and talking on the phone about it and so forth. It appeared to me, looking at the details of the calculation, that in fact the explosion, if I designed the time machine just right, the details of the explosion would not be strong enough to destroy the wormhole. And Steven then showed me that I was wrong.

And we argued back and forth for a while. Finally, we came to agree that the explosion becomes strong enough that quantum gravity enters in and then holds the answer tightly in its grip. And so we won't know whether the time machine delved the struts until we understand the laws of quantum gravity. But then we come to the Hawking's cosmic censorship conjecture.

That's what it's called. Yeah, he's a conjecture that, in fact, in the end, the laws of quantum gravity won't save the day. The wormhole will be destroyed. And any time machine, any advanced civilization makes will be destroyed when they try to turn it on by these vacuum fluctuations. And thereby, as Hawking says, keeping the universe safe for historians of all species.

It reminds me of the ultraviolet catastrophe, where you run the calculation, this is gonna blow up, how does this even work? And then, out comes the discovery of the quantum, which saves the day, right? And this is, it could be a calculation waiting for another branch of physics to open, or another progress in the known branches of physics to resolve.

We in LIGO and I grab a new project. I'll just make the remark that we have we the LIGO team has has perfected a technique called quantum precision measurement, which is based on manipulating vacuum fluctuations in order to circumvent the uncertainty principle.

And so this business of manipulating vacuum fluctuations is something we do in modern physics. If memory serves, Carl Sagan came up to you and said, for contact, I want to go far distances quickly. How am I going to do it? Can you cook up a wormhole for me? Carl phoned me.

Well, back in the 80s. When he's writing the novel, when he's writing the novel, we dated the movie. That's right. And he said that he wanted that he has written, he'd already written the book, the novel. It was already in page proofs.

And he said, I've got this novel. It's in page proof that publish is not going to be happy if I change it by really need some help to see what the truth is. And then we'll figure out how to deal with this. And he said that I have my heroine.

traveling through a black hole to get to the Star Vega. And I said, that's rather dangerous. There's a singularity in there and you can't get through to the Star Vega. So what you actually need is a wormhole.

But there is an issue that wormholes implode they collapse so quick that nothing can get through But I'll see if I can figure out how to hold a wormhole open just for you Carl

And so I was going with... It's like rent a physician. It's like, whatever your needs are. So I was getting in a car that morning to ride with my former wife, our daughter's graduation up at Santa Cruz. And so Linda was said, I'll drive and you calculate.

and I calculated, I fiddled around, and then it became fairly obvious. Turns out some other physicists have figured this out sooner, but that's the usual thing with me. I figured out, and then I go see, did people know this before or not? So anyway, I figured out that if you had what I like to call exotic matter,

that repels gravitationally, and you put it inside the throat of a wormhole, that can hold the wormhole. It'll be like pushing it outward. That's right. It basically repels the walls of wormhole to hold them open.

And it turns out that that will do it. But you have to have enough exotic matter to hold the wormhole open. And I deduced a formula for how much you had to have. And it basically says the following. If you move through the wormhole... But the record show he's about to describe how to make a wormhole.

No, only how to hold it all. Only how much you thought it mattered. You have to hold it open. So you travel through the wormhole as close to the speed of light as you possibly can, just close to the speed of light. And you add up all the energy density all the way through the wormhole of stuff that's in the wormhole.

The net has to be negative and then you know the whole hope and so it basically means you've got more negative energy than there than positive and cook we have nothing. Known as exotic matter always we do. What yeah and so that is in your basement is. What do you know what what what do you know yes we do what what okay what what is our exotic matter that would fulfill this purpose.

Shall we turn off the camera now? Is the government going to show up on your driveway? I learned about this from Yaakov Borisovich Zaldovich in Moscow. Zaldovich was one of the inventors of the Russian hydrogen bomb. I learned this from him. He was really brilliant. I learned about vacuum fluctuations.

and how important they can be, and how powerful it can be if you can manipulate them. And so if you take a box and you remove everything that can possibly be removed from the box, you're left in the end with tiny fluctuations of everything that cost possibly could have been in the box.

So electric fields, you have fluctuating electric fields, fluctuating magnetic fields, fluctuating protons, electrons, fluctuating Nealtis and the Krastisons. So this creates a form of pressure inside the box? Well, so there's vanishing pressure and not vanishing energy due to renormalization.

That's a nasty word in physics. You can measure energy by whether it produces gravity or not.

And although these fluctuations that are there, you can think of them as particles, say particles of light, flashing in and out of existence randomly. So why isn't this not the virtual particles that people speak of? So it's virtual particles. It is that. OK, we've spoken about those on our show before. OK, so you have virtual particles in fact. So you have virtual particles in the vacuum popping in and out of existence. And you can't stop it. You can't prevent it.

However, you can take fluctuations from one region and borrow them and put them in another adjacent region for a little while.

or if you put an electrically conducting sheet, say a sheet of superconducting metal here, then that will suppress the fluctuating electric fields parallel to the metal because they would create an infinite current flowing in that metal. And that would wipe out the electric field parallel to the metal.

And so you have an element of the chasmere effect? Yes, that's the chasmere effect. It is. Yeah, we have two parallel plates evacuated between them. That's right. And there's a point where they actually feel a whole other force contracting them. And so what that force really is is in the region between them, the vacuum fluctuations are suppressed.

And so you have negative energy in between. That energy, negative energy is sucking them together. And you have, you have, they can do work on you if you, you're holding onto these plates. And they attract each other. You put energy in as they go. As they go together, they do work on you. The electric, electromagnetic field between two plates in the Casmer effect is exotic.

Okay. So you have this in your basement is what you're telling me. Yeah, I don't have it in my basement, but physicists do this. Let me just say as a side remark, having learned a lot about vacuum fluctuations, we in LIGO and I grabbed a wave project. I'll just make the remark that the LIGO team has perfected

a technique called quantum precision measurement, which is based on manipulating vacuum fluctuations in order to circumvent the uncertainty principle. And so this business of manipulating vacuum fluctuations is something we do in modern physics. And it is something then that you can imagine, you can ask, can a very advanced civilization

manipulate vacuum fluctuations adequately in order to make enough exotic matter inside a wormhole to hold the wormhole open. And so I posed this as a question to my physicist colleagues, stimulated by Carl Sagan and him wanting to send his heroine through a black hole. I said, no, he was a wormhole.

And so we've got to hold it open. And so, physicists, colleagues, please help Carl and figure out can an advanced civilization do this? And the answer is we still don't know 40 years later now, we still don't know. Right. Well, we're doing magic compared to what anyone thought was possible 50 years ago. Certainly the dawn of quantum physics. We're on the centennial of the decade of quantum discovery back in the 1920s.

Well, I had was very close friends with Carl Sagan, and I've developed close friendship with Christopher Nolan. Chris has a very different background than me. He knows a lot of science, but he's learned all by browsing the web. And he knows it well enough to ask me hard questions. That's just like you do. But he asked them first, so I have the answers now.

So he and has inspired me to ask questions that then I sort of translate to and give to colleagues because my colleagues are smarter than I am. My role is to pass on interests and questions for this, for interesting question for my colleagues to work on. So,

Dude, you can't leave well enough alone. Einstein says, maybe there are gravitational waves emanating from major gravitational disturbances in the universe, and you got to go up and find them. But you're not the first to have attempted this, right? At the University of Maryland, there was Weber, I think. What's his first name? Joe. Joe Weber, of course, who had a cylinder, if I remember correctly, where he was trying to measure

whether if a gravitational wave washed over it, he could detect a distortion in the shape of the cylinder, I think was the goal. The gravitational wave would drive vibrations of the cylinder and in vibrations. And so he instrumented it to search for changes in the

amplitude and phase of vibrations of the cylinders, cylinders at a finite temperature. So it's always vibrating a little bit because it's a finite temperature. And so he instrumented it with what's called the atoelectric transducers, transducers that he glued around the middle of the cylinder.

that when they were squeezed, they would generate an electrical voltage that he could measure. They're amazing things. This Pietso electric transducer is just absolutely amazing. You squeeze them a tiny, tiny bit and you get a big voltage out. Joe Weber was tremendously creative. I think he was working on that while I was at the University of Maryland. I was there in the 80s. I think he was still working on it. Yeah, that's right. So he began working on it in the

late 60s, early 70s, and announced that he was seeing possible evidence for gravitational waves in... There's a lot of skepticism at the time. I'm sorry. He started working out in the late 50s, early 60s, announced in 69 that he was seeing some possible evidence of gravitational waves.

And a number of other physicists around the world built similar detectors and the bottom line in the end after a period of shaking out was that others were not seeing gravitational waves. And that's the only way science works.

But if one person's result is not a result until somebody else, a competitor, somebody else who uses different wall current, somebody from another country, you need multiple verification. But on the other hand, Weber, Joe, he started the field. He triggered this work.

The approach that he invented for searching for gravitational waves was the dominant approach from then until the 2000s. And a number of other research groups built similar detectors and improved them better and better and better.

over that period of time on that model in the model. So, I mean, I have enormous respect for what he did. Now you decided to you and others.

decided to look differently for them. Yeah, well, so Ray Weiss, Reiner Weiss, Ray, his friends call him, at MIT, was the primary inventor of an alternative technique that was the technique that ultimately succeeded. He invented it. He wrote

He wrote a technical paper about the technique that identified all of the kinds of noise that you would have to deal with and explained how you might deal with them and did analysis of how good this detector could be.

And he put it all in this paper. So it was a recipe for how to go forward. And he wrote this in 1972. And Ray being Ray didn't publish this because I think he figured you don't publish until you have built one and seen a gravitational wave. So but however Ray sent copies of this around all his colleagues,

And he put it into quarterly reports of the MIT laboratory in which he worked. And so it is probably the most influential non-published paper, certainly that I know of in physics. I mean, it was a tour de force and it triggered the huge effort that actually succeeded.

I was fortunate enough to visit the, because there are two LIGO experiments. One in Louisiana and the other one is in Hanford, Washington. Why do you have two? Because you can't just have one result. You're looking for an effect that is so small that you wouldn't believe it unless you see it on two independent instruments. There you go. So you've got these pathways.

Are they kilometer long? Four kilometers long. Four kilometers long. Evacuated, you send a beam of light that is split from a beam, a laser, that's split. It goes two, these are at 90 degree angles, and they go to the end, they get reflected back, and you rejoin them, and you want to see if their waves line up. And if they line up, then each direction is identical,

You can go home. If they're slightly different than one of these legs experience a different encounter with the fabric of the space-time continuum than the other did.

So that's, you know, that's what it's actually what you want to do is you make them slightly different than the first place. But then, so that means you send, you send your laser light in from this direction. There's a beam splitter where the light gets split in two to go down the two arms. So laser light goes in like that. There's this beam splitter. So the light gets split in two into one arm in that direction, the other arm in this direction.

And then it comes back and recombines in the beam splitter. The laser light was coming in from this direction. But when it recombines, a little bit of light goes out in a perpendicular direction. So you have a laser here and you have an output over there. And the output direction is the direction it has a signal. And if the

if the length of one arm is shortened and the length of the other arm is in length. And that would only happen because a gravitational wave warmed over that arm. Then you get a change in how much light is coming out to the output. All right, so you're trying to find a chain of length difference. And if I remember the materials from the press releases that is equivalent to one tenth

The diameter of a proton? No, it's equivalent to it's 10 million times smaller than an atom and a hundred times smaller than a proton. One hundredth.

the diameter of a proton. Meanwhile, all the world is vibrating because everything is at a temperature and cool it as much as you want. There's still vibrations. And somebody's walking down the street. I remember being on campus there. Can I call it a campus? That's what it was. And you can detect cars on the road a mile away.

You have to insulate this. That's half the science done for the experiment. You should get a Nobel Prize for that.

Well, that's what the Nobel Prize was doing for that. To have successfully isolated the effect you're trying to measure. So the way I like to describe it is you're trying to, you're bouncing light off these mirrors and you're looking for a motion of the mirrors that is 10 million times smaller than the atoms of which the mirrors are made.

And the atoms in the mirrors themselves are vibrating because they're at finite temperature. By an amount is about the same as their size. So a million times smaller than the atoms and a 10 million times smaller than the vibrations the atoms are undergoing. So once again in physics, there's a phenomenon we're trying to measure.

but it's kind of buried and you need a way to get to it. And it seems like half, if not more than half of the effort, is how brilliant is your engineer that you've brought onto the task to accomplish this? How good are your tools? It's not just the idea. It's now you gotta make the damn measurement. And it's not obvious. You need very talented people assembled for this.

Absolutely. And so that was the issue is how good a team can you put together. So when I learned of Ray Weiss's idea and I saw and I knew roughly how strong the strongest gravitational waves would be, I knew already then that it would be necessary to. This would be the collision of two black holes.

of two black. And you can't just summon that up. There has to be real things in the universe that might produce that. That's right. So based on what we knew about the universe at the time, I was estimating a wave strength. It was roughly correct. And it was at that level that you would have to monitor the motion of these mirrors at 10 million times smaller than the atoms in the mirrors. And I thought to myself, that's crazy.

And so in this book, which was published in 1973, we went to press just after Ray Weiss wrote his seminal paper. I had not yet really studied that paper fully.

But I just knew that this was crazy. And so it describes in a few words, raise idea in here. And then it says, I think there's an exercise where it says, show why this is not very promising.

Just a mild gentleman. Because it is a textbook, right? You get to know where that is. So it's a student's challenge to show. Well, it could not be a very good idea in 1973, but fast forward a half a century. Right. So it is 1853. Flying is not a good idea, right? An essay on why flying isn't a good idea. But that was the central issue. If we worked for a few decades,

Did we have a shot of success? In 1973, I thought, no, no way. But by 1975, I had turned around. I'd had long conversations with Ray. It had long conversations with Vladimir Brzezinski, a colleague in Moscow. I'd done lots of calculations of my own.

And I came to the conclusion that you had a real shot at success if you put together a superbly strong team and you worked at it for a few decades. And you need money and you were well supported, I think, by the National Science Foundation? Well, not yet. So at that point, NSF had given Ray $60,000 to get started.

And that's how much he had in the 1970s from the National Science Foundation. He also had some money from the Air Force Office of Scientific Research. I'm not sure how much he had, or he had had that. Until in the Vietnam era, they stopped supporting science due to something called the Mansfield Amendment, American politics.

And that's when NSF picked him up and gave him 60,000. That was a drop in the bucket compared to what was needed. And NSF wasn't about ready to put big money in. It's required some members of your team to appear in front of Congress to defend this. That's correct. And that was much later. The issue was getting started. And so how did we get started? Caltech is a very different kind of an institution than any other I've ever dealt with.

Caltech, I was able to say, to propose to my colleagues that we get into this field, that we build an experimental program in parallel with Ray Weiss's program at MIT. So the chair of the Division of Physics, Mathematics and Astronomy at Caltech set up a committee to look at it.

Committee looked at it for about six months, detailed study, came back and enthusiastic said let's go ahead. So Caltech put private money about two million dollars of its own private money to get started. And that inflates about 12 million dollars today.

of private money when nobody else is putting anything in. You're right. That's a very different point, a very different culture in Caltech. And once that had happened, and we had brought Ron Drever from Scotland to start the experimental effort, then NSF. And NSF stood up and took notice.

They did their own study of this and came up with the same conclusion. They started funding us, us and Ray Weiss, and it became a Caltech MIT collaboration. Let's fast forward to 2016, where you make the first detection.

No, he announced in 16. You announced it in 16. By the way, I would later learn that when I visited the facility in Louisiana, you already had made the detection. And you'd be happy to know that everyone was completely zip-mouthed about it until it was officially. Because I have this huge, like, internet following, right? And people were totally zip-mouthed.

I swear I didn't know about it until the press release came. We were all sworn to see who she was. The confirmation of a first detection came from the second facility built in Hanford. At that point, you have a timed away.

because gravitational waves move at the speed of light, correct? So, and Earth is a finite size. And so all that worked out. Yeah. And so it was just seven milliseconds, seven or one half of a second time difference, because the waves came up from the south. They entered the Earth around the tip of the Antarctic Peninsula, traveled through the Earth,

I came up through the earth in Louisiana first, and in Washington State, seven milliseconds later. And then the waves were unaffected by all the matter of the earth.

And they couldn't see the difference between the earth and no earth. And they couldn't see the difference between detector and no detector. They were very hard to do. They're doing their thing. So what impresses me greatly is here we have a prediction made by Albert Einstein when in 1916 or 15, whatever, Albert Einstein in a little known back, I mean, physicists know this, but I don't think the public knows Einstein laid out the equations

for the stimulated emission of radiation, which is the physical foundation of a laser. He wrote that down first. And a laser would take a few decades to actually be built into the 1950s. And I'm just saying, here's Einstein predicting gravitational waves, laying the foundation for a laser. And a hundred years later, his gravitational waves are found with lasers.

So these are crumbs spilling off his plate. Einstein was kind of smart. And lo and behold, nobody's surprised. The Nobel Prize goes to this project. And you along with Ray Weiss and Barry Barish shared the Nobel Prize. What year was that? 2017?

So they apologized to us. They didn't give us in 16 because we didn't announce it until past their deadline for a destination. Anyway, they never know. They said it obviously. It was obvious. The prize was going for this. It was just obvious.

You can't be a general relativity Einstein guy without being a black hole guy. So forgive me for asking you to retell a story you've probably told a thousand times, but there's some famous bet you made

was it with Preskull with some other physicists? Preskull and Hawking. And Stephen Hawking. By the way, I was at the University of Texas when Preskull was there. I think he was like a postdoc or something. He was just starting out. That's how old I am. I'm an old guy. I'm an old guy. You're a young kid. I'm an old man. So you made a bet. And let me see if I can set the table here. A black hole

Once we all agree that they exist, we can ask other questions. When you have something outside the black hole and it falls in, what happens to that information that was contained in that object? Is it gone forever? And is that okay? Because information theory was a whole branch of science, shall I call it science, that was rising up.

at around the same time and entropy became a buzzword among many. So what was the bet and how was it ultimately resolved? So the bet was between Stephen Hawking and me on one side, John Preskel on the other side. It was over whether or not information does get lost in black holes.

Why is that so bad? It's bad because the fundamental laws of quantum mechanics as they are normally formulated. Physicists are widely agreed

that quantum physics is fundamental and that quantum physics underlies all of physics. It's the most successful theory ever put forth of the universe. And classical physics, where there are not these quantum fluctuations, there are not these probabilities

That arises from quantum physics as an approximation under ordinary everyday circumstances. There are many people who caricature science physics in particular by saying, well, we used to think classical physics was it, but now we discard it in favor of quantum physics. But that's not true. No, quantum physics absorbed as well as relativity, general relativity absorbing

Newtonian gravity. It's not discarded. It's a bigger understanding, a deeper understanding. Just want to emphasize that. Many people get that confused. So quantum physics is normally formulated, almost universally viewed, has built right into it for the very beginning the fact that information cannot be lost.

Now, these words information cannot be lost or a translation into everyday language of something else, which is not everyday language, which says that the evolution of everything in the universe is unitary.

And so those are buzz words that are not part of the normal lexicon, but I want to say just to say that we indicate that there's some very, very extremely precise version of this of which information is being lost is a colloquial way of saying it.

but it would represent a violation of some fundamental tenets of quantum theory. That's right. Stephen Hawking back when he was visiting Caltech. Who, by the way, we've interviewed for StarTalk in our archives. Check it out.

In 1974-75, he spent a year in my research group at Caltech. We were very close friends. And during that period, he having discovered something called Hawking radiation, which is a very slow evaporation of a black quality, and its radiation slowly evaporates.

He then, while he was here, he began to look much more deeply at quantum theory in black holes. And he came up with a prediction that information really is lost. And when black holes evaporate, you could form a black hole. If you waited long enough, much longer than the age of the universe for normal black holes, the black hole would evaporate.

And all the information that went into the black hole would be gone. The black hole would be gone. You just simply lost the information that no longer is there. And that was complete violation of the normal tenets of quantum mechanics. And yet he was claiming that that was true. He wrote a paper on this with all the technical details. You couldn't get it published.

It was so obvious. It had to be wrong, but nobody could see anything wrong in his calculation. He had to fight for more than a year to get a published. If you look at this paper, you see the submission date. As well, research papers give you.

They give you a submission date, and then you usually have a revised date, and then it's published. There's no revised date. There's a submission date, and the publication date is something like nearly a year and a half later. He fought for a whole year, a more than a year to get this thing published. And physicists struggled with this ever since.

So those of us whose roots are in relativity tended to believe hawking. And those of us whose roots were in who grew up with quantum mechanics instead of relativity first. Those of us who were in the amort of relativity tended to believe hawking. And so hawking and I made this bet with Preskill whose roots were in.

in quantum physics. He's the junior of you both. He's the junior of Whipper Snapper coming up. He is now the Richard P. Fimer professor of theoretical physics at Caltech. I'm the Richard P. Fimer professor of theoretical physics at Meredith. Meredith, okay, I'm young Whipper Snapper. Oh man, don't take your job in a minute. So I just earned the share over to John. I mean, John is brilliant. He's a hell of a lot smarter than I am. A hell of a lot smarter anyway.

So we made this bet. And this was in a period when Hawking was starting to visit Caltech for typically three to six weeks every year. Was he yet wheelchair bound? Oh, yeah. He was wheelchair bound going way back to about 1970. And this is 1990. Oh, what's this?

We made the bet around 1990. So the stage is set. The cage match is set. You and Stephen Hawking, titans in your field, in your subject, conclude, yeah, information is lost.

But especially if talking radiation, you can evaporate the black hole and everything is gone. There's no memory of what was there. Prescott is declaring that information is not lost and his roots are deep in quantum physics, which we know has never been shown to be wrong. They're both smarter than I am. They both know a lot more about quantum physics than I do because we'll return to this. But let me just explain that

Through my whole career, I've thought that the quantum gravity combining general relativity with quantum physics was the most important area of physics of all. But I also made a decision when I was very young, I will never work in quantum gravity, because the field is too crowded. There are too many smart people there.

I will pick, I'm smart enough to pick really important problems that I can solve that nobody else is working on. And they'll only figure out later that those problems are important. But I won't touch a problem wherever it is. But you've got a million people in the room. There's just too many smart people in the room.

So anyway, so they have now agreed that information is not lost. So hawking conceded and by association with you or have you still a holdout on this? I'm still a holdout.

Okay. And what led to this concession? If I understand correctly. So Stephen, together with a student, was working on an idea for how the information might be recovered. And he basically said that

In quantum physics, if you form a black hole and then it evaporates, there's also a tiny probability the black hole never formed in the first place and the information sneaks out through the root where it didn't form in the first place. I'm sorry, that sounds like a cop out.

Yeah, it does sound like it popped out, but it's very clever and it's in keeping with how physics works. But it's not obvious that it's right, but it's conceivable that this is what happened. What about the idea? So maybe I've misunderstood. So I've got to go back to see where I've said this even publicly. I thought as the black hole evaporates, because the gravitational energy and the vicinity of a black hole can spontaneously make a pair of particles.

And one particle escapes, the other one falls into the black hole. And this just keeps going until there's no black hole left. But the particle that escapes, if you inventory those particles, they're real particles. And don't you recover all the particles that went in in the first place?

Well, you recover all the energy. But they don't recover. But not the inventory of parts of the quarks. You don't get the same particle necessarily. How do you, okay, then I misunderstood that. I've been wrong. I think I've been wrong. I thought you get particle for particle. They come out, which blew my mind. I don't think that there's certainly there's no proof that that's the case. Well, of course, wait a week.

Certainly no proof, that's the case. I don't think it is the case. So you guys lost the bet. Well, no, I concede the bet. And what was at stake for this?

loser will give the winner in encyclopedia filled with information that somehow escaped the black hole. So information is the penalty gift. So Stephen Hawking conceded the bet at a big international conference on general relativity and gravitation in Dublin.

Ireland in early 2000s. With the gas in the audience. There were rumors that he was going to concede. And so there was a big ceremony that I played some role in the ceremony, but I didn't concede myself. And so Stephen gave Preskill, who's a big baseball fan and encyclopedia of American baseball.

Oh, any kind of encyclopedia. Well, that was his idea of that's clever. So anyway, so less expensive. Yeah, I didn't concede for a peculiar reason that there is an alternative formulation of quantum mechanics in which information could be lost. It's due to Feynman called a sum over history's formulation.

And as I say, I don't work in quantum theory in any deep sort of way. I do in terms of quantum technology, which we needed for LIGO, but that's a separate story. But two of the very deepest physicists in working in quantum theory of my lifetime were Murray Gellman,

and Jim Hardill. Jim Hardill is Santa Barbara, Gallimont at Caltech, and then he moved to the Santa Fe Institute in retirement. Gallimont is credited with proposing quarks as the fundamental particle of the giants of theoretical physics when I was a young physicist at Caltech where Gallimont and Feynman had two colleagues of mine that I'd enormously respect. So Gallimont and Hardill

took Feynman's path integral or some over history's approach to quantum mechanics and they developed it further and a form that they could apply it to cosmology to the universe. And then they hardly used that to study quantum cosmology, the quantum mechanical description of how the birth of the universe and how it has evolved.

That particular approach to quantum mechanics, Arnold took it and he showed how that approach can deal perfectly well with information loss. It deals with it, it arises because of what we call closed time-like curves. There's a certain probability for backward time travel.

in quantum physics. In this Feynman-Gelmon-Hardle approach, there's a certain probability for backward time travel. If you can have backward time travel at the quantum level, then you lose information.

And there's so the elegant mathematical formulation here. One of physics is so wheely this way. That's not the standard version of quantum mechanics, but that was the version that Feynman and that Hardlin-Gelmon needed in order to do the quantum mechanics of the entire universe and the birth of the universe.

So that we're getting into this issue of the birth of the universe and quantum gravity here. And I am rather enamored of this approach, although I don't do it. I just look on the storylines and admire these people who are smarter than I am and who have the courage to work in a crowded field. But I'm just so impressed with this. And with the fact that

Within that formulation, you can lose information. Is that the start of a formulation that will one day marry General Relativity and quantum physics? Well, it does do that. It's knocking on the door. It's knocking on the door. It's it's it's it's it's so remind me. Now, your professor born in this question. What is the problem?

with general relativity not melding together with quantum physics. What is the real hold up there? Well, the real hold up is that they are logically incompatible with each other, and so something has to give.

And that's because of the general relativity requires space to be continuous. You have a continuum space. And it's a very definite space. It's not a space where you have a certain probability that space is warped in this way and another probability is warped in that way. In fact, there are no probabilities at all. Yeah, there are classical probabilities, but not quantum, but not quantum probabilities. And so at the smallest scale, they're incompatible.

the smallest scale, they're incompatible in any place where gravity becomes extremely strong, they're incompatible. So the smallest scale, they're incompatible even here in this room, but also they're incompatible.

They're incompatible in the birth of the universe when gravity was extremely strong. They're incompatible in the core of a black hole or gravity is extremely strong. They're incompatible. If you try to make a time machine, Hawking and I independently with our students are identified a process whereby if a very advanced civilization tries to make a time machine, it will quite possibly explode at the moment you try to turn it on.

and that's also controlled by these laws of quantum gravity. So that's why we haven't seen any time travelers yet. Well, that's, that's, that may be the reason that they've been trying to turn on the machine. That's right. What you're saying is Einstein puts forth the general theory of relativity, which is so successful in so many realms, and it picked up where Newtonian gravity failed

yet we must confess or concede that there's a limit to how far general relativity goes, although we've yet to find a limit to quantum physics. So the betting pool will say general relativity is going to succumb to quantum physics in some way. Yeah, that's one way to say it. Certainly, there is the SN compatibility between the two. And string theorists are trying to be the, they're like,

performing the shotgun wedding between the two branches of physics somehow. And I do think, again, looking in from the outside, since I've chosen not to work in this field, that string theory is likely to be a successful route into the correct loss of quantum gravity. Yeah, but they've been in it for 50 years. Oh, yeah. That's not very long. Come on. I'm 84 years old. Come on. That's just a drop in the pocket. Come on.

But Einstein went from special relativity to general relativity in 10 years. Kepler went from weird nested solids to the Kepler's three laws of motion in 10 years, and that's lone scientists. We've been working to try to do controlled fusion for a lot more than 50 years.

LIGO took 50 years from the time I first started working on gravitational waves until we succeeded, it was 50 years. Some things take a long time. But LIGO is a machine. The merging of quantum physics and general relativity are ideas. Could it be? And I've said this, I don't want to say this to you because you're

You're Kip Thorne, but I've said this to Brian Green, okay? Because Brian Green is like my generation. I said to Brian Green, I said Brian, you've been working on strength theory for decades. Maybe all of you were just too stupid to figure it out and we're waiting for someone else to be born.

into this field to then solve it and win the ways none of the rest of you can. None of them are saying, I'm too stupid to figure this out. Let me choose another profession. No, they're saying the problem is too hard. And if you go 40 years of really smart people not figuring something out that tells me either they're barking up the wrong tree or none of them are smart enough.

Am I overreacting? I think you have to remember that we do build on each other. None of them by themselves are smart enough. But the community, again, it's like this Nobel Prize reading belongs to a thousand people. It doesn't belong to me.

With the Genesis and Joe Weber. With the Genesis and Joe Weber, we build, Newton spoke of standing on the shoulders of giants, and that really is true. If I can see farther than others, it's because I've stood on the shoulders of giants who have come before me.

And that's the nature of science. And the struggles that our colleagues have been having with string theory and M theory and quantum gravity, we've learned an enormous amount. It shows it's very promising, but it's going to continue on into the next generation before the older successes had very, very, very probably. Those are like final words right there.

I've heard rumor that whichever faculty of Caltech gets a Nobel Prize, they get a parking spot with their name on it. Is that true?

If I went at Caltech, Nobel Prize does not get you a parking spot and they want it, you have to pay for the parking spot just as much as you do without a Nobel Prize. That was such a fun rumor though, I heard that. That's true at USC, but it's not true at Caltech. Okay, because there's just too many of you all running around with Nobel Prizes. Then the parking spots are too valuable.

So true with USC. Okay. All right. So you're 84. You have 84 years of wisdom, coursing in your veins and arteries. Are there any projects you're working on in the next several years?

So I made a gradual transition conscious away from science, away from scientific research, beginning around 15 years ago. Oh, bye.

you know i would like to be like to believe i can live to a hundred and ten that's my intended goal and so for the next remaining decades. I wanted to do things that i really enjoy and i've enjoyed science i've been a conventional caltech professor for half a century, i normally enjoyed it enormously enjoyed working with students i trained to.

over 50 PhD students and who did far more important research than I did, and then they're done that. And I have worked in all these areas of science, and I've had enormous fun, but I've turned them over to the younger generation, and they're smarter than I am.

Okay, so what are you surfing now or skydiving? What are you taking up, other? So I decided that I would like to spend a few decades doing creative work at the interface between science and the arts. So interstellar is an example. That was going to be released in September, and then they delayed it to the holiday season in December. So the rerelease of winter release December is 2024. That's right. That's right.

That was enormously enjoyable. For men, I learned how great it can be to collaborate with somebody as brilliant and as completely different than I am, Christopher Nolan. My most recent collaboration has been

a book of poetry and paintings with Leah Halloran and about the warp side of the universe and my poetry, my attempts at poetry and her paintings, but just trying to see whether it's possible by tightly integrating paintings with verse to convey the essence of issues in science, the essential features without conveying the precise details.

No, that's not the right genre for precise details. But anyway, so I've been enjoying that. By the way, I've always felt that way about Van Gogh's Starry Night, where you look at that painting and you say, this is clearly not what he saw, but it's definitely what he felt. Yes. Yes. And you get to experience the universe through his own lens. Yes. And so I've always appreciated art when it plays that role.

I have a second movie that's been in the works for more than a decade. Well, it's just something that I started with Stephen Hawking and Linda Opes to as my partner on starting interstellar. It is wonderful to work with.

But that movie might never get made. I'm not going to tell you what it's about aside from the fact that it's sci-fi, and it's all in sci-fi, so you're trying to build in from the outset. So if that doesn't work out in the end, then I may try turning it into a novel. I've never tried to write a novel. I don't know whether I can, but it would be fun to try.

And actually the thing that I have put almost a large fraction of my effort in, the lion's share of my effort in since the beginning of the pandemic is a history of the LIGO project, the LIGO Gravitational Wave project. Because that is, I think, pretty clearly the technically most difficult thing that's ever been done by physicists. By anybody. By anybody. Yeah, probably by anybody. And 1-100th, the diameter of a proton, that's anybody.

And success required both developing amazing technology, new technologies, and required developing computer simulations of colliding black holes required.

developing quantum precision measurement technology that is now in LIGO and in playing a major role where you circumvent the, what's called the Heisenberg uncertainty principle. My mind is still partly blown by having, by you having said that. You're bypassing Heisenberg's uncertainty principle. Yeah, that's right. You, by manipulating vacuum fluctuations, just like

advanced civilizations, horrible as a routine thing. So we developed this new area of technology for LIGO. But it was also a very political thing. How do you get a billion dollars of taxpayer money for a field that didn't exist when you began?

And should they bet on you and not someone else? Of course, I think you even had naysayers if I remember correctly. Colleagues would say, this is a this is a prank. We had we had political battles in Washington. Yeah. Tell me who the naysayers were. I got people. They were they were some of the leading astronomers. I got people take. You want my people to.

They've come around in me. They've come around because this is so exciting now that LIGO's exceeded. The sociology of the transition from small science to big science is a very rocky process. That's the right word, sociology, because that's what it is. I don't like working in a big science project. It's not for me. Just like working in a crowded field is not for me. But this had to make the transfer

It wouldn't have happened otherwise. Conservation wouldn't have happened otherwise, and the genius of Barry Barish in making that happen was, and the genius of Robbie Voldt in getting us partway there, the very beginnings, our initial director, who was the one that sold it to Congress.

And it really got us going. It's a very complicated story. And I have a set of five collaborators that have been working on with this history. We just finished draft six and sent it out to like colleagues to comment on. And I have been getting back huge numbers with comments and it'll take me two more years, I think. So anyway,

This history, because of the nature of this project, it's a very interesting and complex history that is quite important for the history of science. Especially when you consider most people knew nothing of LIGO until they see the headline that it discovered gravitational waves, and why would they have any thought?

of what challenges receded that. They just read the result. Oh, scientists discover this. Well, how about the, like you said, the politics, the sociology, the genesis, the who's standing on whose shoulders, who the naysayers, all that has to be overcome. The international collaboration, key input from the Soviet Union in the depths of the Cold War.

And it's just a fascinating story and enormous fun. You know what Arthur C. Clark said, he said, in space where there is no air, a flag will not wave. So maybe the universe is not a place where we should be waving flags. Collaboration gets you there. I like that.

So, Kip, this has been at the light. Thanks for making time. A lot of fun. First, start talk. I look forward to the release of the re-release of Interstellar. We were recording this before that has come out. And you already know this, but let me reaffirm that that film just took people on a ride far beyond anything they had imagined.

It had kind of an impact on people in the way 2001, a space Odyssey did. It was mysterious, it was modern, it was the future, but it was still relevant, but it left you with more questions to ask than questions answered. And you want that, I think. Yeah, and that was really the genius of Christopher Nolan, taking some science that he and I had put together.

together, but combining with a human story that was powerful.

And with Marquis Director and Marquis Actors that made sure we'd get noticed. And music. Yes. I went to a concert by Hans Zimmer. Just I think the night before last. But I didn't know there that he basically said that certain pieces of the music and interstellar are as close to perfection as he has achieved.

I'm going to give it another listen, because there is no 2001 without its musical track with the Strauss Walses. This is very different. It's all Zimmer's original music, and it's a remarkable score. Just amazing.

I'd look forward to your next 25 years when you live to 110. Maybe we can do a reprise of this conversation. We'll check in on that. Let's see how you've been coming along, dude. Thanks a lot. Great to see you again. Thanks. This has been a special conversation, exclusive one-on-one between Star Talk and Kip Thorne, Nobel Laureate. Even let me touch his medal. This time I've ever touched a Nobel Prize.

Well, the medal that really belongs to a thousand. The medal earned by a huge team as he humbly declares. And as we enter a new era of science, where collaborations are really how this works, especially where you have international collaborations, if scientists getting along, even at times when the leaders of their countries are in conflict, that's just messed up. That's messed up.

I'm Neil deGrasse Tyson, your personal astrophysicist for StarTalk. As always, I bid you. We keep looking up.