StarTalk Radio - Relativity Round-up: StarTalk Live! With Janna Levin

Episode Date: November 7, 2023

Is the universe infinite? Neil deGrasse Tyson and comedian Paul Mecurio go to infinity and beyond as we explore the origins of relativity, time travel, and the discovery of expansion with astrophysicist Janna Levin, PhD live from Pioneer Works in Brooklyn.NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here:https://startalkmedia.com/show/relativity-round-up-startalk-live-with-janna-levin/Thanks to our Patrons Shari Murnane, Gary, Eoghan Smyth, Dmitry Petrov, Paul Dragicevich, Elizabeth Flores, Joseph Russomano, and William Riley for supporting us this week.Photo Credit: ESO/VVV Survey/D. Minniti, CC BY 4.0, via Wikimedia Commons Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

On this episode of StarTalk, it is StarTalk Live at Pioneer Works in Brooklyn. My comedic co-host is Paul Mercurio, and our special guest is cosmologist Jana Levin. And we talk about my latest book, co-written with our longtime senior producer of StarTalk, Lindsay Walker. We talk about Einstein's greatest blunder. We talk about Hubble, Edwin Hubble, the man, not the telescope, and a lot more on StarTalk. Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now. Tonight, we have our friend and one of my favorite comics around, Paul Mercurio.

Paul, come on up. Where are you? Paul. Good. Paul, you got a podcast of your own. I do. And it was creatively called what? It's called, see, he's insulting the title of my podcast already. Inside Out with Paul Mercurio. Inside Out with Paul Mercurio. Okay.

I've been a guest on his podcast. And we had a great time at the Planetarium. Yes, we did. Yeah. Yes, yeah. And then a few drinks and we broke a couple of things. But no. Yeah, my office is.

So thanks for coming on. Thank you for having me. This is a live thing. This is an amazing space. I've never been here. This turnout's amazing. I'm really excited. And then we're all going to go swimming after this, just right?

Well, in the East River here. Yeah. So you have a new, you can sit down. You have a new off-Broadway show? I do. It's called Permission to Speak. And we were doing it off-Broadway and we're bringing it back. As COVID, the premise of the show is

we're kind of nameless and faceless to each other. But if we share stories, we talk, we connect, and we realize we have more in common than we think. And it's produced by Frank, directed by Frank Oz. So we're taking the show out again and we're really happy and excited about it. It's not a stand-up show.

It's about you guys. Interaction. Love it. And connection. Love it. And you've also written for The Tonight Show and excited about it. It's not a stand-up show. It's about you guys. Interaction. Interaction and connection. Love it. And you've also written for The Tonight Show and The Daily Show. Yeah, I was on The Daily Show for a long time. Yeah.

You got good chops in the business. Yeah, I carry Jon Stewart. That guy. Yeah. Oh, he's in. That's all me. No. And then The Colbert Report.

And now I work on The Late Show with Stephen Colbert. Stephen and I go back. But yeah. Okay. But I always say about Neil, I repeat this, his enthusiasm, if I had him as a science teacher, I'd be doing science today.

He makes it relatable, but his enthusiasm and his passion, you know, I had a guy with a cigarette, literally a cigarette hanging from his mouth. Alright, here's how you make a battery. He didn't care. But he's an amazing person. I got to know him through the show. So thank you for having me. But then, if I were your science teacher, we wouldn't have you as a comedian.

Oh. See, you got to ruin everything, don't you? All right. Next up, we all know and love her as Janice. She is Professor Jan 11. Janice, come on up. Jan 11. Jan 11.

Tao Professor of Physics and Astronomy at Barnard College of Columbia University. Where we first met. It is. And you're Director of Science here at Pioneer Works. Editor-in-Chief of the Pioneer Works podcast. Author of How the Universe Got Its Spots. One of my favorites.

Black Hole Survival Guide. And also one of my favorites, The Black Hole Blues and Other, and also one of my favorites, The Black Hole Blues, and other songs from outer space. That's how you want me to say it. All the time. I want you to say it all the time. The Black Hole Blues.

And so, in fact, tonight, we are going to focus on the fourth section of the book, which is really where the title of the book takes shape, to infinity and beyond. Places where our bodies can't go, but our minds can. So let's begin here right now in Brooklyn. All right, so in the book, it's about upheavals in our understanding of how the world works and how we reacted to that. Were we elegant and graceful,

or did we get dragged into the future kicking and screaming? Not all stories in the history of science have smooth, sort of journalistic, oh, burn the midnight oil and say eureka at the end. So let's detail some of the weirdest, wackiest ideas in the universe. And you've got to start with who? Einstein. That was just a good

guess. Yeah, so his special and general theory of relativity. And you're an expert on that, right? Oh, absolutely. Yeah, just checking. So tell us about Einstein's biggest blunder. Oh, yeah. He called it's biggest blunder. What's known as his biggest blunder.

He called it his biggest blunder. He himself. And we talk about this in the book just because this is some of the fits and starts that we go through to understand the universe. So what's going on with this? I love this about him because here he is dreaming these dreams that defy everything everyone else took for granted. But then he has a moment of like resistance

and it's emotional resistance. He wants to believe the universe is permanent, that it didn't have a beginning and it won't have an end and that it's like static. He wants that. That's an emotional response. And even in his own mathematical theory, he's surprised when other people study it and tell him it predicts a

beginning of the universe and an end to the universe. His own theory. His own theory. He couldn't handle it. He couldn't handle it. He couldn't handle the truth. He couldn't handle the truth. But maybe he just was exhausted at that point. He's like, I've done all this. I know some of it's wrong, but I need a year off. I need some drinks. Maybe that was the issue for the guy. Well, crazily enough, the guy almost can't be wrong even when he tries. So he introduces what he calls the cosmological constant, which is just a term that's mathematically consistent

with the general theory of relativity. But he declined initially to include it because it made no sense. It came out of nowhere. He couldn't explain it. He couldn't explain it. He couldn't justify it. But what it allowed him to do mathematically was precariously balance the universe so that it was static. But it was very, very unstable, Iso. And when he realized that, he was like.

Right. So just so people are on the same page, I know you guys are scientifically literate here, but just to make sure, you can balance a marble at the top of a hill, and that's a point of equilibrium, but it's not stable, because any gust of wind will send it one way or the other. Yes, and in this case, the gust of wind would set the universe contracting or expanding.

Whereas if the marble were at the bottom of the hill, it's also a point of equilibrium, but it's stable because you can displace it and it'll always return to that spot. And that's what he was hoping for. He was hoping that if you tried to make the universe expand or contract, not be static and permanent, that it would actually prefer to stabilize. But it doesn't. It's actually very, very hard to stabilize the universe. And as we know today, the universe is, in fact, expanding. So Einstein was an idiot, you're saying? Yeah. But what was it? I mean,

there's a quote in the book where you say, with the notion of a static universe firmly anchored in its philosophical substrate, Einstein developed a general theory of relativity, and it embodies his assumption of a stagnant universe, even though his own equations reveal the unsettling truth. So he must have known. Why couldn't he get his head around that reality? I think that's, nobody really knows. I don't know if there was really a sense of investigating with him why he was so resistant to the predictions of his own days. But can it be really his fault? Who would have been the first to say, the universe has a beginning?

I mean, religion said it, but scientifically, there's no reference frame to even have that thought. No, it's really stunning. It's the first time there's a scientific concept of a beginning, a big bang. Listen, I think it's clear the guy was closed off emotionally. You got the analysis. So tell me about Lermont.

Yeah, so a physicist, and there was also a Russian. There were others. But they looked at Einstein's equations. Let's assume that there's a description. He's a Catholic monk. Yeah. Sorry, I forgot that important part. Yeah.

He's a monk, a physicist. Monk. Put that on your business card. Talk about closed off emotionally. Wow. There's a whole, thank you. It's one guy's getting everything. The hell with the rest of you.

No, but that's some kind of business card to have. Yeah. It's one guy's getting everything. The hell with the rest of you. No, but that's some kind of business card to have. Yeah. It's amazing he kind of made it into the canon, really, that he wasn't just sort of forgotten and excluded. He's studying this and he says, you know, if I imagine a universe where everything is kind of smooth and uniform, the whole universe, and I ask, how does space and time respond to a universe full

of stuff, as long as it's kind of smooth? You know, it's a very simple system, but not that far off from actually what we observe. But he realized that in response to a universe full of stuff, it wants to either expand or contract. All right, so... It doesn't want to just sit there. So did he finally agree to this? I'd say, yeah. He agrees after Hubble in the 20s...

Hubble the human being. Hubble the human being, after whom the satellite is named. Yes. Hubble looks out at a smudge on the sky and he's not sure what it is and he's trying to figure out, is it a nova, which would be a nearby object

that's very bright, or is it a distant galaxy and much brighter and much more distant? And there's an actual photographic plate that he took where he crosses out NOV and he writes VAR with an exclamation point, a variable star. photographic plate that he took where he crosses out N-O-V, and he writes V-A-R with an exclamation point, a variable star.

And it makes him realize, because of his understanding of variable stars, that it's a bright object far away. Very far. And that's based on Leavitt, right? Henrietta Leavitt's work. Henrietta Leavitt's work. Yeah, exactly. Henrietta Leavitt classified this variety of variable star

that turned out to be crucial to understanding the distances to objects. Leave it to a woman. There you go. Made it happen. Good job. Great, unbelievable story, actually, about Henrietta Leavitt and all that whole crew of female astronomers around the turn of the previous century.

They were called Pickering's harem because Charles Pickering, who was the director of Harvard's observatory, hired them for 25 cents on the dollar after he fired all of the male astronomers because they weren't doing a good job. And he said, my Scotch maid could do a better job. And he hired her, which is Wilhelmina Fleming, and she hired all these women, and they became this cluster of phenomenal observational astronomers, unsung heroes. They died in poverty, penurious. And there's a book highlighting their careers.

Yeah, Dava Sobel. Dava Sobel, that's right. Called The Glass Ceiling, I think. No, no. The Glass Universe. That could be. No, no. The Glass... The Glass Universe. The Glass Universe. That could be it. Thank you.

Yeah. We had David here to talk about that book. Yeah. And it's an incredible story, but Hubble knew about that work, which is remarkable. If he did not know about these unknown women and their work that they were doing

at the Harvard Observatory, he would not have understood that he was not looking, you know, if you just imagine a light bulb up close, that he wasn't looking at something up close, but he was looking at something much, much brighter that was very far away. And so we are now in the centennial decade of Hubble's major discoveries, as well as the centennial decade. We are, exactly, it was 1922.

Yes, exactly, of most of the centennial decade. We are, exactly. It was 1922. Exactly. Of most of the discoveries of quantum physics. So that was a watershed decade right there in the 1920s. so fast forward to 1998 and we discover a value for einstein's constant that's that's insane it's insane so this is what i meant he can't even make a mistake so he introduces this thing to try to make the universe not expand. Hubble comes along and says, I saw this galaxy.

It's really far away. And then I saw a bunch of them and they're all moving away from us. The universe is expanding. The whole universe is expanding. The whole universe is expanding. We're not at the center. We're just part,

we're also moving away from everything else. It's the whole thing's expanding. And then that calls into question the age of the universe and if any of those numbers are right and thing's expanding. And that calls into question the age of the universe and if any of those numbers are right and all of that. And we find out that not only is the universe expanding, it's accelerating by the power of this term in Einstein's equation. So in fact, the term does exist.

So even when Einstein was wrong, he was right. Exactly. So everyone's like, Einstein, get rid of that constant. It's a big blunder. And he's like, oh, my biggest blunder. And then in 1998, long after Einstein passed, they realized, oh, actually, the only thing we can think of, not just to make the universe expand, but to make it expand faster and faster to accelerate, is the cosmological constant, his biggest blunder.

Okay, so if we're expanding, that means yesterday we're smaller than today. And the day before, smaller than that. And I'm shrinking then. And if you go back in time, there's got to be a point where the whole universe is occupying one spot. It had a beginning.

Oh my gosh. That's Lemaitre coming in, which is actually very interesting as a monk. I wonder why Einstein was more resistant to the idea of an expanding universe than a Catholic monk who had to confront the idea that the universe was ancient and had

a beginning. Right. I mean, I think that's quite amazing. The beginning part was easy because Genesis is a beginning. Right, but not 6,000 years ago. 14 billion years ago. Yeah, billions of years ago. So if it is a beginning. Right, but not 6,000 years ago. Yeah, yeah, yeah. 14 billion years. Yeah, billions of years ago. So if it had a beginning and it's expanding, does the universe have an edge? And by the way, these questions, is that any different from sitting here on Earth and saying, how do I get to the moon?

I don't know. Pose the question. And you heard in this exchange that the answers to the theories had to wait for experiments to join the conversation. You can't just sit in an armchair and claim you fully understand the universe. So does the universe have an edge? Are you asking Paul or me? Paulul does the universe have an edge i think it does i've been to the edge and uh it's the hamptons and some people have edges yeah a lot of rich people with an attitude and uh i walked away and uh all right so what in the context of this in the book you talk about the human ego right and there's an interesting concept there that I thought, which really sort of surprised me.

And what you say is that given the battles that raged, et cetera, et cetera, you say, we know the universe is expanding, blah, blah, blah, the ultimate defining barrier between space and well-known space. However, yeah, there's a lot of stuff. By the way, the book needs more pictures. You know, it's like, look, a spaceship. No, it's a great book to fall asleep. And I think I'm never coming back on this show again. So, no, so in all seriousness, this is a quote from the book.

We know the universe is expanding and that expanded from a single point. Furthermore, everything in the universe must obey a speed limit. Reason would dictate that the universe must therefore have an edge. However reasonable though that might sound, it arises from a faulty premise,

driven in part by the human ego. And I was fascinated to know what you meant by that, driven by, in part, by the human ego. Well, ego, just are you in the center of everything? The authentic center? If you learn you're not in the center, can you deal with that? Can you handle? You can.

Because, no, just think about it. And we detail this, once again, in our ascent from Earth into the solar system. You say to yourself, we're in the center. By the way, we make calendars not knowing, calendars we still use today, not knowing Earth went around the sun. Yes, but they're adorable. They have puppies on them.

No, no, they're all good. So you can deduce a whole lot about the world without telescopes, but one of the things you cannot deduce is that Earth is going around the sun. That's messed up. Okay, that meant we went thousands of years thinking we're in the center of the known universe, fully feeding our ego. But why wouldn't you? And when there's no proof of anything else, in all seriousness,

what other premise would you, would you? Yeah, you're being too hard on, you know, pre-BCE civilizations. What are the issues that you have inside of you? Yeah, Neil. Yeah. No, what I'm saying is. You need a hug.

The whole universe. Come here. You need a hug. You need a hug. The whole universe is masquerading as a system centered on us. And so we're not given reason to question it because it feeds our ego. When something feeds your ego, you say, yeah, that's probably true. Not asking, well, maybe it's not true.

Because maybe it's not true could have the result that you're not in the center. But think about the ego you have to have as these great astronomers and scientists to say, I'm going to go and look into something that no one else has done and then stand by it and believe in it before anyone else does. That's not ego, that's curiosity.

No, but you've got to have an ego to stand by something, I think. No, yeah, no, then you're stubborn. I, but you've got to have an ego to stand by something, I think. No, yeah. No, then you're stubborn. I'll fight you right now. Yeah, if you have an idea and you stick by it, regardless of the data, go home. That's not what science is about. That's what Einstein did.

Which is why we discuss not having debates over science. Because nobody, no scientist worth their salt salt wants to come in with a notion and be unyielding or unwilling to accept a new idea or adopt it when it's clearly right. So two scientists in an argument, there's a different contract between them than there is between two people debating on a stage. Absolutely. So that contract is either I'm right and you're wrong, you're right and I'm wrong, or we're both wrong. So we'll argue until we get to the edges of what our data can show. And then we say, you know, I think we need better data.

Let's go have a beer. Right? Said no one ever at the end of a political debate. But the idea of the infinite universe kind of fell into that category because when Einstein was first writing things down, he was just doing the first pass, so to speak. And he has a famous quote where, you know, he assumed the universe was infinite, but he also assumed it was static.

And he said something to the effect, only two things are infinite, the universe and human stupidity. Yeah, best quote ever. And then he added, and I'm not so sure about the universe. That'sity yeah best quote ever and then he added and i'm not so sure about the universe that's right i forgot about that is it isn't it a matter of the observable edge versus there's an observable edge for sure so we can only see as far as the light has had a chance to get to us but it's not a physical edge of the universe it's not a physical edge you can't you can't drive through the universe and say,

the universe ends here. Well, we don't think so. We're not actually 100% sure. We don't believe that there's an edge any more than there's an edge to the earth. To the surface of the earth. So there's not a sign, welcome to the edge of the universe. Right. So, you know, if I travel from New York City and I go in a straight line, I don't fall off the edge of the earth.

Right. There's no edge. I make my way all the way around and I come back to New York City again. And that's actually a really valid model for a universe that is finite, not infinite, in which you go into a spaceship, you leave the earth, you travel in a straight line, you go out of the galaxy, you don't deviate, and you find yourself approaching the Milky Way again

with the earth in front of you. And you've never fallen off the edge of the universe. It's completely contiguous, but it is finite. So I have to repeat a quote from one of my earlier books. The universe is under no obligation to make sense to you. Hey, I'm Roy Hill Percival, and I support StarTalk on Patreon. Bringing the universe down to earth, this is StarTalk with Neil deGrasse Tyson. So let's get back to Einstein's theories of relativity.

Tell me about the intersection of time and space, which feels so unintuitive, but actually we exist. This way, the example I give is if I say, Oh, Janet, I'll meet you tomorrow at 10 o'clock. What's your next question? Where? Where? Sorry. Where?

I gave you a time, but I didn't give you a space. I'd say, are you bringing wine? So then I say, Paul, I'll meet you tomorrow at Starbucks. Okay? We know which Starbucks. And then you'll have to say? What time? What time?

So we know this intuitively. So then Einstein stitches them together. Why do people lose their mind? Well, I mean, it's amazing because a lot of things he did were actually really simple and intuitive. But he pushes it much farther where many people would start to get flummoxed and give it up and just be happy to meet at Starbucks with a bottle of wine. That doesn't really make any sense, but okay, Paul.

Always go to home with a bathroom. You can do whatever you want. So he starts to think, well, you know, I can draw up and down, north and south, east and west. Why don't I just also draw a dimension called time and then we can just agree on where we are in space and time.

And then he kind of pushes that further and further and further until he starts to say, oh, it's a space-time. And it's surely- As one phrase. One phrase. Space-time. I don't, right, I can't,

I don't like editors out there i don't like when you put a dash in there it's space time and no no paired words have to evolve yeah and and then they eventually lose their hyphen okay but like percent used to be two words then it was hyphenated in french it is but why don't you like the hyphen? Because it separates space and time in a way that Einstein was trying to transcend. And in this book, we did not use a hyphen. We have editors that followed suit here. So we got National Geographic editors.

That's a National Geographic book. Okay. So what that means is that if time is a coordinate, it can stretch or shrink. So you have different rates of time. Christopher Nolan did that in the movie Interstellar. Yeah, which was by our friend.

The original treatment was by Kip Thorne. Yes. Who's going to probably come up in conversation today. He's your counterpart at Caltech. Yeah. Yes. Well, that's a compliment. Thank you.

I'll take it. Totally. No, Kip was one of the most gracious, you know, elder statesmen of science when I first met him. And they made him an executive producer of Interstellar. So that meant you knew the science

had some backbone. And then he won a Nobel Prize. Really weird order of things. Yes, yes. Chronologically weird order of things. Behind that Nobel Prize, the real person was Matthew McConaughey gave him all the information.

He's a brilliant, handsome man. The person behind the Nobel Prize, yes. He'd hang out in his trailer and Matthew would be like, no, man, that's not how you do it. Wait, wait. So you have, if you're near a significant source of gravity,

your time frame slows down relative to other people. Yeah. That's freaky. It's very freaky, but in Einstein's language, it's no more freaky than the fact that my left and my right are rotated relative to your left and your right. In Einstein's language, you can rotate space and time differently than somebody else's notion of space and time.

In a four-dimensional coordinate space. Yeah, in a four-dimensional space. Yeah, that's really easy to grab there. That, you know, when you're near the black hole, it's as though you're rotating in space-time, just like you could rotate left and right relative to somebody far away. And just as I won't be like, my left is an absolute notion. Obviously, I'm rotated and it's relative to your left. If I face you, that's my right.

Exactly, 100% rotation. And he says, as you near the black hole, you have 100% rotation of your space, if you're far from the black hole, with my time that's near the black hole. It's just like my left being 100% rotated into your right. That's near the black hole. It's just like my left being 100% rotated into your right.

That's freaky stuff. Yeah. All right, so what about wormholes and whether we can use that for time travel? That's Kip Thorne. Or maybe it's Matthew McConaughey.

I'm not really sure. I don't know. Can we do this without a DeLorean? Yeah. Which is now, by the way, on Broadway. It's Back to the now, by the way, on Broadway.

It's Back to the Future, the musical. Now on Broadway. Yes. You really said that as though you were promoting. He's got a piece of the act. Just a quick point there to your space-time. I'm just going to slip this in because we have it in the book. If you go in a time machine,

I want to go back three days. So you go in and then you step out and it's three days earlier. You would be in the vacuum of empty space because Earth is in a different place. But why is it empty? It's still Earth. Why are you in a vacuum?

Because Earth is in orbit around the sun. And the atmosphere went with it. Earth is, you just went back in time, but Earth was in an orbit. You go three days back in time, you didn't say, keep me on Earth and do that. And the whole solar system moved. So if you actually want to go back in time and show up on this stage, you have to go back in time and in space so that the Earth is where you need it to be at that time.

So the space-time thing is real. If you want a time machine your way around the galaxy. Now, they got around this in Back to the Future because he jumps into the car, quickly types in a thing, and he goes back exactly 30 years. So he's in the same orbit. The Earth would have been in the same spot in its orbit. But did he also calculate for the fact that the whole solar

system is rotating around the center of the galaxy? For 30 years, no. He left that one out. You got to give him a hall pass. They got one of those right. But what is magical about 30 years in that scenario? It's just... Because it goes... Any years. No, no. In that scenario it goes from 1985, the year of the

film, to 1955. Right. Which is a very fun setting to put a movie in. Okay? Because teenagers are coming of age. So... Chuck Berry's music gets stolen. It's a great thing. Oh, Chuck Berry's music.

Do you know... Are we speaking... Who has not seen Back to the Future? Okay. A hand went up. Security, could you take this person out? No, just a quick point about Chuck Berry's music. Marvin Berry, the

brother or the cousin, okay, hears Marty play Chuck Berry, but that song isn't written yet. He holds up the phone for Chuck Berry to hear Marty play this Johnny B. Good. Was it Johnny B. Good?

Yeah. To play it. And he says, Chuck, this is the sound you've been looking for. Okay. So holding aside that it credits a white person for giving music to a black. Holding that aside. Which is exactly what I was going to say. You're holding a lot aside.

That's a tsunami. Holding that aside. There's something called a gin particle. You know about gin particles? These are things that are neither created nor destroyed. And they involve the time continuum. It's a loop in time where that song in that movie was never written. It only existed to be handed into a time loop and we call it gin particles because you can hand a person something that you then give to me later in time and that was never created nor it

was no but when she hands you that later in time you can't say that it wasn't invented previous no because i go back in time and give it to her. The time travel enables gen particles to exist. So this is along the lines in the book where you talk about sort of you go back in time with a spaceship and just before you're about to leave, the day before you blow up the spaceship, right? And then you've got… I wouldn't do that, but yeah, go on. Yeah. Well, it's in your book, sir.

No, it's a scenario. Go on. And where you're talking about parallel universe, right? And sort of how things break off. Yes. Right? Yeah, that's right. So how do we, how does, can we travel backwards in time authentically?

Well, this is all interesting related to it because you're assuming that the person who traveled back in time could make a choice that was inconsistent with the physical universe in which they live. Yeah. Right. that was inconsistent with the physical universe in which they live. And Neil, you saying, well, I wouldn't do that is actually kind of close to the bone because it's really the presumption that we have a free will that could do something

that defies the laws of physics. So you can completely go back in time as long as you don't exercise any free will that deviates from the consistency of that universe. That's what you call in the book, the butterfly effect, right? Like you go back in time. Right.

And then you start this sort of ripple, right? That could then change all future events. Right. But you don't have the option to do that. Even if it prevents the birth of you, who then went back in time. Wait a minute. Let's back up. Wait, what?

So my favorite example of this is I see a friend of mine walking down a corridor, and they slip on a banana peel. Okay. And they get hurt. I don't want my friend to get hurt. So I pull out a new texting service that uses particles that travel backwards in time, tachyons. And so I send a text backwards through time so that my friend receives the text before it steps on the banana peel, and therefore they don't fall.

So I do that. But what if he has his phone on airplane mode and doesn't get the text? Well, let's find out. So I send the text back. My person feels the vibrate, picks it up, looks at it, and it says, watch out for the banana peel. But while they're looking at it, they don't see the banana peel, and they slip on it. So the very fact that I sent the message back in time is what caused the slippage on the banana

peel. And so that's the temporal event laws of physics that you're referencing. Strictly speaking, the laws of physics, we know that general relativity has universes hypothetical, not ones that we've yet observed, in which you can do exactly what you just described, go back in time. But there is no law of physics that we know of

that allows you to do so in a way that is inconsistent. That prevents you from existing. With the exact path that you are on. So the idea of being able to alter my future by going back in time is... It's very 12 Monkeys. Yeah.

Ooh. 12 Monkeys? Yeah. You don't know. You're giving people a hard time about... I know. How did you miss 12 Monkeys? I remember.

I saw it, but I forgot it. Somewhere in between now and, you know, back to the future. Yeah, I forgot it. Sorry. But could that be wrong? Could what be wrong? Yes, it could be. Could that be wrong, right?

So there was a refinement of the process to figure out the age of the universe, right? Something that started 3 billion and then 5.5 billion or whatever. And to this day, right? There could be some new science that gets discovered that makes this inaccurate, right? What we believe now.

Or some time science. So there's nothing absolute. That remains to be discovered. There's nothing absolute. Never, never is there. Other than Neil's handsomeness, there is nothing absolute. That remains to be discovered. There's nothing absolute. Never, never is there. Other than Neil's handsomeness, there is nothing absolute. And even Kip Thorne,

who's come up a couple of times, who looked at this concept of wormholes. Wormholes were originally proposed kind of like, you know, the battery tunnel or something. It was a shortcut from one place to another. You know, or you go under the East River and you connect Manhattan and Brooklyn River and you get, you connect Manhattan

and Brooklyn, not that weird, right, to find a shortcut to get from one place to another. But what Kip Thorne did, which was exceptional, is he figured out a way to make that shortcut also traverse through time so that you weren't just traveling from a shortcut from one space to another space, so you didn't have to go the long way around. But you could actually go earlier in time. Oh. And they were time travel wormholes. They were time wormholes.

But I think if I remember correctly, you could not go back earlier than the time. Than when you were born. Oh, no. Than the time at which the wormhole was created. Oh. The weather you could go. So none of these things forbid the possibility that you could go back in time before you were born, kill your grandfather, the grandfather's paradox, before he had your mother,

and then you were never born. You don't have to kill him. You just have to prevent them from meeting. Well, this is kind of. It's so Terminator. Or slipping on a banana peel. Yeah, just... Or have them have sex 10 minutes later than they did.

A different person... Okay, now I'm throwing up in my mouth a little bit. Okay, no, sorry. Okay. It's actually very much like your banana peel story, because a lot of people think that the resolution is that if you went back in time and tried to kill your grandfather, you might just wound him.

And then he's so mentally disturbed that when he has your mother, she's tormented and traumatized. And you're so psychotic that you go back in time to try to kill him. What happened in both of your childhoods? So what you're saying is that the wormhole is like a doorway that has to exist

at that point in time or before that point in time that you want to travel back to, right? It was just Kip Thorne's idea for a way to make that happen without altering the entire universe, a way of doing it locally so that you don't have to think of an entire universe that violates, you know, time moving forward. But you could do it right here. You could make it like a machine.

We're still constructing the rules of time travel, is what this sounds like. Oh. Yeah. Yeah, okay. Yeah. Yeah. So, but traveling to the future, no problem.

Oh, yeah. I can definitely, obviously, we're all traveling to the future. We are in the future from where we were. At a rate of one second per second. Exactly. And none of us can stop it. It's really weird. I can stand still in space more or less,

but I can't stand still in time. So right now, this is the future. It's not the present. It's the present, but a second ago when we stood on stage is the past. We have traveled. We are prisoners of the present, forever transitioning between our inaccessible past

and our unknowable future. He went back in time and gave when you drop acid before a show. Alright, so... Wait, wait, can we just go back to that for one second? There is a present. Yes. Right now. Yes. And there is no future.

I can't say that. So there's questions like, is this like a hill where the future exists already and we're just traveling towards it, but it already is there, like a physical hill, or is it kind of unraveling

in front of us instantaneously? That's not a question we know the answer to. Is there a predetermined destiny that's scientifically based? That's part of that question. Well, you're not going to stop the expansion of the universe. I would call that a scientific future.

I would say that if it wasn't for the pretty big curveball of quantum mechanics, that the answer scientifically would have been, if not for that curveball that, as you pointed out, happened right at this time a century ago, absolutely predetermined from the second the universe was created us sitting here would have been exactly as it had to be quantum mechanics is a curveball but it's not a curveball that really saves us a lot so what is what is deja vu in all seriousness like we all had it right like we're in a moment where we go In all seriousness, like, we all had it, right?

Like, we're in a moment where we go, I remember feeling this thing or see, it just happened to me the other day, right? So is that somehow tied to this? Could one argue that it's tied to all of this? Now, George Carlin argued that he has Vujade, which is where he goes into a place and he's certain he's never been there before. Okay.

So that's me. That's right. So, I mean, to me, this feels in some way, I mean, you're nodding your head. Are you having deja vu right now? I am. I feel like I was in a place before where Neil was telling that joke. It's because we're on this terrible loop, Paul. We're never getting off of it.

Right. So we got to bring this to a close here. Oh, can we talk about the human ego? No, free will. You talk about free will in the book in the context of this. Yeah, that's a whole other level. Yeah, but it's a really fascinating concept. Well, then they have to buy the book.

Well, I'm helping you sell the book, buddy. Why don't you talk to them? I can't do everything, Neil. I can't write the book. He didn't write the book. to buy the book. Well, I'm helping you sell the book, buddy. Why don't you talk to them? I can't do everything, Neil. I can't write the book. He didn't write the book. Lindsay wrote the book. So, Janet, take us out with... Can you imagine a future of actual wormholes that we create

or warp drives, something to help us move across the galaxy with something other than chemical fuel rockets. Yeah, I actually can. Now, but it's been, it's really, so just like you build a bridge, you know, under the water between Manhattan and Brooklyn, you have to think about like- A tunnel.

A tunnel. Under the water. To me, they're all bridges. Wow, you just lost a lot of credibility with me. I'm not being a jerk, but I know the difference between a bridge and a tunnel. I'm the smartest one on this stage right now, everybody. Good night. So, you know about the spherical cow?

This is kind of like all physicists think anything that connects one thing to another is a bridge. Anything that connects one thing to another is a bridge anything that connects one thing to another is a bridge and um you think about how much energy money it would cost and how how to do it like what materials you would need so very similarly when kip thorne and people like that were talking about wormholes in space time they were like what kind of fuel would i need and they just made up. I know it has to have certain properties. It has to repel. It has to keep this open. And they, you know, made the wormhole great.

But then they looked at the fuel and they were like, we've never seen anything like this in the observable universe. So nobody knows of a fuel or an energy source that can do what the wormhole can do. But if we had that fuel, we could build wormholes. Well, that was my question. How does one make a wormhole? And it's very difficult to get contractors to do work. How long does it take to get someone before they give you an estimate and actually start on the wormhole? Time? You're asking me about the time? Plus, wormholes, as I understand it, are unstable. If you go through a wormhole, it can collapse on you

in a moment's notice. Right. That was a real problem, is it kept pinching shut and separating the two space times completely. And so you couldn't make it through without being crushed to death or annihilated. But doing that, you can make them stable again if you make up a form of energy that we have never seen in the universe. But it doesn't mean we never will see. I mean, Einstein's greatest blunder, you know, in 19, when did he,

1916 was general relativity. When did he write it down? Must've been that same year. 1917. 1917. And it was 19, I'm believing you. Okay, good.

Good. You wrote the book. Okay, good. No, I don't care. He is the smartest person on this show. Shut up. Wait. No, I was impressed. I made notes, buddy.

You didn't have to look at your notes. I made notes. Hang on a second. You just looked at me. You talk about the difference between bridges and tunnel. I'll be right back here, right? No, very... Paul, we're proud of you.

Real good. So, watch. So, so, so... The universe finds a way is all I'm saying. Okay. And it's not any different from going back 200 years ago and saying, in order to get to the moon, we need a fuel that has this amount of energy in it.

They would not be able to fathom that. And you pack all the energy into this tube and then you can reach, they would say, what's wrong with you? Okay, so that's what gives me hope that you can make a wormhole and we'll go right to you when we have the material.

And then that would completely transform transportation in the world. In Star Trek, you wouldn't need the transporter. Just open a wormhole and step down to the planet. Much less terrifying than having all your atoms reassembled. Of course, exactly. Is that doable at some point, you think? Transporters?

Yeah, to break down your molecules and put them back together. It's actually been done, technically. They have teleported a molecule from one place to another. I mean... A molecule. Taking the energy that it became... All of its facts. And put it over here.

Tossed them over there. Yeah. Yeah. And it appeared exactly as it was before. Now, we have a lot of facts about us. It's a lot more information. Than just the existence of the molecule. I know you two do. You got a lot of facts about us. It's a lot more information. Than just the existence of the planet. I know you two do.

You got a lot of issues inside. So just again, to round this, to close this out and land this plane, this rocket. So I look forward to a future, because that's the whole spirit of the book, where the next wave of what happens is beyond the reach of what we can even imagine building today. That's the beyond infinity. See, but this argues against your thing in all seriousness about sort of the ego thinking we're at the center of the universe. So when you were talking about sort of how they found a way to invent fuel to go to the moon, it was egoless.

It was actually the opposite. It was like striving to find other life, right? So it works against that argument, doesn't it, on some level, about that we're ego-driven? Wait, you're saying we are not ego-driven because of the example of the moon? I never said we were ego-driven. But I think the example of the moon is very ego-driven because it was very fueled by the Cold War when the Soviets put Yuri Gagarin in space for the first time. Americans panicked.

And they said, you know, the phrase... Translation, we lost our shit. We lost our shit. And that's when JFK came out and said, hey, space exploration is for all mankind. It was very ego-driven in that sense. So, I mean, we are what we are. We're a product of evolution,

and maybe the ego was important in our survival, and here we are. Or the fact that we can't be contained in a box. Which is also important for our survival. Indeed it is. I've always said that about Neil. You can control them, but you can't contain them. I don't know. That'd be the last words of this recording of StarTalk.

Join me in thanking Jana and our comedian, Paul.