Julian Dorey Podcast - #310 - Gravity Physicist on Intelligent Life, NASA & DARPA Anti-Gravity | Claudia de Rham

Episode Date: June 13, 2025

SPONSORS: 1) GhostBed: Use Code "JULIAN" to get 10% off your new GhostBed Mattress https://ghostbed.com/julian PATREON: https://www.patreon.com/JulianDorey (***TIMESTAMPS in Description Below) ~ Claudia de Rham is a Swiss theoretical physicist working at the interface of gravity, cosmology, and particle physics. CLAUDIA's LINKS: IG: https://www.instagram.com/claudia.derham/ BUY HER BOOK: https://www.amazon.com/stores/author/B0CJRZY58B?ccs_id=a0ca1502-30a1-46da-b05d-d7bb911d44f9 FOLLOW JULIAN DOREY INSTAGRAM (Podcast): https://www.instagram.com/juliandoreypodcast/ INSTAGRAM (Personal): https://www.instagram.com/julianddorey/ X: https://twitter.com/julianddorey LISTEN to Julian Dorey Podcast Spotify ▶ https://open.spotify.com/show/5skaSpDzq94Kh16so3c0uz Apple ▶ https://podcasts.apple.com/us/podcast/trendifier-with-julian-dorey/id1531416289 ****TIMESTAMPS**** 00:00 - Claudia Dreams of Equations & Making Sense of World, Gravity 12:23 - String Theory 18:21 - String Theory Revelation (Holographic Projection) 30:04 - Exploring Emmy Noether’s impact on physics 45:15 - What is Space & Time 52:52 - Black Holes 01:06:33 - Age of the Universe (Last Scattering) 01:19:08 - Meaning of Life (God Question) 01:26:03 - Growing Up Lack of Religion (Different Way of Thinking) 01:36:03 - Best Theory of Relativity & Universe, Dark Energy & Anti-Gravity 01:44:31 - DARPA Creating Anti-Gravity Science Theory 02:07:31 - Cosmic Dust 02:17:21 - Numerical Simulation 02:24:03 - Using AI in Science Today, Concept of Time (Time Travel) 02:35:19 - Astronaut Story 02:42:04 - Extraterrestrial Life 02:51:15 - Claudia's Projects CREDITS: - Host, Editor & Producer: Julian Dorey - COO, Producer & Editor: Alessi Allaman - https://www.youtube.com/@UCyLKzv5fKxGmVQg3cMJJzyQ Julian Dorey Podcast Episode 310 - Claudia de Rham Music by Artlist.io Learn more about your ad choices. Visit podcastchoices.com/adchoices

This is the way science works. Everything is space time. Once you start including acceleration or gravity in the game, space time takes some life of its own. When you get very close to the center of the black hole, the only thing I can tell you is that it'll just swoosh you to the center of the black hole and you have no choice on it. I can no longer use Einstein's theory of general relativity to tell you what happens there.

It breaks down. And some people come up with possibilities where this would be the bridge to something else. Do you think that something like that could exist though? A multiverse? Definitely. So what I can tell you is that we know there's dark matter. There's a completely different sector of matter that are living right here among us, doing all of those things. We wouldn't see them, we wouldn't smell them. All we would do is feel them gravitationally and we do feel them gravitationally in the galaxy and so a natural question was to ask ourselves... where do you

think it all comes from? do you believe in a creator? hey guys if you're not following me on spotify please hit that follow button and leave a five star review they're both a huge huge help thank you Thank you. Claudia, sorry for the long drive from the airport. It's Saturday. The Knicks are playing in the playoffs. It's a little crazy, you know. It was fun. It was fun.

Yeah, it was fun. It was good to be here. Nice nice fly. I flew all of South of Manhattan. Oh, so was good to be here. Nice, nice fly. I flew all over South of Manhattan. Oh, so you got to see it. Yeah, I got to see Liberty Island. Yes. Yeah, it was beautiful. Yeah. Thank you. It never gets old when you see that. You look down. It was really nice. I was on the right side of the plane. Well, I was on the left side of the plane, which was the right side of the plane. Yes. Yeah, you look down and I always think about it because we had the wallpaper here too,

but it's obviously not nearly as good as the sky. It's like, damn, we built all those things. It was crazy looking at it, you say, wow, there's so many of them. But yeah, it was good. Now in your world, does that exist or is space time not real? Well, we can use it up to some extent if we really have to.

We're going to get into it today because you're like one of those, like my brain explodes when I hear you talk. No, you're saying it's going to be fun. Yeah, you're like so you're so happy and fun about physics too. And yet you're looking at like the entire nature of reality. I don't know how you guys like sleep at night with that. Well, we get so tired thinking about all those things. We have no other choice, but I dream about it.

You dream about it? Yeah, I dream about it. And sometimes I start saying formula, G mu nu, T mu nu. Oh, you're dreaming about the formulas, not like the fun stuff. I mean, it's all built in. It's all, you think about, It's like Legos, right?

You're thinking about the structure and then the formula, you have to think of them as little pieces you put together. So sometimes, like, you have this little piece and you're trying to understand where you're gonna put it. So... If that frustrates me... And it comes to you in your dreams. Sometimes, in my dreams, it's always very clear. It's just when I wake up, it's not that clear anymore.

It's like an idea. It kind of like goes away, and you're like, wait, that was so good. What was that? I'm sure. Let me go back to sleep. I'm sure it's going to be fine. Yeah.

Yeah. So I actually, I got introduced to you through my friend, Kurt Jemungle. He was here last summer. Yeah. We did a really fun conversation on here. And I think we talked about you, I friend, Kurt Jemungle. He was here last summer. We did a really fun conversation on here. And I think we talked about you, I think on camera, but then we're talking about you off camera. And I can't even remember the context of it, but he was talking about like

how brilliant you were. And so I went and listened to the podcast you did with him. Yeah, we did a great podcast. It was fun. I think it was shortly after that. And I was just like, well, I don't understand half of this. So we're going to have to do this in this studio and bring it down to earth for me. No pun intended. Yeah, so he's a bit more technical. He's very technical.

Kurt's smart. He's great. He's amazing. So I did another podcast with him two weeks ago. Oh, you did? Yeah. I didn't see that. It just came out.

OK. I'm going to have to check that out, too. Yeah, Kurt's extremely, extremely well read on all this stuff. Yeah, no, no, he's up there. That's a very good endorsement, by the way. He should play that like for his reel, like Claudia Duran, he's up there.

But your work, your life's work has been centered on gravity and the nature of what it is. And a lot of us out there know the story about Isaac Newton and the apple fall and that's gravity. But we just think about it and take it for granted. It's the thing that keeps us on the ground. Yep, yeah, yeah, yeah. So that's right.

You're looking at it beyond that though, right? Yeah, I mean, one thing already with, we can start getting technical there, but one thing already with this story with Newton stuck getting technical there, but one thing already with this story with Newton, it's not so much about the apple falling on him and hurting him. And that's really funny. It's him realizing that there's a phenomenon here on earth, where we, it keeps us on the ground, it keeps us rooted, it keeps us there. But that's the same phenomenon and then dictates the lows of physics in the solar system. That's the

same reason planets are orbiting around the sun and making that extrapolation is really non-trivial. We take it for granted now, but realizing that something which we're experiencing right here on a particular scale is in fact exactly the same phenomenon that governs the formation of the whole of the universe. That in itself is an incredible realization. So the full universe and not just particularly like the galaxy that we exist in. So now we can go into the details but in fact the whole universe is, what is it, it's space time and so gravity is space time. So it is the whole universe. Gravity is really the fundamental law that governs anything that you want to think about. But for Newton, he was already understanding that just pragmatically understanding an apple falling towards the

surface of the earth. That's the same phenomenon as a planet orbiting the sun. And the planet is falling, it is falling, it is attracted by the sun and we have the impression that it's not falling directly towards the sun, but it's still feeling the gravitational attraction of the sun. It's just imagining I take a rock or let me take an apple and instead of just dropping it, I were to throw it and I'm not going to throw it very instead of just dropping it, I were to throw it, and I'm not gonna throw it very, very fast. So it's gonna drop in a little bit.

And if I were to throw it faster and faster, then it will start going further and further, to the point that if I was strong enough, I could throw it, and it would... the way it would fall, it would follow the curvature of the Earth. And so that's what being in orbit means. And so the team that just went on orbit, that just went into space for six minutes... Oh, like Katy Perry and all that?

Yeah, that's what happens. That's what they did. They... In fact, they're not... They're not experiencing something away from gravity. They're experiencing gravity. They're just falling. That's what falling is. That's falling. That's what you call it. So if you're thinking of an apple falling, or if you think of yourself falling,

just during the fall itself, you're not gonna feel anything. And that's the same thing if you're in orbit, if you're in outer space, and you imagine you're orbiting the Earth, that's what falling feels like, and it's just that fall doesn't stop. You keep on going and going and going, and that's just amazing.

It is. It's the greatest thing you can imagine. It's what keeps us alive too, because we're not falling actually into the sun. That's why. That's a good thing. Yeah. When did you first get interested in gravity? Like, were you just a little girl?

Like, I wonder why I'm standing on the ground right here, not floating. Well, I wasn't I'm standing on the ground right here, and not floating. Well, I wasn't really too bothered about the Earth itself. I was more thinking about the stars and the planets. So it was more trying to understand what's our place. What's the place of the Earth here in the solar system, in the universe? But I was very small, yeah.

But I think we're all interested in gravity, actually. I think you can, I can see you're interested in gravity. Yeah. I think we all play with gravity to start with. We all throw things around. We all try to see if it's gonna keep on falling down, keep on breaking down when you reach the ground. And I think so we all do that and just continue doing it rather than doing anything else. We all do it. But what makes you

question how it works? I think it's playing with it. I think I think we in fact, we we all sort of question it. And after a while, we take it for granted was I guess I never I never stopped taking it for granted I never I never ever stopped questioning it But I think we all sort of questioned it to start with we all take objects and then make them Fall down and say oh it's working. Let me try if it works again And it's sort of surprising that it works so well all the time How young were you when you started actually looking into the science behind it, rather than just experimenting and being curious?

Probably around 10, 12, something like that. But looking in the science behind it, it's more reading about it and understanding what it means. You don't need the math so much. You don't? Well, to understand the concepts, you don't need the math so much. You don't? Well, to understand the concepts, you don't need the math. Then if you want to actually interrogate things and make predictions, then you start needing to have formula and need to be more precise. That I don't think I ever did before I was a teenager, like everybody else.

I was going to say, that gets very complicated too. I don't think like at 10, you gotta be special at 10 to be doing something like that. But it's interesting because when you think about everything that we look at in the universe, it's all at its core. I mean, this is overgeneralizing, but at its core, so much of it is theoretical.

It's like, it's not like we were there at the Big Bang. It's not like we know precisely other than what we can estimate how old the universe is or how big it is, how many galaxies there are or anything. And the beauty of science is that the most brilliant people in the world right now, which you're among, years from now, much of your work will technically be proven like either wrong or it was on the right direction

and now we've expanded upon it. But you're a part of that never-ending search for truth such that you can, you know, you look at legends like Einstein where his work, things have been proven wrong, but he set the pathway for so many people after him to improve. That's why, that's why, that's exactly what I was saying. It's really a pathway and it's a journey.

And it's being part of the journey. And maybe your contribution isn't quite right. It's certainly not the end of the story, but we're trying to get somewhere. And exactly where we're going, we don't know. We don't know, but we're trying to understand, yeah. And of course, it's all theoretical. I haven't been in space.

I don't know that I haven't gone measure things in outer space, for instance. But we can have theories. It's instance, but we can have theories. It's theoretical, but we can make predictions. And from those predictions, we can say, this is what should happen. Now, I'm gonna start looking here, and I'm gonna make this very, very precise observation,

and this is what I should be able to see. And that's what we see. And people have detected gravitational waves. Can you imagine? People have said, okay, if this is right, what it means is going to have, I'm going to build some vacuum chambers underground and then I'm going to have some mirrors which are located four kilometres apart and we're going to have two set up like this, one on one side of the US, the other

one on the other side of the US and we we're just going to wait there. And every so often, they're going to shake around just a tiny little bit. And that's going to be a signal of gravitational waves, which is coming from the merger of two black holes located millions of light years away from here. And he's going to have some funding from that. And, and people build out and that's why they observe, you know, that when gravitational waves pass through the earth, they are stretching space between those mirrors in those cavities, which are four kilometers apart by distance, which is smaller than the size of a proton. And that's something we measure.

This is something we could predict, and we have measure. And the way the signal behaves is exactly as one would have anticipated. So all theoretical has been theoretical for 100 years. And then you actually observe it exactly the way you predicted it. It's cool when you can actually test it. It's amazing, it's amazing.

Right, but there's also, and I don't wanna, this conversation gets weird sometimes because it's almost like you discourage thinking about things and how things could be, but it gets difficult when there are theories that are so granular or so down to the core, no pun intended, that we don't have the ability to test them yet.

And then it creates a lot of problems. In academia, obviously, I've had a lot of people in here have talked about string theory on both sides of the issue. And I get it because they haven't been able to ship a test on that. But the concept, when you listen to Dr. Kaku explain it, the concept makes a ton of sense. It would make sense. That's right, that's right, that's right. You know what I mean?

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Not because I think it would be wrong. I think it's amazing. I think it's the most concrete potential formulation of what could happen beyond our understanding of space and time. So I think we should really take it seriously. But it would be so cool if there was a way to understand whether it could be wrong and what it would be so cool if there was a way to understand whether it could be wrong and

what it would mean. And when we say string theory has been disconnected from reality, I don't think that's entirely true. I think there's been a path that was given for some years and it hasn't materialized the way one would have expected, but it still relies on our understanding of how physics has to be realized in some contexts at very, very high energy. And that still has some consequences for things that we can observe within our experiments

that we can play with today, tomorrow. And so they are potential tests that one can do if we observe some specific values for some particle collisions or observations of cosmology or gravitational waves, it could be that we could have signs that string theory is not the right completion of reality. So it's not entirely true that it's completely disconnected to the way we can probe nature at the current state.

But what I think of string theory, I don't know. I think it's good to have alternatives. I think it's good to have a formulation. It's the best, I think it's the best game in time at the moment. There's not really any other concrete way to formulate things. The fact that it's very challenging to get some concrete observables out of it is disappointing, but that's sometimes the way it is.

But in the research that I do, I try to remain relatively agnostic in the kind of high energy completion, what happens beyond our frontiers of knowledge that we could have. And I think it's important to keep an open eye on all sorts of possibilities. We'll see. Yeah, I like your attitude towards this a lot, too, because it's been the issue, I think, in academia where the main arguments with string theory have come in are not necessarily to your point that people are coming up with these other theories that can compete with it or prove something better. I really haven't seen that. I know Eric Weinstein talked about geometric unity, which was a little controversial because he comes at it from the mathematical, as a mathematician lens.

But smart stuff, I'm not smart enough to speak on the evidence there, but it's like a lot of the issue is that, and I think Eric raises this point, is that there are so many string theorists and physicists who adhere to string theory, who are, you know, I guess passively, technically, like in control of academia in a way

that is almost discrediting opportunities for other theories to formulate because it's been so ingrained. And I don't even think all that's like corrupt or anything like that. I think it's just natural, like, oh, we've been studying this forever. We're trying to work to test it. So like you said, it's the best game in town

and people therefore who come into question it, it's more like, ah, we don't wanna deal with that. Do you think that's a fair way of putting it? It depends a little bit on who you ask. If you ask the people that are out working on string theory, some of them, they're actually quite open-minded, particularly nowadays. Some of them, they may not be too bothered about other things, and that's completely fair, I would say.

I think there are aspects of string theory that have actually been a huge success. Like what? Just for instance, the graviton comes out of it. And that's incredible. There's no other realization where you can actually understand how the graviton comes out of it. And a lot of the, you compute, when you compute some loads of probability, that's the way it works. The quantum world

works through loads of probabilities, loads of quantum probabilities, when you compute those within a current framework, particularly when you include gravity in the game, you typically get something that doesn't make sense, that becomes an infinite quantity. And string theory resolve that. And that in itself is remarkable. It actually gives you an answer that can make sense and that you could in principle trust. Now, there are different issues with it. Some of them, they come in with, for instance, extra dimensions, they come out with a lot of luggage along the way. And then you need to deal with all of this.

And this has been hard to actually understand how you can get the world that we are experiencing directly out of the box from string theory. And it hasn't been like that. In fact, you have so many different possibilities that come out of string theory that it's even difficult to realize why we should end up with the world we in as opposed

to anything else. But that's a slightly different question. There's still a lot of success from string theory. And so I think there's a there's definitely some value. It keeps working and making progress in string theory. But it is true that making the connection between string theory and a realization of the world as we see it, this is not something even a lot of string theorists are working on at the moment because it has been challenging to make progress in that. So a lot of string theorists now, they work on slightly different questions of string theory.

Like what? For instance, have you heard of holography? I don't think so. Okay, that's Okay. I'm not a strength theorist. I'm not an expert in holography by any stretch of my mind. Today you are. Okay. One of the cool thing that came up from strength theory is the realization that you can think of gravity, you can think of a system which is gravitational,

you can have black holes, you can have all of these really, really gravitational. You can have black holes. You can have all of these really, really cool things that come out of gravity. But in fact, all of the information about that is encoded on a projection. And a projection. It's a holography. It's a hologram.

Now the geometry of that is something you may not have heard of. It's called anti-de Sitter space. Definitely Now the geometry of that is something you may not have heard of. It's called anti-de Sitter space. Definitely haven't heard of that. So now you should write it on your book today. Yeah, we'll write it on the next book. I still won't remember it the next time, but keep going. So that's just a little sad, but you can have,

you can think of where gravity is as being a space time, which has a boundary. And the information which is on that boundary carries as relevant and can, from that, you can derive all the quantities that you want. You can derive all of the equivalent observables as you would want as compared to a theory which would have gravity in what we call the bulk or

the fully fledged Extra dimension thing so you can have a theory of gravity Which is in fact completely equivalent to another model with our gravity of fields Which may satisfy some specific properties with some specific symmetries in one lower dimension. So that's projection and that what we call a duality between that. And so that enables us to understand gravity.

In fact, not as a gravitational theory but as another kind of theory with which we have much more control off and with which we can make a lot of progress in terms, particularly in terms of calculations and particularly in terms of understanding what happens when the system becomes so complicated and interacts with itself so much that it's hard to keep track of everything it's doing and so you need to have a slightly different

perspective in how to look at everything. And you can do that. And people are even nowadays making connection between that and systems which are condensed matter system, like real physical system that don't involve gravity at all. And yet they have some description which are dual to gravitational theories and so you can have gravitational theories that involve black holes and And you can try to understand for instance how information Gets lost or would be restored when when a black hole evaporates. Wait, what do you mean by information?

Okay, maybe we should. Yeah. By the way, for everyone out there, every sentence Claudia says, I could technically go back and ask a question on it, but I don't want to ruin your flow, so there's some things we'll come back to. You can come back. Let me stop there.

We can go back to black hole information and all of that, because that's going to attention. But all I'm saying is that this is the way science works, right? You try to make progress in a particular direction, and maybe you're going to make progress into the question you were originally asking about. And you do have a much better picture of what could go beyond our understanding of space and time. For instance, in string theory or alternatives to string theory, but also along the way, you get up with all sorts of different understanding which you never thought would come out of it.

That's how you make progress and you need to keep on exploring. You need to keep on exploring all of these possibilities. So you do believe, if I'm understanding correctly, you do believe that regardless of the outcome of string theory being correct or incorrect, there are ideologies there that have been able to spark the idea of other things that actually might be provable here. That's right. That's right. And it's not so much of ideology. It's a scientific research is going forward into probing what is possible. The graviton part though. You said that came out of this too.

Yes. When did that happen? Can you explain the graviton to people? Because that's at the center of mass gravity and the things you work on as well. So it's going to be important to have that context. Yeah. So we celebrated 100 years of quantum mechanics. This year.

We did. I missed it. Sorry. Happy birthday. Yes. To understand the gravity, it's useful to combine a little bit gravity and quantum mechanics. But let me start with something slightly different, which hopefully is a little bit more familiar quantum mechanics, but let me start with something slightly different, which hopefully is a little bit more familiar, which is light. We're all familiar with light. Hopefully we're familiar with light. And light is a wave. And light is an electromagnetic wave. It's just a fancy way to say that there's a field, which is an electric and magnetic field. And when light comes from everywhere,

it's actually some vibration in this electromagnetic field. Light comes in with a particular frequency and carries some energy. In principle, the light in this room, you could say, let's imagine we just had light of one color. Now, this is light of multiple colors together, it's white light, but let's imagine we just had one color of light, one frequency of light, and you were to dim down the intensity of light in this room. They would come a point where you will start saying that it's not continuous. You can't completely dim down light to as much as you want. They will come

a point where you realize that light is actually carried not by something you can doubt at which, but in fact, by a discrete level of energy. So for light of particular color, we know that it's carried by particles, which we call photons, and those photons, they are the carrier of the electromagnetic wave. They are the

carrier of light. Photon, the particles responsible for electromagnetism. And you can even think, in fact, if you have two electrons or two charged things, so we all know of static, for instance, if I were to do static with my hair, whatever. Every morning I do that. I got to wet my hair. It's crazy. So you know about that. You know that there's some sort of force at a distance, and you can ask yourself fundamentally how is this force at a distance transmitted?

What is the carrier? What is the fundamental messenger of the static of the electromagnetic force? And fundamentally, it's a particle which is the photon. That's a fundamental particle, and we understand that very well. Now, the reason why I'm starting to talk about light and all of this is because there's a direct analogy with gravity. And the same thing exactly happens with gravity. There's an analog of light for gravity, which are- An analog of light? What does that mean in English?

So light is related to the electromagnetic force. Yes. And so that force, I can think of instead of the electromagnetic force, I can think of the gravitational force. OK. And so if the electromagnetic force, I can think of the gravitational force. And so if the electromagnetic force has... Trying to wrap our brains around it. Just keep going.

What are you doing? Trying to wrap our brains around it. Gio and I were looking at each other like, did you get that? Just like, nope. I'm like, just keep going. By the way, we have Gio Gus in the studio today, long time friend of the podcast, but please continue. Go ahead, tell me what you got. Still picking up the pieces here. It's going to start chilling NFTs if we let them keep going.

But you were saying the electromagnetic something or other and like. That's easy, no? That's easy. Then we'll have a scratch course on string theory and then we'll go on that. Yeah, we'll get there. Okay. Let me just say, if you think of electricity, if you think of the electric force, you know about the electric force, there's something that transmits the information between two electrons. If you know, they're gonna repulse each other Something fundamentally has to be there to transmit the information and fundamentally you can think of the messenger of that being the photon Now you can think of the same thing exactly for the gravitational force

You can imagine you have a planet and it's orbiting the Sun. How do you know what is carrying the information about that force at a distance, which is gravitational force? And so fundamentally, the carrier of the gravitational force, the carrier of gravity, is a particle, and that's a hypothetical particle. We haven't detected it, maybe we'll never detect it, but we do have stronger theoretical evidence. It has to be present. Why can't we detect it?

It's too small to be able to test? Yeah, the effect of a single graviton would be too small to have an effect which will go beyond Heisenberg and sanctity principle with current experiments. So it's too small, but yeah, it's too weak. It's far too weak. But yet we think that there is a fundamental particle

associated with the gravitational force. And so if you're thinking of the analog of light, the analog of light are the gravitational waves that have been observed. This is a shaking of those mirrors in interferometers. This is a passing through of gravitational waves. And those gravitational waves are actually, in fact, granular. We don't see that they're granular because the pieces of sand that would make those gravitational waves are so tiny. But if we were able to zoom in into the structure, we'll see that they're made out of tiny little pieces of energy, which we call gravitons. And so the graviton is the fundamental particle associated with the gravitational force.

And when did we come to that conclusion? How many years ago was that? So, Einstein's theory of general relativity, Einstein's theory of gravitation was in 1915. 15. 1915. And quantum mechanics came about 100 years ago. Very naturally, already by 1927, 1929, there was some understanding that the fundamental laws of physics were carried by particles.

So already by the early 1930s, there was some understanding that you could have such thing as photons and gravitons. Definitely by the late 1930s. It's been known that there were those fundamental particles. That's amazing that that long before like a computer, for example, they could come up. Like there were people smart enough, like an Albert Einstein and many other people who probably should have recognition as well

that could theorize something like this. And actually, even if they're not a hundred percent right or anything, they're in the right direction. Yes. It's amazing. Yes. Yes. Yeah. Who were your scientific heroes growing up?

Did you have any in particular? No, I don't think so. Yeah, I don't think so. I can tell you my scientific hero right now would be Amy Nerther. Have you heard of her? Who? Amy Nerther. Amy. heard of her? Amy Nerther? Amy, is it N-U-S-S-E-R? Last name?

N-O-E-T-H-E-R. That's her. Oh, she's dead. Oh, yeah, she's a bit dead, yes. I thought you meant like alive. Yeah, you want to invite her to your show. I was going to say, she's really dripping right there with style. That's like a real throwback.

Anyway, can we go to the bio? Let's give it a go. I'm going to go to the bio. I'm going to go to the bio. I'm going to go to the bio. I'm going to go to the bio. I'm going to go to the bio. I'm going to go to the bio. I'm going to go to the bio. I'm going to go to the bio. I want to invite her to your show. I was gonna say, she's really dripping right there with style, that's like a real throwback.

Anyway, can we go to the bio? Let's give her proper. All right, so Amelie Noether was a German mathematician who made more many important contributions to abstract algebra. She also proved Noether's first and second theorems, which are fundamental in mathematical physics. Noether was described by Pavel Alexandrov, Albert Einstein, Jean Diodon, Hermann Wey

and Norbert Wiener as the most important woman in the history of mathematics. As one of the leading mathematicians of her time, she developed theories of rings, fields and algebras. In physics, Noether's theorem explains the connection between symmetry and conservation laws. Translation, please. She's great. She rocks. She's got a resume. But what does this thing, she explained that she, her theorem explains the connection between symmetry and conservation laws. What does that mean?

Yeah. So let me say concretely, we all have this inbuilt notion that energy should be conserved. We sort of think that if I have a box in here and I have some energy, that kind of energy can change form. It can become mass or that mass can become heat or something else. But we like the notion to think that energy is conserved. That's what we call conservation law. And in fact, this is a luxury that we have in most of our everyday life, but it's not true in reality.

It's not true in the universe. We only have that conservation law, for instance, the conservation of energy, if there's a symmetry associated with it, and a symmetry is something which is, you can take a system and you can transform it, and it remains invariant. Do you see what I mean by that? Kind of.

It means things remain the same. And so if things were- Oh, invariant. I thought you said something different, okay. It's my English. Oh, no, your English is great. I just heard the way you say it way cooler. Say it in body.

And so I'm like, oh, yeah, in very bad. And yeah, you're in New Jersey. You got to bear with me. Um, so you have my English, your marks. And you know, good luck. Anyway, that last part, though, just repeat that one more time. So what was invariant again? I forgot.

What was invariant? Sorry, I did that to you. So you only have energy being conserved if the system itself is invariant. So in fact, in the universe, things are not the same as you evolve in time. You don't have that symmetry. By symmetry, we mean things remain the same, but they don't remain the same. Things don't remain the same as you evolve in time. The universe cooled down.

It became really, really very different, luckily. Otherwise, we wouldn't be there. And so we don't have this luxury of a conserved quantity associated with that. There's something else instead, there's a bigger level of invariance, which I'm not going to go into. And so other things are conserved. But what I mean, Nerther realized is how to make the link between what it means to have a quantity which is conserved, which we can rely on and won't change, and some symmetry system for which you can twig it, you can kick it, you can transform it, you can look at it in different ways, and it will

give you the same thing. Wow. Back in the 1920s and 30s. Oh, she was amazing. Yes. She's a mathematician too. So she's approaching it from a mathematical That's right. That's right. But, but her, her way she formulated all of that is actually the way we it's at the basis of our understanding of physics nowadays. All of our understanding of the constituents of matter and the fundamental forces of nature

They all nowadays based within a framework where her mathematical formulations and the conservation laws and the symmetries Inbuilt, you know in all of this It's very interesting and this is back. She's in the era where Einstein's first coming up with the theory of relativity That's right Yeah, so he has a huge respect of yes Yeah, I don't I think I don't even know that this make it complete justice to her because I think He considered her much more than the best female mathematician I think he really had a huge much more just a best mathematician in general possibly yeah yeah yeah it's clear I mean that's I don't know about her so I gotta you

should do some research yeah yeah I'll invite her on from beyond maybe AI will let us do it we'll have you sit in but what it's just just at a base level because it it formulated much of the work and I'm over generalizing level because it formulated much of the work, and I'm overgeneralizing here, but it formulated much of the work that you now work on today. But when Einstein came up with the theory of relativity in 1915, we throw around this term all the time, but for people out there who are like, yeah, I know what that is, but what exactly did he find? Would you mind just defining that? Yeah. So maybe to get there, sorry if I'm a bit slow, he did so many different things and it may be useful to go through

all the different things he's done. We know him, most of us know him through this formula, E equals MC squared. And so this already is incredible. It's a theory that make us understand how you can have mass and that's related to energy but it's much more than that and that's within the formulation of special relativity which was in 1905 and special relativity is a new understanding of how our perception of space, of the flow of time, and the notion of distances

may change from one person to another. This is something that hadn't quite been thought about before that. And the reason he was led to the formulation of special relativity, it's a different way to think about how we're experiencing the flow of time, was because of the realization that no matter who you were, no matter how fast you're going, you always seem to be observing that the speed of light in the vacuum, so if you take light and you shine it,

it travels at a given speed, which is super fast, but it's always the same, precisely exactly the same speed. And you yourself, you could be traveling at almost the speed of light, and you will still have the impression that light is traveling at the speed of light as compared to you. So you can never catch up with light, you can never do that. And that seemed to be content relative, this was counter any of the upper understanding of how, how the laws of physics should change when two people are moving with respect to one another. And so Einstein realized that, in fact, things had to be different fundamentally. And what was always the same was the speed of light. What was not always the same is how we experiencing the flow of time. There was something which was more fundamental,

which was invariant, which is the speed of light. And that you had to give away with our inbuilt notion that if you're experiencing one second passing by, I should agree on that. And in fact, we don't need to agree on that. But does that, maybe I'm thinking way off base here? But does that have to do with where we are not necessarily on on earth, but also in relation to space I forget the name of the experiment, but you'll you'll recognize it

I'm gonna go to space and time changes Yes, so that's a second effect which is related to the gravitational effect, to the curvature of space time, that's the second effect. But already in 1905, he realized that. And that's not to do with whether you close to a black hole or not, for instance, or whether you close to the surface of the Earth or far away. It's simply related to our respective speed

with respect to one another. So if you were to run a marathon at a constant speed, since the beginning of the universe till now, you've been running at the same speed, you would experience a flow of time, which is different as compared to the way I am experiencing it. It's very contentious, we think that's not fair,

and yet that's the way it is. What is fair? I actually don't understand this. So if I'm running a marathon. If you're running, you're just running. You are at a given speed with respect to me. We're not gonna agree on how much time has elapsed. Because we feel differently or because scientifically

there's a way that time elapsed in a different format? Because time is not absolute. Time is relative. Because like when I do a plank every day at the end of my workout, right? And I usually hold it for like 100 seconds. Yes. And it feels like fucking 10 minutes.

That's right. You're absolutely right. In fact, the more effort you make and the faster you run and all of this, the slower time runs. So what you feel is absolutely real. Okay. But is that, that's a different phenomenon that we're talking about?

Yeah, you're saying it's literally different. It is literally different. You can actually ask, you can you can ask yourself, you will feel different. But you can actually ask things like atoms, how much time they feel. And you can ask that because atom may decay through radioactivity for instance, they may decay and so they have an inner clock and the clock experienced by atoms will be different if they are at a given speed with respect to us. So those experiences have been made and you can have different, you can have the same material made out of the same atoms.

And then if you make some of them travel at a given speed with respect to some others, they will start decaying at a different rate because they feel a flow of time which is different. But does it revert back to the mean? And that's not the proper way to put it, but let me explain what I mean. The example you give of just like running a marathon into perpetuity, right?

Like that's not possible. You have to stop at some point. So like, let's say someone just runs an actual marathon, 26 miles. Yeah. And in your scenario, they're experiencing time in a different way. When they stop, they get across the finish line.

Now did the atoms almost go, whoosh, whoosh, suck back? No, they get across the finish line. Now, now did the atoms almost go? So, no, they don't, they don't. But the reason in 1905, then the reason I'm not starting to understand what happens when you stop is because then you need to understand what happens when there's an acceleration or deceleration, what happens when your speed changes. And in 1905, Einstein came up with the theory of special relativity, where the notion of acceleration wasn't yet built in. In fact, now we know that there's a come, what he knew, there's a complete equivalence between feeling acceleration and a gravitational attraction. And I don't know if it's, and a gravitational attraction. And I don't know if it's, you can feel that,

but if you actually try to feel what it feels right now for you to be pulled towards the surface of the earth, just feel how it feels on your bum, can you really tell the difference between that and actually what, in this room, for all I know, we could be in the middle of outer space and we could be in a shuttle pushing me in a rocket constantly pushing me with acceleration and I wouldn't tell the difference I don't know in fact what if I'm trying to think of what I would

would I be able to tell the difference it is not true I can't Meaning like if you were sitting within the object the rocket itself, that's all right pushing me. Yes, I'm pushing me The feeling would be I wouldn't be able to tell the difference. You can't it doesn't like pull you back to your seat like that But but you know, no that's so that's just a question of direction. Yeah. Yeah But the direction can be exactly the same and And but we know that. Oh, relative to the ground you're on. Yes. Got it. OK. So we all seen, I'm sure you can see some of those science

fiction movies where there's a cylinder, a rotating cylinder. And it makes artificial gravity in some of those, what is it? I know some of those science fiction movie, you know, you are in in this in outer space in the middle of nowhere, and you have this cylindrical. Oh, it's in like interstellar or it's just kind of like, yeah, okay. Can we pull up go to the beauty of interstellar on YouTube? Alessi, you can tell I've used it. Yeah, exactly. Exactly. That's right. Yeah, go to the top left one. Yeah. And if you actually can you go back for one second less? That one's a good

example. But I want to just check if I'm thinking of this right. See the one with the pink matter or like orange reddish matter up right there. Like that. Yeah, that was one. Yeah, yeah, yeah, exactly. So they're far away from anything. There's no earth there. It looks like there's just a cloud of dust or something like that. But let's ignore that. It's just for visual effect. So it's a round thing. And it's actually rotating so that people inside are being pulled out. And they do that so that they feel artificial, as if he was an artificial gravity from the earth. So there I don't know if you ever went to like an amusement park where they had this, but you know, like the grab it might have been called like the Gravitron. That's right. Right.

That's what before Gio and I were talking and I'm like, yeah, this lady works in Gravitron. He's like, it's Graviton. He was wrong. All day long, I'm going to. But that would it would spin you fast enough. And it's not going to like the maximum speed you go. But you'd be able to eventually like kind of like stand up. Exactly. Exactly. Exactly. So this is telling you that the acceleration can compensate gravity, or vice versa. So in fact, there's a complete equivalence between gravity

and acceleration. A complete equivalence. And there's a complete equivalence for an. Like they, I'm trying to think of this correctly, it's almost like there's an offset there. You can offset them. Yeah. Okay.

Yeah. You can compensate one for another or you can, you can, for instance, think that one is the other one. Just like now, because it's all dark in here. In fact, I don't know. You telling me that we are on Earth, but for all I know, you just shoot us out in outer space. Or we could be in another dimension. Michiu Kaku is like, if I just turn the transmitter a little bit this way, it could be a dinosaur in here.

That's a whole different, that's what scares me too. Like when we start talking about whether or not the dimensions are constantly like, overlapping with each other to an infinite degree. Yeah, yeah. I mean, that goes beyond gravity. That gets to like, wait, is this a simulation? Oh, that's just gravity. That's all gravity. That's just gravity too?

That's all gravity. Come on. It's all space time. All right, wait, define space time then. Space time? Yes. Do you know what time is? Yes, I think so. I don't know what time is. I don't know what time is? Yes, I think so.

I don't know what time is. I don't know what time is, so please explain me. It's a great song by Hans Zimmer. Okay, good. Do you have a song about space? No, I mean, like to me, time is just, it's the, I mean, it's hard to like say the definition without the word, but it's like the elapsing of a moment to a new moment, right?

But you guys, when you look at this, you do question it to your point where it's like, well, is that just a figment of our universal imagination in a way and time doesn't actually exist? So I don't even need to go into that. I'm happy to have time. I like, I like, well, I don't like time, but I'm happy to have time. Right. But it's it's relative in the sense that it is much of a muchness of what time is as compared to what space is. And we don't think of it like that in my everyday life. But if we are starting to travel quite fast, then we travel in time and we travel in space, and our notion of space and time can get

mixed in a little bit into one another. And so that's why we often talk about space and time together, because we can't really separate them both. They are wedded into one concept. Because it would technically not that we've been able to experiment with this literally ourselves, but it goes back to, again, not perfect science, but maybe like the idea that they paint an interstellar where you go far enough out into the universe, maybe you get involved with black hole, and the time that elapses for you could be 10 years,

but it could be 100 years here. That's right. Okay, exactly that. So this is exactly where we're going. When we had Einstein's theory of special relativity in 1905, That's right. That's right. That's right. Okay. Exactly that. So this is exactly where we're going. When we had Einstein theory of special relativity in 1905, he was just considering, for simplicity to start with, he was just considering speed, which would constant, constant speed. Now if you want to ask the question of what happens if I start running a marathon and

then I stop, I need to change my speed. And so that corresponds to acceleration and acceleration is the same thing as gravity. And so now really when we want to understand what happens in more realistic situation, we actually need to bring gravity in the game, bring acceleration in the game. And to understand that, we have to go even further in how we are thinking of a notion of space-time. In special relativity, the first thing is that space is not separate from time. They can mix into one another. So already there we see that it's something quite fun. It's really fun in itself and we can experiment with that. But once you start including acceleration or gravity

in the game, you're all seeing this picture, you actually see that space time take even some life of its own and can start almost moving, moving apart. And you can think of, you see in those pictures, for instance, the black hole on the, yeah, this, this you can think of it as space time. This is space time starting to be curved because there's a black hole in there. And so the understanding from Einstein's theory of general relativity,

which is a theory of gravitation in 1915, was the realization that when you start having masses or energy or anything which is non, that exists is non-trivial, then it actually makes space time come into life and curve. And it's not just all boring like a flat surface. It's actually something that has some curvature. And so to go from one point to another, it's actually not completely trivial. And now this is precisely

in this picture where the way you experience the flow of time is going to be even more different if you close to a black hole, if you close to something which is very curved like that as compared to what you're experiencing here on Earth. Now when you're saying curve though you're referring to the shape of say this black hole area literally. I'm referring in fact to the space time. The way I'm thinking of it and maybe this is what you're saying is you're referring to it almost like I'm picturing a curve on a chart, right? Like an X versus Y axis, where it's like, you would think time and space are supposed to go in a straight line diagonally up at a 45 degree angle. But as you move within space, it actually flattens out because you may be moving in the space at a faster or a slower rate than it is experienced during the base case of

time. Does that make sense? So it's not just in time. It's not just about what happens in time. It's really even what happens in space itself. But it's hard for us to represent it in our head. Maybe you can. I can't. It's very hard. It's very hard.

But so for me, curve space is, you can think of it just like the surface of a trampoline. And that is a curve space. You think of a trampoline, you put a ball in the middle, and you see that the fabric of the surface start becoming curved. Now, there's some issues with this analogy because the reason it becomes curved is not because so much of the mass being present in the middle, it's rather because the mass wants to get attracted to the Earth, and so that's what makes it curved. So the analogy is not perfect. And the analogy is also not perfect because space-time is not curved

within something else. Everything is space-time. There's not such a thing as something beyond space-time. Space-time is everything. There's not a point where as something beyond our space time. Space time is everything. There's not a point where space stops and then there's something beyond space time that doesn't make sense. So the analogy is not perfect, but you can represent the notion of curvature of space in the same way as we may think of how a fabric is curved. That's okay. But the thing is, now, I want to think of gravity, I want to think of the flow of time as well. You need to think of a space,

sorry, you need to think of a curved space time. And that I can't really represent it in my head. But it's true that when you are in different points in there, you will start seeing in my head. But it's true that when you are in different points in there, you will start seeing the flow of time being different in different points. And that's true. So in that black hole, if you're very close to the colored line, you're close to the black hole, the way your time will slow down as compared to someone which is very far away. So what is, there are a lot of elements in interstellar which are actually complete science. Yes. It's complete. I think like Kip Thorne was the guy advising on it. Yeah, yeah, yeah. And it's completely true.

What's probably not, what we don't know right now is how you could possibly go inside a black hole and then come out that we don't know. We haven't done that yet? Well, you can try. Send Katy Perry to do that. Okay. And she'll like it. Yeah. So when did we first come up with the concept of a black hole? Was that right around the same time? It was 1915. 1915, Einstein came up with Einstein's theory of general relativity. He didn't call it that, but he came up with Einstein's Theorem of General

Activity. He didn't call it that, but he came up with that. 1916, it was during the war, can you imagine? Right during World War I. Yes. And Schwarzschild was in the war. He was in the trenches. Churchill? Churchill. Yeah, yeah, yeah. And in there, he had nothing other better to do than do some little calculations.

1916, it was just a few months after the theory came out, just a few months during the war in the trenches, he found out black hole solutions. Churchill, Winston Churchill. No. I was on the same page. Schwarzschild. Schwarzschild. Oh, okay.

All right. I was like, wait a minute. How did I miss this? I'm sorry. I did not mean to do that. So who was, can we pull this guy up? Black Hole founder. So he was in, he was in the trenches and comes up with black holes based on Einstein. Schwarzschild. S-C-H-W-A-R.

I can't believe I'm in the trenches. This is a great science fiction movie. All right. So, Karl Schwartzschild, a German physicist and astronomer, he provided the first exact solution to the Einstein field equation in general relativity for the limited case of a single spherical non-rotating mass, which he accomplished in 1915, the same year that Einstein first introduced general relativity. The Schwartzschild solution, which makes use of Swartzschild coordinates and the

Swartzschild metric, good branding, leads to the derivation of the Swartzschild radius, which is the size of the event horizon of a non-rotating black hole. So not even 16, 15. Swartzschild accomplished this while serving in the German army during what? Well, he lost the war, jokes on him. He died the following year possibly from the autoimmune disease, Pemphigus,

which he developed while at the Russian. So this guy gave his life for black holes. That's actually, that's admirable. That's admirable. So we can't, we know, we believe that they exist, exist theoretically and we believe that we can prove this through the continuous work we've done since Einstein first introduced the theory of relativity. But do you see a scenario where something like a black hole actually doesn't exist? a lot of observations for things that smell, look, taste like black holes. So if they're not black holes, we have to understand what they are. People are trying to come up with alternatives, like very dense stars or dark matter stars,

stars that would explain what we see, for instance, at the center of the galaxy. But so far, there's not really any explanation for what else it could be than, in fact, a black hole. And black holes are not such controversial in themselves. We understand how they work, we understand how they work. As you get close to it, as we enter, then we understand how they work. It's really only when we get very, very close to the center,

once you're inside the black hole and you can't come out of that's where we know something breaks down and Einstein's theory of relativity doesn't work anymore but we understand using the laws that we have at the moment what would happen if you were very close to the black hole for instance and we understand what light would see. And we can start looking at what we see at the very center of our galaxy. We see that there's a big mass there which smells like a black hole, that has the mass of what a black hole will be and the radius of what a black hole will be. And we can look at the light deflected from behind that black hole and we see that this light is

Experiencing exactly what we would have expected According to those solutions and this is in the center of our galaxy You said yeah, so am I thinking this correctly this would be where the Sun is effectively And now that the Sun is at the center of our solar system Yeah, and we are our solar system is a little bit on the edge of the galaxy. Right. Okay. It's not close to the center. It's towards the edge. But if you look at the Milky Way, have you seen the Milky Way?

Yes. Yeah, so if you look towards the Milky Way, and you really, really look very closely, you're not gonna see anything. But people have done with instruments, so they've done with the Keck Observatory, which is a series of different telescopes that have been tracking stars at the very center of our galaxy.

And then they've seen that they're orbiting something at the very center of our galaxy. And so there must be a big, huge mass there, which is confined to a very small region of space. I say very small region of space is still millions of kilometers. It's not. Oh yeah. It's not small. We can't just go there.

So that in itself, if we believe in Einstein's theory of general relativity, it should be a black hole. So then in the meantime, people have looked at how light gets deflected around that black hole. And this is an observation done from the Event Horizon Telescope. And there's been a few years ago, I don't know when it was, 2020, 2019 or 2020, the announcement of black hole shadows. Black hole shadows. Black hole shadows where it's not really the shadow of a black hole shadows. Black hole shadows. Black hole shadows, where it's not really the shadow of a black hole. In fact, it's the... it's the shining of a black hole, if you will. It's really seeing light

from around the black hole that is not emitted by the black hole itself, but emitted by objects behind the black hole. And so by looking at that, people can determine whether light is following trajectories, which is what we would have expected according to those black hole solutions, or if it's completely different. And so far it's an impeccable agreement with what should happen if it was a black hole

there. But the shadows of things on the other side of the black hole, which, you know, when we think, when we watch the movies and hear about some of the physics, it's like you go into it and like you're gone and you're somewhere potentially very far away, yet there is something large enough there that could literally cast a shadow into this. So no, the shadow is just, is just a word. In fact, what happens if you, if you really enter the black hole, that's it. So what we see, those images that we see, it's light which hasn't quite fallen inside the black hole, it's just escaped it. A lot of it has fallen inside the black hole, but some of it

were just sufficiently far away that they've been affected very strongly, but haven't fallen inside the black holes. So they're just escaping, we can see it. We can see it here. Where do we think, when it comes to the black holes, like in this hypothetical one that appears to be there in the middle of our galaxy, do we think that that, do we have any evidence to paint how many galaxies

that could lead to? Is there anything even remotely that's not just crazy theoretical that could lead to is there anything even remotely? That's not just crazy theoretical that that could make an estimation on that or are we totally unsure? How many galaxies have black holes inside them? Yeah, or where like the the black hole we're looking at within our galaxy Yeah, how many galaxies that may lead to just right there from that just to go to one other place I love your question. A billion other places? You're assuming this is bridging to something else.

It's an assumption, yeah. So maybe, I think, at the moment, if you ask most people that would say zero, we don't think it leads to a white hole or bridging to a shortcut to somewhere else. Because what we know is, you fall inside the black hole, then even as you enter a black hole, like this child type of black hole, as you enter it,

even the notion of space and time get switched into one another. So just like for us, when I can't decide where I want to be in space, I can decide I want to be here, I want to be there, that's okay, I have a control over this. But I unfortunately can't decide where I want to be in time. It's just gonna push me forward. And that's just the way it is, I have to make do with that.

Now, when inside the black hole, in fact, you can't decide why you want to be inside the black hole. It'll just swoosh you to the center of the black hole, in fact, you can't decide where you want to be inside the black hole. It'll just swoosh you to the center of the black hole and you have no choice on it. So the notion of radial space and time get in fact changed when you go inside the black hole. So there's lots of things that go quite crazy

as you enter the black hole. You have very little chances of surviving it as we think of ourselves. At least I don't think I would have. But when you get very close to the center of the black hole, the only thing I can tell you is that I can no longer use Einstein's Theorem of Relativity to tell you precisely what happens there.

It breaks down. Meaning like the gravity as we know it, it's an entirely different force. Even space time may be different. And I don't even understand whether I should think of particles. I probably think I shouldn't even think of particles. I shouldn't even think of space time

in the same way I'm thinking about it right now. And so I don't even know how to ask myself the question necessarily of what happens there if I can't even tell you what there means. So then there's a lot of speculation and some people come up with possibilities where this would be the bridge to something else. But in fact, those are speculations. If you ask me, I would say we have no evidence of anything at all. All we know is that things get very complicated. But assuming that you can trust your theory and then start to bridge it to something else, would in itself require some type of energy which is unlike anything that we know of,

and it's typically very, very unstable. So if you want to have those kind of bridges, you need them to stabilize us with some kind of energy and that we don't know how to do. So it's not something that, unfortunately I can engineer for you right here. I was gonna say, like, is that even something... Is that even something we're gonna be able to measure,

like, in our lifetimes? Because we can't go... Like, I'm thinking to Douglas Murray, you've never been to a black hole? You can't talk about black holes if you've never been, but, like, we can't go, we can't check it out and see what it is. It is totally hypothetical,

and we can observe something that may look like that. So this is why it's so, so cool that there are these theories that are equivalent to other things. And so that's why it's so cool that for instance, you have black holes, which are gravitational things, and yet they're completely equivalent to a projection on a surface which has no gravity. And instead they behave more like not necessarily condense matter system, but more like other materials in extreme conditions,

but other things that we can have more control over. So that's one possibility. We can try to make traction into those dualities. Another way to make traction is to say, in fact, what happens at the very center of the black hole is very similar to what happened at the very beginning of the universe. And similarly, I can't go back in time and see what happened at the very beginning of the universe. But we can observe things from the very beginning of the universe. In fact, everything we are is the results of what happened at the very beginning of the universe. In fact, everything we are is the results of what happened

at the very beginning of the universe. And some of that has implications for not only who we are right here, right now, that's quite far-stretched, but how things are distributed, how galaxies are being distributed in the universe, what is the temperature of the sky? Do you ask yourself that question? You know, can't say I do that often. So ask yourself that question. I know it gets cold when you get up there. It's super cold, it's super cold, but there is such a thing as a temperature of the sky. We can go into that if you want. Please. So when the universe was really, really young,

it was very hot, very dense. And rather than being beautiful as it is now, it was more like a soup of fundamental particles all mixing together. And so if you imagine you are a photon and you're trying to travel, you're not going to go very far because you're going to be bumping onto lots of people, lots of electrons, for instance. But as the universe cooled down, it relaxed a little bit, it became not as hot, and the

electrons got trapped around nuclei and so those created neutral structure. And when that happened, the photons could all of a sudden, go freely. And so there is a time when you look back in time, or when you look in the sky, when you look far enough, you look far enough in the past, in fact, there is a time where there's a surface where the photon got free, just like imagine you look at a cloud. And it's all gray. But what is it when you look at the surface of a cloud, you can't see inside the cloud. Because inside the cloud, it's it's humid, which means that light can't travel

very fast. It's been scattered through the water molecules in the cloud. And then as he reached the surface of the cloud towards us, then it's free, it's free to go. So we can see all the way up to the surface of the cloud. Now we can do the same thing to the surface at the beginning of the universe to the surface where before that it wasn't a cloud per se, but it was a soup of fundamental particles. So we can look back in the sky to to many, many years ago, to a time where the

universe, I'm going to say something wrong, but I think was about 300,000 years old. You can Google the surface of last scattering and you can look at that surface and then you see how the universe looked like at the time. It's like looking at the surface of the cloud, but only what you're looking at is how the universe looked like when it was very, very young. What did you say? The surface of last scattering. So that's the last scattering.

That's the last time photons are scattered. The surface of last scattering is the point in the early universe, approximately 380,000 years after the Big Bang, when photons became free streaming, after decoupling from matter, marking the transition from an opaque to a transparent universe. The surface is the origin of the cosmic microwave background, which is what we observe today, is the faint microwave radiation permeating the universe. So looking at that, in fact,

tells us a lot about how the universe was when it was very young and almost as young as at its moment of creation, at the Big Bang. In fact, what we can see is that the surface, the temperature of the sky on that surface is exactly the same wherever we look, within one part in 100,000. So the temperature is exactly the same

with an incredible precision. And you can look in this distance, you can look in this direction, and you can look in another direction, and it's exactly the same within one part in a hundred thousand. And now if you remove this constant temperature from exactly uniform, wherever in the sky, you look at, you see those tiny, tiny fluctuations. So when you, you see that picture, if you, if you Google cosmic microwave background.

Would it be under here? Yeah, so this is the third picture. That one? Yeah, that one. So this is a picture taken by... Of the universe. That's right. These are the temperature fluctuations.

This is how the temperature of the sky is once you have removed these very, very, very uniform temperature. So that constant temperature, you remove it and you see tiny, tiny fluctuations. Based on proximity to stars and things like that. No, these are based on, in fact, from quantum fluctuations at the very beginning of the universe. So at the very beginning of the universe, just after the Big Bang, there were

fluctuations which are quantum in nature, they're just popping in and out, and satisfy some statistics which are not the same kind of the statistics we know classically, the quantum statistics, but you just have a probability for something to happen just out of the blue. Quantum mechanically you can't prevent that from happening. And they got imprinted in the sky. And that satisfies exactly the right statistics, exactly the right distribution as what we would have expected if they were quantum in nature. And quantum in nature from the very beginning of the universe. In fact, before there was such precise observation in the sky, so this is the third big mission that looked at the temperature of the sky.

This is from Planck. Before that there was WMAP, and before that there was COBE at the end of the last century, I guess. COBE made the first measurement of the temperature of the sky and those fluctuations. And before we had that, there were all the possibilities out there, like cosmic strings and other kinds of models that could potentially have explained observation.

And since the first satellite measurements of the temperature of the sky, we now know that all of those alternatives are not correct. And in fact, it seems to be pinning down to quantum fluctuations at the very beginning of the universe. How did we come up with the calculation in the first place though of 380,000 years from, say like, I guess they were referring to Big Bang to that? That's right.

How did we come up with when the photon escaped? So this is related to the temperature of the universe. We actually have a very good handle on how the universe has cooled down, how it has evolved. In fact, the biggest handle we have on the evolution of the universe is the concentration of various kind of elements

being present. So the most natural element and most abundant element in the universe, among us, the dark components are the most abundant, but among us it would be helium. And then if you took two helium atoms and you put them together, they're gonna generate, sorry, the first scratch up, the most abundant one is the hydrogen atom. You were happy with both. Yeah, we got a fire here now.

It's misinformation. It's a hydrogen atom. And then you take two hydrogen atoms, they can make helium. And that makes your voice go up. That's why. That's why. I was fighting my tongue on that joke. I held that off for like a minute.

Give me credit. And that's why you're like, oh no. So anyways, you have many different elements in the universe, but they only get produced once the right of them gets put together and That only happens if the universe evolves at a given rate And so if we know how many how much of a particular kind of element there is in universe That we have a good handle on how fast the universe has been expanding So we actually this is a really really precise. We can't play with that very much.

Now, wasn't there an argument and maybe I'm misremembering the numbers or what the what the status was here. But I think this was back in 2023. I remember, I think Brian Keating was in here talking about it. But wasn't there an argument suddenly about whether or not the universe was around 13 billion years old versus 26 billion? Maybe, I don't know. No. So, typically nowadays we say it's 13.8 billion, something like that. That's exactly correct. I had that one right again. So, I don't know, I should ask him what he had in mind. There's various stuff of arguments about all sorts of things. Now I'm trying to think what he was thinking about. Yeah. Can we Google that, Alessi? AG universe 13 billion versus 26. Just keep it round numbers. On the temperature topic. Yeah. Is the temperature of what it is now assumed to be consistent?

Yes. Yeah. Is the temperature of what it is now assumed to be consistent? Yes. Yes. So how does that work? Because if you go back to this original side, everything was dense, everything was hot because it was compact together. So if the universe is continuing to accelerate, wouldn't you assume it's going to get colder? Yes, it's going to get colder and colder. Yeah. It's going to be very cold. So yeah. All right. So we're going to get very lonely because things are going to get very very diluted as well Yeah, yeah All right. So we have this up here. Unless he got this the age of the universe is generally estimated 13.8 billion years However, recent studies suggest that the universe may be significantly older potentially around 26.7 billion years The new research while sparking scientific debate proposes that the age of the universe may be nearly double the current estimate.

So Regenra Gupta of the University of Ottawa in a study published in the Monthly Notices of the Royal Astronomical Astronomical Society suggests a much older age of 26.7 billion years. This proposal is based on observations of early mature galaxies by the James Webb Space Telescope which seems to contradict the standard age of the universe. Ah yeah, yeah. Yeah, I know what you mean. That makes sense to you. So what does make sense is indeed there's been observations of formation of galaxies much earlier than we would have anticipated. And that's great. That's great. Anything that challenges us is great.

Now, whether the explanation is that the universe is much older or anything else, I don't know. I really don't know. But it wouldn't change the math on solving for, say, the 380,000 years post-creation where the photon escapes, because that's based on the temperature changing upon creation and not necessarily when creation happens.

So whether it happened 13 billion years ago or 26 billion years ago, it's the same concept, temperature speaking at the beginning. So what that doesn't change now is in fact, the time from us to that surface. Okay. And we can look at that surface, yeah. Got it.

Now, what may have happened at the very beginning of the universe, we don't know exactly. And there can be much more time there, or far less time. At that point, we don't know. Far less time? Well, no, sorry. What I mean is, we set time Zoror as a big bang. And then we sort of set up the clock from there. But precisely what happened during the first 10 to the minus 22nd, whether that was 10 to the minus 22nd, or it was a tiny bit more, but tiny bit less,

or there was something before that, we don't know. Where do you think it all comes from? Like, do you believe in a creator? I believe in physics. So I believe that something must have happened. The curious question is, it's much more natural than nothing was there. If you ask me, what is the highest probability of the outcome? What is the outcome with the highest probability?

I would say there's nothing. So it's amazing that we have the chance to be somewhere and to ask ourselves those questions. Now, I don't need to have something with its own intelligence or its own being to explain the creation of the universe. I think science is much more creative than that, even if we don't really know what the answers are. Right. And this is kind of like where science and religion fly in the face of each other, and yet they seek to answer the same question. Like where it all comes from, which is so fascinating to me that we've created like an enemy system there throughout humankind, where it's like, oh, one is different than the other, they're supposed to fight each other, but we're trying to get to the same level. Yeah. And this is something that you

can, you recover in all civilizations. You recover in everybody. We ask ourselves the same questions and we actually very curious to understand where are we coming from and how it works and what does it mean and where am I going from there? Yeah, I don't know. That's like one of those that keeps me up at night is obviously as a complete non physicist, but thinking about like how this could happen. You know, if you look at if you look directly at like Lawrence Krauss's theory where it's like, well, it just came from nothing. Like there was there was nothing that existed. And then something happened and existed. It's like, okay, but we can't even picture what nothing looks like. That's why you know what I mean? Because like, if you think of nothing, you think of an empty room, which is something. That's right. That's

right. That's right. When you want to when you want to think of nothing, you don't even have a notion of space. And then you don't even have a notion of time, right? So you can't even say and then something happened because in saying and then it means that you switch on your clock. Yes. And you began with something. That's right. That's right. That's right. Space is something though. Space is something. Space is something. Yeah. Yeah. Dust is something. Anything is something. There's nothing. There's technically

nothing that's nothing. Unless it's in that's what even the idea I mean if you want to get real meta even the idea of nothing is nothing something It's yes crazy to me, but you know I just don't know I Think I think religions make a lot of assumptions on things and so I don't personally ascribe to anything But I'm open-minded on you know Whether or not there's things have been passed down that we could be rooted in some truth or found out from something beyond our current understanding But it's like I don't know how something this perfect not just our earth

Not just our little solar system here and our galaxy But everything that could be beyond that to comprise the universe that is so mathematically and probably lined up to just the right tick that it works and things can exist. I don't know how that science couldn't come from some form of a creator. Now whether or not that's like God, as people look at it in religions, or like just some other being. Maybe it's like the movie Men in Black, the ending,

where suddenly, like, it's just the marble ball in the middle of all of it, and there's just a guy playing with it. I don't know. But to me, I still can't conceive of a scenario where there's not, like, some puppet master over the top that made it work. We don't like we don't like being just a random anomaly. It doesn't right. It doesn't work

in my head. Yeah, we don't like it. It it bruises our ego. Maybe that's what it is. We don't know. We don't know. Does that ever affect like how you look at your life itself? Because you seem so happy-go-lucky, and you love learning, you love working on your research, like you have such a good attitude about things. But if it did, if your research pointed to

there really was no purpose, we're just a mathematical anomaly, would that change your outlook? So I certainly don't think there's any purpose. There's no purpose of us being there. But that's why our purpose is for us to understand why we're there. I don't think we've been created

because we have a purpose in itself. I do think we're just a random anomaly. We know us as individual, we're just an accident. And if you hadn't been you, you would have been someone a little bit different than you. And it's not like anyone decided to create you exactly the way you are. Of course you are perfect.

That's great. Thank you. But no one came down and designed you in the outset. You would have been slightly different. Yeah, they messed up some things in the design. I got some complaints to put in. Okay, next time, I'll try. I'll try better.

So we are all accidents in one way or another. Maybe I misunderstood the very beginning of that, though, but you're saying we don't have a purpose here, but like, I forget how you put it, but I'm trying to find our purpose. So how does that even work? No, I don't think I've been, I, as a the Earth or the galaxy or the universe has been created with a purpose. But that's why us as human we like to give ourselves purpose and my purpose, my self inflicted purpose is to try to understand where we come from try to make sense of all of this. But I don't think anyone set us up because we had a particular purpose. I do personally think we are all accidents in one

way or another, but they are happy accidents. And so that's a good thing. But the fact that we are an accident doesn't explain it. There's still something to understand. It still did happen. There's a lot of other things that could have happened, and they haven't. And there's a lot of other things I can imagine that can, in fact, never happen. So the fact that... Like what?

Well, there's all the structures of reality where I know that they don't work. I can come up with theories, they simply wouldn't work. The things are in a particular way and I could have imagined that they are, would have been in a very different way and that wouldn't have worked. Why do we experience life though

with its highs and lows though? If they, I mean, this is getting really meta and it's kind of impossible answer, but I do enjoy like having these philosophical conversations. Like we live on an earth really meta, it's kind of impossible answer. But I do enjoy like having these philosophical conversations like we live on Earth. You said it's a happy accident. And if that's the case, like I would agree it is a happy accident. But we live on we live in a world where there is good and evil.

Not everything's all happy, right? Like every day there's it's it's on different scales somewhere in the world right now someone was sold into slavery. That's way worse than me stubbing my toe, right? But it's all on the same level of like those are net negative things. One is just way more negative. But like we live in this constant yin and yang of like in order to see the light we have to know the dark. So how does something like that exist if it's just, how does something like that not have a purpose if it's just sent here to exist as if it's I don't know a video game. Well you even thinking it's a video

game I don't even think it has as much of a purpose as a video game it just it just happened and I want to think of it as a happy accident, because we are here, but of course, there are things that are not happy accidents. And there's a lot of other planets that could have got formed and haven't. And therefore, there's no life on them. They were just not quite right. There's all of those other planets where it's just not quite right for life to happen in there. And then there's a lot of things that simply did not happen. There's a lot of you that simply did not come into existence. And that's sad for all of the other yous that haven't come in there.

But it doesn't mean that you were created just the way you are because there was a purpose. And maybe there were, but I don't think so myself. Yeah, you don't have science to prove that right now. That's right. I don't have science to prove that. But still, in analogy of how you got created, there's still science to understand what is the mechanism that enable a human being to be

created, and what is the mechanism that enable a planet to get formed? And that is a meaningful question. And why are planets in the way they are? Why they are the shapes they are? Why they are the size they are? Why they are within the distribution they are? All of those questions we can ask ourselves.

Why we, the Earth, got created with just the right condition for us to be able to ask ourselves that question This is this becomes more of a philosophical question because sure if it hadn't been just right We wouldn't have asked ourselves that question and if all the planets would have been slightly different But life was still possible in them. We would have thought that's the only possibility, but but maybe it's not maybe we're just asking ourselves I would have thought that's the only possibility, but maybe it's not. Maybe we're just asking ourselves questions based on what we are experiencing,

and that's not all the possibilities. Did you grow up around religion at all, or was it in your family in any way? Not particularly, no. But I grew up among quite different way of thinking, and people thinking our place on earth as human was quite different. And different cultures think differently in fact in what our purpose is and how we in fact should help each other and what the role of the societies are. Some of them are much more rooted around a core and some of them are much more individual. And I think that is also affecting how we think of ourselves as a purpose.

Is it the purpose of us as individuals? Is it as a family? Is it as a society? Is it as a whole civilization on Earth that has many different meanings? I agree. I think that's a great point. Like if you look at some of these, this is an extreme example. But if you look at some people these, this is an extreme example,

but if you look at some people on the earth who still live off the map, you know, think of like the uncontacted tribes or something like that, they at a root level, you know, in their communities of 150 to 200 people, sometimes things like that just random round numbers, it's like they rely on each other for survival every day and for being able to put food on the table. And I mean that at the base level, living off the map, away from resources, not knowing the things that we have access to. And so their understanding of like

what the meaning of life is and everything is entirely different from us who are sitting here with our iPhones. It's a crazy thing to think of that. So you grew up in Switzerland, right? Partly. Partly. So some years, yeah. Yeah, do you want to go into the origin of my life?

Yes, please. I think it ties together. I was born in Switzerland, yeah. I grew up in Switzerland, then we moved to Peru, to Ayacucho. To Peru? To Peru. Wow. Ayacucho, do you know Ayacucho to Peru to Peru Ayacucho to you know, I could show you know, okay It's in the Andes. It's quite high Oh, I've seen it my buddy Paul Rosalie's out in Peru by the Brazilian border in the middle of the Amazon

So when I went in to see him, I was flying over the Andes which are incredible. Yeah Yeah It's beautiful. Beautiful Quite Quite different. Then I lived in Lima. I spent some time in Iquitos, which is by the Amazon. Was it there? Well, he was well where he is, it's I don't even know if there's a town where it is because he's actually out deep in the jungle. Like he's in a research station in the jungle. What was the name of the town on the edge of the jungle that we started at? I haven't thought about

it in a while. So maybe Iketos. That's typically the biggest place. It's not that it's like it's on it. He's on the Madre de Dios River. And there's a town right there. That's gonna kill me. I forget it's like a site. I think it's like a saint name, something like that. But either way, so you grew up, what was the name of this again? The eqitas, eqitas. Okay. And then I spent some years in Switzerland. And then some years in Madagascar. That's where I was till I was 18. Wow. And then- What's going on in Madagascar? Well, nowadays, a lot, I guess.

At the time, at the time, Madagascar is an amazing place. It has its own- It's beautiful. Ecosystem. Yeah. Because it's separated out, in fact, all of the flora, all of the animal life has evolved in very different ways than it has in the rest of the flora, all of the animal life has evolved in very different ways

than it has in the rest of the world. And even the people there, the culture is very, very different from anywhere else in the world. So go and visit if you can. Yeah, I would love to. Pretty amazing things. And the nature has so many different levels of diversity

between places which are more like the jungle to places that are much more like deserts, to places that are near the sea. It's a beautiful place. Why were you going to all these different places? What did your parents do? Why not? Why not? What were your parents doing?

Because you were just a kid. They were working for support for sustainable development What did your parents do? Why not? Why not? Well, what were your parents doing? Because you were just a kid. They were working for support for sustainable development in the global south. Very cool. Yeah. So it depended precisely what it was, depended on the different countries. In my guess, there was a lot about deforestation and trying to work with farmers in getting more sustainable ways to grow rice for the rice culture in a way that has an impinge

on deforestation. Depending on different countries, also a lot of work related to younger kids' education and working in a way that is sustainable for the younger kids to go to school. Because the way things were set up in some of the more remote regions was, in fact, quite different. And everybody has to work. Everybody has to work as part of the village work. But that also means that education for younger kids

is sometimes not as easy to access to as we used to. Yeah, like when you go to a, you were a teenager in Madagascar? When you go to like a remote place like that and your parents are working within the actual people who live there and everything, like and everything, what's school like? I'm just thinking about growing up in Switzerland and then going to Peru and then going to Madagascar.

These are very different places. Like how do you, were you just constantly independent, homeschooled or were you going to international schools in those areas? So I depended on the different places. In Peru for most of the time I was in the local school. In Madagascar, there was a French school in Antananarivo in the capital.

So when we were in the capital, we would go in the French school when we were there. I never was home school, but some of my friends, that's what they did. It depended a little bit on the situation. In fact, it's, you know, we used a particular way of living, but it's not so hard to adapt to quite different ways

and things you get by very easily. One way or another. Why physics then? Because based on like how you move around, you think you'd be in the biology or something. No, that's true. But I think that's true. I think I would have liked biology. It was just too complicated for me. Biology was too complicated for physics. It's so complicated. There's so many different things. Whereas physics, you really go down to the root of everything. And I think really why physics was that thing that remained completely consistent.

Wherever you went, it made sense. And the sky was there, the moon was there, and the laws of physics were the same. You can really rely on it. And I think that's why I was really eager to being able to hang on onto something that didn't make sense and was the same wherever I would be. So more uniform because this on your moving, it'll pause everywhere. That's right, that's right. So by the time you were applying to university

as a teenager, you knew you wanted to go towards physics. Yeah, yeah, yeah, yeah. And you still love it all these years later. That's pretty cool. Yeah, yeah, yeah. I love it, I love it, yeah, yeah, yeah. I love it, I love it. Yeah, yeah, yeah. Everything has its ups and downs, but no, we are so lucky to being able to be there

and just ask ourselves questions. What happens if this is like that? And then we can go and talk with people that actually build experiments and look for things. It's amazing. Yes. It's really incredible. The level of creativity that we as human have come up with

in trying to understand what are the possibilities and whether they're actually connected to reality and realizing, yes, they are. These crazy ideas, can you imagine? These crazy ideas of quantum mechanics and general relativity and evolution, all of those things that you think these are crazy ideas But people came up with just share creativity with those ideas and then they contested it. It's it's incredible

Expand upon it expand upon. That's right. That's right. Push them further Yeah we were talking a little bit ago and and outline the whole like 1915 theory of relativity a ago and outlined the whole like 1915 theory of relativity, of general relativity that Einstein came up with and now how that's like translated towards the work you guys are doing today. And before that, we were talking about like string theory and where that can tie in and everything. But like, where do we, maybe this is like way too simple of a way to ask it, but like,

where do we stand based on Einstein's original interpretations, which is some of a lot of which has been disproven? What is the current accepted theory, if you will? Yeah. In fact, Einstein's theory is still, I would say, the best game in town. We do spend a lot of our time emphasizing what doesn't work, because that's what we paid for. Because if everything just worked beautifully, that's it, we wouldn't need to do anything, everything would be solved. But we often don't

emphasize enough how much things are really, really working incredibly well with Einstein's Theoretical Nativity. And so it's, you really have to dive into the center of a black hole, the beginning of the universe, a really crazy environment that we don't see every day to start seeing signs for the need of going beyond Einstein theory of general relativity. Other than that, it's working really, really well. It's a best-tested theory.

It works over 18 orders of magnitude. 18 orders It works over 18 orders of magnitude. 18 orders of magnitude. 18 orders of magnitude. So I can test gravity on things which are as close as two very thin sheet of paper within a micro meter distance apart. So 10 to the minus six meters apart from one another, so very very close to one another, and that works exactly as we would have expected. And then we can test gravity over

distances which are millions of light years apart, and it works also exactly as we have anticipated. And we can predict that, as I was mentioning, that black holes exist and not only they exist but when they merge within one another they distort space-time in just a way so that there are gravitational waves with a very specific spectrum that propagates through the universe and we can predict the effect of those gravitational waves when they reach us on Earth some millions of years later and that is all completely consistent. We measure that exactly in the way we would have anticipated according to Einstein's theorem of relativity. So all of this can't just be an accident. We can't just say, oh it's wrong and we have all of these successes that we can explain in

different ways. Because you'd be throwing the baby out with the bath water. We would. There's so many things which are really, really right. There's just aspects of it that they're like, okay, well, that wasn't right, but the pathway, as we pointed to earlier, that he created is there. It's absolutely right. There's really some element of, I don't know how to define truth, but there's something as close to some element of truth

in that that I can't define. There's really something which is really correct in our sense of the original activity, and whatever, however we want to go beyond it, we always need to make sure we understand how to recover it in all of the observations that we have, in all of the experiments that we have, because we made, not me, but we as a human being, we made some predictions, and they turned out to be right. So things are really correct.

So this is the first thing. It's really even much better tested than anything else. We think we see the universe. We think you look at night and you see the stars, and you see the light coming from those stars and this is how we see the universe. And we think we've done that for thousands of years. We've done that as human since the beginning of civilization

and that's how we actually understand our environment, that's how we understand what goes around us by seeing things through light. But in fact we understand gravity better than we understand light. We understand how gravity, gravitational waves propagate and how it behaves on all sorts of distances better than we can understand just the light in this room. That's almost surprising to hear though, because like, you know, light is something we can see. I guess gravity, it's like because we can feel it, but we don't. Yeah. It's just there's a mathematical equation that forces us to the ground. Yeah.

But we don't know necessarily where that all the way at the end could emanate from because that gets to like we were talking about earlier like the purpose of it all. Yeah. It seems surprising right and particularly since we have so much experience interacting with light and we can see it we can understand it we can feel it. We know the can feel it. We know the speed of it, and now we know the speed of gravity as well. And we know that it's exactly the same as that of light. The thing is with gravity is that it affects everything. And so even though we think that we as individuals, we don't interact too much with gravity other than

being pulled towards the Earth, we know the effect of gravity on everything else, and nothing can be shielded from gravity ever. And so because it has an effect, not a big effect, in fact, it has a small effect, but on everything, that means that we can actually have a very good understanding of what it is, or how it should behave, and whether or not it's in agreement with the series that we have at our disposal at the moment. And it is, very much is. One of the things Gio and I were talking about right before we got on camera was the concept of like gravity. How'd you say Gio, gravity pulling us down or pulling us in and then dark energy was on the

Antigravity topic trying to put two and two together. So I mean, you're gonna explain it We were talking about dark energy and dark energy effectively being an aspect of Antigravity, so if gravity is going one way, anti-gravity is pulling you the opposite way. Yes. So for us, for me, we still have a very, let me say Newtonian perspective of what gravity is, because that's the way we experience it on earth. And so we really always want to come back in our mind to something like there's a mass here that attracts us because of gravity and so if things are going the opposite direction we like to call it anti-gravity. So that's why that's how this picture comes about because in our mind it's hard to have something else different than that but in fact according to Einstein's theory of relativity, gravity is so much more than just this phenomenon

as us being attracted to the earth. That's just one realization of it. And in that case, it seems like it's an attractive thing. And two masses always get closer together. They would attract each other. But that's just one realization of it. Anything is, has an effect to gravity, because anything leaves on the

spacetime. Spacetime is everything. We live in the spacetime. So no matter what you are, you will have an effect on spacetime. And anyone else traveling by will see your effect because they will be traveling on that spacetime. And therefore they will see that you have distorted spacetime. So is that what you're saying? Just having thinking of nothingness is something? Yeah. This is almost like that. Just you, by thinking, you affect space time. And so can you imagine

that you are bending, you're thinking so hard, you're bending space time, right? Yeah, the overthinkers out there, we're- It's giving you too much power. Yeah, we are bending everything. You are, and I can feel it. And I'm. Can you imagine? No.

No. You have to be quite sensitive to feel it. But that means that the way gravity works is actually very subtle. We are thinking ahead about gravity being this attraction, and if we see things not following that pattern, then we'll like to associate it with something which is anti-gravity. But it doesn't need, it's not really anti-gravity. There's nothing, it's not going against gravity. It's playing with gravity. It's

almost when you know, there's this gravitational acceleration that we do. NASA does do use that to use the gravitational fields of planets to accelerate probes to push them in the edges of the solar system. So you're actually using gravity to do something which would have seemed counter-intuitive. We do that technologically, we do that for space exploration, and dark energy does that. It uses how gravity works, it just follows the rules of gravity. It's not doing anything special, It's not doing anything special. It's not doing anything crazy.

It has some positive energy. So it's not doing anything anti. It's not switching gravity off or anything like that or switching gravity the other way around. It's just playing with gravity in a way which is very counterintuitive to us and which has a house where effect to make space being not only stretched, but stretched at an accelerated rate, but just playing fair with gravity.

There are rumors that certain organizations that won't be named DARPA have potentially come up with... I don't know, some anti-gravity science. Bring it on! Do you believe that that is... within the realm of human possibility to create? So, you have to tell me what you mean by anti-gravity.

They make, allegedly, they have access to systems and this is where people start to bring in like the alien argument and stuff like that, like have they recovered stuff that's not this planet that had this type of technology, but they have access to systems that do not have, I'm gonna explain this wrong, but they don't have any jet propulsion that we would normally need to navigate outside of our gravitational area. And they just float silently in... within our sky. Like, do you think something like that can exist?

Yes, so I'm sure it exists and... The only thing they've done out of it is create rembers. They haven't used it for changing the world. Allegedly. Yeah. Allegedly. Yeah. Bring it on.

I mean, DARPA says they were talking to dolphins telepathically in 1992. Yes, yes. So there's a lot out there that maybe it's a little different than I thought. I'll admit when I see a dolphin now, I think twice. Yeah. But it's like- So does that rely on dolphin? Do you need to talk to dolphin to go through antiquity?

I mean, I heard dolphins are smart as shit, you know? Like, it could be interesting. Maybe they find a way. Yes. But it is, to your point, like, point taken in the sense that we are talking about hypotheticals that we have not been shown the proof of. And it could just be rumors or whatever. But we could also exist in a

world where there are you know scientifically brilliant people who are operating on clandestine completely secret programs and have a complete have a completely different understanding of the nature of our reality than we do and because they don't tell us it it's like their little secret. Like I do think that's possible. I'm not saying that's the case, but like, could you see how that's possible? So what I can tell you, let me not go through that,

but what I can tell you is that we know there's dark matter. There's dark matter out there. There's a completely different sector of matter and there can be some in this room. We would feel it gravitation. It's here with us? It could be, so we don't know exactly what the size of dark matter is. So it could be something quite big

where it wouldn't be quite in here, or it can be something quite small. It could just be particles and it could be some little clouds of dark matter in here. And there could be some, if you wanted to think about that, there could be some civilizations of dark matter that are living right here among us and doing all those things. We wouldn't see them,

we wouldn't smell them. All we would do is feel them gravitationally. And we do feel them gravitationally in the galaxy. We do feel the gravity of the dark sector. We do feel the gravity of dark matter. You described it as it could be a civilization though. Well, I'm just provoking you a little bit, because why not?

Because I don't want to confine myself in saying, do you have life, do you have structure? It needs to be some same kind of matter as what we are made out of. If you ask me, honestly, I think dark matter is a little bit too diluted. It's a little bit too puffy and diluted to have had the chance to coordinate each other and end up being a civilization. But maybe I'm too narrow-minded and maybe it's possible

that they find a way. You could have the dark matter is not just one kind of particle, they could have different type of particles that interact with each other. What we know is they can't interact with each other too much. But so what maybe they can still interact with each other and do it in such a way that there's some sort of organization within this dark matter. I don't believe that. But that's a possibility. Why not? Why not? You can't, you can't prove me wrong. So far, it could it could happen. Yet they live in that space time. They are here. They when we feel them gravitationally. So you can think of

all of those things. In fact, science thinks of all of those things. And we have proved that there's all of those things that are incredible that are living just here, maybe not in this room, but definitely in this galaxy. They are here. There's something else that we can feel gravitationally and that we know we can't access directly through the standard channels of communications. So I don't need to go through all of this anti-gravity because the way gravity works is already so much more powerful and so much more creative and could give us access to so much more. And that I know that we have strong evidence that it is actually existing. Now you basically, the concept of massive gravity is what you wrote about and kind of like birthed the new movement of.

And that was what like 2018 you put out a paper on that is that right no that was way yeah yeah yeah oh no you want an award in 2018 maybe that's it okay so when did you start working on this so it's always like that there was never a point when I thought okay I woke up in morning morning and say, I'm gonna be controversial today. (*ALL LAUGHING*) Or maybe every day I say that. (*ALL LAUGHING*)

And let me just come up with something out of the blue, just because. So, we always explore things, and we always try things. When I started doing the research that I do, I was looking into extra-dimensional space, because why not? There's the three-dimensional space that we know of in here, but why three? Why? I think that's one of the most fundamental questions we can ask ourselves beyond where do we come from. I think along with that is why is it that we ended up in a world, in a universe,

where we can see three dimensions of space and no more? And so if you want to ask yourself that question, you need to ask yourself what would have happened if there were more dimensions of space? What would be the consequences? And some of the work that I was doing is trying to understand if we can explain the evolution of the universe as being the motion of our surface, our universe would be embedded on a surface in an extra dimension.

And so the evolution of the universe, even how we see things happening at late time, that would just be a consequence of how this surface will be moving in an extra dimension. So I mean, really, we're thinking of crazy things. We don't. But that's where it all starts. It has to start like that. You have to think crazy. Yeah, that's right. And so nowadays, we actually have much better constraints on whether or not this is not possible, whether or not this is possible, because we have proved particle collisions at very high energy. And so if those extra dimensions were there, they have to be really small. Otherwise, when you collide particles at very high energy with one another, they would have the opportunity to start communicating with gravity,

through gravity with extra dimensions and that we haven't observed. We communicate through gravity with extra dimensions. Yeah. Are we talking like, maybe I'm taking a huge leap here, but we're talking like multiverse type stuff? So the multiverse is slightly different, but maybe in your mind, it looks like the same, but in fact, that's slightly different

because if you have extra dimension, our universe will be all of it, and you will have this extra dimension out there as well. It's just what we are made out of, all of the matter we are made out of, and the standard forces that we are governed with, aside from gravity, will be confined on a surface. So just imagine, what we know of,

where we live is the surface of this table, but there can be extra dimensions out there. But because gravity is in fact related to space-time altogether, then gravity is also in the extra dimensions. So through gravity, you can start probing the extra dimensions. So just imagine you have those animals that are living on the surface of water. That's what is it called? Like the things that like yes, like that's right. That's right So for them all there is is the surface of the water and they can't they can't go below

They can't go below. So maybe sometimes they they see bubbles coming out And they see different things but all they experience is the surface of the water. Now, actually, there's a whole world out there, which is the depths of the pond and fishes living in there and plants, which sometimes there's bubbles coming out of and all sorts of things. And so to really understand what the experience on the surface of the bubble at some point, if they were clever enough, they will need to start accounting for the fact that there's the whole depth of the water out there. So you can ask ourselves the same question, is it what we are? Is it is our we are actually are we confined on the surface of something? And so far, it's been good enough to explain everything we observe, but there may come a point where in fact We're gonna start seeing things coming from the depth of those extra dimensions

What do you think that could look like though? Like it's I can't conceive of oh, yeah So what it could look like is you take? You take two particles and you collide them together and then they start deciding that they're gonna start sending energy into the extra dimension. Instead of staying into our surface. And so what it will look like is you send those two particles collide those two particles. And you see no outcome. What happened? I don't know. We can't see the outcome because the outcome has leaked into an extra dimension So that's what it would that's what it would look like

Well, for instance, you'll see some missing energy in some of the processes because we have no no longer access to that energy All right, maybe I'm getting way too literal with this, but I'm picturing two particles that I could actually see Okay. Now usually particles like yeah, you know, yeah. Yeah. Yeah, but I'm picturing two particles that I could actually see. Okay, now usually particles like, you know, you can't really see. But if the energy went into another dimension, I would think like, all right, the scenario where the two particles come together and collide and then go straight down, well, that is an action. The energy made them stop and go straight down together. If they collide and they go apart like this, that is also an action still within this dimension

because they go apart. If they collide and one explodes, and the other explodes, and the other has some bits still in place, that's also an action. But if they go together and then suddenly they both disappear, that's where I would say they would literally be like an invisibility type thing. I'd be like, all right, that's where it goes to another dimension. Is that what you're talking about? Yeah. Yeah

Yeah, you got it right. So those particles themselves, we don't think they would themselves go into the extra dimension, but they will Change themselves into something else into gravitational is into gravitons Maybe and those gravitons, they are able to travel into the extra dimension. Now, now what was the most controversial part when you initially started to come out with this theory? Like what was the biggest pushback in the scientific community to you? Yes. So when we, when we work on things, people derive boundaries. People set the rules of the game.

And then sometimes you... You're good. I'm good, yeah. Often when you work on those things, you don't re-divide everything from scratch because it took some people 10, 20, 50 years to derive some results. So sometimes you look at those and you say, okay, that seems right. I understand what the logic is. Let me move with that. And so sometimes it happens that when you want to make progress,

you need to take some things, some results that have been derived by the community as accepted to make progress. And of course, you never completely just take everything at face value, you try to probe it, but if it smells right, if it feels right, if you can get an intuition from that, then and you can reproduce the same results, then you may be happy with that and you might as well just invest your time making progress from that starting point, as opposed to rediscovering the wheel every single day of your life. So when I started, there was this boundary, there was this set zero that had been formulated, if you want,

by very, very clever people that said that what we were trying to do, and it's not like I was trying to do that necessarily, but what we were trying to do was impossible, because it would always lead to what we call an instability. We call it a ghost. A ghost is something that doesn't exist. It doesn't exist because if it were there, it would drive us completely crazy. If it was there, the whole structure of reality would be unstable. Yes. So it's something with negative energy. And if you have, if you have something like with positive energy and something with negative energy, they can just annihilate each other. So that's one thing. But

also, if I if I have the possibility of having negative energy, then I can prevent myself from producing more and more things with positive energy and compensate that with things with negative energy. And so if it was possible to have a pool there of particles with negative energy, then in fact, we would just be populating ourselves with particles with positive energy and compensating that with the ghosts. So that's a long story to say that when we started working on what we did, we saw that it would be impossible

to think of a theory of massive gravity. We can go through what that means. But because if the graviton had a mass, if gravity was massive, then there would always be these pathologies, there would always be those ghosts that would be there. And these were theorem, if you were, there were things that were claimed to be correct, proven mathematically in many different languages by many different people. And those have been proven in different variation of a period of 80 years.

And so when we started doing what we did, it wasn't at all in my mind to think, okay, let me try to be controversial here and say that everything people have done is wrong and just come up with my own thing. Rather, we were trying to see if we could use extra dimensions to come up with an alternative

that would help us make progress without being penalized by all of the results that people had derived in the past. Using extra dimensions. Using extra dimensions. That's right. Okay. That's right.

And so the surprise, the big surprise is then we ended up having something which worked a little bit. It wasn't perfect. So it wasn't the final story, but it worked sufficiently that it didn't make sense as compared to what everybody else had proven. It wasn't fitting in. We should have seen the pathologies in that example already, and we weren't seeing them. And that I thought it was, I was just being stupid. I just couldn't see where it was coming from. But but we couldn't we simply couldn't see it. And we kept and I kept actually for for months and months and months, calculations after

calculations, because now it becomes, in fact, technical. And yes, and you go and you actually go through pen and paper, and write as of equations, try to understand where is this thing, why I should have this negative energy but I don't see it, why that's not the case. Until we realized that in fact, all of those theorems that had been derived, they weren't as right as they thought. They had made assumptions to start with

and if you relax some of those assumptions, there was a way to make things work in actually not a very difficult way. That's gotta be kinda scary though, when you're getting to, I don't wanna use too strong a word here, but something that's maybe like even considered dogma of what you do, like this is what it is,

and then you're like, wait a minute, we've been saying this for x number of years x number of decades. And actually that, that units turn just a little bit to the left, and it should be to the right. That's so strange. I mean, even myself, I remember I gave talks myself saying, this is not possible. We have all of this. Yeah, all of these well founded results, where we know that's not possible. We have all of this, yeah, all of these well-founded results where we know that's not possible. So let's move on and let's go consider this possibility.

And even myself, I thought, well, I've been so foolish because in fact, you can just do that. Why can't you do that? And then it worked. So it's funny because you never feel very clever. You never feel like, ah, wow, I really discovered something. You're like, what did I do wrong? Yeah something. You're like, what did I do wrong? Yeah, well, you say, what did I do wrong?

And then you say, but why haven't I thought of that before? It's so obvious. Once things start to work out, it seems like it's so obvious, you think. Does that get scary though, that then it's like, well, this must be wrong if it's that obvious? Yes, absolutely. Yeah. Yeah. It's like... It's surely everybody knows about that.

And I'm not seeing the bigger picture, because you must be wrong. Otherwise, everybody would have seen it. And when we realized that, we finally understood how it worked out. I thought, okay, there's no point pushing it further because it's obvious. Everybody's going to say it's obvious and there's no point talking about it. It's often like that. Once you finally understand something so well, you don't think, oh wow, I really made progress.

It almost becomes so second nature, so trivial that you don't even think it's relevant anymore. You take it for granted now. Even though you're going to have to convince an entire community that what they were doing before was wrong. Well, I never quite anticipated it would be quite such a. No, but because because I thought for quite a long time, I thought surely they had something else in mind that I'm not seeing. Surely it must have been deeper,

but they weren't saying it. Where is this all going? Yeah, it took a lot of understanding, going back to what is it you think the real problem is? And if this is really what you think the problem is, then in fact, I can tell you there's a way to make it work. When you start working on something like this though and months turn into years and you know, you're coming across some of these things along the way where you start to realize something

could be wrong and then one thing is wrong and then it gets to the next thing and you're like, well, that must be wrong too. Do you ever worry about the, I guess like the investment of time and effort and initial findings potentially guiding you in a direction of, what's the term? Why can't I think of it right now? Like confirmation bias? Oh yeah, no, there's a lot of that.

There's a lot of that. And I think that's why it is, you have to constantly confront yourself with the rest of the community and have sanity checks, sanity checks, sanity checks with yourself and with the math. No, no, there is a lot of that. And you can, I mean, I thought you were even going to go in the opposite direction where you spend so much time going through things. And then at the end, it's possible that nothing went wrong

necessarily, but that's it. That's it. And yes, that's part that I want to say it's part of the game. It's not fun, but that's part of what you sign up for. And you have to accept that. And you have to accept that this is most likely gonna be the outcome when you start out.

It's not like every single idea I had to my head, it got realized into something. Right. Yeah, most of the time. And you don't hear a lot of those stories too. No, you don't. Yeah. I mentioned Brian Keating earlier, and one of the reasons I have a lot of respect for him is because he spent these years, you know, in Antarctica and South America, wherever

the hell it was, like observing in the universe to try to, simplifying this, but it was to prove that the universe is inflationary, which according to him would then, based on what they could find there, could confirm that like a multiverse exists, which is a crazy thing to think about. You're winning the Nobel Prize

before they even like vote on it that year, if you get that. And they did this for so many years, And then one day they realized that, that the the objects that they were observing were actually universal dust. Yeah. And it wasn't what they thought. And instead of like trying to be like, well, no, there must be no small, they're like, fuck. Yeah, yeah, yeah. Yeah. And so, so this is often used as an example as they said, they observed something and in reality, they observed nothing. And that's actually not right. They did observe, they did observe with incredible precision, but dust. And that's, it's just amazing they were able to observe the effect of dust on, and it's actually this cosmic microwave background on the same thing we were talking about. It's

incredible. So what they observed was something really physical, really correct is just not directly linked to what they wanted to observe. Yeah, and so a lot of the time, it's not like you did anything wrong. It's not it's not their fault that dust along the way is just nature is not wrong. It's not their fault that it was best along the way. It's just nature is not simple. It's very difficult. And sometimes the way you think about things, that's not the way things are going to end up being. But you should still explore them. But the concept of massive gravity itself before you got to working on it and building

upon it, the actual base had existed before, right? So people had explored whether that would be a possibility, and it's a very natural one. Who had explored that? So Einstein came up with Einstein theory, didn't call it like that, but with the theory of general relativity in 1915. And quantum mechanics started in 1925. Very quickly after that, there was going on to quantum field theory. So understanding even the fundamental forces of nature has been represented by at the quantum level. And so already in 1939, Fertz and Pauli

contemplated the possibility that you could have some quantum fields. Some of those quantum fields have specific properties that look like a graviton as in Einstein's theory of relativity, but you can also consider them to have a mass. And there's what is called the Fiat-Spowell mass term, which is considering a graviton and looking at the effect of that particle having a mass, just like we have a mass, some of the fundamental particles have a mass, some of the other fundamental particles, like the photon, doesn't have a mass.

But you can ask yourself, is it true that the graviton is massless, as in Einstein's theory of general relativity? Or could it, in principle, have a mass? The same thing has been explored for the photon. And so if that particle is massless, it leads to the photon as we know it. But there's cousins to the photon that have a mass. And those are other particles, which we call the W and the zebras on. And they are responsible for another kind of force, which we call the weak force, which you probably haven't heard of, because it's weak. Physics is simple. And the reason the weak force is weak is because the particle that is responsible for it has a mass. And so that's not quite correct. But if you want to think of it

in a cartoon picture, if you imagine you have a mass, it's quite hard to shake you around and make you want to go far and have a bigger life and dynamics of your own. So the particles that carry the weak force, they are massive particles. And so they, in fact, are responsible for the weakening of that force. So that's why we're not very sensitive to the weak force. It has a finite range, very, very small range. It's only on subatomic scale that it has a finite range, very, very small range, it's only on subatomic scale that it has an effect. And beyond that, it's really hard to get those particles too excited.

They don't want to get excited. They like to stay there and they're like bubbly things just there. And like the photon who wants to move. That's right. That's right. So now you want to ask yourself the same question for gravity. And you can ask yourself different question, you can ask yourself the question, what if there's the graviton there, which is massless. And in addition, there's another particle that looks like the graviton that has a mass, or you can ask yourself what if the graviton itself had a mass, those two questions are very

similar to one another. It just requires asking yourself, what would happen if I had a particle, which has the same characteristics as a graviton is some specific characteristics, but then you want to think of it as having a mass. And in the sense of that is not that it's massive, it's big or anything like that is just that you doesn't want to be shaped around too much, just like for the other particles. So, so it doesn't want to just zoom off at the speed of light, he wants to stay a little bit more put. But what

you mean by stay a little bit more put doesn't need to be small distance like it would be the case for the other particles, it can still be very, very large distances. It can be as large as the observable universe today. So still very very large distances but this big can become a point where the graviton is not going to want to move too far away. And it's not quite like that but it's not going to go too too fast. And so you built on top of this. And so you built on top of this. Yeah, so they started already, the first models were already from in 1939 by Fiat St. Pauli, but already there,

they started seeing that there was loads of complications associated with that. And if you weren't quite doing the right thing, you would get some ghost. And so they stopped there. And what people realize in the seventies is that however you try to make it work and make it an interesting theory of gravity,

not just a particle in its own right, minding its own business and not doing anything, but in fact, being a candidate for gravity, then you would, what this thought was, inexorably be led to having those pathologies. And so that was in the 1970s, and they were formulating it in a particular language. And then in the meantime, from the 70s to the early 2000, the way we phrase things, as in the physical community, and the way we understood things from particle physics changed a little bit. And so the way

people were phrasing that problem became refined and and people come came up with different ways to seeing that problem in in from different manners. At the same time in 1998, there was the was the first time where different groups observing supernovae converged to a consistent story saying that as you look at supernovae further and further away, so these are explosions of stars further and further away, they all seem to converge to the fact that the universe is going faster and faster. So not only the universe is expanding, but the universe expansion is accelerating.

And so there was sort of two things, several things first happening at the beginning of 2000. There was all of this thing saying that massive gravity could not work. But at the same time, we had all of those cosmological evidence showing that the universe expansion was accelerating. And so a natural question was to ask ourselves, is this due to is this really due to the fact that there's some funny energy out there that leads to the accelerated expansion of the universe? Or is this just a sign that we don't understand gravity as well as we thought we did? And maybe we're using Einstein's theory of general relativity

to describe what happens on very large cosmological distances. But maybe that's not the right description. And if we use a slightly different description, we could make sense of what it is we're observing. So that's why we wanted to explore again, this idea of massive gravity, knowing that the typical theories fail, and there were many, many,

many different ways to show why it was failing. And so we thought, maybe we can think of extra dimensions and come up with that possibility, and thinking that maybe the accelerated expansion of the universe is not, is not really some dark kind of energy being present in our universe, but it's just the signal of what is happening along the extra dimension. So the work that you're doing at a large scale, would it in a way render dark energy a non-factor? That's right. It would be an alternative, in fact, of dark energy.

And what it would mean more concretely, what we're trying to do is use not completely, we will still need some kind of energy out there, but we we can just use the energy which we think should be present from the quantum fluctuations of all the particles. So all of the particles, they are quantum fields and they can pop in and out of existence. They are quantum fluctuations in and out and we see them everywhere in the labs. We see that in everyday life that there's also quantum fluctuations in how they interact with one another.

But we also think that even without them interacting with one another, there should be those quantum fluctuations and that carries energy. And so from that energy using a modification of gravity, we could explain the acceleration of the universe. What was the, when it did like stir controversy with you coming out, I guess, with like building upon this theory, what was the nature of the pushback? Did they go straight to some of

the assumptions you had made where you're like, wait, this was obvious all along that this was wrong and try to dig in on those things and try to make an argument that those assumptions were actually correct? So it went to different stages. I remember we gave a talk and some people raised their hand and said, oh, but there's no theorems there. And so your theory is wrong. So that's why. And so why does your,

what makes your theory not satisfy those theorems? And so I think there was a lot of arguments which were based on assuming those theorems were correct and not wanting to dig into those theorems. And so it was for us to show to people what the underlying assumptions had been made on in those theorems and how to make sense of it. And I think some of the challenging nature of that is that people have different ways to picture things and have convinced themselves of sort of the same result, becoming at it

with a different language, with a different point of view. And so every time we spoke with someone new, we had to start to understand what is their thought process and where is it that we can understand it doesn't match and we can change the perspective so that it actually makes sense. Where is it that they're making an underlying assumption? And for each person or for each community in some sense, it wasn't completely obvious to start with. And it wasn't enough to tell them, look, it's written here, black and white, we have a mathematical

proof and that's it. That wasn't enough for a lot of people because we, in fact, we learned to think intuitively. We use the math as a guiding principle, but the more we understand it, the more we can separate ourselves from that. And we have some, an intuition to follow. And so then it's difficult to go back to someone

and try to read their mind on why are you building your intuition from and set that aside and separate the different pieces and convince them that something is actually working in a different way. Were you able to convince some of the harsh critics? No, yes, yes. It took five years. Slow learners. Yeah. So I think it gained momentum as time went on. I think for me, the fact that we had one, one proof that was already something we could rely on. But it's true that when people came up with different proofs, you think, oh, hang on, maybe in fact, there is something wrong with what we were saying. So

where, where is it I should see? Where things don't match. And at every time you go back to what we did, and what they did, and we have to sort of set up a dictionary. And, and within that community, we may convince a subgroup of people, and not another subgroup of people and the same thing for another community. And then slowly and slowly, we could convince more and more people.

But that was for the problem that had been identified from the beginning. Then after that, people came up with all sorts of different. Actually, what I was saying at the beginning was something completely different. Actually, what I had was saying at the beginning was something completely different. And in some cases, it was coming to something quite a little bit more dishonest, because we're not saying that the theory was solving all the problems in the universe in one go. It's not like that. Nothing can ever do that. You're looking at one variable, essentially. Yeah, we were trying, we make progress, but exactly by making sure we can address that

problem and then maybe other problems that come along the way and we're not saying we're gonna solve everything. So I think slowly we could convince people that the first challenge was being taken care of. There was a little bit of, oh, well, hang on a second, what I was saying was something quite different and there's all of these other things you should be worried about,

which in fact, yes, we should be worried about, but it doesn't mean that we're not making progress along the way. It doesn't mean that we should just scrap the whole thing. 100%. Yeah. So we learn. Yeah. What's the next things you wanna look at?

Are you trying to build more upon massive gravity? Or are you trying to look at other variables now too, in your future work? Yeah, for me, I'm, I don't, I'm not wedded to massive gravity per se. I think it was fun for it was fun. Well, for a while, I'm much more on the theory side. And the reality is that that's more where my strengths is more where my expertise is. Now it's getting more to the point where we need to confront it with observations, we need to confront it with alternatives to general relativity, so we need to do numerical simulations, we need to compare with the observation, look at black hole solutions, all sorts

of things. What does a numerical simulation look like? Ah, so already, for instance, for general relativity, it's impossible to have an exact formula describing on paper, describing what the time evolution of two black holes merging around each other will be. It's so complicated. We have the solution for one black hole or another black hole, but two black holes together and two black holes orbiting each other. That's simply too complicated to write down exactly.

I could do it. No problem. You can do it. We're counting on you. Okay. So now that the problem is solved, you can do it for massive gravity. Yeah, that's right. Yeah. So that's good. That's all solved. So what people do is instead they use the equations that we know they have to satisfy, they put it on a computer, and the computer tells you what the solution is.

I'm saying it like that. It's really, really difficult. It's really challenging. So the first exact solutions of this, of two black holes merging around each other, was only done in the early 2000. It took years, really years, to understanding how to simulate it because it's a very complicated system. It's the most complicated system that you can imagine. It has lots of variables. You have to describe how all your notion of space and time is evolving everywhere

while you have these infinitely curved quantities in there. So you have to take care of a lot of things. It's gonna be good. It's complicated. You can do it. Don't worry. All right. You're doing it right now. And so when one needs to happen is the same thing for massive gravity. And you can do it. I certainly can't do that. But you can do it. I certainly can't do that. Do you think that the rapid improvement in AI that we're seeing right now is going to

completely change the game and how you're able to not just hypothesize things, but actually test it? So, yeah, that's interesting. I think it can help. It can speed things up. But it has to learn from something. And so it needs to have some solutions there to learn from in the first place before it can actually start generating more non-trivial solutions, for instance. Could it learn from... I don't want to say this in words to make this make sense? Could AI continue to become so smart though with interpreting data that it could learn

from data subsets that we have in the past to make conclusions that we haven't been able to find ourselves? So for that, it's tricky when it has to learn from variables it didn't yet know existed. So we can certainly use, and we do use AI to already speed up some of those simulations and being able to find solutions in different ways. And we are doing that. This is something that is a field of study

But it's it's it's almost as if if you don't know what are the new variables is it it is difficult to add on Something new if he hasn't actually got the chance to learn from it So it's like if you are used to seeing the world learn from it. So it's like, if you are used to seeing the world with some given colors, and now it's going to be difficult for you to invent a new color, because you can't think in the world in with those different colors, and you can superpose them and you can paint in many different ways. But I don't even know what it means to invent a new color for you.

Yeah, it doesn't mean you can't conceive it. You can't conceive it. But in terms of AI, it also means that you need to enable it to add a new variable in a new space. It's an extra dimension. And so for that, it is for us to enable it to do that. And so in some sense, we still need to have some of that guidance being there. Otherwise, it can't just pop in an extra thing out of existence. So it almost, maybe I'm making a huge stretch here, but under that logic, it would appear that AI needing us would be evidence against it at least anytime soon becoming sentient. Because sentient would mean it can sense the world around it and it

doesn't necessarily need a human being to give it inputs and tell it what to do. So it depends for what you want it for. But when it comes to discovering new things beyond the box, I think it it becoming more challenging because it really requires setting things outside the given parameters. And in fact, we are pretty good at that. We come up with a lot of creativity in this, but AR is set up with some given variables. It doesn't mean that it can't definitely within the framework in which we're working, set up something which will see something different as compared to our current paradigm.

It can definitely do that, but we still need to set up some variables that we come up with. Yeah, it's just amazing to me like how fast before our eyes it's moving, like with its capabilities, even if it's based on the inputs and everything, like you look at where something like mid-journey was in 2023 versus what you can do with chat gbt 4.0 now. Straight away. Oh, it's insane. So that exponential curve, it's a scary new world. Because obviously, like within the real world, beyond science, it's also going to affect everything we do. Like, does this type of job not exist anymore?

Like out of thin air, does that type of thing not exist? What does that do to civilization and economies and people's happiness? It's a really tough thing. But you see these arguments from a lot of scientists saying this is the single greatest invention of mankind to this point. I could see why they say that.

I'm not saying they're right, but maybe. Maybe, maybe, yeah. Depending where it goes. Yeah, yeah, yeah yeah yeah well if you can solve all my problems I would have done do you like going back to the concept of time though do you ever play around with what it would look like to be able to time travel and do you think that there's any theoretical physics that could point to that being possible so I do I do in many different levels. I mean, you can think of it in different ways.

Like we were talking to start with, even if you go in different places, the way you experience time is different. And so you can go somewhere and then come back here and you have actually traveled a thousand years in the future here, but then you can't travel backwards. And that is scientific.

You can think of this. You can think of things like, again, extra dimensions. You can think of being shortcuts through extra dimensions in the universe. And this is not necessarily traveling backwards in time, but actually doing lots of things that you would have considered being impossible and going much faster between two points. Right, right. In our universe. You're talking forward, though, with these examples. It's always forward. Yeah. Yeah. Going backwards in time. We explore

the possibility, but it's but making it work without everything as we know it falling apart is impossible. So we can't think of situations where, for instance, you can have, let's say light, that you would have identified, we would have identified as traveling faster than light. So it seems silly for me to say that light is traveling faster than light, but this is as we would have otherwise identified it. And I can think of this in how it interacts with quantum, with other quantum particles in a space time.

And there's all sorts of funny effects that can kick in. But those effects are always so so small that I can never use those to end up with a situation where I actually travel sufficiently fast faster than light for a sufficient amount of time that I can then use that between different observers and having a situation where someone else would have the impression that it's going backwards in time. So this is just really just at the purely pragmatic me being a theoretical physicist.

If I go through things, we can't make it work. We simply cannot make it work. Does it work? And this, I guess it's like cheating with the concept of actually going back in time as we know it where we are right now. But if a multiverse existed, does it work? Meaning, if you travel between a multiverse right now, it's 2025 here. But in another version of the multiverse, it's 1944. So I don't even know what it means to travel between different it's 1944. So I don't even know what it means to travel between different versions of the multiverse because that's slightly different than a universe with extra dimensions where you could have different surfaces on these

extra dimensions and they all connected with gravity. But the multiverse is different realizations of the universe but But in between, there's no space time. There's no nothing. So I don't know what it means to travel between them. For me to go from here to somewhere else, I need to go through space time. I can't just pop into a new universe without going through space time.

So I don't even know what it means. Do you think that something like that could exist though? A multiverse? Yeah. Definitely, yes, but I think it's... Because there's no way for me to probe it, I don't know... whether that's anything to do with reality.

It's not connected. Anything to do with reality. It's not real. I can imagine it, but I can't connect with it. I can't communicate with it. I can't probe it. I can't see the consequence of its existence. I can't just pop in there

and look at what happened and come back, but I can't see the consequence of its existence. I can't just pop in there and look at what happened and then come back, but I can't do, it's unlike the black hole where in principle, that's the last thing I would ever do, but I can imagine myself falling into a black hole and I can do that. But for a multiverse, if I think of the universe we're in, it's completely disconnected.

It's another possibility of what another universe would be in that multiverse. And I can't communicate with it. It's just a different realization. So what does it mean? I can think of it, I can imagine it, but... Purely theoretical. It's purely... It might as well just be purely theoretical, and there's no distinction between it being

purely theoretical, and being any connection with reality. There's no distinction. There's nothing I can do to ever prove its existence. Is there any evidence or experimentation that leads to? No, no, no. It's kind of more of aall if maybe something goes wrong. So where it comes at one way to think about it is to say, if you're in string theory, there's so many different possibilities that could have come out of it.

Maybe a lot of them got realized, and we just so happened to be in one of them, and we just so happen to be in the one, in one of them that is okay for life, and where galaxy got formed and everything was just so that we can be there and ask ourselves the question. And in all of the others, there's a huge number of other ones where the conditions were right. And so they aren't little human beings out there asking themselves that question. And that's fine. We can live with that. I can imagine that. I can accept that. But I can't make it reality. Yeah, you can't prove right now that if you turn the transistor a little bit in this room, it was dinosaurs instead of us. That's right.

There's no way. Yeah. That's right. Yeah, purely theoretical. It's interesting though, because it would explain potentially, it could explain the little quote unquote unexplainable things. Like why do we get deja vu or something like that? Or why does like, why does someone think of one thing, you know, sitting in New Jersey and another person that they know is thinking of the same thing at the same time sitting in California. Like, maybe that's strictly some other type of explanation. But maybe it is there's some sort of weird like momentary

shift between the dimensions, if you will, that just if they were, that would be great if they were because that gives you something tangible to test. So if you think, I don't think, but if you think things that seem surreal for us can be explainable through those things, it actually means there is an element of reality, there is an effect on us and we can latch on that to make an experiment, make some predictions and test if they're right. Maybe we'll be able to do that. I'll be there for the test. I wanna test the multiverse.

Maybe the fact that you're thinking about it is just- Maybe that's gonna bring it about. I don't know. That's why we're doing this podcast. Think about it hard enough. That's right, I'm gonna transport into the middle of the table right here. But you also, I read you actually looked into becoming

an astronaut yourself. And doing some things that are related to actually exploring some of the science you've devoted your life to. So why didn't you, I think at some point, you got sick or something like that, so you had to drop out? point, like you got sick or something like that? So you had to drop out? Yeah, I never got sick in the end,

but I had, indeed, I had latent TB. Do you know what latent TB is? Is that tuberculosis? It's tuberculosis, but in fact, latent just means that you've been infected once in your life and your body resisted it. So it's not necessarily a bad thing. But it's within you. It's quite common. I don't know about the US but throughout the world, it's

really very common. A third of the world population has been infected at some point. I didn't know that was still like the case. Yeah, I mean, in some part of the world, TB is very, very present still. And so I've been living in different countries. It's perhaps not so surprising in itself. But you went to actual, it was in the European Space Program, right? Yeah, the European Space Agency. And so every, they had actually in 1919, no, sorry, 1920 or 1921, I don't remember, 1921 they had an astronaut a new astronaut selection but the one I applied to and I went through was in 2008 2009 so it was a long process of call for

astronaut people apply and there's a whole year long, more than a year long selection program. And what does that look like? So there's a lot of psychological test and team working test and stress test. Psychological test with different people trying to check. Really, I think the main thing is you want to check are you gonna be okay out there?

Are you gonna be okay out there? Not just for a few minutes, but potentially for a month. And sometimes in situation that may be quite stressful and are you gonna be working with the others to make it okay. Or it just... They need people like not on Klonopin or something. Yeah, that's right.

So somehow they thought I was okay with that respect. And then there was, there's also some logic tests and some, in fact, some physics tests, but more some IQ tests and a lot of stress tests, putting different people in a situation where it could be perceived a bit stressful and they have to communicate with one another to get out of it. It was fun, in fact. So more than 8,000 people applied. And as the process went through, you

could see that the people that were going down, they were really nice people. They were really thinking. You could be with them in every room for six months with quite challenging condition, and it'll be fine. You could really rely on them. So they definitely did something right through the process, because in the end,

I was with the last 42 and they did groups of people. So with a group of seven people where we had very intense medical tests. And that's where they found this. And that's when they found it. Yeah. What did that feel like when they told you? So throughout that week, I went to all sorts of tests, you kind of mentioned they do all sorts of things, they really want to make sure that it's not just that you're okay right now, but

they're not taking any bet into training someone for decades for 10 years possibly, and then they'll end up with a condition. So they really want to make sure you're okay. They do all sorts of tests, which are quite intrusive. So they really want to make sure you're okay. They do all sorts of tests, which are quite intrusive. So the whole week was really, really intense. And by the end of the week, I had a chat with the doctor in charge. We went through all the results and he said, oh, everything looks really good. And it was the first time I thought, wow, maybe that can work out. it. It was the first time I thought, wow, maybe that can work out. And he was saying they actually need a woman and it would be good. So I thought, okay, he said, we just missing

for one, we just missing one test. I'll send you the results as soon as I have it is the DP TB test. So I thought, oh, that's fine. Good. That's fine. I don't have. Have you seen me? I don't have TB or coughing. I'm fine. So I left and it's not like I thought, okay, this is this is it. But so maybe there's a chance for this to work out. And then I was about to board the plane. And I got a message from from the doctor saying, here's the results from the TB. I'm so sorry. So yeah, it didn't feel great.

It didn't feel great. But it was very clear. It wasn't something where I thought, oh, if I trained more, I could have done it. If I'd done anything differently, I could have done it. It's not like that. There's no failure or anything on your part? Well, it did feel a little bit like a failure, but...

But it's a health test. Like, what are you gonna do? No, there's nothing you can do. There's nothing you can do. In fact, I think if you had been something psychological, I'd think, oh, wow, I'm not a very good person. I should have been nicer or whatever. You can always blame yourself. And of course, you can blame yourself, but that's just the way it is.

It's not like I could really have done anything about it. So you just have to pick yourself up. And in the end, things turn out quite differently as compared to what I would have expected, but things are fun. I'm having fun every day. Yeah, you're doing a lot of cool shit. Yeah. Yeah. Yeah. But do you still, especially like with private organizations, like you've already referred to today, doing some space trips,

do you still still dream of doing that? I think it's less for me. I really wanted to be out there for months and, and in fact, pushing research, pushing something for a little bit more for science, not that I don't want to go into conversation of what is worth, what is not worth to before me. I would have wanted to do it like that. Right, not six minutes. Yeah, yeah, yeah, yeah, yeah. Maybe maybe we can get you up there for a month though. We'll find somebody. Okay, do that. Yeah, we'll work on it. I'll see who keeps sitting in this seat. Okay, yeah, yeah, do that. We'll find out. Do that, do that, yeah.

But you know, there's also, you know, not just across podcasting, but across the whole internet, it's a question that people look at all the time, which is, all right, what else is out there? Yeah, yeah. You know, we have intelligent life here, we have humankind and a lot of other biological species, and then we look in our own solar system and, you know, there's some where it's like, all right, there could be a little life on that planet right there, but there's nothing that shows that there's, you know, a species like us living here.

But then we know we're a part of a galaxy, which is a part of a universe, it's potentially infinite in size, which means that the probability mathematically that there is some other form of intelligent life out there is very, very strong. And, you know, if you ask me, it's like, well, it's got to be like 100%. But it's a whole separate question when you start talking about, well, have they been to this solar system? Or have they been to our planet or anything?

Do you view that as any possibility that that could have happened? Have they been so far? Yeah. Well, we haven't really seen anything. We haven't really seen any evidence. I think the probability that there's something else out there is really high.

But now, when you account for the fact that they need to communicate with us, they need to be living within a time frame that makes it possible for them to communicate with us. Of course, there's life on Earth, but actually, we only been living on Earth for a very, very short amount of time. And so now you imagine we need to coincide

with another life being within the right amount of time and also in the right distance so that can be possible. It's just, the distances are so, so large. And I don't think we can travel faster than the speed of light. So it takes a long, long time. We can. No, we can, but I don't think, I don't think anyone can.

I don't, so I'm very open to there being another civilization out there in here, in this room of dark matter that I'm very open to there being another civilization out there in here, in this room of dark matter that I'm very open to. But for them to travel faster than the speed of light, I don't see how this is possible. My pushback without any real scientific expertise, obviously, would just be in a general form of how could we know that if we're only operating with the knowledge that we know here? Like you're at the highest, you're at the tip of the spear at this, the highest level, but hypothetically, you know, the greatest scientists we have on this earth right now could be the ants to some other civilization. It's like, ah, speed of light, we figured that

shit out a thousand billion years ago. So please prove us wrong. It will be amazing. And I think you can find, you can do other things. You can find shortcuts. You can find all the ways. But traveling faster than the speed of light, it's not that we only understand what is happening out here, right here, right now. We do understand very well how the whole universe has evolved

and how it got to be the way it is. And we understand that things on the other side of the universe, look in a particular way. And so it's not just about things, how things look like right here, it's it's how we connect with all of those different things. And so if there was anything else I had discovered, or find a way or even if they hadn't found a way, but if there was a possibility of traveling faster than the speed of light, the consequences of that

would not just be little subtle things that we haven't yet discovered. They would have a huge impact in our understanding of the structure of everything. Oh yeah. So it's very difficult to reconcile that with everything else we understand. We would have to change completely all of our understanding of physics if it was possible

to travel faster than the speed of light to an amount which is actually useful. And no one, us right here, but no imprint on any galaxy, no imprint on anything else, on any of the temperature of the sky, on anything else would have been discovered. Wait, why is, why wouldn't it have been discovered? Because being able to travel faster than the speed of light, even every so slightly, enables you to being able to travel backwards in time as well. You can start doing all sorts of different things. And so it opens a whole new realm of possibilities.

And the ways we are thinking about the laws of quantum probabilities, for instance, and how they adapt together and all sorts of things, they rely on, they rely on some laws of physics and what I like to call unitarity. They rely on some guiding principle that does require some guiding principle like not being able to travel back in time.

Theoretically though, this is strictly, no, no, no, no, no, absolutely absolutely what I'm about to say yeah this strictly theoretical if we were operating in a scenario where I'll even say our full universe not even just galaxies but let's just go crazy and say that you the universe were actually some sort of created reality of a higher species yeah yeah where whereby they created the speed of light. So that's nothing to them. Yeah, right. Then hypothetically, if that were the species who were

somehow then sucking down into this world that they created, and like, more than in almost like, what's up, fam? Yeah, then it could be possible. But what you're saying, if I'm understanding it correctly, is it would have to be something like that, rather than something emanating from within maybe even our galaxy. That's right. But in that case, I might as well, I'm just doodling in that case. And we all, all our sound effect reality is just doodling because it would just mean that

we're trying to find patterns, but those patterns, they're nothing to do with anything real. They've just been what the computer programmers have set up so far, and because they decided so, and at any given point, they can change the variables and it's going to be completely different. And so everything that we learn, there's no logic to it. And you may as well just disappear. On that note, my brain is melted from today. But Claudia, I love having people like you in here because you have a beautiful mind. And the way you look at the world is so cool and obviously incredibly meta for guys like us who aren't in there testing the theory of gravity every single day. It was fun. It was fun. Thanks a lot.

But thank you for coming and for changing your schedule to be here. But we will have the link to your book down below that came out last year, I think. Right. And you go through your whole story with gravity and everything there. But we're gonna have to do this again at some point. That was fun. That was fun. Let's do it in outer space and then we can try also some things. We're gonna call up Jeff and make it happen. Yes. I got him on speed dial.

Yeah, do that. All right. Thank you so much, Claudia. Thanks. All right. Everybody else, you know what it is. Give it a thought. Get back to me.

Peace. Thank you guys for watching the episode. If you haven't already, please hit that subscribe button and smash that like button on the video. They're both a huge, huge help. And if you would like to follow me on Instagram and X, those links are in my description below.