Gravity Physicist on Intelligent Life, NASA & DARPA Anti-Gravity | Claudia de Rham • 310

Transcript

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

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? and multiverse. Yeah, 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 subscribed, please smash that subscribe button and hit that like button on the video.

And if you don't have time to watch this episode right now, no problem, but I'd really appreciate it if you would save it to your watch later playlist. Finally, if you'd like to follow me on Instagram and X, those links are in my description below. 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 um south of Manhattan. Oh, you got to see it.

Yeah, I got to see uh uh Liberty Island. Yes. Yeah, it was beautiful. Yeah. Thank you.

It never gets old when you see that. You look down. It's really nice. I was on the right side of the plane while I was on the left side of the plane, which was the right side of the plane. Yes.

Yeah. You look down, it's I always think about cuz 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's It was crazy looking at it. Wow, there's so many of them.

But yeah, it was good. Now, in your world, does that exist or is spaceime not real? Well, we can use it up to some extent if we really have to. Well, we're gonna get into it today because you're like one of those like my brain explodes. No, you're when I hear you talk. 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 and 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 dream news. Oh, you're dreaming about the formulas, not like the fun stuff. I mean, it's all built in.

It's all you think it's like Legos, right? You're thinking about the structure and then the formula. You have to think of them as the little pieces you put them together. So sometimes it's like you have this little piece and you're trying to understand where you're going to put it. So if that frustrates me and it comes to you in your dreams. That's sometimes in my dreams it always 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. I'm sure.

Let me go back to sleep. I'm sure it's going to be fun. Yeah. Yeah. So I actually I got introduced to you through my friend Kurt Mongol.

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 that 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. Huh. He's very technical.

Kurt's smart. Yeah, he's great. He's amazing. So, I did I did another podcast with him two weeks ago. Oh, you did? Yeah.

I didn't see that. Uh it just came out. Okay. All right. I'm going have to check that out, too.

Yeah. Curt's extremely extremely well read on all this stuff. He's uh he's uh up there. That's that's a very good endorsement, by the way. He should play that like for his uh for his real like Claudia Durham.

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, you know, know the story about Isaac Newton and the apple fallen and that's gravity. But we just think about it and 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 uh we can get stuck getting technical there, but one thing already with his story with Newton, it's not so much about the apple falling on him and hurting him, and that's really funny, but 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 laws 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's something which we're experiencing right here on on a particular scale is in fact exactly the same phenomenon that governs the 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 we can go into the details but in fact the whole universe is what is it? It's is space time and so gravity is spacetime.

Um so it is the whole universe. Gravity is really the fundamental law that governs anything that you that you want to think about. Um 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 by the sun and we have the impression that is not falling directly towards the sun but it's still feeling the gravitational attraction of the sun it's just imagine um I take 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 very fast. So, it's not going to it's going to drop in a little bit. And if I were to drop to to throw it faster and faster.

Yes. 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 just went into space for six days and all them 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 that's what falling is. That's falling.

That's falling. So if you're thinking of an apple falling or if you think think of yourself falling just during the fall itself, you're not going to feel anything. M and 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. It's just that fall doesn't stop.

You keep on going and going and going and that's just amazing. It is you can imagine. It's what keeps us alive, too, cuz we're not falling actually into the sun. That That's why that's a good thing. 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 and not floating.

Well, I wasn't really to bother about the Earth itself. I was more thinking about the stars and and the planets. So, it was more trying to understand what's our place what's the place of the earth here in in the solar system in in the universe. But I was very small. Yeah.

I think I think we all I think we all interested in gravity. I think I think you can I can see you're interested in gravity. Yeah. Yeah. Um I think we all play with gravity to start with.

We all throw things around. We all try to see if it's going to keep on falling down, keep on breaking down when it reach the ground. Um and I think so we all do that and 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 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. Um but I think we all sort of question 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 um 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? Um, probably around 10, 12, something like that. Um, but looking in the science behind it, it's more reading about it and and understanding what it means, what um without you don't need the math so much. Um, you don't well to understand the concepts, you don't need the math. Then then if you want to actually um interrogate things and make predictions then you start needing to have formula and need to be more precise and that I don't think I ever did before I was uh a teenager when like everybody else I was going to say that gets very complicated too. I I don't think like at 10 you got to be special at 10 to be doing something like that.

But it's 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 neverending 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 right. That's what it's exactly as you say. It's really a pathway and it's a journey. It is being part of the journey. And maybe your contribution isn't quite right.

May it's certainly not the end of the story, but we we're trying to get somewhere and exactly where we going. We don't know. We don't know. But we we're trying to understand. Yeah.

And it of course it's all theoretical. A lot I haven't been in space. I don't know that uh I haven't gone and measure things in outer space for 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 going to start looking here and I'm going to make this very very precise observation and this is what I should be able to see and that's why 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 um vacuum chambers underground. Um and then I'm going to have some mirrors which are located 4 kilometers apart. Um 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'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 our gravitational waves which is coming from the merger of two black holes located millions of light years away from here and please can I have some funding from that and and people build that and that's what they observe. Do you know that when gravitational waves pass through the earth, they are stretching space between those mirrors in those cavities which are 4 km apart by a distance which is smaller than the size of a proton and that's something we measure. This this is something we could predict and we have measure and the way the signal behaves is exactly as one would have anticipated.

So it's 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.

But there's also and and I don't want to 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 like 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 like I get it because they haven't been able to ship a test on that, but the concept like when you wish and when you listen to Dr.

Kaku like explain it, the concept makes a ton of sense. It would make sense. You know what I mean? Like what do you think of string theory? Ghost bed sleep so good it's scary. And in the middle of the summer, there's nothing scarier than waking up in a full sweat wrapped in your sheets like you just timeraveled back to your old high school locker. We've all had those nights.

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Well, some of the work that I try to do is to try to understand if we can in fact prove string theory wrong. Not because I think it would be wrong. I I think it's amazing. I think it's it's the most concrete potential uh formulation of what could happen beyond our understanding of space and time. So, so I think we should really take it seriously.

Um, but it would be so cool if there was a was a way to understand whether it could be wrong and what it would mean. And when we say string theory has no has been disconnected from reality, I don't think that's entirely true. I think um there's been a path I was given for for some years and it hasn't materialized the way one would have expected but it still relies on understanding of how physics has to be realized um in some in some context at very very high energy and that still has some consequences for things that we can observe within our experiments that we can we can play with today, tomorrow and so they are potential test that one can do if 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 don't know. I think it's 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 uh game in time at the moment.

There's not really any other concrete way to formulate things. Um the fact that it's very challenging to get some uh concrete observables out of it is is disappointing, but it's also that's sometimes the way it is. Um but in the way the research that I do, I try to remain relatively agnostic in the kind of high energy completion um what happens beyond our frontiers of knowledge um that we could have and I think it's 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 it's been a the the issue I think in academia where 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.

Like 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 like as a mathematician lens but smart stuff. I I just don't I'm not smart enough to speak on the evidence there, but it's like a lot of 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 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, it's like you said, it's best game in town and people therefore who come into question it. It's more like, ah, we don't want to deal with that. Do you think that's a fair way of putting it? It depends a little bit on who you who you ask. Um, that if you ask the people that are 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. Um I think there are aspects of string theory that have actually been a huge success like what uh just for instance the 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. Um and a lot of the when you compute when you compute some lows of probability that's the way it works the quantum world works through laws of probabilities lows 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 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. Um some of them they come with with for instance extra dimensions. They come out with a lot of luggage along the way. Yes. And then you need to deal with all of this and 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 in keep working and making progress in in string theory. But it is true that uh 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 uh to make progress in that. So a lot of string theorists now they work on slightly different questions of string theory like what um for instance have you heard of um holography? I don't think so. No. Okay. That's a I'm not I'm not a string theorist.

I'm not an expert in holography by any stretch of a measure. Today you are. Okay. Um so one of the cool thing that came up from from strength theory is the realization that you can think of um gravity. You can think of a system which is gravitational.

You can have black holes. You can have all of these really really cool things that come out of of gravity. Um but in fact all of the information about that is encoded on a projection. projection and a projection. It's a holography.

It's it's a hologram. Um, now the geometry of that is something you may not have heard of. It's it's called anti the sitter space. Definitely haven't heard of that. So, you should write it on your Yeah, we'll write it on the next mug.

I still won't remember it the next time, but keep going. Um, so that that that's just a little aside. Um but you can have you can think of um where gravity is as being a spacetime which has a boundary and the information which is on that boundary carries as is as relevant and can from that you can derive all the quantities that you want. you can derive all of the observ equivalent observables as you would want as compared to a theory which would have gravity in what we call the bulk or or the fullyfledged um extra dimension theory. So you can have um a theory of gravity which is in fact completely equivalent to another model without gravity of fields which um may satisfy some specific properties with some specific symmetries in one lower dimension.

So that's uh projection and there 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 of and with which we can make a lot of um progress in terms particularly in terms of calculations and particularly in terms of understanding what happens when the system becomes so complicated. it it interacts with it with itself so much that it's hard to keep track of everything is doing and so you need to have a slightly different perspective in how to look at everything and you can do that and and people are even nowadays making connection between that and systems which are condensed matter system like real physical system that um don't involve gravity at all and yet they have some description which I drew fuel 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. And 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. Okay, come back for sure. Okay, let me let me stop there. Uh we can go back to to black hole information and and all of that because that's going to attention. But all I'm saying is that there's a this is the way science works, right? You you have 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 and you do you do have a much better picture of what could go beyond our understanding of space and time.

Um 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 that's how you make progress and you need to keep on exploring. You need to keep on exploring all those 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 it's it's a scientific research is going forward into probing what what is possible. Mhm. The graviton part though, you said that came out of this too.

Yeah. When when did that happen? And can you explain the graviton to people because we're going to that's at the at the center of massive gravity and and the things you work on as well. So it's going to be important to have that context. Yeah. So um we celebrated 100 years of quantum mechanics this year.

We did. I missed it. Sorry. Happy birthday. Yeah.

So um to understand the graviton it's it's it's useful to to combine a little bit uh gravity and quantum mechanics. But let let me let me start with something slightly different which hopefully is a little bit more familiar which which is light. We're all familiar with light. Hopefully we're familiar with light and light is a wave and light light is an electromagnetic wave. um it's just a fancy way to say that it's um there's a field which is an electric and magnetic field and and when light comes from from everywhere it's actually um some vibration in this electromagnetic field and light comes in with a particular frequency and carries some energy and in principle the light in this room you could say um 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, there would come a point where you will start saying that it's it's not continuous.

You can't completely dim down light to um as much as you want. There will come a point where you realize that light is actually carried not by something you can dilate 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 and those photons they are the carrier of the electromagnetic wave. They are the carrier of light. um photon are the particles responsible for electromagnetism and you can even think uh in fact if you have um two electrons or two charged things um so we all know of static for instance if I were to to do static with my hair every morning I do that I got to like wet my throat it's crazy so you know about that um you you can you you know that there's some sort of force at a distance and you can ask yourself fundamentally How how high is this force at the distance uh transmitted? What is the carrier? What is the fundamental messenger of the static of the electro electromagnetic force? And fundamentally it's a particle which is the photon.

That's a fundamental particle and we understand that very well. Uh 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. Um there's an analog of light for gravity which u an analog of light. What does that mean in English? So light is related to the electromagnetic force. Yes.

And and so that force I can think of instead of the electromagnetic force I can think of the gravitational force. Okay. And so if uh the electromagnetic force has trying to wrap our brain just keep going today. Trying to wrap our bra and I were looking at each other like did you get that? Nope. I'm like just keep going.

By the way, we have Gio Gussen in the studio today. Longtime friend of the podcast. But please continue. Go ahead. Tell me what you got.

That's so picking up the pieces here. He's going to start shilling NFTs if we let him 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 a scratch course on on string theory and then we go on that.

Yeah, we'll get there. Um, okay. Let me just say um if you think of electricity, if you think of the electric force, you know, you know about the electric force um there's something that transmits the information between two electrons. If you know they're going to 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. Um, how do you know what is carrying the information about that force at a distance which is a gravitational force? And so fundamentally the carrier of the gravitational force, a 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 um 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 um go beyond Heisenberg and sanity principle with current experiments. So, it's too small that yeah, it's too weak. It's far too weak. Um 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.

Um this is a shaking of those mirrors in interirs. This is a passing through of gravitational waves and they those gravitational waves are actually in fact granular. We don't see that they grind a lot because the the the pieces of sand that would make those gravitational waves are so so so tiny. But if we were able to zoom in into those 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 uh gravitation um Einstein's theory of general relativity instant theory of gravitation was 20 195 1915 and quantum mechanics uh came about 100 years ago very naturally already by um 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 amazing. It's been known that there were those fundamental particles. That's amazing that that long before like a computer for example.

Oh yes. 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 100% right or anything they're in the right direction it's amazing yes yes who were you who were your scientific heroes growing up like did you have any in particular um no I don't I don't think so yeah I don't think so I can tell you my scientific hero right now would be Emmy have you heard of Who? Amy Nusa. Amy, is it n u ss e r? Last name? Uh n o e t h e r. N O. That's her.

Okay. Oh, she's dead. Oh, yeah. She's a bit dead. Yes.

Okay. All right. Oh, yes. I thought you meant like alive. Yeah.

You want you want to invite her to your I was going to say she's really she's really dripping right there with style. That's like a real throwback. Anyway, all right. Can we go to the bio? Let's let's let's give her proper. All right.

So Amaly Nother was a German mathematician who made more many important contributions to abstract algebra. She also proved nother's first and second theorems which are fundamental in mathematical physics. Notther was described by Pavl Alexandro Albert Einstein Jean Diodon Herman Wei and Norbert Weiner as the most important woman in the history of mathematics. As one of the leading mathemat mathematicians of her time, she developed theories of rings, fields, and algebbras. In physics, nother's theorem explains the connection between symmetry and conservation laws.

Translation, please. She's great. Clear. I mean, she she's she rocks. She's got rocks.

Yeah. But what is what is this thing? She explained that she her theorem explains the connection between symmetry and conservation laws. What does that mean? Yeah. Yeah. So uh let me say concretely we we all have this inbuilt notion that energy should be conserved.

We we 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 or something else but we like the notion to think that energy is conserved that that's why we call conservation and in fact this is a luxury that we have in most of of our everyday life but it's not true in reality it's not true in the universe we only have that that 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 you can take a system and you can transform it and it remains invariant do do you see what I mean by that kind of it means things remain the same um and so if things were oh invar I thought you said something different okay is my English now you have no your English is great I just heard it the way You say it way cooler. You say invariant. So I'm like, oh yeah, invarant. Invariant. Yeah, you're in New Jersey.

You got to bear with me. Um, so you have my English, your max. Good luck. Anyway, that last part though, just repeat that one more time. So what was invariant again? Uh, I forgot what what was it invariant? Sorry I did that to you.

Um, so you only have energy being conserved. Yes. If the system itself is invariant and and invariant so in fact in the universe things are not the same as you evolve in time. You don't have that symmetry. It's 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. Uh luckily otherwise we wouldn't be there. And so we don't have this luxury of a conserved quantity associated with 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. Um but what Emmy Nurther realized is that 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 a system which um 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 lens. That 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. um all of um 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 are inbuilt in all 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.

That's right. Yeah. So he has a huge respect uh of her. Yeah, I don't I think I don't even know that this make it complete justice to her because I think she he considered her much more than the best female mathematician. I think he really had a hu much more just the best mathematician in general possibly.

Yeah. Scientist. Yeah. Yeah. It's clear.

I mean that's I I I don't know about her. So I got to do some more research. Yeah. Yeah. We'll invite her on from beyond the maybe AI will let us do it.

We'll have you sit in as I mean know make people believe but what just just at a base level because it it formulated much of the work and 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, so maybe to get there, sorry if I'm if I'm a bit slow. It's even he he did so many different things and uh it may be useful to go through all the different things he's done. Um we know him, most of us know him through this formula E= MC². Yes.

And so this this already is incredible. It's 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 um 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 it's a different way to think about how we 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, so if you take light and you shine it, it travels at a given speed, um, 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 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 counterintuitive. This was counter any of the of her understanding of how how the laws of physics should change when uh 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 are experiencing one second passing by I should agree on that and in fact we don't need to agree on that is 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 the one where they go to space and time changes. You know what I mean? Yeah. So that's a second effect which is related to the gravitational effect to the curvature of space. That's a second effect. But already in 1905 he realized that and that's not to do with um whether you're close to a black hole or not for instance or whether you're close to the surface of the earth or far away.

It's simply related to our respective speed with respect to one another. M so if you were to run a marathon at a constant speed since the beginning of the universe uh 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 counterintuitive we think that's not fair and yet that's the way it is what is I actually don't understand this so if I'm running a marathon if you're running you're just running you're at at you at a given speed with respect to me we're not going to agree on the 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 cuz like when I I I do a plank every day at the end of my workout, right? And I usually hold it for like a 100 seconds and it feels like [ __ ] 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. It's a different phenomenon. Yeah.

You're saying it's literally different. It's 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 um how much time they feel and and you can ask that because atom may decay through radioactivity for instance. they may decay and 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 um 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 and in your scenario they're experiencing time in a different way. When they stop they get across the finish line. Now does now did the atoms almost go. So no they don't they don't but the reason uh 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 a deceleration what happens when you speed changes and in 1905 Einstein came up with a theory of special relativity where the notion of acceleration wasn't yet built in fact now we know that there's a well he knew there's a complete equivalence between feeling acceleration and a gravitational attraction and and I don't know if it's you can feel that but if if you if you actually try to 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 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 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 accelerating pushing me constantly pushing me. The feeling would be exactly you wouldn't be able to tell the difference.

It doesn't like pull you back to your seat like that. But but you No, no. That So that's just a a question of direction. Yeah. Yeah.

But the direction can be exactly the same. And but we know that you Oh, relative to the ground you're on. Yes. Got it. Okay.

So, we all seen I'm sure you can see some of those science fiction movies where um there's um cylinder uh rotating cylinder and it makes artificial gravity in some of those uh um in what is it? I know some of those uh science fiction movie. You know, you are in in this uh in outer space in the middle of nowhere and you have this cylindrical object. Oh, it's in like interstellar where it's just install. Yeah. Okay.

Can we pull up go to the beauty of interstellar on YouTube? Allessie, you can tell I've used it before. Yeah, exactly. Exactly. That's why. So, the top left one.

Yeah. And if you actually Can you go back for one second, Le? That one's a good example, but I 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 the one I was thinking. Yeah. Yeah, exactly.

So, so they're far away from anything. There's no earth there. It looks like there's just a cloud of um of dust or something like that. Um but let's ignore that. It's just for visual effect.

I think they have it there. 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 it 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 the the gra it might have been called like the gravitron. Right. That's what cuz before Gio and I were talking and I'm like yeah this lady works in gravitrons.

It's like it's gravitons, you idiot. My god. Yeah, he was right. That's what I do. So, this is all day long I'm going to But that would it would spin you fast enough and it's not going to like the ma the maximum speeds you go, but you'd be able to eventually like kind of like stand up almost but from the side.

Exactly. Exactly. Exactly. Wow. Exactly.

So, this is telling you that the acceleration can compensate gravity vice versa. So in fact there's a complete equivalence between gravity and acceleration. A complete equivalence. There's a complete equivalence for like an like they I'm trying to think of this correctly. It's almost like there's an offset there.

Hey guys, if you haven't already subscribed, please hit that subscribe button. It's a huge huge help. Thank you. You can offset them. Yeah.

Okay. Yeah. You you can compensate one for another or you can you you you can for instance um think that one is the other one just like now in because it's it's it's all dark in here. In fact, I don't know. You're telling me that we on Earth, but for all I know, you just shoot us out in outer space or we could be in another dimension.

Mu Machu 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, I mean, that goes beyond gravity. That gets to like Wait, is this Oh, that's just gravity. That's all gravity. That's just gravity, too.

That's all gravity. Come on. It's all spacetime. All right. Wait, define spacetime, then.

Oh, spacetime. Yes. Um, do do you know what time is? Yes, I think so. [Laughter] I don't know what time is. So, please explain me.

It's a great song by Hanzim. Oh, okay. Good. Do you have a song about space? No, I I mean like to me time is just it's the it's 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 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? Um, but it's it's relative in the sense that it it's much of a muchness of what time is as compared to what space is. And we don't think of it like that in our 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 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. That's right. That's right. Okay. Exactly that.

So so this is exactly where we're going. when we had um 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 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 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 we have to go even further in how we are thinking of a notion of spacetime. 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 quite fun. It's really really fun in itself and you can experiment with that. But once you start including acceleration or gravity in the game, you all seen this picture, you actually see that spaceime take even some life of its own and can start almost moving moving apart and and you you have you you can think of you you see in those pictures um for instance the the black hole on the yeah this this you can think of it as spaceime. This is spaceime 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 spaceime come into life and and curve and it's not just all boring like 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 this is now this is precisely in this picture where where the the way you experience the flow of time is going to be even more different if you close to a black hole if you're close to something which is very curved like that as compared to what uh 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 spaceime. 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 ais 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 into space at a faster or or at 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. So it's very hard. It's very hard. But but so for me curve space is you can think of it just like the surface of a trampoline and and that is a curve space. You you think of a trampoline, you put a ball in the middle and you see that the the fabric of the surface start becoming curved.

Yes. Now there's there's some issues with this analogy because the the reason it becomes curved is not because so much of the mass being present in the middle is rather because the mass wants to get attracted to the earth and so that's what makes a curvature. So so the analogy is not perfect and the analogy is also not perfect because spacetime is not curved within something else. Everything is spacetime. There's not such a thing as something beyond our spacetime.

Spacetime is everything. There's not a there's not a point where space stops and then there's something beyond spacetime. That doesn't make sense. Yeah. So, so the analogy is not perfect.

But but you can represent the notion of curvature of space in the same way as we may think of the how a fabric is curved. That's okay. But the thing is now want to want to think of gravity when you 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 spacetime and 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 uh the flow of time being different in 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 to the black hole the way your time will slow down as compared to someone which is very far away.

So what is what is there are there are a lot of elements in interstellar which are actually complete science. Yes. It's completely like Thorne was the guy advising yeah and it's completely true. Um, 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 we haven't done that yet.

Well, you can try. Send Katy Perry to do that. Okay. And she'll like it. Yeah.

So, we when did we first come up with the concept of a black hole? Was that right around the same time? It was uh 19 of 1915. Uh um 1915 Einstein came up with Einstein theory of general relativity. He didn't call it that but he came up with that. 1916 it was during the war. Can you imagine? It was during World War I.

Yes. And Schwartzfield was in the war. He was in the tranches. Churchill. Churchill.

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 of the theory came out.

Just a few months during the war in the trenches, he found out black hole solutions. Churchill. Winston Churchill. I was on the same shield. Schwartz shield.

Oh, okay. 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. That's Shield. S um C H W A I can't believe Churchill. This is a great science fiction movie. Right.

All right. So Carl Schwatchchild, a German physicist and astronomer, he provided the first exact solution to the Einstein field equation of 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. This Schwarz Schwarzild solution which makes use of Schwarzild coordinates and the Schwarzild metric name good branding leads to the derivation of the Schwarz child radius which is the size of the event horizon of a non-rotating black hole. So not even 16 15 Schwarz accomplished this while serving the in the German army during what? Well, he lost the war jokes on him. He died the following year possibly from the autoimmune disease PMPUS which he developed while at the Russ.

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 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? So nowadays we have 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. So 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 the black holes are not such controversial in themselves. We we understand how they work.

We understand how they work as you get close to it. As we enter them, we understand how they work. Is 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 theory of relativity doesn't work anymore. Um, but we 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 uh start looking uh at what we see at the very center of our galaxy.

We see that there's a 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 of this correctly? This would be where the sun is effectively.

Uh, no. The the sun is at the center of our solar system. Yeah. Um, and we are our solar system is a little bit on the edge of the galaxy, right? It's not it's not it's not close to the center. It's towards the the edge.

But if you look at the Milky Way, have you seen the Milky Way? Yeah. So, if you look towards the Milky Way and you really really look very closely, um you're not going to see anything. But but people have done uh with instruments. So they've done um with a KEK observatory which is um a series of different telescopes that been tracking stars at the very center of a galaxy and then they've seen that they're orbiting something at the very center of a of a 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 it's not it's not we can't just go there. No. Um so that in itself if we believed in Einstein's theory of general relativity it should be a black hole. Um so then in in the meantime people have looked at how light gets deflected around that black hole and this is a observation from 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. In fact, it's the it's it's the shining of a black hole, if you were, it's really seeing light from around the black hole that is not emitted by a black hole itself, but emitted by objects behind the black hole. M and so by looking at that uh people can determine whether light is following trajectories which is what we would have expected um according to those black hole solutions or if it's completely different and so far is in in impeccable agreement with what would should happen if it was a black hole there. But black hole, the shadows of things on the other side of the black hole, which you know, when we think of 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 a 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 were just sufficiently far away that that they been affected very strongly but but haven't fallen inside the black hole. So they just escaping.

We can see it. We can see it here. Where do we think when it comes to 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 that could make an estimation on that or are we totally unsure? How many galaxies have black holes inside them or or 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? Does it go to one other place? Does it go to a million other places? I I love your question. Oh, you you're assuming this is bridging to something else.

It's an assumption. Yeah. Yeah. We So maybe I think at the moment if you ask most people they would say zero. We don't think it leads to a white hole or bridging to uh 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 short child uh type of black hole as you enter it even the notion of space and time get uh switch into one another.

So just uh like for us when um 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 I unfortunately can't decide where I want to be in time.

It's just going to push me forward, right? And that that's just the way it is. I have to make do with that. Um now when inside the black hole, in fact, you can't decide where you want to be inside the black hole. it'll just swish you to the center of the black hole and you have no choice on it. So this and then the 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 quite crazy as you enter the black hole. You have very little chances of surviving it as as we think of ourselves. um at least I I don't think I would have but 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 theory of general relativity to tell you precisely what happens there it breaks down meaning like the gravity as we know it no long it's an entirely different force even spacetime may be different and 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 spacetime 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, right? Um 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 um 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 um 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 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 um unfortunately I can engineer for you right here. I was going to say like is that even something is that even something we're going to be able to measure like in our lifetimes cuz it we can't go. Like I'm thinking to Douglas Murray, you've never been 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 um 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 completely equivalent to a projection um on a surface which has no gravity and instead they behave more like um not necessarily condensed matter system but but more like other materials in extreme conditions but other things that we can have more control over. So that's one possibility we we can try to make traction into those dualities.

Um 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 universe. In fact, everything we are is the results of what happened at the very beginning of the universe and some of that um has implication 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 can't say I do that often but so ask yourself your that question is when you I know it gets cold when you get up there. It's very It's super cold.

It's super cold, but it had there is such a thing as a temperature of the sky. Um we can go into that if you want. Um 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 a 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 cool down, it relaxed a little bit.

It it became um 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 um 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 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 it reach 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 this soup of fundamental particles. So, we can look back in the sky to to many many years ago uh to a time where the universe I'm going to say something wrong, but I think was about 300,000 years old. Uh you can uh Google the the surface of uh 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' you say? Surface. The surface. The surface of last scattering. So that's the last Yeah. Last scattering.

Scattering. That's the last time photons got scattered. The surface of last scattering is the point in the early universe approximately 380,000 years after the big bang when photos became 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 as the faint microwave radiation permeating the universe. Okay.

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 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 a 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 100,000. And now if you remove this constant temperature from exactly uniform everywhere in the sky, you look at you see those tiny tiny fluctuations.

So when you you see that picture um if you if you Google cosmic microwave background would it be under here? Yeah. Yeah. for so for the third picture that one that one yeah so this is a picture taken by of the universe um that's why the that's these are the temp the temperature fluctuations this is how the 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 fact 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 just pop 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 uh prevent from that from happening and they got an imprint 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 uh mission that looked at the temperature of the sky. This is from plank. Before that there was W map and before that there was Kobe at the end of the last century I guess and Kobe made the first measurement of the temperature of the sky and those fluctuations.

And before we had that there were other possibilities out there like cosmic strings and other kind of models that could potentially have explained observation. And since the first satellite um measurements of the temperature of the sky, we now know that all of those alternatives are not correct. And in fact, it's 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.

That's right. That's right. How did we come up with when the photon escaped? Oh, so so this is related to the temperature of the of the universe. We we we we actually have a very good handle on how the universe has uh cooled down. has that how it has evolved.

In fact, the the biggest handle we have on the evolution of the universe is the concentration of various kind of elements being present. The so the 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 the it would be helium. Um, and then if you took two helium atoms and you put them together, they're gonna generate um, sorry, the first scratch. The most abundant one is the hydrogen atom. Okay.

You were happy with both. Yeah, we Yeah, we got to fire you now. It's misinformation. It's a hydrogen atom. And then you take two hydrogen atoms, they can make helium and you That's It makes your voice go up.

That's right. That's right. I was biting my tongue on that joke. I held that off for like a minute. Give me credit.

That's why and that's why you're like, "Oh no, I have to keep." Yeah. 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. Okay.

So we actually this is 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 I think this was back in 2023. I remember I think Brian Keading 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 familiar. So typ typically nowadays we say it's 13.8 billion something like that. That's exactly correct. I had that one right again.

Okay. So I don't I don't know. I should I should ask him what he had in mind. Um there's various type of um arguments about all sorts of things. Um now I'm trying to think what he was thinking about.

Yeah. Can we Google that Allesie? 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.

Yes. So yeah. 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 you're going to get very lonely because things are going to get very, very diluted as well. Yeah. All right. So we have this up here. Allessie 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 Rean Ra 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.

Oh yeah. Yeah. Yeah, I I uh 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 uh 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 it wouldn't change the math on solving for the 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 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 could be much more time there or far less time um at that point.

I we don't know far less time. Well, no, sorry. They they could what I mean is we we we set times error as a big bang and then we sort of set up the the clock from there. But precisely what happened during the first uh 10 to the minus uh 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 do you believe in a creator I believe in physics so I believe that something something must have happened no the the curious question is it's much more natural than nothing was there if you ask me what is what is uh 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 we have the chance to be somewhere and to ask ourselves those questions um 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 than that um 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 for everybody. We ask ourselves the same questions and we're actually very curious to understand where are we coming from and how it works and uh 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 have happened you know if you look at if you look directly at like Lawrence Grouse'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 it existed. It's like, okay, but we can't even picture what nothing looks like. That's right. 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 why that's why when you 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 Even the idea I mean, if you want to get real meta, even the idea of nothing is nothing. It's something.

It's something. Yeah. Something. It's [ __ ] crazy to me. But, you know, I I just don't know.

I I I think religions make a lot of assumptions on things. And so I I don't I don't personally ascribe to anything, but I'm open-minded on on, you know, whether or not there's things that have been passed down that we that 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 improbably 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 the 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 like you seem so happy golucky and like you love learning, you love working on your research, like have such good attitude about things. But if it did, if your research pointed to there really was no purpose, we're just a mathematical anomaly, like would that change your outlook? So I certainly don't think there's any purpose. There's no purpose of it of us being there. But that's why our purpose is for us to to understand why why we there.

Um I don't think we've been created because we have a purpose in in itself. I do I do think we're just a random anomaly. We know us as individual. We're just we're just an accident. And 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. But no one came down and designed you in in the outset. You could have you would have been slightly different if you Yeah, they messed up some things in the design.

I I got some complaints to put in. Okay, next time they'll try they'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 I'm trying to find our purpose.

So, how does that even work? No, I don't I don't think I've been I as a human or the earth or the galaxy or the universe has been created with a purpose. Uh 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. Uh I do I do personally think we are 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. They still did happen. There there's a lot of other things that could have happened and they haven't. There's lots of other things I can imagine that can in fact never happen. So the fact that like what? Well, there's other structures of reality where I know that they don't work.

I can come up with theories. They simply wouldn't work. Um the the things are in a particular way and they 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 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 a 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 stubbing my toe, right? But it's all on the same level of like those are ne negative things. One is just way more negative.

But like we 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. you even thinking it's a video game I I don't even think it has as much of as a purpose as a video game. It just it just happened and I want to think of it as a happy accident because we we are here but of of course there are things that that are not happy accident 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 in into existence. And that's sad for all of the other you haven't come in, but it doesn't mean that you were created just the way you are because there was a purpose in you. Maybe they were, but I I I I don't think so myself.

Yeah. You don't have science to prove that right now. No, I don't. That's right. I don't have science to prove that.

Uh but still in 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 they 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? How 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 question we can ask ourselves why we the earth got created with just the right condition for us to being able to ask ourselves that question. This is this becomes more of a philosophical question because 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 questions based on what we are experiencing and that's not all the possibilities. Did you up 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 as human was quite different. Um and different different cultures think differently in fact in in what our purpose is and how we in fact should help each other and what the role of um the societies are.

Some of them are much more rooted around a core and some of them are much more individual and and I think that is also affecting how we think of ourselves as a purpose. Is it the purpose as us as individual? Is it as a family? Is it as a society? is it as a whole civilization on earth that that has many different meanings. I agree. I 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 on the earth who still live off the map, you know, think of like the unconted 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, you know, us who are sitting here with our iPhones, you know, it's a crazy thing to think about. Yeah.

Yeah. Yeah. But you, so you grew up in Switzerland, right? Um, partly so some years. Yeah. Yeah.

Do do you want to go? Yeah. Yeah. The origin of my life. Yes, please. Um, I think it ties together.

Uh, I was born in Switzerland. Yeah. Uh, I grew up in Switzerland and we moved to Peru. To Ayakucho. To Peru.

To Peru. Wow. Um, Ayakucho. Do you know Ayakucho? Do you know? No clue. It's in the Andes.

It's quite high. Oh, I've seen that. My buddy Paul Rosley'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. Unbelievable place.

Yeah. Uh it's beautiful. Be beautiful. Um quite different. Then I lived in Lima.

I spent some time in Ikitas, which is by the Amazon. Was he there? Where was he? He was Well, where he is, it's I don't even know if there's a town where it is cuz 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 though that we started at? I haven't thought about it in a while. So maybe I typically the the biggest place.

It's not that. It's like it's on He's on the Mandre Deios River. And there's a town right there that's going to kill me. I forget. It's like a It's like I think it's like a saint name or something like that.

But either way. So you grew up What was the name of this again? The the That was Ikitas. Ius. Okay. Uh, and then I spent some years in Switzerland and then some years in Madagascar and that's Oh, you were in Madagascar too.

That's where I was till I was 18. Wow. And uh and then what's going on in Madagascar? Well, nowadays uh a lot I guess. Um at the time at the time is an amazing place. It has its own ecosystem.

Yeah, it um 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 world. Uh and even the people there um the the culture is very very different from from anywhere else in the in the world. So go and visit if you can. Yeah, I would love to nature has so many different um levels of diversity between places which are more like the jungle to places much more like deserts to um to places that are near near the sea. Uh it's a beautiful place.

What why were you going all these different places? What what did your parents do? Why not? Well, what what were your parents doing? So they were working they were working for um support for sustainable development in global south. Very cool. Yeah. So for it depended precisely what it was depended on the different countries. Um in Madagascar there was a lot about deforestation and u trying to work uh with farmers in getting more sustainable ways to uh grow rice for the rice culture in a way that has an impinge on deforestation.

Um yeah depending on different countries also a lot of work related to um to younger kids education and um working in a way that is sustainable for the younger kids to go to school. Um because the way things were set up in some of the uh more remote regions was in fact quite different. Um and everybody has to work. Everybody has to work in as part of um the village uh work. But that also means that education for younger kids is not some sometimes not as easy to access to um as we we used to.

Yeah. Like when you go to a you were a teenager in Madagascar. when you go to like a a remote place like that and you know your parents are working within the actual people who live there and everything like are you 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 were you just constantly independent homeschooled or were you going to international schools in those areas so it depended on on the different places um in Peru for most of the time I was in the local school um uh in Madagascar. There was a French school in Antana Revo in the capital. So when we were in the capital, we would go in in the French school when we were there.

Um I never was homeschooled, but some of my friends that that's what what they did. Okay. Um it depended a little bit on on the situation. In fact, it's, you know, we're used to a particular way of living, but it's not so hard to adapt to quite different ways and and things are you get by, right? I guess so. Yeah.

One way or another. Why physics then? Because based on like how you move around, you'd think you'd be into biology or something like that. No, that's true. But I think that that's true. I think I would have liked biology.

It was just too complicated for me. Biology was too complicated. 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 hand hang on to something that didn't make sense and was the same wherever I would be by Yeah.

more uniform because based on your moving everywhere. That's why that's why that's why. So by the time you were applying to university as a teenager, you knew you wanted to go towards physics. Yeah. 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. There's everything has its ups and downs, but no, it's it's we are so lucky to being able to to be there and just ask ourselves questions say what what happens if if this is like that and and we can go and talk with people that actually build experiments and and look for things. It's amazing.

Yes, it's 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 actually connected to reality and realizing yes they are these crazy ideas. Can you imagine these crazy ideas that of quantum mechanics and general relativity and and and evolution, all of those things that you think these are crazy ideas, but people came up with just sheer creativity with those ideas and then they can't test it. It's it's incredible. And expand upon it. Expand upon.

That's right. That's right. Push them further. That's Yeah. We we were talking a little bit ago and and outlined the whole like 1915 theory of relativity of general relativity that 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 but like where do we stand based on Einstein's original interpretations which is some of a lot of which has been disproven like what like what is what is the current accepted theory if you will. Yeah. In fact Einstein theory is still I would say the best game in town. is still um we do 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 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 theory 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 in every day uh 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 um it's a best tested theory. It works over 18 orders of magnitude. 18 or 18 orders of magnitude. 18 orders of magnitude. So I can test gravity on things which are uh as close as um two two very thin sheet of paper within a micro micro meter distance apart.

So 10 to the minus 6 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 that black holes exist and not only they exist but when they merge within one another they distort space time in just a way uh so that they are gravitational waves with a very specific spectrum that propagate 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 and that that is all completely consistent. We measure that and exactly in the way we would have anticipated according to understand the general activity. 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 effect. We would 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 the 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 that I can't define that. There's really some something which is really correct in the relativity. Whatever, however we want to go beyond it, we always need to make sure we understand how to recover it in in all of the observations that we have in all of the experiments that we have because we made not not me but we as a as human being we made some predictions and they turned out to be right.

So so things are really correct. Um, so, so this is the first thing. It it's really even much better tested than than anything else. We we think we we think we see the universe. We see 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 cuz like light, you know, light is something we can we can see. I guess gravity it's like cuz we can feel it but we don't know. Yeah. It's just there's a mathematical equation that forces us to the ground, 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 speed of it. We know the speed of it and we 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 it affects everything. And so even though we think that we as individual we don't interact too much with gravity other than being pulled towards the earth uh 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 um the theories that we have at at our disposal at the moment. And it is. It very much is.

One of one of the things Gio and I were talking about right before we got on camera was the concept of like gravity. How do you say geog? gravity pulling us down or or pulling us in and then dark energy. It was on the the anti-gravity topic trying to put two and two together. So, I mean, you're going to explain it. How about you start? Well, we were talking about dark energy and dark energy effectively being an aspect of anti-gravity.

So, if gravity is going one way, anti-gravity is pulling you the opposite way. Yes. So if if if we for for us for me um we we still have a very uh 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 um because of gravity. And so if things are going the opposite direction, we like to call it anti-gravity.

Um and so that 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 um according to Einstein the relativity gravity is is so much more than just this phenomenon as us being attracted to uh to the earth. That's just one realization of it. And in that case it seems like it's an attractive things and two masses always get closer together. they would attract each other.

But that's just one realization of it. Um, anything is has an effect to gravity because anything lives on the spacetime. Space time is everything. We live on 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 spaceime.

So is that what you're saying just having thinking of nothingness is something this is almost like that just you by thinking you affect space time and so can you imagine that you are bending you you're thinking so hard you're bending space time yeah the overthinkers out there we're giving you too much yeah we are we are bending everything you are and I can feel it and can you imagine No, no, you have to be quite sensitive to to to feel it. Um, but that means that the way gravity works is actually very subtle. We we are thinking our head about gravity being this attraction and then 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 you um there's this gravitational acceleration that yes we do NASA does do use that um to to use the gravitational fields of planets um to to accelerate uh probes to push them in in the um the edges of the solar system. So you're actually using gravity to do something which would have seemed counterintuitive. We do that technologically.

We do that for space exploration. And dark energy does that. It uses how gravity works. It just follow the rules of gravity. 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 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 in a way which is very counterintuitive to us and which have has for effect to make space being not only stretched but stretch at an accelerated rate but just playing fair with gravity. There are rumors, yes, that certain organizations, yes, 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, so you have to tell me what you mean by anti-gravity. They make 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 going to 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 on? Yes. So I'm sure it exists and and the only thing they done out of it is create remembers. They haven't used it for changing in the world.

Allegedly. Yeah. Allegedly. Yeah. Yeah.

Bring it on. I mean DARPA says they were talking to dolphins telepathically in 1992. Yes. 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, you know, but it's like, so does I rely on dolphin. Do you need to talk to dolphin to go through antic? I mean, I heard dolphins are smart as [ __ ] you know, like 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'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 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 gravity here with us. It could be.

So we don't 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 um 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 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. 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. uh it's a little bit too puffy and diluted to had had the chance to uh 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 uh they 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 on that spacetime. They are here. They and 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 leaving 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 yet we know we can't access directly through the standard channels of communications. Um, 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 I we have strong evidence that it is actually existing. Now you you basically the 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 you put out a paper on that.

Is that right? Um no that was way before. Yeah. Yeah. Yeah. But what Oh no you won an award in 2018.

Maybe that's it. Okay. So when when did you start working on this? Um so it's always like that. There was never a point when I thought okay I woke up in the morning and say I gonna be controversial today or maybe every day I say that and let me just come up with something out of the blue just because um so we always explore things and we always try things. Um when I started doing the research that I do I was looking into extradimensional space uh because why not there's the threedimensional space that we know of in here but why three why that I think that's one of the most fundamental question 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 dimension or 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 dimension 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 start.

It has to start like that. You have to think crazy. We always Yeah, that's fine. Um and so nowadays we actually have much better constraints on whether or not this is not pos whether or not this is possible because we um we have proved uh particle collisions at very high energy. And so if those extra dimensions were there, they have to be really small otherwise when you uh collide particles at very high energy with one another, they would have the opportunity to start uh communicating with gravity.

through gravity with extra dimensions and that we haven't observed. So 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. Oh, so the multiverse is slightly different, but maybe maybe in your mind it looks like the same, but in fact that's slightly different because um if you have extra dimension, our universe will be all of all of it.

and and you'll have this extra dimension out there as well is 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 um will be confined on a surface. So just imagine our un what we know of what 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 and so through gravity you can start probing the extra dimensions. So just imagine like you you have those animals that are living on the surface of water those uh what is it called? um like the things that like Yes. float along. 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 um 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 depth of the pond and fishes uh living in there and uh plants and which sometimes there's bubbles coming out of and all sorts of things.

And so to really understand what they 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 that what 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 going to 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 that.

Oh yeah. So what it could look like is you take um you take two particles and you collide them together and then they start deciding that they going to start sending energy into the extra dimension instead of staying into our surface. And so what it would look like is you send those two part 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 you know you can't 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 or the other explodes and the other has, you know, some bits still in place, that's also an action. But if they go together and then suddenly they both disappear. Yeah.

That's where I would say it 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. Oh, I got that right. Yeah.

Yeah, you got that 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 waves 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 what was the biggest push back in the scientific community to you? Yes. So when we when when we work on things uh people derive boundaries people people set the rules of the game and and then sometimes you you're good. You're good.

I'm good. Yeah. Well in often you when you work on those things you don't rederive everything from scratch because it took some people 10 20 50 years to derive some results. So sometimes you 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 um you may be happy with that and you you might as well just invest your time making progress from that starting point as as opposed to rediscovering the wheel every single day of your life. So when I started there was this boundaries there was this set zero that had been formulated if you want um 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. Uh a go a ghost is 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 it would be the whole structure of reality would be unstable. Yes. So it's something with negative energy and it's so if you have if you have something like with positive energy and something with negative energy they can just annulate each other. So, 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 thought that it would be impossible to think of a theory of massive gravity. We can go through what that means. But because if if the graviton had a mass, if gravity 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 uh correct proven mathematically in many different languages by many different people and those have been proven in different variation over a period of of 80 years.

And so when we started doing what we do 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 an alternative that would um help us make progress without being um 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 the surprise the big surprise is then we ended up having something which worked a little bit. It wasn't perfect. Um, 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 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 now it becomes in fact technical and and you go and you actually it goes through pen and paper and writers of equations try to understand where is this thing why we 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 they weren't as right as 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 in actually not a very difficult way.

That's got to be kind of scary though when you're when you're getting to I don't want to 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 unit's turned just a little bit to the left and it should be to the right it's that's got to be so strange I mean even myself I I remember I gave talks myself saying this is not possible we have all of this yeah all of these wellfounded uh 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 and then it works 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 well you say what I do wrong and then you say but why haven't I thought of that before it's so obvious on 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 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 so 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 is it almost becomes so second nature so trivial that you don't even think it's relevant anymore it's not 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 seems like quite the leap and I I never quite anticipated it would be quite such a h 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 where where is this all going? Yeah, it took 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's wrong and then it 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 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 con constantly confront yourself with the rest of the community and have sanity checks. Um sanity checks.

Sanity checks with yourself and with the math. No, no, there is a lot of that and you can um 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 it's not fun, but that's part of what you sign up for.

And you have to accept that. And and you have to accept that this is most likely going to 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 Keading 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 um 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. That's 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 some, they're like, [ __ ] Yeah. Yeah. Yeah.

Yeah. And the 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. Um 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 it's dust along the way. It's just um nature is not simple.

It's very difficult and 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 but you should still explore them. Yeah. Yeah. But the the concept of mass of gravity itself before you got to working on it and building upon it the the actual base had existed before right so people had a um explore whether that would be a possibility and it's a very natural one who had explored that and when uh so Einstein came up with Einstein's theory he didn't call it like that but with the theory of general relativity in 20 1915 and then quantum mechanics started In 1925, very quickly after that, there was uh going into quantum field theory.

So understanding even the fundamental forces of nature as being represented by um at the quantum level. And so already in 1939, FS and Powley contemplated the possibility that you could have some quantum fields. Um some of those quantum fields uh have specific properties that look like a graviton as in Einstein theory of relativity. uh but you can also consider them to have a mass and there's what is called the fiat power 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 gravitton is massless as in Einstein theory of general relativity or could it in principle have a mass the same thing is being explored for the photon and so if 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 zeboson and they are responsible for another kind of force which we call the weak force which you probably haven't heard of no because it's weak. Physics is simple, right? And 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 but if 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 an effect and beyond that it's really hard to get those particle to excited.

They don't want to get excited. They like to stay there and like bubbly things just just there. And like the photon who wants he can't stay he wants to move. That's right. That's right.

So now you want to ask yourself the same question for gravity. Uh 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. But 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. It's some specific characteristics. But then you want to think of it as having a mass and in the sense of that it's not that it's massive, it's big or anything like that. It's just that you doesn't want to be shaked 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 be they can become a point where the graviton is not going to want to move too far away.

And it's quite not quite like that but it's not going to go too too fast anymore. M and so you built on top of this. Yeah. So, so they started already the first um models were already from in 1939 by Fiat and Pali. Uh 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 70s 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 they 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 meantimes from the 70s to uh to the early 2000 the way we phrase things as in the in the physical community and the way we understood things from particle physics changed uh a little bit and so the way people were phrasing that problem uh 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 um the it was the first time where different groups observing supernova converge to a consistent story saying that as you look at supernova further and further away. So these are explosions of stars further and further away they all seem to converge to the fact that it going faster. 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 uh for several things first happening at the beginning of 2000.

There was all of those things 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 the 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 theory of general relativity to describe what happens on very large cosmological distances. Right? 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 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 on a um 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 into That's right. It would be an alternative in fact of of dark energy. Um 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 all of the particles they they are quantum fields and they can pop in and out of existence. They are quantum fluctuations in and in and out and and we see them everywhere in the labs. We see that in in in everyday life that there's those quantum fluctuations uh 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 they 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 when it did like stir controversy with you coming out I guess with like building upon this theory? What what was the nature of the push back? 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 it went to different stages. I remember um we gave a talk and and some people raised their hand and said, "Oh, but there's those serums there and so your theory is wrong." So just because they existed. That's right. Um 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 and I think some of the 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 but coming 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 um we can understand it doesn't match and we can change the perspective so that um 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 um it wasn't completely obvious to start with. Yeah.

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 for a lot of people because we we we in fact we learn 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 what where where are you building your intuition from? and set that aside and separate the different pieces and convince them that uh something is actually working in a different way. Were you able to convince some of the harsh critics? No. Yes. Yes. It it took it took five years.

Slow learners. Yeah. So I think it gained momentum as time went on. Um I think for 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 and so so where where is it I should see um where things don't match and and every time you go back to what we did and what they did and we have to set sort of set up a dictionary Um and within that community we may convince a subgroup of people and and not another subgroup of people and the same thing for another community and then slowly and slowly uh we could convince more and more people but that was for the problem that that had been identified from the beginning. Then after that people came up with all sorts of different actually what I had was saying at the beginning was something completely different and 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 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 in 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 going to solve everything. Uh so I I think slowly we could convince people that the first challenge was being um taken care of. There was a little bit of oh well hang hold 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 but doesn't mean that we're not making progress along the way and doesn't mean that we should just scrap the whole yeah uh so we learn what what's what's the next things you want to 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 um I don't I'm not wedded to to massive graity per se. I think it was fun for it was fun while for a while. I'm much more on the theory side and the reality is that that's more where my strength is and more where my expertise is.

Now it's getting more to the point where we need to um confront it with observations. We need to confront it with alternatives to to general activity. So we need to do numerical simulations. We need to compare with observation. look at black hole solutions, all sorts of things.

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

Uh, exactly. And I could do it. No problem. You can do Okay, we're counting on you. Okay.

So, now that that problem is solved, you can do it for massive gravity. That's right. Yeah. So, so that's good. That's all solved.

Um, 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.

Yeah. So the first exact solutions of this of two black hole 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 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 um how all your notion of space and time is evolving everywhere while you have this infinitely curved quantities in there. So you you have to take care of a lot of things. Oh yeah, it's it's complicated. It's complicated. It's a bit complic.

Yeah. Yeah. Don't worry. I'll write down. You're doing it right now.

Um and so in what needs to happen is the same thing for massive gravity. And and I I you can do it. I certainly can't do that. What 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 that's interesting. I think it can help.

It can speed things up. Um, 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 um non-trivial solutions for instance could it learn from how do I 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 what's the way I want to say this it could learn from data subsets that we have in the past to make conclusions that we haven't been been able to find ourselves so for that 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 uh find solutions in in different ways Okay. So, and we are doing that. This is this is something that that is a field of study. Um, 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 um something new if he hasn't actually got the chance to learn from it.

So it's like if 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 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. Um but I don't even know what it means to invent a new color for you. Yeah. It doesn't make you can't conceive it. You can't conceive it.

But in terms of it, 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 in some sense, we we we still need to have some of that guidance being there. And otherwise, it can't just pop in.

Yeah. Uh 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 sensient because sensient 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 I think it it it becoming more challenging because it really requires setting things outside the given parameters.

Yeah. And and that in fact we we are pretty good at that. We come up with a lot of creativity in this. But but AI is set up with some given uh variables. M um it doesn't mean that it can definitely within the framework in which we're working set up something which um we'll see something different as compared to our current paradigm.

It can definitely do that but we still need to set up some variables that that we come up with. Yeah, it's 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 midjourney was in 2023 versus what you can do with chat GBT 4.0 0 now straight away. Oh, it's insane, you know. So, that exponential curve, it's a it's a scary new world cuz it's 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, you know, economies and people's happiness? You know, it's it's a it's a really tough thing. But, you know, 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, you know, maybe. Maybe. Yeah. Depending where it goes.

Yeah. Yeah. Yeah. Yeah. Well, if it can solve all my problems, I wouldn't mind.

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, so I I do I do in in many different levels. I mean, you can you can think of it in different ways. Like we were talking to start with um even if you go in different places, the way you experience time is different. And so you can go somewhere and come back here and you have actually travel a thousand years in the future here. Uh but then you can't travel backwards.

Um but and that and that is scientific. You can you can think of this um you can think of things like uh again extra dimensions. You can think of uh being shortcuts uh through extra dimensions in any 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 in a in a universe. You're talking forward though with these examples.

It's always forward. Yeah. Yeah. um going backwards in time we you explore the possibility but it's it making it work without everything as we know it falling apart is impossible. So we can we can think of um situations where for instance you can have let's say light or you can have even uh gravitational waves um they travel at a speed 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 spacetime. And there's all sorts of funny effects that can kick in. uh 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 uh faster than light for a sufficient amount of time that I can then use that uh between different observers and having a situation where someone else would have the impression that it's going backwards in time. M 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 um does it work and this I guess is 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 19 44.

So I don't even know what it means to travel between different versions of the multiverse because the 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 that but the multiverse is different realizations of the universe but in between there's no spaceime 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. Yeah.

So, I don't even know what it means. Do you think that something like that could exist though? A multiverse? Yeah. Um, definitely. Yes. But I I I I think it's because there's no way for me to probe it.

I don't know whether that that's anything to do with reality. It's not connected anything to do with reality. It's not real. It's 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 in there and look at what happened and then come back. But I can't do it's 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.

Um but for 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. So it's kind of more of a catchall if maybe something goes wrong. Yeah.

So where it comes one way to think about it is to say if you're in string theory there's so many different possibility 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 happened to be in the one in one of them that is um 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 there aren't little human beings out there asking themselves that question. And that that's fine.

We we can 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 there's no way. 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 do 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 sparks if they were that would be great if they were because that gives you something tangible yeah to to test um so if you think I don't think but if you think um 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. Um, so maybe we'll be able to do that. Maybe I'll be there for the test. I want to test the multiverse.

May maybe the fact that you're thinking about it is it's just maybe that's going to bring it about. I don't know. That's why we're doing this podcast. Think about it hard enough. And that's right.

I'm going to Yeah. Yeah. transport into the middle of the table right here. But you you also I I I read you actually looked into becoming an astronaut yourself and and doing doing some things that are related to actually exploring like some of the science you've devoted your life to. So what why why didn't you I think at at some point like you got sick or something like that so you had to you had to drop out.

Yeah, I never got sick in the end. Um but I had indeed I had latent TB. Um 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 it's within you. Um, it's quite common.

Um, I don't know about the US, but throughout the world, it's it's really very common. A third of the world population has been infected at some point. Still like the case? Yeah. I mean, in some part of the world, TB is very very present still. M and so I've been living in different countries.

This it's probably perhaps not so surprising in uh in itself. But you went to actual it was it was in the European Space Program, right? Yeah. The European Space Agency. And so every they had actually in 199 uh no sorry 1920 or 192021 I don't remember 1920 21 they had an astronaut a new astronaut selection but the one I um applied to and I went through was in 2008 2009 so it was a long process of um call for astronaut um people apply and there's a whole year long more than a year-long selection program. And what does that look like? Uh so there's a lot of um psychological test and teamworking test and uh stress test.

Yeah. Um psychological test with different people trying to check really I think the main thing is you want to check are you going to be okay uh out there? Are you going to be okay out there? Not not just for a few minutes but potentially for months. Yeah. And sometimes in situation that may be quite stressful and are you going to be working with the others to make it uh make it okay or just they need people like not on clonopin or something. Yeah, that's why so somehow they thought I was okay with that respect.

Um and then there was um there's also some logic test and some in fact some physics test but but more some IQ test and a lot of um stress test putting different people in situation where it could be perceived a bit stressful and they have to communicate with one another to uh to get out of it. Uh it was fun in fact and uh as so eight more than 8,000 people applied. Um and as the process went through uh you could see that the people that were going down uh they were really nice people. They were really thinking you could be with them in a room for six months um with quite challenging condition and it'll be fine. You could really rely on them.

Um so they definitely did something right through the process because the in the end I was um with the last 42 and they did groups of people so with a group of seven people where we had very intense um medical test and that's where they found this and that's that's when they found it. Yeah. What did that feel like when when they told you? So throughout that week uh I went through all sorts of tests. You can imagine they do all sorts of of things. They really want to 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, uh, which are quite intrusive. So, the whole week was really, really intense. And by the end of the week, I had um a chat with the doctor in charge. We went through saw the results and he said, "Oh, everything looks really good." And it was the first time I thought, "Wow, maybe that can work out." And he was saying, "They actually need a woman and it will be good." So I thought, "Okay." He said, "We're just missing for one.

We're just missing one test. I'll send you the results as soon as I have it. It's a DP TB test." So I thought, "Oh, that's fine. Oh, good. That's fine.

I don't Have you seen me? I don't have TB. I'm not coughing. I'm fine. Uh so I left and it's not like I thought, okay, this is this is it. But thought maybe there's a chance for this to work out.

And then uh 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. Uh so yeah, it didn't feel great. It didn't feel great, but it was it was very clear. It wasn't something where I thought, "Oh, if I trained more, I could have done it.

If I've done anything differently, I could have done it." It's not like that. There's no failure or anything on your part. It's, you know, it did feel a little bit like a failure. But but but it's a health test. Like, what are you going to do? No, there's nothing you can do.

There's nothing you can do. In fact, I think if it had been something psychological, I'd think, "Oh, wow. I'm I'm not a very good person. I should have been nicer or whatever. You can always blame yourself.

And and of course you can blame yourself, but it's that's just the way it is. It's not it's not like I could really have done anything about it. So So you just have to uh to pick yourself up and um and in the end things things turn out quite differently as compared to what I would have expected. But but things are fun. I'm having fun every day.

Yeah. You're doing a lot of cool [ __ ] It's cool. Yeah. But do you still especially like with private organizations like you've already referred to today doing some space trips. Do you still dream of doing that? I think it's less for me.

I 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 what is worth what is not worth to but for me um I would have wanted to do it like that. Right. Not six minutes. Yeah.

I got you. Yeah. Yeah. Yeah. Yeah.

Maybe maybe we can get you up there for a month though. We'll find somebody. Okay. Do that. Do that.

Yeah. We'll work on it. I'll see who keeps sitting in this seat. Yeah. Yeah.

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? You know, we have intelligent life here. We have humankind and a lot of other biological species. Then we look in our own solar system and you know there's somewhere 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 is very very strong and you know if you ask me it's I'm like well it's got to be like 100%. But it's a whole separate question when you start talking about, you know, 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 is really high. But now when you account for the fact that they need to communicate with us, they need to be leaving within a time frame that makes it possible for them to communicate with us. It's 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 live being within the right amount of time and also in the right distance so that it can that can be possible. It 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 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. But for them to travel faster than the speed of light, I don't see how this is possible. My push back without any real, you know, 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 that's like, "Ah, speed of light.

We figured that [ __ ] out [ __ ] a thousand billion years ago." So it please prove us wrong. That would be amazing that and I think you can find you can you can do other things. You can find shortcuts. You can find other 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 we do understand very well how the whole universe has evolved and how it got to be the way it has. 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 that 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 will they would have a huge impact in our understanding of the structure of everything. Oh yeah. So, 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 speed of light to an amount which is actually useful.

Um, 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? Oh, be because being able to travel faster than speed of light, Yeah. even ever so slightly enables you to being able to travel backwards in time as well. You can you can start doing all sorts of different different things. And so it opens a whole new realm of possibilities and the ways we are thinking about uh the laws of quantum probabilities for instance and how they add up together and all sorts of things they rely on um they relies on some laws of physics and what I like to call unitarity.

They relies on some guiding principle that does require some guiding principle like like not being able to travel back in time. Theoretically though, this is no no absolutely what I'm about to say though. This is 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 the universe were actually some sort of created reality of a higher species. Yeah.

Where whereby they created the speed of light. So that's nothing to them. Y right. Then hypothetically if that were the species who were somehow then sucking down into this world that they created and like morphing in almost like what's up fam? Yeah. then it could be possible.

But it 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 that's that's right that's why but in that case I I might as well I'm just doodling in that in that case and we all all our scientific reality is just doodling because it it it would just mean that we're trying to find patterns but those patterns they're nothing to do with anything real. They 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 there's no logic to it and you may as well just disappear. On that note, my brain is 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 is so cool and 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 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. Yeah. And you go through your whole story with gravity and and everything there. But we're going to have to do this again at some point. That was fun.

That was fun. Let's do it in outer space and we can try. We're going to call up Jeff and make it happen. All right. I got him on speed dial.

Yeah, do that. All right. Thank you so much, Claudia. Thanks. 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.

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