Ideas - Pursuing the Mysteries of Gravity with a Radical New Theory

Episode Date: September 12, 2024

Theoretical physicist Claudia de Rham has spent her life captivated by gravity. She has taken up flying airplanes, scuba diving and was even an astronaut candidate. Her book, The Beauty of Falling: A Life in Pursuit of Gravity, explores the mysteries of gravity and how it connects us to the universe.  

My name is Graham Isidor. I have a progressive eye disease called keratoconus. Unmaying I'm losing my vision has been hard, but explaining it to other people has been harder. Lately, I've been trying to talk about it. Short Sighted is an attempt to explain what vision loss feels like by exploring how it sounds. By sharing my story, we get into all the things you don't see

about hidden disabilities. Short Sighted, from CBC's Personally, available now. This is a CBC Podcast. Welcome to Ideas. I'm Nala Ayyad. That is the sound of gravity, at least in cartoons. Most of us have a less antagonistic relationship with gravity than Wile E. Coyote. It's a fundamental part of our lives. We may not be conscious of it most of the time, but we see it working everywhere.

Everything invisibly tethered to the Earth. Well, almost everything. I know this defies the law of gravity, but you see, I never studied law. Gravity is not just a constant in our lives. It's integral to the fabric of the universe. Gravity is the most universal phenomenon that exists. And it is this universality of gravity that pushed Einstein to understand that there must be something more fundamental about it.

it's time to understand that there must be something more fundamental about it. If gravity affects everything and everyone in exactly the same way, it can't be encoded in the objects themselves, in the masses themselves. It has to be encoded in something deeper than all of us, in something that we are all experiencing, which is space and time. Gravity also seems pretty straightforward. Every time we drop something, fall down or throw something into the air, we know what's going to happen. But gravity is full of mystery, weirdness and surprises. Discovering its secrets could be key to unraveling some of the deepest mysteries of the universe.

Claudia de Rom is one of the world's most influential physicists at the vanguard of new ways of thinking about gravity. She spent her life captivated by gravity and the purest possible experience of it. And if you want to understand gravity, really appreciate gravity, you need to try to extract yourself from all other forces of nature. You need to embrace gravity and let yourself go to it entirely. And that may be quite challenging to do here on Earth,

but if you imagine yourself, as we do, in outer space, maybe orbiting the Earth, then you can fall so freely that actually you don't feel anything at all, even though you are experiencing gravity. Claudia de Rome is a professor of theoretical physics at Imperial College London. Her new book is called The Beauty of Falling, A Life in Pursuit of Gravity.

In August 2024, Claudia de Rom gave a public lecture on her maverick theory of gravity at the Perimeter Institute for Theoretical Physics at Waterloo, Ontario. I interviewed her on stage following her talk. You've been chasing gravity throughout your entire life. And I wonder if you could talk a little bit of how you developed the fascination with gravity at such a young age. That's such an interesting question. And I don't know if it's something that I have developed or I have simply not lost. I think some of this passion, I really want to believe that it's in all of us from an early age. And I can

see that we're all fascinated to some level with that phenomenon. And it's about not giving it up. It's about keep playing with it. There's some element from a scientific level where we understand how universal it is. And it is so profound that to me, experiencing it is something you can't ever give up. But on a more human level, I think we are all teasing with gravity to some extent, The notion of challenging gravity and how we play with motion for gravity. I think you can see in the Olympics, for instance, almost every sports is a little bit of a teasing with gravity to some extent. But it is also, I think, this fascination for gravity and the scientific perspective is part of trying to be part of something bigger than us.

There's something quite fundamental about that, about gravity itself, about the structure of space-time, even though that's probably not the way I would have phrased it from an early age, but very much in trying to understand the whole of the universe around ourselves. One thing you've done since an early age is travel. You've lived in so many different countries. I'm curious, and stop me if this is overstating things, whether you think thinking about gravity and contemplating gravity has in some way kind of kept you grounded, both literally and metaphorically.

Absolutely. I think understanding how you're being part of this bigger structure was very important to me. If you have to move from one place to another, you want to attach yourself to something which is more profound. Understanding our whole surroundings, understanding nature around us, understanding the cosmos,

I think there was very much this notion that things change all the time and there's a level of chaos around us all the time. But the sky itself doesn't change. And there's some constants in nature that you can attach yourself to. If you can rely on science to keep you grounded, it's much more peaceful. And it was a way for me to make sense of everything around me. Now, falling is such a central part of your book.

It's part of the title. Yes. I'm wondering what it is that made it so compelling for you, this idea of contemplating the feeling of weightlessness. I think there's an element which is blissfulness in some level. You extract yourself from any other type of distraction. Everything else is a distraction. Falling in itself is actually very, very beautiful.

And we may not have this impression because of what happens after the fall itself. Right. Which, unfortunately, on Earth, we can't really evade. But in itself, that's not the fault of gravity. It's very much giving yourself completely to one of the most natural phenomenon. Perhaps I don't have a survival instinct, which is as strongly developed as other people's. Maybe I mind less just letting myself go and experimenting this. You went to great lengths to experience weightlessness. Can you talk about some of

the endeavors that you've undertaken besides falling? And hitting the ground, which I've done a lot. And that's part of it as well. One of the experiences that we can all do, which I loved, is simply swimming and actually experiencing some level of buoyancy in water. And I started scuba diving from a very, very young age. And it wasn't the sport in itself, it was very much the feeling, the feeling of being part of this environment and being able to contemplate it in complete peacefulness, really being completely part of it as opposed to observing it from an external point of view. It's the same thing with flying, actually. When I was a postdoc here a few years ago now, I started to learn to fly. And that's probably one of the most thrilling experiences you can imagine, is being part now of the sky. And of course,

there's lots of things to tackle and lots of, your brain is quite busy when you fly. But it is very much in letting yourself to those elements as well and playing with them to some extent. And all of these pieces, all these actions, were leading to a very dramatic moment in your life, which is when you were very close to being chosen as an astronaut. That's right, that's right. Yes, so it is very much this driver to experiencing things

and being part of other elements that pushed me also to wanting, like many, many other people, wanting to become an astronaut. For more than two decades, I had this constant dream that I would want to become an astronaut. And you came really close. And I came very close. 8,000 applicants to become an astronaut for the European Space Agency. You were one of the last 40. Can you

talk about what you had to prove? What is it that you had to do to get to that level? There's many different stages. I should say that the application process that was for the European Space Agency, it happens every 15, 20 years. So you can't try again. It was a once in a lifetime opportunity. So many people excited by the idea, many people try out. And so you go through various selection processes through some simpler, I would say, medical screening and different screening, which was computer-based. But then you had much more intense psychological and team bonding, sociological screening, which it's hard for me to even say what it is that they were after or not after. But what I can say is that as the process went along, we ended up with smaller and smaller

groups. And really, the connection with those people was very profound. You could imagine yourself being locked in a very small room with them, and it would be fine. You could be in an emergency situation and it would be fine. And throughout the latest steps of the process, it was a week-long medical screening. We were seven of us, really almost locked down in medical facilities

with all sorts of medical tests that you can imagine. It was pretty intense. We had to go through one test after another. And rather than feeling any sort of competitions with one another, there was very much this sense of bonding and we were in it together. It was a very fulfilling experience. A fulfilling experience, but also one that left you disappointed. Yeah, I guess falling. It was effectively a technicality that prevented you. It was something I couldn't have done anything for, I think that's fair to say. I went through all of those tests and the last day, the medical doctor in charge and I had a meeting going through all of the tests I had gone that week. And he said, oh, there's just one last test we haven't had the results for.

It's TB, tuberculosis. And I thought, OK, we can wait for that test if you want to. But surely I don't have TB. I'm not coughing. I'm fine, right, I think. And I had been tested against TB in the past. And it always came up negative. A new test had come along and it was much more sensitive and it turned out I was positive for it. I had latent TB, it turned out. So you've been infected in your past by TB,

so you have the antibodies for that. And that was it. That was really it. So yeah, it was a bit of a disappointment. I think that's fair to say. What was your biggest takeaway from going through that process? I think it's very much the persistence. It's very much about the journey and about all the things that you learn to go into it, knowing that it probably won't work out and you still do it anyways. And I think this is something in the scientific process, in the research that I do in my everyday life. We do research, we look at models, we explore ideas. Knowing very well they probably won't work, but that doesn't matter.

It is part of the endeavor. I think it is a very human quality in itself that we take the chances, we take risks in how we explore everything around us, and that's allowed us to be where we are and reach to that level. Otherwise, we would just be doing the things that we know we can do very well, but not going beyond that. In your book, you write that we are creatures of gravity. What does that mean? I think there is this connection, which I think is at every level with gravity. There's an element which gravity is this attractive phenomenon,

and we are the result, we are the fruits of those attractions. We are part of it in a way that we can never really escape, which I think it is part of this wanting to challenge it to some level, but at the same time, we know very well we'll never be able to escape gravity. It's there all along because it is part of space-time. It is part of the way we are thinking. It is part of everything that we are. Can we go to the beginning, the Big Bang,

and talk about where gravity begins in that moment? Is it exactly that moment? Did it come afterwards? Do we know? We don't know. Even when we reach those levels, the very notion of that moment, that moment in time, stops making sense because gravity itself is intertwined with the notion of space and time, and gravity stops making sense at the Big Bang. So the very notion of time itself may stop making sense. And if there's such a thing as before the Big Bang, I don't even know that I can necessarily formulate that question. Some of my colleagues think they can.

I don't know myself. I don't know. Where does space and time come from? And how they started to realize is one of the biggest mysteries there is. And a lot of research that is actually being done in here is driven precisely by those questions of how to even phrase the notion of space and time or the notion of gravity when the standard tools that we're using to describe them stop making sense. If gravity were any different tools that we're using to describe them stop making sense. If gravity were any different than what we know and experience on a daily basis,

even by the tiniest amount, how different would the universe be? In what way would it be different? So we do rely very much on this interplay between the strength of gravity, the behavior of gravity, and everything we're living in it. And we understand how we are where we are in terms of living in a cluster of galaxy that got just formed from having the right condition and having the right evolution of the universe throughout its billions of years of existence. And if gravity had been every so slightly different, all of this, the way the galaxies would have got formed, the clustering of dark matter would have been very, very different. We are very dependent on this very subtle effects on gravity. You say that it's essential to the integrity and the structure of the universe. But you also say that it's weaker as a force than other fundamental forces. How much weaker? And what does that mean? That's an excellent question. How much weaker? And

it's hard for us to think of gravity being weak when this is really what we're experiencing. Maybe to give you an example of how weak gravity is, you imagine we are actually experiencing the whole gravitational pull of the Earth. Can you imagine just how big the Earth is? And all of the mass of the Earth has a gravitational pull on us. Now, I can take a simple balloon and rub it in my hair and pulling out. What will have happened then is just a few electrons from my hair will have been transmitted to the balloon. And there'll be also, in addition to gravity pulling my hair down, And there will be also, in addition to gravity pulling my hair down, there will be this electrostatic phenomenon that pulls my hair up.

And it will win. Just a few electrons, just a few electrons that have been transferred between my hair and the balloon are sufficient to counteract the whole phenomenon of the Earth. This is incredible. And so we don't think of it like that in everyday life because we are very much grounded on the Earth. But in some level, the smallest level of other fundamental force

is much stronger than the gravitational force. It seems every time I read about gravity, there's no escaping Einstein. Is there a sense in which when you talk about gravity, all roads lead back to Einstein? There's a lot of things that we have, that humanity has discovered in the past century, which goes back to Einstein. But the reality is he came up with those ideas, not by himself out of the blue. Those were bubbling in at the time, and it's very much us as a community at the time,

at the time, and it's very much us, as a community at the time, being ready at the scientific level to come up with those ideas. So it was only possible because of the developments of other people, like Lorenz, like Minkowski, all of those notions were just on the edge of being developed so that Einstein could put them together and come up with Einstein's theory of general relativity. them together and come up with Einstein's theory of general relativity. It is not quite the case that Newton came up with a theory of gravity and that was wrong, and along came Einstein and rephrased it in a way which was correct. It's not quite like that. A lot of the concepts of even Newton, we're still using them today. There's a lot of beauty in Newton's description of gravity, which is used in Einstein. So it's not binary. It's not right or wrong.

It's very much into going deeper and deeper in our understanding of science. It's layer after layer. And it doesn't make a previous layer incorrect, per se. It's simply not the full description. But definitely Einstein's understanding of gravity is doing such a beautiful job at describing, I would say, everything that we understand about gravity, that there is an element of scientific truth in it

that we can't disconnect ourselves from and come up with something completely new. Isaac Newton wrote, just to your point, if I have seen further, it is by standing on the shoulders of giants. And your work and the work of Einstein and others who have worked in this field builds on Galileo, Newton, Einstein, of course, Stephen Hawking, and many others. But the process of how this work is done is very much shoulder to shoulder. Can you talk a little bit about

that process, what it takes to actually advance the science of gravity, how you come up with a new idea, and what the role of the rest of the community is in confirming or not confirming it? So I think it is true, it's very much an endeavor for the whole community. And you can think of it almost as a sea where we have the whole community and there's bubbling in and out some different ideas. And some of those ideas will ultimately make sense. Some of those ideas were proposed way before their time and the community itself wasn't ready to accept it

or to think of it in these ways. So sometimes some of those ideas are correct and have been present, but expressing it in a way that the whole scientific community can actually make sense of it and accept it and move forward from that, actually do something with it, is very important. I think there is this level of creativity. There's an art in itself where you need to draw a slightly different picture in slightly different colors, but you can't do that if the framework is not there to some extent. You're listening to my conversation with renowned physicist Claudia Duran,

recorded at the Perimeter Institute for Theoretical Physics in August 2024. She writes about her potentially revolutionary theory of gravity in The Beauty of Falling, A Life in Pursuit of Gravity. Ideas is a podcast and a broadcast heard on CBC Radio 1 in Canada, on U.S. Public Radio, across North America on Sirius XM, in Australia on ABC Radio National, and around the world at cbc.ca slash ideas. You can find us wherever you get your podcasts. I'm Nala Ayyad. Hey there, I'm David Common. If you're like me, there are things you love about living in the GTA and things that drive you absolutely crazy. Every day on This is Toronto, we connect you to what matters most about life in the GTA,

the news you got to know, and the conversations your friends will be talking about. Whether you listen on a run through your neighbourhood or while sitting in the parking lot that is the 401, check out This is Toronto wherever you get your podcasts. You don't have to know any of Newton's or Einstein's equations to have a physical understanding of gravity. Our bodies and minds are constantly in a dynamic relationship of push and pull and negotiation with gravity. Understanding the nature of gravity's workings is a whole other matter. Newton's equations and law of universal gravity remain indispensable three centuries after his death. But he couldn't have foreseen how Einstein would

radically deepen our conception of gravity with his theory of general relativity. Gravity is the most universal phenomenon that exists. And it is this universality of gravity that pushed Einstein to understand that there must be something more fundamental about it. If gravity affects everything and everyone in exactly the same way, it. If gravity affects everything and everyone in exactly the same way, it can't be encoded in the objects themselves, in the masses themselves. It has to be encoded in something deeper than all of us, in something that we are all experiencing, which is space and time. Nowadays, we understand, thanks to Einstein's theory of general relativity,

that for instance the earth curves the structure of space and time around itself, and we're all experiencing this curvature, and that's how we're experiencing the gravitational pull from the earth. Now the larger the mass, the larger the curvature, and the larger the gravitational pull. Now, throughout the universe, everything and everyone is connected to this space-time, and therefore experiencing this curvature of space-time and experiencing gravity. You can think of the fabric of space-time as a patchwork of events in space and time, and gravity is a thread connecting between them. And first, actually, I would say here on Earth, on the surface of the Earth, I think this experience is quite tangible, because at any single point, we may have the

impression that we're living in a flat patch. And for thousands of years, we thought that the earth was flat. But actually, when we connect different points along a journey, this is where the curvature, in this instance, of the surface of the earth emerges. And then when you connect points along a curved surface, along a straight line, those straight lines may look funny and curved from the outside, but that's actually just what a straight line looks like, adapting for the curvature of the reality in which we live in. Claudia de Rom, to help me wrap my head around the idea that gravity isn't simply the effect of the curvature of space, but that it's actually entwined with space and time. I like to think of gravity almost as the life of space and time. You can think of the space-time as almost like the bear painting that gives you the framework, but gravity is actually what brings it to life, what actually brings the colors to it. Something to think about gravity is that even though we are

experiencing it through the manifestation of the curvature of space-time, there's much more of an interplay there than just being something static. It's not just the mass gives rise to curvature and therefore we're experiencing it sitting on it. It's very much of a game between us living on our space-time, affecting the space-time ourselves, and then feeling the effect of that. So it is a two-way process. So is it fair to say that we don't so much live with gravity

as opposed to living in gravity? Is that a more accurate way of describing it? We are living in gravity, and we affect gravity as well. So it's very much of a collaboration with gravity, in gravity. We are embedded in that, and I think it's part of the creativity of gravity. One of the things that was predicted by general relativity was black holes, even though Einstein himself didn't believe that they actually existed.

What happens with gravity with the curvature of space-time in a black hole? Okay, so already when we go close to a black hole, the gravitational pull gets very, very intense to the point, as probably you know, as you get close enough to the horizon at a black hole, you can no longer escape. So you can try to run away from it as fast as you know, as you get close enough to the horizon of a black hole, you can no longer escape. So you can try to run away from it as fast as you can, but you wouldn't be able to escape it.

Now, as you enter the horizon of a black hole, first, the very notion of space and time, because they intermingle, they sort of interchange each other. So when you think of the notion of where is the center of a black hole, that even notion doesn't make sense because it's not a position in space, it's a position in time. In the sense that you can't avoid the flow of time as you enter the black hole, you can't avoid the flow which pull you towards the center of the black hole. As you do so, the curvature of the environment becomes higher and higher. And this, even though we can't go inside a black hole, we do think that the lows of unsanitary general relativity still make sense.

We have no reason to believe that actually would be violated as you enter the black hole. And the prediction of unsanitary general relativity do tell us that the curvature becomes larger and larger and larger as you reach the center of the black hole, up to the point where the curvature becomes so large that we can't make sense of gravity as described by Einstein's theory of general relativity anymore. To me, it's kind of remarkable to see that Einstein's theory of general relativity in a regime where we can trust it predicts that it will enter a regime where we can no longer trust it. So Einstein's theory of general relativity, to some extent, predicts its own failure. Which makes it very special indeed.

It makes it very special. And I think to me me this is really a huge quality for a theory. If you predict from the outset when it will break down, you know from the outset what to look for in new physics. You, of course, talk about beyond all of this, and say that the story of gravity goes beyond the curvature of space and time, and you talk about something called glite or g-lite. Can you just explain what that is? Ah, yes. Glite or g-lite, however you want. It's a made-up term, but I like it, because it draws very much the analogy between light and gravitational waves. And we're all

experiencing light. It is actually the manifestation of electromagnetic waves. Light are electromagnetic waves. The same phenomenon before gravity. Those are called gravitational waves, but actually, in analogy with light, we can call them glide. They are actually very similar to that. So we are all here sitting, emitting gravitational waves, is what you're saying? Your heart is emitting tiny, tiny gravitational waves, glide. We're not going to detect those. It's not that we don't have the instrument to detect them. It's that the amplitude of those is too weak to even be theoretically possible to detect them.

But yes, this is happening. We have our strong evidence now of glide. We have detected glide, not from your heart, I'm sorry, and not from us dancing with our partner, but we have detected glide emitted by much more massive objects. And we need to have much more massive objects to see, like two stars or two black holes. When they're accelerated very close to one another,

then they emit gravitational waves, they emit light with sufficient amplitude that they're accelerated very close to one another, then they emit gravitational waves, they emit light with sufficient amplitude that they're actually observable. And we have observed them. Not theoretical, they are reality. And they're not instantaneous, however. Like if a black hole were to form in space, it would take a long time for us to feel.

Yes, so the ones we have observed, they happened millions of years ago, and they've been traveling constantly through space at the speed of light until they reach us. Claudia de Rom suggests that gravity has a sense of humor, a mischievous way of confounding science's expectations about the nature of the universe. For instance, the expansion of the universe. Space has been stretching itself out at tremendous speed since the Big Bang. But if the stuff that comprises the cosmos was mostly matter,

what we planets and stars are made of, and the more mysterious dark matter, the gravitational pull of all that matter should lead the expansion of the universe to slow down. But over the past 25 years, cosmologists have actually seen exactly the opposite. What has been confirmed over the past 25 years is that the expansion of the universe is not slowing down, it's going faster and faster. The universe is expanding at an accelerated rate. One explanation that cosmologists considered is something called quantum vacuum energy, energy that fills the entire universe, even the biggest and emptiest cosmic voids. Perhaps that's what allowed the expansion of the universe to shrug off gravity.

Now, if we take Einstein's theory of general relativity and we include this quantum vacuum energy, the good news is that it does lead to an accelerated expansion of the universe. The bad news, because there's always a bad news, is that the expected rate of acceleration of the universe from this quantum vacuum energy is way too fast. And it's not just wrong by a factor 2,

a small computational error that you can sweep under the rug. Actually, the expected rate of acceleration of the universe, thanks to the quantum vacuum energy, is at least 28 orders of magnitude. This is the biggest discrepancy in the whole history of physics. It would mean that the space between you and the person sitting next to you would be stretching so fast that you would go faster than the speed of light and you wouldn't be able to see each other anymore. Again, I'm a theorist, but I think that's wrong. I don't think that's happening. And faced with the biggest discrepancy

in the whole history of humanity, I would say, the standard approach that you may hear of is simply to ignore the elephant in the room. This problem is so big that I'm simply not going to look at it. Maybe it's just going to go away. I'm just going to postulate for a reason or another that this whole hugeness of vacuum energy does not exist. I'm going to set it to zero for an unknown reason that future generations are going to tell me. to zero for an unknown reason that future generations are going to tell me. And instead, I'm going to postulate the existence of another, hey, hey, new kind of dark energy fluid. And that is the new driver for the cosmic acceleration of the universe. So that is one approach.

And now I'm going to go a bit crazy. I like to go directly at the core of this problem. I like to allow myself to consider this vacuum energy, which should be present, actually driving the acceleration expansion of the universe. Because it is there, it is naturally there. And so what I need to do is explain why this vacuum energy doesn't have as large an effect on the evolution of the universe as what I would have expected, according to Einstein's theory, of general relativity. And this led to Claudia's radical theory that gravity itself has mass. So in my theory, in a theory that you can consider, it would have mass. Einstein himself predicted gravitational waves. Let me call it glide. But if we think of them as analogy with light, we know that light is actually a quantum phenomenon deep down. It's

carried by particles which we call photons. Now by direct analogy with that, we can think of a light. We can also embed it within a quantum framework. And so if we do that with Einstein's theorem of relativity already, we would expect gravitational waves or light to also be carried by finite quanta of energy. And in that case, we call those gravitons. So gravitons are the particles living in gravitational waves. So in Einstein's theory of relativity, that fundamental particle is a massless particle, like the photon is. But people have been considered what the possibility

would be for having the photon itself being a massive particle. And so you can think of the same thing for gravity. You can consider what the observational consequences of a graviton mass would be. So this is the type of theory that we are considering. Yeah. I'm finding it hard to kind of get my head around how gravity can be the effect of curvature in space-time while also existing as a force and produce waves and be a particle that has mass. How is that possible?

There's many different manifestations of gravity, which I think makes it so powerful. But again, I think there is a life to it which sort of goes beyond this geometrical picture and is very much encoded in this dynamics of gravitational waves, but also in this dynamics of gravitons and tells you that at a more fundamental level, actually, there's nothing wrong with putting gravity

at the same footing as the other fundamental forces of nature. And so gravity is a force deep down, like the other forces of nature. Even if weaker is a force deep down, like the other forces of nature. Even if weaker. Much, much weaker, yeah. Another property of gravity, according to general relativity, is that it has an infinite reach. Claudia's theory proposes a different view of gravity that would be more closely aligned with the rate of expansion of the universe.

Could it be that gravity actually doesn't have an infinite reach and I don't need to take all of this vacuum energy into account? If gravity had a finite reach, I would only need to account for a small proportion of this vacuum energy leading to the accelerated rate expansion of the universe. But this possibility has always been completely refuted, not because it wasn't consistent with observations, quite the opposite. Quite the opposite. Considering a theory of gravity which have a finite reach would actually help us reconciliate our expectations with observations of the accelerated rate of expansion of the universe.

It was because it was impossible to make it work theoretically. It was plagued with discrepancies which didn't seem to make sense in themselves until these two gentlemen came along, Gregory Gabadazzi and Andrew Tolley. And then with them, we managed to engineer a new architecture for gravity, a new model which could, in some sense, displace all of these pathologies in the other models.

How is that possible? How is it possible that gravity is finite? Okay, so this is very much related to the notion of mass. So just to try to convince you that this is not completely crazy, which it may be, but that's okay, because I think we should explore things. There's a thin line between craziness and creativity sometimes the finiteness of a force it has happened for some of the fundamental forces of nature and so so for instance the have you heard of the weak force i have not you haven't heard of the weak force and and i wouldn't have expected because the weak force is actually weak and so we and so so we don't really experience it in our everyday life although it is extremely important

for the structure within the atoms it's related to radioactivity for instance but we don't experience it at the same level as we're experiencing electromagnetism. And so if you were limited in your ability to travel very far, that would limit your range of applicability. And this is actually what happens for the weak force. And we understand how that happens at the particle level, at the fundamental level. And so in this context, it is useful to think of it in the same way for gravity. When you think of what happens for gravity beyond the range of

gravity, I think this is where your question comes in of how can I make sense of gravity? If it is everything about space-time, how can I think of having it a finite range? And it's not that space-time itself stops making sense after the finite range of gravity. It's just that the gravitational interactions through the curvature of space-time are inhibited. Or even just more basically, the fact that it's an attractive force suggests that it is always attractive. So it is always attractive. It's about how attractive it is and how it continues being attractive if you bring them very far away from one another. In everything we think,

it's not so much about distance in space, it's encoding in space and time, and the notion of much more, much deeper than just space and time themselves. Let me go back to an idea you just raised a moment ago, this notion that this theory is crazy. I'm going to regret that now. But it's not obviously the word that I would use or you would use, but it does go contrary to much conventional scientific thinking. And I wonder just if you could speak to what it's like

to work so actively and persistently against the grain of scientific thinking. And I wonder just if you could speak to what it's like to work so actively and persistently against the grain of scientific convention. Challenging is probably the first word that comes to mind. So I think for me, but I think for every scientist like me, just being able to think of new ideas is just a gift in itself. I think it's really a privilege. And we very much know that sometimes those ideas will work out. Sometimes those ideas will be also understood and maybe they will be wrong for what or not applicable for what we wanted them to do. But maybe they still have some inner structure in them, some inner beauty in them, which is applicable for something else, which is often the case.

For me, going against what the standard consensus is was very much in trying to understand what you are developing not making sense in itself and how much it is about connecting that with the way people are thinking. And I can tell you, I mean, I work on models, which sometimes can be seen as being controversial, and it's not that we can just give away everything we know and just come up with something else out of the blue.

We really need to embrace everything that we know, understand it even beyond any of the limits, everything that we know, understand it even beyond any of the limits so that we can understand how precise any little tweak will be. And I should say, if anything I'll learn about all of those explorations is how precious general relativity is. I'm very well positioned in understanding all of the beauty of Einstein's theory of general relativity. And you really need to embrace that to being able to make the smaller little tweak to it. I guess, and maybe this is an unanswerable question, but I am interested in that moment

when you realize that maybe something that is taken as a given is so much not a given for you that it's actually worth giving up and pushing against the grain to come up with something new. Yeah, it took me really a long time because in coming up with those ideas,

we had some models, but then everything that was given, I had to some level just taking it for granted. And I was trying for years, in fact, to understand how it made sense with the common wiseness because it simply didn't match. And I never woke up in the morning and thought, oh, I'm just going to be controversial. That's not at all the way I was going about it.

It just wasn't working out. And for me, it was very much taken into, there must be something wrong that I'm doing. And I was keep going to it again and again and again for years. I was redoing the same thing, not understanding how it was connecting with what we knew from the common knowledge had to be true. Until in the end, it was simply there as a mathematical fact that some equation did not match out. And when you see that things don't match out, then you have to go deeper in that and understand the origin of that.

And I was sure that it was coming from me having made a mistake until I realized that the mistake is not necessarily always on your part. So take us to the moment, if you don't mind, when the puzzle all came together. The moment when you knew that your theory worked, at least to your satisfaction? Yes. So it was over summer years where different pieces of the puzzle came in. But I think there was one moment where my would-be husband at the time, and I would like to think we would still have been married even if this hadn't worked out.

I was working in that model with Gregory Gabarazzi, and it wasn't quite working out. And my Andrew Tolley was in a coffee shop in Geneva at the time, and I cycled to him, and I was very excited showing him what we were working on and what he wasn't working. And I was very excited showing him what we were working on and what he wasn't working. And he just waited there for a second. And he started thinking about a different way to think about it from extra dimension. And we started talking about that. And it was very much the realization that some of the beauty that is present in Einstein's theory of general relativity itself, when you think of it more from a higher dimensional perspective,

actually that structure is fundamental for thinking about a theory of gravity. It was that click there that made us realise there is actually some beauty in it that we can explore, that we can use those as fundamental bricks for what we want to do. And I was just about to leave, actually, to give a talk in Paris from Geneva,

so I was locked on the train, and then I started calculating all of those things, and by the time I got in Geneva, I actually had all of this to 20 order, and it was working out. It was for the first time. You put things together, and they just sort of magically work out.

I mean, it's pages and pages of calculations and it's very easy to make a mistake, but when things just cancel out beautifully and the result just match out, you know there must be something correct there. There must be something that is beyond you. What's that moment like? Oh, it was really exciting.

It doesn't happen very often, really. Yeah. So you really have to savor those moments. Yeah. Absolutely. Yeah. Did you keep those calculations? I think there must be somewhere. Yeah. Yeah. Throughout the book, you write about falling and also failing. And you make it clear that failing isn't failure, and that it's actually a natural part of the scientific process. Could you speak to just how much of what you've been doing, and science in general, it really is about daring to be wrong? I think that is present every day in my life, And I think in the life of all the researchers, particularly in theoretical physics, where we are exploring and we have to challenge some of

the ideas. We have to explore what happens if. And probably what will happen is that it won't work out. But you won't know that it won't work out until you try it. And it's not so much about understanding what the answer is. It's very much, I think, almost a way to organize your thought, a way to analyze all of this and give you a clearer picture on how to relate everything together. So from every failure, I think I make new connections. I learn a lot. I learn much more from all of those failures

than any moment where things actually worked out. So how much would you give credit to just an ability to be resilient and to pick up from a failure? How important is that? It's essential. It really is essential. And it's not necessarily pleasant, but if you know that it is essential, and if you know that this is part of the process, hopefully it's a bit easier. I think it's not only the failure in itself, it's also how you represent this failure with respect to others. because of those failures, you may have the impression that your position in the field or your ability to drive new results is not as important as someone else in the field. And I think it is very important to realize that we are making progress together. I think that can be very daunting, particularly if you start in the field and you have the impression that there's all of

those successes out there and you are the only one attempting and not necessarily succeeding at every step. So can we infer from that that you'd be at peace with the idea that your theory may sometime be proven wrong? It most likely will, and that's okay. That's okay. That's not why we go through it. A quick question about something you've made reference to a few times in your book is that despite the fact that there is an increasing number of women doing what you do and in very prominent positions and indeed at this very institution, at some stages in your career, you have found it difficult to show others that, yes, women could do what men can do.

Could you speak to how that affected the way you worked? I would say yes, but after quite a lot of level of resilience. And I think this threshold you have to go through is quite detrimental. I think there were many times throughout my career where it was simply too much. It's not resistance against women per se. It's this notion that there's one way to be a scientist. And if you are not following that more, then that's not the right way to being a scientist.

And I don't think anyone per se thinks like that. But it is a little bit of when you go through it and also when you have to go through day after day, finding the own motivation within yourself and finding it hard to get recognition from the outside. Recognition from the outside is very, very hard to gain for anyone at all. And so if you may not look completely the same as everybody else, sometimes it gets a little bit harder. And I do know that for myself, and I do know that for a lot of my colleagues. After a

while, you may also wonder why you need to keep doing that when it does take a lot of your energy to keep having this level of resilience. You write in your book that the majority of the scientific community was skeptical about your theory. What's it been like dealing with whatever challenges have been sent your way regarding the theory? So, yeah, that's interesting. In retrospect, I can say, well, I knew mathematically he was correct. I knew also all the arguments that were

thrown in my face, actually, hadn't necessarily been quite as thoroughly thought through than what I had gone through. So there was this level of scientific process that I could stand on and think, logically, I know this I can actually rely on. But you have to separate that from the human process in being in a room full of people that tell you, you are wrong. And you can stand up and say, well, actually, look at this. But it does require quite a lot of motivation there as well. I think in retrospect, I can say, yes, it made me stronger to some level.

And some of it, I think it is true, is necessary in the scientific process that we don't just take everything for granted. We can't do that. We have to go through some of those levels. But perhaps sometimes it could have been done. Maybe in a more positive way for everybody. Whether the model of gravity that we have explored will survive those tests, we don't know yet. Overall, whether our theory of massive gravity,

the theory of gravity with a finite range that we have explored, will be for future generations to tell. But for now, I just want to contemplate the fact that just here, just right now, in this room, there's gravitational waves reaching us all the time from the depth of the universe. And with them, they carry the most profound and remarkable messages. If we detect them, if we understand them, we may be able to understand if and how we connect with other objects located on the other side of the universe, some 10,000 million trillion kilometers away from us. Understanding those gravitational waves and the nature of gravity

will allow us to better understand whether infinitely small fluctuations from emptiness that fill the whole of the universe from here on earth to the middle of the cosmic voids lead to an evolution of the universe, help us understand the past of our universe, the present, and the fate of the universe, and everything living in it. Even if your theory is proven correct, is there a way for us to know what we don't know? How much do we still need to know? Oh, I think this is one of the beauties with Einstein's theory of general relativity, that we know for sure we don't know the theory that I've been working on.

We have nothing to say with what happens at the center of black holes, for instance, in a regime where gravity becomes so intense that we can't use the Einstein theory of generativity to describe it. So we are very lucky in that respect that we already know what we don't know. There may be cases where we actually don't know how little we know. The more we discover, the more we understand, we realize there's so much more to uncover. Sometimes you actually need to simply wait for experiment and observation to really show you what it is you thought you knew,

but actually you don't know. And so it is very important, all of this exploration of the real world, to confront it with what we have. But there will come a point where things become so intense and almost so abstract that it is indeed hard to understand how little we know. This has been your life's work and will continue to be your life's work. But for the rest of us who don't maybe understand the intricacies of what you're doing, work. But for the rest of us who don't maybe understand the intricacies of what you're doing, why does it matter? What is the big picture? I think the reality is that that's what makes us who we are. I can tell you it matters. Some of the things that were discovered 100 years ago,

some of the things that were discovered 20 years ago, they do matter because we are using them in our technologies. They do concretely matter for everyday life. But I don't think that's... We are bigger than that. That's not why we do it. We don't do it directly for the technological application of tomorrow or in 100 years. We do it because we have to keep searching. That's who we are as humans.

That's the beauty of what we do, how we do it. And so we are all driven to the most the beauty of what we do, how we do it. And so we are all driven to the most fundamental question of what is our origin? What is reality? And we need to keep exploring that. I think it will never stop. I hope you never stop. Thank you so much for taking my questions. Really appreciate it. Thank you. Claudia de Rom is a professor of theoretical physics at Imperial College London. Her new book is The Beauty of Falling, A Life in Pursuit of Gravity. Special thanks to Hilary Potts, Mike Brown, Mark Healy, Josh Dawes, and the Perimeter Institute for Theoretical Physics. This episode was produced

by Chris Wadzkow. Our technical producer is Danielle Duval. Our web producer is Lisa Ayuso. Senior producer, Nikola Lukšić. Greg Kelly is the Executive Producer of Ideas, and I'm Nala Ayyad.