How failure helps this theoretical physicist grasp the mysteries of gravity

Quirks and Quarks18:19A new book about gravity celebrates failing and falling

Theoretical physicist Claudia de Rham has made it her life mission to poke and prod at gravity's limits, whether it's by diving deep in the Indian Ocean, soaring over waterfalls in an airplane, going through a year of astronaut training, or through her work putting Einstein's general theory of relativity to the test.

In her new book, de Rham takes readers along on her adventures, as she explores our changing understanding of how gravity works, and tries to parse the many mysteries that still remain.

De Rham is a professor of theoretical physics at Imperial College London. She spoke with Quirks & Quarks host Bob McDonald about her new book, The Beauty of Falling: A life in pursuit of gravity. Here is part of their conversation.

What is it about gravity that first fascinated you?

I think for me, gravity is this phenomenon that you can never escape, but it's also very universal in how it affects everybody. So it doesn't matter who you are, it doesn't matter how you may seem insignificant or how powerful you are, you will be affected by gravity and you will affect gravity. 

What makes gravity such a difficult concept to understand scientifically?

So one of the aspects of gravity as discovered by Einstein himself, was that we can understand gravity through the curvature of space and time. This idea that gravity is universal and affects everything and everyone in the same way, went to show Einstein that it had to be deeper than just being a force between two masses, between two bodies. It has to be really encoded in something much deeper than any one of us.

Failure is also part of the scientific process. So rather than thinking of failure as an embarrassment, we should celebrate it.- Claudia de Rham

And so what it has to be encoded in, is in the very structure of space and time, intermingled with one another, and that makes it very profound very deep, but also quite hard and challenging to deal with. Because if you're reaching regions of space and time where the curvature is so high, understanding how to describe gravity there also tells you that you need to better understand the very foundations of space and time.

Early on in your book, you tie the concept of falling with the concept of failure. Why was that an important connection to make?

Failure is related to many different aspects, either to life itself, but also to gravity itself, which has a point of failure. And embracing this failure, that is describing failing or falling, is actually a positive thing. It's allowing us to understand where the description of gravity as we have it — Einstein's theory of general relativity — where that stops making sense and we need to uncover something deeper than that.

So there's this element of failure that falling has, which is essential and beautiful, and that failure is also part of the scientific process. So rather than thinking of failure as an embarrassment, we should celebrate it.

How did going through astronaut training and ultimately failing change your thoughts about gravity?

It definitely made me much more human. I think in terms of the research process, it makes you perhaps a little bit more resilient or a little bit more humble in accepting and embracing some of those failures. I have learned a lot in in trying for many, many years to become an astronaut.

And when you fail after that, it's never really pleasant, but it also allows you to start over again and realize how much there is to life, how much there is to science with your life and everything around you. So it is actually an experience I would relish forever. 

You also got into experiments with buoyancy in the ocean. Tell me about that.

For me this idea of floating and being in complete harmony with the fishes and all your surroundings in the ocean is just beautiful. When you scuba dive you can really control your vertical dimension as closely as you want with just your breath, and in doing so you're very much in harmony with everything around you. So of course you're not in free fall, but the feeling of freedom that you feel is just incredible. 

What are some of the misconceptions of gravity that you would like to clear up?

There are several. I guess one of them is, Newton was describing gravity as a force. And then along comes Einstein saying, well, gravity is not a force, it's actually described by the curvature of space, so really the curvature of space-time. And, and when I say that, people often think that that means gravity is not a force, there's no notion of force. It's unlike electromagnetism, for instance, or it's unlike the other forces of nature that that we know of. And actually, that's too short: that's too quick a statement.

Deep down, gravity is still a force and the detection of gravitational waves that we have had here on Earth in 2015, announced in 2016, is the proof that deep down, gravity is a force just like the other forces of nature. And in particular that means that we can also describe gravity at a quantum level like the other forces of nature. So we know, for instance, that light is nothing other than an electromagnetic wave. That is, light is quantum in nature. And actually the same thing should be true for gravity. 

What are you working on now?

One of the things I've been exploring recently is trying to see if we can use gravitational waves to have a better understanding of what makes our universe. And we know that our universe is made out of dark components, dark sectors. We call them dark energy and dark matter. And one of the areas of research I'm working through is understanding whether some of those dark elements in universe could affect how gravitation waves propagate as they propagate through the universe to reach us.

So we're really using gravitational waves to better see the universe, not through light, but through a new channel of communication. I call it "glight" in the book because, to me, gravitational wave sounds very technical, it is as if, instead of calling light "light," I would call it electromagnetic waves. Which is the correct scientific term, but we don't spend everyday life calling, "can you please turn out the electromagnetic waves, please?" You don't say that, and so why should we say that for gravitational waves? 

Q&A edited for length and clarity.