Roger Penrose was born on August 8, 1931 in Colchester, in the county of Eses (United Kingdom). Known for his somewhat heterodox positions within the field of theoretical physics, he is Rouse Ball Professor (professor) at the Mathematical Institute of the University of Oxford and author of numerous popularization best-sellers, among which stand out “The small, the big and the human mind “,” The new mind of the emperor “and” Shadows of the mind “.
Roger Penrose is, along with fellow British Stephen Hawking, one of the most famous and at the same time most important theoretical physicists of our time. His works in the late 60s and early 70s on what happens inside black holes, the so-called singularities, marked the way forward at a time when these strange celestial bodies were considered the cumbersome fickleness of a theory. of difficult experimental confirmation. For thirty years, Penrose has been busy developing a tremendously abstract theory: the theory of twistors . All this is part of a deep personal interest in discovering a new formulation in physics that unites the world of the very small with that of the very large .
–Why, in your early years of study, did you choose mathematics as your profession of the future? Was it something like a passion of youth?
-It was actually a set of passions. My taste for doing mathematics most likely comes from my father, who was also a scientist, although he was practicing in the field of biology. He was researching human genetics but he loved mathematics: games, hobbies … anything that had a certain flavor of numbers.
–I imagine, then, that your father would be very happy to have a mathematical child in the family, right?
-Well not much. I was supposed to be a doctor. My parents were and they considered that of the three brothers I was the one destined to continue: I had to be the family doctor. When I was 16 years old, I went to see the school principal for guidance on what I could study. I liked chemistry, biology and mathematics. But he couldn’t study biology and mathematics; he had to choose. At the time, I didn’t want to lose sight of math, so when I got home I told my parents that I didn’t want to be a doctor. It was kind of a shock to them.
–But it is clear that in the end he convinced them.
-It already cost me, already. My father thought that it was not a subject for those who could do other things. If you can do math that’s fine, but if you can study other things, better. It was difficult to convince him that I could do math, and I did.
–In any case, at a certain point in your career you decide to make the great leap into physics and today you are described as one of the most profound theoretical physicists of our time. What caused this change in attitude?
-Everything happened when I went to Cambridge University. There I became interested in physics thanks to the influence of a few scientists: Paul Dirac, whose classes in quantum mechanics were wonderful; Hermann Bondi, a true expert in cosmology and general theory of relativity …
–But who really was his mentor was also the cosmologist Dennis Sciama …
-Certain. We became close friends. Sciama had a very broad interest in science and he persuaded me to pursue physics. So having done a doctorate in pure mathematics I started to do research in physics, especially in the field of quantum mechanics, which studies the behavior of atoms and subatomic particles, and in general relativity, which deals with the structure of the large-scale universe.
–Why precisely did you focus on these two complex areas?
-Because they are two of the four great theories of physics of this century. The other two are special relativity, whose objective is the study of objects that move at speeds close to that of light, and quantum field theory, which has special relativity and quantum mechanics as ingredients.
–You jumped to the forefront of theoretical physics by studying the formation of singularities in the universe. In fact, in 1965 he had already found the conditions for a mass to collapse forming a black hole. How could you explain what a singularity is?
-In essence, a singularity is a great catastrophe in the structure of space-time. Consider that a black hole forms because, essentially, a very massive star begins to collapse gravitationally and there is nothing to stop it. In the end, all matter is destroyed. And not only that, space-time itself also finds its end.
–Could we say that it is as if space-time is breaking up?
-That’s how it is.
–And is there no natural way to avoid it?
-Not. Astrophysicists have maintained for many years that this unique behavior was the result of some kind of artifice, that in the real world, collapsing matter could escape this tremendous fate. However, this is not the case. Stephen Hawking and I show in the most general way that spacetime singularities are inevitable in situations of gravitational collapse.
–Then it is shown that black holes really exist …
-Keep in mind that I’m talking about gravitational collapse. Now, you have to see if that kind of thing happens in the universe. A few years ago, the existence of black holes was the subject of debate and it was something that was not very clear. But today we cannot doubt its existence, since our astronomical observations show us very massive and invisible objects that absorb matter from their companion star. Due to this, the matter as it falls into the black hole releases energy, in the form of X-rays for example, and thanks to it we can realize what is happening.
–I remember that two great experts in general relativity like Hawking and the American Kip Thorne made a bet about whether or not the Cignus X-1 X-ray source was a black hole.
-Certain. Hawking said no and Thorne said yes. If Hawking won, Thorne paid him a one-year subscription to Penthouse magazine, and if Thorne won, Hawking paid him a four-year subscription to Private Eye. I don’t know how it all turned out …
–Recently a book of his, The small, the big and the human mind, has been published in Spanish, where he defends that our universe is open, that is, that its expansion will never stop. This is a theory that many other cosmologists also hold and give different explanations for it. What reasons do you have for affirming it?
-The truth is that my reasons are not very scientific and are difficult to explain to a general public. They have to do with my interest in finding a reformulation of physics.
–How?
-Physics today faces an important challenge. We have two great theories, quantum mechanics, which explains the behavior of nature at microscopic levels, and general relativity, which is a theory of gravitation and deals with large objects. However, there is no theory linking them, there is no satisfactory theory of quantum gravity.
–What is your path?
-My proposal involves complex numbers. It is the product of my mathematical training if you mean that. I have realized that they are beautiful numbers, that give a deep understanding of the workings of the world. In fact, physics seems to be based on complex numbers. Quantum mechanics, for example, is based on these numbers, and to describe the structure of space-time you also have to make use of their field. Imagine that we are in space and we look at the sky: we see it as a sphere. If we consider different people moving at high speeds in different directions and looking at the same sky, each observer will see it distorted with respect to the others. This phenomenon is known as stellar aberration. Well, there is a very elegant way to understand this through the field of complex numbers and infinity. It is the basic starting point in my theory of twistors, which aims to bridge the gap between quantum and general relativity.
–What consequences would the confirmation of his theory have on our models of the universe?
– If the general philosophy of twistors is true, that is, that complex numbers are not only under the skin of quantum mechanics but also under the structure of the space-time in which we live, then the universe must be open. As you can see, it is not a scientific reason to say, in the sense of being supported by observations; it is rather aesthetic. It responds to the philosophy that complex numbers are fundamental to physics.
–Similarly, it seems that, as he has made clear in his books The Emperor’s New Mind, an international best-seller, and Shadows of the Mind, we need this new physics to understand consciousness.
-That’s how it is. My research goes in this direction. In fact, my position is against artificial intelligence, that with today’s knowledge we can design machines that can think. I think intelligence cannot be simulated by algorithmic processes, that is, by a computer, in the sense that we use the term today, of course. There must be a distinct, non-algorithmic ingredient in the way consciousness works. Intelligence is not similar to a computer program.
–How did it derive from the study of singularities to that of consciousness?
-Actually, the problem of conscience is not something that occurred to me suddenly, like a flash that you have when shaving in the morning. The problem of conscience is something that worried me for a long time. I have the feeling that the new theory that unifies the physics of the very large with that of the very small will have a lot to say on the subject of consciousness. We need a new formulation of physics to understand it.
–As with many other physicists, it seems that his driving idea when proposing new theories is the beauty of mathematics …
-True, and it is a path that must be traveled with care. But don’t think I’m the only one. A good example is string theory, which is supposed to be behind electrons, protons, and quarks. It is also guided by mathematical considerations.
–What is the problem with mathematics that it is so difficult to appreciate its beauty?
-And that many of the mathematical beauties are not difficult to see. I suspect that the problem is in the way of teaching them. I believe that disseminating science helps to transmit that beauty. Scientists must be able to convey the excitement of scientific research.
–By the way, there is a detail that denotes his passion for mathematics. In the notes to the reader of his book in English Shadows of the Mind , he gives a formula for finding the references to the pages of his previous book, The Emperor’s New Mind.
-It’s true. In Vintage’s softcover edition, the page numbering differs from the hardcover edition. Since I was referring to the hardcover edition, I had to offer some clue so that the reader could find the references in the Vintage edition. It may seem like a joke but it is not if you want to find what I quote in my book.
–One last question. Is it true that a son of yours had a Spanish girlfriend a few years ago, Zaragoza to be exact?
-LOL. If true. I used to go to Zaragoza from time to time. But in the end it didn’t work out.
Miguel Angel Sabadell
This interview was published in February 2000, in number 225 of VERY Interesting.
