Tackling Sir Roger Penrose

When THE WEEK interviewed world-renowned mathematical physicist Sir Roger Penrose

roger-penrose-arvind-jain-archives [File] Sir Roger Penrose, Mathematical Physicist | Arvind Jain

There were three of us—two science reporters and I—on the one side, and Sir Roger Penrose on the other. We sat in the lobby of a Delhi hotel trying to interview the world-renowned mathematical physicist for THE WEEK and Malayala Manorama.

Penrose had come to Delhi to deliver a lecture under the auspices of Dr Ranjit Nair’s Centre for Science and Foundations of Philosophy. Nair, who had earlier got Stephen Hawking, Alan Heegar and several such sages, had graciously arranged our meeting in the lobby of the hotel where Sir Roger was lodged.

However, the man was proving difficult. He was friendly, well-meaning, had no airs, and wanted to talk to us. But he was talking only mathematics and physics—black holes, cosmic rays, time, space, Einstein, Newton, neutrons, universe, cosmos, alpha, beta, and all that was Greek and Latin to me. We would ask a simple question based on our reading of Fritjof Capra and some low-level nirvana gurus, and he would launch forth on relativity, special theory of relativity, big bang, big collapse, expansion of the universe, end of time and so on.

All of that was going over my head. My two colleagues, the veteran V. Jayadev and young Jacob Koshy, both more erudite than me, were getting a little of what he was saying, but they too seemed worried. Would anybody read this? The interview was going to be a disaster, we thought.

Suddenly I asked, “Sir Roger, do you talk only physics? Or...”

“No..... Mathematics, too...”

“Well, I mean, do you listen to music, do you play piano? Do you watch movies? Things like that...?”

“I do whatever my son likes. He is quite young.” Sir Roger snapped and turned back to the beginning of time. Obviously, he hadn’t liked the distraction.

I decided that I would thrust the dagger. “Really? What’s your son’s name?”

“Max. Maxwell...” and to the end of the universe.

That sounded odd. An Englishman giving his son a Scottish name? I decided I would turn the dagger. “But Sir Roger, Maxwell is a Scottish name. You are English. Why did you give him a Scottish name? Have you named him after the great physicist Maxwell?”

For a moment, Sir Roger brightened. He smiled. “Ah, that’s one reason. But there is something more. I named him after my stepfather.”

“Your stepfather? You mean.... Max....”

“Yes, Max Newman. After my father died, my mother married Max. He brought me up, and taught me mathematics.”

Good Lord! Here we were talking to the stepson of Max Newman. The close associate of Alan Turing.... the men who cracked the Nazi Code. (The movie on Alan Turing, The Imitation Game, was still light years away.)

“You mean Max Newman of Bletchley Park team?”

“Yes, but he was not exactly Bletchley Park. There was actually another team, too. They broke the codes....”

Anyway, Sir Roger melted. He left his black holes, cosmic rays, end of time, first matter, and all that. He began talking like the rest of us.

We spent nearly an hour like that—off the record. Then we told him of our interview. He called us to his room, served us tea, and we did the whole interview again—though on physics, but in plain English.

FROM OUR ARCHIVES: Before the Big Bang

Interview/Sir Roger Penrose, Mathematical Physicist

By R. Prasannan, V. Jayadev and Jacob P. Koshy

What happened before the Big Bang? Pioneering mathematical physicist Sir Roger Penrose, 75, came to India with his answer in early November and delivered it at Delhi’s Centre for Philosophy and Foundations of Science. “Sir Roger’s work, some four decades back, on the singularity theorems in the general theory of relativity, proved the existence of black holes,”said Prof. Ranjit Nair, director of the centre. “This was applied to the universe as a whole to prove the, existence of the Big Bang singularity by Stephen Hawking. It took half a century after Albert Einstein’s formulation of the general theory of relativity, which accounted for gravity as a warping of the space-time manifold, for a Penrose to make the first major advance.”

Excerpts from an exclusive interview with Penrose.

You have come up with a new theory about what happened before the Big Bang. Could you explain it?

The picture I am presenting involves universe going through cycles, but it is not one where the universe expands and then comes back again—a Big Bang and a Big Crunch and then all over again. No. This doesn’t work because of a fundamental physical law called the second law of thermodynamics.

Can you explain the second law of thermodynamics?

It means the universe is getting more and more random.... If I run that backwards..., the second law tells us that the universe gets less and less random [as we go back into past]. So the initial stage has to be extraordinarily special. Any theory of the Big Bang has to take this into account.... One of the most important pieces of evidence—so important that the Nobel Physics Prize this year was given for this—is the extraordinary agreement between the observation of the microwave background and the famous Planck curve, which Max Planck introduced to describe the thermal equilibrium of background radiation. So there is a very precise relationship between the frequency of radiation as observed and the intensity.... So what we are looking at is matter and radiation in thermal equilibrium.

Thermal equilibrium means maximum entropy. It means greatest possible randomness. So we seem to be looking back at the very special initial stage and finding randomness, when the second law says we should find something very special. People try to explain this by saying that the universe was small in those days. But this is not the explanation, because it could apply well if in the future you had a Big Crunch.

Then what is the explanation?

What you are looking at in the microwave background is radiation. You are not looking at that one thing which is special—gravity. You are looking at everything else and not gravity.... What was special about the initial stage was the gravitational degrees of freedom of the universe was not excited.

Can you make it a physical theory which explains this imbalance?

This is what my model is trying to do. Let me say two things. One has to do with the very early universe, and one has to do with the very late universe. In the very early universe, the temperature would go up and up and up, as you get closer to the Big Bang. This has the implication that the energy of individual particles is so great that its mass becomes irrelevant. So you might as well say that there is no mass; it is all radiation of some kind.

We certainly are not going to be able to know the details [of the origin of universe]. But could we know the general principles? It seems to be a possibility.

Radiation has an interesting property, that it is not sensitive to scale. The matrix of space-time, according to Einstein’s general theory of relativity, at each point has 10 components, 10 numbers. Nine of these numbers simply tell you where the light comes, how light propagates. The tenth component tells you the scale. Now mass-less radiation doesn’t notice the tenth component. It knows where the light cone [a surface in space-time, represented as a cone in three dimensions, comprising all the points from which a light signal would reach a given point at the apex simultaneously] is, and that is what is relevant. The scale become irrelevant.

Now let us talk about the remote future.... One thing that is important is the existence of cosmological constant. People refer to this as dark energy. I prefer the original term.... The only way that general relativity can be modified without changing the general principles of the theory is to introduce this constant. Einstein did introduce it in 1917, but he retracted saying this is not a good idea. I am saying it is a good idea because it seems to be there. The model I am prescribing would not work without it [laughs]. It is absolutely essential to this model that the universe undergoes this exponential expansion which is a feature of a possible cosmological constant.

What happens to the contents of the universe as it expands, without collapse?

Our expectation is lots of this will fall into black holes. We will have large black holes in the centre of galaxies and this will continue to increase in size. So substantial amount of matter will fall into the black holes. The rest of it will decay away, or so. It depends on whether we believe protons decay or so on.

Can you explain black holes?

According to Stephen Hawking—and I accept what he says here—black holes have a temperature, very low temperature. But eventually the universe will expand to a degree where the temperature of the universe will be lower than that of even these very big black holes in galactic centres. At this point these black holes will start to radiate. They will lose energy; they will lose mass. But eventually the black holes will evaporate and disappear. This is slightly conjectural; nobody really knows what will happen in the end. But they get smaller and smaller and they get hotter and hotter. As they do this, they radiate more and finally disappear. With a pop. Not a big explosion in cosmological scales but disappear, yes.

Ultimately it will all decay away into radiation. There are some assumptions involved in this. But this is the proposal.

So what will the remote future be?

The remote future will also be nothing but massless radiation. If you have this massless radiation in the early stage and in the very late stage, there is no way of building a clock for that. A clock requires something with a scale. To keep time, you need mass. If mass has disappeared, you can’t build a clock. In certain sense, the universe forgets the notion of time. So the nine components of the matrix, which tell you where the light cone is, are retained. But the tenth component becomes irrelevant to the structure of the universe. So I do not say the universe collapses and contracts. What I say is the very expanded stage of the universe becomes physically identical to a new Big Bang stage.

This has a number of implications. One of them is that we have a second law of thermodynamics in the form that we seem to have in our universe. This scaling-down of the infinite expansion automatically produces a stage in which the gravitational degrees of freedom are highly constrained.

That means you don’t believe in Big Crunch?

There is no Big Crunch. It continues to expand. You have little crunches in the sense of black holes. But they disappear. All the black holes go away. They swallow information.... People argue endlessly about what happens to the information in the formation of the black hole. Stephen Hawking originally argued that this is lost. This violates general principles of quantum mechanics. Many people objected and Hawking changed his mind. I think he was right at first. He shouldn’t have changed his mind. The information is lost and it does violate general principles of quantum mechanics. That is a good thing, not a bad thing.

Does that mean quantum mechanics is wrong?

Quantum mechanics needs improvement. This is one of the clues to the nature of this improvement. But that is a slightly separate story. The information is lost in black holes and that is what happens to the entropy....

You are trying to say that the present universe evolved from a previous one.

That is right. But the previous one did not collapse. It kept expanding; it had this exponential expansion, but then the universe became irrelevant. It is a hard idea to get across.

The present universe evolved from a previous one. But the previous one did not collapse. It kept expanding....

But in terms of time....

Time? There is no clock. The universe contains no concept of time. In the sense of a clock. It has a sense of the direction of time; it has a sense of the light cones. You know how light behaves. But you don’t have the scale. You don’t have big and small. Big and small are the same.

Do you think the human mind will be able to know the origin of the universe?

We certainly are not going to be able to know the details. But could we know the general principles? It seems to be a possibility.

Can’t we have a good quantum computer to unravel this?

Consciousness is not going to come about by computational activity.... To attribute understanding to an entity that has no consciousness, is not a correct use of terminology. To understand something requires being aware of it. To be aware of it means being conscious.... They [computers] can’t have consciousness because understanding is not a computational quality.... No matter how powerful computational computers get, they will not possess understanding.

Present-day physics is essentially computation.... Present-day physics is fundamentally incomplete, [because] quantum mechanics is incomplete. You raised the issue of a quantum computer. The notion of a quantum computer uses the notion of standard quantum mechanics. There is no claim that quantum computers could do anything non-computational. They might do some things faster than standard computers. But that is only faster. That is not different. We need a beyond-quantum computer.

Can you explain why quantum mechanics needs improvement?

Many physicists will say there is no need to improve quantum mechanics. I say that it definitely needs to be improved. I have some people to agree with me on this—Einstein, [Erwin] Schrodinger and in fact [Paul Adrien Maurice] Dirac also took the view though not so widely known. That quantum mechanics is incomplete or [is a] temporary provisional theory.

Some of the main reasons were put forward by Schrodinger himself when he argued that if his equation was right at all levels, then he could produce a cat which is alive and dead at the same time.

So there is a series of Big Bangs?

Yes. Each one is a new one. I am not saying it is cyclic. This has been raised, saying the end itself is the beginning; [that] it goes round and round.... The reason I am not saying that has to do with some consistency requirements.... You could face this in a very science-fiction way which is a bit like the problem you have with time travel—where you could go back and kill your great-grandfather... [laughs].

The oriental belief is that the universe is always there.

Yes. But I am only aware of it. What I am saying does not have those inputs. I am aware of similarities. I find it curious, interesting. But I would not make any comment.

What is the status of the search for Theory of Everything. Do you think a few equations might explain everything?

It is conceivable. But it depends on what one means. Usually the term refers to physics. Does that encompass other things like mentalities? The present pictures of the universe are not very close to such a thing.

So there can’t be the end of physics? Like the end of history?

Maybe we will do something stupid and kill ourselves. As far as physics is concerned, that may be a related question [laughs] because maybe we will annihilate ourselves before we come to some conclusion about that.... I am not saying it is impossible. It might be that there would be an understanding of the general principles. Not in detail.

Even string theory....

Not only ‘even’. It is not even a theory. It is a mixture. It has some nice features. The original idea of strings has an appeal. But what I do not like are the extra space dimensions which are a feature of string theory.

Could you put Einstein’s discovery in perspective, nearly 100 years after he propounded it?

I would say, special relativity didn’t really need Einstein. There were ideas before Einstein which were getting close to it. There are ideas after Einstein.... I am specifically referring to Mikhovsky. The idea of a four-dimensional space-time. It was really essential to make the theory more complete....

Present day physics is fundamentally incomplete, [because] quantum mechanics is incomplete.

Whereas general relativity, where you have curved space-time as an expression of gravitation, who knows, without Einstein we might not still know that theory. That was his contribution. His impact on physical thinking was tremendous. The impact on technology has been very slight. The only thing I know is GPS [laughs].

What would you predict to be the next big tech breakthrough?

If you are talking about physics, it is an improvement in quantum mechanics.

What about quantum mechanics and gravity?

It is relatively easier. But what I am saying is a little different from what most people say. What people often say is that we need a theory of quantum gravity which will get round the problems of singularities and things like this. That means applying standard quantum mechanics to general relativity or some other gravitational theory. Not changing quantum mechanics. That is very hard—to see observational tests of theories. This union of quantum mechanics and general relativity will be a much more even-handed marriage.

Do you believe that there is other life in the universe?

I don’t think it is very frequent. Especially other life on our galaxy. I would expect that it is out there somewhere.... I hope it is not too rare either. Life perhaps is out there, but intelligent life is probably very rare.

What is your concept of God?

I don’t consider myself to be a religious person in the sense that I don’t follow any religious beliefs. I don’t believe in a kind of conscious supreme being. There is this comment by Stephen Hawking about knowing the mind of God. I am sure he meant that metaphorically. But there is an implication there in that terminology, that there is a mind there. You can talk about God in a very abstract way, in the way Einstein used to say. But when you ask about a mind, it implies consciousness. To my thinking, a conscious entity is something conceivable to ‘be’. If you ask, do I believe that a mouse has consciousness, yes. But I have no idea what a mouse experiences. It is conceivable to be a mouse. But God I find inconceivable....

But if you ask me, if there is a deeper purpose in the universe, maybe there is something out there, which drives the whole thing. I am much happier with that sort of concept.

What are your other interests, apart from science?

My main hobby is [my] six-year-old son. He is quite fun. His name is Max. Maxwell.

That is a Scottish name. You are English.

Yes. The name came from two sources. One is the obvious one. The great physicist. [Laughs.] That is incidental. The main one is: when my father died, my mother, in her seventies, married an old friend of the family—Max Newman who was a mathematician. A good musician, too. He also did another thing, which I was not aware of at that time. He worked at Bletchley Park in the code-breaking unit during the war. He was responsible for the design of the machine which was involved in cracking, not the Enigma which is what people know of—but the other one which was the FISH code or the Lorentz code. Hitler used [it] to communicate with his generals.

Do you watch films? Indian films?

Ah, I watched a video recently of [Aparna Sen’s] 15 Park Avenue. It is a very moving story. I enjoy all sorts of movies. I like things that my son likes. So there is this recent film by Wallace and Gromit about a rabbit. It was extremely funny. 

The interview was originally published in The Week issue dated November 26, 2006