Tech UPTechnologyÁlvaro de Rújula:

Álvaro de Rújula:

If there is a scientific specialty that responds to the topic of strange dedication to profane eyes, it is that of theoretical physics. And the person who exercises it could be the typical affable and absent-minded sage. But Álvaro de Rújula seems rather cold, judging by his speech he remains with a certain Madrid slowness, and by how he saves smiles, using only the right ones to underline some of the many intelligent ironies with which he ends his sentences. Accustomed to looking far away (at distant galaxies), he often loses his very clear gaze through the windows of the Autonomous University of Madrid and only dares to talk about photography, one of his hobbies.

?He has just been appointed director of CERN’s Theoretical Physics division, the European Laboratory for Particle Physics in Geneva. What is your position?
-CERN is a research laboratory, that is, experiments are carried out in it, but in the Theoretical Physics division, more than experiments, what we do is think. This department is small, there are permanently only 10 theoretical physicists in a place where about 4,000 permanent people and 5,000 visitors work. We are few and we paint little.

What does a theoretical physicist do?
-Theoretical physicists interpret observations and create theories that explain them. For example, thanks to Kepler, who was an experimental physicist, we know how planets move, and thanks to Newton, a theoretical physicist, we know why planets move like this.

At CERN they are going to build a new particle accelerator, the LHC, which will allow us to better understand the structure of matter. What do you think of the economic participation of the United States in the project?
-It is secondary, because this is a laboratory paid for by 19 European countries. The contribution of the United States from the human point of view is very great; there are 600 Americans working there. They are going to contribute economically with about 500 million dollars, but, in short, distributed in the 10 years of construction of the LHC, they are quite little. The most important thing is that the Americans work at CERN and that top-notch scientists come. And it is not bad that they give us some money.

Do you think that all the efforts of CERN will be for the LHC and other projects will be relegated?
-As fundamental science receives a percentage of the Gross National Product of European countries, which, rather than increasing, decreases over time, when you have a large-scale project, such as the LHC, you have to sacrifice practically everything else. This means that in a period of 5 years we will have very few new projects and, what is more serious, that there will be a pause in the training of young people, since the mechanism that generates new scientists will stop. Those who do their thesis at that time will not have anything really cutting edge to do. In this area, if you don’t have fresh data, you are in a particularly bad situation.

When the LHC is finished, will it be useful for the work of theoretical physicists?
-Each time we manufacture a new machine we do not do it for sport; This device will have an energy 10 times higher than the previous ones, in order to study the intimate structure of the elements that make up matter up to a distance 10 times smaller than the previous one and will allow us to understand the origin of the universe up to ages 100 times greater. than the ones we now pretend to know. Whatever happens, the answer is yes, it is a step forward. Naturally, this does not satisfy us, because what we really want is to find something surprising that opens up new unexpected horizons, but that only happens from time to time.

Something surprising, like what?
-For example, something that tells us that we had not understood well what we thought we understood. The most important things that have happened in this century have been the theory of relativity and the laws of quantum mechanics, which have given us the idea that the world is much more interesting and very different than previously thought. That could continue to happen.

There are scientists who are studying how to reconcile the two theories. What do you think?
-This is one of the topics in which there is more activity at the moment and has to do with the so-called string theory, which has no experimental verification, but constitutes the most important hope of theoretical progress.

Would such an important leap be taken? When could it happen?
-Until I have given it I cannot assure you. We do research because we don’t have the answers and we don’t know when we will have them. Honestly, I can’t answer.

What are you currently researching?
-Now I’m with a couple of papers on antimatter in the universe. I have collaborated on the proposal for the artificial satellite AMS, which will be tested by NASA from the space shuttle this spring. We are going to take the satellite there to see how it works and, after the checkup, it will be launched, in the next millennium.

Where is this satellite going and what is it for?
-It is not going anywhere, it is a device to measure antimatter in cosmic rays and it does it by walking for two weeks through the space shuttle. If it works, it will get on the ALPHA space station and search for antimatter.

How much antimatter is there in the universe?
-Everything indicates that the universe contains mostly light; a billion times more photons or particles of light than atoms. So the universe is made up of some dust (so to speak), which are atoms, and gaseous, solid or liquid things; and apparently there is no amount of antimatter. The recipe would be: lots of light, a little matter, and no antimatter.

Well, nothing, nothing …
-The one that occurs in the collisions between particles of matter with particles of antimatter. In cosmic rays, which are mostly hydrogen nuclei striking the upper layers of the atmosphere, sometimes there are collisions that produce some antimatter, but it is secondary antimatter, not something that exists in the same way as stars or the planets. Matter and antimatter are very symmetrical things, like yourself and your image in the mirror. They are so symmetrical that it would seem plausible that there was as much matter as antimatter in the universe, although in different places, because if they were in the same they would annihilate each other. But it is not like that, something happened in a moment of evolution that made matter win over antimatter.

Do you study what happened?
-First I want to understand how things are, to what extent it is true that the rest of the universe is like our surroundings. We know that our galaxy and neighboring clusters of galaxies are made only of matter, but until recently we did not know if other galaxy clusters, very distant structures in the universe, could be half matter and half antimatter. This claim was possible until recently; we are now convinced that it is impossible. But that we are convinced does not mean that we are right …

In your research, do you come to consider philosophical or cosmological concepts?
-They are two different things. Cosmology today is a science, in it it is possible to be convinced of certainties and falsehoods, but philosophy is not a science.

I mean if physicists ask themselves philosophical questions.
-Physicists of a certain age are dedicated to being amateur philosophers, but that is more due to age, than to physics.

Don’t they have more connection with philosophy than other scientists?
-Hard science has evolved from philosophy; in fact physics was called natural philosophy in the seventeenth century, so historically there is a connection. But now philosophy and science are very different things and I do not think that a scientist asks himself more or less philosophical questions than an inhabitant of the jungle that this particular civilization has not reached.

How about the particle teleportation experiment they did in Innsbruck?
-It has no chilling consequence. It is a subject that has been known for a long time and that does not imply at all that anything can be teleported; I’m not going to be able to put myself on a radio that receives me and broadcasts me suddenly on the Moon. The feeling given by the headlines of some newspapers is false and counterproductive; it’s bad to even suggest it. The experiment is interesting, it means what it means and it has to do with a criticism that was made of quantum mechanics in the 1920s, and since then, 70 years ago, more and more important and precise experiments have been carried out, because not all quantum mechanics agrees with reality. The rest is pure charlatanism.

What interesting problems does theoretical physics currently have?
-There are three interesting questions at the moment, in my opinion. The first is what the universe consists of, since we do not know what the dark mass of the universe is. Another related question, perhaps even more mysterious, is whether or not the vacuum has a mass and if there is gravitational force in it. The third profound question for me is where the masses of the particles come from, why does each fundamental particle have a different mass, and what does the concrete value of that mass mean. So many of the fundamental problems have to do with the concept of mass, which we probably haven’t fully understood yet.

Amelia Die

This interview was published in March 1998, in number 202 of VERY Interesting.

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