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Young scientist: interview with laureate of Moscow Government

19.06.2017

Moscow Government has presented awards to young scientists. An interview with one of the winners, MEPhI graduate, candidate of physico-mathematical sciences Sergey Koldobskiy tells where to find the antimatter, why to go into physics and what an anomalous effect of "PAMELA" is.

Where's the belt of antiprotons? What is interstellar space made of? With the help of which data from orbit is processed? Sergey Koldobskiy is 31, he is a graduate of MEPhI, candidate of physico-mathematical sciences and a specialist in cosmic rays. In 2009, he joined the project of "PAMELA". It is an international space experiment, whose main task is the measurement of the spectra of antiparticles in high-energy cosmic radiation.

— Sergey, tell us about the project for which you received the award.

 We received the award for the study of cosmic rays in the experiment "PAMELA". This is an international project, the leading research institutes are located in Italy and in Russia. I was not alone, but with colleagues Andrei Maiorov and Sasha Karelin. We were in search of cosmic rays. This are elementary particles and nuclei that come to Earth from various astrophysical sources, such as the Sun, distant stars, supernova explosions which occurred a long time ago... And we catch in orbit all this diversity of particles.

Why?

There are two applications. First, the fundamental science, i.e. the study will help to understand how the stars and interstellar space work, how these particles reach us. And secondly, our work has practical significance. In space there is radiation. And when we're going to send astronauts to the moon, Mars or the International space station, we need to assess the background radiation and to create equipment that can take it.

— But flights into space have existed for a long time. Have not these methods of assessment been developed long before your research?

 They existed. But our research has revealed new data that allow us to build more accurate models. Now we need to be safe and accurate to say that there won’t be some very energetic particles in this region of space, therefore, slightly reduce the security settings. Then the production of chips will be significantly cheaper.

— Let us talk a little more about the benefits of your work. Its description says that the findings will help in the study of such substances, as antimatter and dark matter. How?

 One of the achievements of our experiment is the discovery of the belt of trapped antiprotons. We found that around the Earth there is a small zone where the antiprotons are captured. This is just the antimatter. But, probably, the main result was the so-called anomalous effect of "PAMELA". When we talk about particles of cosmic radiation, the most important value we have to measure is the energy spectrum. Roughly speaking, this is how many particles and which energy arrives to us from different sources. What we have seen for some particles was markedly different from the existing models. In particular, the spectrum of positrons, antiparticles, which are born mainly in interstellar space, had to be falling, that is, the number of particles decreases with the amount of energy. But in reality, it falls to some value, and then again grows up. And one of the assumptions is that this increase is due to the decays of dark matter.

Satellite has for ten years passed on the information. It comes in the form of zeros and ones, so most of the work is programming and data analysis in application to physics.

— Can you explain what dark matter is? Everybody has heard about it, but few know what it is.

 All objects that we know of — me, you, the table at which we sit, our planet, distant stars, galaxies, black holes, is all composed of ordinary matter that we can measure. But on the energy balance of the Universe, it turns out that ordinary matter is somewhere around four percent. Everything else is what we don't know. And approximately 22 percent is something called dark matter. It has mass and, therefore, interacts with gravity. But most of this substance does not manifest itself, it is something unknown. Evidence for the existence of dark matter was discovered in the mid-twentieth century, when they began to follow the spiral galaxies. You probably have seen such beautiful pictures in the Internet: a luminous nucleus and spinning "sleeves" from it. So, when they have been long observed, it was found that considering the weight that we see, "sleeves" should be rotated rather slowly. But in reality, they moved somewhat 10-15 times faster. Conclusion: there is a certain huge mass that we do not see and that causes the galaxies to spin much faster than visible matter gathering in them.

— What equipment have you used in your research?

 Basic setting weighing approximately half a ton is located on the Russian satellite "Resource-DK1". The experimental apparatus consists of various detector systems. Some allow to measure the speed of particles, the other — their weight, the third — direction, and so on.

Sputnik transmitted information for ten years. We got it at the Research center for Earth operative monitoring in Otradnoe, and then we processed it by means of MEPhI equipment. The information comes in the form of zeros and ones, so most of the work is programming and data analysis as applied to physics. The volume is enormous: in the final stage, i.e. after drop-out of the information we had about 45 terabytes.

— Why did you decide to apply for the award?

 We knew about it for quite some time — two years. But we were never sure our application would look convincing, and by 2016, all defended their theses, did a great job in the experiment, published numerous articles. Plus we're all relatively young, so decided to participate.

And are there any conditions on what you can spend the award?

 As far as I know, no. This is not a grant that is issued for a certain examination, but an award. It was given as an encouragement for what we are here good physics.

— What areas of physics, in your opinion, are the most promising? Including from the point of view of funding.

In my perspective you can call any area. But it seems to me, nuclear physics is one of the first in this list. It will be a long time well funded, because nuclear energy is in this area. This is still a very promising source, much safer for the environment than, for example, coal or gas. Global warming has not been canceled, it is necessary to finish infinite heat the planet. Nuclear energy does not heat the atmosphere and is very clean – of course, in strict compliance with the relevant safety regulations.

Fusion energy is also promising. It is not easy to obtain: in fact, it is necessary to create a "little Sun". The most famous project of fusion reactor is the ITER in France. A large and very expensive international project, in which Russia participates as well. Interestingly, they are trying to build a fusion reactor on the principles developed by Soviet scientists, on the so-called tokamak.

And, of course, a promising search for new physics remains: further exploration of matter, including antimatter and dark matter. This is fundamental research, but they can be applied at any time. Those who discovered electricity in the nineteenth century, did not know that the life of all mankind will be tied to it. The creators of nuclear energy also have not expected that it will be used. The man who invented semiconductors, did not know that they are everywhere — in phones, in computers, in TVs, and so on. All this was fundamental science, which in some decades has changed the world. Such examples are very inspiring.

My dream sounds simple, but is complicated: I would like to open something new, important and interesting

— How did you came to physics?

 My parents also graduated from MEPhI, I think, to some extent, it also influenced my choice. Although they never insisted that I chose a particular direction, especially physics. I was also very impressed with our school teacher, his name was Sergey Mikhailov. He was able to enthusiastically tell us about the physics so that the formulas and numbers were alive.

Well, plus I've always had a technical mind, liked mathematics, physics and chemistry more than, for example, drawing.

— Didn’t you have any desire to go into something more lucrative but less interesting — conventionally, the oil and gas sector?

 Not yet. A lot depends on funding, of course. I was lucky, MEPhI, and our project enables to earn more or less normally. On the other hand, I know many scientists whose situation was worse and they had to leave to a more monetary sphere.

Some do not change, but go abroad. Someone for money, someone because of the support of one or another region of the state. Do you have no such plans?

I don't want to leave, but I am interested in working in international projects, meeting with foreign colleagues like while working on "PAMELA". I hope that in the future the situation will not change and the state will have the opportunity to support interesting projects.

In general, I wish there was no division between our and not our science. Knowledge should be shared. And it would be great if all the scientists worked together. But it is just a dream.

— Speaking of dreams. Share your professional dream and tell us which scholars you look up to.

 The dream sounds simple, but is complicated: I would like to open something new, important and interesting. As for benchmarks — I admire the leader of our group Arkady Galper. He feels very well physics, knows what to do, where to go, despite the fact that he is in science from 50-s of the last century. Arkady Moiseevich did a lot for modern physics of cosmic rays, in order to develop it in Russia and our scientists could make a meaningful contribution to the world of research.

Among physicists who lived in the recent past I especially like two ones. First — Carl Sagan, American astrophysicist and popularizer of science. I am very impressed by his humanistic views on science, how mankind should use the knowledge to treat the Earth and each other. The second — the Soviet scientist, Vitaly Ginzburg. He literally did physics. And he was good in different areas.

Of course, I'll be glad if I once get the Nobel prize. But it's not a priority for me. I guess I'm not very vain

— How do you feel about Stephen Hawking? He is probably the most famous among living physicists.

Undoubtedly, he is a big fellow. Of course, his story is very complicated. It seems to me that he is very much supported by work, he lives by his ideas.

—There is quite a large list of unsolved problems in physics. Does it bother you that something will never be discovered? To fight all your life and not get any result?

 This, of course, possible. And not only in physics. But it does not stop me and my colleagues. We've already discovered, for example the anomalous effect of "PAMELA" and a belt of antiprotons. In such moments you understand that all things are possible.

And when something does not work, it is important to look at what you do. Sometimes, scientists like miners, dig in one direction. Figuratively speaking, they have already digged to the Earth's core, and found nothing. Instead, you need to step back, look at the whole picture and try other options.

— What's next in the plans?

 We are planning to work another year or two on this study to look for new effects. And then I hope to participate in the project GAMMA-400. This experiment, with which it will be possible with great accuracy to measure the direction of arrival and energy of gammas. Gamma rays are, in fact, light. The study is closely related to the study of black holes. It is already known that in the center of our Galaxy there is a black hole, but not yet fully understand how it works. It's very interesting. Perhaps there is an unusual energy source, which in the future humankind will be able to use.

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