"The whole sky should be in flying saucers, but there is nothing like this": an interview with astrophysicist Sergei Popov

About astrophysics

Why did you decide to study astrophysics?

Remembering myself at the age of 10-12, I understand that one way or another I would be engaged in fundamental science. Rather, the question was which one. Reading popular science books, I realized that astronomy is more interesting to me. And I immediately began to find out if it was possible to do it somewhere. Fortunately, there were astronomical circles, where I started going at the age of 13.

That is, at the age of 13 you realized that you want to be a scientist?

There was no formed desire. If I was then caught and asked what I want to become, then I would hardly have answered that a scientist. However, remembering my childhood, I think that only special events could lead me astray.

For example, before my hobby for astronomy, there was a period when I was engaged in breeding aquarium fish. And I clearly remember what I was thinking then: "I will enter the biology department, I will study fish and become an ichthyologist." So I think I would still choose something related to science.

Can you briefly and clearly explain what astrophysics is?

On the one hand, astrophysics is part of astronomy. On the other hand, it’s a part of physics. Physics is translated as "nature", respectively, literally astrophysics - "the science of the nature of stars", and more broadly - "the science of the nature of celestial bodies."

From the point of view of physics, we describe what happens in space, so astrophysics is physics applied to astronomical objects.

Why study it?

Good question. Of course, you cannot give a short answer to it, but three reasons can be distinguished.

First, as our experience shows, it would be nice to study everything. After all, any fundamental sciences have, if not direct, but practical use: there are discoveries that then suddenly come in handy. It's as if we went hunting, wandered around for a few days and shot a single deer. And that is great. After all, no one expected what would be like in a shooting range, when deer constantly jump out and all that remains is to shoot at them.

The second reason is the human mind. We are so arranged that we are interested in everything. Some part of people will always ask questions about how the world works. And today fundamental science provides the best answers to these questions.

And thirdly, modern science is an important social practice. Quite a large number of people receive very large amounts of complex knowledge and skills over time. And the presence of these people is very important for the development of society. So, in the 90s, a popular saying circulated in our country: the final decline is not when there are no people in the country who can write an article in Nature, but when there are no those who can read it.

What astrophysical discoveries are already being applied in practice?

The modern attitude control system is based on quasars. If they hadn't been discovered in the 1950s, we would now have less accurate navigation. Moreover, no one specifically looked for something that could make it more accurate - there was no such idea. Scientists were engaged in fundamental science and discovered everything that came to hand. In particular, such a useful thing.

The next generation of navigation systems for spacecraft in the solar system will be guided by pulsars. Again, this is a fundamental 1960s discovery that was initially considered completely useless.

Some algorithms for processing tomography (MRI) come from astrophysics. And the first X-ray detectors, which became the prototype of X-ray machines at airports, were developed to solve astrophysical problems.

And there are many more such examples. I just chose those where astrophysical discoveries have found direct practical application.

Why study the chemical composition of stars and planets?

As I said, first of all, I just wonder what they are made of. Imagine: acquaintances brought you to an exotic restaurant. Ordered a dish, you eat, you are delicious. The question arises: what is it made of? And although in such an institution it is often better not to know what the dish is made of, but you are still interested. Someone is interested in about a cutlet, and astrophysicists - about a star.

Secondly, everything is connected with everything. We are interested in how the Earth works, for example, because some of the most realistic catastrophic scenarios are not related to the fact that something falls on our heads or something happens to the Sun. They are connected to the Earth.

Rather, somewhere in Alaska, a volcano will jump out and everyone will die out, except the cockroaches. And I want to explore and predict such things. There is not enough geological research to understand this picture, since it is important how the Earth was formed. And for this you need to study the formation of the solar system and know what happened 3.5 billion years ago.

In the morning, after exercising, I read new scientific publications. A very interesting bunch of articles appeared in the journal Nature today that scientists discovered the planet of a close and very young star. This is fantastically important because it is nearby and can be explored well.

How planets are formed, how physics is arranged, and so on - we learn all this by observing other solar systems. And, roughly speaking, these studies help to understand when some volcano will jump out on our planet.

Can our planet leave its orbit? And what needs to be done for this?

Of course it can. You just need an external gravitational influence. However, our solar system is quite stable, as it is already old. There are uncertainties, but they are unlikely to somehow affect the Earth.

For example, the orbit of Mercury is slightly elongated and strongly feels the influence of other bodies. We cannot say that in the next six billion years Mercury will remain in its orbit or will be thrown out by the joint influence of Venus, Earth and Jupiter.

And for other planets, everything is pretty stable, but there is a negligible probability that, for example, something will fly into the solar system. There are few large objects, but if they fly in, they will shift the planetary orbit. To reassure people, I must say that this is very unlikely. During the entire existence of the solar system, this has never happened.

And what happens to the planet in this case?

Nothing happens to the planet itself. If it moves away from the Sun because of this, which happens more often, it receives less energy, and as a result, climatic changes begin on it (if there was any climate on it at all). But if there was no climate, as on Mercury, then the planet will simply fly away, and its surface will gradually cool down.

If our galaxy collides with another, will it change something for us?

The very short answer is no.

It happens very slowly and sadly. For example, over time we will merge with the Andromeda nebula. Let's fast forward a few billion years. Andromeda is already closer and begins to cling to our galaxy at the edge. A person will be quietly born, unlearned at school, go to university, teach at it, die - and nothing will change much during this time.

Stars are very rarely scattered, so when galaxies merge, they do not collide. It's like walking through the desert, where scattered bushes are scattered. If we merge them with another desert, there will be twice as many stunted bushes. Although this will not save you from anything, because the desert will not turn into a wonderful garden.

In this sense, the pattern of the starry sky will change slightly over a long time. It changes anyway, because the stars move relative to each other. But if we merge with the Andromeda nebula, then there will be twice as many of them.

So nothing happens in a collision of galaxies from the point of view of people living on any planet. We can be compared to mold or bacteria living in the trunk of a car. You can sell this car, it can be stolen from you, you can change the engine. But for this mold, nothing changes in the trunk. You need to get right to it with a spray bottle, and only then something will happen.

The Big Bang happened billions of years ago. How did scientists learn to look into the past and find out how everything was there?

The space is quite transparent, so we can just see far away. We are observing galaxies of almost the very first generation. And now telescopes are being built that should see that very first generation. The Universe is empty enough, and out of 13.7 billion years of evolution, 11-12 billion years are already available to us.

This is another addition to the question of why study the chemical composition of stars. Then, to know what happened in the first minute after the Big Bang.

We have fairly straightforward data - up to the first tens of seconds of the existence of the life of the Universe. We describe not 90% or 99, but 99% and many nines after the decimal point. And it remains for us to extrapolate back.

There were also many important processes that took place in the very early universe. And we can measure their results. For example, the first chemical elements were formed then, and we can measure the abundance of chemical elements today.

Where is the border of space?

The answer is very simple: we don't know. You can go into details and ask what you mean by this, but the answer will still remain the same. Our Universe is certainly larger than the part that is available to us for observation.

You can imagine it as an infinite or closed manifold, but stupid questions arise: what is outside this manifold? This often happens in the absence of observation and experimentation: the field of activity becomes completely speculative, so it is much more difficult to verify hypotheses here.

About black holes

What are the black holes and why do they appear in all galaxies?

In astrophysics, we know two main types of black holes: supermassive black holes at the centers of galaxies and black holes of stellar masses. There is a big difference between the two.

Black holes of stellar masses arise in the late stages of stellar evolution, when their nuclei, having exhausted their nuclear fuel, collapse. This collapse is not stopped by anything, and a black hole with a mass equal to 3, 4, 5 or 25 times the mass of the Sun is formed. There are many such black holes - there should be about 100 million of them in our Galaxy.

And in large galaxies in the center, we observe supermassive black holes. Their mass can be very different. In lighter galaxies, the mass of black holes can have thousands of solar masses, and in larger galaxies, tens of billions. That is, a black hole weighs like a small galaxy, but at the same time is located in the center of very large galaxies.

These black holes have a slightly different history of origin. There are several ways how you can first create a black hole, which then falls into the center of the galaxy and begins to grow. It grows simply by absorbing the substance.

Plus black holes can merge with each other. So, we have a black hole in the center of the Galaxy and there is a black hole in the center of Andromeda. Galaxies will merge - and after millions or billions of years black holes will merge as well.

Do black holes have some function, or are they just a by-product?

The concept of modern natural science is not inherent in teleology. The doctrine considers that everything in nature is arranged expediently and that a predetermined goal is realized in any development. … Nothing exists just because it has some function.

As a last resort, you can still talk about symbiotic living systems. For example, there are birds that brush the teeth of crocodiles. If all the crocodiles die out, these birds will also die out. Or evolve into something completely different.

But in the world of inanimate nature, everything exists because it exists. Everything is, if you will, a by-product of a random process. In this sense, black holes have no function. Or we don't know about her at all. This is theoretically possible, but there is a feeling that if all black holes are removed from the entire Universe, then nothing will change.

About other civilizations and flights to Mars

After the Big Bang, a large number of other planets and galaxies were born. It turns out that there is a possibility that life also originated somewhere. If it exists, how far could it have developed to this day?

On the one hand, we will talk about Drake's formula, on the other, about the Fermi paradox The Fermi paradox is the absence of visible traces of the activities of alien civilizations that should have settled throughout the Universe over billions of years of its development. …

Drake's formula shows the prevalence of the number of extraterrestrial civilizations in the Galaxy with which we have a chance to come into contact. Take our Galaxy: the coefficients and factors in Drake's formula can be divided into three main groups.

The first group is astronomical. How many stars in the Galaxy are similar to the Sun, how many planets these stars have on average, how many planets similar to the Earth. And we already more or less know these figures.

For example, we know how many stars are similar to the Sun - there are many, very many. Or how often there are terrestrial planets - very often. This is fine.

The second group is biological. We have a planet about the same chemical composition as Earth, and about the same distance from a star that looks like the Sun. What is the likelihood that life will appear there? Here we do not know anything: neither from the point of view of theory, nor from the point of view of observations. But we hope to learn a lot literally within the next 10 years, to be a great optimist, and 20-30 years if we are more careful.

During this time, we will learn how to analyze the composition of the atmospheres of planets similar to Earth and other stars. Accordingly, we will be able to detect substances that we can associate with the existence of life.

Roughly speaking, terrestrial life is based on water and carbon. It is almost certainly the most common form of life. But in small details, it may differ. If aliens arrive, it's not a fact that we can eat each other. But, most likely, they drink water and, accordingly, their form of life is carbon. However, we do not know for sure and hope to find out soon.

My opinion, which is almost not based on anything, is that, most likely, biological life occurs frequently.

But why then do we not see this other life?

We now turn to the third part of Drake's formula. How often does this life become intelligent and technological. And how long this technological life lives. We don't know anything about this at all.

Probably, many biologists will tell you that if biological life arose, then reason is at hand, because there is enough time for evolution. Not a fact, but you can believe it.

And when Drake came up with his formula, people were quite surprised. After all, it seems that there is nothing unusual in our life, which means that there should be a lot of life in the Universe. Our Sun is only 4.5 billion years old, and the Galaxy is 11-12 billion years old. This means that there are stars that are much older than us.

There must be many planets in the Galaxy that are a thousand, ten, one hundred, million, billion and five billion years older than us. It would seem that the whole sky should be in flying saucers, but there is nothing like this - this is called the Fermi paradox. And this is amazing.

To explain the absence of another life, it is necessary to greatly reduce some coefficient in Drake's formula, but we do not know which one.

And then everything depends on your optimism. The most pessimistic variant is the lifetime of a technical civilization. Pessimists believe that such civilizations, for some reason, do not live long. 40 years ago, we rather thought that a global war was taking place. A little later, they began to lean towards a global environmental disaster.

That is, people simply do not have time to fly to other planets or evolve enough to do this?

This is a pessimistic option. Not to say that I believe in him, but I do not have any priority version. Perhaps the mind rarely arises after all. Or life appears in the form of bacteria, but does not develop even 10 billion years before the emergence of creatures capable of conquering outer space.

Imagine that there are many intelligent octopuses or dolphins, but they do not have handles, and they obviously will not make any powerful radars. Perhaps it is not at all necessary that intelligent life should lead to the invention of starships or even television.

How do you feel about the idea of colonizing Mars? And is there a hypothetical benefit from this?

I do not know why it is necessary to colonize Mars, and therefore I am more negative. Of course, we are interested in exploring this planet, but it certainly doesn't take many people. Most likely, they are not needed for this at all, because you can explore Mars using a variety of instruments. It is easier and cheaper to use giant humanoid robots.

However, there is an argument in favor of the exploration of Mars - terribly indirect, but to which I really have nothing to object. Roughly speaking, it sounds like this: humanity in developed countries is so fed up that a mega-idea is needed in order to shake it up and excite it. And the creation of a fairly large settlement on Mars can become a driver for scientific and technological development. And without this, people will continue to change smartphones, put new toys on their phones and wait for the release of a new set-top box to the TV.

That is, the flight of people to Mars is about the same as the flight to the moon in 1969?

Of course. The flight to the moon was the American response to Soviet successes. He certainly shook up this area of science and gave a very big impetus to development. But after completing the task, everything came to naught. Perhaps Mars will have about the same story.

About myths

What myths around astrophysics annoy you the most?

I am not annoyed by any myths around astrophysics: I have a Buddhist approach. To begin with, you understand that there are a huge number of idiots among people who do stupid things and believe in nonsense. And all you have to do is ban them on your social networks.

But there are also more serious areas. For example, myths in socio-political matters or in medicine - and they can be more annoying.

As I remember now, March 17, the last day when the university worked. I thought to quickly go to the therapist in the clinic, ask about some nonsense. I am sitting in an office, and then a nurse takes a person to a doctor with the words: "A young man came to you here, he has a temperature of 39 ° C."

The beginning of the epidemic, a person is a student at Moscow State University. And he got up with such a temperature and went to the clinic. And the nurse, instead of packing him in a plastic bag, took him through the line to the therapist.

And that worries me. But the fact that people think that the Earth is flat and that the Americans have not been to the Moon worries me in the second place.

Can you, as an astrophysicist, explain why astrology does not work?

When astrology appeared a thousand years ago, it was quite a legal and reasonable hypothesis. People saw patterns in the world around them and tried to understand them. This desire was so strong that they began to think out - it's just that our brain is so arranged that we order the world around.

But time passed, normal science appeared and such a concept as verification, verification. Sometime in the 18th century, people began to actually try to test hypotheses. And these checks became more and more.

So, in the book "Pseudoscience and the Paranormal" by Jonathan Smith there are many references to real checks. It is very important that in the beginning they were occupied by people who wanted to prove the correctness of some concept, and not necessarily astrology. They conducted experiments and processed data honestly. And the results indicated that astrology was not working.

From the point of view of astrophysics, this is also explained quite simply: the planets are light, distant and by themselves do not particularly affect the Earth. The exception is gravitational influence, but it is very weak.

After all, we calmly launch near-earth satellites, without taking into account the influence of Jupiter. Yes, the Sun and the Moon influence them, but Jupiter does not. Like any Mercury or Saturn: one is very light, and the other is very far away.

So, firstly, there is no conceivable agent of influence, and secondly, checks with the desire to find an answer were carried out many times. But people didn't find anything.

Life hacking from Sergey Popov

Art books

There was such a wonderful writer - Yuri Dombrovsky, who has a book "The Faculty of Unnecessary Things". She describes very important issues for our society: how society works, what can happen in it and what bad things should be avoided.

Also I really love "Dandelion Wine" by Ray Bradbury. There is also a wonderful book about growing up "Don't Let Me Go" by Kazuo Ishiguro.

Popular science books

I recommend the book "Explaining Religion" by Pascal Boyer about the nature of religious thinking. I also recommend The Biology of Good and Evil, in which Robert Sapolsky explains how science explains our actions. There is also a book about how the universe works - "Why is the sky dark" by Vladimir Reshetnikov. And, of course, one of mine - "All the formulas of the world." It's about how mathematics explains the laws of nature.

Films

I don't watch much science fiction. Of the latter, I liked the film "Anon". He takes the most advanced technologies, and clearly not fictional (a telephone booth that does not fly in time) and analyzes deep things.

Music

I always listen to music a lot. There is no quiet and calm place to work, so I put on headphones and work with it. Branches are such: classic rock or some other variants of rock, jazz. When I like some music, I immediately post it on my social networks.

I listen to a variety of progressive rock. Probably the best thing that has happened from my old man's point of view in recent years is Math rock, that is, mathematical rock. This is a very interesting style that is close to me. It is not as mournful as shoegazing, from which you can get depressed until you find something worthy. To make it clear what I like specifically, I'll call the group Clever Girl and the Italian Quintorigo.