He looked beyond the Big Bang: a colleague remembers academician Alexei Starobinsky

It was he, before Stephen Hawking, who proved that black holes can emit light, it was he who described the processes preceding the Big Bang… Russian theoretical physicist, author of works on gravity and cosmology, who worked at the Landau Institute of Theoretical Physics of the Russian Academy of Sciences, Alexey Starobinsky died on Thursday at the age of 76. We talked with the director of the institute, Igor Kolokolov, about the contribution that the academician made to modern science.

Starobinsky became interested in cosmology back in the 1970s, when he was still very young, he was not even 30 years old. At that time, according to his colleagues, cosmology was the lot of only venerable academics, and therefore Starobinsky’s phenomenon caused something like surprise among some. Nevertheless, when asked why you came to cosmology, the young man confidently and at the same time modestly answered: “To solve problems.”

Alexey Alexandrovich was born on April 19, 1948 in the family of Muscovite radiophysicists Alexander Starobinsky and Natalia Kerzhentseva. After graduating from the eleven-year physics and mathematics school No. 5 in 1966, he entered the physics department of Moscow State University.

His teacher Yakov Borisovich Zeldovich once put forward a hypothesis that rotating black holes should produce light – pairs of particles-antiparticles. This fascinated the young theorist, and a year after graduating from Moscow State University, in 1973, Starobinsky proved this theory. Literally a year after this, the well-known Stephen Hawking would put Zeldovich’s idea of ​​the generation of light by black holes and Starobinsky’s corresponding proof into his work, and the phenomenon would be unfairly called “Hawking radiation.” The only difference was that Zeldovich and Satrobinsky were talking about the induced (increased rotation) light of black holes, and Hawking was talking about the spontaneous light of even a non-rotating hole (although this idea logically followed from the previous one).

But the main work of Alexei Alexandrovich is rightfully considered to be his inflationary theory of the Universe.

“Aleksey Starobinsky is rightfully considered an outstanding scientist and the father of modern inflationary cosmology,” says Igor Kolokolov. “He supplemented with his model the theory of Albert Einstein and confirmed the theory of the expansion of the Universe of our compatriot Alexander Friedman, who put it forward in 1922.

– What is it?

– Before him, according to Friedman, everyone began counting the life of our Universe from the Big Bang, as a result of which all the matter known to us appeared. Starobinsky predicted and, most importantly, later verified in practice, the existence of an earlier process – the inflation of the Universe, which preceded the hot Big Bang.

– So there were two of them?

– You can imagine it that way. That is, there was a certain singularity – a certain quantum state, from which something arose as a result of one explosion, then, after 10 to minus 42 seconds, according to Starobinsky’s theory, this “something” began to inflate exponentially, and this process ended with the second Big Bang with the emergence of modern matter.

– Could this first Big Bang have been like a flash?

– No one could confirm or deny this to us (smiles). As Alexey Aleksandrovich himself explained his theory, the inflation that preceded the big bang began with a quantum field the size of a meter. It happened exponentially, in all directions. Together with him, both space and time were born, which did not exist before.

– How did Starobinsky manage to prove this?

– At that initial stage of the origin of the Universe, according to his theory, quantum fluctuations should have been born, in other words, special gravitational waves, they are also called relic waves, that is, echoes of an ancient era. So, Starobinsky’s model is valuable because it has been confirmed – relic gravitational waves have already been partially registered by scientists.

We are confident that further, more accurate measurements and observations will provide complete confirmation of Starobinsky’s picture of an inflating early Universe. It’s a pity that he left early, because if he had lived another 10 years (that’s how long, in my opinion, is needed to prove his model), he certainly would have received the Nobel Prize.

Alexander Alexandrovich was an outstanding theoretical physicist and it is important that he constantly correlated all his theoretical constructions with existing observations and made specific predictions for future observations. He made inflationary theory part of normal physics.

Conversations over a cup of tea

After talking about the serious work of Alexei Starobinsky, we talked with Igor Valentinovich about cosmological hypotheses that do not have any evidence at all. Theorists allow themselves to express these hypotheses in moments of rest, as fantasies about how our world might actually be structured.

– Igor Valentinovich, what, according to Starobinsky, happened before the inflation stage?

“It was a fantasy that while that same field was inflating for thousandths of a second, it could lay the foundation of more than one of our Universes. There could have been about 10 to the 70th power like ours at that moment! And then they themselves gave birth to their Big Bangs. They know nothing about each other, because each is beyond the event horizon for its neighbor.

– So what, in those universes everything can be like ours?

– There can be many universes, but the number of events in them is finite. It is possible that there is exactly the same Universe as ours, with exactly the same us – the probability of this is not zero. But Ivan Ivanovich from a parallel universe may be slightly different from an identical character from ours, for example, ours drinks, and that one is a teetotaler.

“Then it turns out that his life turns out differently.” A kind of model of our possible life scenarios! But still, it seems too fantastic to me that our doubles could exist somewhere.

– Yes, for this a parallel universe with the same set of quanta would have to appear. But we will never check this anyway, because such universes, even if they exist, are fundamentally unattainable for each other.

These are interesting topics that my colleague Alexey Alexandrovich and I often raised over a cup of tea. In communication he was an open, pleasant person, I had a completely normal working relationship with him. It’s a shame that he is no longer with us.