One of the deepest trenches in the Atlantic is named after Sergei Vavilov. Why?

The name was given in honor both the research vessel ‘Akademik Sergei Vavilov’, which operated in the area for many years, and Sergei Ivanovich Vavilov, president of the USSR Academy of Sciences.

Specifying the full name is crucial here, because there were two great Vavilovs in Russia: renowned geneticist, botanist and plant breeder Nikolai Vavilov and his equally famous younger brother, Sergei Vavilov (1891–1951) – a physicist and the "father of Soviet optics".

The Vavilov brothers were born in Moscow into the family of a wealthy merchant. Sergei graduated from the Faculty of Physics and Mathematics at Moscow University. The nature of light became the central theme of his research. In the 1920s, he began studying luminescence – a phenomenon in which a substance absorbs energy and subsequently emits it in the form of light. He discovered a fundamental law that now bears his name: Vavilov's law establishes the dependence of the energy output of luminescence on the wavelength of the exciting light. This law has become a classic principle of physical optics.

However, Vavilov's most famous achievement is associated with the Vavilov-Cherenkov effect. In 1933, he proposed that his graduate student, Pavel Cherenkov, study the luminescence of uranium salt solutions when exposed to gamma radiation. When Cherenkov detected a faint blue glow that persisted even in absolutely pure liquids, he initially wanted to switch topics, regarding the phenomenon as an interference or artifact. However, Vavilov insisted that the experiments continue and was the first to realize that this was not luminescence, but a fundamentally new physical phenomenon.

This radiation occurs when a charged particle moves through a transparent medium at a speed greater than the speed of light in that medium. Vavilov-Cherenkov radiation arises from the collective emission of numerous atoms in the medium, located along the particle's trajectory under the influence of its electric field. Thus, it’s not the particle itself that emits the radiation, but the medium through which it moves. The situation is similar to what occurs on the surface of the water when a motorboat moves: the boat generates a wave of disturbance in the water.

For this discovery, Pavel Cherenkov, Igor Tamm and Ilya Frank were awarded the Nobel Prize in Physics in 1958, already after Vavilov’s death.

The scientist was not only an outstanding experimentalist, but also a leader in the scientific community. In 1932, he became a full member of the Academy and, in 19456, was elected president of the USSR Academy of Sciences – the country's highest scientific institution. In this role, he oversaw the reconstruction of Soviet science following World War II. He also founded the Institute of Physics of the Academy of Sciences (FIAN).