Yakov Borisovich Zeldovich ForMemRS (Russian: Я́ков Бори́сович Зельдо́вич , Belarusian: Я́каў Бары́савіч Зяльдо́віч ; 8 March 1914 – 2 December 1987), also known as YaB, was a prominent Soviet physicist of Belarusian heritage. He made important contributions to physical cosmology, the study of thermonuclear reactions, combustion, and fluid movement.

Starting in 1943, Zeldovich, who taught himself physics, played a key role in the Soviet Union’s nuclear weapons program. In 1963, he returned to academic work, where he conducted important research on the study of black holes and expanded knowledge in physical cosmology.

Biography

Yakov Zeldovich was born in 1898 to a Belarusian Jewish family in a house owned by his grandfather in Minsk, Belarus. In 1914, his family moved to Saint Petersburg, Russia. They lived there until August 1941, when they left the city with other scientists from the Institute of Chemical Physics to escape the Axis powers’ invasion of the Soviet Union. They stayed in Kazan, Russia, until the summer of 1943, when Zeldovich moved to Moscow.

Zeldovich’s father, Boris Naumovich Zeldovich, was a lawyer. His mother, Anna Petrovna Zeldovich (born Kiveliovich), was a translator who worked between French and Russian and was part of the Writer’s Union. Although his family was religiously Jewish, Zeldovich did not believe in any religion and considered himself an atheist.

Zeldovich was self-taught and known for his ability to learn and understand many different subjects. In May 1931, he began working as a laboratory assistant at the Institute of Chemical Physics of the Soviet Academy of Sciences. He stayed connected to the institute for the rest of his life. As a laboratory assistant, he studied physical chemistry and gained respect from senior scientists at the institute.

From 1932 to 1934, Zeldovich took undergraduate classes in physics and mathematics at Leningrad State University (now Saint Petersburg State University). Later, he attended technical physics lectures at the Leningrad Polytechnic Institute (now Peter the Great St. Petersburg Polytechnic University).

In 1936, Zeldovich earned the Candidate of Science degree, which was the Soviet equivalent of a PhD. His thesis focused on the topic of “adsorption and catalysis on heterogeneous surfaces.” His research centered on the Freundlich adsorption isotherm, and he explained the theoretical basis for this scientific observation.

In 1939, Zeldovich completed a dissertation on the mathematical theory of nitrogen oxidation. He earned the Doctor of Sciences degree in mathematical physics after his work was reviewed by Alexander Frumkin. His research identified the mechanism for nitrogen oxidation, which is now known in physical chemistry as the thermal NOx mechanism or Zeldovich mechanism.

Zeldovich was considered a key figure in the Soviet nuclear weapons program. His travel outside the Soviet Union was limited to Eastern Europe, and he was closely monitored by Soviet security. After German chemist Otto Hahn discovered nuclear fission in 1939, Soviet scientists, including Igor Kurchatov and Yulii Khariton, began studying nuclear fission.

In May 1941, Zeldovich worked with Khariton to develop a theory about nuclear reactions under critical conditions. Their research expanded into studies of ignition, combustion, and detonation. These studies explained phenomena that had not been fully understood before. The modern theory of detonation is now called the Zeldovich-von Neumann-Dohring, or ZND, theory. This work involved complex calculations about fast neutrons and was delayed due to the German invasion of the Soviet Union in 1941. In 1942, Zeldovich was sent to Kazan to work on conventional gunpowder for the Soviet military, while Khariton focused on designing new weapons.

In 1943, Joseph Stalin ordered the development of nuclear weapons, led by Igor Kurchatov. Kurchatov asked Stalin to move Zeldovich and Khariton to Moscow for the nuclear program. Zeldovich joined Kurchatov’s team in Moscow and became head of the theoretical department at Arzamas-16 in 1946.

With scientists Isai Gurevich, Isaak Pomeranchuk, and Khariton, Zeldovich created a report on using nuclear fusion to release energy through an atomic explosion. He presented this to Kurchatov. Zeldovich’s knowledge was influenced by German physicist Klaus Fuchs and American physicist Theodore Hall, who worked on the American Manhattan Project.

In 1949, Zeldovich led a team that conducted the first nuclear test, the RDS-1, which was based on designs obtained through espionage in the United States. He continued his research on explosive theory and introduced the idea of a hydrogen bomb to Andrei Sakharov and others. During his work on nuclear weapons, Zeldovich made important contributions to radiation hydrodynamics and the study of matter under extreme pressure.

Between 1950 and 1953, Zeldovich performed calculations that helped develop the hydrogen bomb. These calculations were confirmed by Andrei Sakharov, though both teams worked separately on thermonuclear fusion. Sakharov later changed the approach to fusion with the help of Vitaly Ginzburg in 1952. Zeldovich remained involved in nuclear testing until October 1963, when he left the program to join academia.

In October 1973, during the Yom Kippur War, Zeldovich left a letter with fellow Soviet Jewish physicist Ilya Lifshitz. He wrote that if the Soviet Union launched a nuclear attack on Israel, he intended to commit suicide.

Academia and cosmology

In 1952, Zeldovich began working in the field of elementary particles and their changes. He predicted that a pi meson would undergo beta decay. With Semyon Gershtein, he noticed the similarity between the weak and electromagnetic interactions. In 1960, he predicted the muon catalysis (specifically, muon-catalyzed dt-fusion) phenomenon. In 1977, Zeldovich and Fyodor Shapiro were awarded the Kurchatov Medal, the highest honor in nuclear physics of the Soviet Union. The award recognized their work in predicting the characteristics of ultracold neutrons, their detection, and study. He became an academician of the USSR Academy of Sciences on June 20, 1958. From 1965 until January 1983, he led a division at the Institute of Applied Mathematics of the USSR Academy of Sciences.

In the early 1960s, Zeldovich began research in astrophysics and physical cosmology. In 1964, he and Edwin Salpeter independently proposed that energy from quasars comes from accretion discs around massive black holes. From 1965, he taught at the Department of Physics at Moscow State University and led the division of Relativistic Astrophysics at the Sternberg Astronomical Institute. In 1966, he and Igor Novikov suggested searching for black hole candidates in binary star systems where one star is bright in visible light but dark in X-rays, and the other is dark in visible light but bright in X-rays.

Zeldovich studied the development of the hot universe, the properties of microwave background radiation, the large-scale structure of the universe, and the theory of black holes. With Rashid Sunyaev, he predicted that cosmic microwave background radiation would undergo inverse Compton scattering. This discovery, called the Sunyaev-Zeldovich effect, is now a key tool for studying the universe using telescopes like the Atacama Cosmology Telescope and the South Pole Telescope. He also contributed to understanding the large-scale structure of the universe using Lagrangian perturbation theory (the Zeldovich approximation) and the Burgers' equation approach through the adhesion approximation.

In 1974, Zeldovich and A. G. Polnarev suggested the existence of a gravitational memory effect, where freely falling particles initially at rest move apart after a burst of gravitational radiation passes.

Zeldovich played an important role in developing the theory of black hole evaporation caused by Hawking radiation. In 1971 and 1972, he and Charles W. Misner predicted that rotating Kerr black holes could produce particles. Earlier, in 1965, he predicted that Kerr black holes would split the light from photons in a way similar to the Zeeman effect. During Stephen Hawking’s visit to Moscow in 1973, Zeldovich and Alexei Starobinsky showed Hawking that rotating black holes, according to the quantum mechanical uncertainty principle, should emit particles.

Family

Yakov Zeldovich and his wife, Varvara Pavlovna Konstantinova, had a son and two daughters who were physicists: their son was Boris Zeldovich, and their daughters were Olga Yakovlevna Zeldovich and Marina Yakovlevna Zeldovich.

Yakov Zeldovich also had a daughter named Annushka with O.K. Shiryaeva.

In 1945, he had another daughter named Alexandra Varkovitskaya with Ludmila Varkovitskaya, who was a linguist and folklorist.

In 1958, Yakov Zeldovich had another son with Nina Nikolaevna Agapova. His name was Leonid Yakovlevich Agapov, and he passed away in 2016 at the age of 58.

Awards and honors

Igor Kurchatov called him a "genius," and Andrei Sakharov referred to him as "a man of universal scientific interests." After their first meeting in Moscow, Stephen W. Hawking wrote to Zeldovich: "Now I know that you are a real person and not a group of scientists, like the group called Bourbaki." He was a member of the American Academy of Arts and Sciences (1975), the United States National Academy of Sciences (1979), and the American Philosophical Society (1979).