Nikolay Umov

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Nikolay Alekseevich Umov (Russian: Николай Алексеевич Умов) was a famous Russian physicist and mathematician, and discoverer of the Umov-Poynting vector concept and Umov effect.

Umov was born in January 23, 1846 in Simbirsk (nowadays Ulyanovsk) in family of a military doctor. Umov graduated from Mathematics department of Moscow State University in 1867; became a professor of Physics in 1875. Umov self-educated in theoretical physics using works of Gabriel Lamé, Clebsch and Clausius, which has much to do with originality of his ideas.

Umov was the first who introduced in physics such basic concepts, as speed and direction of movement of energy - which is associated now with Umov-Poynting vector, and density of energy in the given point of space. During his work in Odessa in 1873-1874, Umov published first papers representing major ideas of energy movement. In his first works of this period, he considered potential energy as kinetic energy of some environments "imperceptible for us ". From this hypothesis, he made a conclusion: it is always possible to specify a place where the energy is in. Therefore, it is natural to raise the question about movement of energy. In his following works, Umov did not bind himself to this hypothesis about the nature of potential energy, but was guided by the principle of energy conservation only. After having formulated the concept of density and movement of energy, he wrote differential equations of energy movement in the elastic media and in the fluid. The fundamental "Encyklopǎdie der mathematischen Wissenschaften” states: "N.Umov yet in 1874 had solved a problem of the movement of energy in liquid and elastic media in completely generalized view. However, the intense attention to this view has been attracted only after Poynting has presented a stream of electromagnetic energy based on Maxwell equations" (10 years after Umov's publications.)

In 1875, Umov has solved a general problem of distribution of electric currents in conducting surfaces of any kind. In 1888-1891 he investigated experimentally the diffusion in water solutions, polarization of light in opaque media, discovered effect of chromatic depolarization of light.

Umov became the head of Physics department of Moscow State University after Aleksandr Stoletov died in 1896. Together with Pyotr Lebedev, Umov actively participated in founding the Physical Institute by the university. In 1900th he had conducted a thorough analysis of many Gauss formulae regarding terrestrial magnetism, which allowed to define secular changes of the of the Earth's magnetic field.

Umov organized a set of educational societies; he has been the president of the Moscow Society of Nature Explorers during 17 years. He was one of the first Russian scientists who acknowledged the significance of the theory of relativity. In 1911, he along with a group of leading professors left Moscow University in protest of reactionary actions of government. Umov died in January 15, 1915 in Moscow.