Nick Gorkavyi

ABSTRACT
Rudolf Clausius introduced the concept of entropy in 1865 and formulated the second law of thermodynamics, which asserts the inevitability of entropy growth in closed systems. The classic problem of the heat death of the Universe has arisen. The talk considers the modern development of the concept of entropy. Ilya Prigogine proved that all biological and many
physical systems are open systems, and that they successfully resist the growth of entropy. The entropy of gravitational systems does not obey the second law of thermodynamics, because the energy of the gravitational field allows the formation of structures even in closed systems. Of particular importance is the discovery of the entropy of black holes by Bekenstein and Hawking. After calculating the entropy of different subsystems of the Universe, it turned out that the main entropy of the Universe is contained in supermassive black holes, which play a key role in cosmology. This made it possible to construct a model of a cyclic Universe in which entropy does not increase, but changes cyclically along with the oscillating Universe.