(July 05.1923 - September 18.2002)

The eminent Russian scientist and Corresponding member of Russian Academy of Sciences Sergey Ivanovich Nikolsky passed away after a long decease on 18 September of 2002.

S.I.Nikolsky was borne on July 5 in 1923 in Liwni, the town of Orel region.

In 1941 he was graduated from the school and in October of 1941 he joined Red Army. At the time of the Second World War in August 1942 he was severely wounded. After recovering in 1943 S.I.Nikolsky entered the Physical Department of Moscow State University and was graduated from it in 1948.

S.I.Nikolsky was one of the leading scientists in the field of Cosmic Ray Physics and High Energy Physics. His name is connected with investigation of primary cosmic ray energy spectrum and composition, where he used for the first time the method of calorimetry of all Extensive Air Shower components. The "Nikolsky spectrum", "Nikolsky composition" and "Nikolsky point" of Cosmic Ray intensity are world wide known.

The big complex arrays for study of Extensive Air Showers and interactions of high energy hadrons was created by S.I.Nikolsky at the Pamirs and Tien-Shan Mountain Stations. Using the world biggest ionization calorimeter a number discoveries was made by S.I.Nikolsky, such as long-flying component, increasing of transverse momentum of secondary particles at high energies and other. In the recent years the big flux of delayed neutrons in EAS and several irregularities in showers at energies above 1016 eV was found at Tien-Shan. He proposed the idea that these phenomena can be understood with the peculiarities of interactions at high energies. He proposed also many other fruitful ideas which were used by many researchers.

S.I.Nikolsky built at Tien-Shan big gamma-ray telescope and performed investigations big number of galactic and metagalactic gamma-ray sources. It was found the new sources of gamma-rays Sejfert Galactic NGC 1275 and galactic nuclei 3C454 and 1739+522.

S.I.Nikolsky was one of co-creators of giant array for Extensive Air Shower study in Yakutsk and unique array "ANI" in Armenia.

S.I.Nikolsky realized cooperation with scientists from different countries - Bulgaria, Hungary, Poland and India. 4 gamma-telescopes were built in India using project of telescope elaborated in FIAN and cooperative investigations in the field of gamma-astronomy had been planned.

Many students were educated by Sergey Ivanovich as at the Pamirs, Tien-Shan and Aragatz mountain stations, so in Moscow Engineering Physical Institute where he was a professor up to his last days.

S.I.Nikolsky was large-scale organizer of Russian science: many years he was the vice-director of P.N.Lebedev Physical Institute of Russian Academy of Sciences and director of Nuclear Physics and Astrophysics Department of this Institute. His achivements was marked with several high governmental decorations and Lenin prize.

The death of Sergey Ivanovich Nikolsky is the great loss for his colleagues, friends and world scientific community.