RESSELL Henry Norris (Russell Henry Norris)

(1877-1957)
Born October 25, 1877 in Oyster Bay (pc. New York). He studied at the Charles Young at Princeton University and from R. Ball, University of Cambridge. In 1905, Jung's successor at Princeton, served as professor of astronomy and director of the observatory until 1947. In 1922-1942 was also a member of the Mount Wilson Observatory. In 1947-1952 he worked at Harvard Observatory. For a long time Ressell was researching the connection between the spectra of stars and their luminosity. In 1913, regardless of the Danish astronomer E. Hertzsprung built diagram, . connecting these characteristics (Hertzsprung - Ressella), . in 1913-1914 has formulated the concept of stellar evolution, . according to which the main source of energy from the star is its gravitational contraction,
. An evolution is determined by continuous variation of density of stars: from red giants on the giant branch for stars of spectral types A and B (heating), then the branch dwarfs in solar-type stars to the red dwarf (cooling). By mid-1920 Ressell revised his theory, suggesting the existence of the stars of other energy sources. In 1912 a general theory of eclipsing variable stars. First determined the contents of chemical elements in the atmosphere of the Sun (1929), received the evaluation of chemical elements in the universe.
Ressell was a member of many academies of sciences, was president of the American Astronomical Society, was awarded numerous medals and prizes. Died in Princeton Ressell (pc. New Jersey) 18 February 1957.