Alexander Friedmann

Alexander Alexandrovich Friedmann (1888 to 1925) was a Russian and Soviet physicist and mathematician who originated the theory that the universe is expanding, governed by the set of equations now known as the Friedmann equations. Born in Saint Petersburg, he took his degree at St. Petersburg State University in 1910 and lectured at the Saint Petersburg Mining Institute. He served in World War I as an army aviator, instructor and head of an airplane factory. In 1922 he introduced the idea of an expanding universe containing moving matter and in 1924 worked out all three curvature models, which became the basis of the Friedmann-Lemaitre-Robertson-Walker metric. His interests also covered hydrodynamics and meteorology, and in 1925 he became director of the Main Geophysical Observatory in Leningrad.