Georges Lemaître

It’s the birthday of Georges Lemaître, who was born in 1894 in Charleroi, Belgium. Lemaître studied civil engineering at the Catholic University of Louvain before serving in the Belgian army during World War I. After the war he trained to become a priest and a cosmologist. He succeeded in both endeavors. In 1923 he was ordained a Catholic priest. In 1927 he published his most famous paper, “A Homogeneous Universe of Constant Mass and Growing Radius Accounting for the Radial Velocity of Extragalactic Nebulae,” in which he applied Albert Einstein’s theory of general relativity to the entire universe. According to Lemaître’s analysis, the universe was in a state of constant expansion, having begun at a specific point in time. Two years later, Edwin Hubble published his observations of distant galaxies that supported the idea. Although Lemaître remained a devout Catholic, he opposed efforts to link the creation and expansion of the universe to divine action. He successfully persuaded Pope Pius XII to refrain from making proclamations about cosmology. Lemaître died on 20 June 1966, two years after the discovery of cosmic microwave background radiation provided experimental evidence in favor of his bold idea.

Date in History: 17 July 1894