Georges Lemaitre
(Date taken unknown)
Georges Lemaitre. Portrait of the Belgian cosmologist and astronomer Georges Edouard Lemaitre (1894-1966). Lemaitre was ordained as a Catholic priest after studying at Louvain University in Belgium. After a spell at the observatories at Cambridge and Harvard, in England and the U.S. respectively, he returned to Louvain as professor of astronomy in 1927. There he found a solution to Einstein's equations of relativity which showed that the universe was expanding from a 'Big Bang'. Lemaitre theorised that the universe must consequently have started out as an extremely dense 'primal atom', which he thought had exploded due to radioactive decay.