(1894-1966) Belgian cosmologist who in 1933 proposed the Big Bang theory of the origin of the universe. US astronomer Edwin Hubble had shown that the universe was expanding, but it was Lemaître who suggested that the expansion had been started by an initial explosion, the Big Bang, a theory that is now generally accepted.
Lemaître was born in Charleroi, trained as a civil engineer and also ordained a priest. He studied astrophysics in the UK at Cambridge and in the US at the Massachusetts Institute of Technology, where he became influenced by the theories of Hubble and Harvard astronomer Harlow Shapley concerning the likelihood of an expanding universe. Lemaître was made professor of astrophysics at the University of Louvain 1927.
Lemaître visualized a “primal atom”, an incredibly dense “egg” containing all the material for the universe within a sphere about 30 times larger than the Sun. Somewhere between 20,000 and 60,000 million years ago, in his view, this atom exploded.
Lemaître’s works include Discussion on the Evolution of the Universe 1933 and Hypothesis of the Primal Atom 1946.