The Big Bang was first proposed by a Catholic priest
Georges Lemaître was an ordained Belgian priest and a physicist. He was the first to argue that receding galaxies meant the universe is expanding, and his hypothesis of a primeval atom is now regarded as the earliest version of the Big Bang. He also insisted the Bible was never meant to be a science textbook.
Born in Charleroi in 1894, the son of a glassworks owner, Lemaître wanted a religious life but was persuaded by his father to train first as a mining engineer at Louvain. The First World War interrupted him. He fought at the Battle of the Yser, lost his chance of promotion for pointing out a mathematical error in the official artillery manual to his instructor, and still received the Belgian War Cross with bronze palm from King Albert I, one of only five ordinary soldiers so honoured.
After the war he switched to physics and mathematics, earning a doctorate in 1920, and entered a seminary for mature students, where he taught himself general relativity in his spare time. A 1922 thesis showing that Einstein's field equations in their most general form include a cosmological constant won him a travel prize of 8,000 Belgian francs. Ordained in 1923, he left ten days later for Cambridge to work with Arthur Eddington, then spent a year with Harlow Shapley at Harvard studying spiral nebulae while enrolled at MIT.
Back at Louvain, where he taught from 1927 until 1964, he linked the observed relationship between galaxy distance and speed, now called the Hubble-Lemaître law, to a solution of Einstein's equations for a uniform universe. He favoured a positive cosmological constant to square the universe's age with the ages of the oldest stars. He was also an early adopter of computers, and with Manuel Sandoval Vallarta showed in the 1930s that Earth's magnetic field bends cosmic rays, so they must carry charge.
As a young man he had shown the Catholic writer Léon Bloy an essay reconciling Genesis with modern science; Bloy was unimpressed. Lemaître later rejected such efforts, arguing that faith and science answer different questions. The Church honoured him anyway: Pope John XXIII made him a monsignor in 1960, the same year he became president of the Pontifical Academy of Sciences. In 1953 he received the Royal Astronomical Society's first Eddington Medal.
Source: Georges Lemaître
