Lemaitre proposes an expanding universe

The Belgian priest and physicist Georges Lemaitre published a paper in 1927 showing that Einstein's equations allow a universe that expands, and that the redshifts of distant galaxies match such an expansion. He even estimated the rate at which galaxies recede. In 1931 he proposed that the universe began from a 'primeval atom', the first form of what became known as the Big Bang theory. Einstein at first resisted, but accepted the idea after Hubble's observations. Lemaitre's article appeared in French in a little-read Belgian journal, which delayed its recognition.

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