Whose theory is the Big Bang?

Using Einstein’s general relativity, Georges Lemaître showed in 1927 that the universe could be expanding and linked this to the redshifts of galaxies, two years before Edwin Hubble’s famous observations. In 1931 he proposed that the universe began from an extremely dense “primeval atom”. Russian physicist Alexander Friedmann had found expanding-universe solutions in 1922, and George Gamow and colleagues later developed the theory of how the first elements formed. The name “Big Bang” was coined, somewhat mockingly, by rival astronomer Fred Hoyle on BBC radio in 1949. The discovery of the cosmic microwave background in 1965 provided strong evidence for the theory.