Big Bang theory proposed

The Big Bang theory holds that the universe began in an extremely hot and dense state and has been expanding ever since. In 1931 the Belgian priest and physicist Georges Lemaitre proposed that the expanding universe had grown from what he called a primeval atom, building on his 1927 work on expanding solutions of Einstein's equations and on Edwin Hubble's 1929 evidence that distant galaxies recede from us. The name Big Bang was coined by the astronomer Fred Hoyle in 1949, who was in fact a critic of the idea and favoured a steady-state universe. The discovery of the cosmic microwave background by Arno Penzias and Robert Wilson in 1964 and 1965 persuaded most scientists that the theory was correct. Current measurements place the beginning of the universe about 13.8 billion years ago.

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