Timeline

1916

Albert Einstein proposes the theory of General Relativity, which predicts that the universe cannot be static.

1929

Edwin Hubble provides compelling evidence that the universe is expanding.

1931

Georges Lemaître proposes that the universe had a beginning - an explosion that resulted in the expansion Hubble observed.

1946

George Gamow succeeds in explaining the relative abundance of hydrogen and helium in the universe with the Big Bang model.

1948

George Gamow, Ralph Alpher and Robert Herman predict that radiation left over from the Big Bang would be observable. 

Steady State theory is proposed by Fred Hoyle, Thomas Gold and Hermann Bondi to rival the Big Bang theory.

1950

Hoyle coins the phrase "big bang" to describe the beginning of the universe proposed in the rival theory. He intends it as a derogatory remark. The phrase sticks.

1952

Pope Pius XII announces that Big Bang cosmology affirmed the notion of a transcendental creator and was in harmony with Christian teaching.

1958

Fred Hoyle and William Fowler show how the heavy chemical elements that fill our bodies, such as oxygen, carbon and iron, were manufactured in giant stars which later exploded and from whose relics the solar system was born.

1965

Arno Penzias and Robert Wilson detect the cosmic microwave background radiation, leading to the rejection of Steady State theory in favour of the Big Bang theory.

1990

John C. Mather, using NASA's COBE satellite, measures the properties of the CMBR, revealing the predicted blackbody form.

1998

Brian Schmidt, Adam Reiss and Saul Perlmutter publish research showing that the expansion of the universe is accelerating.