The Big Bang

The idea that the universe had a beginning was first suggested by the general theory of relativity, completed by Albert Einstein in 1916. Einstein's equations, which describe the structure of space and time, suggested that the universe should not be static, but that it ought to be expanding. Both Einstein and other physicists realized this consequence of the theory fairly early on, but at the time most scientists believed wholeheartedly that the universe was static. Einstein himself was so swayed by this idea that rather than accept his equations at face value, he added and extra (and extraneous) term to this formulae to still the cosmic motion they implied. Later, when it was discovered that the universe was indeed expanding, Einstein called this "the greatest blunder of my life". He had missed the chance to make what would surely have been one of the most spectacular predictions in the history of science.

One of the very first people to take seriously the idea of an expanding universe, and hence the idea of a cosmic origin, was the Belgian priest Father George Lemaitre. An early relativity physicist, Lemaitre suggested that the universe began with what he called a "cosmic atom". In his cosmic evolutionary scenario, this superatom then broke apart, gradually forming all the atoms and particles that make up the universe today. Physicists have since rejected Lemaitre's cosmic atom, but they have embraced his idea of a universe that began as a tiny dense point which expanded outward to produce the vast structure we see today. Father Lemaitre had an illustrious career as a cosmologist, and for many years was head of the Pontifical Academy of Sciences, situated in the elegant grounds of the Vatican.

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