Georges Lemaître, (born July 17, 1894, Charleroi, Belgium—died June 20, 1966, Leuven), Belgian astronomer and cosmologist who formulated the modern big-bang theory, which holds that the universe began in a cataclysmic explosion of a small, primeval "super-atom.". A civil engineer, Lemaître served as an artillery officer in the Belgian This graphic shows a timeline of the universe based on the Big Bang theory and inflation models. (Image credit: NASA/WMAP) SANTA CLARA, Calif. — Our universe could have popped into existence 13. dwlJ.

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