Georges Lemaitre

Georges Lemaître was a Belgian priest, astronomer and professor of physics at the Catholic University of Leuven.

He proposed the theory of the expansion of the universe, widely misattributed to Edwin Hubble. He was the first to derive what is now known as Hubble's law and made the first estimation of what is now called the Hubble constant, which he published in 1927, two years before Hubble's article. Lemaître also proposed what became known as the Big Bang theory of the origin of the universe, which he called his "hypothesis of the primeval atom."

Born in 1894, after WW1 he studies Physics at at the Catholic University of Leuven. In 1923, he became a graduate student in astronomy at the University of Cambridge. He worked with Arthur Eddington, who introduced him to modern cosmology, stellar astronomy, and numerical analysis.

Lemaître was a pioneer in applying Albert Einstein's theory of general relativity to cosmology.