Conceptual image of The Big Bang Theory. Timeline spanning from the first few seconds with the formation of quarks and electrons. These combine to form neurons and protons which in turn develop into planets, galaxies and eventually into the ever expanding universe approximately 15 billion years later. Georges Henri Joseph ?douard Lema簾tre (July 17, 1894 - June 20, 1966) 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. Lema簾tre 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" or the "Cosmic Egg".