Mathematician, astronomer, and professor of astrophysics
In 1927 he expounded what became known as the Big Bang Theory, now a prevailing cosmological theory, that an expanding universe could be traced back to an originating single point, the "primeval atom". He derived the Hubble-Lemaître law, the observation in physical cosmology that galaxies are moving away from Earth at speeds proportional to their distance and estimated the value for the proportionality constant, both theories confirmed and refined by work by Edwin Hubble.
