Priest, astronomer and physics professor Georges Lemaitre was born on 17 July, 1894, and Tuesday's Google Doodle celebrates what would've been his 124th birthday.
Lemaitre proposed that the universe began as a single primordial atom and described his theory as "the Cosmic Egg exploding at the moment of the creation" -- which later became known as the Big Bang theory -- in 1931.
He also stated his belief that the universe was expanding in a 1927 paper and Edwin Hubble would substantiate this idea two years later.
In 1934, Lemaitre was given Belgium's highest scientific accolade, the Francqui prize. One of his nominators was Albert Einstein, who had previously dismissed the physics behind his Cosmic Egg theory as "atrocious."
Lemaitre died on June 20, 1966, but would have a crater on the moon named after him in 1970.