World War I was a terrible war, with many deaths and horrors on the battlefields. Still troubled by what he had gone through, he resumed his studies, taking up physics and mathematics and preparing for priesthood. Under the tutalege of Charles de la Vallée-Poussin, he earned a doctorate in 1920 from the Université Catholique de Louvain (UCL) with a thesis entitled l'Approximation des fonctions de plusieurs variables réelles (Approximation of functions of several real variables). He moved on to the Malines seminary and was ordained as a priest in 1923. In the meantime, he discovered Einstein's Theory of Relativity.
The Curious PriestGeorges-Henri Lemaitre had an insatiable curiosity, which made him a natural scientist. After his ordination, he studied at the University of Cambridge's solar physics laboratory (192324) followed by the Massachusetts Institute of Technology, Cambridge (192527). During these studies, he took an interest in the works of American astronomers Edwin P. Hubble and Harlow Shapley dealing with the expanding universe.
In the meantime, in 1925, Lemaître took a position as a part time lecturer at the Université Catholique de Louvain (UCL). It was here he began down the path towards the thesis that would bring him to the attention of the world. In 1927, he accepted a full time position at UCL and released his work entitled Un Univers homogène de masse constante et de rayon croissant rendant compte de la vitesse radiale des nébuleuses extragalactiques (A homogeneous Universe of constant mass and growing radius accounting for the radial velocity (radial velocity: Velocity along the line of sight toward or away from the observer) of extragalactic nebulae).
An Explosive TheoryThis paper explained the expanding universe in a new way, and within the framework of the General Theory of relativity. Initially, many scientists, including Albert Einstein, himself, were skeptical. However, further studies by Edwin Hubble, seemed to prove the theory. Initially called the "Big Bang Theory" by its critics, the name eventually stuck. Even Einstein was won over, standing and applauding at a Lemaitre seminar, saying "This is the most beautiful and satisfactory explanation of creation to which I have ever listened."
Georges-Henri Lemaitre continued to advance science throughout his life. He studied cosmic rays and worked on the three-body problem. His published works include Discussion sur l'évolution de l'univers (1933; Discussion on the Evolution of the Universe) and L'Hypothèse de l'atome primitif (1946; Hypothesis of the Primeval Atom).
On March 17, 1934, he received the Francqui Prize, the highest Belgian scientific distinction, from King Léopold III, for his work on the expanding universe. In 1936, he was elected a member of the Pontifical Academy of Sciences, where he became the president in March 1960, remaining so until his death. He was also named prelate in 1960. In 1941, he was elected member of the Royal Academy of Sciences and Arts of Belgium. In 1941, he was elected member of the Royal Academy of Sciences and Arts of Belgium. In 1950, he was given the decennial prize for applied sciences for the period 1933-1942. In 1953 he received the very first Eddington Medal award of the Royal Astronomical Society.
He died on the 20th of June 1966.