Astronomy Bio...Georges Edouard Lemaitre

Jay Bitterman

Georges Edouard Lemaitre was a Belgian cosmologist and priest who was fascinated with creation and the origin of the universe. He devised the concept of what later became known as the "Big Bang" theory.

Lemaitre was born in Charleroi on July 17, 1894. He died at Louvain on June 20, 1966. Trained as a civil engineer, he served as an artillery officer with the Belgian army during World War I. After the war, in 1923, he entered a seminary, where he was ordained a priest. He nevertheless continued a steady interest in science. From 1923 to 1924 he visited the University of Cambridge to study solar physics and met Arthur Eddington. Afterwards he spent two years in the United States, at the Massachusetts Institute of Technology. While he was there he was influenced by the theories of Edwin Hubble and the Harvard astronomer Harlow Shapley regarding the likelihood of an expanding Universe.

In 1927 he returned to his native country with a better insight into the thinking of his contemporaries and was made Professor of Astrophysics at the University of Louvain. In 1933 he published his Discussion on the Evolution of the Universe, which stated the theory of the Big Bang. In 1946 he published his Hypothesis of the Primal Atom.

The main feature of Lemaitre's theory, first formulated in 1931, was that the beginning of the universe stemmed from what he believed to be a "primal atom". He visualized this atom as a single unit, an incredibly dense "egg" that contained all the material for the Universe within a sphere about thirty times larger than the Sun. In his view, this occurred somewhere between 20,000 and 60,000 million years ago when this atom exploded, sending out its matter in all directions. Then a balancing act occurred between expansion and contraction. Ultimately expansion won. Since then (around 9,000 million years ago) the galaxies have continued to drift farther away from each other. The significance of this theory is not so much its affirmation of the expansion of the Universe as its presumption of an event to initiate the expansion.

In 1946 George Gamow improved on Lemaitre's basic theory by contemplating the Big Bang from just before the event to just after, thus giving the Big Bang itself a definite beginning and a definite end and a scientific existence in between. However, Lemaitre's and Gamow's solutions were for a time somewhat overshadowed by the invention of the radio telescope, which began to reveal aspects of the Universe previously unknown. Hermann Bondi, Thomas Gold, and Fred Hoyle, working at Cambridge, put forward their "Steady State" theory, in which they saw the Universe as having no beginning and no end. Stars and galaxies were created, went through a life cycle and died, to be replaced by new matter being created out of "nothingness" (possibly hydrogen atoms).

During the 1940s and early 1950s, the Steady State theory was a serious rival to Lemaitre's and Gamow's Big Bang, but recently the Steady State theory has been virtually abandoned. Researchers such as Martin Ryle and others have shown that the Universe may simply undergo periods of total expansion and total contraction that will go on indefinitely.

Published in the July 1999 issue of the NightTimes