Georges Lemaître comes in with a bang

In 1927, Catholic priest Georges Lemaître published a paper in the Annales de la Societe scientifique de Bruxelles in which he reviewed the General Theory of Relativity, published by Albert Einstein in 1916, and found that not only was the Universe expanding, but that it had originated at a finite point in time.

Few people took notice of Lemaître’s conclusions, but one person who did was Einstein himself, who told him: “Your calculations are correct, but your grasp of physics is abominable.”

By 1929, however, it was Einstein’s calculations that had come under fire, stemming from “systematic observations of other galaxies” made by American astronomer Edwin Hubble, and Lemaitre’s findings began to find supporters.

The dispute, according to the article “A Day Without Yesterday: Georges Lemaitre & the Big Bang” published by the Catholic Education Resource Centre (CERC), came about from “a conflict between [the] seeming contradiction between visual observation and the theory of relativity”.  

In 1929 Britain’s Royal Astronomical Society met to examine the conflicting data, and renowned mathematician Sir Arthur Eddington volunteered to work out a solution.

Hearing of this, Lemaître sent Eddington a copy of his 1927 paper, and in March 1931 the Society published an English translation in its Monthly Notices.

Most scientists who read Lemaitre’s paper, CERC says, “accepted that the universe was expanding” but “resisted the implication that the universe had a beginning”.

One of those who certainly resisted was Eddington, who wrote in the journal Nature that the notion of a beginning of the world was “repugnant”.

Lemaître responded with a letter to Nature, headlined “The beginning of the world from the point of view of quantum theory”:

“Sir Arthur Eddington states that, philosophically, the notion of a beginning of the present order of Nature is repugnant to him. I would rather be inclined to think that the present state of quantum theory suggests a beginning of the world very different from the present order of Nature. Thermodynamical principles from the point of view of quantum theory may be stated as follows: (1) Energy of constant total amount is distributed in discrete quanta. (2) The number of distinct quanta is ever increasing. If we go back in the course of time we must find fewer and fewer quanta, until we find all the energy of the universe packed in a few or even in a unique quantum.”

This clash between the two was perhaps surprising, given that years earlier Eddington the professor had said of Lemaître the scholar, that he was “a very brilliant student, wonderfully quick and clear-sighted, and of great mathematical ability”, according to a profile of Lemaître published by the American Museum of Natural History.

As his findings gained acceptance, more people began to comment on the fact that Lemaitre was a Catholic priest. Duncan Aikman, writing in the New York Times in 1933, in an article headlined “Lemaître follows two paths to the truth: The famous physicist tells why he finds no conflict between science and religion”, says, “His view is interesting and important not because he is a Catholic priest, not because he is one of the leading mathematical physicists of our time, but because he is both.”

Lemaître was born in 1894 in Charleroi, Belgium. He was educated in Jesuit and Catholic schools, studying physics and mathematics. He was ordained as a priest in 1923 and in 1924 travelled to Britain, to Cambridge University, where he studied under Eddington.

He then went to the US and earned a PhD in physics from the Massachusetts Institute of Technology. In 1925 he returned to Belgium as a lecturer at the Catholic University of Louvain, near Brussels. He continued teaching and writing until his death in 1966.

Danish historian Helge Kragh, in a 2012 article titled “The wildest speculation of all: Lemaître and the primeval-atom Universe”, part of the Astrophysics and Space Science Library book series, says that although “Lemaître was indeed the father of big-bang cosmology, his brilliant idea was only turned into a viable cosmological theory by later physicists”.

Indeed, the term “big bang theory” was coined by British astronomer Fred Hoyle, who never accepted it was a theory on the origin of the Universe and used it derisively.

In 2018, half a century after Lemaître’s death, what was known as the Hubble Law – describing how galaxies move away from each other – was renamed the Hubble – Lemaître Law.