Georges Lemaître
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Father Georges-Henri Lemaître (July 17, 1894 – June 20, 1966) was a Belgian Roman Catholic priest, honorary prelate, professor of physics and astronomer.
Fr. or Msgr. Lemaître proposed what became known as the Big Bang theory of the origin of the Universe, although he called it his 'hypothesis of the primeval atom'. He based his theory, first broached in the pages of Nature in 1931, on the laws of relativity set forth by Einstein, among others, although at the time Einstein believed in an eternal universe and had previously expressed his skepticism about Lemaitre's original 1927 paper. A similar solution to Einstein's equations, suggesting a changing radius to the size of the universe, had been proposed in 1922 by Alexander Alexandrovich Friedman, as Einstein informed Fr. Lemaître when he approached him with the theory at the 1927 Solvay Conference (Friedman had also been criticized by Einstein), but it is Fr. Lemaître that made the theory famous with his widely read papers and media appeal. Fr. Lemaître also proposed the theory at an opportune time since Edwin Hubble would soon release his red shift observations that strongly supported an expanding universe and, consequently, the Big Bang theory. In fact, Lemaître derived what became known as Hubble's Law in his 1927 paper, two years before Hubble.
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[edit] Biography
After studying humanities at a Jesuit school (Saint Michel), Lemaître entered the civil engineering school of the Catholic University of Leuven at the age of seventeen. In 1914, at the beginning of World War I, he paused his studies to engage as a volunteer in the Belgian army. At the end of hostilities, he received the Military Cross with palms.
After the war, he undertook studies in physics and mathematics and began to prepare for priesthood. He obtained his doctorate in 1920 with a thesis entitled l'Approximation des fonctions de plusieurs variables réelles (Approximation of functions of several real variables), written under the direction of Charles de la Vallée-Poussin.
The tragedy of the war in which he took part deeply marked him, although there is no evidence to suggest the reason he became a priest was due to traumas he suffered in combat; Lemaître had made it clear to his parents at an early age that he was interested in a vocation: he entered the Mechelen seminary and was ordained as a priest in 1923. Neither the war nor his studies nor his vocation dried up his curiosity: since 1920, he had learnt the theory of relativity and perfectly mastered it.
In 1923, he became a graduate student in astronomy at the University of Cambridge, spending one year at St Edmund's House (now St Edmund's College, Cambridge). He worked with the astronomer Arthur Eddington who initiated him into modern cosmology, stellar astronomy and numerical analysis. He spent the following year at Harvard College Observatory in Cambridge, Massachusetts with Harlow Shapley, who had just gained a name for his work on nebulae, and to the Massachusetts Institute of Technology, where he registered for the doctorate in sciences.
In 1925, on his return to Belgium, he became a part-time lecturer at the University of Leuven. He then began the report which would bring him international notoriety and which was published in 1927 in the Annales de la Société Scientifique de Bruxelles (Annals of the Scientific Society of Brussels), under the title 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 of extragalactic nebulae). In this report, he presented the new idea of an expanding Universe.
At this time, Einstein, whilst approving of the mathematics of Fr. Lemaître's theory, refused to accept the idea of an expanding universe. The same year, Lemaître returned to MIT to present his doctoral thesis on The gravitational field in a fluid sphere of uniform invariant density according to the theory of relativity. He obtained a PhD and was then named ordinary Professor at the University of Leuven.
In 1930, Eddington published an English translation of the 1927 article with a long commentary. Fr. Lemaître was then invited to London in order to take part in a meeting of the British Association on the relation between the physical Universe and spirituality. It is there that he proposed an expanding Universe which started with an initial singularity, and the idea of the Primeval Atom which he developed in a report published in the Monthly Notices of the Royal Astronomical Society. Fr. Lemaître himself liked to describe his theory as "the Cosmic Egg exploding at the moment of the creation", which was later to be coined by his critics as the Big Bang theory.
This proposal met skepticism from his fellow scientists at the time. Eddington found Fr. Lemaître's notion unpleasant. As for Einstein, he found it suspect, because, according to him, it was too strongly reminiscent of the Christian dogma of creation and was unjustifiable from a physical point of view. On the other hand, Einstein encouraged Lemaître to look into the possibility of non-isotropic expansion models, so it's clear he was not dismissive of the concept altogether. He also appreciated Lemaître's argument that a static-Einstein model of the universe could not be sustained indefinitely into the past.
In January 1933, Fr. Lemaître and Einstein, who had met on several occasions - in 1927 in Brussels, at the time of a Solvay Conference, in 1932 in Belgium, at the time of a cycle of conferences in Brussels and lastly in 1935 at Princeton - traveled together to California for a series of seminars. After the Belgian detailed his theory, Einstein stood up, applauded, and is supposed to have said, "This is the most beautiful and satisfactory explanation of creation to which I have ever listened". However there is disagreement over the reporting of this quote in the newspapers of the time and it is likely that Einstein was not actually referring to the theory as a whole--but in fact to Lemaître's proposal that cosmic rays might in fact be the left over artifacts of the initial 'explosion'. Later research on cosmic rays by Robert Millikan would undercut his proposal, however.
In 1933, when he resumed his theory of the expanding Universe and published a more detailed version in the Annals of the Scientific Society of Brussels, Fr. Lemaître would achieve his greatest glory. The American newspapers called him a famous Belgian scientist and described him as the leader of the new cosmological physics.
On March 17, 1934, Fr. Lemaître received the Francqui Prize, the highest Belgian scientific distinction, from King Léopold III. His proposers were Albert Einstein, Charles de la Vallée-Poussin and Alexandre de Hemptinne. The members of the international jury were Eddington, Langevin and Théophile de Donder. Another distinction that the Belgian government reserves for exceptional scientists was allotted to him in 1950: the decennial prize for applied sciences for the period 1933-1942.
In 1936, he was elected member of the Pontifical Academy of Sciences. He took an active role there, became the president in March 1960 and remaining so until his death. At the outset of the Second Vatican Council, he was bemused to find himself appointed by the Pope to sit on a commission investigating the subject of birth control. He was also named prelate (Monsignor) in 1960 by Pope John XXIII.
In 1941, he was elected member of the Royal Academy of Sciences and Arts of Belgium.
In 1946, he published his book on L'Hypothèse de l'Atome Primitif (The Primeval Atom Hypothesis), a book which would be translated into Spanish in the same year and into English in 1950.
In 1953 he was given the very first Eddington Medal award of the Royal Astronomical Society.
During the 1950s, he gradually gave up part of his teaching workload, ending it completely with his éméritat in 1964.
At the end of his life, he was devoted more and more to numerical calculation. He was in fact a remarkable algebraicist and arithmetical calculator. Since 1930, he used the most powerful calculating machines of the time like the Mercedes. In 1958, he introduced at the University a Burroughs E 101, the University's first electronic computer. Fr. Lemaître kept a strong interest in the development of computers and, even more, in the problems of language and programming. With age, this interest grew until it absorbed him almost completely.
He died on June 20, 1966 shortly after having learned of the discovery of cosmic microwave background radiation, proof of his intuitions about the birth of the Universe.
[edit] Personality
Sociable, devoted to his students and collaborators, he remained, however, an isolated researcher, and one finds only few correspondences and scientific exchanges with his peers.
If this undeniable co-founder of modern cosmology remains in the shade of the great names of the 20th century (Einstein, Eddington, Hubble and Gamow in particular), it may be due to the fact that scientists themselves are often remiss in keeping up with the history of their own discipline. It has been suggested that Lemaître's obscurity may have been due to anti-clerical bias. But the evidence for this is scant. Fred Hoyle, who coined the term Big Bang, in fact got along quite well with Lemaître and they enjoyed each other's company and respected each other's scientific work.
