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Georges Lemaître

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This article is about the Belgian physicist and priest. For the spacecraft, see Georges Lemaître ATV. For the American physician, see George D. LeMaitre. For the professional road bicycle racer, see Georges Lemaire.

The Reverend Monsignor
Georges Lemaître
RAS Associate
Lemaître in 1933
Born
Georges Henri Joseph Édouard Lemaître

(1894-07-17)17 July 1894
Charleroi, Belgium
Died20 June 1966(1966-06-20) (aged 71)
Leuven, Belgium
Alma materCatholic University of Louvain
St Edmund's House, Cambridge
Massachusetts Institute of Technology (MIT)
Known forTheory of the expansion of the universe
Big Bang theory
Hubble–Lemaître law
Lemaître–Tolman metric
Lemaître coordinates
Friedmann–Lemaître–Robertson–Walker metric
Cosmological constant
AwardsFrancqui Prize (1934), Eddington Medal (1953)
Scientific career
FieldsPhysical cosmology, Astrophysics, Mathematics
InstitutionsCatholic University of Leuven
Doctoral advisorCharles Jean de la Vallée-Poussin (Louvain), Paul Heymans (MIT)
Other academic advisorsArthur Eddington, Harlow Shapley
Ecclesiastical career
ReligionChristianity
ChurchCatholic Church
Ordained22 September 1923
by Désiré-Joseph Mercier
Signature
Part of a series on
Physical cosmology
Full-sky image derived from nine years' WMAP data
Early universe
Backgrounds
Expansion · Future
Components · Structure
Components
Structure
Experiments
Scientists
Subject history

Georges Henri Joseph Édouard Lemaître (/ləˈmɛtrə/ lə-MET-rə; French: [ʒɔʁʒ ləmɛːtʁ] ⓘ; 17 July 1894 – 20 June 1966) was a Belgian Catholic priest, theoretical physicist, and mathematician who made major contributions to cosmology and astrophysics.[1] He was the first to argue that the recession of galaxies is evidence of an expanding universe and to connect the observational Hubble–Lemaître law[2] with the solution to the Einstein field equations in the general theory of relativity for a homogenous and isotropic universe.[3][4][5] That work led Lemaître to propose what he called the "hypothesis of the primeval atom", now regarded as the first formulation of the Big Bang theory of the origin of the universe.[6][7]

Lemaître was a professor of physics at the Catholic University of Louvain from 1927 until his retirement in 1964. With Manuel Sandoval Vallarta, he showed in the 1930s that cosmic rays are deflected by the Earth's magnetic field and must therefore carry electric charge. Lemaître was a pioneer in the use of computers in physics research. In 1960, Pope John XXIII appointed him Domestic Prelate, entitling him to be addressed as "Monsignor". In that same year he became president of the Pontifical Academy of Sciences, a post that he occupied until his death.[8]

Early life

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Lemaître was born in Charleroi, Belgium, the eldest of four children. His father Joseph Lemaître was a prosperous industrial weaver and his mother was Marguerite, née Lannoy.[9] After a classical education at a Jesuit secondary school, the Collège du Sacré-Cœur, in Charleroi, he began studying civil engineering at the Catholic University of Louvain at the age of 17. In 1914, he interrupted his studies to serve as an artillery officer in the Belgian army during World War I. At the end of hostilities he received the Belgian War Cross with palms.[10]

After the war, he studied physics and mathematics. He considered joining the Jesuits, but finally decided to prepare instead for the diocesan priesthood.[11] He obtained his doctorate in 1920 with a thesis entitled L'approximation des fonctions de plusieurs variables réelles ("The approximation of functions of several real variables"), written under the direction of the mathematician Charles de la Vallée-Poussin.[12] He was ordained as a priest on 22 September 1923 by Cardinal Désiré-Joseph Mercier, the Archbishop of Mechelen.[13][14] As a diocesan priest in French-speaking Belgium, he was known as "Abbé Lemaître".

The church authorities allowed Lemaître to continue his scientific work. Only ten days after his ordination, Lemaître travelled to England, taking up residence in St Edmund's House, then a community of Catholic priests studying for degrees at the University of Cambridge and which would later become St Edmund's College. At Cambridge, Lemaître was a research associate in astronomy and worked with the eminent astrophysicist Arthur Eddington, who introduced Lemaître to modern cosmology, stellar astronomy, and numerical analysis.[15][16] Lemaître then spent the following year at the Harvard College Observatory, in Cambridge, Massachusetts, working with Harlow Shapley, a leading expert in the study of what were then called "spiral nebulae" (now identified as spiral galaxies). Lemaître also registered at that time in the doctoral program in science at the Massachusetts Institute of Technology (MIT), with the Belgian engineer Paul Heymans as his official advisor.

Work on cosmology

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On his return to Belgium in 1925, Lemaître became a part-time lecturer at the Catholic University of Louvain and began working on a report that was finally 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").[3] There he developed (independently of the earlier work of Alexander Friedmann) the argument that the equations of the general theory of relativity implied that the Universe is not static (see Friedmann equations). Lemaître connected this prediction to what he argued was a simple relation of proportionality between the average recessional velocity of galaxies and their distance to the Earth. The initial state that Lemaître proposed for the Universe was Einstein's model of a static universe with a cosmological constant.[17]

Lemaître's 1927 report had little impact because the journal in which it was published was not widely read by astronomers or physicists outside Belgium. Also in 1927, Lemaître returned to MIT to defend his doctoral dissertation on The gravitational field in a fluid sphere of uniform invariant density according to the theory of relativity.[18] Upon obtaining this second doctorate, Lemaître's was appointed ordinary professor at the Catholic University of Louvain. At this time, Einstein, while not taking exception to the mathematics of Lemaître's theory, refused to accept that the universe was expanding; Lemaître later recalled his commenting "Vos calculs sont corrects, mais votre physique est abominable" ("Your calculations are correct, but your physics is atrocious").[19]

In 1929, the US astronomer Edwin Hubble published a paper in the Proceedings of the National Academy of Sciences of the United States of America in which, based on better and more abundant data than what Lemaître had had at his disposal in 1927, Hubble found that, in the average, galaxies recede at a velocity proportional their distance from the observer. Hubble did not cite Lemaître's prior work, of which he apparently was unaware at the time. Although Hubble himself did not interpret that result as evidence of an expanding Universe, his work attracted widespread attention and eventually convinced many experts, including Einstein, that the Universe is not static. The proportionality between distance and recessional velocity for galaxies has since been commonly known as "Hubble's law", but in 2018 the International Astronomical Union (IAU) adopted a resolution recommending that it be referred to as the "Hubble-Lemaître law".[2]

According to the Big Bang theory, the universe emerged from an extremely dense and hot state (singularity). Space itself has been expanding ever since, carrying galaxies with it, like raisins in a rising loaf of bread. The graphic scheme above is an artist's conception illustrating the expansion of a portion of a flat universe.

In 1931, an English translation of Lemaître's 1927 report was published in the Monthly Notices of the Royal Astronomical Society, with a commentary by Arthur Eddington that characterized Lemaître's work as a "brilliant solution" to the outstanding problems of cosmology and a response by Lemaître to Eddington's comments.[20] This English translation, however, omitted Lemaître's estimation of the "Hubble constant" for reasons that remained unclear for many years.[21] The issue was clarified in 2011 by Mario Livio: Lemaître himself removed those paragraphs when he prepared the English translation, opting instead to cite the stronger results that Hubble had published in 1929.[5]

Following the publication of his work in English, Lemaître was invited to participate in a meeting of the British Association for the Advancement of Science on the relation between the physical universe and spirituality. There Lemaître proposed that the universe expanded from an initial quantum, which he called the "primeval atom". He developed this idea in a brief report published that same year in Nature.[6] Lemaître's theory appeared for the first time in an article for a general audience in the December 1932 issue of Popular Science.[22] Lemaître's theory later became known as the "Big Bang theory," a term coined derisively by the astronomer Fred Hoyle in a 1949 BBC radio broadcast.[23][24] Hoyle remained throughout his life an opponent of cosmological theories in which the Universe has a beginning in time, advocating instead a steady-state model of an eternal Universe.

Lemaître and Einstein met on four 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; in California in January 1933;[25] and in 1935 at Princeton. In 1933 at the California Institute of Technology, after Lemaître 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."[26] However, there is disagreement over the reporting of this quote in the newspapers of the time, and it may be that Einstein was not referring to the theory as a whole, but only to Lemaître's proposal that cosmic rays may be the leftover artifacts of the initial "explosion".

Robert Millikan, Lemaître and Albert Einstein after Lemaître's lecture at the California Institute of Technology in January 1933.

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, Lemaître achieved his greatest public recognition.[27] Newspapers around the world called him a famous Belgian scientist and described him as the leader of new cosmological physics. Also in 1933, Lemaître served as a visiting professor at The Catholic University of America.[28] In 1946, he published his book on L'Hypothèse de l'Atome Primitif ("The Primeval Atom Hypothesis"), which was translated into Spanish in the same year and into English in 1950.

Lemaître viewed his work as a scientist as neither supporting nor contradicting any truths of the Catholic faith, and he was strongly opposed to making any arguments that mixed science with religion,[14] although he held that the two were not in conflict.[29] In 1951, Pope Pius XII gave a speech before the Pontifical Academy of Sciences, with Lemaître in the audience, drawing a parallel between the new Big Bang cosmology and the traditional Christian doctrine of creatio ex nihilo. Lemaître was reportedly horrified by that intervention and was later able to convince the Pope not make further public statements on religious interpretations of scientific matters concerning physical cosmology.[15]

Lemaître and Eddington in discussion when sailing back from the 6th GA of the International Astronomical Union held in Stockholm in 1938

Other scientific work

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With Manuel Sandoval Vallarta, whom he had met at MIT, Lemaître showed that the intensity of cosmic rays varies with latitude because they are composed on charged particles and therefore are deflected by the Earth's magnetic field.[30] In their calculations, Lemaître and Vallarta made use of MIT's differential analyzer computer, developed by Vannevar Bush. That work disproved the view, advocated among others by the Nobel laureate Robert Millikan, that cosmic rays were composed of high-energy photons. Lemaître and Vallarta also worked on a theory of primary cosmic radiation and applied it to their investigations of the Sun's magnetic field and the effects of the galaxy's rotation.

In 1933, Lemaître found an important inhomogeneous solution of Einstein's field equations describing a spherical dust cloud, the Lemaître–Tolman metric. In his later years Lemaître became increasingly devoted to problems of numerical calculation. He was a remarkable algebraicist and arithmetical calculator. Since 1930, he had used the most powerful calculating machine of the time, the Mercedes-Euklid. In 1958, he was introduced to the University's Burroughs E 101, its first electronic computer. Lemaître maintained a strong interest in the development of computers and, even more, in problems of language and computer programming.

In 1948 Lemaître published a mathematical essay titled Quaternions et espace elliptique ("Quaternions and elliptic space").[31] William Kingdon Clifford had introduced the concept of elliptic space in 1873. Lemaître developed the theory of quaternions from first principles, in the spirit of the Erlangen program.[citation needed]

Final years

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During the 1950s, Lemaître gradually gave up part of his teaching workload, ending it completely when he took emeritus status in 1964. In 1960 he was named domestic prelate (with the treatment of "Monsignor") by Pope John XXIII.[32] In 1962, strongly opposed to the expulsion of French speakers from the Catholic University of Louvain, Lemaître created the ACAPSUL movement together with Gérard Garitte to fight against the split.[33]

During the Second Vatican Council of 1962–65, the pope asked Lemaître to serve on the 4th session of the Pontifical Commission on Birth Control.[34] However, since his health made it impossible for him to travel to Rome —he suffered a heart attack in December 1964— Lemaître demurred. He told a Dominican colleague, Père Henri de Riedmatten, that he thought it was dangerous for a mathematician to venture outside of his area of expertise.[35] Lemaître died on 20 June 1966, shortly after having learned of the discovery of cosmic microwave background radiation, which provided solid experimental support for his theory of the Big Bang.[36]

Honours and recognition

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On July 27, 1935, Lemaître was appointed as an honorary canon of St. Rumbold's Cathedral by Cardinal Jozef-Ernest van Roey.[37] He was elected a member of the Pontifical Academy of Sciences in 1936, and took an active role there, serving as its president from March 1960 until his death.[38] In 1941, he was elected a member of the Royal Academy of Sciences and Arts of Belgium.[32]

On 17 March 1934, Lemaître received the Francqui Prize, the highest Belgian scientific distinction, from King Leopold III.[32] His proposers were Albert Einstein, Charles de la Vallée-Poussin and Alexandre de Hemptinne. The members of the international jury were Eddington, Langevin, Théophile de Donder and Marcel Dehalu. The same year he received the Mendel Medal of the Villanova University.[39]

In 1936, Lemaître received the Prix Jules Janssen, the highest award of the Société astronomique de France, the French astronomical society.[40] 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.[32] Lemaître was elected to the American Philosophical Society in 1945.[41] In 1953, he was given the inaugural Eddington Medal by the Royal Astronomical Society.[42][43]

In 2005, Lemaître was voted to the 61st place of De Grootste Belg ("The Greatest Belgian"), a Flemish television program on the VRT. In the same year he was voted to the 78th place by the audience of the Les plus grands Belges ("The Greatest Belgians"), a television show of the RTBF. Later, in December 2022, VRT recovered in its archives a lost 20-minute interview with Georges Lemaître in 1964, "a gem," says cosmologist Thomas Hertog.[44][45] On 17 July 2018, Google Doodle celebrated Georges Lemaître's 124th birthday.[46] On 26 October 2018, an electronic vote among all members of the International Astronomical Union voted 78% to recommend changing the name of the Hubble law to the Hubble–Lemaître law.[2][47]

Namesakes

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Bibliography

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"L'Hypothèse de l'Atome primitif" (The Primeval Atom – an Essay on Cosmogony) (1946)

References

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  1. ^ "Obituary: Georges Lemaitre". Physics Today. 19 (9): 119–121. September 1966. doi:10.1063/1.3048455.
  2. ^ a b c "name change for Hubble Law". Nature. 563 (7729): 10–11. 31 October 2018. doi:10.1038/d41586-018-07180-9. PMID 30382217. S2CID 256770198. The International Astronomical Union recommends that the law should now be known as the Hubble–Lemaître law, to pay tribute to the Belgian priest and astronomer Georges Lemaître, who derived the speed–distance relationship two years earlier than did US astronomer Edwin Hubble.
  3. ^ a b Lemaître 1927a, p. 49.
  4. ^ Reich 2011.
  5. ^ a b Livio 2011, pp. 171–173.
  6. ^ a b Lemaître 1931b, p. 706.
  7. ^ "Big bang theory is introduced – 1927". A Science Odyssey. WGBH. Retrieved 31 July 2014.
  8. ^ "Georges Lemaitre". Pontifical Academy of Science. Archived from the original on 19 October 2021. Retrieved 4 September 2018.
  9. ^ Dominique Lambert, An Atom of the Universe: The Life and Work of Georges Lemaître, Lessius, 2000, p.22
  10. ^ "Croix de guerre, reçue en 1918 et la palme en 1921 (Georges Lemaître)". archives.uclouvain.be. Retrieved 7 September 2018.
  11. ^ Farrell 2008.
  12. ^ "Georges Lemaître - the Mathematics Genealogy Project".
  13. ^ Lambert 1996, pp. 309–343.
  14. ^ a b Lambert 1997, pp. 28–53.
  15. ^ a b Holder, Rodney D.; Mitton, Simon (13 January 2013). Georges Lemaître: Life, Science and Legacy. Springer. ISBN 9783642322549.
  16. ^ General Relativity Conflict and Rivalries: Einstein's Polemics with Physicists. Cambridge Scholars. 14 January 2016. ISBN 9781443887809.
  17. ^ Belenkiy 2012, p. 38.
  18. ^ Lemaître 1927b.
  19. ^ Deprit 1984, p. 370.
  20. ^ Lemaître 1931a, pp. 490–501.
  21. ^ Way & Nussbaumer 2011, p. 8.
  22. ^ Menzel 1932, p. 52.
  23. ^ "Third Programme – 28 March 1949". BBC Genome. Retrieved 4 September 2018.
  24. ^ "Hoyle on the Radio: Creating the 'Big Bang'". Fred Hoyle: An Online Exhibition. St John's College Cambridge. Retrieved 4 September 2018.
  25. ^ Lambert n.d.
  26. ^ Kragh 1999, p. 55.
  27. ^ Lemaître 1934, pp. 12–17.
  28. ^ McCarthy Hines, Mary. "Physics Professor Earns Historic Recognition". Catholic U (Spring 2019). The Catholic University of America: 16.
  29. ^ Crawley, William. 2012. "Father of the Big Bang". BBC.
  30. ^ Lemaitre, G.; Vallarta, M. S. (15 January 1933). "On Compton's Latitude Effect of Cosmic Radiation". Physical Review. 43 (2): 87–91. Bibcode:1933PhRv...43...87L. doi:10.1103/PhysRev.43.87. S2CID 7293355.
  31. ^ Lemaître G., "Quaternions et espace elliptique, (note présentée lors de la séance du 8 février 1948)", Acta Pontificiae Academiae Scientiarum, 1948, 12(8), pp. 57-78
  32. ^ a b c d "Rapport Jury Mgr Georges Lemaître". Fondation Francqui – Stichting (in French). 1934. Retrieved 4 September 2018.
  33. ^ "ACAPSUL – Association du corps académique et du personnel scientifique de l'Université de Louvain".
  34. ^ McClory 1998, p. 205.
  35. ^ Lambert 2000, p. 302.
  36. ^ "Georges Lemaître: Who was the Belgian priest who discovered the universe is expanding?". Independent.co.uk. 16 July 2018.
  37. ^ "The Faith and Reason of Father George Lemaître". catholicculture.org. February 2009. Retrieved 3 January 2021.
  38. ^ "Georges Lemaitre". Pontifical Academy of Science. Archived from the original on 19 October 2021. Retrieved 4 September 2018.
  39. ^ "Abbé Georges Edouard Etienne Lemaître, Ph.D., D.Sc. – 1934". Villanova University. Retrieved 5 September 2018.
  40. ^ "Médaille du prix Janssen décernée par la Société Astronomique de France à Georges Lemaître (1936)". Archives.uclouvain.be. Retrieved 7 September 2018.
  41. ^ "APS Member History". search.amphilsoc.org. Retrieved 27 March 2023.
  42. ^ "Medallists of the Royal Astronomical Society". Archived from the original on 16 July 2011. Retrieved 13 June 2012.
  43. ^ Monthly Notices of the Royal Astronomical Society, Vol. 113, p.2
  44. ^ De Maeseneer, Wim (31 December 2022). "Lang naar gezocht, eindelijk gevonden: VRT vindt interview uit 1964 terug met de Belg die de oerknal bedacht" [Long sought, finally found: VRT finds 1964 interview with Belgian who invented the Big Bang]. vrtnws.be (in Dutch). Retrieved 4 January 2023. VRT has recovered a lost interview with Georges Lemaître in its archives. He was interviewed about it in 1964 for the then BRT, but until recently it was thought that only a short excerpt of it had been preserved. Now the entire 20-minute interview has been recovered. "A gem," says cosmologist Thomas Hertog.
  45. ^ Satya Gontcho A Gontcho; Jean-Baptiste Kikwaya Eluo; Gabor, Paul (2023). "Resurfaced 1964 VRT video interview of Georges Lemaître". arXiv:2301.07198 [physics.hist-ph].
  46. ^ "Who was Georges Lemaître? Google Doodle celebrates 124th birthday of the astronomer behind the Big Bang Theory". Daily Mirror. 17 July 2018.
  47. ^ Gibney 2018.

Sources

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Further reading

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