Georges Lemaître

Georges Lemaître

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Monsignor Georges Henri Joseph Édouard Lemaître ( 17 July 1894 – 20 June 1966) was a Belgian
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

 priest
Priest
A priest is a person authorized to perform the sacred rites of a religion, especially as a mediatory agent between humans and deities. They also have the authority or power to administer religious rites; in particular, rites of sacrifice to, and propitiation of, a deity or deities...

, astronomer
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

 and professor of physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 at the Catholic University of Louvain
Catholic University of Leuven
The Catholic University of Leuven, or of Louvain, was the largest, oldest and most prominent university in Belgium. The university was founded in 1425 as the University of Leuven by John IV, Duke of Brabant and approved by a Papal bull by Pope Martin V.During France's occupation of Belgium in the...

. He was the first person to propose the theory of the expansion of the Universe
Metric expansion of space
The metric expansion of space is the increase of distance between distant parts of the universe with time. It is an intrinsic expansion—that is, it is defined by the relative separation of parts of the universe and not by motion "outward" into preexisting space...

, widely misattributed to Edwin Hubble
Edwin Hubble
Edwin Powell Hubble was an American astronomer who profoundly changed the understanding of the universe by confirming the existence of galaxies other than the Milky Way - our own galaxy...

. He was also the first to derive what is now known as the Hubble's law
Hubble's law
Hubble's law is the name for the astronomical observation in physical cosmology that: all objects observed in deep space are found to have a doppler shift observable relative velocity to Earth, and to each other; and that this doppler-shift-measured velocity, of various galaxies receding from...

 and made the first estimation of what is now called the Hubble constant which he published in 1927, two years before Hubble's article
.
Lemaître also proposed what became known as the Big Bang
Big Bang
The Big Bang theory is the prevailing cosmological model that explains the early development of the Universe. According to the Big Bang theory, the Universe was once in an extremely hot and dense state which expanded rapidly. This rapid expansion caused the young Universe to cool and resulted in...

 theory of the origin of the Universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...

, which he called his 'hypothesis of the primeval atom'.
He sometimes used the title Abbé
Abbé
Abbé is the French word for abbot. It is the title for lower-ranking Catholic clergymen in France....

or Monseigneur
Monsignor
Monsignor, pl. monsignori, is the form of address for those members of the clergy of the Catholic Church holding certain ecclesiastical honorific titles. Monsignor is the apocopic form of the Italian monsignore, from the French mon seigneur, meaning "my lord"...

.

Biography



After a classical education at a Jesuit
Society of Jesus
The Society of Jesus is a Catholic male religious order that follows the teachings of the Catholic Church. The members are called Jesuits, and are also known colloquially as "God's Army" and as "The Company," these being references to founder Ignatius of Loyola's military background and a...

 secondary school (Collège du Sacré-Coeur, Charleroi
Charleroi
Charleroi is a city and a municipality of Wallonia, located in the province of Hainaut, Belgium. , the total population of Charleroi was 201,593. The metropolitan area, including the outer commuter zone, covers an area of and had a total population of 522,522 as of 1 January 2008, ranking it as...

), Lemaître began studying civil engineering
Civil engineering
Civil engineering is a professional engineering discipline that deals with the design, construction, and maintenance of the physical and naturally built environment, including works like roads, bridges, canals, dams, and buildings...

 at the Catholic University of Louvain
Catholic University of Leuven
The Catholic University of Leuven, or of Louvain, was the largest, oldest and most prominent university in Belgium. The university was founded in 1425 as the University of Leuven by John IV, Duke of Brabant and approved by a Papal bull by Pope Martin V.During France's occupation of Belgium in the...

 at the age of 17. In 1914, he interrupted his studies to serve as an artillery officer in the Belgian army for the duration of World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

. At the end of hostilities, he received the Belgian Croix de Guerre
War Cross (Belgium)
The Belgian War Cross , established on 25 October 1915 is a military decoration of the Kingdom of Belgium. Presented primarily as an award for bravery or other military virtue on the battlefield. The award was reestablished on 20 July 1940, by the Belgian Government in exile in London, for...

 with palms.

After the war, he studied physics
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...

 and mathematics
Mathematics
Mathematics is the study of quantity, space, structure, and change. Mathematicians seek out patterns and formulate new conjectures. Mathematicians resolve the truth or falsity of conjectures by mathematical proofs, which are arguments sufficient to convince other mathematicians of their validity...

, and began to prepare for priest
Priest
A priest is a person authorized to perform the sacred rites of a religion, especially as a mediatory agent between humans and deities. They also have the authority or power to administer religious rites; in particular, rites of sacrifice to, and propitiation of, a deity or deities...

hood. He obtained his doctorate
Doctor of Philosophy
Doctor of Philosophy, abbreviated as Ph.D., PhD, D.Phil., or DPhil , in English-speaking countries, is a postgraduate academic degree awarded by universities...

 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. He was ordained
Ordination
In general religious use, ordination is the process by which individuals are consecrated, that is, set apart as clergy to perform various religious rites and ceremonies. The process and ceremonies of ordination itself varies by religion and denomination. One who is in preparation for, or who is...

 a priest
Priesthood (Catholic Church)
The ministerial orders of the Catholic Church include the orders of bishops, deacons and presbyters, which in Latin is sacerdos. The ordained priesthood and common priesthood are different in function and essence....

 in 1923.

In 1923, he became a graduate student in astronomy at the University of Cambridge
University of Cambridge
The University of Cambridge is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in both the United Kingdom and the English-speaking world , and the seventh-oldest globally...

, spending a year at St Edmund's House (now St Edmund's College, Cambridge
St Edmund's College, Cambridge
Saint Edmund's College is a constituent college of the University of Cambridge. It is the second oldest of the four Cambridge colleges oriented to mature students, which only accept students reading for either Masters or Doctorate degrees, or undergraduate degrees if they are aged 21 or older, the...

). He worked with Arthur Eddington who initiated him into modern cosmology
Cosmology
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

, stellar astronomy, and numerical analysis
Numerical analysis
Numerical analysis is the study of algorithms that use numerical approximation for the problems of mathematical analysis ....

. He spent the following year at Harvard College Observatory
Harvard College Observatory
The Harvard College Observatory is an institution managing a complex of buildings and multiple instruments used for astronomical research by the Harvard University Department of Astronomy. It is located in Cambridge, Massachusetts, USA, and was founded in 1839...

 in Cambridge, Massachusetts
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...

 with Harlow Shapley
Harlow Shapley
Harlow Shapley was an American astronomer.-Career:He was born on a farm in Nashville, Missouri, and dropped out of school with only the equivalent of a fifth-grade education...

, who had just gained a name for his work on nebula
Nebula
A nebula is an interstellar cloud of dust, hydrogen gas, helium gas and other ionized gases...

e, and at the Massachusetts Institute of Technology
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...

, where he registered for the doctorate in sciences.

In 1925, on his return to Belgium, he became a part-time lecturer at the Catholic University of Louvain. He then began the report which would bring him international fame, 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 his new idea of an expanding Universe (he also derived Hubble's law
Hubble's law
Hubble's law is the name for the astronomical observation in physical cosmology that: all objects observed in deep space are found to have a doppler shift observable relative velocity to Earth, and to each other; and that this doppler-shift-measured velocity, of various galaxies receding from...

 and provided the first observational estimation of the Hubble constant) but not yet that of the primeval atom. Instead, the initial state was taken as Einstein's own finite-size static universe model. Unfortunately, the paper had little impact because the journal in which it was published was not widely read by astronomers outside of Belgium.

At this time, Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

, while not taking exception to the mathematics of Lemaître's theory, refused to accept the idea of an expanding universe; Lemaître recalled him commenting "" ("Your math is correct, but your physics is abominable.") 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. Upon obtaining the PhD, he was named Ordinary Professor at the Catholic University of Louvain.

In 1930, Eddington published in the Monthly Notices of the Royal Astronomical Society
Monthly Notices of the Royal Astronomical Society
Monthly Notices of the Royal Astronomical Society is one of the world's leading scientific journals in astronomy and astrophysics. It has been in continuous existence since 1827 and publishes peer-reviewed letters and papers reporting original research in relevant fields...

a long commentary on Lemaître's 1927 article, in which he described the latter as a "brilliant solution" to the outstanding problems of cosmology. The original paper was published in an abbreviated English translation in 1931, along with a sequel by Lemaître responding to Eddington's comments. Lemaître was then invited to London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 in order to take part in a meeting of the British Association
British Association for the Advancement of Science
frame|right|"The BA" logoThe British Association for the Advancement of Science or the British Science Association, formerly known as the BA, is a learned society with the object of promoting science, directing general attention to scientific matters, and facilitating interaction between...

 on the relation between the physical Universe and spirituality. There he proposed that the Universe expanded from an initial point, which he called the "Primeval Atom" and developed in a report published in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

. Lemaître himself also described his theory as "the Cosmic Egg exploding at the moment of the creation"; it became better known as the "Big Bang theory," a term coined by Fred Hoyle
Fred Hoyle
Sir Fred Hoyle FRS was an English astronomer and mathematician noted primarily for his contribution to the theory of stellar nucleosynthesis and his often controversial stance on other cosmological and scientific matters—in particular his rejection of the "Big Bang" theory, a term originally...

.

This proposal met skepticism
Skepticism
Skepticism has many definitions, but generally refers to any questioning attitude towards knowledge, facts, or opinions/beliefs stated as facts, or doubt regarding claims that are taken for granted elsewhere...

 from his fellow scientists at the time. Eddington found Lemaître's notion unpleasant. Einstein found it suspect because he deemed it unjustifiable from a physical point of view. On the other hand, Einstein encouraged Lemaître to look into the possibility of models of non-isotropic expansion, so it's clear he was not altogether dismissive of the concept. 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, Lemaître and Einstein, who had met on several occasions - in 1927 in Brussels
Brussels
Brussels , officially the Brussels Region or Brussels-Capital Region , is the capital of Belgium and the de facto capital of the European Union...

, at the time of a Solvay Conference
Solvay Conference
The International Solvay Institutes for Physics and Chemistry, located in Brussels, were founded by the Belgian industrialist Ernest Solvay in 1912, following the historic invitation-only 1911 Conseil Solvay, the turning point in world physics...

, in 1932 in Belgium, at the time of a cycle of conferences in Brussels and lastly in 1935 at Princeton
Princeton University
Princeton University is a private research university located in Princeton, New Jersey, United States. The school is one of the eight universities of the Ivy League, and is one of the nine Colonial Colleges founded before the American Revolution....

 - 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 may be that Einstein was not actually referring to the theory as a whole but to Lemaître's proposal that cosmic ray
Cosmic ray
Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...

s may in fact be the left over artifacts of the initial "explosion." Later research on cosmic rays by Robert Millikan
Robert Millikan
Robert A. Millikan was an American experimental physicist, and Nobel laureate in physics for his measurement of the charge on the electron and for his work on the photoelectric effect. He served as president of Caltech from 1921 to 1945...

 would undercut this 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, Lemaître would achieve his greatest glory. Newspapers around the world called him a famous Belgian scientist and described him as the leader of the new cosmological physics.

On 17 March 1934, Lemaître received the Francqui Prize
Francqui Prize
The Francqui Prize is a prestigious Belgian scholarly and scientific prize, awarded each year since 1933 by the Francqui Foundation in recognition of the achievements of a young Belgian scholar or scientist...

, the highest Belgian scientific distinction, from King Léopold III
Leopold III of Belgium
Leopold III reigned as King of the Belgians from 1934 until 1951, when he abdicated in favour of the Heir Apparent,...

. His proposers were Albert Einstein, Charles de la Vallée-Poussin and Alexandre de Hemptinne. The members of the international jury were Eddington, Langevin
Paul Langevin
Paul Langevin was a prominent French physicist who developed Langevin dynamics and the Langevin equation. He was one of the founders of the Comité de vigilance des intellectuels antifascistes, an antifascist organization created in the wake of the 6 February 1934 far right riots...

 and Théophile de Donder
Théophile de Donder
Théophile Ernest de Donder was a Belgian mathematician and physicist famous for his 1923 work in developing correlations between the Newtonian concept of chemical affinity and the Gibbsian concept of free energy.-Education:...

. 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
Pontifical Academy of Sciences
The Pontifical Academy of Sciences is a scientific academy of the Vatican, founded in 1936 by Pope Pius XI. It is placed under the protection of the reigning Supreme Pontiff. Its aim is to promote the progress of the mathematical, physical and natural sciences and the study of related...

.
He took an active role there, becoming its president in March 1960 and remaining so until his death. During Vatican II he was asked to serve on the first special commission to examine the question of contraception. However, as he could not travel to Rome because of his health (he had suffered a heart attack in December 1964), Lemaître demurred, expressing his surprise that he was even chosen, at the time telling a Dominican colleague, P. Henri de Riedmatten, that he thought it was dangerous for a mathematician to venture outside of his speciality. He was also named prelate
Prelate
A prelate is a high-ranking member of the clergy who is an ordinary or who ranks in precedence with ordinaries. The word derives from the Latin prælatus, the past participle of præferre, which means "carry before", "be set above or over" or "prefer"; hence, a prelate is one set over others.-Related...

 (Monsignor
Monsignor
Monsignor, pl. monsignori, is the form of address for those members of the clergy of the Catholic Church holding certain ecclesiastical honorific titles. Monsignor is the apocopic form of the Italian monsignore, from the French mon seigneur, meaning "my lord"...

) in 1960 by Pope John XXIII
Pope John XXIII
-Papal election:Following the death of Pope Pius XII in 1958, Roncalli was elected Pope, to his great surprise. He had even arrived in the Vatican with a return train ticket to Venice. Many had considered Giovanni Battista Montini, Archbishop of Milan, a possible candidate, but, although archbishop...

.

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). It would be translated into Spanish in the same year and into English in 1950.

In 1953, he was given the very first Eddington Medal
Eddington Medal
The Eddington Medal, named after Sir Arthur Eddington, is awarded by the Royal Astronomical Society nominally once every two years for investigations of outstanding merit in theoretical astrophysics.- Recipients :* 1953 Georges Lemaître...

 awarded by the Royal Astronomical Society
Royal Astronomical Society
The Royal Astronomical Society is a learned society that began as the Astronomical Society of London in 1820 to support astronomical research . It became the Royal Astronomical Society in 1831 on receiving its Royal Charter from William IV...

.

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, the Mercedes
Mercedes (calculator)
The Mercedes-Euklid is a German-invented calculator from the early twentieth century. It was built in Thuringia, Germany in 1905. The first manual mechanical models utilized a proportional-lever design invented by Christel Hamann in 1903....

. 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 the problems of language
Language
Language may refer either to the specifically human capacity for acquiring and using complex systems of communication, or to a specific instance of such a system of complex communication...

 and programming. Throughout his latter years these were abiding interests until they absorbed him almost completely.

He died on 20 June 1966, shortly after having learned of the discovery of cosmic microwave background radiation
Cosmic microwave background radiation
In cosmology, cosmic microwave background radiation is thermal radiation filling the observable universe almost uniformly....

, which provided further evidence for his intuitions about the birth of the Universe.

In 2005, Lemaître was voted to the 61st place of (Dutch
Dutch language
Dutch is a West Germanic language and the native language of the majority of the population of the Netherlands, Belgium, and Suriname, the three member states of the Dutch Language Union. Most speakers live in the European Union, where it is a first language for about 23 million and a second...

 for "The Greatest Belgian"), a Flemish
Flanders
Flanders is the community of the Flemings but also one of the institutions in Belgium, and a geographical region located in parts of present-day Belgium, France and the Netherlands. "Flanders" can also refer to the northern part of Belgium that contains Brussels, Bruges, Ghent and Antwerp...

 television program on the VRT
VRT
The abbreviation VRT may be a reference to:* Vehicle Registration Tax* Verkehrsverbund Region Trier, Trier regional transport* Vision Restoration Therapy, a therapy to improve the visual field after a stroke or brain injury...

. In the same year he was voted to the 78th place by the audience of the (French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...

 for "The Greatest Belgian"), a television show of the RTBF
RTBF
Radio Télévision Belge Francophone is the public broadcasting organization of the French Community of Belgium, the southern, French-speaking part of Belgium...

.

Work


Lemaître was a pioneer in applying Albert Einstein
Albert Einstein
Albert Einstein was a German-born theoretical physicist who developed the theory of general relativity, effecting a revolution in physics. For this achievement, Einstein is often regarded as the father of modern physics and one of the most prolific intellects in human history...

's theory of general relativity
General relativity
General relativity or the general theory of relativity is the geometric theory of gravitation published by Albert Einstein in 1916. It is the current description of gravitation in modern physics...

 to cosmology
Cosmology
Cosmology is the discipline that deals with the nature of the Universe as a whole. Cosmologists seek to understand the origin, evolution, structure, and ultimate fate of the Universe at large, as well as the natural laws that keep it in order...

. In a 1927 article, which preceded Edwin Hubble
Edwin Hubble
Edwin Powell Hubble was an American astronomer who profoundly changed the understanding of the universe by confirming the existence of galaxies other than the Milky Way - our own galaxy...

's landmark article by two years, Lemaître derived what became known as Hubble's law
Hubble's law
Hubble's law is the name for the astronomical observation in physical cosmology that: all objects observed in deep space are found to have a doppler shift observable relative velocity to Earth, and to each other; and that this doppler-shift-measured velocity, of various galaxies receding from...

 and proposed it as a generic phenomenon in relativistic cosmology. Lemaître also estimated the numerical value of the Hubble constant. However, the data used by Lemaître did not allow him to prove that there was an actual linear relation, which Hubble did two years later.

Einstein was skeptical of this paper. When Lemaître approached Einstein at the 1927 Solvay Conference
Solvay Conference
The International Solvay Institutes for Physics and Chemistry, located in Brussels, were founded by the Belgian industrialist Ernest Solvay in 1912, following the historic invitation-only 1911 Conseil Solvay, the turning point in world physics...

, the latter pointed out that Alexander Friedmann had proposed a similar solution to Einstein's equations in 1922, implying that the radius of the universe increased over time. (Einstein had also criticized Friedmann's calculations, but withdrew his comments.) In 1931, Lemaître published an article in Nature
Nature (journal)
Nature, first published on 4 November 1869, is ranked the world's most cited interdisciplinary scientific journal by the Science Edition of the 2010 Journal Citation Reports...

setting out his theory of the "primeval atom."

Friedmann was handicapped by living and working in the USSR
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

, and died in 1925, soon after inventing the Friedmann-Lemaître-Robertson-Walker metric. Because Lemaître spent his entire career in Europe, his scientific work is not as well known in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 as that of Hubble or Einstein, both well known in the U.S. by virtue of residing there. Nevertheless, Lemaître's theory changed the course of cosmology. This was because Lemaître:
  • Was well acquainted with the work of astronomers, and designed his theory to have testable implications and to be in accord with observations of the time, in particular, to explain the observed redshift
    Redshift
    In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...

     of galaxies and the linear relation between distances and velocities;
  • Proposed his theory at an opportune time, since Edwin Hubble
    Edwin Hubble
    Edwin Powell Hubble was an American astronomer who profoundly changed the understanding of the universe by confirming the existence of galaxies other than the Milky Way - our own galaxy...

     would soon publish his velocity-distance relation
    Hubble's law
    Hubble's law is the name for the astronomical observation in physical cosmology that: all objects observed in deep space are found to have a doppler shift observable relative velocity to Earth, and to each other; and that this doppler-shift-measured velocity, of various galaxies receding from...

     that strongly supported an expanding universe
    Metric expansion of space
    The metric expansion of space is the increase of distance between distant parts of the universe with time. It is an intrinsic expansion—that is, it is defined by the relative separation of parts of the universe and not by motion "outward" into preexisting space...

     and, consequently, the Big Bang theory;
  • Had studied under Arthur Eddington, who made sure that Lemaître got a hearing in the scientific community.


Both Friedmann and Lemaître proposed relativistic cosmologies featuring an expanding universe. However, Lemaître was the first to propose that the expansion explains the redshift
Redshift
In physics , redshift happens when light seen coming from an object is proportionally increased in wavelength, or shifted to the red end of the spectrum...

 of galaxies. He further concluded that an initial "creation
Ex nihilo
Ex nihilo is a Latin phrase meaning "out of nothing". It often appears in conjunction with the concept of creation, as in creatio ex nihilo, meaning "creation out of nothing"—chiefly in philosophical or theological contexts, but also occurs in other fields.In theology, the common phrase creatio ex...

-like" event must have occurred. In the 1980s, Alan Guth
Alan Guth
Alan Harvey Guth is an American theoretical physicist and cosmologist. Guth has researched elementary particle theory...

 and Andrei Linde
Andrei Linde
Andrei Dmitriyevich Linde is a Russian-American theoretical physicist and professor of Physics at Stanford University. Dr. Linde is best known for his work on the concept of the inflationary universe. He received his Bachelor of Science degree from Moscow State University. In 1975, Linde was...

 modified this theory by adding to it a period of inflation.

Einstein at first dismissed Friedmann, and then (privately) Lemaître, out of hand, saying that not all mathematics lead to correct theories. After Hubble's discovery was published, Einstein quickly and publicly endorsed Lemaître's theory, helping both the theory and its proposer get fast recognition.

Lemaître was also an early adopter of computers for cosmological calculations. He introduced the first computer to his university (a Burroughs E101) in 1958 and was one of the inventors of the Fast fourier transform
Fast Fourier transform
A fast Fourier transform is an efficient algorithm to compute the discrete Fourier transform and its inverse. "The FFT has been called the most important numerical algorithm of our lifetime ." There are many distinct FFT algorithms involving a wide range of mathematics, from simple...

 algorithm.

In 1933, Lemaître found an important inhomogeneous solution of Einstein's field equations
Einstein field equations
The Einstein field equations or Einstein's equations are a set of ten equations in Albert Einstein's general theory of relativity which describe the fundamental interaction of gravitation as a result of spacetime being curved by matter and energy...

 describing a spherical dust cloud, the Lemaître–Tolman metric.

In 1948 Lemaitre published
a polished mathematical essay "Quaternions et espace elliptique" which clarified an obscure space. William Kingdon Clifford
William Kingdon Clifford
William Kingdon Clifford FRS was an English mathematician and philosopher. Building on the work of Hermann Grassmann, he introduced what is now termed geometric algebra, a special case of the Clifford algebra named in his honour, with interesting applications in contemporary mathematical physics...

 had cryptically described elliptic space in 1873 at a time when versors were too common to mention. Lemaître developed the theory of quaternions from first principles so that his essay can stand on its own, but he recalled the Erlangen program
Erlangen program
An influential research program and manifesto was published in 1872 by Felix Klein, under the title Vergleichende Betrachtungen über neuere geometrische Forschungen...

 in geometry while developing the metric geometry of elliptic space. H. S. M. Coxeter, another contributor to elliptic geometry, summarized Lemaitre’s work for Mathematical Reviews
Mathematical Reviews
Mathematical Reviews is a journal and online database published by the American Mathematical Society that contains brief synopses of many articles in mathematics, statistics and theoretical computer science.- Reviews :...

.

Namesakes

  • The lunar crater Lemaître
    Lemaître (crater)
    Lemaître is a lunar impact crater that is located on the southern hemisphere on the far side of the Moon. It lies to the south of the older crater Minkowski, and north of Crommelin. To the east-southeast lies the crater Eijkman....

  • The Friedmann-Lemaître-Robertson-Walker universe
  • The Lemaître metric
    Lemaitre metric
    Lemaître coordinates are a particular set of coordinates for the Schwarzschild metric—a spherically symmetric solution to vacuum Einstein equation— obtained by Georges Lemaître in 1938...

  • The Lemaître observers in the Schwarzschild vacuum Frame fields in general relativity
    Frame fields in general relativity
    In general relativity, a frame field is a set of four orthonormal vector fields, one timelike and three spacelike, defined on a Lorentzian manifold that is physically interpreted as a model of spacetime...

  • The minor planet
    Minor planet
    An asteroid group or minor-planet group is a population of minor planets that have a share broadly similar orbits. Members are generally unrelated to each other, unlike in an asteroid family, which often results from the break-up of a single asteroid...

     1565 Lemaître
    1565 Lemaître
    1565 Lemaître is a main belt asteroid with an orbital period of 1352.5541294 days .The asteroid was discovered on November 25, 1948.-References:...


See also


External links