Mgr Georges Lemaître, Father of the Big Bang

Pictured: Mgr Georges Lemaître, priest, astronomer, professor of physics, first proposer of Big Bang Theory, chats to Albert Einstein in California in 1932. (H/T: Dr. Marcellino D’Ambrosio)

The following is an excerpt from COSMIC HORIZONS: ASTRONOMY AT THE CUTTING EDGE, edited by Steven Soter and Neil deGrasse Tyson, a publication of the New Press. © 2000 American Museum of Natural History. To order the book, call 1-800-233-4830, or go to (Source: American Museum of Natural History, Abbreviated: amnh)

According to the Big Bang theory, the expansion of the observable universe began with the explosion of a single particle at a definite point in time. This startling idea first appeared in scientific form in 1931, in a paper by Georges Lemaître, a Belgian cosmologist and Catholic priest. The theory, accepted by nearly all astronomers today, was a radical departure from scientific orthodoxy in the 1930s. Many astronomers at the time were still uncomfortable with the idea that the universe is expanding. That the entire observable universe of galaxies began with a bang seemed preposterous.

Lemaître was born in 1894 in Charleroi, Belgium. As a young man he was attracted to both science and theology, but World War I interrupted his studies (he served as an artillery officer and witnessed the first poison gas attack in history). After the war, Lemaître studied theoretical physics, and in 1923 was ordained as an abbé. The following year, he pursued his scientific studies with the distinguished English astronomer Arthur Eddington, who regarded him as “a very brilliant student, wonderfully quick and clear-sighted, and of great mathematical ability.” Lemaître then went on to America, where he visited most of the major centers of astronomical research. Later, he received his Ph.D. in physics from the Massachusetts Institute of Technology.

In 1925, at age 31, Lemaître accepted a professorship at the Catholic University of Louvain, near Brussels, a position he retained through World War II (when he was injured in the accidental bombing of his home by U.S. forces). He was a devoted teacher who enjoyed the company of students, but he preferred to work alone. Lemaître’s religious interests remained as important to him as science throughout his life, and he served as President of the Pontifical Academy of Sciences from 1960 until his death in 1966.

In 1927, Lemaître published in Belgium a virtually unnoticed paper that provided a compelling solution to the equations of General Relativity for the case of an expanding universe. His solution had, in fact, already been derived without his knowledge by the Russian Alexander Friedmann in 1922. But Friedmann was principally interested in the mathematics of a range of idealized solutions (including expanding and contracting universes) and did not pursue the possibility that one of them might actually describe the physical universe. In contrast, Lemaître attacked the problem of cosmology from a thoroughly physical point of view, and realized that his solution predicted the expansion of the real universe of galaxies that observations were only then beginning to suggest.

By 1930, other cosmologists, including Eddington, Willem de Sitter, and Einstein, had concluded that the static (non-evolving) models of the universe they had worked on for many years were unsatisfactory. Furthermore, Edwin Hubble, using the world’s largest telescope at Mt. Wilson in California, had shown that the distant galaxies all appeared to be receding from us at speeds proportional to their distances. It was at this point that Lemaître drew Eddington’s attention to his earlier work, in which he had derived and explained the relation between the distance and the recession velocity of galaxies. Eddington at once called the attention of other cosmologists to Lemaître’s 1927 paper and arranged for the publication of an English translation. Together with Hubble’s observations, Lemaître’s paper convinced the majority of astronomers that the universe was indeed expanding, and this revolutionized the study of cosmology.

A year later, Lemaître explored the logical consequences of an expanding universe and boldly proposed that it must have originated at a finite point in time. If the universe is expanding, he reasoned, it was smaller in the past, and extrapolation back in time should lead to an epoch when all the matter in the universe was packed together in an extremely dense state. Appealing to the new quantum theory of matter, Lemaître argued that the physical universe was initially a single particle—the “primeval atom” as he called it—which disintegrated in an explosion, giving rise to space and time and the expansion of the universe that continues to this day. This idea marked the birth of what we now know as Big Bang cosmology.

It is tempting to think that Lemaître’s deeply-held religious beliefs might have led him to the notion of a beginning of time. After all, the Judeo-Christian tradition had propagated a similar idea for millennia. Yet Lemaître clearly insisted that there was neither a connection nor a conflict between his religion and his science. Rather he kept them entirely separate, treating them as different, parallel interpretations of the world, both of which he believed with personal conviction. Indeed, when Pope Pius XII referred to the new theory of the origin of the universe as a scientific validation of the Catholic faith, Lemaître was rather alarmed. Delicately, for that was his way, he tried to separate the two:

“As far as I can see, such a theory remains entirely outside any metaphysical or religious question. It leaves the materialist free to deny any transcendental Being… For the believer, it removes any attempt at familiarity with God… It is consonant with Isaiah speaking of the hidden God, hidden even in the beginning of the universe.”

In the latter part of his life, Lemaître turned his attention to other areas of astronomical research, including pioneering work in electronic computation for astrophysical problems. His idea that the universe had an explosive birth was developed much further by other cosmologists, including George Gamow, to become the modern Big Bang theory. While contemporary views of the early universe differ in many respects from Lemaître’s “primordial atom,“ his work had nevertheless opened the way. Shortly before his death, Lemaître learned that Arno Penzias and Robert Wilson had discovered the cosmic microwave background radiation, the first and still most important observational evidence in support of the Big Bang.

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15 Responses to Mgr Georges Lemaître, Father of the Big Bang

  1. toadspittle says:


    There seems a little dispute over paternity here, but let’s not be picky. Lemaire was clearly a brilliant man. And wise enough to state that his theory did not “prove” that God exists: “As far as I can see, such a theory remains entirely outside any metaphysical or religious question. It leaves the materialist free to deny any transcendental Being… “ That is real scientific honesty. Thinks Toad.


  2. toadspittle says:

    .(Toad begs Lemaitre’s pardon for misspelling his name, and for the fact that he does not know how to put the little hat on the “i.”)


  3. JabbaPapa says:

    And wise enough to state that his theory did not “prove” that God exists: “As far as I can see, such a theory remains entirely outside any metaphysical or religious question. It leaves the materialist free to deny any transcendental Being… “ That is real scientific honesty. Thinks Toad.

    I agree.

    And FWIW, it’s rîîîîîllly rîîîîîllly rîîîîîllly êâsy !!!!


  4. Dick Puhlir says:

    Has Mr Papa been circumflexed?


  5. toadspittle says:


    Pondering this excellent “thread,” once more, Toad whistfully wonders what Mgr. Lemaitre would have made of Toad’s question the other day:
    I have often said on here …that mankind is responsible for far too many of the world’s ills, wars and general beastliness of that ilk.
    But surely not for earthquakes, floods, forest fires (set by lightning), tsunamis, volcanic eruptions, tornados, Malaria, the Black Death, Herod’s Evil, Scrofula, the Staggers, Leprosy, St Vitus Dance …(etc.)
    And, as I understand it, these, and many even more colourful afflictions, are God’s punishment for Original Sin. Is this really so? If it is so, as Unamuno says, “Wherefore?”

    We must presume that Lemaitre had no doubt that earthquakes, and the like, preceded the arrival of man by several millions of years.
    And, as such, cannot be punishment for man’s original sin. So we ask again, “Wherefore?”


  6. JabbaPapa says:

    We must presume that Lemaitre had no doubt that earthquakes, and the like, preceded the arrival of man by several millions of years.

    And, as such, cannot be punishment for man’s original sin. So we ask again, “Wherefore?”

    As far as I know there are three answers for this, although the more strictly theological answer is of course “dunno”.

    1) The Fall of Man altered the state of the Universe so that these evils occur — God existing outside of time does not need to obey causality in such a case, so that the consequence can precede the cause (but then, this assumes the literal truth of the Garden of Eden story, that is not a requirement of Catholics)

    2) (the one I prefer) Original Sin is the knowledge of Godd and Evil — so that we sinfully interpret various natural phenomena as being “evil”, instead of understanding them as being a part of God’s Plan

    3) These events are caused by a Cosmic Evil, that partakes of the Mystery of Evil, and is therefore not fully comprehensible, though it affects the good, the bad, and the ugly alike in the disasters and plagues that it causes.


  7. JabbaPapa says:

    knowledge of Godd and Evil >>> knowledge of Good and Evil (of course)


  8. kathleen says:

    Jabba, thank you. I think that is a really astute and profound reply to Toad’s eternal question: “why do natural evils occur?“, (i.e. those that can’t be directly attributed to man). I don’t think any other explanation can go any nearer clearing up this ongoing puzzle in the minds of many people (not just Toad’s), as the ones you have offered. This question will still remain a ‘mystery’ in many ways of course, but so it should. It forms part of the great unknown that man shall always be exploring and scrutinising.

    The existence of God and the whyerefore of, “Je pense donc je suis“, has not been offered to us on a plate. If it had been, Faith in God would have no value. That is why man needs to continually search for his answers.


  9. kathleen says:

    I think Toad should write a little note to his chum Santa Claus – in whom he apparently does believe – and ask him to pop a copy of the book (from which this fascinating excerpt is taken) into his Christmas stocking! 😉


  10. toadspittle says:

    Well, very informative from Jabba, at least, although “dunno” may do for him, it won’t for Toad.
    At least he won’t philosophifcally (or theosophically) commit on such a basis.
    And thanks to Kathleen as well.
    Toad suggests the idea that earthquakes and the like are “natural evils” gets us off on the wrong foot. A tsunami is no more “evil” than a tiger or a viper, or asthma. True it/they may cause us great dismay, but that is not “evil.”. Until we can solve, or find a coherent answer, to this vital “puzzle” it’s safer to withold judgement on God and His works. Thinks Toad..

    The world as we see it is not evil. It is, however, alive. The idea of “saving the planet” (to digress for a moment) is nonsense. If the planet was entirely covered in six feet deep of concrete, the planet wouldn’t care a bit, just go so spinning serenly.

    However, this whole topic is far more thought-provoking and worthy of our serious consideration than fretting whether or not a few “gays” getting wed will mean the end of civilisation as we know it.
    They’ll do it anyway. And thumb their noses at the rest of us.

    Thinks Toad, who intends to get his hands on the book in question.
    The interesting words, for him, in the article’s opening sentence, are “observable universe.” Suggesting…well quite a few things.

    (Knowledge of Godd and Evil, is very good, also thinks Toad – better than the alternative in fact!)


  11. Dick Puhlir says:

    The French pronounce this ‘Beeg Bong’. This rightly adds to the pleasure of the people.

    Yet I ask you, how on earth did one respondent above skilfully manage to involve gay marriage in the Beeg Bong Theory? This surpasseth all understanding.

    But it´s fun. And we don´t get enough of that.


  12. toadspittle says:

    Whereas in Spain, we call it “El Biggo Bangio.”


  13. Dick Puhlir says:

    No parlo Italiano as we say in Liverpool.


  14. golden chersonnese says:

    Toad, a passing thought. If the Earth were perfect it would already be Heaven and Man would have no dominion over it, as that would already have been bagsed by a Certain Other.

    Oh well, nice try anyhow.


  15. toadspittle says:

    “Toad, a passing thought. If the Earth were perfect it would already be Heaven…”

    When did Toad ever suggest the Earth, should, could, would, or might ever be perfect, Godlen?

    Just not quite as nasty as it is now, would do nicely, for a start. We can all think of ways how. And we are working on it. Some ways being tried now are called “medicine.”
    We can all envision a better planet – one that doesn’t have malaria on it, for example. Not a perfect planet, to be sure. But a bit less horrible.
    Do you not think that a ricketts-free world woud be a better one? Of course you do!
    Toad is well aware that perfection is not to be found, in this world or the next.
    Unlike some Catholics.

    The point he’s trying, and clearly failing, to get over – is that if earthquakes, smallpox and the like are, as Jabba and Kathleen suggest, “natural evils” why did God create them? This is, as we all agree a vital question, and “Dunno” seems a sadly unsatisfactory answer. To Toad.

    Toad’s theory, for what it’s worth, is that these kind of “events” are the price we must pay for finding ourselves trying desperately to survive on an impersonal, dangerous, volatile, and ultimately fatal planet.
    Neither good nor bad. Nobody created these unfortunate scenarios and nobody is to blame.
    It’s life. On God’s Earth, if you believe in Him.

    If you don’t believe, or aren’t sure, well…

    (Toad will have to quit CP&S soon. He’s getting serious and preachy. And long-winded.)


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