Albert Einstein and the Rev. Georges Lemaître in 1933. Credit: Wikimedia Commons

The Big Bang, which today is held as the beginning of the world, does not contradict the intervention of the divine creator, but requires it. Evolution in nature is not at odds with the notion of creation because evolution presupposes the creation of beings that evolve.

Who said it? Pope Francis, in 2014. If it surprises you that the leader of the world’s largest religious denomination would be such an unabashed fan of a materialist account of the creation of the world, you might be intrigued by two more data points. The Big Bang was the brainchild of a Catholic priest in 1927—and when Pope Pius XII seemed to endorse his theories…that priest told the pope to knock it off.

The Rev. Georges Lemaître was a Belgian priest but also a theoretical physicist and a mathematician. Born in 1894, he began studying for the priesthood in 1911 but joined the Belgian army in 1914, serving in World War I as an artillery officer. He was ordained for the Archdiocese of Mechelen-Brussels in 1923, also earning a doctorate along the way. While like many a priest-scholar before and since, Father Lemaître spent much of his life being mistaken for a Jesuit, he remained a diocesan priest and a member of the “Priestly Fraternity of the Friends of Jesus” throughout his life. 

A professor of physics at the Catholic University of Louvain from 1927 until his retirement in 1964, Lemaître was awarded a second doctorate by M.I.T. in 1927. He was in constant conversation with other prominent physicists in those years, including Albert Einstein (with whom he is pictured above), whose equations describing the universe were an early research subject. Between 1927 and 1931, he formulated and then proposed his “hypothesis of the primeval atom,” what we know today as the Big Bang (originally meant as a sneer): the notion that the entire universe began from a single incredibly dense atom whose explosion billions of years ago, and ongoing disintegration, has formed all matter in the universe as well as the fabric of space-time. 

Because most physicists up to then—including Einstein—believed the universe to be a static phenomenon, Lemaître’s idea was revolutionary, but eventually won acceptance by the larger academy. His work in the years that followed included an embrace of early computers to handle the increasingly complicated theoretical physics in which he and his peers were engaged.

Father Lemaître was surprised when Pope Pius XII weighed in on the Big Bang in a 1951 address to the Pontifical Academy of Sciences at the Vatican (where Lemaître was present). “Indeed, it seems that the science of today, by going back in one leap millions of centuries, has succeeded in being a witness to that primordial Fiat Lux, when, out of nothing, there burst forth with matter a sea of light and radiation, while the particles of chemical elements split and reunited in millions of galaxies,” the pope said, adding further that science “has indicated their beginning in time at a period about five billion years ago, confirming with the concreteness of physical proofs the contingency of the universe and the well-founded deduction that about that time the cosmos issued from the hand of the Creator. Creation, therefore, in time, and therefore, a Creator; and consequently, God!”

Hold on a hot second, said Father Lemaître and others in the aftermath. On the one hand, the Catholic Church’s ongoing embrace of science should be seen as an almost unmitigated good; on the other, Lemaître thought the pope had gone too far in his comments, and told him so in the aftermath. Why?

We were blessed last week at America to have a visit from Guy Consolmagno, S.J., the outgoing director of the Vatican Observatory, and got a chance to ask him why Lemaître was upset with the pope’s words. Several reasons, he said, but first among them is that the Big Bang is a hypothesis, not a fact—and like most science, it will be revised and found to be incomplete (or false) at some point; it should not be equated with an eternal truth expressed poetically in Scripture. (This has of course already happened—Pope Pius XII’s “five billion years ago” now looks more like 14 billion years ago.) 

Further, theology and science work best as dialogue partners in search of the truth; just as they need not be antagonists, they do not exist to justify the propositions of each other. Indeed, Lemaître had long argued that Catholic scientists should be careful to keep their faith separate from their science, once writing: “He does this not because his faith could involve him in difficulties, but because it has directly nothing in common with his scientific activity. After all, a Christian does not act differently from any non-believer as far as walking, or running, or swimming is concerned.”

“His conception of the relationship of science and faith was rather circumspect, carefully delineating their roles as ways of knowing,” Karl van Bibber, then professor and chairman of the Department of Nuclear Engineering at the University of California, Berkeley, told America in 2016. “Science for him was the methodology for understanding the physical cosmos; revealed religion taught truths important for salvation. He was quite content to observe that the findings of science were in no way discordant with scriptural revelation, and vice versa, but neither should overreach.”

Pope Pius XII seems to have heeded Lemaître’s words—though that hasn’t stopped later popes, including St. John Paul II and the aforementioned Pope Francis—from giving credence if not a papal imprimatur to the Big Bang.

In 1959, Lemaître was appointed the second president of the Pontifical Academy of Sciences. He retired from Louvain in 1964.

Father Lemaître seems to have dodged another science/faith bullet during the 1960s, when Pope Paul VI asked him to serve on the Pontifical Commission on Birth Control. His failing health—and his suggestion that mathematicians shouldn’t weigh in on moral theology—led him to decline to participate in a process that eventually culminated with the encyclical “Humanae Vitae” in 1968. 

Father Lemaître died in 1966 at the age of 71. Upon the 50th anniversary of his death in 2016, the Pontifical Academy of Sciences held a “Special Session on Cosmology” to recognize his achievements. The precis for the session noted that three days before Father Lemaître’s death, friends brought him news of the discovery of cosmic microwave background radiation. If those waves are indeed the leftover radiation from the origin of the universe, it would go a long way toward bolstering the Big Bang hypothesis. “Je suis content,” Lemaître is said to have replied. “maintenant on a la preuve.” 

“I’m happy. Now we have the proof.”

•••

Our poetry selection for this week is “Looking for Her,” by Eileen Markey. Readers can view all of America’s published poems here.

In other news, we are excited to announce a pilgrimage to Ireland in April 2026. Led by myself and America editor in chief Sam Sawyer, S.J., the trip, “The Land of Saints & Scholars: A Journey into the Heart & Soul of Ireland,” will be from April 19 to 28, 2026. Reserve your spot!

In this space every week, America features reviews of and literary commentary on one particular writer or group of writers (both new and old; our archives span more than a century), as well as poetry and other offerings from America Media. We hope this will give us a chance to provide you with more in-depth coverage of our literary offerings. It also allows us to alert digital subscribers to some of our online content that doesn’t make it into our newsletters.

Other recent Catholic Book Club columns:

Happy reading!

James T. Keane

James T. Keane is a Senior Editor at America.