In 1929, Edwin Hubble confirmed that the Universe is expanding. With that question settled, a far older one came back to haunt scientists: Did the Universe have a beginning? If so, what was going on before? Was there space, and was there time? 

The quest for an answer has a fascinating history, and the search is still very much part of the conversation in cosmology. Maybe there are a few lessons to be learned from the wisdom of our predecessors.

One of the first voices to address the issue of a beginning was the Belgian priest and cosmologist Georges Lemaître. Despite his love for physics, Lemaître followed his father’s advice (read: pressure). After a degree in civil engineering in 1913, he started to train as a mining engineer. 

Sometimes a single factor can change someone’s course in life. In my case, it was inorganic chemistry labs that convinced me to change my studies from chemical engineering to physics (against my father’s advice as well.) In Lemaître’s case, it was years of exposure to the horrors of World War I. When the war was over, Lemaître knew it was time to pursue his dream. By 1920, he had joined both a graduate program in mathematical physics and the Maison Saint Rombaut, an extension of the seminary of the Archdiocese of Malines. There, he would be trained for priesthood. 

In September 1923, Lemaître was ordained a priest. In October, he joined Arthur Eddington and his prestigious research group at Cambridge as a graduate student. After a year in England, Lemaître left for Harvard. He developed a solid foundation in theoretical physics and astronomy, a combination that would anchor his constant efforts to link the theoretical and observational aspects of cosmology. 

Creative and independent, in 1927 Lemaître wrote a paper in which he basically rediscovered Alexander Friedmann’s cosmological solutions predicting an expanding Universe. In the same paper, he showed that these solutions, as well as Willem de Sitter’s, also led to a linear velocity-distance relation for receding galaxies. 

Lemaître’s paper was published in an obscure journal and remained largely unnoticed. He did try to talk to Einstein about his results, but Einstein showed no interest. “Vos calculs sont corrects, mais votre physique est abominable,” Einstein told him — “Your calculations are correct, but your physics is abominable.” But Lemaître’s fate was about to change dramatically, and within a few years, Einstein himself would be applauding his ideas. 

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