Lemaitre

Georges Lemaître, often rendered as Lemaître in French, (1894–1966) was a Belgian priest, astronomer, and professor renowned for articulating the concept of an expanding universe and for proposing the hypothesis of the primeval atom, an early form of what would become the Big Bang theory.

Born in Charleroi, Lemaître pursued studies in mathematics and physics at the Catholic University of Leuven while fulfilling clerical duties as a priest. He conducted cosmology research and rose to prominence as a professor in Leuven’s physics department. His work bridged theoretical physics and observational astronomy, emphasizing the role of general relativity in understanding cosmic evolution.

In 1927, Lemaître published a paper presenting a dynamical solution to Einstein’s field equations that implied the expansion of space. He later argued that the universe began from a single, dense state—the primeval atom—and he connected this idea to observational data, interpreting galactic redshifts as evidence of cosmic expansion, which anticipated Edwin Hubble’s subsequent empirical findings. Although he introduced the expanding-universe model earlier, the broader reception of his ideas grew over the following decades.

His contributions helped establish modern cosmology by linking general relativity with astronomical observations and by providing a coherent narrative for the history of the universe. The term “Big Bang” was popularized decades later by Fred Hoyle, who used it descriptively rather than as a formal label. Lemaître’s legacy is honored in astronomy and physics through recognition such as lunar and scientific tributes; he is widely regarded as a founder of contemporary cosmology.