“How did we get here?”That existential question about the universe has captivated humankind for centuries. Many scientists have attempted to answer it, including the Rev. Georges Lemaître, a Belgian cosmologist and Catholic priest. In 1927 he theorized that the universe was created from a single particle he called the “primeval atom.”That atom later disintegrated in an explosion, LeMaître figured, creating space, time, and an ever-expanding universe, according to the American Museum of Natural H...