Father Of The Big Bang, Catholic Priest Georges Lemaitre Pictured With Albert Einstein. “Georges Lemaitre a Belgian astrophysicist/Mathematician developed the theory of the Big Bang. In January 1933, Georges Lemaitre traveled with Albert Einstein to California for a series of seminars. After Georges Lemaitre detailed his Big Bang theory, Einstein stood up applauded, and said, “This is the most beautiful and satisfactory explanation of creation to which I have ever listened.”