George Gamow (March 4, 1904 – August 19, 1968), born Georgiy Antonovich Gamov (Ukrainian: Георгій Антонович Гамов, Russian: Георгий Антонович Гамов), was a Russian-born Soviet and American polymath, theoretical physicist and cosmologist. He was an early advocate and developer of Lemaître's Big Bang theory. He discovered a theoretical explanation of alpha decay by quantum tunneling, invented the liquid drop model and the first mathematical model of the atomic nucleus, and worked on radioactive decay, star formation, stellar nucleosynthesis and Big Bang nucleosynthesis (which he collectively called nucleocosmogenesis), and molecular genetics.