Urey was born in Walkerton, Indiana, on April 29, 1893. He earned a bachelor's degree in zoology from Montana State University in 1917 and a Ph.D. in chemistry from the University of California in 1923. From 1923 to 1924, he did post-graduate research on the theory of atomic structure under Niels Bohr at the Institute of Theoretical Physics in Copenhagen, Denmark. He held teaching positions at the University of Montana (1919-1921), Johns Hopkins University (1924-1929), Columbia University (1929-1945), the University of Chicago (1945-1952), and the University of California (1952-1981).

Urey received the Nobel Prize in chemistry in 1934 for his discovery of deuterium, the isotope of hydrogen with atomic weight of 2. Frederick Soddy's discovery of isotopes in 1913 had raised the possibility that an isotope of hydrogen other than the familiar hydrogen-1 might exist. That possibility intrigued scientists from all fields. Hydrogen is the simplest of all elements with atoms that contain only a single...