Harold Urey

Born in Walkerton, Indiana, in 1893, Harold Clayton Urey studied thermodynamics under Gilbert N. Lewis at Berkeley, earned his PhD in 1923, and spent a year at Niels Bohr's institute in Copenhagen. At Columbia in 1931, his work separating isotopes led to the discovery of deuterium. During World War II he turned that skill toward uranium enrichment, heading the Columbia team that developed gaseous diffusion - the sole method used in the early postwar period. At the University of Chicago after the war, he speculated that Earth's early atmosphere was ammonia, methane, and hydrogen; his student Stanley Miller proved that mix plus electric sparks could yield amino acids. Later, isotope work opened paleoclimatic research. At the new UC San Diego in 1958, he helped build the science faculty and studied Apollo 11's Moon rocks. He once told astronaut Harrison Schmitt he'd volunteer for a one-way trip to the Moon and not care if he came back.