Willard Frank Libby
Born: 17 December 1908, Grand Valley, CO, USA
Died: 8 September 1980, Los Angeles, CA, USA
Affiliation at the time of the award: University of California, Los Angeles, CA, USA
Prize motivation: "for his method to use carbon-14 for age determination in archaeology, geology, geophysics, and other branches of science"
Field: nuclear chemistry
Prize share: 1/1
Carbon is a fundamental component in all living material. In nature there are two variants, or isotopes: carbon-12, which is stable, and carbon-14, which is radioactive. Carbon-14 forms in the atmosphere when acted upon by the sun's ultraviolet light and then deteriorates. When an organism dies and the supply of carbon from the atmosphere ceases, the content of carbon-14 declines through radioactive decay at a fixed rate. In 1949 Willard Libby developed a method for applying this to determine the age of fossils and archeological relics.