Libby cleverly realized that carbon-14 in the atmosphere would find its way into living matter, which would thus be tagged with the radioactive isotope.Theoretically, if one could detect the amount of carbon-14 in an object, one could establish that object’s age using the half-life, or rate of decay, of the isotope.
However, the rates of movement of carbon throughout the cycle were not then known.
Libby and graduate student Ernest Anderson (1920–2013) calculated the mixing of carbon across these different reservoirs, particularly in the oceans, which constitute the largest reservoir.
In the absence of any historical data concerning the intensity of cosmic radiation, Libby simply assumed that it had been constant.
He reasoned that a state of equilibrium must exist wherein the rate of carbon-14 production was equal to its rate of decay, dating back millennia.
He was inspired by physicist Serge Korff (1906–1989) of New York University, who in 1939 discovered that neutrons were produced during the bombardment of the atmosphere by cosmic rays.
Korff predicted that the reaction between these neutrons and nitrogen-14, which predominates in the atmosphere, would produce carbon-14, also called radiocarbon.
Final editing and manuscript preparation was coordinated by M.
Generated COL1 species consensus sequences will be available in the Uni Prot Knowledgebase under the accession numbers C0HJN3–C0HJP8.
(Fortunately for him, this was later proven to be generally true.) For the second factor, it would be necessary to estimate the overall amount carbon-14 and compare this against all other isotopes of carbon.
Based on Korff’s estimation that just two neutrons were produced per second per square centimeter of earth’s surface, each forming a carbon-14 atom, Libby calculated a ratio of just one carbon-14 atom per every 10 carbon atoms on earth.
Laura Bush looks at books dating to the 1500s during a tour of the Ancient Library at the University of Turin guided by Paolo Novaria, Archives, left, and Enrico Artifoni, right, Saturday, Feb.