Where does Carbon-14 Come From?
It is continually being generated in the upper atmosphere. As cosmic rays (highly ionizing radiation from outer space) enter the atmosphere, some collide with atoms, knocking off neutrons. When one of these neutrons is absorbed by an atom of nitrogen (14N), that atom emits a proton, changing that atom to 14C. Most of these new atoms of 14C combine with oxygen to form carbon-dioxide (CO2) which is mildly radioactive. Wind and other sources of diffusion distribute these new molecules throughout the Earth’s atmosphere. These eventually approach equilibrium with other CO2 atoms and mix into the “carbon cycle of life.” Some Disturbing Assumptions Willard F. Libby invented this dating system, and wrote the definitive book on the subject. Among other puzzling factors are the Specific Decay Rate (SDR) and the Specific Production Rate (SPR). If the atmosphere is in 14C equilibrium, these two numbers should be the same. But they’re not. The SPR of 14C was thought to be 18.8 atoms per gram of tot
