Radiocarbon dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating ) is a method for determining the age of an object containing organic material by using the properties of radiocarbon , a radioactive isotope of carbon . The method was developed in the late 1940s at the University of Chicago by Willard Libby . It is based on the fact that radiocarbon ( 14 C) is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen . The resulting 14 C combines with atmospheric oxygen to form radioactive carbon dioxide , which is incorporated into plants by photosynthesis ; animals then acquire 14 C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of 14 C it contains begins to decrease as the ...