A very small percentage of carbon, however, consists of the isotope carbon 14, or radiocarbon, which is unstable.Carbon 14 has a half-life of 5,780 years, and is continuously created in Earth's atmosphere through the interaction of nitrogen and gamma rays from outer space.

Libby thus reasoned that by measuring carbon 14 levels in the remains of an organism that died long ago, one could estimate the time of its death.

This procedure of radiocarbon dating has been widely adopted and is considered accurate enough for practical use to study remains up to 50,000 years old.

One of the most frequent uses of radiocarbon dating is to estimate the age of organic remains from archaeological sites.

Carbon dating, also known as radiocarbon dating, is a method of estimating the age of carbon-bearing materials up to 60,000 years old.

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. 1979, 1986 © Harper Collins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cite This Source radiocarbon dating A technique for measuring the age of organic remains based on the rate of decay of carbon 14.

Because the ratio of carbon 12 to carbon 14 present in all living organisms is the same, and because the decay rate of carbon 14 is constant, the length of time that has passed since an organism has died can be calculated by comparing the ratio of carbon 12 to carbon 14 in its remains to the known ratio in living organisms. Our Living Language : In the late 1940s, American chemist Willard Libby developed a method for determining when the death of an organism had occurred.He first noted that the cells of all living things contain atoms taken in from the organism's environment, including carbon; all organic compounds contain carbon.Most carbon consists of the isotopes carbon 12 and carbon 13, which are very stable.However, it is also used to determine ages of rocks, plants, trees, etc. When the sun’s rays reach them, a few of these particles turn into carbon 14 (a radioactive carbon).The highest rate of carbon-14 production takes place at altitudes of 9 to 15 km (30,000 to 50,000 ft).At high geomagnetic latitudes, the carbon-14 spreads evenly throughout the atmosphere and reacts with oxygen to form carbon dioxide.