The technique hinges on carbon-14, a radioactive isotope of the element that, unlike other more stable forms of carbon, decays away at a steady rate.
Organisms capture a certain amount of carbon-14 from the atmosphere when they are alive.
Nyerup's words illustrate poignantly the critical power and importance of dating; to order time.
Radiocarbon dating has been one of the most significant discoveries in 20th century science.
By measuring the ratio of the radio isotope to non-radioactive carbon, the amount of carbon-14 decay can be worked out, thereby giving an age for the specimen in question.
But that assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock.
A common misconception about radiocarbon dating is that it gives a precise date---3577 B. In actual practice radiocarbon dating can only give a range of dates for a given sample---3650 to 3410 B.
C., for example---the true date lying somewhere in that range.
We know that it is older than Christendom, but whether by a couple of years or a couple of centuries, or even by more than a millenium, we can do no more than guess." [Rasmus Nyerup, (Danish antiquarian), 1802 (in Trigger, 19)]. - Data table used in "Version Fairbanks0805" available here as a PDF. [PDF] - View the entire 'Fairbanks0107' calibration curve with the option to zoom in on areas of interest. Mortlock, Tzu-Chien Chiu, Li Cao, Alexey Kaplan, Thomas P. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF). For sample results, click 'Compute' in This material is based upon work supported by the National Science Foundation under Grant Numbers ATM03-27722, ATM04-17909, and OCE99-11637.Of practical importance to a wide range of scientific disciplines is the radiocarbon calibration, which is used for converting radiocarbon ages to calendar years; essential for measuring time and rates of change for numerous scientific fields.