South Tyrol Museum of Archaeology. There's a small amount of radioactive carbon in all living organisms. When they die no new carbon is taken in by the dead organism. The carbon it contained at the time of death decays over a long period of time. By measuring the amount of carbon left in dead organic material the approximate time since it died can be worked out. For example, intwo hikers discovered a mummified man, preserved for centuries in the ice on an alpine mountain.
Some rocks contain traces of uranium. Uranium has a very long half-life and so by measuring how much uranium is left in a rock its approximate age can be which radioactive isotope is used in carbon dating out. Back to Radiation for life index. You're using the Internet Explorer 6 browser to view the BBC website. Our site will work much better if you change to a more modern browser.
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