Carbon dating is rule on dating age
The ratio of normal carbon (carbon-12) to carbon-14 in the air and in all living things at any given time is nearly constant.Maybe one in a trillion carbon atoms are carbon-14.The carbon-14 atoms are always decaying, but they are being replaced by new carbon-14 atoms at a constant rate.At this moment, your body has a certain percentage of carbon-14 atoms in it, and all living plants and animals have the same percentage.The carbon-14 atoms that cosmic rays create combine with oxygen to form carbon dioxide, which plants absorb naturally and incorporate into plant fibers by photosynthesis.
Accurate tree ring records of age are available for a period extending 9,000 years into the past.The Lamont-Doherty scientists conducted their analyses on samples of coral drilled from a reef off the island of Barbados.The samples represented animals that lived at various times during the last 30,000 years. Alan Zindler, a professor of geology at Columbia University who is a member of the Lamont-Doherty research group, said age estimates using the carbon dating and uranium-thorium dating differed only slightly for the period from 9,000 years ago to the present.Since 1947, scientists have reckoned the ages of many old objects by measuring the amounts of radioactive carbon they contain.New research shows, however, that some estimates based on carbon may have erred by thousands of years.
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Dating Subject to Error But scientists have long recognized that carbon dating is subject to error because of a variety of factors, including contamination by outside sources of carbon.