Accuracy in carbon 14 dating
Scientists at the Lamont-Doherty Geological Laboratory of Columbia University at Palisades, N.Y., reported today in the British journal Nature that some estimates of age based on carbon analyses were wrong by as much as 3,500 years.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.They are then able to calibrate the carbon dating method to produce fairly accurate results.Carbon dating is thus accurate within the timeframe set by other archaeological dating techniques.It is too soon to know whether the discovery will seriously upset the estimated dates of events like the arrival of human beings in the Western Hemisphere, scientists said.But it is already clear that the carbon method of dating will have to be recalibrated and corrected in some cases.
Carbon dating is used to work out the age of organic material — in effect, any living thing.
In principle, any material of plant or animal origin, including textiles, wood, bones and leather, can be dated by its content of carbon 14, a radioactive form of carbon in the environment that is incorporated by all living things.
Because it is radioactive, carbon 14 steadily decays into other substances.
Carbon dating is somewhat accurate because we are able to determine what the ratio was in the unobservable past to a certain extent.
By taking a carboniferous specimen of known age (that is, a specimen which we are able to date with reasonable certainty through some archaeological means), scientists are able to determine what the ratio was during a specimen's lifetime.