When an element undergoes radioactive decay, it creates radiation and turns into some other element.
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.
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.
For example, this study shows detectable levels of carbon-14 in a range of carbon-containing materials that are supposedly 1-500 million years old.
Surprisingly, the study includes from several different locations!
Libby and coworkers, and it has provided a way to determine the ages of different materials in archeology, geology, geophysics, and other branches of science.
Some examples of the types of material that radiocarbon can determine the ages of are wood, charcoal, marine and freshwater shell, bone and antler, and peat and organic-bearing sediments.
Age determinations can also be obtained from carbonate deposits such as calcite, dissolved carbon dioxide, and carbonates in ocean, lake, and groundwater sources.