Love-hungry teenagers and archaeologists agree: dating is hard.
But while the difficulties of single life may be intractable, the challenge of determining the age of prehistoric artifacts and fossils is greatly aided by measuring certain radioactive isotopes.
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.
Carbon-14, or radiocarbon, is a naturally occurring radioactive isotope that forms when cosmic rays in the upper atmosphere strike nitrogen molecules, which then oxidize to become carbon dioxide.
Green plants absorb the carbon dioxide, so the population of carbon-14 molecules is continually replenished until the plant dies.
Some are found in these pipes, such as kimberlites, while other diamonds were liberated by water erosion and deposited elsewhere (called alluvial diamonds).
According to evolutionists, the diamonds formed about 1–3 billion years ago.
Though still heavily used, relative dating is now augmented by several modern dating techniques.
Radiocarbon dating involves determining the age of an ancient fossil or specimen by measuring its carbon-14 content.
They arrived at this conclusion by comparing age estimates obtained using two different methods - analysis of radioactive carbon in a sample and determination of the ratio of uranium to thorium in the sample.
In some cases, the latter ratio appears to be a much more accurate gauge of age than the customary method of carbon dating, the scientists said.
) is only 5,730 years—that is, every 5,730 years, half of it decays away.