Carbon dating news articles
The technique hinges on carbon-14, a radioactive isotope of the element that, unlike other more stable forms of carbon, decays away at a steady rate.
Organisms capture a certain amount of carbon-14 from the atmosphere when they are alive.
By measuring the ratio of the radio isotope to non-radioactive carbon, the amount of carbon-14 decay can be worked out, thereby giving an age for the specimen in question.
But that assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock.
Dendrochronology and radiocarbon dating have intertwined histories, she explains, with roots firmly planted at the UA.
A 1929 edition of National Geographic boasts, "The Secret Of The Southwest Solved By Talkative Tree Rings." The 35-page article, penned in whimsical prose, was written by Andrew Douglass, the UA scientist who invented tree ring science. In addition to his work as an astronomer at the UA's Steward Observatory, Douglass was the first to discover that tree rings record time.
Carbon dating looks at the ratio of radioactive carbon, which is naturally present at low levels in the atmosphere and food, to normal carbon within an organism.