is a technique used by scientists to learn the ages of biological specimens – for example, wooden archaeological artifacts or ancient human remains – from the distant past.It can be used on objects as old as about 62,000 years.

radiocarbon 14 dating procedure-61

Here’s an example using the simplest atom, hydrogen. Cosmic rays bombard Earth’s atmosphere, creating the unstable isotope carbon-14.

Radiocarbon dating uses isotopes of the element carbon. This isotope lets scientists learn the ages of once-living specimens from long ago.

Image via The Cosmic Story of Carbon-14 by Ethan Siegel, via Simon Swordy (U.

Chicago), via NASA of those two isotopes in a sample.

Most carbon on Earth exists as the very stable isotope carbon-12, with a very small amount as carbon-13.

Carbon-14 is an unstable isotope of carbon that will eventually decay at a known rate to become carbon-12.

Cosmic rays – high energy particles from beyond the solar system – bombard Earth’s upper atmosphere continually, in the process creating the unstable carbon-14. Because it’s unstable, carbon-14 will eventually decay back to carbon-12 isotopes.

Because the cosmic ray bombardment is fairly constant, there’s a near-constant level of carbon-14 to carbon-12 ratio in Earth’s atmosphere.

Organisms at the base of the food chain that photosynthesize – for example, plants and algae – use the carbon in Earth’s atmosphere.