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.
Half of the remaining Carbon-14 then decays over the next 5730 years leaving one fourth of the original amount.
By measuring the ratio of Carbon-14 in a sample and comparing it to the amount in a recently deceased sample its date can be determined.
Climate records from a Japanese lake are set to improve the accuracy of the dating technique, which could help to shed light on archaeological mysteries such as why Neanderthals became extinct.
Carbon dating is used to work out the age of organic material — in effect, any living thing.
Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food.
But that assumes that the amount of carbon-14 in the atmosphere was constant — any variation would speed up or slow down the clock.
Recall that atoms are the basic building blocks of matter.
Atoms are made up of much smaller particles called protons, neutrons, and electrons.
The Carbon-14 within a living organism is continually decaying, but as the organism is continuously absorbing Carbon-14 throughout its life the ratio of Carbon-14 to Carbon-12 atoms in the organism is the same as the ratio in the atmosphere.
Once an organism dies it stops taking in Carbon in any form.
Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.