Start Radiocarbon dating stuff works

Radiocarbon dating stuff works

Not only that, we top up our carbon-14 levels every time we eat.

It's not that the radioactive carbon in air or food doesn't decay, it does.

But something else is going on that keeps producing new carbon-14 — otherwise it would have all turned to nitrogen millions of years ago.

And nuclear reactions have seen a leap in carbon-14 activity since 1945.

Luckily for us we have a record of atmospheric carbon-14 levels for every one of the last 12,000 years.

Radiocarbon dating is used to work out the age of things that died up to 50,000 years ago. As far as working out the age of long-dead things goes, carbon has got a few things going for it. The proteins, carbohydrates and fats that make up much of our tissues are all based on carbon.

Everything from the fibres in the Shroud of Turin to Otzi the Iceman has had their birthday determined the carbon-14 way. There's plenty of hydrogen, oxygen and nitrogen in living things too, but carbon's got something none of them do — a radioactive isotope that can take thousands of years to decay.

And after 11,460 years (two half-lives), only a quarter of the original carbon-14 atoms are left.