Radiocarbon dating not accurate ancient rome dating
So calculating the age range of a once-living sample involves measuring the 14C/12C ratio, and using this the known half-life to estimate the length of time since the sample died.
But when we stop eating, or when plants stop photosynthesising, our carbon-14 levels no longer get topped up.
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.
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.
By about 58,000 years (ten half-lives) after an organism has died, there's so little radioactive carbon left (less than 1/1000) that calculations of age are no longer accurate.