Radioactive dating cold environmemt
So the proportion of carbon-14 inside living things is the same as the proportion of carbon-14 in the atmosphere at that time.
But when we stop eating, or when plants stop photosynthesising, our carbon-14 levels no longer get topped up.
That's why radiocarbon dating is only reliable for samples up to 50,000 years old.
When those speedy protons hit atoms you end up with a few stray neutrons zipping around the place.
And when one of those energetic neutrons hits a nitrogen atom, the nitrogen spits out a proton.
With an extra neutron and one less proton, that's no longer a nitrogen atom — six protons plus eight neutrons spells carbon-14.
The newly formed carbon-14 atoms end up in carbon dioxide, which ends up in plants, which end up on our dinner plates as fruit, veg or a highly processed version of plants known as meat.