How radio carbon dating works Chez free sex chat

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

And plants top up their radioactive carbon every time they turn carbon dioxide to food during photosynthesis.

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

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But old age isn't the only thing that affects the accuracy of carbon dating.

The level of radiocarbon in the atmosphere has varied over time — it was about two per cent higher 3,500 years ago, possibly due to factors affecting cosmic rays (like changes in solar cycles or the Earth's magnetic field).

And that something else starts where Earth meets space.

Earth's upper atmosphere is constantly being bombarded by cosmic rays (usually protons travelling at nearly the speed of light).

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.

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.

(You can read up on radioactivity and isotopes here).

Carbon-14, the radioactive version of carbon, is rare — it only makes up one trillionth of all the carbon in the world.

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

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