It seems really farfetched to me, are we counting fossil rings or something?
In: Chemistry
I assume you mean fossils and organic matter. Organics and organisms are made of carbon. Carbon has a radioactive isotope C-14, which is made in the upper atmosphere after interactions of our atmosphere with cosmic rays. This C-14 isotope is absorbed by plants and other organisms and is incorporated in themselves. When these organisms are eaten by other organisms, they also get the C-14.
However, when an organism dies, it is no longer getting the C-14 isotope. As the C-14 isotope decays over time, it’s concentration in the remains of the organism becomes smaller and smaller. By measuring the observed concentration of C-14 in fossils or organic remains versus what would be expected if they were alive now, scientists can tell how long ago the organism died, thereby giving us radiocarbon dating.
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