So, we have a “clock” which starts ticking the moment something dies.Obviously, this works only for things which were once living.That is, they take up less than would be expected and so they test older than they really are.
This will make old things look older than they really are.
However, even with such historical calibration, archaeologists do not regard C produced and therefore dating the system.
The amount of cosmic rays reaching the Earth varies with the sun's activity, and with the Earth's passage through magnetic clouds as the solar system travels around the Milky Way galaxy.
The strength of the Earth's magnetic field affects the amount of cosmic rays entering the atmosphere.
A stronger magnetic field deflects more cosmic rays away from the Earth.