However, there is strong evidence which suggests that radioactive decay may have been greatly accelerated in the unobservable past.
We must also assume that the ratio of C-12 to C-14 in the atmosphere has remained constant throughout the unobservable past (so we can know what the ratio was at the time of the specimen's death).
It is naturally unstable and so it will spontaneously decay back into N-14 after a period of time.
After about 10 half-lives, the amount of radiocarbon left becomes too miniscule to measure and so this technique isn't useful for dating specimens which died more than 60,000 years ago.
Another limitation is that this technique can only be applied to organic material such as bone, flesh, or wood. Carbon Dating - The Premise Carbon dating is a dating technique predicated upon three things: Carbon Dating - The Controversy Carbon dating is controversial for a couple of reasons.
Because carbon-14 decays at this constant rate, an estimate of the date at which an organism died can be made by measuring the amount of its residual radiocarbon.
Scientists use a technique called radiometric dating to estimate the ages of rocks, fossils, and the earth.
The amount of cosmic rays penetrating the earth's atmosphere is itself affected by things like the earth's magnetic field which deflects cosmic rays.