How can isotopes be used in dating archaeological
It takes about 5,730 years for half of a sample of radiocarbon to decay back into nitrogen.
It takes another 5,730 for half of the remainder to decay, and then another 5,730 for half of what's left then to decay and so on.
When a creature dies, it ceases to consume more radiocarbon while the C-14 already in its body continues to decay back into nitrogen.
So, if we find the remains of a dead creature whose C-12 to C-14 ratio is half of what it's supposed to be (that is, one C-14 atom for every two trillion C-12 atoms instead of one in every trillion) we can assume the creature has been dead for about 5,730 years (since half of the radiocarbon is missing, it takes about 5,730 years for half of it to decay back into nitrogen).
We have to assume, for example, that the rate of decay (that is, a 5,730 year half-life) has remained constant throughout the unobservable past.
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).
First of all, it's predicated upon a set of questionable assumptions.The results showed that Ötzi died over 5000 years ago, sometime between 33 BC. Uranium has a very long half-life and so by measuring how much uranium is left in a rock its approximate age can be worked out. This is how carbon dating works: Carbon is a naturally abundant element found in the atmosphere, in the earth, in the oceans, and in every living creature.Precise measurements taken over the last 140 years have shown a steady decay in the strength of the earth's magnetic field.
This means there's been a steady increase in radiocarbon production (which would increase the ratio). God, the Father, sent His only Son to satisfy that judgment for those who believe in Him.There's a small amount of radioactive carbon-14 in all living organisms.When they die no new carbon-14 is taken in by the dead organism.C-12 is by far the most common isotope, while only about one in a trillion carbon atoms is C-14.