Before I start, I'm not some young earth believer or anything, just want to understand how it works and if the assumptions are fair. So my understanding of carbon dating is that the ratio of C14 to C 12 is known (About 1 trillion to 1) and it is the same in the atmosphere as it is in organic material. Sicne C14 is not stable, it decays and the ratio in the organic compound becomes smaller and smaller since no more C14 is being produced. Using this you can estimate how old the thing was. Questions Once something dies, it can no longer produce an C12 or C 14 correct? How do we know the ratio of C14 to C12 to be constant. Has it always been 1 to 1 trillion. It seems to me if this is wrong, the whole thing falls apart. What assumptions do we base that this ratio is constant on? How doe we determine the half life of Carbon in the first place, or any element at that?