Application of carbon dating
It is assumed that the ratio has been constant for a very long time before the industrial revolution. (For on it hangs the whole validity of the system.) Why did W. Libby, the brilliant discoverer of this system, assume this?
C, we find that this ratio is the same if we sample a leaf from a tree, or a part of your body.As soon as it dies, however, the C ratio gets smaller.In other words, we have a ‘clock’ which starts ticking at the moment something dies.Unfortunately for the ‘old-Earth’ advocates, the studies of such renowned atmospheric physicists as Suess and Lingenfelter show that C to start with, so they have an even greater error.In other words, the further you go back, the more you have to shrink the radiocarbon dates to make them fit the facts.
C-14 is another radioactive isotope that decays to C-12. Because of its short half-life, the number of C-14 isotopes in a sample is negligible after about 50,000 years, making it impossible to use for dating older samples.