Carbon dating doesn t
Perhaps no concept in science is as misunderstood as "carbon dating." Almost everyone thinks carbon dating speaks of millions or billions of years.
But, carbon dating can't be used to date either rocks or fossils.
The changing ratio of C-12 to C-14 indicates the length of time since the tree stopped absorbing carbon, i.e., the time of its death.
Obviously, if half the C-14 decays in 5,730 years, and half more decays in another 5,730 years, by ten half-lives (57,300 years) there would be essentially no C-14 left.
Robert Whitelaw has done a very good job illustrating this theory using about 30,000 dates published in Radio Carbon over the last 40 years.
Carbon normally occurs as Carbon-12, but radioactive Carbon-14 may sometimes be formed in the outer atmosphere as Nitrogen-14 undergoes cosmic ray bombardment.
The resulting C-14 is unstable and decays back to N-14 with a measured half-life of approximately 5,730 years.
Since it would only take less than 50,000 years to reach equilibrium from a world with no C-14 at the start, this always seemed like a good assumption.
That is until careful measurements revealed a significant disequalibrium. All the present C-14 would accumulate, at present rates of production and build up, in less than 30,000 years!