Young earth creationists dismiss radiometric dating as unreliable, whats the truth?
closed as not a real question by David Zaslavsky♦ Oct 22 '12 at 13:58
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The main thing is that it's consistent with other forms of dating. Radiometric dating, for instance, will say that deeper levels of sediment are older than shallower levels of sediment. It will give similar fossils similar ages, even when the fossils are widely separated.
And one thing that the young Earth creationists need to explain if they're going to be down on radiometric dating--why do all subterranean pieces of dead organic matter have lower relative abundances of Carbon-14 than ones exposed to the atmosphere? What is their proposed mechanism for these abundances changing?
Radiometric dating is very reliable in theory - the decay of radioactive materials is very-very predictable.
But like any other bit of experimental physics "the difference between practice and theory is small in theory but large in practice."
It's especially tricky for Carbon14 dating (which most recent stuff relies on).
The creation rate of C14 (and so the proportion in the atmosphere) depends on the suns activity - so a lot of dates which assumed a constant rate are known to be wrong. We can now calibrate this out by looking at C14 in tree rings of a known age - but the charge of "C14 dates are wrong" is used by nutters (sorry creationists) either deliberately or in ignorance.
We also assume that the sample died with the same ratio of C12/C14 as in the atmosphere, this may not be true if they got the carbon in their diet from geological sources, eg by eating a lot of deep sea fish. This led to bodies of monks being discovered in europe with new world diseases being dated to before columbus