Virtual dating radiocarbon answers
A number of stories are commonly circulated about a shell, or a piece of coal, or some other sample which supposedly yielded a radiocarbon date which could not possibly be correct.
Measurements can be made with a high degree of precision. Aardsma submitted a sample from a reed mat known to be over 5,000 years old.
The measurement, before calibration, came back with an error bar of /- about 60 radiocarbon years. It should be noted that these measurement uncertainties do not increase linearly as one goes back in time.
There is, in fact, no indication anywhere in the original reference that these samples were from the "Pennyslvanian"; nor is there any hint that they were expected to be "300 million years old"; these appear to be purely apocryphal embellishments to the original account.
Surely, what the Russians intended to convey (and what nearly everybody would understand), is that these samples were charcoal from a not too ancient campfire.
(Ham et al., page 68.) C ratio in the past, or that this is "the technique's Achilles' heel" is incorrect.
The whole validity of radiocarbon dating for the past 10,000 years---the time span of interest to biblical chronology---hangs only on the tree-ring chronologies which are used to calibrate it. .) This process does not involve any assumption about historic radiocarbon to stable carbon ratios because the radiocarbon concentration in the tree-ring samples would be affected in exactly the same way as the radiocarbon concentration in the specimen to be dated. To quote again from The Answers Book: Some recent, though controversial, research has raised the interesting suggestion that c (the speed of light) has decreased in historical times. If it is correct, then radioactive decay rates would automatically be affected, and would show artifically high ages.
This Radiocarbon reference must originally have been translated from Russian and it is not unreasonable to suppose that there was some loss of descriptive clarity as a result.
But it seems pretty clear that what is being described here is certainly not "Pennsylvanian coal".
Presented here are a few examples, exposing the truth about these stories.