Carbon dating accurate range
Once the radiocarbon concentration in a sample has been measured, the sample's age in "radiocarbon years" is determined mathematically.
The radiocarbon age must then be calibrated to determine the sample's age in calendar years.
This article will answer several of the most common creationist attacks on carbon-14 dating, using the question-answer format that has proved so useful to lecturers and debaters. Answer: Cosmic rays in the upper atmosphere are constantly converting the isotope nitrogen-14 (N-14) into carbon-14 (C-14 or radiocarbon).
Living organisms are constantly incorporating this C-14 into their bodies along with other carbon isotopes.
This, in fact, is the most significant factor contributing to loss of precision in radiocarbon dates today.
However, this contribution is usually only a few decades.
Carbon from these sources is very low in C-14 because these sources are so old and have not been mixed with fresh carbon from the air.The creationists who quote Kieth and Anderson never tell you this, however.Question: A sample that is more than fifty thousand years old shouldn't have any measurable C-14. Radiocarbon dating doesn't work well on objects much older than twenty thousand years, because such objects have so little C-14 left that their beta radiation is swamped out by the background radiation of cosmic rays and potassium-40 (K-40) decay. this isotope [K-40] accounts for a large part of the normal background radiation that can be detected on the earth's surface" (p. This radiation cannot be totally eliminated from the laboratory, so one could probably get a "radiocarbon" date of fifty thousand years from a pure carbon-free piece of tin.Older samples have a lower concentration of radiocarbon, but they can be (and often are) counted for longer periods of time to compensate for this lower concentration.By counting longer, the counting uncertainty in a radiocarbon measurement on a very old sample can be the same as that on a young sample.