Method of relative dating

Then Richard Leakey found a skull (called KNM-ER 1470) the KBS tuff, a skull that looked far too modern to be 3 million years old.

So Curtis and others redated the KBS tuff using selected pumice and feldspar samples, and obtained an age of 1.82 million years.

Subsequently the shroud was made available for scientific examination, first in 19 by a committee appointed by Cardinal Michele Pellegrino .

Even for the first investigation, there was a possibility of using radiocarbon dating to determine the age of the linen from which the shroud was woven.

Carbon 14 is continually being created in the Earth's atmosphere by the interaction of nitrogen and gamma rays from outer space.Since atmospheric carbon 14 arises at about the same rate that the atom decays, the Earth's levels of carbon 14 have remained constant.In living organisms, which are always taking in carbon, the levels of carbon 14 likewise stay constant.But in a dead organism, no new carbon is coming in, and its carbon 14 gradually begins to decay.So by measuring carbon 14 levels in an organism that died long ago, researchers can figure out when it died.