Holocene radiometric dating
This limit is currently accepted by nearly all radiocarbon dating practitioners.
It follows that the older a date is, even within this 'limit', the greater are the doubts about the date's accuracy.
But in actual practice, we know neither the original ratios nor if the specimen has been contaminated and are forced to make what we hope are reasonable assumptions.
The tiny initial amount of C14, the relatively rapid rate of decay (the half-life of C14 is currently about 5700 years) and the ease with which samples can become contaminated make radiocarbon dating results for samples "older" than about 50,000 years effectively meaningless.
Usually a proton is knocked out of the nitrogen atom's nucleus and is replaced with the neutron.
The proton takes an electron with it and becomes an atom of hydrogen.
If we know what the original ratios of C14 to C12 were in the organism when it died, and if we know that the sample has not been contaminated by contact with other carbon since its death, we should be able to calculate when it died by its C14 to C12 ratio.Surely 15,000 years of difference on a single block of soil is indeed a gross discrepancy!And how could the excessive disagreement between the labs be called insignificant, when it has been the basis for the reappraisal of the standard error associated with each and every date in existence?Radiocarbon dating has somehow avoided collapse onto its own battered foundation, and now lurches onward with feigned consistency.The implications of pervasive contamination and ancient variations in carbon-14 levels are steadfastly ignored by those who base their argument upon the dates.
However, because it has too many neutrons for the number of protons it contains, it is not a stable atom.