The radioactive carbon isotope is no longer replenished; it only decays.
Test results from Middle Kingdom pyramid (Senwosret II).
Ancient Egypt’s population was restricted to the narrow confines of the Nile Valley with, we assume, a sparse cover of trees.
We focused our collection efforts on tiny pieces of these materials, along with reed and straw left by the ancient builders.
In 1984 we conducted radiocarbon dating on material from Egyptian Old Kingdom monuments (financed by friends and supporters of the Edgar Cayce Foundation).
By measuring how much C14 remains in a sample of organic material, we can estimate its age within a range of dates.
Samples older than 50,000 to 60,000 years are not useful for radiocarbon testing because by then, the amount of C14 remaining is too small to be dated.
We wanted to use science to test the accepted historical dates of several Old Kingdom monuments.
One radioactive, or unstable, carbon isotope is C14, which decays over time and therefore provides scientists with a kind of clock for measuring the age of organic material.
The number of dates from the two projects was only large enough to allow for statistical comparisons for the pyramids of Djoser, Khufu, Khafre, and Menkaure. First, there are significant discrepancies between the 19 dates for Khufu and Khafre, but not for Djoser and Menkaure.