Dating Dispute over Birmingham Manuscript
The technique has revolutionized archaeology but is far from an exact science.
In July the University of Birmingham made headlines when it revealed two leaves of worn parchment recently rediscovered in its archives were probably made between AD568 and 645. Prophet Muhammad (PBUH) lived between AD570 and 632.
But there are twists and turns in the tale.
Dr. Mustafa Shah, from the Islamic studies department at the School of Oriental and African Studies in London, has questioned this date, according to the BBC.
He says the writing itself "is evolved and elaborate, intimating that it represented a mature form" of Arabic writing and places it several decades later.
Francois Deroche, a historian of the Quran at the College de France, also says he has "reservations" about radiocarbon dating of such manuscripts.
But this is just the latest in a series of surprises - and arguments - connected with the method.
All living things absorb tiny amounts of the radioactive isotope carbon 14 during their lives but this process halts upon death.
This stored C14 then starts to break down at a regular rate and by measuring how much is left in a given sample a calculation can be made of how long it is since the organism died.
American physicist Willard Libby developed the technique in the 1940s and it won him the Nobel Prize.
Radiocarbon dating is limited to objects that are approximately 300 to 50,000 years old due to either there being too little C14 to take a measurement or samples being too heavily contaminated.
The technique was quickly recognized as a watershed in archaeology - but it was not perfect.
Prof Gordon Cook, head of the SUERC Radiocarbon Dating Laboratory, based at the University of Glasgow, said: "The assumption was the amount of C14 in the atmosphere, and the rate at which organisms absorbed it, had been constant throughout history.
"Testing showed this was not true and in fact a sophisticated set of corrections - known as a calibration curve - had to be developed."
This was thrown into sharp relief when Prof Cook's team worked on the headline-grabbing dating of Richard III's skeleton.
The first dates came back as AD1430-1460, when Richard was known to have died in 1485.
"But then stable isotope analysis of the bones showed the individual had eaten a lot of seafood," he said. "This gives a reservoir effect that makes the age too old.
"When this was taken into account, the results came in at AD1475-1530. It's not a fiddle or a fudge, it is a proven method for getting the most accurate results."
Where results given by different methods disagree, Prof Cook is clear.
"Carbon dating is backed by scientific rigour, repeatable and verifiable. If someone said analysis of writing or decoration gave a different date, I would ask what backs up that analysis?"
