But that's not really how it is when scientists are working in their labs.To understand how the C-14 clock works and what processes are involved, let us consider the egg-timer.The clock was initially calibrated by dating objects of known age such as Egyptian mummies and bread from Pompeii; work that won Willard Libby the 1960 Nobel Prize in Chemistry.
When their dating methods say that something lived 30,000 years ago, they sound certain.
And on the basis of these methods, many scientists announce that the Bible's record of history is not accurate.
Anything that was once alive or that was produced by a living thing can be dated by using the radiocarbon method of dating.
This method, which received widespread attention in connection with the Dead Sea Scrolls, relies on the fact that all living things take in carbon, some of which is very slightly radioactive. To hear some people tell it, scientists have nearly absolute confidence in the dating methods they use.
Carbon is found in all of our cells, including bone cells. A very small part of the carbon in our body is radioactive C-14, which does change to a nitrogen atom.
Carbon atoms such as we have in the living body are two kinds. C-14, thus, disappears, like sand running through the hourglass.Marine records, such as corals, have been used to push farther back in time, but these are less robust because levels of carbon-14 in the atmosphere and the ocean are not identical and tend shift with changes in ocean circulation.Bronk Ramsey’s team aimed to fill this gap by using sediment from bed of Lake Suigetsu, west of Tokyo.Preserved leaves in the cores — “they look fresh as if they’ve fallen very recently”, Bronk Ramsey says — yielded 651 carbon dates that could be compared to the calendar dates of the sediment they were found in.The recalibrated clock won’t force archaeologists to abandon old measurements wholesale, says Bronk Ramsey, but it could help to narrow the window of key events in human history.As a rule, carbon dates are younger than calendar dates: a bone carbon-dated to 10,000 years is around 11,000 years old, and 20,000 carbon years roughly equates to 24,000 calendar years.