Used in radiocarbon dating
In 1949, American chemist Willard Libby, who worked on the development of the atomic bomb, published the first set of radiocarbon dates.
His radiocarbon dating technique is the most important development in absolute dating in archaeology and remains the main tool for dating the past 50,000 years.
The Greeks consider the first Olympic Games as the beginning or 776 BC.
The Muslims count the Prophet’s departure from Mecca, or the Hegira, as their beginning at AD 662.
The Mayan calendar used 3114 BC as their reference.
More recently is the radiocarbon date of 1950 AD or before present, BP.
Long tree-ring sequences have been developed throughout the world and can be used to check and calibrate radiocarbon dates.
One good example would be the elevated levels of Carbon-14 in our atmosphere since WWII as a result of atomic bombs testing.
As long as there is organic material present, radiocarbon dating is a universal dating technique that can be applied anywhere in the world.
It is good for dating for the last 50,000 years to about 400 years ago and can create chronologies for areas that previously lacked calendars.
Radiocarbon is then taken in by plants through photosynthesis, and these plants in turn are consumed by all the organisms on the planet.
So every living thing has a certain amount of radiocarbon within them.