Carbon follows this pathway through the food chain on Earth so that all living things are using carbon, building their bodies until they die.
A tiny part of the carbon on the Earth is called Carbon-14 (C14), or radiocarbon.
We know that it is older than Christendom, but whether by a couple of years or a couple of centuries, or even by more than a millenium, we can do no more than guess." [Rasmus Nyerup, (Danish antiquarian), 1802 (in Trigger, 19)].
The person who wrote these words lived in the 1800s, many years before archaeologists could accurately date materials from archaeological sites using scientific methods.
The relative dating method worked very well, but only in sites which were had a connection to the relative scale. When radiocarbon dating was developed, it revolutionised archaeology, because it enabled them to more confidently date the past, and to build a more accurate picture of the human past.
The archaeologist Colin Renfrew (1973) called it the development of this dating method 'the radiocarbon revolution' in describing its great impact upon the human sciences.
Libby later received the Nobel Prize in Chemistry in 1960 for the radiocarbon discovery.
Today, there are over 130 radiocarbon dating laboratories around the world producing radiocarbon dates for the scientific community.
He and two students first measured the "half-life" of radiocarbon.In the 1940s, scientists succeeded in finding out how long it takes for radiocarbon to disappear, or decay, from a sample of carbon from a dead plant or animal.Willard Libby, the principal scientist, had worked in the team making the nuclear bomb during World War 2, so he was an expert in nuclear and atomic chemistry.The half-life refers to the amount of time it takes for half the radiocarbon in a sample of bone or shell or any carbon sample to disappear.Libby found that it took 5568 years for half the radiocarbon to decay.They used pottery and other materials in sites to date 'relatively'.