Radioactive carbon dating accuracy

Carbon dating: How scientists hack radiation to age ancient artefacts

Radiocarbon dating also referred to as carbon dating or carbon dating is a method for determining the age of an object containing organic material by using the properties of radiocarbon , a radioactive isotope of carbon. The method was developed in the late s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon 14 C is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting 14 C combines with atmospheric oxygen to form radioactive carbon dioxide , which is incorporated into plants by photosynthesis ; animals then acquire 14 C by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of 14 C it contains begins to decrease as the 14 C undergoes radioactive decay. Measuring the proportion of 14 C in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calculate when the animal or plant died. The older a sample is, the less 14 C there is to be detected, and because the half-life of 14 C the period of time after which half of a given sample will have decayed is about 5, years, the oldest dates that can be reliably measured by this process date to approximately 50, years ago in this interval about In , Libby received the Nobel Prize in Chemistry for his work. Research has been ongoing since the s to determine what the proportion of 14 C in the atmosphere has been over the past 50, years. The resulting data, in the form of a calibration curve , is now used to convert a given measurement of radiocarbon in a sample into an estimate of the sample's calendar age.

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Radiometric dating , radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon , in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. Together with stratigraphic principles , radiometric dating methods are used in geochronology to establish the geologic time scale.

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At least to the uninitiated, carbon dating is generally assumed to be a sure-fire way to predict the age of any organism that once lived on our planet. Without understanding the mechanics of it, we put our blind faith in the words of scientists, who assure us that carbon dating is a reliable method of determining the ages of almost everything around us. However, a little more knowledge about the exact ins and outs of carbon dating reveals that perhaps it is not quite as fool-proof a process as we may have been led to believe.

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Willard Libby and Radiocarbon Dating

Dating is everything in archaeology. Exciting discoveries of ancient burial sites or jewellery might make headlines, but for scientists, this kind of discovery is only meaningful if we can tell how old the artefacts are. So when chemist Willard Libby developed radiocarbon dating in , it was a breakthrough for archaeology and he was awarded a Nobel prize for his achievement.

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