Mask of Vaikuntha Vishnu, late 5th century. Learn more about 5th century masks
A method of determining the objective age of carbon-based materials by measuring the amount of carbon-14, formed when the nitrogen of radiocarbon decays, against an internationally used standard reference. William F Libby is credited with developing the method in 1946. It is used widely in disciplines such as archaeology and other natural sciences to determine the age of biological specimens and artefacts.