radiocarbon dating

American  

noun

1. the determination of the age of objects of organic origin by measurement of the radioactivity of their carbon content.

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radiocarbon dating British  

noun

1. Also called: carbon-14 dating.  a technique for determining the age of organic materials, such as wood, based on their content of the radioisotope ¹⁴ C acquired from the atmosphere when they formed part of a living plant. The ¹⁴ C decays to the nitrogen isotope ¹⁴ N with a half-life of 5730 years. Measurement of the amount of radioactive carbon remaining in the material thus gives an estimate of its age

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radiocarbon dating Scientific  

1. A technique for measuring the age of organic remains based on the rate of decay of carbon 14. Because the ratio of carbon 12 to carbon 14 present in all living organisms is the same, and because the decay rate of carbon 14 is constant, the length of time that has passed since an organism has died can be calculated by comparing the ratio of carbon 12 to carbon 14 in its remains to the known ratio in living organisms.

2. Also called carbon-14 dating

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Closer Look

In the late 1940s, American chemist Willard Libby developed a method for determining when the death of an organism had occurred. He first noted that the cells of all living things contain atoms taken in from the organism's environment, including carbon; all organic compounds contain carbon. Most carbon consists of the isotopes carbon 12 and carbon 13, which are very stable. A very small percentage of carbon, however, consists of the isotope carbon 14, or radiocarbon, which is unstable. Carbon 14 has a half-life of 5,780 years, and is continuously created in Earth's atmosphere through the interaction of nitrogen and gamma rays from outer space. Because atmospheric carbon 14 arises at about the same rate that the atom decays, Earth's levels of carbon 14 have remained fairly constant. Once an organism is dead, however, no new carbon is actively absorbed by its tissues, and its carbon 14 gradually decays. Libby thus reasoned that by measuring carbon 14 levels in the remains of an organism that died long ago, one could estimate the time of its death. This procedure of radiocarbon dating has been widely adopted and is considered accurate enough for practical use to study remains up to 50,000 years old.

Etymology

Origin of radiocarbon dating

First recorded in 1950–55

Example Sentences

Researchers supplied the model with a 1,000-year earthquake history reconstructed from geological evidence, including radiocarbon dating, tree ring records, and historical observations of ground ruptures.

From Science Daily • Jun. 18, 2026

The team used radiocarbon dating, which looks at how a special form of carbon changes over time, to work out that the structure was 5,000 years old.

From BBC • Jun. 17, 2026

Combined with radiocarbon dating of fabric fragments preserved inside several helmets, the approach allowed researchers to establish a highly accurate age for the artifacts.

From Science Daily • Jun. 8, 2026

The exact burial location of the Beachy Head Woman remains unknown, but radiocarbon dating indicates she died between 129 and 311 AD, aligning with the Roman period in Britain.

From Science Daily • Jan. 25, 2026

After eight half-lives, only 1/256 of the original radioactive carbon remains, which is too little to make a reliable measurement, so radiocarbon dating works only for objects up to forty thousand or so years old.

From "A Short History of Nearly Everything" by Bill Bryson