Context
∙ Radiocarbon dating helped establish the age and authenticity of the famous Dead Sea.
Radiocarbon Dating
∙ Radiocarbon dating, or carbon-14 dating, is a scientific method that can accurately determine the age of organic materials.
∙ It was developed in the late 1940s by Willard Libby, the technique is based on the decay of the carbon-14 isotope.
How does radiocarbon dating work?
∙ It starts with cosmic rays—subatomic particles of matter that continuously rain upon Earth from all directions.
∙ When cosmic rays reach Earth’s upper atmosphere, physical and chemical interactions form the radioactive isotope carbon-14.
∙ Living organisms absorb this carbon-14 into their tissue. Once they die, the absorption stops, and the carbon-14 begins very slowly to change into other atoms at a predictable rate.
∙ By measuring how much carbon-14 remains, scientists can estimate how long a particular organic object has been dead.
What are the limitations of carbon-14 dating?
∙ Radiocarbon dating works on organic materials up to about 60,000 years of age.
∙ Conventional radiocarbon dating requires samples of 10 to 100 grams (0.35 to 3.5 ounces) of an object, depending on the material in question.
∙ Newer forms of dating can use much smaller amounts, down to 20 to 50 milligrams or 0.0007 to 0.0018 ounces.
∙ Radiocarbon samples are also easily contaminated, so to provide accurate dates, they must be clean and well-preserved.
Has radiocarbon dating improved over the years?
∙ Technological and analytical advances have made radiocarbon dating faster and much more precise—and expanded its range of uses by reducing the size of the sample needed.
∙ The latest form of radiocarbon dating, called accelerator mass spectrometry, needs samples of only 20 to 50 milligrams however, it is also more expensive.
∙ Another newer development is Bayesian statistical modeling, which applies probability analytics to radiocarbon dates, which always involve an error margin.
What discoveries has carbon-14 testing revealed?
∙ The breakthrough introduced a new scientific rigor to archaeology, allowing archaeologists to put together a history of humans across the world.
∙ Carbon dating has helped us reveal how our bodies work, to understand the climate of the Earth and reconstruct its history, and to track the sun’s activity and the Earth’s magnetic fields.
∙ Radiocarbon dating was also instrumental in the discovery of human-caused climate change, as scientists used it to track the sources of carbon in the atmosphere over time.
