radiocarbone

Radiocarbon, or radiocarbon dating, refers to the use of the radioactive isotope 14C to determine the age of organic materials. 14C is produced in the upper atmosphere by cosmic rays converting nitrogen-14 to 14C, which becomes carbon dioxide and enters the biosphere through photosynthesis and feeding.

Once an organism dies, exchange with the environment ceases and the 14C decays to nitrogen-14 at a known rate. The remaining 14C/12C ratio is used to estimate the time since death, typically up to about 50,000 years, beyond which the signal becomes too faint.

Developed by Willard Libby in the late 1940s, radiocarbon dating revolutionized archaeology and geology. Modern practice includes accelerator mass spectrometry (AMS), which counts 14C atoms directly, using much smaller samples, and improved calibration curves that track historical variations in atmospheric 14C.

Dating requires careful sample preparation and contamination control. Measurements are calibrated against independent records (tree rings, corals) to convert radiocarbon years to calendar dates, using standard calibration curves such as IntCal. Awareness of reservoir effects, contamination, and material-specific biases is essential in interpretation. Radiocarbon dating is widely used in archaeology, geology, paleoclimatology, and art authentication, with typical practical range up to 50,000 years.