What is the radioactive half-life of carbon 14?
Carbon-14 has a 5,730 year half-life, meaning that every 5,730 years, about half of an artifact's C-14 will have decayed into the stable (non-radioactive) isotope nitrogen-14.
Its presence in organic materials is the basis of radiocarbon dating to date archaeological, geological and hydrogeological samples. Plants fix atmospheric carbon during photosynthesis, so the level of 14C in plants and animals when they die approximately equals the level of 14C in the atmosphere at that time. However, it decreases thereafter from radioactive decay, allowing the date of death or fixation to be estimated.
Radiocarbon dating is used to determine the age of carbonaceous materials up to about 60,000 years old. After about 50,000- 60,000 years (or approximately nine half-lives) the amount of C-14 remaining is generally too small to measure reliably.