Here's why:
* Radioactive Decay: Carbon-14 is a radioactive isotope of carbon that decays at a known rate.
* Carbon Cycle: Living organisms constantly take in carbon from the environment. This includes carbon-14, which is present in a relatively constant proportion to stable carbon isotopes.
* Decay After Death: When an organism dies, it no longer takes in carbon. The carbon-14 in its remains begins to decay, and the amount of ¹⁴C decreases over time.
* Half-Life: The half-life of carbon-14 is approximately 5,730 years. This means that after 5,730 years, half of the original amount of ¹⁴C in a sample will have decayed.
* Radiocarbon Dating: By measuring the remaining amount of ¹⁴C in a sample, scientists can determine how long ago the organism died. This method, known as radiocarbon dating, is used to date organic materials up to about 50,000 years old.
Other isotopes can be used for dating purposes, but carbon-14 is particularly useful for organic matter due to its presence in all living things and its relatively short half-life.
