Radiocarbon helps date ancient objects — but it’s not perfect

For nearly 70 years, archaeologists have been measuring carbon-14 levels to date sites and artifacts.

Nothing good can last — and in the case of carbon-14, a radioactive isotope found in Earth’s atmosphere, that’s great news for archaeologists.

Over time, carbon-14 decays in predictable ways. And with the help of radiocarbon dating, researchers can use that decay as a kind of clock that allows them to peer into the past and determine absolute dates for everything from wood to food, pollen, poop, and even dead animals and humans. Read more.