A Revolution in Archaeology

Studying our ancestors has always fascinated humans, at least since the time of the Romans and Greeks. Eventually, we even gave it a name: Archaeology. But for most of history, we had a hard time dating ancient objects we found and could only predict their relative ages based on whether they were buried in upper or lower layers. A key discovery in 1946 was about to change that and launch a revolution in archaeology.

That discovery was radiocarbon dating, made by chemist Willard Libby. Libby realized that carbon, a chemical element present in every living being, has two different isotopes, carbon-12 and carbon-14, that behave differently but predictably, and that this could be used for dating. The most abundant isotope, carbon-12, remains stable in the atmosphere. On the other hand, carbon-14 is radioactive and decays into nitrogen-14 over time. Every 5,730 years, half of the carbon-14 decays.

By comparing the ratio of carbon-12 to carbon-14, scientists can estimate the approximate date when an organism died. This method helped disprove several previously held beliefs, including the notion that civilization originated solely in Europe and spread elsewhere. By dating man-made artifacts from Europe, the Americas, Asia, Africa, and Oceania, archaeologists established that civilizations developed independently in many parts of the world.

Radiocarbon dating does have limitations, as carbon-14 completely decays after 50,000 years, making it useful only for dating materials younger than that. Other methods have been developed for older samples. Nevertheless, its discovery was so significant that it was called a “revolution in archaeology,” leading to increased investment in excavation and efforts to better understand our past.

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