Willard Libby from the University of Chicago put it to the test.By 1949, he had published a paper in Science showing that he had accurately dated samples with known ages, using radiocarbon dating.A decade after Douglass's big discovery, two Berkeley scientists took the first step towards an alternative way to date floating chronologies and indeed any other "once-living" thing. Also known as radiocarbon, carbon-14 is a radioactive isotope of carbon with an atomic nucleus of six protons and eight neutrons. They discovered its half-life, or the time it takes for its radioactivity to fall by half once the living thing dies, is 5,730 years (give or take 40).
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In 1929, with a beam from Show Low, Arizona, Douglass was able to bridge the gap for the first time ever.
Dates were assigned to Southwestern ruins with certainty.
The first single-celled organisms on Earth did not appear until about a billion years later.
Dinosaurs did not appear until 230 million years ago, and ruled the planet for 135 million years.
The first modern humans did not evolve in Africa until about 1.8 million years ago.
The time between then and now is just a single tick on the universe's clock.
If a Bigtooth Maple were cut down on Mount Lemmon in 2016 and it had 400 rings, you would know the tree started growing in 1616. What if it's been used to build a home or a ship or a bonfire?
The rings could still tell how many years the tree lived, but not necessarily when. He set out on a series of expeditions across the southwest to bridge the gap between contemporary wood and wood beams from the ruins of civilizations long gone.
Dendrochronology and radiocarbon dating have intertwined histories, she explains, with roots firmly planted at the UA.