The newer bones somehow ended up in the network’s Dinaledi Chamber some 236,000 to 335,000 years ago.That’s the conclusion of an international research team. He’s a paleoanthropologist in South Africa at the University of the Witwatersrand in Johannesburg.
This raises the surprising possibility that both our species and this other hominid might have coexisted.
The newly studied fossils come from a species that has been dubbed Homo naledi. Estimates had put them at between 900,000 and 1.8 million years old.
As soon as a living organism dies, it stops taking in new carbon.
The ratio of carbon-12 to carbon-14 at the moment of death is the same as every other living thing, but the carbon-14 decays and is not replaced.
However, the principle of carbon-14 dating applies to other isotopes as well.
Potassium-40 is another radioactive element naturally found in your body and has a half-life of 1.3 billion years.
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Wiens has a Ph D in Physics, with a minor in Geology.
His Ph D thesis was on isotope ratios in meteorites, including surface exposure dating.
Other useful radioisotopes for radioactive dating include Uranium -235 (half-life = 704 million years), Uranium -238 (half-life = 4.5 billion years), Thorium-232 (half-life = 14 billion years) and Rubidium-87 (half-life = 49 billion years).