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(Journalist)
– A mass extinction event that struck Earth 359 million years ago still has scientists scratching their heads. Was it volcanic eruptions? Meteorites? Gamma-ray bursts? A new article examines another possible culprit: the explosion of stars. Researchers at the University of Illinois say the evidence hidden in the rocks coincides with the effect of at least one supernova 65 light years from Earth at the end of the Devonian, reports Futurism. By analyzing the ancient plant spores in the rocks, they found signs of severe ultraviolet sunburn – exactly what you would expect from long-term ozone depletion in the atmosphere. “Large-scale volcanism and global warming can also destroy the ozone layer, but the evidence for these is inconclusive for the time interval in question,” senior author Brian Fields said in a statement. .
Today, his team is researching what Fields calls “the smoldering weapons of a nearby supernova”: the radioactive isotopes samarium-146 and plutonium-244 in fossils and rocks deposited during the extinction. “None of these isotopes occur naturally on Earth today, and the only way to get there is through cosmic explosions,” says co-author Zhenghai Liu. Interesting side note: the team considers multiple explosions to be possible as huge stars often exist in clusters and can explode if triggered by a supernova in the group, Forbes Remarks. But Fields sees a bigger message in all of this: “Life on Earth does not exist in isolation,” he says. “We are citizens of a larger cosmos, and the cosmos intervenes in our lives – often imperceptibly, but sometimes fiercely.” (Read more stories of mass extinction.)
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