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At the end of the Permian period, around 250 million years ago, a huge proportion of the life on our planet was wiped out. The cause of this mass extinction has been a subject of debate for many years.
Now, new geological evidence suggests that the "great dying" was caused by an asteroid slamming into the Earth. The clue comes from dozens of tiny mineral grains found in ancient rocks in Antarctica.
The tiny bits of rock bear all the hallmarks of being from a stony meteorite. Asish Basu, a geochemist at the University of Rochester, New York, believes the fragments fell to Earth at the end of the Permian period, 250 million years ago, when about 90% of marine life and 70% of land species vanished. If this is the case, it would be the second time an asteroid or comet has caused a mass extinction on Earth.
"It appears to us that the two largest mass extinctions in Earth history ...were both caused by catastrophic collisions with chondritic meteroids," Basu, and four colleagues from other US universities, write in the journal Science.
More info: Science
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