A comet which hit Earth 13,000 years ago triggered a mini ice age, scientists believe.
A team from the University of Edinburgh say that ancient symbols they have examined, which are carved into stone at an archaeological site in Turkey, tell the story of a devastating comet impact.
Evidence from the carvings, made on a pillar known as the Vulture Stone, suggests that a swarm of comet fragments hit the Earth in around 11000 BC.
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One image of a headless man is thought to symbolise human disaster and extensive loss of life.
The site is at Gobekli Tepe in southern Turkey, which experts now believe may have been an ancient observatory.
Computer software was used to match carvings of animals – interpreted as astronomical symbols – to patterns of stars and pinpoint the event to 10950 BC.
Other evidence for the impact from a Greenland ice core suggests roughly the same time frame.
The cataclysm ushered in a cold climate lasting 1,000 years and is likely to have resulted from the break-up of a giant comet in the inner solar system.
“It appears Gobekli Tepe was, among other things, an observatory for monitoring the night sky,” said lead researcher Dr Martin Sweatman.
“One of its pillars seems to have served as a memorial to this devastating event – probably the worst day in history since the end of the Ice Age.”
The carvings appear to have remained important to the people of Gobekli Tepe for millennia, indicating an event that had a very serious and long-lasting impact, said the scientists whose findings are published in the journal Mediterranean Archaeology and Archaeometry.