A new study claims that a meteor or asteroid crashed into Quebec 12,900 years ago, ushering in an era called the "Big Freeze."
The climate cooling caused by the crash saw the Earth develop a chillier and drier climate, the authors say.
This massive incident may have led to the growth of modern civilization, including the disappearance of various large animals like mastodons, the growth of sedentary farming communities and a large change in the diets of our ancestors.
Dartmouth researchers have posited their revolutionary theory in the face of a long-held belief that the cooling climate was due to the melting of the North American ice sheet.
The icy water was said to have affected oceans, which in turn changed weather patterns.
Yet these scientists say that this, in fact, was not the case.
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They reached their conclusion by studying pieces of molten rock from an asteroid that crashed into Earth — though the site of impact has still not been found.
"It may well have taken multiple concurrent impacts to bring about the extensive environmental changes of the Younger Dryas [Big Freeze]," said study author Mukul Sharma, in a press release.
"However, to date no impact craters have been found and our research will help track one of them down."
The study was published in the journal Proceedings of the National Academy of Sciences (PNAS).