An early North American culture that vanished off the face of the earth 12,900 years ago — along with several species of prehistoric animals — may have been made extinct because of a devastating comet strike.
The disappearance of the Clovis culture, named after a distinctive Paleo-American spear point, has long been blamed on the planet's emergence from the Ice Age.
Now, however, it has emerged that one of the biggest calamities man has ever faced may have been caused by an apocalyptic strike by a comet, which broke into giant fragments, smashing into Earth.
Researchers from the University of Oregon say that they have found nanodiamonds scattered throughout North America in sediments, dating from the era that this extinction took place.
The scientists say the discovery shows that a high-pressure, high-temperature event such as a comet impact may have taken place there, causing what is known as the Younger Dryas cooling period.
In a paper published in the journal Science, Douglas J. Kennett said that the discovery gave scientists a "big idea" about what had happened.
"It's a hypothesis. Basically, there's a suite of data that suggests that something like this occurred, but it still needs to be tested," he said.