ore than 13,000 years ago, North America was inhabited by the Clovis, a prehistoric Paleo-Indian culture known for advanced stone tools, scientists believe. Then, the evidence suggests, the entire culture vanished — seemingly overnight.

For a long time, scientists speculated that a massive asteroid slammed into the planet, causing bursts of cold air to blanket the continent and triggering an icy glacial period known as the Big Freeze. The hypothesis went that the Clovis, unprepared for the sudden temperature drop, quickly died out. 

Now, according to Science Daily, a team of researchers from 14 academic institutions are arguing that the big impact never happened. "There's no plausible mechanism to get airbursts over an entire continent," said researcher Mark Boslough, a physicist. "For this and other reasons, we conclude that the impact hypothesis is, unfortunately, bogus."

Boslough argues that the Clovis didn't die as suspected, but rather made the transition to Folsoms, another Paleo-Indian culture, sometime between 9000 B.C. and 8000 B.C. "Just because a culture changed from Clovis to Folsom spear points didn't mean their civilization collapsed," says Boslough. "They probably just used another technology. It's like saying the phonograph culture collapsed and was replaced by the iPod culture." (Via Science Daily, Science 2.0)