And you thought you were having a crap Friday: 13,000 years ago, a comet may have collided with earth in the Great Lakes region, creating a 1,000-year-long cold spell that wiped out the Clovis culture of humans in North America.
For years, the disappearance of North America's Clovis culture was attributed either to rapid climate change or a sudden uptick in Clovis hunting practices that wiped out the 35 genera of animals they subsisted on. But similar climate changes of the time hadn't resulted in mass extinctions, and the ethnographic record doesn't support such a rapid change in hunting habits among Clovis humans.
Instead, Douglas Kennett and 25 other researchers from the University of Oregon think that a major comet collision triggered the change. The new hypothesis is based on a thin black layer of soil retrieved at over 50 North American sites. This black soil possesses magnetic grains of iridium, thought to have extraterrestrial origins, along with metallic and carbon spherules, as well as melted charcoal, which remained after catastrophic, continent-wide fires swept the land in the comet's wake.
