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Researchers say they finally know why slabs of glass litter this desert: An ancient, exploding comet

A new study suggests that an ancient, exploding comet is what caused slabs of glass to be strewn across the Atacama Desert in Chile.
A new study suggests that an ancient, exploding comet is what caused slabs of glass to be strewn across the Atacama Desert in Chile.

An ancient fireball that blasted by a massive desert in Chile some 12,000 years ago created slabs of twisted glass that measure up to a foot and a half in length.

That's according to a newly published study that called the objects the "first clear evidence" of glass created by a comet – or comets – exploding at a low altitude just above the Earth's surface.

The explosion likely unleashed "ultrahigh temperatures" that turned parts of the desert's soil into pieces of silicate glass, the study said.

A 2012 study detailed the large collection of glassy slabs strewn across a nearly 50-mile stretch of the Atacama Desert in northern Chile, but researchers were puzzled for years as to how they were created.

Photos of glass slabs from the Atacama Desert in Chile show how the objects were twisted and folded while still molten, researchers say.
Photos of glass slabs from the Atacama Desert in Chile show how the objects were twisted and folded while still molten, researchers say.

One theory suggested they were created during an intense grass fire, but the new peer-reviewed study, published this week in Geology, says that can be ruled out. The glass objects contain minerals often found in extraterrestrial rocks and share some of the same composition as a space rock called Wild 2, a comet examined by NASA on its Stardust mission.

“Those minerals are what tell us that this object has all the markings of a comet,” said Scott Harris of the Fernbank Science Center in Atlanta and a co-author of the study.

The glasses generally take a black or green color and show characteristics of being exposed to extreme temperatures, perhaps in excess of 3,000 degrees Fahrenheit, according to Pete Schultz, an author of the study and a professor at Brown University.

Their shapes show evidence of "sliding, shearing, twisting, rolling, and folding" before they solidified into their current formation, the study said.

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Interestingly, the tentative dating on the glasses' formation coincides with the disappearance of a group of large animals in South America, though researchers say they aren't ready to determine causation just yet.

“It’s too soon to say if there was a causal connection or not, but what we can say is that this event did happen around the same time as when we think the megafauna disappeared, which is intriguing,” Schultz said in a statement.

The study also noted that the cometary explosion might have occurred around the same time that humans inhabited the area.

“It would have been quite a show,” Schultz said.

Follow Jay Cannon of USA TODAY on Twitter: @JayTCannon

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This article originally appeared on USA TODAY: Glass slabs in Chile's Atacama Desert come from comet explosion: Study