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Thursday, February 21, 2019

Scientists Discover Hidden Asteroid Crater Under a Mile of Greenland Ice

 

Scientists have discovered a colossal impact crater hidden under a mile of ice in northwest Greenland, according to a new study in Science Advances that could have major repercussions for several scientific fields.

This is exactly the kind of news we need, but the mainstream media simply does not cover. I found about this on the radio today morning, none of the print media here or in India mentioned it. The crater was actually first detected in July 2015, but only now have scientists been able to verify the discovery. It’s the first time that a crater of any size has been found under a continental ice sheet. The enormous cavity is bigger than London and ranks among the 25 largest impact craters on Earth.

The crater stretches for 31 kilometers (19 miles) underneath Hiawatha Glacier, and was blasted into existence by a mile-long iron asteroid that unleashed the equivalent of 700 one-megaton nuclear bombs of energy upon impact. It is the first impact crater ever detected under Greenland’s ice cover, and ranks among the top largest 25 impact formations known on Earth.

The discovery has been in the making since 2015, when lead author Kurt Kjær, a geochemist at the University of Copenhagen, noticed a weird depression under the glacier in maps made by NASA’s Operation IceBridge.

As a bonus twist, the discovery may shed light on the heated scientific debate over what catalyzed the Younger Dryas, a period of sudden global cooling in the Northern Hemisphere from 12,800 to 11,700 years ago. A 2007 study suggested that the Younger Dryas could have been set off by an asteroid impact that plunged the hemisphere into ecological disarray and helped wipe out megafauna species like mammoths.

Rebuttals to this idea abounded, and the Hiawatha Glacier crater could end up being totally unrelated to the Younger Dryas. But for now, it’s one of many intriguing questions that Kjær’s team hope to pursue in future research.

“This study suggests several avenues for further research into both the nature and age of the Hiawatha impact crater and other possible subglacial impact craters,” the authors concluded in the study. “In particular, an improved geochronology for this impact event awaits the discovery and analysis of additional samples, from either within the crater itself or the surrounding area.”

 

 

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