Mysterious Ring Appears in Antarctic Ice

A mysterious 2 meter-wide ring discovered in Antarctica last month continues to mystify scientists, with some believing the strange feature was caused by a meteorite.

The crater was discovered by German scientist Christian Müller as he conducted an aerial survey of Antarctica's King Baudouin Ice Shelf on December 20, 2014.  "I looked out of the window, and I saw an unusual structure on the surface of the ice," Müller said in a video.  "There was some broken ice looking like icebergs, which is very unusual on a normally flat ice shelf, surrounded by a large, wing-shaped, circular structure."

He told the Daily Mail that he had never seen anything like it before.

Satellite images suggest the possible impact crater may be at least 25 years old.  Still, some scientists aren't convinced the ring was caused by a crater because it would have taken a massive space rock -- and a huge explosion -- to create such a large crater.

"A very large explosion would have caused a 2-kilometer-wide crater — much larger than anything detected impacting Earth in recent history," Peter Brown, director for the Centre of Planetary Science and Exploration at the University of Western Ontario told LiveScience.  "So the feature seen is almost certainly not due to any meteorite impact."

Glaciologists who pored over the newly discovered feature think the crater resembles an ice doline — a sinkhole-type pit that appears when meltwater lakes suddenly drain from their bottoms.

The collapsed circles of ice commonly appear in West Antarctica and Greenland, where prodigious surface melting results in scores of lakes, but ice dolines aren't widely known even among glaciologists.