Enormous glacier calves in largest Arctic event seen in 48 years

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Aug. 23 2010 7:00 AM

Enormous glacier calves in largest Arctic event seen in 48 years

The NASA Earth-science satellite Earth Observing-1 has returned another amazing picture: the calving of Petermann Glacier off Greenland. The break happened on August 5, and this shot was taken 11 days later:

eo1_petermanglacier

Phil Plait Phil Plait

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!  

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The fjord is to the bottom, and the ice island that broke off is moving to the upper left. The picture is so clear and detailed that the scale is hard to determine by eye, but when you grasp it it's mind-boggling: that chunk of ice is more than 25 kilometers long. That's 15 miles.

Having a hard time grokking that? Here's a picture of New York City to the same scale:

nyc

I labeled Manhattan and Central Park, which you can barely see. That big chunk of ice just off the north end of the remaining glacier is as big as downtown Manhattan itself. The big island that broke off is roughly 1/4 the size of the entire glacier.

The obvious question is: is this an indication of global warming? Not necessarily. Glaciers calve all the time. And even though this is the largest such fracturing seen in the Arctic since 1962, we can't extrapolate too much from it... though scientists can use this event to understand how dynamic glaciers can be. With the sea ice thinning -- and it certainly is -- the more we know, the better.

NASA has more images of the calving, though none as detailed or as hauntingly beautiful as this one. That page also has links to more information about this massive and stupendous event.

Image credit: the NASA EO-1 team and the United States Geological Survey.