NASA Probe Passes 'Snow Globe' Comet

Hartley covered with golf ball-size 'snowballs'
By Matt Cantor,  Newser User
Posted Nov 19, 2010 8:28 AM CST
This image provided by NASA shows a Nov. 4, 2010 image from NASA's EPOXI mission spacecraft showing part of the nucleus of comet Hartley 2.   (AP Photo/NASA)
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(Newser) – NASA's Deep Impact probe soared past a comet earlier this month, revealing the mass to be peppered with "snowballs," the BBC reports. Comet Hartley, encountered some 14 million miles from Earth, "looks like a 'snow globe' that you've just simply shaken,” said a scientist. Another noted that the largest ice particles surrounding it “are at least the size of a golf ball and possibly up to the size of a basketball.”

But the "snowballs" are not big chunks of ice; instead, they're made up of tiny particles no bigger than one to 10 microns—a measurement roughly equivalent to “the thickness of our hair,” said another expert. “What we're seeing are fluffy aggregates of very small pieces of ice. They're akin more to a dandelion puff than an ice cube.” The Deep Impact probe will complete its observation of the mile-long, peanut-shaped comet at the end of next week; in total, it will have taken some 122,000 photos.

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