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Stardust Memories
Hunk of rock surrounded by light.Sure, any rock could look this good with the right backlighting.

But to be fair, this is no rock. It’s the central nugget -- or nucleus -- of comet Wild 2, as captured by NASA’s Stardust. The spacecraft was lofted into space in 1997 and glided through the comet’s coma -- the dust and gas cloud surrounding the nucleus -- earlier this year.

And to be honest, the touchups don’t end with the lighting. This is actually a composite of two images recorded by Stardust’s navigation camera during its January 2nd, 2004 “flyby” near the comet. A short exposure showed surface pocks and craters. A longer exposure, taken 10 seconds later, revealed material streaming from the surface.

The pits and craters are scars of billions of years of interplanetary travel. That has meant countless strikes by meteors and “erosion” from gasses that spew from the comet as it nears the sun during every orbit. The nucleus shown here is only about five kilometers wide, but the jets of dust and gas trail behind for millions of kilometers more.


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