Caption: The image, one of the closest taken of comet Hartley 2 by NASA's EPOXI mission, shows many features across the comet's surface. The length of the comet is equal to the distance between the Capitol building and the Washington Monument in Washington. There are two obvious regions of jet activity associated with rough terrain. The smooth surface in the middle is lower than the rest of the comet and may accumulate fine-grain dust.
The image was taken by EPOXI's Medium-Resolution Instrument on Nov. 4, 2010. The sun is to the right.