In 2005 NASA's Deep Impact spacecraft launched an impactor into Comet Tempel 1 in an effort to study its composition. Another spacecraft, Stardust–NExT, caught up with the comet on Monday and from a mere 178 kilometers away captured dozens of images that reveal changes in Tempel 1's surface in the past six years. Between the two visits the comet had completed one trip around the sun.

The montage above includes images collected by Deep Impact [top right] and Stardust–NExT [bottom right]. Scientists think that cliffs, illustrated with yellow lines to the right, are being eroded back to the left in this view. The cliffs appear to have been worn away by as much as 20 to 30 meters in some places since 2005. The box shows depressions that have merged together over time, also as a result of erosion caused by volatile substances evaporating from the comet. The image at top left is a wider shot of Tempel 1 taken by Deep Impact.