MESSENGER view of terrain near Mercury's north pole
A wide-angle camera view of terrain near Mercury's north pole, taken on MESSENGER's first orbit, shows an area blanketed by secondary impact craters, craters that formed when ejecta from a nearby, larger impact crashed into the ground. Only the sharp-rimmed craters are "primaries." The view is close to the north pole so the Sun is nearly on the horizon, throwing long shadows and failing to shine into the bottoms of craters. The image covers an area about 84 kilometers square.