Moon-like surface of Mercury

Moon-like surface of Mercury

Fig. 6.7 . After passing the dark side of Mercury, the Mariner 10 spacecraft looked back at the sunlit hemisphere of the planet and photographed these images that have been assembled into a mosaic. It shows large tracts of smooth plains, which may be due to extensive volcanism. Partially visible along the day-night terminator (left) is half of the Caloris basin (above center toward the top), a gigantic multi-ringed impact scar. (Courtesy of NASA/JPL.)

Copyright 2010, Professor Kenneth R. Lang, Tufts University