It is still more than a year before the MESSENGER spacecraft goes into orbit around Mercury. But along with images taken by Mariner 10 more than thirty years ago that observed less than half of Mercury’s surface, images taken during the three flybys of MESSENGER were enough for nearly complete spacecraft images of the planet’s surface. For the first time, we have a nearly complete global map of the surface of Mercury taken in visible light. That would be cool enough: the map is also going to be useful when MESSENGER goes into orbit around Mercury, which is when it can really start studying the planet.
By the way, I can’t help but be drawn by the dark band that seems to span the whole planet in the north-south direction. Anyone know what it is?