Since the Dawn spacecraft arrived at Ceres in March of this year, it has slowly been taking high resolution maps of the surface from several different altitudes. After each successive mapping run it moves into a closer orbit of the icy world for a higher resolution glimpse. After two successful mapping runs, we finally have a full high resolution topographic map of Ceres, revealing its cratered surface in unprecedented detail. With a quick look at the map, a couple of things become apparent immediately.  For one, the surface craters are quite deep, and consistent with an icy crust.  The size...