This image from NASA shows an overlay of Mercury’s new topographic map with the areas of Mercury’s pole that are in constant shadow (red) and those previously suggested to contain water-based ice from Earth-based reflected radio imaging from the Arecibo telescope (yellow). Together with other data from the MESSENGER spacecraft, these data support the view that Mercury harbors a significant amount of ice. Image credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington/National Astronomy and Ionosphere Center, Arecibo Observatory.