NASA’s ice sleuths got the better picture (at top) by stitching together two images from New Horizons’ infrared imager. Rather than a flat image, the scientists had a digital cube of data, with cross sections representing a broad swath of the near infrared spectrum. In effect, this let them mute the non-water ice signatures, and amplify that of the water ice. The result is the robust beard of blue on the right.
In the new map, Sputnik Planum—the heart’s left lobe—is still relatively free of water ice. This makes sense given the prevailing hypothesis that Sputnik Planum is basically a gigantic glacier made of nitrogen ice, methane ice, and carbon monoxide. The same stuff is probably behind Pluto’s northern bald spot (keeping with this weird “water-is-hair” metaphor I’ve got going here). Called Lowell Regio, it too is mostly water ice free, though unlike Sputnik Planum, which researchers believe formed from a massive impact, scientists aren’t quite sure why this region is so bare.