The New Horizons team just unwrapped a few more presents from under their year-long Christmas tree, and these are gorgeous. Images taken with the Ralph/MVIC instrument after closest approach, from Pluto’s night side. This is my favorite of the set, by far (click to enlarge):
It’s a long exposure, where New Horizons had to slew to track Pluto during the shoot, and you can tell because a couple of star trails are visible a bit right of center, near the top of the image. The terrain is oddly bumpy, like cauliflower cut by glaciers, and the atmosphere has very distinct layers.
In close-up, you can see that this also captures another, surprising aspect of Pluto’s atmosphere: fog. In this image, you can see shadows cast by the peaks through the fog, so clearly, Pluto actually has *weather*.
In fact, all of this — haze layers, fog, glaciation — suggests very strongly that Pluto not only has rudimentary weather, but it even has a sort of hydrological cycle. It’s not a water cycle, obviously — water is as hard as rock on Pluto. More will hopefully be clear as more of the spectrographic data comes in, but it seems to be a cycle acted out by nitrogen and exotic ices. This region is near Pluto’s pole and seems to be analogous to our own polar regions, with surprisingly similar processes at play.
So yeah — Pluto may have lost its official major planet status, but heck, it’s looking more and more like a *world*.