Until recently, this used to be one of my favorite deep space images:
It is a frozen lake in the Ruach Planitia region of Neptune’s Moon Triton: an incredibly distant, dark and desolate world.
OK, the image is still one of my favorites, but on my list of favorites, it’s just been taken over by this one:
That, ladies and gentlemen, is a large (about 30 km) frozen lake (most likely frozen nitrogen), in the Sputnik Planum region of the planet Pluto.
Who would have thought that Pluto, the recently demoted ex-planet, a frozen world at the edge of the solar system, would have such complex climate and such a fascinating geological history?