Via Wired Magazine:
On Thursday the agency released the best images so far of Pluto’s moon Charon. Its surface features indicate some lively geologic activity. One half of the planet (let’s refrain from imposing our Terran notions of “north” and “south” on this alien world) is craggy and mountainous, with evidence of landslides.
The landscape below the canyon is a lot smoother than above. Fewer craters indicates that Vulcan Planum, as the New Horizons team is calling it, is probably a lot younger. Nobody expected active geology on Pluto or its satellites, so scientists are still working out what causes the subsurface roiling. But in Charon’s case, they suspect cryovulcanism. That’s right: ice volcanoes. A layer of heavy rock presses downward onto a thick layer of frozen water. Sandwiched against rock below, that ice ruptures through Charon’s surface where the stuff flows like lava.