March 29 (UPI) -- A merger of many ice volcanoes form Pluto 's two mane mountains, a study published Tuesday in Nature Communications reveals -- and what they've found suggests the planet is an ocean world, despite its great distance from the Sun. Pluto has two mountains, Wright Mons and Piccard Mons, which scientists suspected were volcanoes that spewed icy slush in a cryovolcanic eruption process instead of molten rock. Though no cauldron-like caldera could be seen, new analysis of images and