| Liquid Ocean Discovered on Pluto
The enigmatic dwarf planet has been throwing up no shortage of surprises over the last few years. When NASA's New Horizons spacecraft performed a flyby of Pluto on July 14, 2015, it found, not a barren wasteland, but a world filled with a bewildering array of complex and varied surface features. Now scientists in Japan have determined that Sputnik Planitia - a large ice-covered basin - could be concealing a vast subterranean ocean similar to that found on Europa and Enceladus. While it was previously believed that the temperature required to maintain a liquid ocean would cause the ice to melt, it has since been suggested that a layer of gas above the liquid and below the ice could insulate the two from one another and enable them to co-exist. "To maintain an ocean, Pluto needs to retain heat inside," the researchers wrote. "On the other hand, to maintain large variations in its thickness, Pluto's ice shell needs to be cold." "Here we show... that the presence of a thin layer of