Subsurface Ocean May Have Rolled Pluto Over

Researchers believe they have spotted evidence of what could be the most remote body of water in our solar system: A vast ocean below the surface of Pluto. In a study published in Nature, researchers explain that the 600-mile-wide Sputnik Planitia region, a plain that is part of the heart-shaped feature on the dwarf planet's surface, appears to have accumulated so much ice over millions of years that it caused Pluto to flip over and reorient itself, Space.com reports. The researchers believe the plain was created by an asteroid impact that weakened the crust, causing nitrogen ice to rise from a subsurface ocean in quantities big enough to eventually roll the planet over.

Cracks on Pluto's surface support the rolling-over theory. "It's like freezing ice cubes," researcher James Keane says in a University of Arizona press release. "As the water turns to ice, it expands. On a planetary scale, this process breaks the surface around the planet and creates the faults we see today." MIT News reports that researcher Richard Binzel says readings from the New Horizons spacecraft revealed that Pluto is still a little warm, and the measurements point to a subsurface ocean. "It’s not a liquid, flowing ocean, but maybe slushy," says Binzel, who describes Pluto as "hard to fathom on so many different levels." (What looked like snails on Pluto's surface were actually dirty icebergs.)