Pluto could harbour 'slushy underground ocean'
A frozen area of Pluto, known as the 'heart' may harbour a slushy ocean between 150 and 200 km beneath its surface, NASA scientists say. This could explain why part of the region - Pluto's most prominent feature - remains securely aligned with Charon, its largest moon. Its believed the central area contains as much water as all of Earth's seas.