As a planet, Pluto was a real dog. Now scientists say there may be something truly fishy about one the little world's three known moons.

Astronomers have announced they have evidence that, despite the bitterly cold conditions on the edge of the solar system, Pluto's moon Charon may have an underground ocean of liquid water, triggering speculation it could harbour marine life.

The water appears to be spewing up through cracks in the surface, producing spectacular geysers that instantly freeze, creating showers of ice.