Giant Space Loofah? No, Hyperion

It may have the look of a giant sponge, but this is Saturn's moon Hyperion, as pictured by the Cassini spacecraft.

The US-European probe has just made a flyby of the satellite, crossing its surface at a distance of just 500km.

The surface is speckled with impact craters which scientists say have been modified by some process, not yet understood, to create the strange look.

Much of the interior of Hyperion is empty space, suggesting it is little more than a pile of space rubble.