Phoebe is 'cosmic time capsule'

Despite Phoebe's bumpy topography, the moon has a fairly round shape (Nasa/JPL/Space Science Institute)

Saturn's moon Phoebe is almost certainly a primordial object similar to those that served as the building blocks of planets in our Solar System.

That is one of the findings of the Cassini space probe's recent flyby of the tiny impact-battered satellite.

Scientists believe bodies like Phoebe were plentiful in the outer Solar System about 4.6 billion years ago.

Phoebe is like no other Solar System object that has ever been subjected to detailed astronomical observation.