The pictures transmitted by the Voyagers showed the two giant planets, and their assorted moons and rings, in unprecedented detail.

ECONOMIST: The long arm of the celestial repairman

Belinda and Umbriel, two of Uranus's larger moons, take their names from a poem by Alexander Pope.

ECONOMIST: Today we have naming of parts

Moons that orbit their planet too closely will experience strong tidal heating and a runaway greenhouse effect that would boil away any surface water.

MSN: News editor

By contrast, the data on which Newton and Einstein built their theories were from stars, planets and moons.

ECONOMIST: Physics

Saturn has a network of over 60 moons and as they orbit the planet their gravitational influence sweeps through the rings.

BBC: Saturn's beauty and power

As the moons pass close to - or even through the rings, their gravitational pull tugs waves of the ring particles towards them, twisting and shaping the ring and sweeping paths through them.

BBC: Saturn's beauty and power