Revealed with an ultraviolet camera: the rings of rock and ice that give Saturn its beauty

The Cassini spacecraft has taken the best images of Saturn's rings, using an ultraviolet camera to pick out the vast fields of ice-strewn debris that circle the planet.

The Cassini spacecraft has taken the best images of Saturn's rings, using an ultraviolet camera to pick out the vast fields of ice-strewn debris that circle the planet.

The picture here shows the "A" ring ­ one of Saturn's seven main rings, which starts as a dirty, dust-strewn interior, shown as red and turning turquoise as the ring turns more icy and less dusty.

The red band roughly three quarters of the way out of the "A" ring is known as the Encke gap.

Scientists at the University of Colorado, who analysed the data from Cassini's ultraviolet spectrograph, said the images show that there is more ice and less rocky debris towards the outside of the rings.

Saturn's most stunning feature is its distinctive ring system. All "gas-giant planets" ­ such as Venus ­ have rings but only those around Saturn are clearly visible from Earth.

The rings of Saturn are made up of billions of particles of ice and rock, which vary in size from dots of dust to boulders up to 10 metres across. Astronomers believe that they are remnants of comets, asteroids or moons that have collided and shattered into millions of pieces to be swept around in orbit by Saturn's gravity.

Larry Esposito, the leader of the Colorado team who discovered the "F" ring in 1979 using data from the Pioneer spacecraft, said that the latest images clearly show that rings A, B and C vary in composition.

The ultraviolet spectrograph on board the Cassini spacecraft can show up features up to 60 miles across, roughly 10 times the resolution obtained by the earlier Voyager 2 spacecraft. This is powerful enough to resolve the "Cassini division", discovered by Giovanni Domenico Cassini in the 17th century, which separates the A and B rings of Saturn, showing they are not contiguous features.

Astronomers have speculated aboutSaturn's rings since they were first detected in 1610 by Galileo, who likened them to handles on a vase.

Although they extend out more than 120,000 miles, they are only about a mile thick.