Some of the most spectacular images ever of Saturn鈥檚 enigmatic rings have been returned by the Cassini space probe.
The pictures were captured using Cassini鈥檚 Ultraviolet Imaging Spectrograph (UVIS) instrument and have been colour-enhanced to illustrate the different materials that lurk within the planet鈥檚 famous discs. They were taken on 30 June shortly before the spacecraft slipped into orbit around the planet by drifting between two of its rings.
Astronomers at the University of Colorado in Boulder, who analysed the images, say they confirm that Saturn鈥檚 rings get dustier and icier towards the edge. The dust and rocky debris found in Saturn鈥檚 rings is thought to be made of silicates and organic materials, while the ice is likely to be a mixture of water and other substances such as ammonia.
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One of the images shows the planet鈥檚 middle ring, known as the A ring, in impressive detail. The dust-strewn interior of the ring is coloured red but the less dusty, more dense ice-filled regions towards the edge are shown in turquoise. The thin red band towards the edge of Saturn鈥檚 A ring is a 325-kilometre void known as the Encke gap.
Colliding comets
Another picture shows the point at which two of Saturn鈥檚 inner rings, the C ring and the B ring merge. This also reveals a general pattern from dusty 鈥渞ed鈥� inner bands to 鈥渂lue鈥� ice-rich outer bands within the rings.
Scientist believe Saturn鈥檚 rings formed a few hundred million years ago when debris from colliding comets and moons was drawn into orbit around the planet by its gravitational influence.
Debris varies in size from tiny dust particles to boulders 10 metres across. The rings extend more than 190,000 kilometres but are just 1.5 kilometres thick.
Studying Saturn鈥檚 rings could help scientists understand of the formation of Solar System itself, as the rings are thought to provide a miniature model of the dust and ice bands that circled the Sun before the planets coalesced.