Astronomers find Saturn's magic circle

Published on Wednesday 7 October 2009 21:32

A GIANT ring around Saturn that dwarfs all the planet's others has been discovered by astronomers.

The faint ring has remained hidden until now, but is enormous, extending more than seven million miles from the planet. Unlike Saturn's "flat" rings, the new belt resembles a thick halo of material. Its vertical height is about 20 times the planet's diameter (74,897 miles)

The ring, made from ice and dust particles, was spotted by the Spitzer space telescope which captured its infrared glow. It is associated with one of Saturn's moons, Phoebe, which is believed to supply it with material.

The discovery by US scientists, reported in the journal Nature, may help to solve an age-old riddle concerning one of Saturn's moons. Iapetus has one side that is bright while its other face is strangely dark. Scientists believe the dark side may be due to dusty material from the outer ring slamming into its surface. Iapetus and the outer ring circle Saturn in opposite directions, so debris shed by the ring is likely to collide with the moon.