THE broken body of a former moon turns out to be the source of Saturn’s faint G ring, a mystery since its discovery in 1979.
Lying just beyond the planet’s main set of rings, the G ring has no moon nearby to feed it with debris or stop its dust from dispersing, so its existence has puzzled astronomers. Now images captured by the have revealed a bright arc at the G ring’s inner edge that is thought to consist of remnants of a former moon in chunks up to a metre in diameter (Science, ).
As they are bombarded by micrometeorites, dust flies off these chunks and spreads out to form the ring, says team leader Matthew Hedman of Cornell University in Ithaca, New York.
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