Cassini sees 'snowball fight' in Saturn ring

Scientists working on the Cassini probe have witnessed small clumps of ice ploughing through one of the gas giant’s main rings - its F-ring.
As they plunge through, the km-sized ice balls leave glittering trails behind them referred to as mini-jets.
Some of these collisions trace quite exotic shapes in the F-ring that look like barbs on a harpoon.
The research has been presented here at the European Geosciences Union (EGU) meeting in Vienna, Austria, by Carl Murray, a Cassini imaging team member based at Queen Mary University of London, UK.
The F-ring is the outermost of Saturn’s main rings. It is located 3,000km beyond the bright A-ring and has a circumference approaching 900,000km.
The Cassini imaging team had been watching the 40km-wide Prometheus moon dance along the edge of this ring for some time.
The moon’s gravitational perturbations regularly produce channels and ripples in the F-ring, and it was known some of the disturbed ice particles could clump together. But it was assumed collisions or tidal forces in their orbit around Saturn would soon break these clumps apart.