THE mystery of how Saturn’s rings were formed may be solved in 2004, when the spacecraft Cassini is due to arrive. There’s one problem though: the spacecraft won’t be allowed to fly through the denser rings in case it’s hit by a large boulder.
Fortunately, researchers in Norway have devised a way of studying the rings without endangering the spacecraft. The idea is to analyse the V-shaped wakes that boulders leave in the rings’ “dusty plasma”—ionised gases that contain small particles of solid matter.
As the bigger boulders fly through the rings, they leave behind a cone-shaped wake similar…
