UK Daily Mail 
April 1, 2011
Scientists have traced ripples in the ring systems of Saturn and Jupiter back to collisions with comets more than ten years ago.
The ripples detected in Saturn’s rings date back to 1983, while the disruption to Jupiter’s lesser-known rings was caused in 1994, Nasa researchers believe.
The culprit, in the case of Jupiter, was comet Shoemaker-Levy 9, whose debris cloud hurtled through the planet’s thin ring system during a kamikaze course into the planet in July 1994.
Saturn’s ripples were caused by a similar object – likely another cloud of comet debris – plunging through the inner rings in the second half of 1983.