Ripples in planetary rings linked to comets

BBC : Mark Showalter of California’s SETI Institute, Matthew Hedman of Cornell University, and their respective colleagues have come up with an explanation for why Jupiter’s and Saturn’s rings appear rippled. Showalter’s team analyzed images of Jupiter’s rings taken by the Galileo and New Horizons spacecraft. Hedman’s team analyzed images of Saturn’s rings taken by the Cassini spacecraft. Their analyses, published yesterday in Science, suggest that the ripples were caused by debris, most likely from a comet, tilting the ring relative to the planet’s equatorial plane and then leaving a spiral pattern behind as it passed through. As time goes by, the ripples become more closely spaced, providing a means to deduce when the original impact occurred.