A History of Comet Collisions Inscribed in Saturn & Jupiter's Rings

What's the News: Looking at images of odd undulations in the rings of Saturn and Jupiter, astronomers have discovered that comets are to blame. The finding means that a planet's rings act as a historical record of passing comets, possibly leading to a better understanding of comet populations. "We now know that collisions into the rings are very common---a few times per decade for Jupiter and a few times per century for Saturn,"