Planetary rings, like those of Saturn, are made up of countless particles ranging in size from micron-sized dust up to miniature moons tens of meters across. These particles collide frequently, but at very low speeds, depending on the local ring environment. These collisions sculpt the ring systems. In some cases particles stick together to form moonless and clumps. Understanding what happens when ring particles collide will help us understand big questions about the origin and history of the ring system as well as some of the fascinating discoveries made at Saturn by the Cassini Mission, for example.
This image from the Cassini mission at Saturn is a composite made from several individual pictures taken while the Sun was on the opposite side of Saturn as seen by Cassini. The rings are illuminated by sunlight shining through them and reflected onto them by Saturn’s atmosphere. In this geometry, faint outer rings made of dust-sized ice grains are highlighted. Credit: NASA/JPL/SSI.