A Few More Saturn Facts
Saturn's rings are the most expansive ring system of any planet we have seen. They are made up of countless particles, most of them extremely small, ranging in size from micrometers to meters. The system of Saturn's rings is divided into five components, but those divisions are actually subdivided into thousands of smaller ringlets. Saturn's F and G rings are thin and hard to see, while the A, B and C rings are broader and more easily viewed. The gap between the A and B rings is referred to as the Cassini division.
Photographs from NASA's Voyager missions have shown that Saturn's rings are made up of hundreds of thousands of what they call “ringlets”, or smaller rings. And the large gap between the A and B rings includes fainter rings that are more difficult to see without high-powered telescopes. The astronomers studying these facts about Saturn have ascertained that these rings can't be solid, but they could represent either material that never condensed into moons due to tidal forces, or satellites that were torn apart by tidal forces. The rings are made of ice particles, whose sizes may be as large as meters. The mass within the rings is about the size of a moon of medium mass, and the rings, upon closer view, are only about 10 km thick.
Scientists expected that ring particles colliding would make the rings more uniform in shape, but Voyager I discovered that there are changing structures within the radial direction. These are called “spokes”. Astronomers now believe that the gravitational forces by themselves can't account for the structure of the spokes, and instead they believe that electrostatic repulsion between the particles in the ring may play a role in the spokes' appearance and structure.
Voyagers I and II discovered that another of the facts about Saturn was her rings are not even all circular. Some even show up as though they are braided. The Voyagers also discovered that Saturn's outer ring is kept in its place by two small shepherd moons' gravitational interaction. These shepherd moons lie inside and outside of the ring. Although they were captured by the cameras on Voyager I and II, astronomers are still not entirely sure of how the rings' shapes are maintained. But these exploration vessels have greatly increased our knowledge of Saturn's rings. The photographs have also shown scientists just how much we still do not know about the origins, dynamics or structure of the rings.