endent orbit. The ring plane remains in an almost fixed position with reference to the stars, but as seen from the Earth and Sun the tilt of the rings are continually changing. Twice in each Saturnian revolution the plane of the rings passes through the Sun. A few months before and after each such occasion, the ring plane passes through the Earth, which is near the sun as viewed from Saturn. Two of the three main rings, termed A (outer) and B, are bright. In 1675 G.D. Cassini, at the Paris Observatory, discovered the gap between them, known as Cassini’s Division. The “ring” seen by Huygens was a combination of the two, and his telescope was not good enough to show the division. Ring B is much brighter of the two. In 1837 J.F. Encke, at Berlin, discovered a less prominent division in Ring A, known as Encke’s Division. In 1850 a dusky inner ring, ring C, was discovered by W.C. Bond and G.P. Bond. This is known as the Crpe Ring.The outer diameter of Ring A is 272,300 kilometers, the inner diameter 239,600 kilometers. For ring B, the outer and inner diameters are 234,200 kilometers and 181.1000 kilometers. The inner diameter of ring C is 149,300 kilometers, so that it extends 17,000 kilometers above the cloud tops.New rings have been discovered since then. A dusky ring, closer in than ring C was reported by telescopic observers. Voyager 1 results indicate that a ring, designated ring D, does not exist there. Outside ring A is the clumpy and braided Ring F. Rings E and G were also shown on Voyager 1 images.Voyager 1 showed that the rings are much more complex than had been thought. Each contains hundreds of components, and there are several distinct narrow rings inside the Cassini Division. It was once thought that the main divisions in the ring system were due to the cumulative perturbation effects of Saturn’s satellites, but this explanation is clearly inadequate, and other forces must be involved.Saturn has 1...
