At one time, Saturn, with it's beautiful ring system, was thought to be an anomaly in the Solar System: why did Saturn, and no other planet, have rings? As we have explored the outer planets in more detail, we now know that there are multiple ring systems in the Solar System. None are as spectacular as that of Saturn, but we now view rings as common occurences.
The adjacent image
Jupiter also has a ring, though it is extremely
faint. The ring was discovered by Voyager I in 1979 and is at a radius of
about 1.8 times the radius of the planet (which is inside the radius of the
innermost moon). It seems to be composed of small (micron size) particles,
probably from Io's volcanoes and from debris knocked off the inner moons by