Question #120807. Asked by unclerick.
Last updated Sep 15 2016.
Originally posted Mar 22 2011 7:04 PM.
Uranus' outermost and most massive ring, called the Epsilon Ring, is only about 100 kilometers wide and probably less than 100 meters thick. The other ten dark and narrow rings have a combined mass less than the Epsilon Ring. The six rings of Neptune are less significant than Uranus' and the ring particles are not uniformily distributed in the rings. Like Saturn's F ring, the rings of Uranus and Neptune are kept narrow by shepherd satellites. The narrowness and even clumpiness of the rings means that the rings can last for only a short time---a million years or so, unless the rings are replenished by material ejected off the moons in large collisions.