The flyby of Voyager 2 past Neptune in 1989 revealed very faint rings that are less pronounced than those of Saturn or even those of Jupiter and Uranus. Five rings total are confirmed to exist. These rings are composed of mostly dust particles of varying sizes. The particles in the outermost ring (called the Adams ring) clump together in five places, creating relatively bright, curved segments at different spots along that ring. That is unlike any other planetary ring in the solar system, and it is not known why this has happened; it probably has to do with the gravitational effects of Galatea, a moon of Neptune which shepherds the Adams ring.