Rings of Rhea dips bear some similarity to the method by which the rings of Uranus were discovered in 1977. The slight deviations from absolute symmetry may be due to "a modest tilt to the local magnetic field" or "common plasma flow deviations" rather than to asymmetry of the rings themselves, which may be circular. Not all scientists are convinced that the observed signatures are caused by a ring system. No rings have been seen in images, which puts a very low limit on dust-sized particles. Furthermore, a ring of boulders would be expected to generate dust that would likely have been seen
Space exploration winds of any planet in the Solar System, measured as high as 2,100 km/h. "Voyager 2" also examined Neptune's ring and moon system. It discovered 900 complete rings and additional partial ring "arcs" around Neptune. In addition to examining Neptune's three previously known moons, "Voyager 2" also discovered five previously unknown moons, one of which, Proteus, proved to be the last largest moon in the system. Data from "Voyager 2" supported the view that Neptune's largest moon, Triton, is a captured Kuiper belt object. The dwarf planet Pluto presents significant challenges for spacecraft because of its great distance from Earth