37. Neptune's Rings
Earth-based observations of occulted starlight showed what appeared to be incomplete thin rings, or ring arcs, orbiting Neptune. This Voyager 2 image shows two thin rings around Neptune; an overexposed crescent Neptune is visible within the bright oval (the result of special processing) at lower right. The outermost ring has three discrete segments where there is much more material than elsewhere in the ring; these localized areas of enhanced ring material are what were detected from Earth as the ring arcs. This image was taken after Voyager 2 had passed Neptune, so the light from the ring material is scattered in the forward direction, indicating that the material is very fine-grained (likely only micrometers in diameter, or about one millionth of an inch). The origin of the localized clumps is not known, but it may be related to isolated larger objects within the rings that are a source for the small ring materials.
Voyager 2 image (Press Release P-34712).