NEPTUNE - FEATURES OF NEPTUNE

THE GREAT DARK SPOT:
       Neptune has one storm system know as the Great Dark Spot. The storm system is thought
to be rotating counter clockwise due to a spiral shape of both the dark boundary and the 
white cirrus surrounding the spot. Recent observations made with the Hubble Space Telescope 
indicate that the Great Dark Spot actually no longer exists. But, a second " great dark 
spot" has been observed in the northern hemisphere of Neptune. Because Neptune radiates 
twice as much energy as it receives from the dim and distant sun, the mechanism that drives 
its weather systems must be very different from that of Earth. An internal heat source may 
exist that warms the cloud tops from below. Slight changes in the temperature differential 
from cloud bottom to top might trigger rapid, large-scale changes in atmospheric 
circulation.

RINGS:
       Neptune has a set of four rings which are very narrow and faint. They are made up of 
dust particles made by tiny meteorites that have crashed into Neptune's moons. The rings 
appear to be arcs from ground based observations but the Voyager 2 revealed that the arcs 
turned were bright spots or clumps in the ring system. The exact cause of these bright 
clumps is unknown.
       The ring system was found to contain several faint rings, the outermost of which, 
Adams, contains three prominent arcs now named Liberty, Equality and Fraternity. Several 
other rings were detected as well. In addition to the Adams Ring which is 63,000 km from 
the center of Neptune, the Leverrier Ring is at 53,000 km and the broader, fainter Galle 
Ring is at 42,000 km. A faint outward extension to the Leverrier Ring has been named 
Lassell and is bounded at its outer edge by the Arago Ring at 57,000 km.