One of the great cloud features, dubbed the Great Dark Spot by Voyager scientists, can be seen toward the center of the image. It is at a latitude of 22 degrees south and circuits Neptune every 18.3 hours. The bright clouds to the south and east of the Great Dark Spot constantly change their appearances in periods as short as four hours. 

 The Neptune View

 This cut-away view shows Neptune composed of an outer envelope of molecular hydrogen, helium and methane roughly the mass of one to two Earths. Below this region Neptune appears to be composed of a mantle rich in water, methane, ammonia, and other elements. These elements are under high temperatures and pressures deep within the planet. The mantle is equivalent to 10 to 15 earth masses. Neptune's core is composed of rock and ice, and is likely no more than one Earth mass.

Triton and Neptune

This mosaic combines an almost true-color picture of Neptune taken by the Hubble Space Telescope's (HST) Wide Field Planetary Camera (WFPC), with a picture of Triton taken with the HST's Faint Object Camera. Although faint, the image of Triton vaguely shows a brighter equatorial region. The south pole is to the lower left.

The picture of Neptune shows a bright cloud feature at the south pole, near the bottom of the image. Bright cloud bands can be seen at 30S and 60S latitude. The northern hemisphere also includes a bright cloud band centered near 30° N latitude. 

Cirrus-like Clouds

This image shows bands of sunlit cirrus-like clouds in Neptune's northern hemisphere. These clouds cast shadows on the blue cloud deck 35 miles below. The white streaky clouds are from 48 to 160 kilometers (30 to 100 miles) wide and extend for thousands of miles. 

Great Dark Spot

Feathery white clouds fill the boundary between the dark and light blue regions on the Great Dark Spot. The pinwheel shape of both the dark boundary and the white cirrus suggests that the storm system rotates counterclockwise. Periodic small scale patterns in the white cloud, possibly waves, are short lived and do not persist from one Neptunian rotation to the next.

 Twisted Rings

This portion of one of Neptune's rings appears to be twisted. Scientists believe it looks this way because the original material in the rings was in clumps that formed streaks as the material orbited Neptune. The motion of the spacecraft added to the twisted appearance by causing a slight smearing in the image. 

Cosmos...