This picture of Neptune was taken on August 20, 1989 by Voyager 2. In the center of the image, the Great Dark Spot can be seen. The latitude of the planet Neptune is 22 degrees south and circuits every 18.3 hours. The east and the south of the Great Dark Spot change their appearances constantly in four hours.
The internal structure of Neptune can be inferred from the planet's radius, period of rotation, mass, and shape of its gravitational field and the behavior of hydrogen, helium, and water at high pressure. The picture shows a cut-away view of Neptune composed of an outer envelope of molecular hydrogen, helium and methane. Below this region Neptune is composed of a layer rich in water, methane, ammonia, and other elements with high temperatures and pressures. Ice and rock constitutes the core of Neptune.
This picture gives a nearly true 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. Even though, the image of Triton is faint but it clearly shows a bright equatorial region. In the lower left, the south pole is clearly visible. Near the bottom of the image a bright cloud feature can also be seen. It can be seen at 30S and 60S latitude. Another bright cloud can also be seen at 30N latitude in the northern hemisphere.
The dynamic nature of Neptune is clearly visible from the fact that the second smaller ...