Neptune
| Diameter: | 49.500 km |
| Mass: | 86.81 x 10 24 |
| Density: | 1.8 g/cm3 |
| Max distance from sun: | 4.54 billion kilometers |
| Min distance from sun: | 4.46 billion kilometers |
| Length of day: | 17 hr. 6 min |
| Length of Year: | 165 Earth years |
| Temperature: | -210° C |
| Surface Gravity: | 11.77 m/s2 (1.2 of Earth's). |
| Axial title: | 29° 36' |
| Satellites: | 8 - Triton , Despina, Galatea, Halimede .... |
Neptune has a methane atmosphere that reflects blue very well giving it a characteristic bright blue colour. Occasionally white clouds appear on the surface of the planet but otherwise it looks very tranquil. The truth, however, is that the surface is in a very agitated state having winds in excess of 2000 kph. A large dark area was discovered and named the Great Dark Spot, which rotated once every sixteen days.
Neptune was only discovered in 1846 as a result of its gravitational effect on neighbouring Uranus.
Neptune has a mantle made up of ice that surrounds an iron core. The atmosphere is mainly hydrogen, helium and methane.
Neptune as some faint rings made up of mainly icy dust.