- The physical makeup of Neptune is very gaseous, it consists mainly of hydrogen and helium but about 2.5-3% of the planet is methane.
- The Voyager2 spacecraft reached Neptune in 1989 and observed a dark storm system with a bright core of feathery clouds. Wind speeds on Neptune reach 325 meters per a sec (700 mph), moving in a retrograde direction that is opposite to the direction of its rotation. These are the strongest retrograde winds seen on any planet in the solar system.
- Neptune's distance from the sun is 4,497,000,000 km (2,749,000,000 mi)
- The length of a day on Neptune is 18 hours and 24 minutes.
- The length of a year on Neptune is 164.8 Earth years.
- Neptune has 8 satellites that revolve around the planet, 6 of them were discovered by Voyager 2 giving Neptune a total of 8 moons. Neptune also has five rings that surround it there are 2 bright narrow rings and three fainter ones that are fuzzier sheets of orbiting materials. Another interesting fact is that, in a large telescope the planet appears as a small blue disk. The best pictures of Neptune from earth show discrete bright clouds and a bright haze over the South Pole of the planet.
- The temperature on Neptune is predicted to be about -228?c or -378?f.
- The Planet was discovered during 1845 and 1846 by an Englishman John Couch Adams and the Frenchman Urbain Jean Joseph Leverrier when unknown to each other, they independently calculated where an eighth planet would have to be in order to explain slight perturbations in the orbit of Uranus.
- Voyager 2 made a flyby of Neptune on August 25, 1989 (with its closet approach of 4,827-km/3,000-mi) and the spacecraft provided new information such as the existence of a total of eight satellites. It also observed a dark storm system with a bright core of feathery clouds.
- The planet is named after "Neptune" for a Roman Sea god because of its blue color and strong winds.