| Average Distance From Sun: | 5900 Million KM |
| Diameter: | 3000 KM |
| Mass: | 0.0025 Earth Standard |
| Gravity: | 0.2 Earth Standard |
| Atmosphere: | Methane |
| Moons: | One, Charon |
| Pluto Year: | 248 Earth Years |
| Pluto Day: | 6.5 Earth Days |
Pluto is the smallest and, usually, outermost planet of the solar system.
The existence of Pluto was predicted by calculation by Percival Lowell and the planet was located by Clyde Tombaugh 1930.
Pluto's highly elliptical orbit occasionally takes it within the orbit of Neptune, such as 1979-99. It is of low density, composed of rock and ice, with frozen methane on its surface and a thin atmosphere. Charon, Pluto's moon, was discovered 1978. It is about 1,000 km in
diameter and orbits the planet at a height of about 20,000 km every 6.39 days - the same time that Pluto takes to spin on its axis. Some astronomers have suggested that Pluto was a former moon of Neptune that escaped. Charon remains permanently above the same place on Pluto.
There is currently some debate over whether Pluto can be classed at a actual planet, due to its tiny size, the most likely case is that Pluto & its companion Charon, are merely large fragments of rock that are being held in orbit.
Charles Hess EMailed me to say that it has been decided that Pluto will remain classified as a planet, and that Pluto is currently inside the orbit of Neptune, and will remain so for a few years, making Neptune the current furthest star from the Sun.