Pluto. This is Pluto, the farthest planet of the solar system, as seen by NASA's Hubble Space Telescope with the European Space Agency (ESA) Faint Object Camera, in 1994. Pluto is the last planet of the solar system, a faraway world, 3.6 billion miles (5.8 billion km) away from the Sun! It takes Pluto 248 years to complete one orbit. The other characteristics of Pluto are that its orbit's plane is highly tilted to the mean plane of the other planets by a large 17-degree, and that its orbit is highly eccentric, bringing the planet as far as inside the orbit of Neptune. Pluto was discovered in the year 1930 only, by Clyde W. Tombaugh, an enthusiastic amateur astronomer who had been hired as a member of the team which was continuing Percival Lowell's quest of the hypothetical "Planet X", a planet which was thought to lie in these dark parages of the solar system. The other object on the picture, at the upper right, is Pluto's only moon, Charon. Pluto is badly known as no space mission ever was sent there. We will have to wait 2015 that NASA's New Horizons mission, due to leave Earth in 2006, eventually glide along these desolated worlds, before continuing further still, taking the occasion to venture into the Kuiper Belt, this zone of small, icy leftovers of the solar system formation. picture site 'Amateur Astronomy' based on a picture Dr. R. Albrecht, ESA/ESO Space Telescope European Coordinating Facility; NASA