Pluto is a small, cold, rocky, dwarf planet. Pluto was considered to be a planet from its discovery until 2006, when it was reclassified as a dwarf planet. Pluto is the smallest "planet" in our Solar System; it has a very eccentric orbit.
Pluto is usually the ninth and farthest "planet" from the Sun. Sometimes, Pluto crosses orbits with Neptune and for a while, Neptune is the planet farthest from the Sun.
Pluto was the last "planet" to be discovered. It was found by Clyde W. Tombaugh in 1930. Very little is known about Pluto.
Pluto is orbited by one large moon (named Charon) and two tiny moons (named Nix and Hydra). Charon was discovered by Jim Christy in 1978.