Pluto was discovered in 1930, 94 years ago. Pluto was long considered our solar system's ninth planet. But after the discovery of similar intriguing worlds deeper in the Kuiper Belt, tiny Pluto was reclassified as a dwarf planet in 2006 by the International Astronomical Union.
Pluto's 248-year-long orbit has an eccentricity of 0.25, which means that Pluto's distance from the Sun is as little as 29.7 astronomical units (temporarily bringing it closer than Neptune) and as great as 49.3 astronomical units. For about 20 years in each orbit, Pluto is actually closer to the Sun than Neptune.
