Discovered in 1930, Pluto was classified as the ninth and most distant planet in our solar system until the discovery of Eris, in 2006. The latter planetoid, actually larger than Pluto and also possessing a moon (Pluto has three), triggered a major controversy in astro-nomical circles, leading to the reclassification of Pluto as just another large object in the Kuiper Belt; this Belt is a broad swath of asteroids that circle the sun beyond the orbit of Neptune.
Smaller than our moon, Pluto orbits the sun every 248 years; its elliptical orbit, with a radius ranging from 2 to 3.4 billion miles, actually takes Pluto closer to the sun than Neptune during part of its orbit. Furthermore, during its "closer" approach, Pluto develops a thin atmosphere as some of the frozen methane, nitrogen and carbon dioxide on its surface is vaporized.
Regardless of its scientific classification, Pluto will remain a distant, dark world of rock and ice. Humans, fueled by theoretical arguments and emotional sentiment, will likely continue the debate, hoping to reclaim this orphan as one of our own. But humans are like that.
