Don't get plutoed...

What? You've never heard the term? This neologism began to show up in pop culture following the International Astronomical Union's (IAU) reclassification in 2006 of Pluto from the 9^th planet in our solar system to merely a dwarf planet. The American Dialect Society chose “plutoed” as the 2006 Word of the Year in honor of this change and defines it as “to demote or devalue someone or something.”

This little planet (yes, pun intended) has had a long and eventful journey through our history. Astronomers began looking for Pluto in the late 19^th century, although at the time they were unsure what exactly they were looking for, simply searching for Planet X. The theory was that minor irregularities in Neptune's orbit were caused by the gravitational pull of another, as yet undiscovered, planet.

Finally, on February 18, 1930, American astronomer Clyde Tombaugh confirmed the existence of Pluto through a series of photographs taken earlier that year at the Lowell Observatory in Flagstaff, AZ. The observatory's part in the discovery was appropriate since its founder, Percival Lowell, was the astronomer whose calculations spurred the search for Planet X in the first place.

Because the discovery was made there, the Lowell Observatory had the right to name the planet and received over 1,000 suggestions before narrowing it down to just three: Minerva, Cronos, and Pluto. A unanimous decision resulted in the planet being named after the Roman god of the underworld, a name suggested by an 11-year-old school-girl in Oxford, England who said she considered the name appropriate for such a cold, dark world.

After 76 years with planetary status, Pluto was demoted to dwarf planet after the discovery of celestial bodies with similar characteristics in nearby space. Under the new classification system, only bodies large enough to have cleared the neighborhood of their orbit qualify as “planets.” Bodies that have not been rounded by their own gravity are “small solar system bodies.” Dwarf planets fall somewhere in between.

Artist’s impression of how the surface of Pluto might look, according to one of the two models that a team of astronomers has developed to account for the observed properties of Pluto’s atmosphere, as studied with CRIRES. The image shows patches of pure methane on the surface. At the distance of Pluto, the Sun appears about 1000 times fainter than on Earth.

Interesting facts about Pluto:

• Pluto is the second most massive dwarf planet in our solar system after Eris, a dwarf planet discovered in January 2005.
  
• Pluto is orbited by three moons: Charon, Nix and Hydra. Charon and Pluto form a binary system and are unusual because they always present the same face to each other meaning that from either body, the other is always in the same position in the sky.
  
• Because of its highly elliptical orbit, there are periods during its orbit when it is actually closer to the sun than Neptune, the 8^th planet in our solar system. However, the positioning of those orbits prevents the two planets from ever being in danger of collision.
  
• Pluto takes 248 Earth years to orbit the sun, 6.39 Earth days to rotate once on its axis, and experiences extreme seasons because of the 120 degree axial tilt.
  
• More information on Pluto is expected to come to light in 2015 when the robotic spacecraft, New Horizons, arrives to study the planet and its moons.