A Dwarf Planet By Any Other Name…

Pluto... the planet that isn't a planet. Pluto was named after the Roman God of War (why take away the planetary status of a war god I don't know)

The International Astronomical Union (IAU), a Muggle astronomy organization, redid their classification system of planets. In 2006, they adopted a new definition of what constitutes a planet, and it included the following three stipulations:

a.  The celestial entity must be in orbit around the Sun.

b.  It has sufficient “self-gravity,” or gravitational pull on itself that it assumes a spherical shape.

c.  It has cleared the neighborhood of its orbit of any other space debris.

Pluto doesn't meet the last criteria, so when IAU confirmed the new definition, it lost it's planetary status. Pluto is now considered a dwarf-planet and not an official planet in our solar system.

Although mathematicians and astronomers predicted the existence of a “Planet X” going back to the nineteenth and early twentieth centuries, Pluto was not discovered until 1930. A 23-year old Kansan Muggle by the name of Clyde Tombaugh discovered the planet now known as Pluto in the Lowell Observatory in Flagstaff, Arizona in the United States of America. Although thousands of name suggestions flooded in from around the world, Pluto’s name was eventually chosen by an 11-year old girl named Venetia Burney from England.

Although there is still disagreement about Pluto’s exact composition, it is probably similar to that of Neptune’s moon Triton: approximately 70% rocky material and 30% ice. The dwarf planet’s surface pressure is very low, and it has a very tenuous atmosphere consisting of nitrogen with some methane and carbon monoxide. It is a tiny celestial body, possessing only about one-sixth the mass of our Moon.

Pluto’s orbit is rather erratic, and at times, it will cross orbits with Neptune, and pass closer to the Sun than the ice giant. The surface temperature tends to hover down between 38 and 36 Kelvins.

Despite Pluto’s small size, researchers have discovered five satellites orbiting the dwarf planet. The most well known object is a moon called Charon, named after the ferryman who guided souls across the River Archeron into the Underworld in Roman mythology. This moon was discovered in 1978. The four other satellites – Nix, Hydra, Kerberos, and Styx – were discovered to be orbiting Pluto in the twenty-first century. Charon’s orbital path around Pluto is interesting, as each celestial body always presents the same face to one another. This is referred to as being “tidally locked,” and some researchers have suggested that the two entities be titled a double dwarf planet.

To date, no Terrestrial spacecrafts have visited Pluto. However, the NASA space probe New Horizons is intended to reach the dwarf planet in the year 2015. The probe will take photos and make observations of Pluto and its satellites before continuing on to the Kuiper Belt, a region of the solar system much like our Asteroid Belt with debris from the early formation of the solar system.