Hobbies And Interests
Naming Pluto
Pluto's name came about as a result of a public competition. The winner was an 11-year-old British girl named Venetia Burney. The name Pluto was acceptable because of its allusion to the god of the cold, dark and mysterious underworld.
Relative Size
Pluto was an extremely small planet. The final calculation of its size revealed that it was smaller than the planetary moons Io, Europa, Titan and Ganymede. In fact, Pluto is even smaller than the Earth's moon.
Moons
Despite its diminutive size, Pluto has three moons. One of those moons, Charon, has a diameter that's almost as large as Pluto's. It is just over 12,000 miles away from the planet, which has led some to claim that Pluto and Charon form a double planetary system. Pluto's other two moons are Nix and Hydra.
Orbiting Inside Neptune
The orbit of Pluto takes it inside the orbit of Neptune, which meant that they occasionally switched places as the planet farthest out in the solar system. From 1979 to 1999, Pluto was closer to the sun than Neptune.
Lenth of Orbit and Rotation
Pluto's orbit around the sun takes 248 years. The planet's rotation on its axis is also much slower than Earth's. The length of a day on Pluto is equivalent to almost seven days on Earth.
Estimated Surface Composition
The surface of Pluto is believed to be composed of frozen methane, nitrogen and carbon monoxide. As Pluto draws nearer to the sun, these ices begin to thaw, giving the dwarf planet a temporary, thin atmosphere.
Area
The circumference of Pluto measures roughly 4,494 miles. Its surface area is approximately 6,430,000 square miles.
Eccentric Orbit
Pluto's orbit is described as being eccentric, which is a technical description for an elliptical orbit. Pluto's eccentric orbit is inclined to the plane in which the other planets in the solar system orbit. This means that Pluto orbits the sun in a manner similar to how a comet orbits the sun.
Difficulty Seeing Pluto
Most amateur astronomers have never actually seen Pluto. The dwarf planet is much fainter than the two planets closest to it, Uranus and Neptune. The ability to see Pluto from Earth requires instruments capable of detecting its 14th magnitude glow.
Demotion
The International Astronomical Union was responsible for downgrading Pluto from a planet to a dwarf planet. The criteria for meeting the definition of a planet included the fact that it orbits the sun, it has enough gravity to pull itself into a spherical shape and it has to have cleared the neighborhood of its orbit by either consuming competing objects or by forcing them away with gravity. Pluto met the first two criteria, but failed on the third and was demoted.