The current Hubble Space Telescope photos of Pluto show that it has retreated to its aphelion (winter) orbit, far away from the sun. It has an episodic atmosphere (gasses which surround a star) which is a phenomenon of orbiting inside the orbit of Neptune for 20 years where it is closer to the sun than Neptune. Then it cruises far away from the perihelion (summer) orbit to freeze and remain that way until the 22nd century.
So, presently the Dwarf Planet Pluto is far-out, away from the earth and sun. Since it has never been visited by a spacecraft it's origin is unknown. The planets are divided as either terrestrial (like Earth), or gas (like Saturn). It is considered to have a weak gravity, and an extreme elliptical orbit because it rotates on its head. The axial tilt is 10 degrees higher than most planets.
Pluto was named after the Roman god of the underworld.
Pluto, the grisly god,
who never spares,
Who feels no mercy, and
who hears no prayers. The Iliad (Book IX), Homer
The same god in Greek mythology is named Hades.
It has three moons, although two of them were only discovered in 2005. They are named, Nix, and Hydra. Charon is the largest of the three, almost as large as Pluto. They work as a double planet (binary planet) - similar to the earth and sun when occultation occurs. When one astronomical object passes in front of another. Charon was named after the boatman who ferried dead souls across the river Styx to Hades, and after Charlene, wife of J.W. Christy who discovered Charon.
Many scientists originally felt that Pluto was too small to be considered a planet and in 2006 it was indeed "demoted" to a dwarf planet. Also, since it is gravitationally bound with Charon it wasn't that unusual from many asteroids known to be gravitationally bound. The Planet Pluto became the Dwarf Planet Pluto. The solar system was decreased from 9 to 8 planets:
- and Neptune.
Six years later a new spacecraft, New Horizons, was launched from Cape Canaveral Air Force Station, Fla. to check out the icy dwarf planet. It is the fastest spacecraft launched from earth, and got even more speed when it had a chance encounter with Jupiter. It rode Jupiter's gravity, which boosted it's speed and shaved 3 years off the trip to Pluto. That in itself is historic, and really far-out!
Hopefully New Horizons will fly by Pluto in 2015 and get loads of feedback of Pluto's atmosphere. It will enhance our knowledge of the earth's evolution too.