EDITOR'S PICK: See the International Space Station in real-time (on any computer) at:  http://liftoff.msfc.nasa.gov/ temp/StationLoc.html

Pluto is the ninth planet from the Sun and outermost known planet of the solar system. Pluto revolves about the Sun once in 247.7 Earth years at an average distance of 5.91 billion km. The planet's orbit is so eccentric that at certain points along its path Pluto is slightly closer to the Sun than is Neptune. Pluto is about 2,360 km in diameter, about two-thirds the size of Earth's moon. Discovered in 1930, Pluto is the most recent planet in the solar system to be detected.