Pluto is much smaller than any of the officially plants and is now classified as a Dwarf Planet. Pluto was discovered in 1930 by accident. Calculations which later turned out to be in error had thought there was a planet beyond Neptune. Based on the motions of Uranus and Neptune Clyde W. Tombaugh from Lowell Observatory in Arizona did a careful sky survey and found Pluto anyway although he didn't know of the mistake he had made.

Pluto is no longer considered our solar system's ninth planet. But after the discovery of similar intriguing worlds deeper in the distant Kuiper Belt. This new class of worlds may offer some of the best evidence about the origins of our solar system. Pluto is also a member of a group of objects that orbit in a disc-like zone beyond the orbit of Neptune called the Kuiper Belt. This distant realm is populated with thousands of miniature icy worlds, which formed early in the history of our solar system. These icy, rocky bodies are called Kuiper Belt objects or transneptunian objects.

In August 1992, JPL scientist Robert Stathel telephoned Clyde Tombaugh requesting permission to visit his planet. He was given permission and ready to go but then in 2000 NASA cancelled the launch because of costs. A revised mission to Pluto was given funding from the US Government in 2003. The mission was launched on 19 January 2006. The closest the spaceship will be to the planet will be on July 14 2015.

external image pluto.jpg

Information about Pluto:

Orbit: 5,913,520,000 km from the sun on average.Diameter: 2320 km.Mass: 1.27e22 kg.Volume: 6 387 257 783km3


What is a planet?
A planet is defined by three properties:

• It is a celestial body that orbits the Sun.
• It is massive enough that its own gravity causes it to form in a spherical shape.
• It has cleared the neighbourhood around its orbit.
Under this definition our solar system has eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune.

Pluto is not a planet because it is in an area of space populated by numerous other objects. Pluto is now designated a dwarf planet, and it is the prototype of a class of objects located beyond the orbit of Neptune . Other dwarf planets are Ceres which is the largest asteroid found in the Asteroid Belt found between the orbits of Mars and Jupiter and 2003 UB 313 which is an icy body that is larger and further away than Pluto. The IAU will establish a process to determine what other bodies fit in this category.

Done by: Billy Dean and David Maritz