Pluto A Dwarf Planet

General Facts About Pluto Pluto orbits beyond the orbit of Neptune (usually) It is much smaller than any of the official planets and now classified as a "dwarf planet“ In Roman mythology, Pluto (Greek: Hades) is the god of the underworld Pluto was discovered in 1930 by a fortunate accident we now know that there are a very large number of small objects in the Kuiper Belt beyond the orbit of Neptune, some roughly the same size as Pluto

More General Facts About Pluto Pluto has a satellite, Charon. Charon was discovered in 1978 In late 2005, two additional tiny moons were found to orbit Pluto (known as Nix and Hydra). They are estimated to be between 60 and 200 km in diameter Pluto's orbit is highly eccentric. At times it is closer to the Sun than Neptune (as it was from January 1979 thru February 11 1999) Pluto rotates in the opposite direction from most of the other planets Pluto's equator is at almost right angles to the plane of its orbit

Comparison of Earth and Pluto orbit: 149,597,871 km (1 AU) from the Sun (average) diameter: 12,713 km mass: 5.9736 x 1024 kg Revolution: 365.25 days Rotation: 24 hours Rotational axis: tipped 23.5 degrees orbit: 5,913,520,000 km (39.5 AU) from the Sun (average) diameter: 2274 km mass: 0.0125 x 1024 kg Revolution: 247.7 Earth years Rotation: 6.387 days Rotational axis: tipped 122 degrees

Comparison of Earth and Pluto Pluto is smaller than seven of the solar system's moons (the Moon, Io, Europa, Ganymede, Calistoga, Titan and Triton)

Missions to Pluto Pluto has not yet been visited by a spacecraft Even the Hubble Space Telescope can resolve only the largest features on its surface A spacecraft called New Horizons was launched in January 2006. If all goes well it should reach Pluto in 2015

New Horizons Mission Since Pluto is so far from Earth, little was known about the dwarf planet's size or surface conditions until 2015, when NASA's New Horizons space probe made a close flyby of Pluto.

New Horizons Mission What did New Horizons find? Pluto has a diameter of 1,473 miles (2,370 km) A variety of surface features, including mountains that reach as high as 11,000 feet (3,500 meters), comparable to the Rocky Mountains on Earth. Pluto's surface is also covered in an abundance of methane ice (New Horizons scientists observed significant differences in the way the ice reflects light across the dwarf planet's surface.) a large heart-shaped region known unofficially as Tombaugh Reggio (after Clyde Tombaugh)

New Horizon Photos of Pluto

Why Is It No Longer Considered a Planet? Due to additional objects being discovered including Eris (a dwarf planet in the Kuiper Belt) which is 27% more massive than Pluto, the IAU (International Astronomical Union) reclassified Pluto and the other objects as dwarf planets Kuiper Belt objects are comet-like in composition