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Image of planet Pluto and Charon. - Pluto Basic Information
Image of planet Pluto and Charon. - Pluro Basic Information
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Pluto - 9th Planet

From Nick Greene,
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Planet Pluto Data:
  • MEAN RADIUS: 1150 km
  • MASS: 0.0025 (Earth=1)
  • DENSITY: 2.03 (g/cm^3)
  • GRAVITY: ? (Earth=1)
  • ORBIT PERIOD: 247.7 (Earth years)
  • ROTATION PERIOD: 6.39 (Earth days)
  • SEMIMAJOR AXIS OF ORBIT: 39.44 au
  • ECCENTRICITY OF ORBIT: 0.248
Pluto Description: Pluto was the Roman equivalent of the Greek god, Hades, ruler of the underworld. After many other suggestions and much debate, the dwarf planet was named Pluto partly due to its distance from the sun, which keeps it perpetually in the dark, and partly because "PL" are the initials of Percival Lowell, the man who theorized the existence of another planet and whose laboratory its discoverer, Clyde W. Tombaugh worked. Pluto was detected in 1930.

Formerly the ninth planet from the sun (usually), Pluto's composition is unknown. Its density indicates that it is probably a mixture of 70% rock and 30% water ice much like Triton. We also know very little about the atmosphere of Pluto, but it probably consists primarily of nitrogen with some carbon monoxide and methane. Pluto revolves about the Sun once in 247.7 Earth years at an average distance of 5.91 billion km (3.67 billion mi). Its orbit is so eccentric that it brings the planet Pluto inside the orbital path of the planet Neptune. Its rotation is reverse that of other planets. Pluto is about 2,360 km (1,475 mi) in diameter. The planet Pluto is the smallest planet in the solar system.

Pluto has one satellite, Charon, which is about 1200km (750ml) in diameter, making the pair the closest in size of any planet/moon combination.

On August 24, 2006, the International Astronomical Union (IAU) formally downgraded Pluto from an official planet to a dwarf planet.

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