Pluto
Planet statistics
Distance from the Sun (in millions)
	Maximum:  	4,583 miles 
			7,375 km
			49.19 AU
	Minimum:  	2,766 miles 
			4,425 km
			29.69 AU				
	Mean: 		3,666 miles 
			5,900 km
			39.44 AU
Period of revolution ("one year"): 247.7 years
Period of rotation (equatorial): 6 days 9 hr.
Mean orbital velocity per second: 2.9 miles (4.7 km)
Inclination of axis: 122.5°
Orbital eccentricity: 0.248
Orbital inclination: 17.15°
Diameter at equator: 	1,430 miles 
			2,300 km
			Earth????
Oblateness:  0
Escape velocity per second: 	0.7 miles
				1.1 km
Mean surface temperature: -382F / -230C / 43° K
Mass:	1.29 x 10^22 kg
	(Earth = 1): 0.002
Volume (Earth =1): <0.01
Density (water = 1): 2.03
Surface gravity (Earth = 1): 0.4 m/s^2
Maximum apparent diameter as seen from Earth (seconds of arc): 0".2
Mean diameter of Sun as seen from the planet: 49"
Albedo:  0.4
Number of known satellites:  1


Satellite statistics
Charon
Mean distance from center of planet:	11,800 mi. (19,000 km)
Orbital period:	6.39 days
Orbital eccentricity:	low
Orbital inclination to planet's equator:	low
Diameter:	745 mi. (1,199 km)
Escape velocity:	low
Magnitude:	19
Maximum apparent diameter as seen from  the planet:	—


Planet composition
Little is known about composition of Pluto, but its low density indicates a major constituent must be ice composed of water, ammonia, and methane. It is speculated that methane frost covers the surface.

Pluto's diameter is about 2,400 km (2/3 the size of our moon);  Charon's is approximately 800 km.
Together, Pluto and Charon have about 1/5 the mass of our Moon.

[Rick:  No composition stats available.]
Topography
No surface detail has been detected on either Pluto or its satellite, Charon.


Atmosphere
Pluto's tenuous atmosphere is known to contain methane, but researchers speculate that the major component is nitrogen. As the planet moves away from the Sun in its elliptical orbit, the atmosphere freezes and falls to the planet's surface. Even if  Pluto were massive enough to retain an atmosphere, it would be so cold that most gases (except neon) would be frozen out.  The mean surface temperature on Pluto is -382.27°F / 212° C / 485° K, with extremes ranging from -350° F /  -195° C / 78° K to -390°F  / -217° C  /  56° K. 


Magnetic fields and gravity
Pluto has no known magnetic field.  Its surface gravity estimated to be around 0.08.


Orbit and rotation
 It takes 248 years for Pluto to complete an orbit of the Sun. Its equatorial rotation is 6.3 days.

At 17°, Pluto has the most highly-inclined orbit of all planets. Pluto also has the most eccentric orbit. This eccentricity takes Pluto inside Neptune's orbit, where it has been since 1977 and will remain until March 1999.


Moons (and/or rings)
The only known satellite is Charon, which orbits Pluto every 6.3 days. Charon appears to be covered in water ice (as opposed to the methane ice that covers Pluto).  Charon's orbit is locked with Pluto's, so the same sides of the globes always face each other.

Mythology
Pluto was named for the Greek god of the lower world.


Discovery and exploration
Clyde Tombaugh discovered Pluto in January 1930 based on calculations and predictions made by Percival Lowell at the turn of the century.  James Christy first speculated about the existence of Pluto's satellite, Charon, in 1978. The Hubble Space Telescope later verified its existence. Pluto is the only major body in our solar system that has not been visited by an exploratory probe, but NASA is currently exploring the possibility of such a probe.

[Rick:  No data found on early belief in life forms.]