Pluto

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Pluto
Venus Mercury Mars Minor Planets.		Jupiter Saturn Uranus Neptune

DATA

Distance from the SUN	Mean: 5900 million Km (39.5 au.) Max: 7375 million Km (49.28 au.) Min: 4425 Km (29.65 au.)
Sidereal period	247.7 years (90465 days)
Syodic period	366.7 days
Rotation period	6d 9h 17s
Mean orbital velocity	4.7 Km/sec
Axial inclination	22deg .46.
Orbital inclnation	17deg .15
Diameter	2324
Reciprocal Mass (Sun = 1)	135500000
Density (water =1)	2.0
Mass (Earth = 1)	0.0022
Escape Velocity	1.18 km/sec
Surface gravity (Earth = 1)	0.06
Mean surface temperature	-230 °C

Opposition Dates

Date	Declination at opposition Deg.
4 June 2001	-12
7 June 2002	-13
9 June 2003	-13
11 June 2004	-14
14 June 2005	-15

Description.

Pluto was discovered in 1930 at the Lowell Observatory by Clyde Tombaugh following the search for the planet thought to be disturbing Neptune. It turns out Pluto is not big enough to disturb Neptune's orbit in the slightest bit. Pluto is the smallest Planet and the farthest away from the Sun as wall as having the lowest density. In fact it is so unlike the outer planets it's classification as a planet has been questioned. It has a thin atmosphere that freezes solid when it moves away from the Sun. It rotates backward and only one revolution every six days. It's orbit is so eccentric it crosses inside Neptune's orbit for about 20 years, then it passes back into it's own orbit and once again becomes the ninth planet. The last time was 1979 to 1999, so as it's year is 248.54 Earth years we have a little while to wait for it to happen again. Because Pluto is so distant we know little about it. Pluto can only be observed in a moderately sized telescope and even then it only appears as a tiny point of light only reaching about mag. 14.

Satellites.

Pluto has one satellite called Charon. Both Pluto and Charon rotate so that each show the same face to each other all the time. So this means that Charon's revolution about Pluto is the same as Pluto's rotational period (6.3872 Earth days). Charon's average distance from Pluto is only 19640 km (about 17 of Pluto's radii. Pluto and Charon are more like a double planet system than a planet and it's satellite.