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== Orbital and rotational characteristics ==

== Orbital and rotational characteristics ==

[[Image:Pluto3.gif|left|thumb|Pluto(center) with moon [[Charon]]. NASA image]]Charon is locked into a resonating orbit with its primary, Pluto. Its axis is not tilted, and its sidereal month and day are the same length; therefore, like the [[Moon]] of [[Earth]], Charon always presents the same face toward Pluto. Insofar as observations to date have determined, Charon's orbit is perfectly circular and in the same plane as is Pluto's equator.

[[Image:Pluto3.gif|left|thumb|Pluto(center) with moon Charon. NASA image]]Charon is locked into a resonating orbit with its primary, Pluto. Its axis is not tilted, and its sidereal month and day are the same length; therefore, like the [[Moon]] of [[Earth]], Charon always presents the same face toward Pluto. Insofar as observations to date have determined, Charon's orbit is perfectly circular and in the same plane as is Pluto's equator.

Note, however, that while Charon's revolution and rotation are technically prograde with respect to Pluto's own rotation, they are ''retrograde'' with respect to the [[Sun]]. This is because Pluto's own rotation is retrograde with respect to its own orbit.

Note, however, that while Charon's revolution and rotation are technically prograde with respect to Pluto's own rotation, they are ''retrograde'' with respect to the [[Sun]]. This is because Pluto's own rotation is retrograde with respect to its own orbit.