Changes

|origname=mythic ferryman of the River [[Styx]]

|origname=mythic ferryman of the River [[Styx]]

|primary=Pluto

|primary=Pluto

|periapsis=19,640 km

|periapsis=19,640 km

|apoapsis=19,640 km

|apoapsis=19,640 km

|surfacearea=4,580,000 km² (0.898% earth)

|surfacearea=4,580,000 km² (0.898% earth)

|meantemp=53 K

|meantemp=53 K

}}'''Charon''' is the largest [[moon]] of the [[dwarf planet]] [[Pluto]]. It is so large, in fact, that some authorities hold that Pluto and Charon constitute a binary system because Pluto is not much more massive than is Charon.

}}

 

 

'''Charon''' is the largest [[moon]] of the [[dwarf planet]] [[Pluto]]. It is so large, in fact, that some authorities hold that Pluto and Charon constitute a binary system because Pluto is not much more massive than is Charon.

James W. Christy of the United States Naval Observatory is credited with its discovery on July 2, 1978. [[National Aeronautics and Space Administration|NASA]] hopes to obtain more extensive images of Charon and other bodies in the Pluto system with its first extensive deep-space mission to the Pluto system, ''New Horizons''.

James W. Christy of the United States Naval Observatory is credited with its discovery on July 2, 1978. [[National Aeronautics and Space Administration|NASA]] hopes to obtain more extensive images of Charon and other bodies in the Pluto system with its first extensive deep-space mission to the Pluto system, ''New Horizons''.

== 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.

==Young ice on Charon==

==Young ice on Charon==

There seems to be conclusive evidence for young ice on Charon.  Jason Cook of Arizona State University and his team of scientists have studied an icy coating on Charon, one of three moons orbiting Pluto.  These researchers have found that the ice has crystalline structures, indicating that it has not been there for millions of years.  Cosmic radiation from the Sun would break down the crystalline structures, so the ice must be younger that 100,000 years old.<ref><http://www.gemini.edu/icemachine></ref>  

There seems to be conclusive evidence for young ice on Charon.  Jason Cook of Arizona State University and his team of scientists have studied an icy coating on Charon, one of three moons orbiting Pluto.  These researchers have found that the ice has crystalline structures, indicating that it has not been there for millions of years.  Cosmic radiation from the Sun would break down the crystalline structures, so the ice must be younger than 100,000 years old.<ref><http://www.gemini.edu/icemachine></ref>  

There are two possible explanations for this observation.  Either the ice was there at the time Charon was formed and the moon is less than 100,000 years old or the ice was formed by a more recent process and gives no indication of its age.

There are two possible explanations for this observation.  Either the ice was there at the time Charon was formed and the moon is less than 100,000 years old, or the ice was formed by a more recent process and gives no indication of its age.

In order to fit the most widely believed evolutionary cosmologies, these researchers must justify the existence of young ice by theorizing a recent process.  They propose that there is cryovolcanism over practically all the three million square mile surface of Charon.

In order to fit the most widely believed evolutionary cosmologies, these researchers must justify the existence of young ice by theorizing a recent process.  They propose that there is cryovolcanism over practically all the three million square mile surface of Charon.

Two other moons in the Solar System ([[Enceladus]] and [[Europa]]) have evidence of cryovolcanism along fault lines caused by “tidal squeezing” from Saturn and Jupiter respectively. Charon is not subjected to tidal forces from Pluto and the theorized cryovolcanism covers a greater area than this process would explain. Additionally, there are no observed geysers on Charon producing global ice.

Two other moons in the Solar System ([[Enceladus]] and [[Europa (moon)|Europa]]) have evidence of cryovolcanism along fault lines caused by “tidal squeezing” from Saturn and Jupiter respectively. Charon is not subjected to tidal forces from Pluto and the theorized cryovolcanism covers a greater area than this process would explain. Additionally, there are no observed geysers on Charon producing global ice.

Cook and his team avoid this objection by supposing that there is radioactive material causing heating of subsurface water and ammonia, producing many small ice geysers that are too small to be seen from Earth.

Cook and his team avoid this objection by supposing that there is radioactive material causing heating of subsurface water and ammonia, producing many small ice geysers that are too small to be seen from Earth.