Ganymede

I have decided to do a few posts on some of the major moons of the solar system.  I am not sure how often I will post these, but here is the first one.

Ganymede

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Here a some facts about Ganymede:

• Ganymede is the largest moon in the solar system with a diameter of 3273 miles (5268 km).  In fact, Ganymede is slightly larger than the planet Mercury.
• It is one of the four Galilean Satellites around Jupiter. It was discovered in 1610 by Galileo Galilei. 
• It orbits Jupiter at a distance of 665,116 miles (1,070,400 km) making it the 7th in distance from the planet.  It is the 3rd Galilean Satellite in distance from Jupiter.
• It takes a little over 7.1 days to orbit Jupiter.
• Ganymede is composed of silicate rock and water ice.
• Ganymede is the only moon in the solar system with its own magnetic field which causes auroras to form around its poles.
• It is tidally locked meaning that the same side always faces Jupiter just as our Moon does Earth. For more information on Tidal locking you can go here.
• It was named after Ganymede who was a hero in Greek Mythology and cup bearer of the gods.
• Ganymede is also has a subsurface ocean of liquid water.

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Several missions have studied Ganymede and there are also some planned in the future.

• Pioneer 10 (launched March 2, 1972) and Pioneer 11 (launched April 5th 1973)
• Voyager 1 (launched Sept 5, 1977) and Voyager 2 (launched August 20, 1977)
• Galileo (launched October 18, 1989)
• New Horizons (launched January 19, 2006)

• Future Mission JUpiter ICy moon Explorer (JUICE) to be launched by the European Space Agency (ESA).

Ganymede is also in orbital resonance with Io and Europa.  Orbital resonance is defined as: orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other, usually due to their orbital periods being related by a ratio of two small integers. (source)

For every orbit of Jupiter by Ganymede, Io orbits Jupiter twice and Europa four times. (see the graphic below)

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Article Sources and for more detailed information:

http://en.wikipedia.org/wiki/Ganymede_(moon)

http://en.wikipedia.org/wiki/Ganymede_(mythology)

http://www.solarsystemquick.com/ganymede.htm

http://en.wikipedia.org/wiki/Tidal_locking

http://science.nasa.gov/missions/pioneer-10-11/

http://science.nasa.gov/missions/galileo/

http://science.nasa.gov/missions/new-horizons/

http://science.nasa.gov/missions/voyager/

http://voyager.jpl.nasa.gov/mission/index.html

http://en.wikipedia.org/wiki/Jupiter_Icy_Moon_Explorer

http://www.lpi.usra.edu/opag/mar2012/presentations/Friday/5_JUICE_Summary.pdf

http://www.newscientist.com/blogs/shortsharpscience/2012/05/ganymed.html

http://journalofcosmology.com/Planets103.html

http://en.wikipedia.org/wiki/Orbital_resonance

http://space.about.com/od/glossaries/g/orbitresonance.htm