Jupiter Moon Ganymede
Ganymede
jupiter moon ganymede Natural color view of Ganymede.

Ganymede (Galileo 1996)
Ganymede Enhanced color view of Ganymede showing the bright new terrain and the older dark areas.
Ganymede Facts
  • Ganymede is the 7th moon in distance from Jupiter.
  • It is the largest moon in the solar system.
  • It has a diameter of 3,270 miles (5,262 km) which is larger than Mercury.
  • Ganymede would certainly be classed as a planet if it orbited the sun instead of Jupiter.
  • It orbits Jupiter at a distance of 665,116 miles (1,070,400 km) and takes 7 days 3 hours to make one orbit of the planet.
  • It is the only moon in the solar system known to have its own magnetic field.
  • Ganymede is under the same tidal influences as Io and Europa although at a much weaker level.
  • It is believed that Ganymede has a salt water ocean 124 miles (200 km) below its surface.
  • Ganymede has a low density meaning that even though it is bigger than Mercury it only has half its mass.
  • The moon was discovered in January 1610 by the Italian astronomer Galileo Galilei.

Ganymede's Surface
The surface of Ganymede has two types of terrain. Forty percent is made up of darker areas which are highly cratered. The remaining 60% has lighter areas consisting of grooved terrain. Some of these grooves are over 700 meters (2,000 feet) in height which run for thousands of miles across its surface.

Ganymede's Atmosphere
Much like Europa's atmosphere Ganymede has an extremely thin layer of oxygen covering it. Its also possible that aurorae occur at its poles.

Ganymede's Temperature
Daytime temperatures on the surface average around -113C to -183C (-171F to -297F). At night temperatures plunge even further to around -193C (-315F).
Origin of Name and Life
surface of ganymede
Voyager 1 close up image of Ganymede's surface.

Origin of Name
Ganymede is named after a handsome mortal prince from Greek mythology who was abducted by Zeus to become cup-bearer to the gods.
See Europa for a more detailed explanation.

Life on Ganymede
Chances of life existing in Ganymede are much less than on Europa due to its ocean being much further from the surface.

Images & Video
Ganymede causing aurora on Jupiter
Ganymede causing aurora
Ganymede Flyover
Impact chain
impact chain
Future and Past Missions to Ganymede
Europa Jupiter System Mission
Europa Jupiter System Mission Launch: 2020
Agency: NASA/ESA
A joint venture by NASA and the ESA (Europe) will study Europa and Ganymede using two separate spacecraft. The ESA led Jupiter Ganymede Orbiter (JGO) will map Ganymede's magnetic field and its interactions with Io, Europa and Callisto. It will also set out to characterize the water ocean underneath its surface.
New Horizons
new horizons Launch: January 2006
Arrival: January 2007
Agency: NASA
As well as sending back images New Horizons made topography and composition maps of Ganymede.
Galileo
galileo Launch: October 1989
Arrival: December 1995
Agency: NASA
Galileo made several flybys of Ganymede sending back a whole host of new data. As well as discovering a magnetic field, an ocean underneath its surface was also detected. Galileo also sent back some stunning close up images of the moon.
Voyager 1 and 2
Voyager 2 Launch: August-September 1977
Arrival: April-August 1979
Agency: NASA
Voyager 1 and 2 made successful flybys of Ganymede taking far more detailed images than the previous Pioneer missions. The grooved terrain could be seen and it was also revealed that Ganymede was in fact larger than first thought, replacing Saturn's moon Titan as the largest satellite in the solar system.

Pioneer 10 and 11
Ganymede from Pioneer 10 Launch: March 1972 - April 1973
Arrival: December 1973 - December 1974
Agency: NASA
Pioneer 10 and 11 made successful flybys of Ganymede but only sent back limited data and blurry images such as the one on the left.