Composition He posseses a small metallic core and large amounts of water ice, making him less dense than most other objects in the solar system. He is larger in size than the planet Mercuryball at 5268 kilometers in diameter but is only half the mass due to his low density. Despite this, Ganymede is the most massive moon in the Solar System, having about 3% the mass of Earth.
Orbit - Rotation
Ganymedeball orbits around Jupiterball every 7.16 days, at a distance of just over a million kilometers. It has an extremely low eccentricity of 0.001, having among the lowest eccentricities of any object in the Solar System. He is in a 4:1 resonance with Io and a 2:1 resonance with Europa. Ganymedeball is tidally locked to Jupiterball, meaning the same side of Ganymede ball will always face his father, and that his rotational period is also exactly 7.16 days.