Ganymede A satellite of Jupiter and the largest moon in the Solar System. It is the seventh moon and third Galilean satellite outward from Jupiter. Completing an orbit in roughly seven days, Ganymede participates in a orbital resonance with the moon
Ganymede, the seventh moon of Jupiter. It is the largest moon of Jupiter and in the solar system. Ganymede has a diameter of miles kilometers), larger than the planet Mercury. It is the only moon known to have a magnetic field.
NASA’s Hubble Space Telescope has the best evidence yet for an underground saltwater ocean on Ganymede, Jupiter’s largest moon. The subterranean ocean is thought to have more water than all the water on Earth's surface.