Ganymede, or Jupiter III, is the largest and most massive of the Solar System’s moons. The ninth-largest object in the Solar System, it is the largest without a substantial atmosphere. It has a diameter of 5,268 km (3,273 mi), making it 26% larger than the planet Mercury by volume.] Possessing a metallic core, it has the lowest moment of inertia factor of any solid body in the Solar System and is the only moon known to have a magnetic field.

« Back to Glossary Index