It is the largest moon in the solar system.
It has heavily cratered dark sections and grooved light sections. It also is surrounded by a magnetic field and a small amount of ozone. Scientists speculate that, like Europa, it has a very thin oxygen atmosphere and that, like Callisto, it has a rocky core and a mantle containing water and ice. It is the largest moon in the solar system. Name this Galilean satellite discovered the day after Europa, Callisto, and Io.
It has heavily cratered dark sections and grooved light sections.
Ganymede