Asia Tooke and Avery Morgan It is the largest satellite in our solar system with three whole layers: an iron, metallic core that generates its magnetic field, a rocky mantle, and its shell, which is chiefly composed of ice. There is some Oxygen in the atmosphere, but its too thin to support life. Its lumpy! This means that there are probably rock formations beneath the ice. Ganymedes Bright Limb Galileo Regios furrowed region Its forty percent cratered area, and sixty percent lightly grooved terrain from tensional faulting or release of water beneath the surface. Some grooves are up to 700 m high. The dark cratered area is probably the original crust of the satellite. The craters are flat, probably because of the soft, icy ground. Galileo Regio is the largest area on Ganymede. Khensu Crater Grooved terrain Galileo, at first, called the moons numerically after the Medici family. In the mid-1800s, Ganymede as well as the other Galilean moons were renamed so as to avoid confusion that could arise with naming the moons numerically. Ganymede in Greek mythology was a very pretty boy that was disguised as an eagle by Zeus and brought to Mount Olympus to be the cupbearer of the Gods.