Ganymede, the largest moon in the solar system, is about 3,273 miles (5,268 kilometers) across making it larger than the planet Mercury, although it has only half of the mass of Mercury, classifying it as low density. It has an ocean of liquid water beneath its surface composed of a thick crust of ice. Ganymede may actually have more water than earth. Scientists believe that the ocean is about 60 miles deep, 10 times deeper than earth oceans. Ganymede is 665,000 miles from Jupiter and makes a complete orbit every seven days. Ganymede is greatly affected by Jupiter's gravity and magnetic field due to its close proximity.

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