Animation showing the relative sizes of the Earth and Moon. The Earth磗 diameter is some 12,742 kilometres, just under four times larger than the Moon磗 3474 kilometres. This makes the Moon an unusually large satellite in the Solar System, indeed it is the largest satellite relative to the size of its planet, and the fifth largest satellite of any planet. The Moon orbits Earth at an average distance of some 385,000 kilometres, some 30 Earth diameters away.