Earth and Moon, composite image. The Earth has a diameter of 12,742 kilometres, while the Moon has a diameter of 3475 kilometres. The Moon's diameter is 27 percent of the Earth's, and its mass is less than 2 percent of the Earth's. The Earth has an atmosphere and oceans of water, and supports life, while the Moon is a cratered, barren world with extremes of surface temperatures. The distance between the Earth and Moon is not shown to scale here: the Moon orbits the Earth at a distance of around 385,000 kilometres.