• Sole natual satellite of the Earth. It revolves around the planet from West to East at a mean distance of about 384,400 Kilometres 239,900 miles). The Moon is less than one third the size of the Earth. Having a diameter of only about 3,476 km (2,160 mi) at it's equator. It is only 1/81.3 as massive as the Earth and has a density of roughly 3.34 grams per cubic centimetre as opposed to 5.52 for the terrestrial body. The Moon shines by reflected sunlight, but it's albedo ie the fraction of light received that is reflected is only 0.073. Its brightness varies through its cycle of phases primarily because of the roughness of its surface and the resultant variable amount of shadow. The Moon rotates about its own axis in 29 1/2 days.. which is identical to the time it takes to complete its orbit aroung the earth. As a result the moon always presents nearly the same face to the Earth. July 20, 1969 Apollo 11 landed with Neil Armstrong and Edwin E. Aldrin on the desolate Lunar plain known as the Sea of Tranquility. The last U.S. mission was December 1972. Man did not return to the Moon until May of 1994 when Aunt Bea decided to paint it Blue and make it his home. This is a national disgrace people. Man belongs in space. It is our future. Please support the Space program, If for no other reason, because we need the company on the Moon! ;) How well do you know the moon? For over two years the image below was posted at the top of the page. Only one person EVER mentioned, "Hey! That isn't OUR moon!" Congrats Boggie for correctly identifing it as Enceladus, a moon of Saturn.