| About the Moon
The Earth's only natural satellite, the Moon is more than one quarter the size of Earth itself. Because of its smaller size, the Moon has less gravity. You weigh one-sixth what you do on Earth on the Moon.
There are many interesting surface features such as craters, mountain ranges, rilles, and lava plains. The Moon's interior is made up of a top rocky solid layer, perhaps 800 km thick. Beneath this layer is a partially molten zone. Although it is not known for certain, many believe the Moon has a small iron core, even though the Moon has no magnetic field. By studying the Moon's surface and interior, geologists can learn about the Moon's geological history and its formation.
The footprints left by Apollo astronauts will last for centuries because there is no wind or erosion factors on the Moon. The Moon does not possesses any atmosphere, so there is no weather as we are used to on Earth. Because there is no atmosphere to trap heat, the temperatures on the Moon are extreme, ranging from 100° C at noon to -173° C at night.
The Moon doesn't produce its own light, but looks bright because it reflects light from the Sun. Think of the Sun as a light bulb, and the Moon as a mirror, reflecting light from the light bulb. The lunar phase changes as the Moon orbits the Earth and different portions of its surface are illuminated by the Sun.
| Quick Facts
Year Discovered : Unknown
Discoverer : Unknown
Distance from planet : 384,400 km (238,855.086 miles)
Diameter : 3,476 km (2,159.886 miles)
Orbital Period : 27.322 days