The Moon is the only natural satellite on Earth. Its diameter is about 3,476 km, approximately a quarter of that of the Earth.

The mass of the Earth is 81 times greater than that of the Moon. The average density of the Moon is only three fifths of the Earth's density, and the surface gravity is one sixth of that of the Earth.

The Moon orbits the Earth at an average distance of 384,403 km and an average speed of 3,700 km / h. Complete your turn around the Earth, following an elliptical orbit, in 27 days, 7 hours, 43 minutes and 11.5 seconds. To change from one phase to another, or lunar month, the Moon needs 29 days, 12 hours, 44 minutes and 2.8 seconds.

As it takes to take a turn on its axis the same time as to go around the Earth, it always shows us the same face. Although it seems bright, it only reflects in space 7% of the light it receives from the Sun.

After Earth, the Moon is the most studied space body.

In this chapter:

The origin of the Moon: What is the origin of the Moon? Do we know how and when the only natural satellite was formed on the… Read page Moves of the Moon: The Moon is a satellite and, therefore, revolves around the Earth at an average distance of 384… Read page The phases of the Moon: The The phases of the Moon are the different illuminations that our satellite presents in the course of a moon… Read page The eclipses: An eclipse is the darkening of a celestial body by another. As the celestial bodies are not still on the… Read page The lunar surface: The Moon is a world full of mountains, craters and other formations. The lunar surface craters are… Read page Observing the Moon: Observing the Moon is not difficult, since it is the closest astronomical body to Earth… Read page Human Brothers on the Moon: Successful moon landing of unmanned space probes of the American Surveyor and the Soviet series… Read page