Moon

Article

The Moon is Earth's only natural satellite and the fifth-largest satellite in the Solar System. It orbits Earth at an average distance of about 384,400 kilometres and has a diameter about one quarter that of Earth.

The Moon formed more than four billion years ago, most likely from debris produced by a giant impact involving the early Earth. Its surface contains heavily cratered highlands, darker volcanic plains called maria, mountains, valleys, and polar regions containing water ice.

The Moon rotates once in approximately the same time that it orbits Earth, so nearly the same hemisphere always faces Earth. Its orbital motion produces lunar phases, eclipses, tides, libration, and several overlapping monthly and long-term cycles.

Human exploration began with robotic missions and was followed by crewed Apollo landings between 1969 and 1972. Continuing observations and missions study lunar geology, resources, orbital history, and the Moon's influence on Earth.

Source details and credits

• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Moon