The Moon is an astronomical body that orbitsEarth as its only natural satellite. It is the fifth-largest satellite in the Solar System, and the largest among planetary satellites relative to the size of the planet that it orbits (its primary). The Moon is, after Jupiter‘s satellite Io, the second-densest satellite in the Solar System among those whose densities are known.

Useful facts

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Additional facts to know.

  1. The Moon is in synchronous rotation with Earth.
  2. The Moon’s average orbital distance is 384,402 km (238,856 mi).
  3. The Moon was first reached in September 1959 by the Soviet Union‘s Luna 2
  4. Both the Moon’s natural prominence in the earthly sky.

Final steps

The Moon is a very slightly scalene ellipsoid due to tidal stretching, with its long axis displaced 30° from facing the Earth (due to gravitational anomalies from impact basins). 

The dark and relatively featureless lunar plains, clearly seen with the naked eye, are called maria (Latin for “seas”; singular mare), as they were once believed to be filled with water;[66] they are now known to be vast solidified pools of ancient basaltic lava. Although similar to terrestrial basalts, lunar basalts have more iron and no minerals altered by water.[67]