MOON      Earth's Satellite

          Mean distance from Earth:  384,400 KM 

          Diameter:                  3476 KM

          Mass:                      0.0123 Earths

          Density:                   3.34 grams / cubic centimeter

          Surface temperature:       248 F to -274 F

          Orbital period (Synodic):  29.53 days

        The Earth and Moon form a double-planet system.  The Moon is the
        closest astronomical body to the Earth and we know more about it
        than any other object in the heavens.  Many surface features are
        visible to the unaided eye, and a pair of binoculars reveals a great
        amount of detail.  A small telescope shows vast seas of lava, large
        mountain ranges and hundreds of craters of all sizes.  Studies of the
        382 kg of lunar rock and soil brought back by the Apollo missions
        have revealed much about the early history of both the Moon and the
        Earth.


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