Question

Why do you see only one side of the Moon from Earth

Answer 1

Because the Moon rotates on its axis at the same rate that the Moon orbits the Earth, a situation known as synchronous rotation or tidal locking. The Moon is directly illuminated by the Sun, and the cyclically varying viewing conditions cause the lunar phases.

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Answer 2

Because the sun is only shining on one part of the moon and the other side is the dark side and it blends in with the dark sky. 

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