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Moon drifting away?

  1. May 21, 2012 #1
    why is the moon drifting away from the earth? isnt it general relativity suggests that itll move towards the earth?
  2. jcsd
  3. May 22, 2012 #2


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    If you are referring to gravitational radiation shrinking the orbit, the effect is pitifully small compared to the tidal effects which cause the moon to recede.
  4. May 22, 2012 #3


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    Tidal friction. The Earth's rotation is more rapid (24h) than the moon's orbital motion (28d). The friction of the tides tries to equalize these periods. It tends to slow the Earth down, pulling it backward and decreasing its angular momentum. Conversely the friction pulls the moon forward, increasing its angular momentum, thus causing the diameter of the orbit to increase.
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