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An astronaut camps on the moon for a period of one month as per the earth’s calendar. What would be the path of the earth seen by the astronaut in the lunar sky?

(A) The earth remains approximately at a fixed altitude and direction.

(B) The earth completes one revolution parallel to the lunar horizon in one month.

(C) The earth completes one revolution from east (direction of rising sun) to west (direction of setting sun) in one month.

(D) The earth completes one circle around the Pole Star in one month but never goes below the horizon.

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closed as off topic by David Z Apr 24 '12 at 15:24

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Believe it or not, but it is (A). For some reason Moon is rotating about its own axis with the same rotation frequency as it is rotating around Earth, so we always see the same side of the Moon.

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