Lunar Spin Down and Orbit
The earth has a natural moon. That moon's "year"
is the time it takes it to make one trip around the earth. Our
moon also has a "day," the time it takes to rotate once about its
own axis. Our moon's "year" is exactly equal to its day. Not 99%
the same. Not 99.999% the same but 100.000000000000000....% the
same. This explains why the same face of the moon always is
exposed to the earth.
My question is why is this so? In theory, would it be possible to
place a huge rocket on the moon oriented at 90 degrees to a radial
line from the rocket to the moon's center of gravity and change
the duration of the moon's day, and thus forcing other portions of
the moon's surface to face the earth?
The answer is a term called rotational lock. The Earth's gravity
slows the Moon down until it is in rotational lock with the Earth
and the rotation is as it is. Actually it is not 100%; there is a
I guess a big rocket could give us a different face, but it would
have to be awfully big!
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Update: June 2012