What about the moon?

stup_id

Critical Thinker
S
Joined
Jun 13, 2005
Messages
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Hello dear people from the forum...

Yesterday I was watching at the nightsky, something I tend to do often because the amazement that the stars and celestial bodies sight has on me... and I just remembered one of the astronomical facts that always amazed me

It's about the moon our companion in this big cosmos... I always was very amazed at the fact that the moon takes the same amount of time in spinning around its axis, than revolving around the Earth.

I always thought about that imagining that it seemed to be very hard that this fact is just a coincidence...

So I was wondering... someone has heard about any physical, astronomical, and geological theory about some reason which explains why the particular movement of moon?

Well.. I'm confident I'll find people with the expertise in this here

See ya!
 
It's not a coincidence.

Two massive bodies will be distorted to some extent by their associated gravitational field. This is known as a "tidal" distortion. If the two bodies are also rotating frictional forces as a result of the tidal distortion will result in a loss of rotational energy. In the moon's case this has progressed to the point that it has stopped rotating (about its own axis) altogether. It is now "tidally locked".
 
I think one could fairly say, tho', that the moon rotates 360 degrees, in relation to the heavens. But rotates 0 degrees in relation to the center of the earth.
 
Iamme said:
I think one could fairly say, tho', that the moon ... rotates 0 degrees in relation to the center of the earth.
Click to expand...
Not quite. You forgot about libration. It lets us see more than half the moon's surface from the Earth's surface, if you're patient and observant.

βPer
 
Just to add to what others have already said, tidal locking is a very common phenomenon in our solar system. Most of the larger moons of Jupiter and Saturn are tidally locked. Mercury is tidally locked with the sun, but, because its orbit is fairly eccentric, it's locked in a 3:2 cycle instead of 1:1. Pluto and its moon Charon are both tidally locked to each other.

One interesting side effect of tidal forces is that, if the satellite is orbiting the "wrong" way (i.e., in the opposite direction of the parent planet's rotation), it will spiral in and crash (or, more likely, disintegrate along the way). This will happen to Mars' moon Phobos and Neptune's moon Triton at some point in the distant future.

Jeremy
 
Stup_id- Full marks for observation! Give that man a cigar.

Welcome to the forum.
 
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