Quote:
Originally Posted by Nesti
This is precisely why I said earlier that this is a composite of motions. There is a spin, but it is an apparent spin. This is actually a 'Parallel Transfer' of a body, within a geodesic, around a central mass; like a race track within a gravitational field where the outer wheels must cover a greater distance than the inside wheels; there is a consequence. The Moons spin comes as a direct relationship between it's orbital velocity and the field. The Tidal Lock is probably a feature of how the two fields (Moon and Earth) interact together.
The spin of the Die is attributed to it's orbit around the Earth, but the reason why the Die will always face the Earth (if positioned that way and left untouched) comes down to General Relativity...you see the space and time in which the Die is positioned within the geodesic pathway contains conservation of angular momentum (all laws actually) BUT, the geodesic is a curved path around the Earth, so the space spins around the Earth, not the Die (the space is bent to conform with the filed curvature)...this also means that the 6 face is being compressed and the outside face (opposite to the 6) is being stretched...the gravitational field is trying to turn it into a pie wedge. As the Die orbits the Earth the space which it occupies is rotated in sync with the curvature, so the Die isn't spinning, the space and time which the Die occupies is being warped, the net affect being tidal forces acting upon the Die and a change to the Die's orientation without any effort at all. This is also why satellite moons get crushed in orbit around gas giants to form rings of dust.
A Tidal Lock seems to be both a conservation tendency and a warping issue.
So is the Moon spinning???
I believe it has an apparent spin, but it is also stationary within the gravitational field.
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If the die is on a geodesic path it is not subjected to tidal forces.
What actually happens is that the Earth's rotation causes the die to deviate from it's geodesic path (the Lense-Thirring effect). This subjects the die to an external force resulting in the orbital plane of the die to tilt in the same direction as the rotation of the Earth.
This however has nothing to do with the topic.
The fact is the moon spins on it's axis. Tidal locking results in transferring some of the Earth's rotational energy to the moon. This has caused the moon's axial spin period to be equivalent to it's period of rotation around the Earth.
Regards
Steven