Quote:
Originally Posted by sjastro
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.
Regards
Steven
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That doesn't make sense Steven. What you are saying is that a moon like Io is being shifted from it's geodesic path which creates the tidal forces rather than Io's spin subjecting Io to changing tidal forces across it's regions. If Io were locked like our moon there would be no volcanic activity as the tidal effects would be static, and that's because the regions of Io would be with respect to Jupiters field. But Io must spin because the tidal forces act around Io are squeezing it at different rates (harder closer to Jupiter), and thus creates internal heating, like heating up a squash ball. Tidal forces are present because a spinning body traveling within the geodesic will have matter which oscilates toward the field centre and then back out within a band which is the diameter of the object that is spinning. So a single point of the surface of the object would take a path much like a nail in a car tire if tracked from a stationary observer on the side of the road, It oscilates between the road surface and the tire height and travels but the band travels in a straight line...but the Die has an overall curvature (around the Earth) because it's in orbit.
Tidal forces would still be acting upon the Die regardless of whether it is spinning or not, but the
effects of the tidal forces only become
apparent when an object spins because the tidal forces then get to act upon different regions of an orbiting body, like energy from the Sun creates the weather because the Sun's energy gets distributed around the Earth's surface and energy like to migrate to lower regions (ignoring seasons).
The only other way would be if the orbiting body had an elliptical path, where the distance from the field centre varied...where an orbiting body would experience greater field curvature closer to Earth and less curvature farther away from Earth...this too should create internal heating as the tidal forces are changing, even if an elliptic Moon was Tidal Locked, it would still heat up because the field curvature would be more pronounced closer to the Earth.
I agree that Tidal Locking is separate to the geodesic, but the 6 face of the die would be kept facing Earth if the die is undisturbed in the geodesic...in orbit. Tidal Locking seems only to be an energy transfer within the field, like regions of higher energy must flow to regions of lower energy, and thus creates a connection between two parts of the system (like what I said about thermodynamically coupled parts...they are coupled because energy is transferring from regions of higher energy flowing to regions of lower energy); the transfer IS the coupling.