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Physics, Astronomy & Cosmology / Re: Is time dilation present inside of a hollow sphere?
« on: 25/04/2017 20:17:45 »But where is the mechanism by which a clock can be slowed inside a hollow sphere? You have a volume of space inside in which there is no Spacetime curvature whatsoever (apart from the trivial amount produced by a clock sitting in the middle of that space), but a clock runs slow there even though there is no way for its depth in the gravity well to impose itself on the clock's functionality. If you add more material to the shell of the hollow sphere, the clock will run even slower, but again there is no mechanism to make this happen. How is this gaping hole in the theory normally addressed?When we talk about a clock "running slower" we mean as measured from some reference frame. In this case we can choose some point far removed from our sphere. For this observer, it is not the space-time curvature at the clock's location that determines the time dilation, but the effect of the space-time curvature between him and the clock. For him, the clock is deeper in the gravity well than he is. If you add material to the sphere, you are increasing the curvature he measures between himself and the clock, deepening the gravity well and thus the gravitational time dilation he would measure for it.
Gravitational time dilation is not due to some physical effect acting on clocks, but to how clocks compare their tick rates across a gravitational potential.