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Name: Darell
Status: educator
Age: 40s
Location: N/A
Country: N/A
Date: 2000-2001


Question:
Regarding the "aether", I understand that the concept was dropped from physics due to the acceptance of the theory of relativity and experiment by Michaelson and Morley showing that the speed of light is a constant despite linear motion. My question is how to interpret the following thought experiment: imagine that we are in an "Einstein elevator" i.e. we are enclosed so we have no external referents. Relativity implies that we cannot distinguish gravitational force acting on our elevator from acceleration. OK, but consider this: suppose I am in the elevator and I have 2 small weights connected by a spring scale. Assume for simplicity that there is no gravity or linear acceleration so I am functionally weightless. Now at the start of the thought experiment I hold the scale by its center of gravity, it will measure 0. Now I give the weights and scale a spin about their center of gravity. The scale now indicates a force. But the scale will continue to indicate a force even if the elevator is spun in synchrony with the scale. This indicates that rotational motion is not relative, it is absolute and it points to an absolute frame of reference...no?


Replies:
No. Different viewers will still disagree on the linear speed of the scale system as a whole, so it doesn't define an absolute frame of reference as the aether was thought to do. It's true that everyone will agree the scale system is rotating, and it's true this is because rotational motion involves acceleration, which is not relative.

Tim Mooney



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