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Is it possible to speak about changes in a physical constant which is not dimensionless? First to note is of course that the very idea of "a constant having changed" smacks of a (semantic) absurdity. In the present context, however, the notion of "physical constant" is not necessarily understood so strictly as to rule out any "change" outright, as a ...


For instance, take a rigid pole of several AU in length. [...] The person on the opposite end should receive the pushes and pulls instantaneously as no particle is making the full journey. As other answers have pointed out, you can't have perfect rigidity, and the signal would propagate at the speed of sound in the material. If tap a steel rod with a ...

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