- #36
harrylin
- 3,875
- 93
PAllen said:[..] Why, actually, is light different from all other oscillators? If I have perfectly reflecting mirrors, and a beam bouncing between them, and fall with this apparatus from the tower, the light in the beam gets blue shifted? That can't be right either, then you can distinguish free fall from other inertial motion. So light directly received from higher source is blue shifted, but not if reflected back and forth between falling mirrors? I've gotten myself confused about this.]
I reflected a little more on that question... and I now suspect that the question may be faulty! A proper clock (also in a double sense of the word) generates its proper time, and the "clock" of your thought experiment doesn't do that - it uses a fast dying, non-proper signal from another gravitational potential. Note also that there is a difference between free fall and an apparatus at rest at another potential - but that aspect I did not work out.