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Obviously with questions about the 1-way speed of light, I have an experiment in mind.

Say you have 2 wheels connected with an axle and you have slots around the edge of each wheel (the slots are aligned). you then send a laser through the slots, and spin the axle. If the light hits the second wheel shouldnt you be able to calculate the 1-way speed of light based on the length of the axle (between the wheels) and the revolutions per minute?

I feel like I must be missing something obvious, but wouldnt this avoid the need for 2 clocks?

Qmechanic
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Tess S
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    "the slots are aligned" - I'm reminded of "the clocks are synchronized". – Alfred Centauri Jul 09 '22 at 00:00
  • i figured that would be the hang up, but i cant rap my head around how this doesnt subvert the issue? the wheels are connected and the slots pre aligned, doesnt this make it a single clock? – Tess S Jul 09 '22 at 01:36
  • you will need very fast rpm unless the wheels are a long way apart. if they are a long way apart, then yes, mechanical sync is a real challenge. – antimony Jul 09 '22 at 02:36

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Aligning the slots is indeed a problem. How do you spin the thing up? If you start from one side, then the slots are aligned if torque propagates down the axle FTL (c.f. Born Rigidity). OK, so you can spin up each wheel independently at a predetermined time with.... synchronized.....clocks. :-(

JEB
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  • what about starting in the middle of the axle? also, im not sure the alignment matters all that much? if theres a straight line through the slots then light should pass through both when spinning slow and can pass through only the first when spinning fast enough right? – Tess S Jul 09 '22 at 01:27
  • if the speed of light is different per direction, then so may be the EM forces providing rigidity, so you cannot guarantee a "straight through" alignment exists. – JEB Jul 09 '22 at 02:19