I was just reading about the experimental proof of time dilation using some atomic clocks on aeroplanes. Which got me thinking...(adsbygoogle = window.adsbygoogle || []).push({});

Consider a rotating disk. Say it is a few hundred metres radius (although its size makes no difference to this question, it makes it easier for me to visualise). Clamp down an atomic clock onto the disk platter located at a point on the circumferential edge and call it point A. Strap a willing observer to that clock. Do the same again but put a clock and observer near to, but not at, the centre of the disk and call it point B. Put another clock and observer next to (but not on) the rotating disk and call it point C. Spin the disk as fast as possible for some long time and then slow to a halt.

1. There is no speed difference between point A and B i.e. A and B never move relative to each other. Therefore there will be no time difference between the clocks at A and B.

2. Points A and B do move relative to point C, but with different speed profiles. So, there will be different time difference between clocks A and C and clocks A and B.

Statement 1. says that clock reading are the same at A and B. Statement 2. implies that the clock readings at A and B are different. One or both statements can not be true.

What am I missing? (other than a better understanding of special relativity!)

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# Rotating disks and time dilation

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