According to Einstein (e.g. in his book The Meaning of Relativity), a clock rotating about a central clock will be judged by the central clock to run slower than the central clock. This means that a signal sent by the central clock will be perceived by the rotating clock as being of a higher frequency. If the central clock sends a very low frequency radio signal with a wavelength of 32000 metres, then at the right linear speed for the rotating clock it receives this same wave as only 0.12 metres in length, which is a microwave. Now a microwave would leave a telltale mark on the rotating clock! OK...here comes the hot dog. To confirm that waves leave visible marks, you can try a home experiment. You remove the turning plate from a microwave oven and place a hot dog inside the oven. After 2 minutes or so some bubbling will appear on the hot dog; the total length of the bubbling will be about 0.12 metres, confirming the length of one microwave. Therefore, in the frame of the rotating clock a meter stick would measure each wave as contracted compared to the waves received in an inertial frame. So far so good...but.... As each wave sent from the inertial central position was 32000 metres in length, and now the wave mark on the rotating clock ( or the hot dog if you prefer) is only 0.12 metres, then, to an idiot, the rotating clock has expanded in relation to that one wave. Equally, we may say the wave has contracted in relation to the rotating clock. You know the wave-mark on a hot dog is real, right? So, in view of the principle of length contraction, which I do not dispute, what is the “fabric” that the “expanding” meter stick in the rotating frame is measuring? Is it a worldline in Minkowski space? Is it direct evidence of length contraction itself? What should we call this metric/dimension/property/whatever ? When I asked this problem elsewhere I was lectured "moving bodies contract, not expand". Yep. I know that. But this is a different perspective altogether. I trust someone has actually thought of this problem before, or can point to an example in a reference.