Hi, I'm new here. This question may already have an answer but I didn't find it. Sorry if there's already one. It's a static version of the twin paradox, without travel and without twins. We have 2 circles C and C' that are superposed. C is fixed, with time t and co-ordinate x along the circle, and has circumference S. C' is rotating at constant speed v, with time t' and co-ordinate x'. Following relativity, and ignoring the centrifugal acceleration that can be as small as wanted by increasing the circle size, we have t'=[itex]\gamma[/itex] (t-vx/c2). And now the question: an observer is located at x=S/2. He can be also considered located at x=-S/2. The observation is made at t=0. What time t' does this observer see when he watches the clock of C' located at the same point? Is it -[itex]\gamma[/itex] vS/(2c2) or [itex]\gamma[/itex] vS/(2c2)? Or does he see infinitely many clocks from C' showing [itex]\gamma[/itex] (n-1/2)vS/c2 for n integer?