From: dr.j.thornburg@gmail-pink.com   
      
   Phillip Helbig wrote:   
   >> It is a misconception that spheres look contracted when moving at   
   >> relativistic speeds:   
   >>   
   >>  A. Lampa, _Z. f. Physik_, 27, 138, 1924.   
   >>  J. Terrell, _Phys. Rev._, 116, 1041, 1959.   
   >>  R. Penrose, _Proc. Camb. Phil. Soc._, 55, 137, 1959.   
   >>   
   >> I can turn around in a second but the relative motion of the Moon, much   
   >> faster than the speed of light, doesn't correspond to the notion of   
   >> relative motion normally discussed in SR.   
      
   Luigi Fortunati  wrote:   
   [[question about an apparent paradox involving special relativity   
   and a rotating reference frame]]   
      
   I think the underlying cause of Luigi's apparent paradox may be that   
   special relativity implicitly assues that the geometry of space is   
   Euclidean... but the geometry of a rotating reference frame is non-Euclidean.   
   (The non-Euclidean nature of rotating reference frames results in things   
   like the Sagnac effect, the Ehrenfest paradox, etc.)   
      
   There are interesting and relevant discussions in   
     https://en.wikipedia.org/wiki/Sagnac_effect   
     https://en.wikipedia.org/wiki/Ehrenfest_paradox   
     https://en.wikipedia.org/wiki/Born_coordinates   
      
   --   
   -- "Jonathan Thornburg [remove -color to reply]"    
      currently on the west coast of Canada   
      "!07/11 PDP a ni deppart m'I !pleH" -- slashdot.org page footer, 2022-10-16   
      "eHpl !'I mrtpaep dnia P PD1 /107" -- slightly more plausible message   
                                            given PDP-11 little-endian byte order   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)