From: sylvia@not.at.this.address   
      
   On 29/07/2017 9:10 PM, Ernard Hevalier wrote:   
   > Sylvia Else wrote:   
   >   
   >> If one abruptly rotates the plane (analogous to an abrupt switch of   
   >> frame in SR), then the projected length of the rod abruptly changes.   
   >   
   > What is your obsession with abrupt changes. I suspect a lack of control=20   
   > engineering somewhere.   
   >   
   >   
      
   Abrupt changes are easier to handle in thought experiments. While a   
   truly abrupt change is physically impossible, one can make the change   
   arbitrarily rapid so as to bring a physically possible change as close   
   as one likes to the one in the thought experiment.   
      
   The point of a thought experiment is to focus on the central issue. One   
   does need to be careful not to introduce elements that invalidate it,   
   but one also does not need extraneous complications.   
      
   Sylvia.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)