From: fortunati.luigi@gmail.com   
      
   > [[Mod. note -- By definition, the travelling twin looking through their   
   > telescope at Earth sees the event where Earth's worldline intersects the   
   > travelling twin's backwards light cone. The travelling twin's backwards   
   > light cone depends only on the event at its apex, NOT on the travelling   
   > twin's velocity. Therefore, the intersection of that light cone with   
   > Earth's worldline (i.e., the event that the travelling twin sees when   
   > looking at Earth through their telescope) depends on the travelling   
   > twin's position but NOT on the travelling twin's velocity. Therefore,   
   > the travelling twin sees little visible change when looking at Earth   
   > during their (the travelling twin's) turnaround.   
   > -- jt]]   
      
   I have reflected intensely on the replies received from all of you and I thank   
   you from the bottom of my heart.   
      
   I realized that I had made a mistake: that of having (me too) considered the   
   change of direction to be almost instantaneous.   
      
   Apart from the fact that one does not pass from the speed v=0.866c to the   
   speed v=-0.866c in an instant, it must be said that, if it were possible to do   
   so, none of what I said could happen during the reversal of direction because   
   nothing happens in zero    
   time.   
      
   So, I'll have to revise my example by assigning a precise time duration to the   
   reverse.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)