El viernes, 13 de julio de 2018, 0:33:23 (UTC-5), Ed Lake  escribió:   
   > On Wednesday, July 11, 2018 at 8:31:48 PM UTC-5, Ed Lake wrote:   
   >> On Tuesday, July 10, 2018 at 12:56:03 PM UTC-5, Edward Prochak wrote:   
   >>> On Monday, July 9, 2018 at 3:11:05 PM UTC-4, Ed Lake wrote:   
   >>>> [Moderator's note:  Huge amount of quoted text deleted.  Please quote   
   >>>> only enough to provide sufficient context.  -P.H.]   
   >   
   > < snip >   
   >   
   >> [[Mod. note -- As Tom Roberts (& others) have pointed out, in order   
   >> to directly compare clocks A and B, A and B must be colocated for   
   >> the duration of the comparison, i.e., they must be at the same   
   >> position and (be observed by *all* observers to be) moving at the   
   >> same velocity.   
   >>   
   >> If these conditions don't hold, then we can't directly compare A   
   >> and B.  We may be able to compare (say) A to signals broadcast by   
   >> B, but that's a rather different sort of (indirect) comparison.   
   >> -- jt]]   
   >   
   > Sorry, Moderator, but I can make no sense of your post.  It seems   
   > to require having the same observers in two different places at   
   > once.   
   >   
   > The problem is to compare a moving clock to a clock that is considered   
   > "stationary" (or moving at a slower rate).  According to Einstein,   
   > that is done by first placing clocks A and B side by side to make   
   > certain they are identical and synchronized.  Then clock B is moved   
   > away and brought back.  Due to its movement, the time shown by clock   
   > B should then "lag behind" the time shown by clock A.  I.e., clock   
   > B ran at a slower rate WHILE moving.   
   >   
   > How can you compare a moving clock (B) to a "stationary" clock (A)   
   > if "A and B must be colocated for the duration of the comparison"?   
   >   
      
   The moving clock is assumed to be moving at a very high speed (in order to   
   time dilation effects to be observed). So if clock A is moving at speed 0.6c   
   in order to measure the time dilation you need a set of Einstein synchronized   
   clocks located along the path clock A is following.   
      
   This is the only way to check the readings of clock A with the readings of the   
   synchronized clocks, so the clock A reading is directly compared with a given   
   synchronized clock B, as clock A passes through clock B location (at that   
   instant both clocks are colocated).   
      
   Afterwards, the lectures of the synchronized clocks can be compared to   
   determine   
   the time dilation of clock A. The following diagram shows the setup.   
      
   Clock A   
      
   (*) --> v=0.6c   
      
   (B1)....(B2)....(B3)....(B4)....(B5)....(B6)   
      
   Synchronized clocks   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)