From: edprochak@gmail.com   
      
   On Tuesday, July 10, 2018 at 3:33:02 AM UTC-4, Ed Lake wrote:   
   > On Monday, July 9, 2018 at 2:13:03 PM UTC-5, Edward Prochak wrote:   
   > > On Saturday, July 7, 2018 at 9:35:41 PM UTC-4, Ed Lake wrote:   
      
   > >> A stone dropped from a moving train cannot drop straight down because   
   > >> inertia will cause it to move with the train until gravity stops   
   > >> it.  The observation that the stone fell straight down was "incorrect"   
   > >> because it was inconsistent with the laws of physics.  When you   
   > >> understand how events can APPEAR inconsistent with the laws of   
   > >> physics while still obeying the laws of physics, then all observers   
   > >> can agree on what actually happened.   
   > >>   
   > >> Ed   
   > >   
   > > You still persist in this "correct'/"incorrect" paradigm   
   > > that begs for a god-like reference frame.   
   >   
   > No, it just requires being able to tell the difference between what is   
   > "real" and what is an "illusion."  You may think that the train you are   
   > on is stationary and the railroad station and embankment outside are   
   > moving, but that is just an "illusion."  If you understand that energy   
   > was required to make the train move, and the amount of energy used by   
   > the engine could not possibly make the planet move while the train   
   > stands still, then you can understand how to tell the difference between   
   > an "illusion" and reality.   
      
   You fail to keep in mind that the train is a star or planet   
   and the embankment is another star or planet. IOW, you are   
   making reference to an absolute frame, the planet Earth,   
   in the above comment.   
      
   The point Tom and I are both trying to make is:   
   there is no illusion!   
      
   >   
   > Of course, it can be argued that it is also an "illusion" that the   
   > embankment and station are standing still, since both are moving as the   
   > earth spins on its axis and travels around the center of the galaxy at   
   > 486,000 miles per hour, but the energy produced by the train's engine   
   > has nothing to do with that movement.  So, it all depends upon what you   
   > are arguing.   
      
   I am arguing that both observations are real.   
   Both observations are consistent with SR.   
      
   >   
   > >   
   > > you are right, unless, of course, the train is   
   > > standing still on the tracks! ;)   
   >   
   > My statement was about "A stone dropped from a moving train".  Note the   
   > word "moving."   
   >   
   > > Or in my two train example,   
   > >  both trains move with the same velocity.   
   > >   
   > > Ed P.   
   >   
   > Your experiment was about "2 trains with windows only on the side facing   
   > the other train. Nothing else to reference. Tracks and embankments are   
   > out of sight.  Of course also extremely smooth ride, no vibrations to   
   > indicate movement."   
      
   yes, or if you prefer, two space trains on an interstellar line   
   >   
   > What is the purpose of such an experiment?  To show that you can create   
   > a situation where no one can tell what is really happening?  Everyone   
   > knows that.  You can do it by performing an experiment in a closed lab   
   > where you have no way to know if the lab is moving or not.   
   >   
   > The point is: If you CAN tell who is moving (by opening the window, for   
   > example) then you can ALSO determine who is moving faster than whom.   
      
   There is the point:   
   you can NOT tell who is moving in any absolute manner.   
   There is no window in this universe to open.   
      
   > You can do it by comparing clock tick rates (if you have identical   
   > clocks).  The person whose clock ticks slowest is the person who is   
   > moving fastest.   
   >   
   > Ed   
      
   This last point is not clear. You seem to be taking a vote   
   with multiple observers. So Alice, Bob, and Dan all   
   agree that Charles has the slowest clock and therefore   
   is moving fastest of relative to the other three.   
   That is a valid observation.   
      
   But the complimentary conclusion that Charles, Bob,   
   and Dan all agree that Alice has the fastest clock   
   does not lead to the conclusion that Alice is not moving.   
   Alice is still at best only an agreed-to reference frame.   
      
   And one more point:   
   It may be that the others are moving as a group away   
   from Charles. The observations of the clocks will   
   be the same. You really cannot know the absolute motion.   
   And it isn't an illusion.   
      
   HTH,   
     Ed   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)