On Thursday, October 24, 2024 at 12:01:30 AM UTC-6 Jesse Mazer wrote:

On Wed, Oct 23, 2024 at 9:03 PM Alan Grayson <[email protected]> wrote:



On Wednesday, October 23, 2024 at 6:03:58 PM UTC-6 Jesse Mazer wrote:

On Wed, Oct 23, 2024 at 7:10 PM Alan Grayson <[email protected]> wrote:



On Wednesday, October 23, 2024 at 4:47:13 PM UTC-6 Jesse Mazer wrote:

On Wed, Oct 23, 2024 at 6:31 PM Alan Grayson <[email protected]> wrote:



On Wednesday, October 23, 2024 at 1:55:13 PM UTC-6 Brent Meeker wrote:

The fact that you never specify whether "synchronized" means "set to the 
same time" or "caused to run at the same rate" or both, makes me think you 
don't understand your own question.

Brent


I meant when juxtaposted, to set at the two clocks at the same time, and 
then synchronized throughout each frame. Then I expect, but am not certain, 
that the rates in the two frames will be the same. AG


"Synchronized" only has meaning relative to a particular frame's definition 
of simultaneity--since the frames disagree on simulataneity, you can 
momentarily set all clocks so that they read the same time at the same 
moment relative to one frame, but you can't do this in both frames. And 
whichever frame you pick, unless you artificially adjust the ticking rate 
of the clocks moving relative to that frame to "correct" for time dilation, 
the moving clocks won't stay synchronized with the clocks at rest in that 
frame.

Jesse


As I see it, when the clocks are juxtaposed, a comparison of any clock in 
one frame, will read the same time as the corresponding clock in the other 
frame, that is, corresponding with position as they pass each other. And 
since the frames are moving with the same velocity wrt each other, I don't 
see the role of simultaneity in changing the rate of any clock in any 
frame. What I think this scenario shows, is that time dilation doesn't 
exist. AG 


But that's wrong according to relativity, and the Lorentz coordinate 
transformation is mathematically/logically consistent, and the prediction 
that the laws of physics work symmetrically in these different frames (so 
that readings on natural physical clocks at different locations will align 
with coordinate time in their rest frame, assuming they are synchronized 
according to the Einstein convention at 
https://en.wikipedia.org/wiki/Einstein_synchronisation ) has held up 
experimentally. I once made a diagram showing two rows of clocks in motion 
relative to each other, synchronized according to Einstein's convention, so 
people can see how it works--see 
https://physics.stackexchange.com/a/155016/59406

Jesse


Jesse; I'll check out your links, for sure. I will just say now that time 
dilation can be established using a rest frame and moving frame, but in my 
model there is no rest frame; both frames are moving. AG 


In relativity "rest frame" is only used in a relative sense, there is no 
objective truth about which frame is called the "rest frame" and which 
frame is "moving". For example if you have two clocks A and B in relative 
motion, you can calculate things from the perspective of the coordinate 
system where A's coordinate position doesn't change with time which is 
called "A's rest frame", but you can equally well calculate things from the 
perspective of the coordinate system where B's coordinate position doesn't 
change with time which is called "B's rest frame", and both calculations 
should agree in their predictions about all local events eg what readings 
show on both clocks at the moment they pass next to each other (I 
illustrated this with a few clocks in the diagrams from my link).

Jesse


TY. Yes, I am aware of what you wrote. That's why I tried to come up with 
an example where there is no frame identified as the rest frame. I will 
look at your diagrams today. I think Brent makes the same point with world 
lines. AG


 



On 10/23/2024 6:00 AM, Alan Grayson wrote:

In this scenario, is there any contradition with the principles of SR? 
Suppose there exist two inertial frames, moving in opposite directions with 
velocity v < c along the x-axis, where one clock of each frame is initially 
located one unit, positively and negatively respectively from the origin, 
and when these clocks are juxtaposed at the origin, the multiple set of 
clocks in both frames can be synchronized? Does this scenario imply an 
unwarranted affirmation of simultaneity? 

TY, AG

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