How Does Clock Synchronization Work in Different Dimensions?

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Discussion Overview

The discussion revolves around the topic of clock synchronization in different dimensions, particularly focusing on Einstein synchronization and alternative methods. Participants explore the implications of varying synchronization parameters and the connection to the speed of light, including isotropy and anisotropy in both inertial and non-inertial frames.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants express confusion regarding the implications of using non-standard synchronization methods and how they relate to the speed of light in different directions.
  • Others argue that if light were quicker in one direction than another, it would hinder the operational ability to synchronize clocks using light signals.
  • Some participants assert that experimental evidence shows the one-way speed of light is isotropic, while others challenge this, claiming it is a convention without experimental proof.
  • Grunbaum's ε-synchrony is proposed as a method for synchronizing clocks in inertial frames, with the caveat that this may lead to different clock readings based on the chosen synchronization parameter.
  • There is a discussion about how specifying light speed in one direction affects the speeds in other directions, with some suggesting that 3-dimensional treatments require consideration of multiple independent directions.
  • Participants mention a spectrum of tests on one-way light speed anisotropy, with some claiming that many experimentalists would disagree with the assertion that no experiments can demonstrate isotropy in inertial frames.
  • One participant requests further clarification on the differences between 1-dimensional and 3-dimensional synchronization analyses.

Areas of Agreement / Disagreement

Participants do not reach consensus on the isotropy of the one-way speed of light or the validity of different synchronization methods. Multiple competing views remain regarding the implications of these concepts.

Contextual Notes

Limitations include the dependence on definitions of synchronization methods and the unresolved nature of the experimental evidence regarding one-way light speed anisotropy.

analyst5
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This is basically a follow-up to some questions from a previous thread regarding Einstein synchronization and other methods. I don't understand the alternative methods when the synchronization parameter isn't 1/2 and its connection to the speed of light. Basically it means that the light is quicker in one direction than the other, but there are is an infinite number of directions, so I don't understand which light rays are quicker than the others. For instance, let's suppose that we sync two distant clocks with a non-standard method. So the light from the front, in one case, may be faster than the light coming from the back, right? How would the light mentioned in this case behave in other directions regarding its velocity?
 
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analyst5 said:
This is basically a follow-up to some questions from a previous thread regarding Einstein synchronization and other methods. I don't understand the alternative methods when the synchronization parameter isn't 1/2 and its connection to the speed of light. Basically it means that the light is quicker in one direction than the other, but there are is an infinite number of directions, so I don't understand which light rays are quicker than the others. For instance, let's suppose that we sync two distant clocks with a non-standard method. So the light from the front, in one case, may be faster than the light coming from the back, right? How would the light mentioned in this case behave in other directions regarding its velocity?

If light "were quicker in one direction than in the other", then there would be no operational way of synchronizing clocks by using light signals. Fortunately, experiment shows that light speed (one way) is isotropic. Even if it weren't, you could still synchronize clocks (via slow clock transport, as they did it for the ill-fated "neutrino faster than light" experiment), you just couldn't use light signals.
 
xox said:
If light "were quicker in one direction than in the other", then there would be no operational way of synchronizing clocks by using light signals. Fortunately, experiment shows that light speed (one way) is isotropic. Even if it weren't, you could still synchronize clocks (via slow clock transport, as they did it for the ill-fated "neutrino faster than light" experiment), you just couldn't use light signals.

Is it also isotropical in non-inertial frames, but can have a different value than c?
 
xox said:
If light "were quicker in one direction than in the other", then there would be no operational way of synchronizing clocks by using light signals.

Yes there is. One simply uses Grunbaum's ##\epsilon##-synchrony for inertial frames.

xox said:
Fortunately, experiment shows that light speed (one way) is isotropic.

No it doesn't. There is no experiment that can show the one-way speed of light is isotropic in inertial frames. The isotropy of the one-way speed of light in inertial frames is purely a convention.
 
WannabeNewton said:
No it doesn't. There is no experiment that can show the one-way speed of light is isotropic in inertial frames. The isotropy of the one-way speed of light in inertial frames is purely a convention.


There is a very large spectrum of tests on OWLS anisotropy, here is a very small sample. I can provide you with many more tests of OWLS anisotropy.
 
WannabeNewton said:
Yes there is. One simply uses Grunbaum's ##\epsilon##-synchrony for inertial frames.

While the predictions derived from such departures from Einstein synchronization produce theories experimentally indistinguishable from SR, the defined clock time varies from Einstein's according to the distance in a specific direction.(see Zhang's book). So, in earnest, the clocks aren't synchronized anymore because they show different times.To make matters worse, the difference varies with distance.
 
Last edited:
WannabeNewton said:
Yes there is. One simply uses Grunbaum's ##\epsilon##-synchrony for inertial frames.



No it doesn't. There is no experiment that can show the one-way speed of light is isotropic in inertial frames. The isotropy of the one-way speed of light in inertial frames is purely a convention.


Ok, so if we specify the light speed in one direction and automatically the speed in the opposite direction, how do speeds of light in other directions follow from that?
 
analyst5 said:
Ok, so if we specify the light speed in one direction and automatically the speed in the opposite direction, how do speeds of light in other directions follow from that?

Elementary treatments tend to stick to 1-dimensional expositions however the same thing you do for 1-dimension applies to 3-dimensions except now you have to treat 3 independent directions as opposed to just 1.
 
xox said:
So, in earnest, the clocks aren't synchronized anymore because they show different times.To make matters worse, the difference varies with distance.

That doesn't mean they aren't synchronized as the choice of ##\epsilon## is what defines the synchronization of clocks. The clocks may show different times according to the Einstein synchronization convention but not according to my other choice of ##\epsilon##. None of your objects have anything to do with whether or not one-way anisotropic speed of light synchronizations are available (and they clearly are).

xox said:
There is a very large spectrum of tests on OWLS anisotropy, here is a very small sample. I can provide you with many more tests of OWLS anisotropy.

Did you read the opening paragraph of the relevant subsection in that link?
 
  • #10
WannabeNewton said:
.
Did you read the opening paragraph of the relevant subsection in that link?

Yes, I am very familiar with the opening paragraph, I know Tom Roberts personally and I pointed out to him, repeatedly, that the way he wrote it it conveys the wrong message. But he is stubborn and he would not change it.
Your objection does not change the fact that there is a large spectrum of OWLS anisotropy tests. Most (if not all) experimentalists would disagree with your statement:

WannabeNewton said:
There is no experiment that can show the one-way speed of light is isotropic in inertial frames.

The test theories that Tom Roberts is talking about are exactly the instruments used to constrain light speed anisotropy. This is a much better way of explaining things than the negative way Tom Roberts wrote it.
 
  • #11
WannabeNewton said:
Elementary treatments tend to stick to 1-dimensional expositions however the same thing you do for 1-dimension applies to 3-dimensions except now you have to treat 3 independent directions as opposed to just 1.


I understand the basic premise of your post, but could you please give some additional details when comparing 1-dimensional analysis as opposed to 3-dimensional sync situation?
 

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