Is relativity of simultaneity measurable?

Suffice to say, that unlike you, Fednis48 understood that he's taken a mortal blow, in karate terms, and that the paper proves his fringe claim wrong. This is why he left the thread. What the paper demonstrates, is obvious to anyone knowing physics: a real experiment , constraining OWLS anisotropy. I do not expect you to be in the same category, of people understanding the paper, so, in classical RealityCheck style, you will troll to no end because this is all you do.

Lest anyone misunderstand, I didn't leave the thread because you made your case. I left the thread because you ignored my question six posts in a row. I sent a PM to Pete requesting moderation; until he gets back to me on that, I just don't see any value in responding to you anymore.
 
Lest anyone misunderstand, I didn't leave the thread because you made your case. I left the thread because you ignored my question six posts in a row. I sent a PM to Pete requesting moderation; until he gets back to me on that, I just don't see any value in responding to you anymore.

The answer is pretty simple:

1. You made an inference that is easily provable to be false given the very large number of tests that constrain OWLS anisotropy.
2. The Minguzzi "paper" is an embarrassment (for Minguzzi). If you go to the reference section, he lists no experiments, showing that he's totally ignorant (like you) on the fact that , at the time when he wrote the paper, there were already many experiments that falsified his theory. It is embarrassing to publish a theory that is already falsified by experiment. It is embarrassing to make claims, that are already falsified by existent experiments, Fednis. Look at the previous post, all the tests prior to 2001 (when he published his paper) falsify his claim.
I count 11 such papers that falsify Minguzzi's claim(there are more).
I can count 17 papers that falsify your fringe claim. So, why do you persist?
 
Undefined,

You cannot "concede" because you can never understand what this experiment is all about and because you make your living trolling websites.
Now the experiment constrains OWLS anisotropy via an experiment based on Compton scattering. The measurements have been taken at the GRAAL facility and the experimental data has been fitted in order to be compared against a parametrization in $$\zeta, \lambda$$ of the one way light speed $$c_{\gamma i}$$. This process resulted into placing constraints of the order of $$10^{-13}$$ for $$\zeta$$ and $$10^{-14}$$ for $$\lambda$$. To make the blow even harder, the paper lists a plethora of other papers constraining OWLS anisotropy. Here are a few (not all):

[2] V. G. Gurzadyan et al., Mod. Phys. Lett. A 20, 19 (2005).
[3] V. G. Gurzadyan et al., Il Nuovo Cimento B 122, 515(2007).
[4] V. G. Gurzadyan et al., arXiv:1004.2867, 2010.
[14] E. Riis et al., Phys. Rev. Lett. 60, 81 (1988).
[15] Z. Bay, J. A. White, Phys. Rev. Lett. 62, 841 (1989).
[16] T. P. Krisher et al., Phys. Rev. D 42, 731 (1990)

Here are some more:

Cialdea, Lett. Nuovo Cimento 4 (1972), pg 821.
Champeny et al., Phys. Lett. 7 (1963), pg 241.
Champeney, Isaak and Khan, Proc. Physical Soc. 85, pg 583 (1965).
Isaak et al., Phys. Bull. 21 (1970), pg 255.
Turner and Hill, Phys. Rev. 134 (1964), B252.
Gagnon, Torr, Kolen, and Chang, Phys. Rev. A38 no. 4 (1988), pg 1767.
T.W. Cole, Mon. Not. R. Astr. Soc. (1976), 175 93P-96P.
Ragulsky, Phys. Lett. A, 235 (1997), pg 125.

I already read about where the data came from which the researchers in your referenced paper were interpreting according to their own theoretical construct involving an "absolute" frame and anisotropy results according to azimuthal orientations. The fact that the anisotropy was indicated by the original data is obvious. The fact that the researchers in your referenced paper use that data and interpret it in their theoretical modeling using an absolute frame is not actually supporting your claims so far in any way. Merely constraining according to some theory involving anisotropy within an absolute frame is all that it says there. How does that exactly and unambiguously "support" your claims?

By the way, did you read lately where there is a movement afoot by professional scientists to have the "citation frequency" as a measure of "reliability" removed from the citation system altogether? Is that what you have been doing? Citing papers left and right without any regard to their validity to your claims?
 
I already read about where the data came from which the researchers in your referenced paper were interpreting according to their own theoretical construct involving an "absolute" frame and anisotropy results according to azimuthal orientations. The fact that the anisotropy was indicated by the original data is obvious. The fact that the researchers in your referenced paper use that data and interpret it in their theoretical modeling using an absolute frame is not actually supporting your claims so far in any way. Merely constraining according to some theory involving anisotropy within an absolute frame is all that it says there. How does that exactly and unambiguously "support" your claims?

RealityCheck

You did exactly what I predicted you will do: understand nothing and keep on trolling.
Interestingly enough, Fednis48 came back, so he had to absorb more data. Will he continue to embarrass himself? Will he concede like a real scientist would do? The jury is out.
 
Undefined

You did exactly what I predicted you will do: understand nothing and keep on trolling.
Interestingly enough, Fednis48 came back, so he had to absorb more data. Will he continue to embarrass himself? Will he concede like a real scientist would do? The jury is out.

Have you exactly and unambiguously shown where that paper supports your claims? Show please. Exactly and unambiguously without nebulous personal comments about others which you cannot demonstrate.
 

Please show exactly and unambiguously where in that paper it supports your claim.

Edit/: You have now linked back to your earlier post where you say:
the experimental data has been fitted

Can you explain exactly and unambiguously what this process of "fitting" entails in the context of your referenced paper/exercise based on "absolute" frame assumptions and theoretical modeling of the anisotropy data?
 
Tach is taking a break. No gloating. I've been too busy to keep up with this thread, which seems to have developed a few sidetracks.
Fednis, Undefined, OnlyMe, would you like to summarise the current state of affairs?
 
I did get a look at, at least a summary paper for the GRAAL experiment. A NEW LIMIT ON THE LIGHT SPEED ISOTROPY FROM THE GRAAL EXPERIMENT AT ESRF, (2010) The actual data for the experiment apears to be spread out over several papers, referenced by this paper. I have not looked at any of that data.

THIS IS NOT AN IN DEPTH ANALYSIS OF THIS PAPER. THAT WOULD REQUIRE SOMEONE WITH A GREAT DEAL MORE EXPERIENCE AND KNOWLEDGE OF THE METHODS, MECHANISMS AND PARTICLE PHYSICS, THAN I... And probably more time than I spent reading through the paper. With that caveat, my impressions are as follows...

The experiment does not measure the one-way speed of light. (Tach never claimed that.) It compares the one-way speed of photons, over time and direction and does not find the comparrison to be isotropic. The experimental data as interpreted, represents a null result, as it was intended as a test of SR which assumes that the one-way speed of light is isotropic and the experiment does include Lorentz transformations (another component of SR).

Even though they are working with a one-way light experiment, I would place this in the same catagory as a M&M class of experiment, where the speed of light over different paths is being compared. One-way speed in this case... The paths in this experiment being subject to the Earth's motion, including rotation, orbit ect.., all ultimately assuming the CMB, as a frame dependent isotropic background. This paper notes an anistrophy in one-way speed of light over the course of the experiment, but makes no assertion as to the cause... And does note that further study is required, followed by, "... clearly shows that there is no evidence of the 24 hours cycle that one would expect from the rotation of the Earth." Saying in essence, they did not get the results they expected, while they did so with better precission than earlier tests.

I did not spend a great deal of time on this paper and did not look deeper into the data it refers to in the additional papers. That said from what I see here, after accounting for the expected Lorentz transformations, which should have returned a variation in the one-way speed of light relative to the 24 hour rotation of the earth, they found no associated variation, their results were isotropic after Lorentz transforms were accounted for, and thus the experiment returns a null result. (Keep in mind that the Lorentz transforms, applied after the fact , were an explanation for the null results of the two-way M&M class experiments.) Transforms applied in advance of data analysis in this case should have returned a variation...

Since this experiment was fixed relative to the earth and all rotation was relative to the Earth's motion, compared to the CMB preferred frame, they were not comparring the velocity of light between the two legs of a two-way light path... So the results have limited application to the relationship between OWLS and TWLS, other than the experiments comparing the two, relative to direction of propagation both return similar results. This should be expected. If the results had been different than the two-way experiments, that would have been big news. As it stands they appear to be consistent with the two-way experimental results, with the exception of variations in the accuracy of isotropic or anisotropic limits, depending on the experimental design.

It would be interesting to see the results of this type of experiment where two accelerators operating in opposite directions were run at the same time. That would come close to a comparrison of two legs of a two-way light path.


One further note, the only reference in this paper to an absolute frame is in the introduction or abstract statement. In the paper itself the CMB frame is referred to as an isotropic rest frame (for the experiment). The authors do not apear to me to be declaring the CMB to represent any universal or absolute rest frame.
 
Tach is taking a break. No gloating. I've been too busy to keep up with this thread, which seems to have developed a few sidetracks.
Fednis, Undefined, OnlyMe, would you like to summarise the current state of affairs?

Pretty much everyone seems to have agreed that relativity of simultaneity (RoS) is not technically measurable, because to measure simultaneity one needs a clock synchronization scheme. For reasons explained in the links in post 95, clock synch schemes are inherently untestable, so RoS is also untestable by extension.

The debate is still going on about whether the one-way speed of light (OWLS) can be measured experimentally. I think I speak for everyone in the thread except Tach when I say that the links in post 95 all seem to indicate that the isotropy of OWLS is equivalient to the validity of Einstein clock synchronization (E-synch), so if E-synch is untestable, it follows that the isotropy of OWLS (or at least, the absence of certain classes of OWLS anisotropy) must be untestable as well. Tach has been arguing against this by citing a frankly jaw-dropping number of papers which he claims measure the isotropy of OWLS.
 
Pretty much everyone seems to have agreed that relativity of simultaneity (RoS) is not technically measurable, because to measure simultaneity one needs a clock synchronization scheme. For reasons explained in the links in post 95, clock synch schemes are inherently untestable, so RoS is also untestable by extension.

I believe there are three primary issues involved in this.
  1. Clearly defining the experimental analog to be tested.
  2. Determining which measurements are required to prove RoS.
  3. Establishing whether the measurements need to be absolute or to an experimental accuracy that will result in useable data.

If all that is needed are measurements whose accuracy is sufficient to demonstrate RoS, most of an analog of Einstein's hypothetical should be able to be constructed within the context of today's available technology... Most but perhaps not all..

It would seem that if CERN can measure distances and times so as to measure the speed of neutrinos, to within nano seconds, it should be possible to establish simutaneous flashes with an equivalent or greater accuracy.., and measure those flashes to be simutaneous from a point equidistant from both flashes. This would establish a rest frame for experimentally simultaneous flashes.

It should also be possible to both time the flashes so they occur as a moving detector passes the stationary detector, and then compare the order in which the two detectors measured the flashes occurring....

The problem is in making the measurements of the distances in the moving frame between where the flashes occurred and the mid point in that frame. This would have to be done with a system separate from the flashes. I am unsure that present technology could locate the ends of the moving frame with the same accuracy, as the stationary frame. GPS gets to within what feet(?), for moving targets..?

The question then becomes is the distance measurement in the train frame important to the measurement of Simutaneity?.. And would the difference in the measurements made in the two frames be greater than the systemic error and accuracy of both the time and distance measurements required?

Only as an exagerated example... If it were determined that the measurement accuracy were to within say a few billionths of a second and the difference between the time intervals of the flashes (compared between frames) were greater than that margin, the test should confirm if not prove to a certainty RoS.

An additional problem that comes into play is that the moving frame is length contracted. That length contraction may function in this case in a similar way as in M&M case TWLS experiments.., the experiment would return essentially null results... If the length in the moving frame is important.

From how I look at it the moving frame length should not be an issue if the flashes can be established to be simultaneous in the rest frame to within the limits of measurement... And once again the comparrison of the timing of the flashes as measured in both frames differes by more than the limits of measurement.

The debate is still going on about whether the one-way speed of light (OWLS) can be measured experimentally. I think I speak for everyone in the thread except Tach when I say that the links in post 95 all seem to indicate that the isotropy of OWLS is equivalient to the validity of Einstein clock synchronization (E-synch), so if E-synch is untestable, it follows that the isotropy of OWLS (or at least, the absence of certain classes of OWLS anisotropy) must be untestable as well. Tach has been arguing against this by citing a frankly jaw-dropping number of papers which he claims measure the isotropy of OWLS.

Part of this I think is backwards. E-synch is based on the assumption that OWLS = TWLS, as a fundamental component of SR. So if OWLS is measureable E-synch should be testable. If it is not measureable E-synch would not be testable.
 
Pretty much everyone seems to have agreed that relativity of simultaneity (RoS) is not technically measurable, because to measure simultaneity one needs a clock synchronization scheme. For reasons explained in the links in post 95, clock synch schemes are inherently untestable, so RoS is also untestable by extension.

If we begin with the postulates of SR, then RoS is just as measurable as length contraction. I don't know where this idea came from that we cannot accept the postulates of SR at face value. In his seminal 1905 paper, Einstein wrote, "We have not defined a common 'time' for A and B, for the latter cannot be defined at all unless we establish by definition that the 'time' required by light to travel from A to B equals the 'time' it requires to travel from B to A."

And in his 1920 book he wrote, "I maintain my previous definition nevertheless, because in reality it assumes absolutely nothing about light. There is only one demand to be made of the definition of simultaneity, namely, that in every real case it must supply us with an empirical decision as to whether or not the conception that has to be defined is fulfilled. That my definition satisfies this demand is indisputable. That light requires the same time to traverse the path A —> M as for the path B —> M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity."
 
If we begin with the postulates of SR, then RoS is just as measurable as length contraction. I don't know where this idea came from that we cannot accept the postulates of SR at face value. In his seminal 1905 paper, Einstein wrote, "We have not defined a common 'time' for A and B, for the latter cannot be defined at all unless we establish by definition that the 'time' required by light to travel from A to B equals the 'time' it requires to travel from B to A."

And in his 1920 book he wrote, "I maintain my previous definition nevertheless, because in reality it assumes absolutely nothing about light. There is only one demand to be made of the definition of simultaneity, namely, that in every real case it must supply us with an empirical decision as to whether or not the conception that has to be defined is fulfilled. That my definition satisfies this demand is indisputable. That light requires the same time to traverse the path A —> M as for the path B —> M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity."

I don't think anyone including Tach questions the validity of RoS or that OWLS = TWLS, as assumptions of SR. The discussion was about whether there was any way to test and/or prove them, and what the difficulties might be.

A few of Tach's references were tests of OWLS isotrophy, but all fell into the M&M class of experiments (this could be debatable in itself) or similar, where their result were inconclusive on that issue. They all returned anisotropic results, with increasing accuracies. A few seem to have jumped on that as a violation of Lorentz invariance.

None of this really amounted to science, other than as an exploration of ideas. If ether RoS or the OWLS could be measured experimentally, I am sure some one would have. It was just a bunch of people outside the beltway, so to speak, exploring the possibilities.., and things got a little too antagonistic.
 
If ether RoS or the OWLS could be measured experimentally, I am sure some one would have.

There are wholes schools of thought that say that OWLS is not measurable. But the postulates of Special Relativity ensure that RoS would be measurable when using E-Synched clocks.
 
There are wholes schools of thought that say that OWLS is not measurable. But the postulates of Special Relativity ensure that RoS would be measurable when using E-Synched clocks.

This is true.

What I was getting at is that E-synch does not precede the assumption of an isotropic one-way speed of light in SR. It actually depends on that assumption.

If the one-way speed of light were not isotropic, then E-sync would not work. The synchronization between two clocks would differ depending on from which clock the light signal originated. Light would move faster between the two clocks in one direction...

E-synch depends upon the assumption that one-way light speed is isotropic, or equal to the two-way speed, in an inertial frame of reference.
___________

At present I don't think there is any way to experimentally measure the one-way speed of light, with the same kind of accuracy that the two-way speed is measured. This is largely due to the fact that it requires synchronized clocks and all methods of synchronization we have, depend to some extent on the assumption that either the one-way speed of light is isotropic or that in the case of slow transport length contraction and time dilation due to relative velocity can be ignored... Which only suggests that any variation is outside our ability to measure it... And it depends on both clocks remaining in a uniformly flat spacetime.., or equivalent locations within any relevant gravitational field.
___________

RoS is a different issue. If what you are striving for is absolute accuracy in all measurements, then it is not possible to measure two separated events to be simutaneous, with certainty. Every experimental construction I have heard of or can think of requires some initial and fundamental assumptions. Those assumptions limit the certainty, to the extent that "they" are assumed rather than proven.

However, it can be experimentally proven that spacially or inertially separated observer's will measure events to occur in different orders, which is the more general underlying intent of RoS. This can be done without knowing that the two events are in fact simutaneous in a frame common to both events. It need only be observed to be simutaneous by one observer and sequential by the other. If we use flashes of light we are then essentially comparing the proper time of each observer's detection of the flashes, rather than when they (the flashes) originated. There is debate as to whether this would be a test of RoS even though it is the result of the same underlying "mechanics".
 
What I was getting at is that E-synch does not precede the assumption of an isotropic one-way speed of light in SR. It actually depends on that assumption.

If the one-way speed of light were not isotropic, then E-sync would not work. The synchronization between two clocks would differ depending on from which clock the light signal originated. Light would move faster between the two clocks in one direction...

E-synch depends upon the assumption that one-way light speed is isotropic, or equal to the two-way speed, in an inertial frame of reference.

E-synch "works" whether the one-way speed of light is isotropic or not. Once two clocks are E-synched, they will measure the one-way speed of light to be the same in both directions between them. Did you read the quotes I provided from Einstein? He knew as far back as 1905 that he was defining simultaneity by stipulating that the one-way speed of light would be considered to be isotropic in his theory. Please read this:

Neddy Bate" said:
In his seminal 1905 paper, Einstein wrote, "We have not defined a common 'time' for A and B, for the latter cannot be defined at all unless we establish by definition that the 'time' required by light to travel from A to B equals the 'time' it requires to travel from B to A."

And in his 1920 book he wrote, "I maintain my previous definition nevertheless, because in reality it assumes absolutely nothing about light. There is only one demand to be made of the definition of simultaneity, namely, that in every real case it must supply us with an empirical decision as to whether or not the conception that has to be defined is fulfilled. That my definition satisfies this demand is indisputable. That light requires the same time to traverse the path A —> M as for the path B —> M is in reality neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which I can make of my own freewill in order to arrive at a definition of simultaneity."

He says that isotropy of the one-way speed of light is neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which he makes of his own freewill in order to define simultaneity.


RoS is a different issue. If what you are striving for is absolute accuracy in all measurements, then it is not possible to measure two separated events to be simutaneous, with certainty. Every experimental construction I have heard of or can think of requires some initial and fundamental assumptions. Those assumptions limit the certainty, to the extent that "they" are assumed rather than proven.

We don't have to prove the one-way speed of light to be isotropic. On the other hand, if we had proof that it was not isotropic, then that would be something we'd probably want to take into consideration.


However, it can be experimentally proven that spacially or inertially separated observer's will measure events to occur in different orders, which is the more general underlying intent of RoS. This can be done without knowing that the two events are in fact simutaneous in a frame common to both events. It need only be observed to be simutaneous by one observer and sequential by the other. If we use flashes of light we are then essentially comparing the proper time of each observer's detection of the flashes, rather than when they (the flashes) originated. There is debate as to whether this would be a test of RoS even though it is the result of the same underlying "mechanics".

If your observers are both located at the midpoint between the two events, (as they are in Einstein's thought experiment), then what you have written is exactly RoS, not just "the more general underlying intent of RoS". On the other hand, if your observers are not both located at the midpoint between the two events, then what you have written is not RoS at all.
 
E-synch "works" whether the one-way speed of light is isotropic or not. Once two clocks are E-synched, they will measure the one-way speed of light to be the same in both directions between them. Did you read the quotes I provided from Einstein? He knew as far back as 1905 that he was defining simultaneity by stipulating that the one-way speed of light would be considered to be isotropic in his theory. Please read this:

This was my point exactly. Einstein based his synchronization on the stipulation or assumption that the one-way speed of light was a constant or isotropic. We accept that only as an assumption, of SR.


He says that isotropy of the one-way speed of light is neither a supposition nor a hypothesis about the physical nature of light, but a stipulation which he makes of his own freewill in order to define simultaneity.

Again a stipulation, is made without proof. One-way speed of light had not at that time, nor at any time since been measured. It is one of the assumptions that SR is based on which has as yet to be verified experimentally.

We don't have to prove the one-way speed of light to be isotropic. On the other hand, if we had proof that it was not isotropic, then that would be something we'd probably want to take into consideration.

Either case would require a measurement of the one-way speed of light, on both legs of a two-way light path. To date there has been no measurement of any one-way speed of light, in vacuum. What has been done is a comparrison of one-way light paths, separated by both orientation and time. None of these tests of one-way isotrophy, have included both legs of a two way light path.

If your observers are both located at the midpoint between the two events, (as they are in Einstein's thought experiment), then what you have written is exactly RoS, not just "the more general underlying intent of RoS". On the other hand, if your observers are not both located at the midpoint between the two events, then what you have written is not RoS at all.

In Einstein's hypothetical the two observers are located at the midpoint only at the instant that the lightning strikes occur. They are not both at the midpoint when they detect and measure the resulting flashes. It is that difference in their measurement of when the flashes occurred that is key, as I see the underlying intent. It is just gravy, so to speak, that Einstein, constructed the hypothetical such that the lightning strikes were simultaneous in both frames, but the flashes were observed to be simultaneous only in the embankment frame.

My contention has been that the order that the flashes are observed and recorded is more important than the actual simultaneity of the lightening strikes. Why? Later in the developement of SR it become apparent that no observer can in fact determine remote events to be simultaneous, other than as they are observed and recorded from the remote frame, which does not represent measurements of proper time or even at times proper locations... We can know if the flashes are simultaneous, but not the actual events that produce the flashes... Not in practice, or so far in any experiment.

RoS is really about what is observed to be simultaneous by one observer is not observed to be simultaneous by all observers. This does not require absolute knowledge that any two events are in fact simultaneous in their common frame of reference.
 
This was my point exactly.

You had said E-synch does not work without isotropic OWLS. My point was that it does.


In Einstein's hypothetical the two observers are located at the midpoint only at the instant that the lightning strikes occur. They are not both at the midpoint when they detect and measure the resulting flashes. It is that difference in their measurement of when the flashes occurred that is key, as I see the underlying intent.

In the embankment frame, observer M is always located at the midpoint between the events.

In the train frame, observer M' is always located at the midpoint between the events.


It is just gravy, so to speak, that Einstein, constructed the hypothetical such that the lightning strikes were simultaneous in both frames, but the flashes were observed to be simultaneous only in the embankment frame.

No, the hypothetical was constructed so that the lightning strikes were only simultaneous in the embankment frame. There is no reason whatsoever to think they were simultaneous in the train frame.
 
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