Age of Universe relative to what?

  • #51
my_wan said:
It is also possible to measure the one way speed of light, though I know of no explicit examples of it actually being done. Simply take a rotating hollow disk with holes on opposite side and note the RPM ranges in which a very short flash of light makes it through the disk to be detected, or some variation thereof.
So you think a mechanical device can instantly transmit time information over a long distance? Sorry, that won't work.
 
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  • #52
my_wan said:
It is also possible to measure the one way speed of light, though I know of no explicit examples of it actually being done. Simply take a rotating hollow disk with holes on opposite side and note the RPM ranges in which a very short flash of light makes it through the disk to be detected, or some variation thereof.
This seems similar to yuiop's proposal discussed in detail here:
https://www.physicsforums.com/showthread.php?t=461274
 
  • #53
ghwellsjr said:
So you think a mechanical device can instantly transmit time information over a long distance? Sorry, that won't work.

The device doesn't need to transmit time information. The distance between the two holes determine the timing, not clocks. The only variable involving a clock is the RPM of the disk. Are you saying I can't know the RMP of the disk over long distances? Even setups that have the light source on full time can work and the only thing measured is RPM and what RPM ranges did the light get through.

I can think of a few more approaches using a CCD, since you can actually tell where on a CCD the light hit and even position shifts of a frequency variance over the CCD. Creating a light source with a frequency spread like this is easy enough.

Never really cared much but I'll look over the links.
 
  • #54
ghwellsjr said:
So you think a mechanical device can instantly transmit time information over a long distance? Sorry, that won't work.
We can always use subspace transmission to send a message really fast! ;)
 
  • #55
I see that thread still involved clocking flashes. There is no need. You have a rotating hollow pipe of a given length with an always on light source at one end, such that when the pipe points at the light source it goes through the pipe and detected at the other end. If the RPM is large enough the light never makes it through the pipe to be detected. The RPM is the only effective clock.
 
  • #56
It wouldn't even have to be a binary result, such that light was either detected or not. Since as the RPM increased the effective size of the hole is reduced which reduces the intensity of light as a result of a finite C. Neither would the relativity of rigidity play a role, since we know the the end results are always the same as if we presumed the relativity of rigidity played no role.

So here we have variation in both intensity and duration, where duration is not too significant in terms of the speed C, mostly just the effect of RPM alone, but intensity is. This would allow measurements with a finer grained variation in RPM and testable over a greater range of RPM.
 
  • #57
Could you explain your experiment in more detail? I can't figure out what you are proposing. You started with a "rotating hollow disk with holes on opposite side" and now you're talking about a "rotating hollow pipe". Please describe the orientation of these rotating devices and where the holes are and how the light propagates, etc. I'm sure it's clear in your mind but it's not in mine.
 
  • #58
my_wan said:
I see that thread still involved clocking flashes. There is no need. You have a rotating hollow pipe of a given length with an always on light source at one end, such that when the pipe points at the light source it goes through the pipe and detected at the other end. If the RPM is large enough the light never makes it through the pipe to be detected. The RPM is the only effective clock.
The key objection, which applies to your idea, is this one:
https://www.physicsforums.com/showpost.php?p=3069207&postcount=14
with some follow-up here:
https://www.physicsforums.com/showpost.php?p=3070985&postcount=21
and here:
https://www.physicsforums.com/showpost.php?p=3075250&postcount=33

Your device let's through light at a specific speed due to its geometry. However, in theories with non-isotropic 1-way speeds of light (i.e. non-Einstein synchronization conventions) the length contraction is no longer isotropic and the device is geometrically distorted such that the light passes.

You simply cannot measure the one-way speed of light without assuming it.
 
  • #59
In the configuration it really makes no difference whether the pair of holes the light must pass through is a pair of holes on a surface of a cylinder or a hollow pipe in which the light must pass.

DaleSpam brings up a bigger issue. In the context of standard relativity the relativity of rigidity, as I've noted, makes no difference to the outcome. If "theories with non-isotropic 1-way speeds of light" are merely a different choice of synchronization then this is in principle perfectly allowed by relativity. Relativity only chose the synchronization procedure to match the maximal rate at which a given observer could obtain information about global coordinates as it was mathematically expedient, and only restricted it in such a way that effects could not precede causes. Choosing a different synchronization procedure in principle is no more physically significant than selecting a different coordinate choice. Trying to attach 'real' physical meaning to that is no different that arguing over which clock is really going slower, or which of two meteors the relational kinetic energy is 'really' located at.

Therefore, simple choosing a differing synchronization procedure which gives differing mathematical conditionals of space and time, has no physical meaning. Trying to require it to be measurable is like trying to measure the difference between 1 inch and 2.54 cm.

If the actual physics differs, outside of what is effectively a coordinate choice, then the anisotropy measuring procedure stands. That's why I mentioned my lack of real interest, because the only reasonable anisotropic C theories I seen are nothing more than an effectively different coordinate choice. Which might still provide some interesting numerical solutions to difficult problems and/or interesting perspectives.

We already know from GR that light speed does not constitute an absolute constant, only a relational constant.

The only people a measurable anisotropic C has any bearing on is the Einstein is wrong crowd. The people looking for some kind of absolute coordinate choice as if it is a physically real thing.
 
  • #60
ghwellsjr said:
Could you explain your experiment in more detail? I can't figure out what you are proposing. You started with a "rotating hollow disk with holes on opposite side" and now you're talking about a "rotating hollow pipe". Please describe the orientation of these rotating devices and where the holes are and how the light propagates, etc. I'm sure it's clear in your mind but it's not in mine.

my_wan said:
In the configuration it really makes no difference whether the pair of holes the light must pass through is a pair of holes on a surface of a cylinder or a hollow pipe in which the light must pass.

If you are going to claim that your method of measuring the one-way speed of light works, then you must have a way of measuring how long it takes for light to traverse some measured distance. Just saying that you have a rotating object with holes in it does not communicate what you have in mind.

If you have lost interest in defending your claim, I would at least urge you to read the wikipedia article on "one-way speed of light" to see that several attempts at measuring it have proved to be failures.
 
  • #61
ghwellsjr said:
If you are going to claim that your method of measuring the one-way speed of light works, then you must have a way of measuring how long it takes for light to traverse some measured distance. Just saying that you have a rotating object with holes in it does not communicate what you have in mind.

If you have lost interest in defending your claim, I would at least urge you to read the wikipedia article on "one-way speed of light" to see that several attempts at measuring it have proved to be failures.

My lack of interest only extends to my personal desire to developing such proposals. Answering the questions here is not an issue.

I'll try to outline it more clearly, using the pipe version. It is very similar to what yuiop suggested here, but does not require flashing a light. The light can be on full time. Whether it makes it to the detector, and how much, is what is measured. I also reiterate why the Relativity of Simultaneity (RoS) is not and issue, as brought up in the previous thread, and how it is timed.

Consider a radial arm of length r with a 1 cm square hole down the length of it. At one end there is a 1 cm^2 CCD used to detect the light intensity. The only way for light to get to this CCD is through the hole down the full length of the pipe. This pipe is then given an axis of rotation at r/2, with the open end of the pipe passing the light source. Hence at any given non-zero RPM the light only has a certain amount of time to get to the CCD before before it hits the pipe rotating into its line of travel. Knowing the RPM is the only clocked variable needed. If the pipe is 1 m long then the light must travel 1 meter minimum before the end of the rotating pipe moves 1 cm. If the photons is less than optimally aligned with the hole at entry it will have to move even faster to get to the detector.

1) The only clock is the RPM and length of the pipe.
2) The light is on constantly.
3) If the open end of the pipe travels at least 1 cm (defined by pipe length and RPM) before the light travels r then no light will ever make it to the detector.
4) No other clocks or timing mechanisms needed other than 1), such that no synchronization is required.
Synchronization is provided as a function of geometry, so I'll deal with the RoS issues again.

RoS:
SR clearly predicts that the experimental results of any effects of RoS exactly matches the experimental results to be expected if you never bothered with the mathematics of RoS to begin with. Hence expected results per SR need not mathematically bother with the rigidity issue in SR. Such issues are only relevant to appearances from differing frames, all of which agree on what end results both should be and are if SR holds. It's a waste of time to bring it up, unless some other theory attaches some real physical and differing meaning to this rigidity issue beyond a simple coordinate choice.

Measuring Results:
At 0 RPM with the open end of the pipe facing the light source you will get a maximal light intensity on the detector. Even a small RPM will prevent some minute percentage of the photons from reaching the detector, lowering the light intensity. Note that the time interval in which light reaches the detector is not what we are trying to measure, only the change in average intensity at a given instant. Though it is perfectly fine to average over the intensity for each rotation, if you curve fit against the expected drop in average intensity resulting from reduced duration with increased RPM.

What we are then looking for is a deficit in light intensity, compared to the expectation curve if the speed of light was assumed infinite. Tracking this over a large range of RPMs then let's us compare not only the expectation of single points, but track the expectations curves over a large range of expected curves. This allows us to remove a large amount of noise in the data, much like with an interferometer can obtain a partial wavelength resolution.

Results:
If an alternative physical interpretation involves a differing relative ratio between geometry and clocks, such that they covary in different ways, then this setup should measure if if it is within range of the resolution provided by the setup. If the covariance between clock and geometry does not differ then the alternative model is only arguing about a non-physical coordinate choice rather than any physically meaningful effect. This is because the only clock in operation here is the RPM requiring the geometry predicted by SR to be meaningful in relation to that RPM clock. Hence this only synchronizes a clock with geometry, not any other clock. In SR and GR geometry is a type of clock, and a clock is a type of geometry in which any physically differing theory must disagree on how they covary in some way.
 
  • #62
I'm sorry but I still have trouble with what you are describing. Let me ask some questions and if you already answered them, then please quote where you did:

1) Is the CCD fixed to the end of the pipe and rotating with it?

2) Is the light source not spinning with the pipe?

3) Is the pipe spun at its center like a two-bladed propeller?

If you answer all the questions with "yes", then how does any light get down through the pipe when it is spinning at a high speed? It seems like the CCD will only pick up light when the pipe is stopped and aligned with the light source and as soon as you start accelerating it, the light will immediately drop off and never be detected again. I can't see any RPM that would let the light travel down the pipe. What am I missing?
 
  • #63
ghwellsjr said:
I'm sorry but I still have trouble with what you are describing. Let me ask some questions and if you already answered them, then please quote where you did:

1) Is the CCD fixed to the end of the pipe and rotating with it?

2) Is the light source not spinning with the pipe?

3) Is the pipe spun at its center like a two-bladed propeller?

1) Ideally yes, but so long as the light only reaches it through the pipe hole it makes no difference.

2) No. It is fixed with the pipe hole pointing directly at it once per revolution.

3) Yes, that is best for balance and maximal length for the torque involved.

ghwellsjr said:
If you answer all the questions with "yes", then how does any light get down through the pipe when it is spinning at a high speed? It seems like the CCD will only pick up light when the pipe is stopped and aligned with the light source and as soon as you start accelerating it, the light will immediately drop off and never be detected again. I can't see any RPM that would let the light travel down the pipe. What am I missing?
So are you saying 1 revolution per hour is enough to stop light from getting through?

The more sensitive the light intensity (not duration) variation is to RPM the better. Yet it's not binary where just any speed will completely shut off the light getting through during the time the hole faces the light source. The light has to be slow enough that it falls to get to the detector before the pipe rotates into it, such that the photons collide with the walls inside the hole. If the expected light duration drops too fast to provide enough detection simply increasing the intensity of the light source is sufficient. This is because it is not absolute intensities that are being measured. Rather it is the relative drop rate in the intensity curve above the expectations when C is assumed infinite that you are comparing the entire range of RPMs against.

If C was infinite then the curves exactly match. There would never be an intensity drop during that time, no matter how short, that the hole was aligned with the light source. The slower the finite speed the greater the deviation from the reference curve, and the more rapidly it deviates from this reference curve with higher RPM.

I'm not sure what the difficulty is in the description. CCD detectors can essentially detect down to single photons getting through. Obviously you want a more intense light source than that.
 
  • #64
my_wan,

DaleSpam has already suggested the flaw in this experiment in post #58. To calculate the speed of light from the measured radius and angular velocity, you need to compute the linear velocity of both ends of the rod, relative to an inertial frame in which the centre of rotation is at rest.

If you assume Einstein synchronization, this is easy enough, and the two velocities are equal and opposite. But with some other synchronization, the two velocities need not be equal in magnitude, so you have insufficient information to calculate them without knowing the synchronization convention.

Your method implicitly assumes Einstein synchronization, i.e. that the one-way speed of light equals the two-way speed, so it is actually measuring the two-way speed.
 
  • #65
my_wan said:
In the context of standard relativity the relativity of rigidity, as I've noted, makes no difference to the outcome.
What is "the relativity of rigidity"? I have never heard of that.
 
  • #66
DaleSpam said:
What is "the relativity of rigidity"? I have never heard of that.
Basically Born rigidity as he was the first to introduce the notion. Though a lot of other cases have been added since, such as Rindler's rod and hole paradox [Am. J. Phys. 29 365–6 (1961)], the pole and barn or ladder and barn paradox, etc. Basically anything that involves the Herglotz-Noether theorem [J. Math. Phys. 8, 919 (1967)]. Recently Ziyang Hu offered a proof of Herglotz-Noether theorem in all dimensions in a preprint: http://arxiv.org/abs/1004.1935

DrGreg said:
my_wan,

DaleSpam has already suggested the flaw in this experiment in post #58. To calculate the speed of light from the measured radius and angular velocity, you need to compute the linear velocity of both ends of the rod, relative to an inertial frame in which the centre of rotation is at rest.
These I have responded to. In effect my solution was to simply accept the Herglotz-Noether theorem. I'll reiterate below, but you can also put the detector at the center of the pipe for the same general measurement. If differing linear velocities was physically meaningful beyond what the Herglotz-Noether theorem entails then the results will differ from an expectation curve. That's why instead of data points from a singular linear velocity giving a speed C, we also want a continuous range of RPMs to compare the variations over.


DrGreg said:
If you assume Einstein synchronization, this is easy enough, and the two velocities are equal and opposite. But with some other synchronization, the two velocities need not be equal in magnitude, so you have insufficient information to calculate them without knowing the synchronization convention.

Naturally I take the Einstein synchronization to compute the expectation curve. When you speak of "equal in magnitude" in the manner suggested then you must implicitly attach some form of absolute meaning to a magnitude for this to be relevant. This implied absolute magnitude includes both space and time such that absolute simultaneity is implied. If not then relativity does not preclude, nor deny the validity of, alternative synchronization methods which provide differing magnitudes of time and distance so long as the consequences are the same. In this respect differing synchronization procedures are effectively no different than a non-physical coordinate choice.

Hence the only real question is how do such differing models differ physically, beyond what is effectively a coordinate choice. If they do then you can get effects like Bell's spaceship paradox where they shouldn't be. Anything less and relativity makes no claims of it being wrong, in which case the only question is of what mathematical value is it for solving certain problems.

DrGreg said:
Your method implicitly assumes Einstein synchronization, i.e. that the one-way speed of light equals the two-way speed, so it is actually measuring the two-way speed.
In effect what you are saying is that if relational quantities do not differ, but theory X wants to attach an absolute value in some degree to one of the relational variables in a manner that doesn't contradict relational values then this is somehow a physically differing theory? I did not assume Einstein synchronization was uniquely valid. I do not assume that relativity claims that Einstein synchronization is uniquely valid. I only assume it is one of an unknown number of equally valid solutions. If you want a differing theory that is physically meaningful beyond what is effectively a coordinate choice either show the physical effects or explain which of two meteors with x relational (kinetic) energy the energy is located at.

If there is such a physical difference it will either show up as an isotropy in C at some RPM, the divergence in the curves as the RPM increases, or incongruence in the same curve fitting data over one or more linear velocities when the detector is placed at the center of the pipe. It's certainly possible to find some effect in the same way Bell's spaceship paradox results in a real effect when the spaceships use their respective Einstein synchronizations in an accelerated frame. Otherwise the whole point is of arguing the differing claim in the two models is effectively nothing more than a debate over which spaceships clock is really going slower.
 
  • #67
my_wan said:
1)So are you saying 1 revolution per hour is enough to stop light from getting through?
Yes, for about 59 minutes out of the hour.

I'm still not comprehending how RPM can determine the one way speed of light. It seems to me that if you spin the apparatus at some high RPM, no light will get through. If you slow it down, eventually some light will start to get through, but you said you want to maximize the intensity of the light, so as you continue to slow it down, more light will get through in bursts until finally the maximum light gets through at a very slow RPM and then if you continue spinning in the opposite direction, you will start minimizing the intensity. Don't you agree that the maximum intensity is when the pipe is stopped with the light shining through it? How can there be an increase in intensity beyond that point at any RPM?
 
  • #68
ghwellsjr said:
Yes, for about 59 minutes out of the hour.

I'm still not comprehending how RPM can determine the one way speed of light. It seems to me that if you spin the apparatus at some high RPM, no light will get through. If you slow it down, eventually some light will start to get through, but you said you want to maximize the intensity of the light, so as you continue to slow it down, more light will get through in bursts until finally the maximum light gets through at a very slow RPM and then if you continue spinning in the opposite direction, you will start minimizing the intensity. Don't you agree that the maximum intensity is when the pipe is stopped with the light shining through it? How can there be an increase in intensity beyond that point at any RPM?

And during that 1 minute the detectors receives x light which is x/60s light intensity. In this way intensity is expressed in terms of an intensity moment. Now you increase the RPM slightly such that some later data point only gives 30 seconds of light. Thus the intensity moment becomes x/30s. Now compare the theoretical curve that plots hundreds of data points at hundreds of RPM and compare it to experimental curves. In this way the absolute intensity of the light makes no difference so long as it is constant. However, if you want to assume this absolute intensity is physically meaningful, or that the transition across the pipe midpoint is somehow equivalent to a return path, plot similar data for small increments as the detector is moved increasing closer to the pipes midpoints.

In effect you can completely map all variables of the space relationally. If the relational variables are consistent then whatever model you choose that is consistent with it is fine. Relativity makes no claims of the validity, or lack of, concerning the physical status of such a model. Relativity only tells us about what the relational variables must be, not what physical model you can and cannot model these relational variables with.
 
  • #69
OK, well, I overlooked the fact that two times per revolution the light will be able to travel down the pipe but I still don't see how it can get through with more intensity than if the pipe were stopped with the pipe letting the light through.

And what's this about moving the detector closer to the pivot point? I must have a completely wrong idea about what you are talking about. Can you draw a picture?
 
  • #70
ghwellsjr said:
OK, well, I overlooked the fact that two times per revolution the light will be able to travel down the pipe but I still don't see how it can get through with more intensity than if the pipe were stopped with the pipe letting the light through.
The description I give did not include detecting the light twice per revolution, though I see no problem with including that scenario if it helps anything. I think you are having trouble with the notion of an intensity "moment" as opposed to variations in absolute intensity. So I'll describe it without the logic of "moments".

It does not get through with "more" intensity. If the speed of light is infinite then the total amount of light getting through on each revolution drops as the RPM increases. If the speed of light is finite the amount of light getting through on each revolution drops even faster. So the "more" is not an increases of intensity. It is merely more of a decrease than what you would get with an infinite light speed. How much more is determined by the actual speed of light.

The infinite light speed curve to be calculated is the reference curve saying how fast the total light detected per revolution should decrease. The experimental results, given a finite light speed, should be even less light getting through. We can now compare, not just two data points, but the entire RPM curve to factor out noise. Both curves are less (not more) light per revolution, but one curve is still more than the other curve. How much gives the speed of light.

ghwellsjr said:
And what's this about moving the detector closer to the pivot point? I must have a completely wrong idea about what you are talking about. Can you draw a picture?
I only added the movable detector to respond to criticisms, much like your issue with light being detected twice per revolution, which I don't see any effective difference. Yet both are perfectly valid variations of the same test. I can draw a picture but it still needs understood that "more" does not mean more light. More is only relative to how much more one value drops compared to another when both are decreases. The actual implementation details can vary without effectively changing the test.
 
  • #71
I want to respond to this again, and add two more objections:
DrGreg said:
Your method implicitly assumes Einstein synchronization, i.e. that the one-way speed of light equals the two-way speed, so it is actually measuring the two-way speed.
1) The usual reason given for the difficulty in measuring the one way light speed is the need for synchronizing a pair of clocks. So where is the implicit second clock in this setup? In fact the second clock is not a clock but a distance, and it is this relationship between clocks and distance that is in question. Hence to say the distance is an implicit clock requires assuming that a distance really is a valid clock, as per relativity, in order to claim a second clock. Yet if a distance does not covary with clocks as relativity dictates then this test will show it in the curve ratios. Hence I have not assumed Einstein synchronization.

2) Mathematically I am only assuming Newtonian synchronization and an infinite speed of light. Relativity alone doesn't require me to assume any more than this. Therefore, the assumption of Einstein synchronization is neither contained in the geometry or mathematics, nor is t=0 predefined for any pair of clocks.
 
  • #72
Quite some time back I dabbled with the idea of detecting a one-way c variation based on differential phase-shift in adjacent optical fibers (no clocks). Never pursued it though once the realization came what detecting an actual one-way c anisotropy, by any arrangement, implies: https://www.physicsforums.com/showpost.php?p=3080684&postcount=64 - see last paragraph. Physics would be (inertial) frame dependent - period. I hesitate to rule that out absolutely, but it does tend to make one think rather more carefully.
 
  • #73
Well now Q-reeus let the cat out of the bag. I was going to try to understand your setup, my_wan, but it really doesn't matter. Let's stipulate that your apparatus will work as you believe it will. Now the question is: will your apparatus ever be able to measure a one-way speed of light that differs from c?

For example, let's say that you use it to measure the light from the two stars in a binary star arrangement where one of them is known to be traveling toward you and the other one is traveling away from you. Don't you agree that any apparatus will measure an equal speed for both light beams, correct? And your apparatus will measure that speed to be c, correct? Now let's say that you are able to send one copy of your apparatus at a high speed toward the binary star and a second one at a high speed in the opposite direction away from the binary star. Don't you agree that both of these will also measure c as the speed of the light coming to them from the pair of distant stars in the binary star system?
 
  • #74
Q-reeus said:
Quite some time back I dabbled with the idea of detecting a one-way c variation based on differential phase-shift in adjacent optical fibers (no clocks). Never pursued it though once the realization came what detecting an actual one-way c anisotropy, by any arrangement, implies: https://www.physicsforums.com/showpost.php?p=3080684&postcount=64 - see last paragraph. Physics would be (inertial) frame dependent - period. I hesitate to rule that out absolutely, but it does tend to make one think rather more carefully.

I'm quiet aware of the consequences, which is why I expressed a lack of interest before defending the workability of the method. This is also behind my objection of calling an empirically equivalent model somehow physically distinguishable, of which LET is an example but other anisotropic models can also have similar physically moot content. Also why I said the only people it would have any bearing on is the Einstein is wrong crowd.

The notion that it would actually measure anything unexpected is far fetched to say the least. On the other hand theories like LET are no strictly invalidated. Just made moot by the lack of any empirical point or expanded domain of applicability. That could at least in principle change though.

ghwellsjr said:
Well now Q-reeus let the cat out of the bag. I was going to try to understand your setup, my_wan, but it really doesn't matter. Let's stipulate that your apparatus will work as you believe it will. Now the question is: will your apparatus ever be able to measure a one-way speed of light that differs from c?

Q-reeus didn't say anything I didn't already explain in this thread, after expressing a general lack of interest in actually seeing this experiment performed for that very reason. When you ask: "will your apparatus ever be able to measure a one-way speed of light that differs from c?" That depends on what you mean by differ. If you mean differ by establishing an "absolute" speed C, then no, as I already explained about relational variables. If measure a differing relation value C different than what we assume it to be, then yes if and only if it does differ relationally. And yes if space and time covary differently from what Relativity predicts. I can't even measure my nose without a relational value to measure it against with or without relativity theory, so that's nothing new.

By the way, we already know that in some sense GR predicts that the speed C cannot be an absolute constant. Einstein spent a significant amount of time in one of his books on GR making this point clear. So theories in which the speed of light is not constant in relation to some choice of metric internal to the model does nothing out of the ordinary to what is contained in GR. The only problem is that people keep mixing coordinate choices in as if it has absolute physical meaning.
 
  • #75
It was in the link that Q-reeus provided that I meant he let the cat out of the bag.

I have no idea what you are trying to say. I ask a simple question: will your apparatus ever measure a value other than c and you say it depends on what I mean by differ. The value of c is 299,792,458 meters per second. Will your apparatus ever measure a value other than 299,792,458 meters per second? I'm assuming that you can build an apparatus that has a digital readout on it that can display the measured value. I should stipulate that we are talking about an inertial measurement in vacuum--I should hope that goes without saying.

So now that you know what I mean by differ, will your apparatus ever measure a value for the one-way speed of light that differs from c?
 
  • #76
ghwellsjr said:
It was in the link that Q-reeus provided that I meant he let the cat out of the bag.

I have no idea what you are trying to say. I ask a simple question: will your apparatus ever measure a value other than c and you say it depends on what I mean by differ. The value of c is 299,792,458 meters per second. Will your apparatus ever measure a value other than 299,792,458 meters per second? I'm assuming that you can build an apparatus that has a digital readout on it that can display the measured value. I should stipulate that we are talking about an inertial measurement in vacuum--I should hope that goes without saying.

So now that you know what I mean by differ, will your apparatus ever measure a value for the one-way speed of light that differs from c?
To say that the "value of c is 299,792,458 meters per second" is awfully simplistic when many models have differing definition of both what constitutes a "meter" and what constitutes a "second". However, measuring the one way speed of light in a Newtonian sense it does. How you want to interpret that in the context of some model is not my problem.

The red letters: where you say digital readout. Apparently I failed to get even the basics of the measurement across. To perform this measurement requires at least dozens of measurements if not hundreds. A different measurement for every point plotted on a curve. To get a single measurement for a digital readout not only requires extreme accuracy with a highly accurate known light source intensity, but also requires making all the assumptions I was falsely accused of making. If I'm allowed to make all those assumptions that SR is in fact empirically valid in this respect then it might at least in principle be possible to read it on a digital readout, with enough accuracy and a predefined reference light source. Probably not technically feasible though.
 
  • #77
my_wan said:
Basically Born rigidity as he was the first to introduce the notion.
OK, I am certainly aware of Born rigidity. I have no issues with you specifying Born-rigid rotation as long as the angular velocity is fixed at one specific RPM.

However, Born-rigid motion does not in any way negate length contraction. The issue is not rigidity, it is the anisotropy of length contraction. If the one-way speed of light is anisotropic then length contraction is also anisotropic. This causes geometrical distortions even in a Born-rigid device such that the predicted experimental result is the same as for standard Einstein synchronization. You cannot measure anything other than what you assume.

my_wan said:
I did not assume Einstein synchronization was uniquely valid. I do not assume that relativity claims that Einstein synchronization is uniquely valid. I only assume it is one of an unknown number of equally valid solutions.
OK, then by this do I correctly understand that you now agree that it is impossible to measure the one-way velocity of c without assuming it via your synchronization convention?
 
  • #78
Having now gone over my wan's proposal in #61 and later expounded, I see no basic objection to a one-way differential detection per se. Do one run as described, then rotate the apparatus 180 degrees about an axis normal to the pipe rotation axis, and in principle you can detect a difference in c in two opposite directions. Problem is more refined versions have attempted essentially that with nothing positive yet to show: e.g http://arxiv.org/abs/1103.6086 - which seems basically similar in principle to my wan's. One team claiming positive results uses a quite different technique: http://arxiv.org/abs/astro-ph/0604145v1 - but note nothing more has been heard from them for several years now! A fairly up to date list of many different one-way (and two-way) tests is at http://arxiv.org/abs/1011.1318 Another not so up to date list is at http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/SR/experiments.html
 
  • #79
Q-reeus said:
Having now gone over my wan's proposal in #61 and later expounded, I see no basic objection to a one-way differential detection per se. Do one run as described, then rotate the apparatus 180 degrees about an axis normal to the pipe rotation axis, and in principle you can detect a difference in c in two opposite directions.
According to what principle? It certainly is not in accord with the principle of relativity.
 
  • #80
ghwellsjr said:
According to what principle? It certainly is not in accord with the principle of relativity.
Which principle of relativity would that be? The test itself is expected to be null, or more specifically returning a constant value of C regardless of alignment in space. Hence a null result would mean it is precisely in accord with the principle of relativity. Only if you presume the one way speed of light really is different can you suppose anything is not in accord with the principle of relativity. But that would be a consequence of the result, not the test.
 
  • #81
Q-reeus said:
Having now gone over my wan's proposal in #61 and later expounded, I see no basic objection to a one-way differential detection per se. Do one run as described, then rotate the apparatus 180 degrees about an axis normal to the pipe rotation axis, and in principle you can detect a difference in c in two opposite directions. Problem is more refined versions have attempted essentially that with nothing positive yet to show: e.g http://arxiv.org/abs/1103.6086 - which seems basically similar in principle to my wan's. One team claiming positive results uses a quite different technique: http://arxiv.org/abs/astro-ph/0604145v1 - but note nothing more has been heard from them for several years now! A fairly up to date list of many different one-way (and two-way) tests is at http://arxiv.org/abs/1011.1318 Another not so up to date list is at http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/SR/experiments.html

The setup in http://arxiv.org/abs/1103.6086 is sufficiently close to what I proposed to qualify the general idea, and expressed in reference [7] (Phys. Rev. D 45, 403–411 (1992)) therein. It summed up the point quiet well with:
[PLAIN]http://arxiv.org/abs/1103.6086 said:
Will[/PLAIN] [7] showed that experiments which test the isotropy in one-way or two-way (round-trip) experiments have observables that depend on test functions but not on the synchronization procedure. He noted that “the synchronization of clocks played no role in the interpretation of experiments provided that one is careful to express the results in terms of physically measurable quantities.”

I was worried that introducing a second leg, via beam splitters as done in http://arxiv.org/abs/1011.1318 would reintroduce the synchronization problem wrt the pair of detectors. So I was curve fitting lots of measurements to fit the speed c as some factor of diameter. However, after skimming through the paper I see that concern was unwarranted.

http://arxiv.org/abs/astro-ph/0604145 is very interesting for reason unrelated to an anisotropic speed c. It was after all a Doppler shift, not a speed of c carrying the Doppler information. To call it a measure of an anisotropic speed c is tantamount to claiming the Doppler shift measured by police radar is a measure a light speed anisotropy induced by the speeders car.
 
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  • #82
DaleSpam said:
OK, I am certainly aware of Born rigidity. I have no issues with you specifying Born-rigid rotation as long as the angular velocity is fixed at one specific RPM.

However, Born-rigid motion does not in any way negate length contraction. The issue is not rigidity, it is the anisotropy of length contraction. If the one-way speed of light is anisotropic then length contraction is also anisotropic. This causes geometrical distortions even in a Born-rigid device such that the predicted experimental result is the same as for standard Einstein synchronization. You cannot measure anything other than what you assume.
Born rigidity is not what negates the length contraction, it is merely a practical prerequisite for quantitatively defining length contraction in a given circumstance. Herglotz-Noether theorem is what negates the need for quantitative concerns about the effects of length contraction when defining raw uninterpreted measurement relations, i.e., raw uninterpreted experimental results.

It seems that you have come to the same conclusion by way of geometrical distortions that undo the very measurement being attempted. That is in fact the whole point of the Herglotz-Noether theorem here, and is not limited to just Einstein synchronization but also applies to Galilean synchronization in this particular context. That's what makes LET physically defensible.

The problem, as I have already stated, is that by claiming these types of distortions reintroduce absolute speed variances implies that coordinate choices have absolute meaning. I have no doubt that LET is physically valid, and even less doubt that SR is physically valid. Any attempt to try to prove otherwise is tantamount to trying to test the physical difference between this and that coordinate choice. The problem when models are created that different in these types of coordinate transforms is that people then often think this coordinate choice has some kind of uniquely valid reality.

DaleSpam said:
OK, then by this do I correctly understand that you now agree that it is impossible to measure the one-way velocity of c without assuming it via your synchronization convention?
By that if you mean do I expect a null result given the experiment I proposed, absolutely! Neither would such a null result invalidate LET, nor SR. The only thing worth bothering with even trying to detect is physically differing theories, not theories that merely operate differently solely on the basis of a differing coordinate choice. LET is SR as defined by the perspective of a particular choice of a Galilean frame. SR makes no claims to the contrary.
 
  • #83
my_wan said:
ghwellsjr said:
According to what principle? It certainly is not in accord with the principle of relativity.
Which principle of relativity would that be?
That would be Einstein's first postulate:
the unsuccessful attempts to discover any motion of the Earth relatively to the “light medium,” suggest that the phenomena of electrodynamics as well as of mechanics possesses no properties corresponding to the idea of absolute rest. They suggest rather that, as has already been shown to the first order of small quantities, the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good.1 We will raise this conjecture (the purport of which will hereafter be called the “Principle of Relativity”) to the status of a postulate
--from the second paragraph of Einstein's 1905 paper introducing Special Relativity. See also the beginning of section 2.
my_wan said:
The test itself is expected to be null, or more specifically returning a constant value of C regardless of alignment in space. Hence a null result would mean it is precisely in accord with the principle of relativity. Only if you presume the one way speed of light really is different can you suppose anything is not in accord with the principle of relativity. But that would be a consequence of the result, not the test.
The principle of relativity guarantees not that the test is null or the result is null but that there cannot be a test. It is not possible to measure the one-way speed of light, meaning that we cannot determine how long it takes for light to propagate between two points.

Consider this: in any inertial Frame of Reference, the one-way speed of light is defined to be c. That means that for an observer at rest in that frame, the one-way speed of light is c and because of this, the stationary coordinate clocks remote to that observer can be synchronized. But for an observer moving in that frame, the one-way speed of light, that is, the propagation time for light is not the same in different directions, which is why we have the relativity of simultaneity, which is why we cannot, even in principle, measure the one-way speed of light. The information we need to make the measurement simply is not available to us. The principle of relativity guarantees that.
 
  • #84
We seem to be circling around semantics mostly, but there is a fundamental point here that the principle of relativity is a product of coordinate independence.

ghwellsjr said:
The principle of relativity guarantees not that the test is null or the result is null but that there cannot be a test. It is not possible to measure the one-way speed of light, meaning that we cannot determine how long it takes for light to propagate between two points.
There is a test here. The test ask if the principle of relativity is a strictly valid postulate. Thus when you say the principle of relativity "guarantees", well then do the test and see if the "guarantee" holds. Yet somehow I was the one accused of presupposing the validity of SR in order to get the results?

Why might this be interesting to anybody (not me)? Because it has been said that measuring a one way speed of light was impossible as a result of the need to synchronize a pair of clocks. This is wrong, and I've learned that others have already demonstrated that here. Yet SR, as expected, remains valid as does LET.

The thing is that if you accept that a coordinate choice is not in itself a physical choice (coordinate independence) then you get the same effect without resorting to any dependence on the principle of relativity.

ghwellsjr said:
Consider this: in any inertial Frame of Reference, the one-way speed of light is defined to be c. That means that for an observer at rest in that frame, the one-way speed of light is c and because of this, the stationary coordinate clocks remote to that observer can be synchronized. But for an observer moving in that frame, the one-way speed of light, that is, the propagation time for light is not the same in different directions, which is why we have the relativity of simultaneity, which is why we cannot, even in principle, measure the one-way speed of light. The information we need to make the measurement simply is not available to us. The principle of relativity guarantees that.
So here you have used the Galilean coordinates of one frame o to say that the Galilean coordinates of another frame o' does not match, o \neq o'. Yet LET speaks in terms of the coordinate choice in which it is defined. In terms of coordinate independent this is tantamount to saying I have a theory that says 1 inch is 2.54 cm, such that 1 \neq 1'. Then arguing over whether we can measure the difference between 1 inch and 2.54 cm.

Einstein also brought up mechanics in the very 1905 quote you provided, where it said:
[...]suggest that the phenomena of electrodynamics as well as of mechanics possesses no properties corresponding to the idea of absolute rest.
In fact it was very well understood, apparently more so than today, prior to Einstein that mechanical variables did not have absolute values, meaning, or locations, only relational ones. Thus that simple statement is a claim that electrodynamics is a mechanical property.

This is trivially demonstrated by asking which of two meteors with a relational kinetic energy between them is the kinetic energy actually located at? Depends on which coordinate choice you use, but a coordinate choice is not in itself a physical thing. Hence that very quote validates the consistency of LET before ever even being published. Hence the notion that LET makes claims not already contained in SR is just plain wrong. Yet people still keep piling on o \neq o'as if it means that 1 inch can't mean 2.54 cm. Mechanistically, and independent of the principle of relativity, the location of kinetic energy is a function of the non-physical coordinate choice, just as the notion of a location itself, and distance derived thereof, is in SR. What the principle of relativity provided was an operational definition of coordinate independence under which laws could be given a coordinate independent form. It does not invalidate or quantitatively disagree with the coordinate dependent form of the same laws.

Hence the Einstein is wrong, and LET must be right, crowd is defining a false dichotomy. SR MUST be valid in order for LET to be valid in order for Einstein's claim that electrodynamics is mechanics to be valid. The only reason I bothered posting the one way speed c post was because it has been falsely said that the reason it couldn't be measured was due to the need to synchronicity two clocks. If you thought I was trying to make a experimental distinction between LET and SR I refuted that way back. Yet any model that does covary space and time differently from SR is detectable in principle.
 
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  • #85
ghwellsjr said:
I should stipulate that we are talking about an inertial measurement in vacuum--I should hope that goes without saying.

I want to come back to this because we tend to assume it a priori, since it makes things easier to conceptualize, even though GR doesn't allow this simplification. A couple of quotes to avoid my own explanation:
[PLAIN]http://aether.lbl.gov/www/classes/p139/speed/space-time.html said:
The[/PLAIN] speed of light is constant only in the absolute space-time frame, which is also called the Newtonian rest frame.

[PLAIN]http://www.physlink.com/education/askexperts/ae13.cfm said:
So,[/PLAIN] it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference].

Here I want to describe a situation where restrictions to local inertial measurements do not allow us to escape this simplification. This results from the fact that in GR time dilation is the result of depth of field, rather than gravitational acceleration alone.

If you have a massive hollow sphere then inside this sphere time dilation, relative to a far removed observer, will remain slowed to that on the surface. Yet, for an observer in this sphere, there no gravitational acceleration anywhere within the sphere. The spacetime inside is effectively flat and inertial.

Here's the problem. We know that ##c = \Delta x/\Delta t## such that the spacetime interval ##\Delta s^2 \equiv -\Delta t^2+\Delta x^2## is the actual constant. Now in this effectively flat region of inertial space we know that ##t \neq t'## relative to another far removed comoving flat inertial space such that the velocity ##c \neq c'##. This in spite of both spaces being both effectively flat and inertial, and two comoving observers in these respective regions can share a constant relative distance, yet still we have, as in GR, ##c \neq c'##.

Can we presume that the Universe as a whole has a constant gravitational depth? Possibly in principle, but extremely doubtful observationally or even a priori. Could the relativity of simultaneity then produce observational effects not otherwise locally observable?
 
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  • #86
my_wan said:
We know that ##c = \Delta x/\Delta t## such that the spacetime interval ##\Delta s^2 \equiv -\Delta t^2+\Delta x^2## is the actual constant.
Actually the spacetime interval is ##\Delta s^2 \equiv -c^2\Delta t^2+\Delta x^2##.
 
  • #87
my_wan said:
We seem to be circling around semantics mostly, but there is a fundamental point here that the principle of relativity is a product of coordinate independence.
The principle of relativity is not Einstein's Theory of Special Relativity. It's just his first postulate. The principle of relativity is also the first (assumed) postulate of LET. What distinguishes LET and SR is their respective second postulates. LET assumes (which is the same as postulates) that the propagation of light is c only in one inertial state of motion, the rest state of the ether. SR postulates that light propagates at c in any inertial state of motion. There can be no test or measurement to choose between the validity of these two postulates. Any test that would claim to indicate that light propagates at c in all directions and in all states of inertial motion will have a built-in assumption that presumes SR's second postulate. Any test that would claim to indicate that light propagates at different speeds in different directions and/or in different states of inertial motion will have a built-in assumption that presumes LET's second postulate. Any claim that there can be such a test is a claim that denies the validity of the first postulate and would also deny the validity of both SR and LET because both share the same first postulate.
 
  • #88
Thanks for the correction.

ghwellsjr said:
The principle of relativity is not Einstein's Theory of Special Relativity. It's just his first postulate.
I wouldn't necessarily boost an assumption to a postulate. I can assume the kinetic energy of two meteors on a collision course is contained in the meteor that is approaching the meteor I am standing on. That is neither a postulate nor gets me in any mathematical trouble with quantifying what's about to happen. In fact the fundamental mistake here is to assume that just because my equation presumptively associated the this energy with one of the two meteors entails a postulate is the problem with the whole Einstein is wrong line. Einstein did not associate velocity-vectors with points in a vacuum. LET attempted a perfectly reasonable extension which did. It is not the model LET attempted that is a problem. It is this boost in a LET coordinate choice to the status of a postulate which destroys validity. The validity of this "postulate" is destroyed by the same issue involved with trying to experimentally determine which meteor "really" contains the kinetic energy. Drop this "postulate" to a mere coordinate choice, as demanded by the simplistic mechanics of a pair of rocks, and the validity issues of LET goes away, and instead merely justifies SR. Once you accept that the differing speed c, as defined by LET, is the product of a coordinate choice rather than a relational physical state then LET also demands that the speed of light is constant wrt any given Galilean frame, in the same way SR claims it to be. This is evidenced by the fact that it provides no observable distinctions.


ghwellsjr said:
The principle of relativity is also the first (assumed) postulate of LET. What distinguishes LET and SR is their respective second postulates. LET assumes (which is the same as postulates) that the propagation of light is c only in one inertial state of motion, the rest state of the ether. SR postulates that light propagates at c in any inertial state of motion. There can be no test or measurement to choose between the validity of these two postulates. Any test that would claim to indicate that light propagates at c in all directions and in all states of inertial motion will have a built-in assumption that presumes SR's second postulate. Any test that would claim to indicate that light propagates at different speeds in different directions and/or in different states of inertial motion will have a built-in assumption that presumes LET's second postulate. Any claim that there can be such a test is a claim that denies the validity of the first postulate and would also deny the validity of both SR and LET because both share the same first postulate.

Promoting a coordinate choice to the status of a postulate obviously demands a varying speed of light. Much like I showed how relativity provides a method of defining ##c \neq c'##. It also demands that you explain which meteor the kinetic energy is really contained in. It's simply absurd to hold a coordinate choice up to the status of a postulate, and LET works better without it than with it. Even today classical thermodynamics is rife with so called extensive properties (state variables) in which the mean field limits which define them are inextricably dependent on a 'proper' Galilean frame choice. This coordinate choice promoted to "postulate" creates an insidious false dichotomy that goes well beyond SR and LET.
 
  • #89
I take it you don't agree with Einstein's position in his 1905 paper introducing SR?
 
  • #90
I was trying to work around a latex issue a few post back that apparently is only a problem with chrome. Figures showing up in strange places.
 
  • #91
ghwellsjr said:
I take it you don't agree with Einstein's position in his 1905 paper introducing SR?

WOW! After all that explaining why the SR version is superior!
 
  • #92
my_wan said:
ghwellsjr said:
I take it you don't agree with Einstein's position in his 1905 paper introducing SR?
WOW! After all that explaining why the SR version is superior!
Do you agree with this statement:
If at the point A of space there is a clock, an observer at A can determine the time values of events in the immediate proximity of A by finding the positions of the hands which are simultaneous with these events. If there is at the point B of space another clock in all respects resembling the one at A, it is possible for an observer at B to determine the time values of events in the immediate neighbourhood of B. But it is not possible without further assumption to compare, in respect of time, an event at A with an event at B. We have so far defined only an “A time” and a “B time.” 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.
 
  • #93
ghwellsjr said:
Do you agree with this statement:
If at the point A of space there is a clock, an observer at A can determine the time values of events in the immediate proximity of A by finding the positions of the hands which are simultaneous with these events. If there is at the point B of space another clock in all respects resembling the one at A, it is possible for an observer at B to determine the time values of events in the immediate neighbourhood of B. But it is not possible without further assumption to compare, in respect of time, an event at A with an event at B. We have so far defined only an “A time” and a “B time.” 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.
Of course I agree. Also note what I marked in red. This indicates that we are of course naturally talking about a definition, not a uniquely valid definition but simply a valid definition. Just like coordinate choices are non-unique but valid definition of metrics, as is which meteor the kinetic energy is located at.
 
  • #94
Well, then, I'm wondering why you made this statement:
my_wan said:
It is also possible to measure the one way speed of light...
 
  • #95
my_wan said:
That's what makes LET physically defensible.
I don't think that LET is on-topic for this thread. However, I am in agreement with the remainder of your response.
 
  • #96
my_wan said:
Because it has been said that measuring a one way speed of light was impossible as a result of the need to synchronize a pair of clocks. This is wrong, and I've learned that others have already demonstrated that here.
Here is where you and I disagree. The definition of the synchronization convention and the definition of the one-way speed of light are the same thing.

Suppose you have a flash bulb and a ring of detectors at some fixed distance d away from them. The flash bulb goes off at t=0 and the detectors each detect a flash. When does each detector detect the flash? If they all detect them at the same time, t=d/c, then the one way speed of light is c and they detect them simultaneously. If they detect at different times, then they are not simultaneous and the speed of light is not c for each path. The one way speed of light any your synchronization process are the same thing.

Your claims to the contrary are incorrect.
 
  • #97
[PLAIN]http://arxiv.org/abs/1103.6086 said:
However,[/PLAIN] Will [7] showed that experiments which test the isotropy in one-way or two-way (round-trip) experiments have observables that depend on test functions but not on the synchronization procedure. He noted that “the synchronization of clocks played no role in the interpretation of experiments provided that one is careful to express the results in terms of physically measurable quantities.” Hence the synchronization is irrelevant for our one-way speed of light test since we express our results in terms of physically measurable quantities.

That's why I said it. Already said that to.
 
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  • #98
DaleSpam said:
Here is where you and I disagree. The definition of the synchronization convention and the definition of the one-way speed of light are the same thing.

Suppose you have a flash bulb and a ring of detectors at some fixed distance d away from them. The flash bulb goes off at t=0 and the detectors each detect a flash. When does each detector detect the flash? If they all detect them at the same time, t=d/c, then the one way speed of light is c and they detect them simultaneously. If they detect at different times, then they are not simultaneous and the speed of light is not c for each path. The one way speed of light any your synchronization process are the same thing.

Your claims to the contrary are incorrect.

I don't have a flash period, I have a light on 100% of the time. Neither do I have a t=0 anywhere period, or t= anything. Nor is there any pair of events that I measure for comparison. The pure geometry does all that for me, and if you want to make a case about it then respond to what I already responded to. Instead of this t= strawman when clearly i do not label t= to say what RPM something is rotating. I don't care when its rotating nor when the light was on.
 
  • #99
my_wan said:
Originally Posted by http://arxiv.org/abs/1103.6086
However, Will [7] showed that experiments which test the isotropy in one-way or two-way (round-trip) experiments have observables that depend on test functions but not on the synchronization procedure. He noted that “the synchronization of clocks played no role in the interpretation of experiments provided that one is careful to express the results in terms of physically measurable quantities.” Hence the synchronization is irrelevant for our one-way speed of light test since we express our results in terms of physically measurable quantities..
That's why I said it. Already said that to.
OK, now I understand what's going on. That paper, which you said, "is sufficiently close to what I proposed to qualify the general idea" is not talking about measuring the value of the one-way speed of light or measuring the propagation time of the light traveling in one direction. Rather it is measuring the constancy of the speed of light which does not require synchronized clocks.

The wikipedia article on "The one-way speed of light" that I encouraged you to read back in post #60 makes this clear. If you look at the section entitled "Experiments that can be done on the one-way speed of light" you will see that "it is possible to carry out experiments that measure a change in the one-way speed of light". As the article points out, "In such experiments the clocks may be synchronized in any convenient way, since it is only a change of speed that is being measured." In other words, it doesn't matter if the clocks are synchronized at all or even if actual clocks are used which is the case in the paper and in your proposed experiment.

But these experiments cannot and do not claim to measure the value of the speed of light which is what we mean by the statement that the one-way speed of light cannot be measured.

The experiment in the paper (and I presume your proposed experiment) is measuring how the speed of light changes during a period of 24 hours as the Earth points the apparatus in different directions and they did measure a sinusoidal pattern. They pointed their apparatus along a North-South direction to minimize the difference. If they were to repeat their experiment on the equator instead of at Toronto, this sinusoidal pattern may be eliminated and if they were to point their apparatus along an East-West direction, they would maximize the amplitude of the sinusoidal pattern, I believe.

Have you thought about why there should be a sinusoidal pattern with a period of approximately 24 hours? Are they measuring an actual change in the one-way speed of light as the apparatus is pointed in different directions? Are they now finally measuring an ether wind?
 
  • #100
ghwellsjr said:
The wikipedia article on "The one-way speed of light" that I encouraged you to read back in post #60 makes this clear.

[PLAIN]http://en.wikipedia.org/wiki/One-way_speed_of_light said:
The[/PLAIN] "one-way" speed of light from a source to a detector, cannot be measured independently of a convention as to how to synchronize the clocks at the source and the detector.
and:
[PLAIN]http://en.wikipedia.org/wiki/One-way_speed_of_light said:
Although[/PLAIN] experiments cannot be done in which the one-way speed of light is measured independently of any clock synchronization scheme,[...]

And I'm telling that is wrong, as the sources I quoted and will quote again states, again repeating myself over and over on this point only to be ignored and told I said something else. Yet here you are pretending I must not have even read it! Was it me not reading when I bent over backwards explaining the superiority of SR and have you response say I must not agree with SR?

Get this straight:
1) The ONLY timing device is the RPM of the pipe, period.
2) The ONLY variable this relates to is a distance, not time.
(Hence when wiki says "synchronize clocks" it is dead wrong.)
3) The ONLY assumptions being made is Newtonian, in spite of knowing that is going to be wrong.
Only by insisting that my tape measure is a clock can you claim I am synchronizing a pair of clocks. Hence this is a one way speed measurement in precisely the same way Michelson Morley was a two way speed test.

Note the red letters:
[PLAIN]http://arxiv.org/abs/1103.6086 said:
Will[/PLAIN] [7] showed that experiments which test the isotropy in one-way or two-way (round-trip) experiments have observables that depend on test functions but not on the synchronization procedure. He noted that “the synchronization of clocks played no role in the interpretation of experiments provided that one is careful to express the results in terms of physically measurable quantities.” Hence the synchronization is irrelevant for our one-way speed of light test since we express our results in terms of physically measurable quantities

Also in the other paper:
[PLAIN]http://arxiv.org/abs/1011.1318 said:
However,[/PLAIN] Will [49] showed that experiments which test the isotropy in one-way or two-way (round-trip) experiments have observables that depend on test functions ##a(v^2)##, ##b(v^2)##, and ##d(v^2)## but not on the synchronization procedure. He noted that “the synchronization of clocks played no role in the interpretation of experiments provided that one is careful to express the results in terms of physically measurable quantities”. Hence the synchronization is largely irrelevant.

ghwellsjr said:
The experiment in the paper (and I presume your proposed experiment) is measuring how the speed of light changes during a period of 24 hours as the Earth points the apparatus in different directions and they did measure a sinusoidal pattern.
The only reason for comparing changes over such periods of time not to measure "a" one way speed of light, but to search for differing one way speeds. Hence in my setup, instead of dual directional beams at different times, I use differing RPMs to establish a numerical value of c as defined by one, and only one clock, and one and only one tape measure. Hence my approach was to measure "a" one way speed where synchronization is irrelevant.

Even if you suppose my method is invalid you still have to invalidate E Riis et al, Phys. Rev. Lett, 60(2) (1988), and C. M. Will, Phys. Rev. D 45(2), 403-411 (1992), to justify the false claims on wiki.
 
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