SR and one-way speed of light tests

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The discussion centers on a proposed one-way speed of light test aimed at challenging Einstein's Special Relativity (SR) by measuring light's speed in the presence of an "ether wind." The test involves two clocks placed 10 km apart on Earth's surface, firing a laser in both directions to compare time differences, which proponents believe could reveal variations in light speed due to Earth's motion through the ether. Critics argue that existing two-way tests, like the Michelson-Morley experiment, have already shown no detectable ether effect, and they question the validity and necessity of the proposed one-way test. They also point out that GPS technology, which relies on the constancy of light speed, effectively demonstrates SR's principles, despite claims that it cannot serve as a one-way test. Ultimately, the conversation highlights a divide between those advocating for new experiments to test light speed and those who believe current evidence sufficiently supports SR.
  • #31
Must be a local phenomena. Otherwise a lot more telecommunications businesses would report some trouble in syncronyzing their clocks...hell, if nothing else then for sure scientific laboratories could not merely use c value of light to syncronize experiments in different laboratories (i.e. in a lab I toured in, they have to take into account the travel time of a signal to another lab across the globe to make as much of a timeing as possible). They always use light speed = c no matter when, and always get precise results.

Must be a local ether centered around his locale :wink:
 
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  • #32
Brad
If the variation detected was local it would have a cyclic period of 24 hours - one calendar day. But its period was 23hrs 56mins - one sidereal day. This rules out a local factor. Whatever is causing the change has to be in the direction of the distant stars, i.e. of galactic origin.
This result is not what I would've expected. But it strengthens the argument in doing a proper one-way light speed test. It suggests that the result will be >6.7nS. But like the De Witte test, the laser should fire continuously over several weeks to record maximum/minimum values.
Note: because of the great speed of light, clock sync error would not show in telecommunications systems. The errors are there, but they are too small to show. This test will prove that the relative speed of light changes.
 
  • #33
First off, why would it being local necessitate it be a 24 hour period??


And second of all, this was not the run of the mill telecommunications system.


Third, a system such as the one you cite is prone to many various impurities over the course of weeks. Even if it is burried underground, things such as lunar tidal forces can cause some distortions to occur, as can power usage, and other cycles.
 
  • #34
Originally posted by wisp
But it strengthens the argument in doing a proper one-way light speed test. It suggests that the result will be >6.7nS.
That is well within the ability of the GPS system to detect. I looked over the experiment and I can't claim I understand it completely - but it looks like he's stretching the precision of his apparatus. His measurements are likely the result of experimental error.

I realize this is the sort of experiment and paper you would jump on, but PLEASE consider the credibility of the source. Has the paper been peer-reviewed and published? If no, consider that there is probably a REASON why it hasn't been published: its flawed.

Incidentally, he mentions GPS - he says the failure of GPS to detect his effect is due to the variation of the speed of light exactly cancelling the time dilation for the signal transit time. Those damn laws of the universe are conspiring against us again. Except that that ignores the other part of the time dilation: The part where the time dilation causes the clocks to become out of sync with each other. Sorry, self-contradictory arguement.

And again - if there was an aether wind, the MM experiment would have detected it, your understanding of the MM experiment to the contrary.

Wisp, you're repeating the same flawed arguements over and over again. That doesn't make them right.
 
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  • #35
That's right, it's also a lesson in SR- the MM interferometer would've detected a difference in the fringes 100 years ago.
 
  • #36
Originally posted by schwarzchildradius
That's right, it's also a lesson in SR- the MM interferometer would've detected a difference in the fringes 100 years ago.
A remarkable achievement, no doubt - one worth a Nobel prize.
Any MM type experiments cannot measure the ether flow, only a one-way test can.
Measuring the aether flow is precisely what the MM experiment was designed to do. . Wisp, be aware - you're now saying that the MM experiment didn't accomplish what they said it accomplished - that their experiment was flawed. And they got a Nobel Prize for it. I submit you need to reread their experimental method. The river analogy specifically.
 
  • #37
Brad
More info on the significance of the sidereal period is given in the document http://pages.sbcglobal.net/webster.kehr/files/Detection.pdf it takes a few minutes to download, but it's worth reading the "ether wind detection".
The significance of the De Witte experiment is that it seems to give a plausible result. How De Witte interprets this is another matter.

With regard to the MM null result, if the motion of the Earth through the ether caused light to travel slower in the perpendicular direction by a factor of gamma. Then the MM result would always be zero. If this is true, which it is, then the MM test (which was designed specifically to measure the ether flow) cannot rule out the possibility that the ether exists, if the result is null. This gamma factor, which affects perpendicular light speed is called jiggle.
 
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  • #38
Originally posted by wisp
Brad
More info on the significance of the sidereal period is given in the document http://pages.sdcglobal.net/webster.kehr/files/detection.pdf it takes a few minutes to download, but it's worth reading the "ether wind detection".
The significance of the De Witte experiment is that it seems to give a plausible result. How De Witte interprets this is another matter.

With regard to the MM null result, if the motion of the Earth through the ether caused light to travel slower in the perpendicular direction by a factor of gamma. Then the MM result would always be zero. If this is true, which it is, then the MM test (which was designed specifically to measure the ether flow) cannot rule out the possibility that the ether exists, if the result is null. This gamma factor, which affects perpendicular light speed is called jiggle.


The link you provided was a deadlink.
[edit] to me anyways. My network has been very unstable, so I will try again later to make sure it isn't truly a dead link[/edit]

And second of all, how will an ether influence something perpendicular? The ether is a (debunked) medium in which light is thought to travel in. It is supposed to be stationary. Earth's motion (notice, only the earth) through the ether is what would cause a difference. Such a thing can only occur in the direction of movement, not perpindicular in which there is no movement.
 
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  • #39
Brad,
I've fixed the link on my post, capital D not small d, try it again.
The ether of old is plain and uninteresting. But wisp space ether is a different kind. For a start, matter does not push through it, but is part of it. If you make a hole in wisp space, it distorts it creating a spherical fractal pattern around the hole. This pattern is a matter-fractal (fundamental particle) and as it moves through wisp space it's pattern creates an infinite series of waves - quantum waves. This ether and matter interact in ways that create many interesting effects: relativistic mass, jiggle dilation...
 
  • #40
Now you are just adding unecessary things. Not only does this 'infinite' wave thing not make sense, it doesn't explain yet the perpindicular motion.
 
  • #41
Brad
For a fuller explanation on what relevance this has, you will have to read 6 pages of wisp theory - section 7.6.3 (jiggle dilation) through to section 7.7 (The Michelson-Morley Experiment), see
http://www.kevin.harkess.btinternet.co.uk and select chapter 7 - wisp and SR: Fundamentals.
It gives a convincing argument as to why light slows in the perpendicular direction only, which gives a null result. Of course this is moving into theory speculation and this should not interfere with the results of experiments that have been done.
 
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  • #42
Ok I read it but there are actually 2 issues that are wrong aside from the whole concept itself.

1) If the jiggle effects light perpendicularly, why does it not also do so from the reverse direction. I.E. If light is traveling in the x direction, should not the jiggle from both the positive y and negative y directions create a jiggle that effectively cancels out?

2) What about the z direction? Earth does move through space, and the z direction is indeed perpendicular. Now either the jiggle effects cancel out like they should in the y direction, OR light should be shifted over a direction because it gets a velocity shift in that direction.
 
  • #43
Brad
Q1) If the jiggle effects light perpendicularly, why does it not also do so from the reverse direction. I.E. If light is traveling in the x direction, should not the jiggle from both the positive y and negative y directions create a jiggle that effectively cancels out?

Ans: No. The wave pattern of light moves in the x direction, but its electromagnetic components move at right angles to its motion, in the y and z direction, and they move in jiggle planes, see wisp theory 7.6.3 jiggle dilation and fig 7.6 for full explanation.
An analogy would be if you imagine jiggle planes as a lot of shaking escalators side by side. If you walk along one you will get shaken about but will not loose speed, as the gains in speed will be canceled out by the losses. But if you walk across the escalators your motion will be hampered, because the gains and losses don't match. Light doesn't change direction, but the electromagnetic force that drives it is weakened by jiggle, and so it propagates slower.


Q2) What about the z direction? Earth does move through space, and the z direction is indeed perpendicular. Now either the jiggle effects cancel out like they should in the y direction, OR light should be shifted over a direction because it gets a velocity shift in that direction.


In a direction perpendicular to the Earth's surface the jiggle effect reduces as you move away from the Earth. If the MM experiment were carried out in deep space, it would show a positive result, as there would be no jiggle (assuming that the matter in the arms and mirrors did not create jiggle.
So all directions (close to the surface of the Earth) perpendicular to the motion of the Earth through the ether are affected by jiggle dilation.
 
  • #44
Professor Siu Au Lee
Colorado State University

Is proposing to carry out a one-way light speed experiment to see if the speed of light is linked to a universal reference frame.

If this experiment is done without mirrors and is similar that proposed above, it should give a positive result. The universal reference frame is wisp space (ether).

http://www.colostate.edu/Depts/Physics/People/faculty/lee.html
 
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  • #45
Isn't it convinient that the z direction isn't effected at all. Any direction can be perpendicular to the Earth's surface. And the light need not be alligned in the x and y. It could be the z and x, or the y and z or any combination thereof in between unless it is strictly polarized.
 
  • #46
Your right, Cartesian xyz coordinates do not map well on a spherical surface. But it still holds that if jiggle affects perpendicular motions of light relative to the Earth's direction through the ether, the results still hold. If the xyz axes move as the Earth rotates then jiggle affects different parts of the xyz axes. The end result is the same though.
In any direction, as you move away from the Earth's surface the jiggle effect drops off.
 
  • #47
Summary of reasons why a one-way light speed test should be done.
1. Wisp theory offers a serious challenge to Einstein's claim that the speed of light is constant. The theory has a solid foundation and is credible. See http://www.kevin.harkess.btinternet.co.uk/ and click on See Reasons why Einstein was wrong and click on one-way test.
2. A one-way electrical pulse test done in 1991 by Roland DeWitte produced a clear positive result showing an ether wind in the direction of Leo.
3. Earlier tests by Dayton Miller (two-way interferometer MM type) although flawed because of "jiggle dilation effect" were successful in producing a small positive result, because they were carried out atop of Mt Wilson, where jiggle effect is reduced. There is evidence that the work of Miller was quashed by Shankland's review under guidance from Einstein. See http://www.orgonelab.org/miller.htm
4. Miller's work shows that the ether flow is roughly perpendicular to the axis of the Earth. But because of the Earth tilts 23.5 degrees, the positive result will be approx 40% of its value had the ether flow been parallel to the Earth's orbit. The maximum and minimum value of the one-way speed of light time difference will change according to the sidereal period (23hr 56min), so results should be recorded every hour over a period of a few weeks to establish good data.

Reasons for not doing the test are loss of credibility for challenging Einstein's views - ether researchers have never been given serious credibility. And belief that GPS is so accurate that it would have found a change in the speed of light by now.
One things for sure, the centenary of Einstein's SR will also mark its downfall, as evidence against his theory is great. If this one-way test is done properly it will either strengthen Einstein's SR (good of centenary celebrations) or play a mayor part in its demise. All issues for and against Einstein will come to a head in 2005.
 
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  • #48
Yes, of course evidence against SR is bountiful. That's why the scientific community hates SR. Oh wait they don't. Lemme guess, it is part of the conspiracy to maintain some hidden agenda?
 
  • #49
Originally posted by Eyesee
Gravity affects light's motion so any "speed of light tests for anisotropy" would say more about the characteristics of our gravitational field than whether the speed of light is constant for all observers.
We can do both. Ain't technology great?
But it's obvious from the doppler shift that the speed of light is not constant for all observers, contrary to the ridiculous interpretation of it using SR.
Doppler shift works just fine with a constant speed of light.
And belief that GPS is so accurate that it would have found a change in the speed of light by now.
GPS can be used to measure your tee shot or fly a cruise missle down the street, hang a left at the corner and fly in the top left window of the second building on the right. Its accurate.
 
  • #50
Even though the GPS is a very accurate and finely tuned system, it cannot be used as confirmation that the speed of light is constant, as this has not been properly checked, it's only inferred. I am convinced that it would work with or without an ether flow.

My reasons for having doubts about the speed of light being constant are:
1. Special relativity is flawed and unnecessary. Einstein introduced it simply to explain the Lorentz force law, as he and others believed that ether theories could not support it. However, he's wrong, see wisp theory - chapter 8 - equation set 8.4. http://www.kevin.harkess.btinternet.co.uk/wisp_ch_8/wisp_ch_8.html
It proves conclusively that there is no need for a special theory that joins space with time, as an ether medium can support the Lorentz force law.
2. No one has done this simple one-way light speed test. Roland DeWitte did a one-way electrical test and got a positive result that varied with a sidereal period. Sidereal variations can only be of cosmic origin and not of local origin, which would vary according to the calendar day.
(Miller's results also showed sidereal variation and so cannot be of local origin, and he definitely ruled out local heating effects).
3. Ether theories can produce all of the relativistic effects that result from special relativity without the need to have the speed of light constant.
These include: Doppler effects (wisp ch 9), e=mc^2 (wisp ch 10), mass increase (wisp ch 7), Lorentz symmetry (wisp ch 8), etc.

I believe that the ether flow affects the GPS system, but its effect is symmetrical and the system self corrects any errors, effectively removing any offset ether drift errors. Errors are removed every minute/hour and so ether flow errors never build up to show a problem.
I found some data on optical tracking of low orbiting satellites. See http://www.celestrak.com/columns/v03n02/
The optical tracking of GPS, if done, cannot be better than +/- 0.05 degrees accuracy. This equates to satellites being +/- 23km out of position without being optically detected. I doubt that GPS satellites are even checked to this resolution. A north-south ether wind could fool GPS by this amount without it being optically picked up. How can the accuracy of GPS one-way tests be verified if the positions of the satellites cannot be checked optically?

If someone does this simple one-way light speed test its result will I'm sure make history. A null result will prove Einstein was right and ether theories are wrong - good news for SR centenary celebrations in 2005.
A positive result showing sidereal variation will prove the ether exists and end SR. But GPS will carry on working regardless.
 
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  • #51
Even as a supporter of VSL it never ceases to amaze me how often someone tries to redo something done multiple times just to prove SR in some way wrong. Let's see, besides multiple tests over the years along the same lines as the now famious experiment that tried to detect an Aether drift,(By the way, it was originally spelled AETHER, not ETHER, we have tests with atomic clocks showing time dilation to be correct(Another aspect of SR), we have observations generally showing no strong variation from C, even those that are used to supply a time variable C, and the actually challanged aspect of Lorentz was originally proposed by him while he upheld the notion of the Aether.

Now, if you want to follow the same logic you are using why not run the test in say a moving rocket? If the Earth's movement through this Aether is supposed to generate a drift I would think it would be safe to say that a faster moving object should be able to produce even a stronger drift, perhaps this time one measurable, since in all repeatable experiments to the present the Earth never produced a measurable one.

You say if this one-way test of SR was conducted and it got a Null reading that would silence the Aether side? I'd say wrong. The concept of this aether is very popular amongst a lot of folks and actually has its own scientific publications and groups. I've even noticed on rare occasions some articles in LANL outlining what amounts to classical Aether ideas. The little terrible infant, as Einstein called it is as much alive in some minds as it was before Einstein and all the tests since then. People tend to believe what they will no matter the evidence presented to them. Scientists themselves are not beyond this as Kip Thorne rather aptly pointed out in his book on Einstein's legacy with the example of many early on and modern great minds who have refused at times to accept an idea, later proven to be correct.

Personally, I'd suggest running the experiment would be a waste of time, except perhaps to convince you, however, if that would convince you I'd suggest trying to simply duplicate some of the original experiments in a bit more modern fasion with more modern equiptment. I've seen a lot of quotes over the years on supposed experiments that showed non-null readings. Most all of these tended in the end run due to errors of one form or another and general could never be repeated. Even if that experiment you quoted was correct I'd still find it odd that all the tests down through the years have never reported the same before this. Some of those tests were conducted by people who supported the Aether concept at the time.

Newton's absolute space and absolute time Aether is dead in the water. But, doing a modern version of the test might be an interesting exercize in general. There is an aether of sorts well known in quantum theory commonly called the zero point field. But it has no absolute time quality. Also, we do have a certain motion against a background known as our motion in relation to the CMB.
 
  • #52
Paultrr

SR is still a very successful theory that fits in well with modern science, and no one would challenge it unless they had good reason.
Wisp theory developed form a very simple (but different) idea. The focus of the theory is to explain how force and matter interact, and not to challenge SR.
When I realized that a simple one-way test would give a positive result, I thought that was the end of wisp theory. If I find clear evidence that a simple one-way test would give a null result, then I would accept it, but the evidence is not there.
My bet is that SR will fail because the speed of light is not constant. However, other aspects of SR - time dilation equation, relativistic mass increase, etc - will still stand.
 
  • #53
David Waite runs an interesting group on MSN about relativity and he pointed out something in there that is very true from the original papers of Einstein. Relativity only shows C is constant in the vacuum and that vacuum state has given conditions that qualify it. If, in the history of this universe those vacuum conditions have altered then C would have altered itself. Some recent observational data suggests that C varies with time. There have been some articles on this published over the last few years. Part of this is considered connected to the accelerated expansion issue. So part of the problem is what does one mean by constant?
 
  • #54
Paul:
Some recent observational data suggests that C varies with time
Do you have some links to papers reporting these observations?
 
  • #55
I haven't really read through this, but:

http://arxiv.org/abs/astro-ph/9808291
http://www.arxiv.org/abs/astro-ph/0012539

Detailing variations in the fine structure constant, alpha. Alpha is related to c, and so this can been seen as evidence for past differences in c. Or maybe their observations were inaccurate.

Varying c don't destroy SR per se, but would require some sort of variation in the behaviour of the universe. Some other developments on relativity also imply the existence of Varying C.

See also http://physicsweb.org/article/world/16/4/9/4
 
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  • #56
Thanks FZ+.
Detailing variations in the fine structure constant, alpha. Alpha is related to c, and so this can been seen as evidence for past differences in c.
Leaving aside whether a time-varying alpha implies a variable c or not, the observations of possible variations in alpha over cosmological time (such as those in your links) got folk excited for a while. Then came Bahcall, Steinhardt and Schlegel's paper:
http://www.sns.ias.edu/~jnb/
(click on "Quasar Adsorption and Emission Lines", then on "emission lines")

Great work, restrained commentary on the other works.
Or maybe their observations were inaccurate.
Their observations were probably OK; their analysis pushed too far IMHO.
 
  • #57
That was a good one. Might I suggest all the following:
http://www.msnbc.com/news/791205.asp?cp1=1
http://www.discover.com/apr_03/featspeed.html
http://arxiv.org/PS_cache/gr-qc/pdf/0112/0112011.pdf
Webb et al., Phys. Rev. Lett. 87 (2001) 091301, preprint
astro-ph/0012539
http://pvanhove.home.cern.ch/pvanhove/PopularScience/NewScientist/isnothings.html

There are other quotes of these observations and other references out there. Answer this onme question. Under SR and GR the speed of light is constant in a specific vacuum state. Even Einstein knew Light slowed down when it say enters the atmosphere or a different medium. Was the vacuum state during inflation the same vacuum state we have now? If, and current obeservations back this up there is some form of exotic energy that causes the expansion to accelerate that same exotic energy must be altering our vacuum state with time. If the vacuum state changes then the medium has changed and so has the speed of light. If the vacuum state during inflation was different from that state discussed by SR and our present vacuum state is slowly changing then it is fully logic to conclude that C has altered over the course of the history of cosmic evolution.
 
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  • #58
I agree by the way those observations need polished up as well as the conclusions, but what I mentioned above is known fact so the logic that C changes with time is sound. Has anyone found it interesting that the main proponent of VSL happens to be a friend of none other than Smolin himself? Here's Smolin telling us with his Loop Quantum Field Theory that space-time breaks down into discrete units past a certain scale. He tells us that time ceases to have meaning at this scale. Without Time there is no keeper of C, so to speak. If the background vanishes at a certain scale, which is what that theory implies then so does the restraint of the vacuum which actually is that background. Now you know why they are strong friends and what their common link is. They both, in different ways see Nature as telling us something about being too narrow in our views at times. Most of this modern thought came about by observation and through quantum mechanics.
 
  • #59
Paultrr,

The observations quoted in the links you gave are a subset of those referred to in the Bahcall et al paper (see section 8.1, "The Many-Multiplet method").

For those who've not read all the papers, the key difference between the two observational approaches is:
->the "Many-Multiplet" method involves many potential systematic errors, and extensive theoretical calculations, all of which the authors of the papers have gone to great lengths to try to identify and account for.

-> the Bahcall approach involves the ratios of two emission lines from the same ion, many sources of systematic error cancel each other, and no theoretical calculations need be done.

The two sets of observations produce conflicting results; the Many-Multiplet ones show alpha has changed over cosmological time; the Bahcall one that it didn't. As they are all measuring essentially the same thing, at least one set will be shown to be wrong.

You said:
but what I mentioned above is known fact so the logic that C changes with time is sound
All I would point out here is that there is no observational consensus that alpha has changed over cosmological time.
 
  • #60
wisp: to my knowledge no such one-way speed of light test has been done!
Have you considered doing this experiment yourself?

There was also some discussion of your idea on the superstringtheory forum:
http://superstringtheory.com/forum/eluboard/messages6/23.html
 
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