VSL Varying Speed Of Light

wimms

Re: Re: VSL book

Originally posted by russ_watters
You keep using those words. I don't know where you are getting them and I don't know how else to say it: The fact that C is constant in all reference frames is IMPERICAL DATA. Its not a postulate, assumption, stipulation, or other baseline position made for mathematical convenience. You're still looking at Relativity backwards.
bs. constant C is very first sentence of SR. its literally postulate. That the ideas to create SR came from empirical data is irrelevant. And value for c isn't even part of SR. And that it matches empirical data is the only reason its accepted.
I don't really understand what you argue here.

"Why?" is a philosophical/religious question. But Einstein most certainly did explain "HOW?" it happens. "HOW?" is the mathematical derivation itself. And the question of whether a mathematical model is a real extension of a physical reality is an interesting one, but it is also largely philosophical. As far as scientists are concerned, if it makes an accurate prediction, its a real extension of physical reality.
Are you saying that all scientists as positivists? I see two-sided razor here, on one side this is nice way to be open for unexpected ideas, but on other hand this is nice way to close you eyes on possibilities.
Mathematical derivation itself may contain components that cancel out in certain conditions. You say these components do not exist. I'm not saying they do, I'm asking if the possibility exists that they might.

Also, mechanisms are unnecessary here and are somewhat linked to the "why?". What is the mechanism by which C stays constant? Dunno - maybe a later theory will answer that. Maybe its just something God decided. Either way, it doesn't change the fact that C is constant and it doesn't change the theories that use the fact that C is constant.
Exactly about this I am talking. Is there a possible mechanism due which we observe C always as constant.
Any theory that will answer that must explain why we observe C as a constant.

I'm going to have to invoke Occam's razor again. It makes more sense to conclude from observing through imperical data that shows C is a constant and T is a variable, that C is a constant and T is a varible. You're going back to 'the universe is conspiring against us' position again.
I'm not about conspiring. I'm about possiblity that variations cancel out for us. 10 spatial dimensions that noone can ever detect is consipiring. Go apply your razor on strings.

You have it almost exactly backwards. You don't need a theory to know how to observe something. And generally, before you can have a theory, you need the data. You're putting the cart before the horse. Example: The MM experiment confused the hell out of M&M, but it was data and they accepted it. It was years later that a theory was constructed that adequately explained their data. The exception is theories that are built on other theories.
bs again. Whole criteria for being theory is requirement to offer predictions that can falsify theory. I've never heard of empirical data about strings. Have you?

Discarding the theory completely can hardly be called "rephras[ing]" it. It can of course be expanded - and thats not even close to the same as what you are proposing. Example: Newton vs Einstein's gravity.
Whats the bloody matter with you? What makes you say I'm discarding it? I've never said C is observable as VSL. I repeat: I'm ASKING if variations of C could manifest itself as some other phenomena.

Can't you really understand what I'm asking? C isn't dimensionless. It is ratio of distance and time. To keep the ratio constant while having variable time implies variance of meaning of distance. And that the measurement we make is dictated by time of frame we are in. If we accept that time flow can vary, then we must accept that meaning of distance must vary accordingly, else we couldn't observe constant C locally. Now, if we don't have absolute time, and we don't have absolute distance, then why should there exist absolute C? Obviously, we observe one. Still, imo, question is valid. How would we observe world around us, if speed limit of U varied?

String theory is an example of expansion - but it doesn't change the fundamental principles of relativity. It does not claim VSL. Just like the above, you're confusing expanding on a theory with discarding it completely. There is a huge difference.
Er, what does fundamental principles of relativity has to do with precise value of C in specific point of universe?

Sounds like you already know that scientists have a different explanation from what you prefer.
I don't prefer anything. I'm inquiring of possibility. If I'll need to compute, I'll use methods that scientists have accepted. This doesn't forbid me from inquiring unconventional ideas. AND this doesn't forbid you from explaining why they'd be ruled out.

Sure. Those quotes display a lack of understanding of the mechanism behind refraction. Or to be nice, the variability of C is a mathematical convenience, used in refraction calculations, which leads to a very common misunderstanding of the mechanism behind refraction. I'd bet my last paycheck that quote came from a site who'se purpose is to try to refute relativity.
Could you please explain in simple way, what do you mean? Are you saying that c is same inside water, air, fiber?
You'd loose your check, but it isn't serious science site either.

russ_watters

Mentor
Re: Re: Re: VSL book

Originally posted by wimms
bs. constant C is very first sentence of SR. its literally postulate. That the ideas to create SR came from empirical data is irrelevant.... And that it matches empirical data is the only reason its accepted.
I just looked it up. You're right. I stand corrected. It is a postulate. However, the fact that it is based on imperical evidence is to me very important. You say its the "only reason its accepted" and thats fine. Its a damn good reason.
You say these components do not exist. I'm not saying they do, I'm asking if the possibility exists that they might.
Certainly possibilities exist. Possibilites ALWAYS exist. But without any evidence to support the existence, "possibility" isn't enough to build a new theory or challenge an existing one.
. Is there a possible mechanism due which we observe C always as constant. Any theory that will answer that must explain why we observe C as a constant.
Thats your point, not mine, so you tell me. I'm sticking to the obvious answer: we observe C to be constant becaus C is constant.
Whole criteria for being theory is requirement to offer predictions that can falsify theory. I've never heard of empirical data about strings.
I know significantly less about string theory than I do about relativity. But this discusion is about relativity and relativity *IS* falsifiable.
Whats the bloody matter with you? What makes you say I'm discarding it? I've never said C is observable as VSL. I repeat: I'm ASKING if variations of C could manifest itself as some other phenomena.
The implications of the "yes" answer (if verified) that you appear to desire are that relativity and other major theories would need to be discarded. Its a loaded question. The answer is of course yes because of the word "could." Could I grow wings and fly? Yes, but its not likely.
then we must accept that meaning of distance must vary accordingly
...and it does.
Are you saying that c is same inside water, air, fiber?
YES. The principle of refraction is dependent on AVERAGE speed through a medium. The mechanism is that when light hits an atom, it gets absorbed and re-emitted. The delay associated with this causes a change in the APPARENT speed of light through that medium. When moving from one atom to another inside a medium (and anywhere else for that matter), light is traveling through a vacuum and travels at C.

Integral

Staff Emeritus
Gold Member
Russ,
You are doing an execellent job defending the correct positon, but as a ME it is clear that you have not been exposed to a full blown course in E&M.

Einstein's postulate of a constant c was NOT based on empirical evidence! Gads, people, at least make a minimum effort to study a bit of History of Science before you start talking! (Russ, this is not meant for you, but please listen!, or should I say read!)

In 1867 Clerk Maxwell expressed his set of equations in the form of the traveling wave equation. The velocity of the traveling wave, call it v, was expressed as v2= &epsilon;0&mu;0. When he computed the value of this quanity, The two contants, one geometric the other long known experimentally, the result was equal to the then current experimental value for the speed of light. This was the first solid bit of evidence that light was electomagnetic in nature.

This was a shocking discovery, primarly because it equated the speed of light to fundamental constants of the universe, the speed of light was a fundamental CONSTANT! This discovery created a rift in Physics which lasted until Einstein Published his Theory of Special Relativity.

Can you please make an effort to put a bit of historic perspective on this problem. Pretty much for the last half of the 19th century the world of Physics was forced to live with a c a fundamental constant. This did not fit into Newtonian Physics and many were not happy. To make matters worse, Michelson and Morley did an experiment which, rather then showing Maxwell to be wrong, VERIFIED the fact. The problem was called Maxwells Cundrum and many were simply waiting for Maxwell to find his error.

What it comes down to, is that for the last 150 yrs, mankind has known that the the speed of light is a fundamental constant. In the last 150 yrs the best minds known to man have been developing science and technoloy to degrees never dreamed possible. One of the keys to this sucess has been the understanding we have of ElectroMagnetism. This basic understanding started with Maxwell and a constant c. If you wish to change then simply turn off your computer because it does not, and cannot work without a constant c.

With this understanding you must understand why the main body of Phyiscs pretty much distains the chriping of the crackpots who doubt the constancy of c. It has withstood a centruy and a half of intense scrunity and it will continue to stand as a fundatmental constant.

My advise to the naysayers is to make an effort to understand the current state of knowledge, without the benifit of the current knowledge you are wasting your time, my time and everyones time who reads your posts.

With all that said I recently was looking at a book called VSL, varible speed light, where this reputable physicist is proposing a higher speed of light theory to explain the early expansion of the universe. Note that this would mean that the fundatment constants of the universe may be chaning with time. Very slowly of course, so we may not be able to detect it. I would not argue against such a theory but I will certianly argue against anyone who claims that the speed of light is different traveling to the left then to the right.

wimms

Originally posted by russ_watters
However, the fact that it is based on imperical evidence is to me very important. You say its the "only reason its accepted" and thats fine. Its a damn good reason.
Sure it is. Thats why its called theory not fancy idea. But notice how things went, first they measured c by approx means. People assumed ether existed and c depends on it (LET). Then Maxwell equations predicted that c is constant, and offered way to calculate c precisely. By then there were questions about invariance of c. Then MM made their experiment, and bummer. Then came SR to turn over the world.
Imo its no less important to notice that constant and limit of c was predicted before it was even possible to measure precisely. So it went in this order: predicted as possibility, then included into consistent theory, then confirmed with endless faultless demonstration.

Certainly possibilities exist. Possibilites ALWAYS exist. But without any evidence to support the existence, "possibility" isn't enough to build a new theory or challenge an existing one.
Thats interesting, because in other thread you went quite far to show that possibilities do NOT always exist. I'm not challeging existing SR. As to "possibility", if it exists to build a theory that explains "more" than existing ones, then this is "enough" to go for it. This is not to say that I offer some new theory, but to merely justify 'what if' thinking as an excercise.

Thats your point, not mine, so you tell me. I'm sticking to the obvious answer: we observe C to be constant becaus C is constant.
Russ, don't challenge me to offer consistent theory, you realise well that I'm not equipped to do that in form you'd ever accept as truth. I AM sticking with same answer as you if it comes to betting your last check.
But you still don't realise what I'm about. There is a difference between what we observe and what IS. Your positivist approach is nice, but it limits imagination. Lets for sake of argument say that what SR postulate really says, is that C will always be measured same in any equivalent inertial frame. This puts any potential variance of C outside SR if it is ever possible. Simply because inertial frames with different C are NOT equivalent. Laws of nature would be different. And this means manifestation of something else.
See, within realm of SR, variance of C isn't even meaningful question. But that doesn't mean that question itself is necessarily meaningless.

We can say from SR that inertial frames are equivalent only if C measures the same. See, we can compare frames only if we know how to convert them to equivalent form. And that implies time dilation, length dilation, energy. Thats the math of SR. It holds, and within domain of SR its bulletproof, even if C 'really' varied, over long time or over short time.

There are more assumptions under SR or any theory. For eg. assumption that all inertial frames ARE equivalent, that laws of nature are same in any. Its all nice and I'm not refuting these assumptions either. But with any of them you could play 'what if' and wonder if we'd be even capable of noticing if that wasn't strictly true from some imaginary absolute frame. Our whole construction of observable reality depends on what we consider comparable. My only point is, that we possibly wouldn't be able to detect fluctuations of such kind, simply because we consist of the very fluctuations that also offer us frame of reference. Frames with different timeflow are NOT equal until we transform them so that we can compare them with same clock rates. Distances are NOT equal until we transform frames to common measures.

The implications of the "yes" answer (if verified) that you appear to desire are that relativity and other major theories would need to be discarded. Its a loaded question.
NO. I do not agree that implications are what you think. Any theory has "Domain of Applicability". For SR, one of its components is postulate of const C, for variable C it simply wouldn't be applicable. This doesn't mean SR is wrong, it only means that variations of C are outside scope of SR. Its a loaded questions yes, but not in the sense you wish to imply.

Lets for a second consider what variance of C means. To even consider such thing, we need to imagine being separate from universe. But same happens when you imagine time dilation. To say it occurs we are forced to imagine timeflow here and timeflow there. But unless we imagine some absolute external frame, even such distinction isn't necessarily valid. Yet we do that. Same for distances and space. Somehow we imagine that there is some independant space inside which all frames are. But the very meaning of spatial distances depends on frames timeflow.

It occured to me, that perhaps you assume like Integral that I'm arguing C differing based on direction? Or that I propose FTL possibility or smth? No, what I'm trying to understand, is what is our reference ruler by which we could possibly detect variance of C, if any change in it causes change in laws, making frames not comparable. I'm thinking that we DON'T have such ruler. Any time we detect difference in frames, we observe it in some way that requires us to transform it to our reference measures. And that such difference would manifsest itself not as change in C, but perhaps as relativistic v of a frame, or somthing.

re: then we must accept that meaning of distance must vary accordingly
...and it does.
Exactly. And this means that rulers change. Now question is: what are we measuring, and with what rulers, if rulers themselves aren't absolute? The only answer is that relationship between the rulers is constant C. And that too with restriction to equivalent frames.

Look, by corollary from SR itself, if we have inertial frame, and right next to it another that happens to have different timeflow, then this difference transforms into space and velocity between them! Mere change of time relative to nearby frames is effectively equivalent to motion. Slowdown of time in spacepoint relative to surroundings is equivalent to contraction, increase of mass and latency for photon traversal if viewed from 'outside'. For observer 'inside', opposite is observed, expansion of the frame, and speedup of photon that leaves into surroundings.

YES. The principle of refraction is dependent on AVERAGE speed through a medium. The mechanism is that when light hits an atom, it gets absorbed and re-emitted. The delay associated with this causes a change in the APPARENT speed of light through that medium. When moving from one atom to another inside a medium (and anywhere else for that matter), light is traveling through a vacuum and travels at C.
Really? Where can I find a source to back this up? Anything I've seen claims c itself differs in medium.
Absorbtion of photon is energy dependent. Would photon with low enough energy get ever absorbed? Refraction angle can't be explained by particle behaviour. Either can't explain why light ray maintains direction of line or can't explain why it bends. Also, matter is sparse enough for photon pass it without ever hitting any atom. This means impulss sent to a medium must be measured to travel through it at anywhere between C in vacum and its slowest pass though the medium. If that were true it'd have devastating impact on communucation signals.

wimms

Originally posted by Integral
With this understanding you must understand why the main body of Phyiscs pretty much distains the chriping of the crackpots who doubt the constancy of c. It has withstood a centruy and a half of intense scrunity and it will continue to stand as a fundamental constant.
Right. C is observed constant. Length and time varies. The very dimensions of velocity.

My advise to the naysayers is to make an effort to understand the current state of knowledge,
I do make my sincere effort. Its damn frustrating to see that every thinking attempts of nonauthorty is bashed to a crackpot category. Yes, I'm not able to express myself as clear as you'd wish. I Can't express more clearly than I've already have: I DO respect SR. Thats why I'm ASKING, not making statements.

During this thread, I've came across something that perhaps better and with more authority talks about similar things: Double SR.
http://arxiv.org/abs/gr-qc/0012051

or even better, overview of VSL stuff by Joao Magueijo:
http://arxiv.org/abs/astro-ph/0305457

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Hurkyl

Staff Emeritus
Gold Member
Refraction angle can't be explained by particle behaviour.
A photon is a quantum particle, not a classical particle.

russ_watters

Mentor
Originally posted by Integral
Russ,
You are doing an execellent job defending the correct positon, but as a ME it is clear that you have not been exposed to a full blown course in E&M.
Heh, yeah or the history of physics. Thanks though.

It was always my understanding that until MM, it was believed that light traveled on the "ether" and therefore would vary. They were of that belief, weren't they? I thought they were surpised at the result of their experiment.

I did not however know the magnitude of the "rift" in the physics community at the time. The short history lesson often looks very different from the long one.

Really? Where can I find a source to back this up? re: refraction
Anywhwere you care to look, wimms. Any book or site that explains the mechanism and not just the usage of refraction. Start with google.

wimms

Originally posted by russ_watters
Anywhwere you care to look, wimms. Any book or site that explains the mechanism and not just the usage of refraction. Start with google.
Obviously, as I said, I did. Everywhere I look, they say c is lower in medium.

Actually, what confuses me is notion of absorption and reemitting with delay. This seems to imply pointparticles. But medium is complex sum of fields where there is no clear borders between particles and vacuum. Even if we say that retardation of light in such fields is only apparent slowdown of c, this doesn't say anything about reason vacuum itself has specific permittivity/permeability. Seems like saying that vacuum has anthropic reasons, and everything else gets lower speed due to complex tensions between the fields of particles.

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russ_watters

Mentor
Originally posted by wimms
Obviously, as I said, I did. Everywhere I look, they say c is lower in medium.
[?] [?] There is another thread on this board about it. You've posted in it. But could you post some links that you looked at that confirm your belief? I suspect the sites are all high school physics type sites that only talk about refraction in a Newtonian sense.

Like I said, google (type in "light refraction mechanism"). This is the first link:

When the wave impinges upon a particle of matter, the energy is absorbed and sets electrons within the atoms into vibrational motion. If the frequency of the electromagnetic wave does not match the resonant frequency of vibration of the electron, then the energy is reemitted in the form of an electromagnetic wave. This new electromagnetic wave has the same frequency as the original wave and it too will travel at a speed of c through the empty space between atoms. The newly emitted light wave continues to move through the interatomic space until it impinges upon a neighboring particle. The energy is absorbed by this new particle and sets the electrons of its atoms into vibration motion. And once more, if there is no match between the frequency of the electromagnetic wave and the resonant frequency of the electron, the energy is reemitted in the form of a new electromagnetic wave. The cycle of absorption and reemission continues as the energy is transported from particle to particle through the bulk of a medium. Every photon (bundle of electromagnetic energy) travels between the interatomic void at a speed of c; yet time delay involve in the process of being absorbed and reemitted by the atoms of the matter lowers the net speed of transport from one end of the medium to the other. Subsequently, the net speed of an electromagnetic wave in any medium is somewhat less than its speed in a vacuum - c (3 x 108 m/s).
http://www.glenbrook.k12.il.us/gbssci/phys/Class/refrn/u14l1d.html [Broken]

I guess this explains your problem with Relativity - you think the baseline assumption is wrong. It isn't.
Even if we say that retardation of light in such fields is only apparent slowdown of c, this doesn't say anything about reason vacuum itself has specific permittivity/permeability
Looks like another "why" question to me. But I'm not sure I'd use the same concepts in a vacuum that you'd apply to a medium. A vacuum isn't a medium per se.

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Mattius_

well i was actually referring to a book by joao magueijo titled 'faster than the speed of light'... it is an actual theory with substantial reasoning.

wimms

Originally posted by russ_watters
But could you post some links that you looked at that confirm your belief? I suspect the sites are all high school physics type sites that only talk about refraction in a Newtonian sense.
Well, of course I have seen such descriptions as you offer, but mostly in what I saw as school physics simplified texts.

http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/ltrans.html#c3
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elefie.html#c3

http://www.ldolphin.org/setterfield/vacuum.html

Like I said, google (type in "light refraction mechanism").
Yeah, and I find simplified explanations, like marching soldiers analogy in chapter before one you quoted.

I guess this explains your problem with Relativity - you think the baseline assumption is wrong. It isn't.
No. This C in matter issue isn't even related to my questions about R.
Again. how many times have I say that I have no problems with R and that I DO NOT think baseline assumption is WRONG. As Hurkyl and you have put it, if we can't observe it, then we need not be concerned with it.
Again, I raise a question, that perhaps the baseline assumption is right because we have no means to detect variance in C, as we have no other better reference for measures!
Would we notice change in standard of 1 meter, if ALL spatial distances changed in accord? No. SR predicts length dilation that observer in given frame would not notice. Thus, observer in inertial frame has different standards of measure without ability to notice that. All it can do is to compare his standards to standards in other frame, by applying SR transforms.
C, as a fundamental unit in existence is so deeply into any phenomena that any of its change would cause whole phenomena to get redefined.
I'm seeking to understand IF we could possibly detect change in C, accounting for all of the implications, or would all of the implications cause so coherent change in our frame that our observational means would be unable to notice. If possible, then what kind of phenomena would we notice when we compare our frame with other inertial frames?

Looks like another "why" question to me. But I'm not sure I'd use the same concepts in a vacuum that you'd apply to a medium. A vacuum isn't a medium per se.
I'm not sure why you see it as 'why' question. It is a point of analogy. Vacuum has fundamental constants that define c without presence of any matter. Light is EM, thus has to do with fields. Are you saying that space between matter particles is empty of EM fields? Are you saying that atoms take up specific volume with sharp boundaries separated by pure vacuum? That there is some specific distance between atoms instead of some probability waves?
As I understand, inside matter there are complex EM fields that interact with each other and photons, causing continuum-like changes in refraction and thus C. Maybe this is wrong, but I didn't make this up.

russ_watters

Mentor
Originally posted by wimms
Yeah, and I find simplified explanations, like marching soldiers analogy in chapter before one you quoted.
...which clearly don't say anything at all about the mechanism of refraction.
Maybe this is wrong...
Yes.

There really isn't anything else to say here. Either you choose to accept accepted physics or you don't. Its up to you.

wimms

Originally posted by russ_watters
There really isn't anything else to say here. Either you choose to accept accepted physics or you don't. Its up to you.
What kind of answer is that?
I asked questions, and you answer with .. this? Is it that you have no idea yourself, and the only thing you can do is to accuse in crackpotery, again?? Damn, this is so arrogant.
And it isn't even relevant to the main discussion, for which you can't also answer anything sensible other than crack-crack-crack as if every single blody question about SR means attack on it. Can't you really never get out of the box and explain to a layman why would we necessarily in any case notice change in C?

russ_watters

Mentor
Originally posted by wimms
Its the only way out of this cycle. We HAVE given you answers, you just refuse to accept them. There isn't anything more I can do for you.

wimms

Russ, you haven't given answers to my questions. You accused me in hell knows what, and have kept repeating what I already know.
You say I refuse to accept answers, thats bs. I accept perfectly all that you explain. You just don't. Perhaps you don't even understand the question. And thats because you keep accusing me in herecy. You don't seem to even understand what is meant by VSL. Its not additive v, but relativistic C, value of which varies on whatever, but not addition of motion v. More like in the book of VSL, but on very small scale and very short time. Best answer so far was Hurkyl's, that we don't bother with it. Yes I'm not happy because I want to understand what impact it would have if speed of light changed, very globally or very locally.

This question remains unclear to me, and its sad that you can't do me a favour explaining to me. You obviously imply that you could.

cytokinesis

Wimms, the thing is is that the speed of light in a vacuum just does not vary. It stays at c. Even if it varies, our measuring equipment would vary with it, and like Hurkyl(...I think) said, then we'd implement Occums razor and simply state that for all intents and purposes, c does not change, because even if it did, we wouldn't have any way to tell.

wimms

Originally posted by cytokinesis
Wimms, the thing is is that the speed of light in a vacuum just does not vary. It stays at c. Even if it varies, our measuring equipment would vary with it, and like Hurkyl(...I think) said, then we'd implement Occums razor and simply state that for all intents and purposes, c does not change, because even if it did, we wouldn't have any way to tell.
Thats pretty much my point, BUT, if you go further, and suppose that C varies in some 'area' of universe and not other, then, there must be detectable difference between the areas. What would it be? Suppose 2 extremes, 10 billion lightyears apart, and few hundred planck lengths apart. What should we observe and detect?

cytokinesis

I don't see how that'd either be possible, or really matter to us for our purposes, because in our corner of the universe the speed of light does not vary, so to speculate about it's variance is pointless for our purposes.

wimms

It has point. Change in C around our reference frame would cause us to perceive that other area differently. For eg, we could detect change in spatial distances, curvature of space. Maybe relative motion.

As to being pointless if unobservable, then there is just a thread about gravity waves, gravity field being defined as that which couples to spacetime. So they are searching for ways to detect gravity waves, or variance in something that very much defines all our measures, our very shape and dimensions. This reminds a 2D creatures on surface of a paper sheet trying hard to detect vibrations of the sheet by 2D measurements. Sure they won't succeed, but if they suspect existence of 3rd dimension, is their attempts pointless?

Albrecht

Originally posted by Hurkyl:
That's when we apply Occham's Razor. If the whole of spacetime is conspiring to make any variation in c unmeasurable, then we can get no wrong answers by presuming c does not vary in our theories.
This is by my understanding an improper use of Ockham's razor.

If we believe in the constancy of c in all inertial frames, then this believe is in fact not the easiest way in the advice of Ockham, that we should avoid unnecessary assumptions.

1. It is a definite consequence of the relativistic phenomena 'contraction' and 'dilation' that the measurement of the velocity of an object, having speed c, from a different frame of reference will yield the same result, even though the velocity is different in relation to the other frame. - It is a quite simple application of the Lorentz transformation to prove this.

2. The (so called 'geometrized') relativity theory of Einstein is not at all the simplest way to understand relativity. There are many persons who have studied physics, who have difficulties to understand the 4-dim. frame, where time and space are interrelated to each other in the given way. On the other hand, if it is assumed that there is a constant velocity c in exactly one reference frame (as stated by Lorentz/Poincare), the theory is simple enough so that most college students will be able to understand it.

3. At a different meaning of this point: the velocity of light is reduced in a gravitational field. So it is not constant everywhere. This is a very important fact because it is (according to Roman Sexl) the reason for the gravitational acceleration.

4. As we do not understand the reason why the velocity of light is constant, we do not know what may happen in other areas of the universe. But we know that we do not really understand the spatial development of the universe. So, something in our present physical understanding must definitely be wrong. This may also be the believe in the constancy of c in relation to the location within the universe. So also from this consideration we have to be open for a variable value of c.

And, apart from this: Professor Guenter Nimtz, Cologne, has made an experiment during which a signal was transmitted with a velocity greater than c. I have seen the experiment by my own eyes and it was a true superluminal transmission of information.

paultrr

VSL comes in a couple of different flavors, so to speak. There are some of us who accept variance if the vacuum state is altered. Generally of those in this camp some of us see only quantum effects and non-locality as generating a real change in C, in which case classical information transfer is always regular C limited and only Quantum information can transfer FTL. However, quantum information gives rise to classical information and may offer methods of varying the classical information faster also.

There are also members of the VSL camp that believe that C has altered over time in this Cosmos so that early own we may detect differences in the value of C as far as studying the information on space-time structure we gain from astronomy sources. Generally those of the accelerated expansion camp have held to C slowing down over time which makes them VSL and in light of the recent evidence from the MAP project the accelerated expansion issue seems rather upheld so some version of a variable C is at play.

Generally Smolin and some of the members of his own group are within the VSL camp and do hold to one aspect of this or another.

As for predictions in general, depending upon who's VSL model you follow the predictions can range simular to those found in standard inflationary models to some odd quantum scale effects where the cutoff on ultra-violet may be higher than standard theory has presupposed. There is also some speculation on the IR cutoff issue though those have never been as codified as the UV type.

The issue with certain experiments showing faster times by tunneling fits more within the quantum information camp. If you go back to the original wording of Einstein's paper in German it basically says that the speed of light is constant in the vacuum which GR tends to put some strong qualifications on what exactly that vacuum state is. In any case where the medium is altered either by natural effects or by artificial ones you are not dealing with a direct violation of relativity at all even if the speed of information transfer is higher or lower. Particles entering our atmosphere have long been known to travel faster in the atmosphere than photons do. Einstein in his time knew of this effect. Read SR. It only implies Lorentz invariance of the general type within the vacuum state.

The standard difference between those of us who follow VSL principles of the quantum informational type and regular VSL approaches is most of us tend to hold to Lorentz Invariance in ever modified vacuum state. That does not eliminate differences when you compare one vacuum state to another. In that case there will always be a difference in velocity. But when you alter the vacuum state then you can't directly compare the two.

Your's
Doctor Paul Karl Hoiland
A VSL Researcher who a bit back
was mentioned in connection with
Smolin in New Scientists.

paultrr

It is true that the subject about Alpha varying is not a settled one. However, the vacuum state during inflation is not the same vacuum state after inflation, nor is our present vacuum state the same as during the early part of the Big Bang itself. Also adding in some version of exotic energy also alters the vacuum state somewhat. Its the how that is more or less in debate.

Dr. Andrew Strominger of Harvard pointed out that Einstein himself modified relativity in 1915, when he brought gravity into the picture with his general theory of relativity. Special relativity, as the 1905 theory became known, is only strictly valid in flat space without gravity, Dr. Strominger said.

He added, "It is natural to think that Einstein's relativity will in some sense be violated by small corrections, just as Newton's theory of gravity has small corrections." These corrections did not make Newton wrong, he said, they just meant his theory was not always perfectly applicable. Likewise, relativity may give way to a more complete and accurate theory.

How relativity could break down, if it does, depends on how physics might act at the quantum gravity scale. Basically, untill that question is more or less answered the debate of this will still stand and the idea that light is not as constant as once thought will remain a possibility.

Most who support VSL, not all though, general believe relativity is correct under normal conditions. Some of us also believe that even when C alters it still remains Invariant within that specific frame. Some of these perfered reference frame ideas that have showed up in LANl and elsewhere have a ring of Newtonian ideas and tends to make some of us suspecious. I don't personally have a problem with the ZPF as a background, or even the few articles that have discussed the CMB as such. But when one tries invoking some version of an absolute space and time frame back into the equation then you run into the older Aether like frame.

Albrecht

The fundamental problem is that we do not have any idea which physical phenomenon causes the speed of light to have a specific value.

Also the relativity of Einstein merely uses this fact without understanding or explaining it. So we cannot do anything then to wait for a measurement which shows a deviation. Anything theoretical will most probably be guesswork.

Apart from this we should not forget that Einstein's relativity is a (so called) geometrized theory. Geometrization can be done with every physical theory. In most cases it provides an elegant mathematical presentation. But it does not tell about the physics behind it. The same is true for Einstein's relativity. Einstein has never explained why our physical world has relativity.

Nereid

Staff Emeritus
Gold Member
To what extent does a clear, well-accepted observation that alpha (the fine-structure constant) has varied, in cosmological time, require that c has also changed over cosmological time?

How theory-dependent is such an alpha-c connection?

paultrr

Actually VSL ideas do not always involve a change in Alpha. But if Alpha did change we would have a variance of C. The assumption based on some of those observations was that Alpha must have varied to get those results. This lead to the further assumption that if Alpha changed then C must have changed. But some models of VSL have C vary even though Alpha never changes. One such model has a varying scalar coupling where the vacuum's energy density has varied over time. One article on that, though I do not have the exact link this moment was done by Smolin and Magueijo.

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