Is VSL the Key to Interstellar Communication and the Fate of Humanity?

[Hurkyl]

Refraction angle can't be explained by particle behaviour.

A photon is a quantum particle, not a classical particle.

 

[russ_watters]

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.

 

[russ_watters]

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

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.

 

[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]

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]

Originally posted by wimms
What kind of answer is that? I asked questions, and you answer with .. this?

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, that's bs. I accept perfectly all that you explain. You just don't. Perhaps you don't even understand the question. And that's 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, until 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]

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.

 

[Nereid]

GLAST to test VSL?

At least two astronomers think it will be possible before 2010, to observe 'the frequency-dependent propagation of high-energy photons from GRBs' (strictly speaking, they feel that GLAST observations may be able to test quantum gravity, but the data may also show VSL). The link:
http://glast.gsfc.nasa.gov/science/...AST_GRBs_QG.pdf

A big thanks to Jeebus for his pointer to this

Earlier work, using EGRET and BATSE on Compton, as well as Earth-based TeV gamma ray observations, have produced a null result.

 

[hitssquad]

Redshift and the speed of light

Originally posted by russ_watters
Everything we know about light tells us its speed is constant. Does anyone want to present some ACTUAL EVIDENCE that it is not constant?

Redshift.



-Chris

 

[hitssquad]

The relativityof relativity

Originally posted by paultrr
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.

So it's relative?



-Chris

 

[russ_watters]

Originally posted by hitssquad
Redshift.

Yikes, didgging up a dinosaur. No, redshift is not evidence of VSL.

Yes, I understand you could model it that way, but since that model doesn't fit with other observations of the speed of light, you have to directly measure a vsl before you can use it as a model for cosmological redshift.

 

[plum]

The theory of VSL dictated that professeur M Majueieojioue would transport his body to another region of the universe and make contact with aliens who would tell him that the human species is doomed to an eternal hell of evil robotic takeovers of the basic biohumanic chain of living that keeps us all alive.