Doesn't light's constant speed dictate an 'ether'?

[russ_watters]

Russ - if you are saying that time dilation is real - fine - is that your unambiguous conclusion. If it is, it is in conflict with many relativists. I don't have a problem with it - but most relativists do - And from my previous discussions with janus I got the distinct impression that he regarded it as apparent.

Set two clocks on Earth to the same time. Launch one into orbit for a few days, weeks, months, years. Return the traveling clock to earth. Compare the readings. The readings are now different. That is real.

I would very much like to see a citation of anyone who accepts relativity who doesn't accept this (seems like an oxymoron).

Apparently Einstein did not regard it as real because he introduced the notion of the acceleration at turn around to justify why the clocks could have different times when they were brought back together - an entirely unnecesary gimmick if in fact the clock attached to the traveling twin was already falling behind the stay-at-home clock before it begin its turn around.

No, its necessary to take into account the acceleration at turn around because it changes the inertial reference frame of that clock. That's the whole point of relativity (and the twins paradox) that you are calling "unnecessary."

it's me, the ignoramus again...if i can hijack this monster I've created for a minute...

Its your thread, you can do what you want. Hopefully, Tom had you covered there...

 

[Janus]

Russ - if you are saying that time dilation is real - fine - is that your unambiguous conclusion. If it is, it is in conflict with many relativists. I don't have a problem with it - but most relativists do - And from my previous discussions with janus I got the distinct impression that he regarded it as apparent. Apparently Einstein did not regard it as real because he introduced the notion of the acceleration at turn around to justify why the clocks could have different times when they were brought back together - an entirely unnecesary gimmick if in fact the clock attached to the traveling twin was already falling behind the stay-at-home clock before it begin its turn around.

I never meant to give the impression that I regarded time dilation as apparent. I consider it, as well as length contraction, as very real, as do most relativists.

When triplet 1 says that x amount of time passed for triplet 2 because time ran slower for triplet 2, that is real. When triplet 2 says that x amount of time passed for him because the distance separating him and triplet 1 is shorter, that is also real. Neither of these realities is any real than the other or has precedence, and there is no other level of reality that exists and has precedence over them. They are as real as real gets.

Relativity does not say that time and space appear differently in different frames of reference, but that time and space are different in different frames of reference.

 

[yogi]

Nereid - the inflow theory regards gravitational attraction as consequent to spatial inflow into masses - if space is substantive (and I don't mean that it is made of particles that have mass) then the theory assumes that matter absorbes space - so in essence space flows radially inwardly and its velocity at every point exactly corresponds to the escape velocity at the radius where the force is measured - other masses are carred along by the inflow and the force required to hold them at the same radial distance from the attraction corresponds to gravity - the equations lead to the same force field as GR . The best thing in its favor is that it nicely ties time dilation in SR with Time dilation in GR - that is - if you calculate what the clock rate should be in a frame that moves at velocity v relative to the Earth for example, this corresponds to the clock rate that corresponds to the same altitude for a clock in the Earth's G field. Tom Martin has a number of articles posted on the internet which give a mathematical description of the theory. Tom also has suggested several test which would show whether it makes better predictions than GR in the situation where the G field is balanced between the Earth and the moon. Having said on this - don't ask me to defend it .. my personal feeling is that it is enlightening - and it may lead to something - but I don't have any better feeling about why mass sucks in space than understanding how or why mass bends space.

 

[yogi]

Janus - I think we have a problem in semantics - the word "real" The question posed is" What does the pion clock read in the frame of the pion when it reaches alpha and decays vs what does the Earth clock read when the pion reaches alpha and decays" - it is not a question of what the Earth based twin interprets as the rate at which time passes in the other twins frame - that is a subjective reality. If the two clocks have logged different times when the event is ended (the pion reaches alpha and decays)
then time slippage is real - that is the reality to which my thought experiment was directed -- and if the two clocks have in fact logged different times when the decay takes place - how can it be argued that acceleration and frame changing is needed - as Russ asserts. If the two clocks run at different rates - there is no paradox - but there is an intrinsic asymmetry from the start --- and that obviates the need for any further speculation re changing frames - acceleration - passing off information etc

 

[yogi]

Janus - again - your comment with regard to the reality of the contraction indicates to me that you are using the word "real" but what you describe is apparent because it always entails observations from one frame to the other. Real length contraction properly belongs in Lorentz Ether Theory - and as you well know, the primary reason why the ether theory was suspect is because it required molecules, atoms, electron wave lengths, etc, whatever, to all shrink to fit the contraction hypothesis. The big appeal of SR was that it did not require ad hoc propositions that depended upon mechanical dynamics. If a high spped particle could traverse the universe in a short amount of time, - this doesn't mean the universe has physically shrunk. What is measured by the high speed particle is not the "real" size of the universe - it may appear to be smaller to the particle - and you can even say that the shorter travel distance appears "real" to the photon - but the operative word is "appears" , not "real"

 

[russ_watters]

I never meant to give the impression that I regarded time dilation as apparent. I consider it, as well as length contraction, as very real, as do most relativists.

Ugh, please don't call yourself that. You're a scientist. "Relativist" (like "evolutionist") is a label made up by non-scientists to invoke comparisons to religious beliefs.

Yes, yogi - the problem here is partially semantic. It appears that you don't like the word "real." We've explained it several times and it seems you just plain don't like it and don't want to accept it. Will the dictionary definition help? http://dictionary.reference.com/search?q=real

1. Being or occurring in fact or actuality; having verifiable existence: real objects; a real illness.

You're bending the definitions of "real" and "apparent" because you don't like the fact that the phenomena that Relativity discuses are physically real. By saying the size of the universe (for example) that we measure is only "apparent," you imply that there is another size to the universe that is "real." There is not. No, the universe does not change size when measured by someone else, it is that size to someone else.

Maybe you don't like the idea that something can be two (or an infinite number) of different sizes at the same time. It doesn't make sense in traditional logic. I don't know what to tell you other than whether it makes sense in your version of logic or not doesn't matter. The universe doesn't have to conform to your wishes, it is what it is.

You do have a lot of company. A lot of people, even good scientists (even Einstein himself) have fallen into the trap of trying to set up the universe the way they want it and not the way it actually is.

 

[Janus]

To use an analogy.

Would you consider the kinetic energy of a bullet fired from a gun as real? (I'm sure you would if you were standing in its path.) But an object's kinetic energy is entirely dependent on on its relative velocity. To an ant riding on the bullet, its KE would be zero, To someone else moving relative to you it might be more or less. Does the fact that the KE is different for different observers make the KE only apparent to these observers and not real? When the bullet hits you does it only seem to carry a whallop?

Likewise, time and space are dependant on relative velocity, and the fact that they are different for different frames of reference does not make them any less real.

 

[yogi]

Janus - I see nothing negative in calling yourself a relativist - you have consistently presented the traditional interpretation of relativity on these boards - and I have yet to see you depricate others who have different views. I am now pondering your kinetic energy analogy - and will have something to say a little later - but the wife is calling me that its time to watch the Apprentice,. More later.

 

[yogi]

Back to janus - Energy, whether it be kinetic or potential, is not substantive in per se - it is a characteristic property of the relative-ness of two differences - in the case of potential energy, we can define the zero for example at the Earth's surface - and make measurements of the gravitation potential referred thereto - the same is true for kinetic energy - it can only have meaning with reference to something with respect to which it is moving - it is not something absolute - it is conceptual -- a property whose magnitude is defined by reference to something else. In the case of the universe, we can consider that total energy is always zero if we pick an initial negative potential that will cancel all the positive energy.

So yes - if you say there is a real energy difference between two moving bodies - that would be a correct statement - but I don't see how it can be said that either one has a real energy assocated with it. In the case I have been trying to make - we would say that a clock at rest with the high speed particle has a real (proper time) associated with it - it is not relative to anything and it goes on and ticks away at the same speed irrespective of the velocity of the particle. And the clock in the Earth frame measures the proper time for the event, and this is a real time that transpires whether or not high speed particles are traveling by or not. These two times I call real - there is a relative difference between the rate at which the two clocks run - I calal that real time dilation - but unlike the energy analogy, these two times exist independent of any interaction or experiment - contrary wise energy only has meaning where there is some reference by which it is measured.

 

[Nereid]

An answer to a simple question would be appreciated

yogi, I've asked this of you at least twice, but not seen any reply. May I ask again?

Thanks yogi; this is partly why I used the words 'specific' and 'unambiguously'

If I can make a comparison with another area of physics: Alain Aspect performed an experiment to test Bell's Theorem. Specific predictions from competing theories were unambiguously different; Aspect's result was consistent with one theory (and subsequently other researchers have confirmed and extended Aspect's results).

What comparable examples can the 'ether' proponents give?

Do you have a list of observational/experimental failures of SR or GR?

 

[yogi]

HI Nereid - yes - I know you have asked this question more than once - I apologize for not responding to it. To cite the several experimental results where some form of ether theory is more efficacious than SR would require a lot of explaining and the entire topic here would become a proliferating debate. Let may say first I am not an etherist in same sense as a Lorentz etherest - I have never been able to accept the idea of actual physical contraction of material objects - but I have reached some tenative conclusions of an aethereal dynamic - that space whatever it is, behaves as though it can move, and that motion with respect to it is not meaningless as posited by SR. Einstein ultimately rejected Mach's idea of distant matter being the casue of inertial reaction...in favor of a local property of space. I believe that is correct. The sagnac experiment can be explained with SR, GR or classically in terms of an ether - which is better is the cause of much debate. The anisotrophy of the CBR and the diurnal variation in the anisotropy strongly support the notion that the Earth's absolute speed with respect to some cosmic ethereal rest frame can be detected - this is in conflict with Einstein's fundamental premise upon which the second postulate is based (you might look-up some of the derivations put forth by Selleri as to how SR would need to be modified in connection therewith). The notion of a space in tension is supportive of the idea of a medium that admits of transverse electromagnetic wave propagations: And in connection with my posts above - if time dilation is real, there must be a physical reason for that result - SR does not propose any mechanism - but, it cannot be said that an ether is absolutely essential for the explanation - it simply simplifies the twin and triplet problems so there is not even an apparent illusion of a paradox - my own special interest has to do with the fact that expansion creates certain properties which predict the velocity of light, the value of the gravitational constant, and some other things which are off the subject. These consequences cannot exist if space is static void - so for me some form of dynamic ether is essential - but I am not an Einstien critic - It is to hs credit that he continually re-evaluated his contributions in the light of new data. I hope that sort of answers your query as to why I believe there is reason to continue one's thinking - lest we do not fall into the trap of accepting all we are taught as absolute truth - when that happens we will put an unjustified burden upon theoritical work at the forefront of physical research.

 

[russ_watters]

HI Nereid - yes - I know you have asked this question more than once - I apologize for not responding to it. To cite the several experimental results where some form of ether theory is more efficacious than SR would require a lot of explaining and the entire topic here would become a proliferating debate...

Translation: you know of no such observational/experimental failures of SR/GR.

The sagnac experiment can be explained with SR, GR or classically in terms of an ether - which is better is the cause of much debate.

No, which is better is determined by following the scientific method. The scientific method is clear on this point.

my own special interest has to do with the fact that expansion creates certain properties which predict the velocity of light, the value of the gravitational constant, and some other things which are off the subject. These consequences cannot exist if space is static void - so for me some form of dynamic ether is essential.

That is correct, but Relativity does not say space is a static void. There is no issue there.

 

[yogi]

Hi Russ - perhaps I can best summarize my view with regard to the special theory is that it describes a surface treatment of a deeper reality - it works for the same reason that abreviations work to convey an idea - the relativist (you will pardon the expression) can take solice in the fact that the short hand formulations are not going to be vitiated because they are exactly that - they are a proper mathematical representation that is derived by fiat (two postulates) which in actuality describes an underlying physical truth, but not yet discovered. As you point out, relativity doesn't assert anything about the void - being silent on the subject - we are left with a correlation problem - to conform the underlying physics so that the relativistic transforms are in agreement therewith (sort of a correspondence principle to borrow an idea from Bohr).

 

[billy_boy_999]

this might seem facile or naive, but its seems that if relativists (pardon) accept that the void is not essentially empty and etherists (pardon again) accept that there is no classical 'ether' then there really is nothing but semantics to argue...we all see that SR, GR make good predictions, and we also see that SR, GR are not complete 'unified' theories of physics and there must be something to add to it, or some new light to see it in...where is the argument?

i don't think anyone has made a good scientific argument to support a comprehensive ether theory...but then again i don't think that was the point, was it? 'ether' seems to be a valid and potentially significant tool for theoretical speculation...

 

[yogi]

Billy Boy - I would say that is a very good observation -

 

[jdavel]

bill boy said: "this might seem facile or naive..."

Yes it does!

"if relativists (pardon) accept that the void is not essentially empty"

I think I'm in the group you call relativists, so please explain what you mean by "the void" and what it means if I accept that it "is not essentially empty"

And what is " a classical ether"?

What is "a conmprehensive ether theory"?

Whether I'd agree with your statement that "'ether' seems to be a valid and potentially significant tool for theoretical speculation..." depends on your definition of ether, if you have one.

In short, since your post is so full of terminology that's either not defined in physics or is not defined the way you seem to be using it, the physics content of your post is negligible. The great progress in physics that began 400 years ago, began because people who called themselves physicists stopped talking this way and started ignoring people who didn't.

 

[billy_boy_999]

jdavel - if my terminology is unscientific or difficult to understand i apologize...

"the void" refers to the vacuum

the proposition that the vacuum "is not essentially empty" refers to the fact that there seem to be factors of permeability and permittivity that mean it is not a physically empty "void" - there seem to be physical properties of the quantum vacuum that cannot be discarded...as well it is "not static" (which may or may not be relevant)...

"classical ether" - i was referring to something like local-ether, or particulate ether...i admit to not understanding the complexities of 19th century ether theory...is this something close to a decent definition of "classical ether"...?

"a comprehensive ether theory" - a complete field theory that makes firm predictions (as Nereid has wisely suggested), especially ones that differ from SR or GR (Special Relativity or General Relativity)

Whether I'd agree with your statement that "'ether' seems to be a valid and potentially significant tool for theoretical speculation..." depends on your definition of ether, if you have one.

that is a bit like saying, it may be a valid area for theoretical speculation if your theory is good...which in a way is quite fair enough...but i think it is useful to draw a line between "theory" and "speculation"...surely you're not condemning "speculation" in theoretical physics?

on second thought, i think this argument is not really so much about semantics as much as it is about this physics forum - what is this forum for? fact or speculation? or more specifically, if an admitted ignoramus asks a question is it wise to answer only with fact? or is it good to add speculation?

i think it is good and edifying to add speculation because it shows the limit of current facts - where current knowledge stops...but then on this it is perhaps best to ask the ignoramus...

 

[Nereid]

What if that something, that aether/ether is distance itself. Distance gives you the ability to have dimension. Therefor that ether IS distance
here it is in math form
D=E(t)
Distance Energy Time respectively

(time is rate of time passage, NOT measuring from a starting point)

Can you account for the results from the various MMx (Michelson-Morley experiments) using this idea? Show us how!

 

[jdavel]

Can you account for the results from the various MMx (Michelson-Morley experiments) using this idea? Show us how!

Nereid,

In this thread (and most others here on SR) theories don't really have to account for any experimental result. Theories just are. Questioning the value of proposing theories that might be (even if they don't account for anything) is thought by most people still posting in these threads to be proof of a severely closed mind. So watch yourself!

The best thing to do is say something like "What if the ether is really the flow of time through the classical void (of course, Lorentz transformed), and the one-way premittivity of spacetime is just the essence of this flow, proving that the speed of light isn't constant?" Then sit back and wait for somebody to say, "That's a good point."

 

[selfAdjoint]

Theories that don't accept the discipline of comparison to reality are usually moved to the Theory Development board. They can be as righteous as they want there without confusing newbies.

 

[jdavel]

selfadjoint said: "Theories that don't accept the discipline of comparison to reality are usually moved to the Theory Development board. They can be as righteous as they want there without confusing newbies."

I know that's how it's supposed to work, but it's almost impossible to do that. A thread like this one that begins with a legitimate question about a well established theory, "Doesn't light's constant speed dictate an ether?" rapidly becomes cluttered with exchanges like the following:

post #3

The free space velocity of light as determined by Maxwell depends upon the permeability and permittivity of the vacuum void - so in this sense, there is a medium - give it whatever limitations you will. Moreover, if you consider space as being in tension (e.g. as would be the case in a false vacuum under any of the ongoing inflationary theories), then you can justify, at least in principle, how this spatial structure can support a transverse wave.

post #4 (from the originator of the thread)
very interesting, thank you :)

And there are more; #13 and #14 are a real doozy!

But there are also legitimate efforts to answer the original question within the bounds of the currently accepted theory, SR. I don't see all this getting sorted out to the appropriate board, nor do I think it's reasonable to expect anyone to do it. Any confusion that this hodgepodge of posts causes is part of the price we pay for a democratic internet.

 

[Nereid]

Nereid,

In this thread (and most others here on SR) theories don't really have to account for any experimental result. Theories just are. Questioning the value of proposing theories that might be (even if they don't account for anything) is thought by most people still posting in these threads to be proof of a severely closed mind. So watch yourself!

The best thing to do is say something like "What if the ether is really the flow of time through the classical void (of course, Lorentz transformed), and the one-way premittivity of spacetime is just the essence of this flow, proving that the speed of light isn't constant?" Then sit back and wait for somebody to say, "That's a good point."

au contraire mon ami! I beg to differ. If it's in the "Special and General Relativity" sub-forum, I do expect that all posters can expect questions about experimental testing :tongue: If nothing else, I have a reputation to protect!

Of course, it's perfectly OK for the answer to come back as "you know Nereid, I just haven't got around to working out anything like that yet" or "this theory should have results that are identical to those predicted by GR".

In the Theory Development sub-forum, expectations may be quite different (though I may seek to further build my reputation as being obsessed with matching observations and experiments, testability and tests )

 

[Nereid]

HI Nereid - yes - I know you have asked this question more than once - I apologize for not responding to it. To cite the several experimental results where some form of ether theory is more efficacious than SR would require a lot of explaining and the entire topic here would become a proliferating debate. Let may say first I am not an etherist in same sense as a Lorentz etherest - I have never been able to accept the idea of actual physical contraction of material objects - but I have reached some tenative conclusions of an aethereal dynamic - that space whatever it is, behaves as though it can move, and that motion with respect to it is not meaningless as posited by SR. Einstein ultimately rejected Mach's idea of distant matter being the casue of inertial reaction...in favor of a local property of space. I believe that is correct. The sagnac experiment can be explained with SR, GR or classically in terms of an ether - which is better is the cause of much debate. The anisotrophy of the CBR and the diurnal variation in the anisotropy strongly support the notion that the Earth's absolute speed with respect to some cosmic ethereal rest frame can be detected - this is in conflict with Einstein's fundamental premise upon which the second postulate is based (you might look-up some of the derivations put forth by Selleri as to how SR would need to be modified in connection therewith). The notion of a space in tension is supportive of the idea of a medium that admits of transverse electromagnetic wave propagations: And in connection with my posts above - if time dilation is real, there must be a physical reason for that result - SR does not propose any mechanism - but, it cannot be said that an ether is absolutely essential for the explanation - it simply simplifies the twin and triplet problems so there is not even an apparent illusion of a paradox - my own special interest has to do with the fact that expansion creates certain properties which predict the velocity of light, the value of the gravitational constant, and some other things which are off the subject. These consequences cannot exist if space is static void - so for me some form of dynamic ether is essential - but I am not an Einstien critic - It is to hs credit that he continually re-evaluated his contributions in the light of new data. I hope that sort of answers your query as to why I believe there is reason to continue one's thinking - lest we do not fall into the trap of accepting all we are taught as absolute truth - when that happens we will put an unjustified burden upon theoritical work at the forefront of physical research.

Thanks yogi.

Selleri = http://www.tlc.unipr.it/selleri/selleri.html

If you've seen the veritable cottage industries that've sprung up around inflation and dark energy (to pick just two examples ), you'd be quite heartened about how far we are from falling into the kind of bear trap you describe.

Do you know of any site where experimental results are discussed in terms of some form of ether theory?

Is any PF member up to starting a new thread on how or why some form of ether theory "is more efficacious than SR" when it comes to explaining experimental results? I'm particularly interested in which particular experiments would be best, for this purpose.

 

[yogi]

The original question posed related to the properties of an ether as being determinative of the propagation velocity - any posts that discussed the properties of the ether would therefore be directly in point. In post #88, the units are not correct -and therefore post 89 properly asks a further question. Apparently some of the members are of the opinion that there is only one way to answer a question about the ether and that is to jam the standard SR dogma down the throat of every inquirer - if these self appointed experts were a little more knowledgeable about the subject they wouyld know that all the so called proofs of SR also totally validate Lorentz Ether Theory, Inflow Theory and local ether theory. A few of us feel it is necessary that persons who make legitimate inquiries be offered the opportunity to ponder alternatives - this isn't a Church forum founded upon uncompromising indoctrination. I would agree that unfounded theories that violate fundamental physics principles would not be appropriate - but anyone who condemns mentioning still viable alternatives that were embraced by such great thinkers as Lorentz, Dirac, Michelson, and even Einstien to some degree, needs a lesson in tolerance.

 

[Nereid]

yogi: "... all the so called proofs of SR also totally validate Lorentz Ether Theory, Inflow Theory and local ether theory."

I didn't know that! Which websites would you recommend to the interested reader?

Apart from one reference to a "Lorentz's twice-extended theory" (by a 'Martin Miller', who's since left PF), in the context of describing how the GPS system works, I've not seen any statements about the extent to which any alternatives to SR or GR would match experiments or observations. Thanks yogi.

How does "Lorentz's twice-extended theory" relate to the three theories you mention?

Just for my curiousity, if you put anyone of these three theories (or some combination) into QM, do you get a theory which is indistinguishable from QED (in terms of predictions)?

 

[yogi]

Hi Nereid - I have a collection of about 100 such sites that I have copied into folders - some are worthless as the authors are so one sided in the criticism of SR that their thinking is muddled. Again, I do not want to get into the position of defending different theories because I myself am still looking for something physical that conforms with SR. I think what can be said is that, in some experiments, some theories come off better than others in explaining for example Sagnac, GPS corrections, Hafele and Keating, Michaelson-Gale, For a starting point - You can search Google for papers by Tom Martin (Tom is very competent from a mathematical perspective and has proposed some interesting tests that could help validate GR or discredit it ) Several papers by Selleri you apparently already have probably read, R Ron Hatch (about 4 internet papers) has been a consultant on GPS and takes the view that the Earth centered reference frame is consistent with ether theory but not SR. There is an interesting paper by Francisco J. Muller regarding SR reciprocity vs Lorentz theory.
Anyway, if you want more send me a private email and i would be glad to provide you with references to what I have

Yogi

 

[jdavel]

yogi said: "The original question posed related to the properties of an ether as being determinative of the propagation velocity..."

That's not true. The original post asked whether the assumption of constant light speed (the basis of SR) leads to the conclusion that there must be an ether. In the body of the post, the point was made that if light speed isn't constant relative to the source, then it must be constant relative to a medium, that is, the ether. In the very next post Dr Matrix cleared this up, by saying that, according to SR, light speed is constant relative, not to the source and not to any medium, but to the observer. So, constant light speed (as assumed by SR) does not dictate an ether. Question answered. Case closed.

Then you launched your defense of some version of an ether being CONSISTENT with observations of constant light speed. If the question had been, "Is the existence of an ether consistent with observations of constant light speed?" your posts would have been relevant. But the question was "Isn't the absence of an ether inconsistent with constant light speed?" to which your posts have been irrelevant.

Every time the word "ether" pops up, you use the opportunity, to justify the possibility of its existence even if that justification is irrelevant to the thread.

So who is it that's really trying to jam their dogma down the throat of every inquirer?

 

[yogi]

Nereid -- re QED - I have not seen an application of any of the theories in that regard - the statement is usually made that GR is not consistent with QM - but I don't know if that is correct - seems that it is quantum field theory that is inconsistent - I have the same problem with QFT as I do QED - that the graviton and virtual photon idea is useful as a calculating tool, but maybe these radiating particle theories do not conform to reality. Here again, an idea gets morphed into physics and after a while it becomes sacrosanct - QED works because it is simply a disguised version of perturbation theory which was already known to be an effective procedure for determining the second order anomaly in the gyromagnetic ratio.

The twice amended Lorentz Ether Theory incorporated time dilation as a reality - sounds terribly ad hoc - and it was. This is the present version of the ether theory that is consistent with SR. If you have the first edition of Spacetime Physics by Taylor and Wheeler, there is a historical note on page ____ where the authors state that there were three theories at the time Kennedy and Throndyke performed their experiment using an interferometer with different length arms. The null result discredited the original ether theory predicated up contraction alone - but it left in tac SR and the modified Lorentz theory that included time dilation. This is an example of where both theories predict a null result - and still do (sorry I can't put my hands on the book now, so the page # is left blank)

 

[yogi]

djavel - Quote: In the very next post Dr Matrix cleared this up, by saying that, according to SR, light speed is constant relative, not to the source and not to any medium, but to the observer. So, constant light speed (as assumed by SR) does not dictate an ether. Question answered. Case closed.

You confuse what is measured with what Maxwell originally derived (non-Lorentz Invariant equations). Even assuming arguendo, that Einstein's hypothesis that the one way velocity of light will be measured as constant (a postulate much in dispute), this does not actually change the "not understood physical mechanism" that determine free space propagation velocity. Measurements made in two relatively moving inertial frames attempting to ascertain the one way velocity of light would, according to the dictates of SR, both measure it to be c (as per DR Matix) - but both measurements would be subjective, each depending upon a different time dilation and/or length contraction in order to preserve the invariance of the interval - Relativity does not speak to the question of what determines the velocity of light - that is why the brief answer you assert to be the only answer misleading.

 

[jdavel]

yogi,

I can't believe you don't understand this point. It doesn't depend on the speed of light being constant. Maybe it is, maybe it isn't.

But the question was: Doesn't the ASSUMPTION of c being constant, force you to conclude that there is an ether? DrMatrix said the ASSUMPTION is that c is constant relative to any observer, so there is no need for an ether. He didn't say there is proof that c is constant relative to any observer. And he didn't say that if c is constant relative to any observer that there can't be an ether. All he said was that it's possible for c to be constant even without an ether. And that was THE answer to the question.

Your posts were answers to other questions, such as: Have we proven that c is constant? Have we proven there is no ether? When somebody asks one of those questions, your posts will be relevant. In this thread, they weren't

 

[billy_boy_999]

Your posts were answers to other questions, such as: Have we proven that c is constant? Have we proven there is no ether? When somebody asks one of those questions, your posts will be relevant. In this thread, they weren't

forgive me, but i think those questions were obviously implied...the more thoroughly we can explore the subject the better, right? jdavel, your suggestion that these things are irrelevant (and your posts delineating the boundaries of relevancy) i find pedantic...are you suggesting that the author of the question was ONLY interested in a short, discrete, yes or no answer to this very conjectural question?

for the record i will ask, posthumously: Have we proven that c is constant? Have we proven there is no ether? and, does anyone have anything relevant to say about ether theory? (again, i thought these were implied, not just in the original question but in the follow-ups)

as far as speculations on 'ether' being limited to the theory development forum - i think nereid is wise to let them stay where they are...are SR + GR antithetic to speculation on their own theoretical limitations?

 

[jdavel]

billy boy 999 asked: "are you suggesting that the author of the question was ONLY interested in a short, discrete, yes or no answer to this very conjectural question?"

Of course not. And you didn't get one. You asked about the implications of a well established and well accepted theory of physics. You got an explanation, of the physics behind the answer to your question from someone who understands the theory. And you got an answer, which was no. This is how well established theories in physics work. You don't have to debate their implications forever.

No offense, but the rest of your post: "sound waves wouldn't exist without the 'ether' of air and so you can say that the air is the only thing that slows down sound waves...what slows down light waves? or is it something in the energy of radiation itself? even so, it is slowed, it must be slowed, or a fast body would give off fast light..." shows pretty clearly that you know very little about physics. Your interest in mulling over the validity of a theory that's been accepted by the vast majority of physicists for nearly a hundred is typical of people who think this theory is interesting but don't really understand it. And niether you nor anyone else is going to learn the theory from posts like yogi's. He may understand the theory, but his objective is not to explain it, but to raise doubts about it.

There is a place on this board for raising and discussing doubts about and alternatives to well established theories. It's the Theory Development sub forum.

There should also be a place for people who want to understand relativity, and have it explained to them by people who already do and who are interested in explaining it. And those threads shouldn't be hijacked by posters whose agendas are not to explain but simply to raise doubts.

This thread has become ridiculous, and it should be closed. At any rate I have said all I intended to on it.

 

[chroot]

jdavel,

I'll report the post, and let the appropriate mentors deal with it, if they choose to.

- Warren

 

[yogi]

Billy Boy -Questions about SR sometimes provoke sensitivities - anyway - your question about the proving the constancy of light velocity is likewise the subject of much debate - originally thought to be necessary to explain the MMx experiment (which was an over and back set up) that failed to detect the Earth's motion relative to a putative ether. This was an interference experiment - recently on these boards the question was raised as to whether interference techniques really detect motion when both transmitter and receiver are comoving in the same frame (theoretically, there can be no Doppler shift and consequently no detectable fringe shift). So that observation raises serious questions about the fundamental bases upon which Einstein asserted that light velocity would be measured as constant. Then there is the question of, even if the over and back velocity is constant as per MMx - is the one-way velocity constant? - this involves sync problems with more than one clock -and there is debate about whether the one way velocity of light can be effectively measured. Finally, since GPS systems appear to work using the one way velocity of em waves - it is argued that this proves the validity of Einsteins postulate - but that also has a snag in view of the Local Ether Theory - which proposes that the G field of the Earth conditions local space making light locally isotropic.

All these different theories are being brandied about on the net. You can have a truly delightful time thrashing though all that is published - keeping in mind how lucky we are to have these fascinating unsolved mysteries to ponder - how boring the world would be if everything had already been solved.

 

[brookstimtimtim]

Aether or no aether. If string theory proves true then the strings could be considered aether. If you look at quantum mechanics then with quantum particles everywhere you could consider them aether too, So the only thing that has changed is the name. I personally think that the fact "c" is constant for all observers supports this. Why do you ask, because if atomic motion slows down (time slows) as you reach "c" then there must be something there to cause that. If you abandon aether then you are saying like no other wave known on Earth light can travel through nothing because it's magic. So my question is why are you so quick to say light is magic, then saying "something is there we just don't know what it is or how it works"? If you do not agree then you tell me why light is constant for all observers, I don't want a stupid math problem that says ,it just is, I want to know what causes time to slow down, and if you don't know, then why are you so quick to say there is no aether? Nasa only recently found that dark matter may be true. So just because they have not found it yet, doesn't mean that they will never find it. If you want all this put in a simpler way, What is stopping light from traveling any faster than it does and what slows time if space is truly nothing? If space is nothing, than the answer is nothing. It makes you say "hummmmmm". This is why so many people with common sense is looking for aether, it is aether or magic.