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

[billy_boy_999]

firstly, i'm an ignoramus

secondly, doesn't the fact that lights speed cannot be affected by the speed of a body that emits it suggest the existence of an ether? 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...

help me out?

[DrMatrix]

You'd think so, wouldn't you?

Here is what Special Relativity supposes:
Assume you are at rest. I'm in a rocket ship coasting past you. Just as I pass, you turn on a light. According to your measurements, the light travels away from you at c. The strange thing is if I measure how fast light is going I observe that light travels at c relative to me.

Where is the aether?

[yogi]

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. While ether theories are out of vogue, they are not dead - and the adherents are not all crackpots - there appear to be more ether based articles coming out of the universities - contrary to common opinion, SR did not disprove the existence of an ether.

[billy_boy_999]

very interesting, thank you :)

[TeV]

- contrary to common opinion, SR did not disprove the existence of an ether.SR did disprove the existance of CLASSICAL ether*.In modern physics it is more convinient to talk about complex structure of QM vacuum then about ether.Vacuum turns to be far from being physically nothing.But,I stress again relativity does not describe QM phenomena.Properties of QM vacuum support to the great extent relativity,but link with spacetime concept in relativity and QM vacuum is still troublesome to reach.
_____
*Maxwell's ether constructed of ideal cog wheels and similar ideal fluid funny
things.

[billy_boy_999]

okay, so in quantum mechanics we understand that there is something more than nothing in a vacuum but we can't easily marry that with relativity...

this is making things much clearer to me...i refuse to accept that a vacuum can possibly be empty for light to pass through it...if light is truly a wave then it must be a wave "in" something...a ripple in spacetime or in the dynamic vacuum...no?...and for light's speed to be reactive, as in constant regardless of relative velocity, it must be reactive against something...

[wisp]

Billy boy 999

secondly, doesn't the fact that lights speed cannot be affected by the speed of a body that emits it suggest the existence of an ether?

Very much so, Maxwell's equations were developed using an elastic ether medium and they predicted that electromagnetic waves travel at speed c, which turns out to be the same as light.
Up until Einstein's SR, everyone was thinking in terms of light propagating through the ether. Now everyone thinks in terms of spacetime, which doesn't require an ether.
But there is no proof that space and time are joined together and no experiment has been done to prove the ether doesn't exist, so maybe your right.

wisp

"particles of nothingness"

[jdavel]

billy boy 999 said: "if light is truly a wave then it must be a wave "in" something"

Why? Do you feel the same about a static electric (or even magnetic) field. Does there have to be "something" around an electric charge for you to believe that there can be an electric field extending out from the charge?

Another thing. Suppose you had never heard of waves (any kind of wave), and then you saw Maxwell's equations for the electric and magnetic fields and how you can combine them into an equation which has solutions of the form Asin(kr-wt). Then you realize this means that if at a certain time and place the field has a given strength, that at some later time and at a point further out on the r axis it will have this same value. Now you know all there is to know about this field. Do you think it would occur to you at that point to suggest that this field that varies periodically in time and space "must be in something"? I don't think it would.

I think the reason that people insist on thinking that an EM wave needs a medium is just because other waves (although not all other waves) have them.

The EM wave is just a solution to some equations that tells what the force is on charges at points in space. Just because the same sort of solution shows up as a disturbance in media that have mass, should in no way lock us into to insisting that it always has to.

[yogi]

wisp - yes - maxwells first papers were developed along the lines of an elastic medium - vortex tubes and the like - but later on he abandoned much of what he thought was necessary for propagation - reducing it to the intrinsic properties of permeability and permittivity. To me, the thing that has to be abandoned about the notion of an ether is that it consists of entities like the molecules of a gas or a fluid that has a positive pressure - the properties of the spatial medium are "sui generis" ...we seem to be perpetually engaged in trying to relate it to something we have experience with - I can concur with the idea that an oscillating magnetic and electric field could be self sustaining without the presence of a medium - but space has measurable properties aside from the above electrical values - Dirac for example, argued that the vector potential must involve the rotation of something (consider the voltage induced in a loop of wire by a changing magnetic flux- the induced voltage is the same no matter how large the loop) - the entire magnetic field can be confined to a small iron core passing through the loop at its center, but the loop can be a mile in diameter - yet the induced voltage is always equal to the time rate of change of the flux passing through the loop - how does the confined flux communicate with the loop? The vector potential leads to a circulation - but there is no electrical field measurable outside the confining iron core - So if you believe that this is due to some form of ethereal spatial circulation as suggested by Dirac, you are in pretty good company -

[wisp]

Why? Do you feel the same about a static electric (or even magnetic) field. Does there have to be "something" around an electric charge for you to believe that there can be an electric field extending out from the charge?

Yes, a medium that allows force to transmit through it is better than having nothing (absolute emptiness). Consider two small pieces of matter separated by absolute empty space. Now, how can these pieces be pulled together by gravity or electric forces. Only the ether medium through which forces can act can explain this. Without the ether medium, forces cannot act.

If you accept that forces are some magical things that are attributed to bodies then we must assume that the speed of light is dependent upon the motion of the source. And we know that this is not true and so the ether must be the medium through which light travels.

[Chi Meson]

Yes, a medium that allows force to transmit through it is better than having nothing (absolute emptiness). Consider two small pieces of matter separated by absolute empty space. Now, how can these pieces be pulled together by gravity or electric forces. Only the ether medium through which forces can act can explain this. Without the ether medium, forces cannot act.

If you accept that forces are some magical things that are attributed to bodies then we must assume that the speed of light is dependent upon the motion of the source. And we know that this is not true and so the ether must be the medium through which light travels.

I don't agree. First of all, the notion of force-carrying particles is no less "magical" than the notion of ether. Furthermore, the assumption of the existance of these particles does not say that their speed will be dependant on the motion of the source; in fact, it makes much more sense to me that their speed should not be dependant on the motion of the source.

The introduction ofthe classical, incompressible super-fluid ether presents problems that are no less evasive than the SR & GR model. Supporters of the ether have come up with their own elaborate models that do appear to be quite valid, and ultimately I (personally) have to admit that there is a stalemate as to the final proof.

This is a good time to point out the sticky thread at the top of this forum: the section that describes Einstein's re-introduction of "Aether" would serve this thread very well. It's too bad Einstein and Maxwell never got to work with each other.

[TeV]

The introduction ofthe classical, incompressible super-fluid ether presents problems that are no less evasive than the SR & GR model. Supporters of the ether have come up with their own elaborate models that do appear to be quite valid, and ultimately I (personally) have to admit that there is a stalemate as to the final proof.
I agree,classical incompressible super-fluid concept impose more questions and paradoxes in physics than simple spacetime geometry concept.
Is there a single measurable observable phenomenon in physics that contradicts GR or quantum physics predictions ,that requires introduction of ether as some sort of must existing medium structure that is advantageos over usual spacetime concept?If there's not,why to complicate things than?
Btw,spacetime concept from the physical (and metaphysical) standpoint is even more mysterious than "ether" to me.From the mathematical standpoint it is simple ,and that's why for use.

[wisp]

Yogi

It is possible that permeability and permittivity are properties of the ether.
It is quite amazing that Maxwell developed his equations on an elastic ether model and the equations then reduce to terms that become independent of the ether.

You are right in that the first problem in encountered with traditional ether is that of positive pressure slowing matter down (ethereal drag). But matter doesn't push through the ether, it is part of the ether and its motion through it is in the form of waves (the ether is displaced perpendicular to matters motion, and so the opening forces are equal and opposite to the closing forces). And so matter can move through solid ether without being impeded.

[yogi]

Wisp - yes - I agree that there is no impediment to motion vis a vis the aether - actually, we are only 300 years behind the times in coming to this conclusion -
D Alambert's showed that there is no drag in an ideal fluid - irrespective of the shape - this was a shocking revelation at the time - but if the ether functions as a propagation medium, must be the ideal fluid, and that should obviate the problem commonly brandied about re ether drag.

With regard to Chi meson - there is a bias that strems from analogy with velocity in water that is always taken to heart when discussing the ether - i.e., that the ether must be nearly incompressible in order for light to propagate at c ----- this is not at all necesary - in fact it overlooks the low value of the average cosmic density i.e., the modulus can be highly compressible because the density is so low v = (B/rho)^1/2 where B is the modulus and rho is the density - using a density that corresponds to a critical universe (10^-26 kgm) and a modulus about equal to G, you get the velocity of light c.

[russ_watters]

I don't agree. Neither do I. Wisp, you (as I'm sure you know) are searching for a classical explanation for a non-classical phenomenon. Light simply does not and cannot work the way other waves do.

You like to argue that there is no proof that there is no ether and that SR doesn't completely rule one out. That's quite true. The part you ignore is that science requires positive proof, not negative proof: ether has not been observed and the equations work just fine without it, therefore it must be assumed to not exist.

The question I have for you is: When? When will you abbandon ether? When has enough effort been put into failed attempts to find it that you will conclude it doesn't exist? If the answer is 'never,' and I rather suspect it is, you may want to re-examine the mindset from which you approach science.

[billy_boy_999]

Chi Meson:
Furthermore, the assumption of the existance of these particles does not say that their speed will be dependant on the motion of the source; in fact, it makes much more sense to me that their speed should not be dependant on the motion of the source

why is this? why does it make more sense this way?

it seems that this topic elicits a little civil scientific rancor from some people, which is good to read, i like it, keep it coming guys... :wink:

and i'm hearing that maxwell's equations - while originally formulated on the basis of an ether - actually drop the necessity of one...a pretty intuitive thing to think is - hey, the equations are trying to tell us something! so that feels like an intuitive argument against 'ether'

it seems like one of the problems is a confusion about the word 'ether' because its a historically loaded word, but can we not toy with the idea of permittivity and permeance of vacuum as being qualities of a much different and dynamic vacuum that we can - for the sake of a visualization - call 'ether'?

TeV:
Is there a single measurable observable phenomenon in physics that contradicts GR or quantum physics predictions ,that requires introduction of ether as some sort of must existing medium structure that is advantageos over usual spacetime concept?If there's not,why to complicate things than?

one of the reasons i brought up this topic of 'ether' (which i know almost nothing about but definitely more than i did! thanks guys) was because there seem to be some fundamental things about EM radiation and why c is the value it is that at least i don't well understand, and it sounds like there are still some things that are universally not well understood also...

so is it then not useful to consider the existence of an 'ether' or a medium of a kind we haven't been able to articulate in science to help us imagine why light acts the way it does? i am now sorry i began using the word 'ether' but i don't think a theory should ever be abandoned if it it is still the object of useful debate...

[yogi]

I wouldn't count out the ether - it probably doesn't have a particle structure as other mediums - but it exerts a reactionary force when masses are accelerated - and it is itself conditioned by matter as Einstein told us so many times - it has a characteristic impedance that we match to antennas to radiate max power transfer, a capacitance, an inductance that combined, dictate the velocity of light - that in and of itself is significant in terms of its reality - it is probably in tension as would be the case if space is a false vacuum, and accordingly this explains why it can support transverse wave propagation. Nothing in SR reveals why time proceeds differently in different reference frames - ether theory provides a physical link - although none of the various versions are necessarily correct - yet they do encourage us to seek to understand the nature of the void, and to endeavor to find a physical explanation for relativistic effects. If it is in tension, then it exhibits stress - stress fields imply stored energy - probably most of the cosmic energy exists in aetheral stress - so the dark matter that is sought for critical density may be exist in the form of stress energy. I will bet on some form of ether - we now know that there are several reasons why MMx and other experiments failed to detect the earths motion relative thereto, and we now have the CBR that gives good reason to suspect that we are moving relative to a stationary medium - in fact we can even detect the yearly variation in the CBR to show that we are moving relative to something

[wisp]

Dirac for example, argued that the vector potential must involve the rotation of something (consider the voltage induced in a loop of wire by a changing magnetic flux- the induced voltage is the same no matter how large the loop) - the entire magnetic field can be confined to a small iron core passing through the loop at its center, but the loop can be a mile in diameter - yet the induced voltage is always equal to the time rate of change of the flux passing through the loop - how does the confined flux communicate with the loop? The vector potential leads to a circulation - but there is no electrical field measurable outside the confining iron core - So if you believe that this is due to some form of ethereal spatial circulation as suggested by Dirac, you are in pretty good company -

I agree this does suggest an ethereal spatial circulation. However, I believe the ether has mass and so it is not the ether that rotates, but rather the magnetic pattern rotates in a "stationary" ether. This is similar to a sine wave pattern moving down a fixed string. A crude analogy - think of an electric field as a bicycle spokes pattern. The spokes rotate about an axis creating a magnetic effect. In this case the rotating pattern doesn't cause ether rotation.

[TeV]

I agree this does suggest an ethereal spatial circulation. However, I believe the ether has mass and so it is not the ether that rotates, but rather the magnetic pattern rotates in a "stationary" ether. This is similar to a sine wave pattern moving down a fixed string. A crude analogy - think of an electric field as a bicycle spokes pattern. The spokes rotate about an axis creating a magnetic effect. In this case the rotating pattern doesn't cause ether rotation.
In theory of relativity magnetic and electric fields a sort to say "the same things".
IOW,what is E-field in first reference frame can appear to be B- field in another in relative motion to the first one and vice versa.Even though relativity, doesn't explain origin of Maxwell's EM (matter of fact it is the opposite case),classical EM gets nice interpretation through it.
QED rise electromagetics to yet another level,and not just that:P. Dirac predicted possibility of magnetic monopoles.(Yet to be detected).I just thought it is worth mentioning it.
I'm cuirious to know how pushers of any kind of "(a)ether" theory explain the absence(?) of retarded EM radiation of charge accelerated by gravity field?

[TeV]

To be more specific on the last sentence:consider "centripetal force" orbiting motion of charge in gravity field of say spherical mass object.Ie. charged particle in the geodesics trajectory of external G-field doesn't emit EM radiation.
How an aetherist explain this?

[Chi Meson]

Chi Meson:
why is this? why does it make more sense this way?


It makes sense to me, having had 20 years to contemplate SR and GR and electromagnetic induction. Although I don't have any new insights into the theories, and I certainly don't understand them fully, I have no problem with believing that the "fabric of space-time" does not need to be constructed of any sort of material.

But the constant references to the "warping" and "curving" of space-time, as an analogy, continually supports the notion of "fabric" and therefore of "matter." It is within this analogy that Einstein makes reference to the "aether."

Either way you look at it, we either have "nothingness" that creates the appearance of being made of a maleable medium, or we have "stuff" that has miraculous properties that must be explained yet can't be measured.

As I said before, there is a stalemate but I have to concur with Russ' point: we have a model that does NOT require an aether; this model works; we can't detect the aether; therefor we ought to assume that there is none.


it seems that this topic elicits a little civil scientific rancor from some people, which is good to read, i like it, keep it coming guys... :wink:


Lots of people don't like to find that they've been wrong for 20 years. But this is probably why ether persists.

[yogi]

Wisp - does your belief in ethereal mass embrace particles with mass - or some form of stress energy that is distributed.

If the magnetic field rotated wrt to the ether - why would we not be able to detect it by some sort of em device - aethereal rotation would not be measurable by any device we know of - ergo there does not appear to be any form of coupling that we can relate to in order to explicate the induced voltage in a distant loop

[David]

it seems that this topic elicits a little civil scientific rancor from some people, which is good to read, i like it, keep it coming guys... :wink: ..



Here, see this:

http://adsabs.harvard.edu/cgi-bin/nph-bib_query?2001EPJC...21..701S

See the headline at the top:

NASA ADS Physics/Geophysics Abstract Service

See:

http://adswww.harvard.edu/

Here is one of Dr. Su’s main papers on this subject

“Quantum Electromagnetics – A Local-Ether Wave Equation Unifying Quantum Mechanics, Electromagnetics, and Gravitation,”

http://qem.ee.nthu.edu.tw/outline.pdf

The European Physical Journal is a mainstream journal, and Dr. Su’s papers are the latest contribution to the field of quantum mechanics about this very subject.

Dr. Su’s papers have been published in many languages in many mainstream physics journals around the world

[ahrkron]

I took a quick look at it. Two things I can mention: his main equations are not diffeo invariant, which make them incompatible with GR (and most probably with experimental results that agree with it... i.e., all to date), and every one of the references in the last link you provide are to CC Su! I wouldn't use it.

[David]

I took a quick look at it. Two things I can mention: his main equations are not diffeo invariant, which make them incompatible with GR (and most probably with experimental results that agree with it... i.e., all to date), and every one of the references in the last link you provide are to CC Su! I wouldn't use it.


You can go to Google and type in LOCAL ETHER SU, and find many of his other papers and his citations of experimental results that conform to and support his new theory. This is a reputable guy, well published, mainstream, published in major journals around the world. This is very new information, so it will take a while to be widely accepted. Also keep in mind, that many physics books over the years have said that there is a basic incompatibility between GR and quantum mechanics theories, so don’t be surprised if you read quantum mechanics theories that don’t support some of the principles of GR. Science changes. New theories are developed. Many old ones don’t remain the same forever. Anyway, NASA and Harvard people thought enough of his ideas to carry his papers on their websites. If you have some sort of mathematical or experimental proof that he is wrong, you can submit your own papers to the NASA and Harvard websites, and to the same journals that have published his papers.

[russ_watters]

David is using us as a new audience for his bunk ideas. Dr. Su's paper is discussed HERE (http://www.badastronomy.com/phpBB/viewtopic.php?t=9731&postdays=0&postorder=asc&start=1925). Dr. Su himself admitted that his hypothesis does not match observations. "It is seen that the two Bragg reflections are asymmetric, as predicted by the local-ether model. However, the agreement is not good quantitatively. [emphasis added]David keeps bringing it out for new audiences, hoping they won't figure these things out.

[David]

Dr. Su's paper is



If you don’t want to believe any particular quantum mechanics theory, that is fine with me. If you disagree with quantum mechanics papers published on NASA and Harvard websites, that’s fine too. That’s your business. This thread is about “ether”, and that’s what Dr. Su writes about. The entire group of Dr. Su papers explain what he said in the link I posted above:

“In spite of such a restriction on reference frame, the consequences of this new classical
theory account for a wide variety of experiments with the propagation or
interference of electromagnetic wave, and are in accord with another variety of experiments
commonly ascribed to the special relativity, the general relativity, the Lorentz
mass-variation law, or to the de Broglie matter wave. These experiments include
the Sagnac effect in GPS, the intercontinental microwave link, and in the rotating loop
interferometry; the round-trip Sagnac effect in the interplanetary radar; the
apparently null effect in the Michelson-Morley experiment; the constancy of speed of
light radiated from a moving source; the spatial isotropy with phase stability in the
Kennedy-Thorndike experiment and the one-way fiber-link experiment; the Doppler
shift in Roemer’s observations and CMBR; the effects of a moving medium in Fizeau’s
experiment and the Sagnac loop interferometry; the light deflection by the Sun; the
gravitational effect on the interplanetary radar echo time; the gravitational redshift
in the Pound-Rebka experiment; the speed- and gravitation-dependent atomic clock
rate in GPS, the Hafele-Keating experiment, and in spacecraft microwave links; the
spatial isotropy with frequency stability in the Hughes-Drever experiment; the resonant
absorption in the Ives-Stilwell experiment, in the output frequency from ammonia
masers, and in the Mossbauer rotor experiment; the matter wavelength in the
Davisson-Germer experiment and the double-slit diffraction; the matter-wave Sagnac
effect; and the effects of earth’s rotation and gravity in the neutron interferometry.
Meanwhile, this theory leads to some predictions, particularly the effects of earth’s
motions, which then provide different approaches to test the validity of the local-ether
wave equation.”

If you choose not to believe this and to ignore new quantum mechanics theories published in major science websites, then that is your business.

[yogi]

The local ether model appears every bit as good as GR and SR in many tests - Admittedly I didn't consider it worth much when I first came across it a year or so ago (probably because I didn't think of it) -- but it seemed like a last gasp ad hoc effort of the ether gang to preserve the notion of a medium - now i am not so sure that it doesn't have merit - from the perspective of GR a good arguement can be made that the conditioning of space by matter
"a la" Einstein would necessarily lead to aetheral geocentricity as to those properties of the medium upon which the propagation of light depends.

The idea should be viewed fairly - without invoking the tenants of relativity as God given truth to be used to disprove every other idea that is not compatible therewith. If Su's theory fails on its merits - so be it. If its not consonant with some doctrine of SR or GR, then maybe the problem lies with the home team and not the challanger.

[russ_watters]

The idea should be viewed fairly - without invoking the tenants of relativity as God given truth to be used to disprove every other idea that is not compatible therewith. If Su's theory fails on its merits - so be it. If its not consonant with some doctrine of SR or GR, then maybe the problem lies with the home team and not the challanger. Dr. Su's theory fails based on the data - that has nothing at all to do with how it compares to SR/GR.

David, no one is saying that a local ether theory can't account for some or even a lot of the data. Just that it also can't account for a lot of the data.

[yogi]

Russ - it apparently stumbles on the issue of aberration as to the earth's orbit - what else?

[wisp]

Russ - it apparently stumbles on the issue of aberration as to the earth's orbit - what else?

This is a serious flaw in "local" ether theories, as it's a basic test that must be addressed.

A non-local ether would pass the aberration test.

wisp

"particles of nothingness"

[DrChinese]

What known problem in SR does adding an ether solve? To simply say it has a lot of promise is meaningless. Any challenger theory is an "ad hoc" theory unless it accounts for something BETTER than SR.

Besides, you can talk about SR "implying" no ether all day long... but it doesn't really say that at all. At SR really says is that its formulas work independently of an ether, if there is one. Ditto for GR.

[yogi]

Wisp - agreed - but I wonder if the operative is different from the notion of ether drag - if the putative medium is collectively stationary with respect to the moving earth, then we should not detect annual aberration (which we do) - but if the local ether admits of a different construct such that the conditioning progresses in the direction of motion - then it may not be necessary to consider the local ether as stationary with respect to the earth as to light sources originating beyond the local influence - but then how does the theory explain diurnal aberration? Something inconsistent at my level of comprehension of the theory - but I have similar concerns about SR - the triplet paradox, Sagnac and the lack of a physical foundation.

[russ_watters]

Russ - it apparently stumbles on the issue of aberration as to the earth's orbit - what else? Quite frankly, I haven't read much of his - thats the only example I have.

A proponent would argue (correctly) that there are a lot of experiments that it can explain. I'm not interested: in fact, thats absolutely trivial. The whole reason to make a new theory is to explain more known data than other theories, not less. Otherwise, it would be equally valid to go all the way back to Newton's laws - they explain a lot of observations too.

Here is what ether theories give you: more assumptions and less accurate predictions. They are a giant leap in the wrong direction.

I asked a question on the bottom of the first page that wasn't answered. It was addressed to wisp, but I'd be interested in what other ether proponents have to say. How/why ether proponents cling to the idea positively flabbergasts me.

[billy_boy_999]

i can't claim to be a proponent of 'ether theory', but i can't help feeling there some of these disagreements are wrapped in semantics...

can we not do away with the word 'ether' - or at least redefine it as the properties of permeability and permittivity of vacuum? or if we can say that 'ether' is simply the unknown qualities of vacuum or the unknown physical qualitities of space-time, surely proponents are not 'clinging to' anything...it is simply an avenue for approaching some of the unsolved riddles of EM radiation, dark energy, dark matter, CBR, etc.

in this way, i don't see 'ether theory' as a giant leap in the wrong direction at all, but a useful tool and consideration for modern theorists...it seems logical to me that until these mysteries are solved or until we can fundamentally disprove the ether it is still worth clinging to it in a sense that it would seem foolish to discard it or depend on it...

[yogi]

Why consider an ether theory? - for one thing I think its natural to want to relate time dilation and the other consequences of SR to something physical. An ether theory is essential for GR - there has to be something to distort. My own feeling is that some type of ether is necessary to explain inertia - how can an inertial force arise instantaneously to oppose acceleration unless there is some local property of space that is involved. As Russ points out - there is no reason to dabble in alternatives that do not do a better job - so to reiterate a couple of points here that everyone is already familiar with --- an ether theory immediately says that time dilation is real not apparent (a conclusion that is difficult to pin down as to what Einstien's himself actually believed after he discovered the principles of GR). This at once resolves the triplet paradox where relativity has not be satisfactory - an ether theory also appears better able to explain CBR anisotrophy - and for my money Sagnac (although relativist can and will take issue with that statement). Now in making these statements, I do not mean to imply a particulate ether - I think we will be able to determine the spatial properties - and collectively we will call the sum total of these properties an ether as suggested by Billy Boy 999. Thats my 2 cents which is about what ist worth

[russ_watters]

can we not do away with the word 'ether' - or at least redefine it as the properties of permeability and permittivity of vacuum? Its already been done: Einstein himself used that definition. But this thread is about a classical ether. No, I don't think there is a semantic issue here (though there is an Einstein quote often misrepresented by classical ether proponents to make it sound like he was a classical ether proponent).

[Hurkyl]

how can an inertial force arise instantaneously to oppose acceleration unless there is some local property of space that is involved

Why do you think there's an inertial force that opposes acceleration?


This at once resolves the triplet paradox where relativity has not be satisfactory

Would I be hijacking if I asked yogi to explain why he thinks relativity is not satisfactory to explain the triplet pseudoparadox?

[yogi]

Hi Hurkyl - without getting to far off the main topic - the inertial force - I was referreing to F = ma ... why does acceleration of a mass with respect to space produce a reactionary force?

Triplet - in the triplet version - there is no acceleration - the outbound sibbling simply transfers his clock reading to an inbound third triplet - there is no acceleration felt at this transfer - so the traditional twin explanation often relied upon by relativists, including Einstein in his early papers, to wit: "that the turn-around twin feels the acceleration - therefore the experiment is not symmetrical" - is no longer applicable.

[yogi]

Back to Russ re aberration - I wonder if the author of the article has not mislead himself by stating: "....there forms a local ether which in turn is stationary with respect to gravitational potential of the respective body. Thereupon, each local ether together with the gravitational potential moves with the associated celestial body..."
The question I have is why is it asserted that the putative ether is stationary with respect to the moving earth. This makes the local ether identical with the notion of ether drag - ergo there can be no aberration. But if instead, the earth conditions the medium as it moves through it, aberration will be observed wrt to extraterrestrial light sources. In words, it is possible for the local ether to be isotropic at the instant of measurement, but not attached to the earth or stationary wrt. For example, if the propagation property of the void depends upon the degree of stress, and it is posited that matter influences the local stress field, then a spherical mass would produce an isotropic stress field. This stress field will move with the mass, but the medium itself will not. An MMx experiment carried out using a local light source will yield a null result, but the aberration effect will also be observed.

[russ_watters]

Triplet - in the triplet version - there is no acceleration - the outbound sibbling simply transfers his clock reading to an inbound third triplet - there is no acceleration felt at this transfer - so the traditional twin explanation often relied upon by relativists, including Einstein in his early papers, to wit: "that the turn-around twin feels the acceleration - therefore the experiment is not symmetrical" - is no longer applicable. If the clocks are never in the same frame, they are never really synced either. So this example doesn't really have anything to say about SR: you've discarded the thought experiment's reason for existing. Hi Hurkyl - without getting to far off the main topic - the inertial force - I was referreing to F = ma ... why does acceleration of a mass with respect to space produce a reactionary force? I wouldn't characterize inertia as a reactionary force. The phrase "with respect to space" is similarly meaningless: acceleration occurs with respect to a fixed reference point (generally the starting point of the acceleration). Are you asking why inertia exists? You've lost me too.

RE: Local ether. How local? We've conducted tests of Relativity with satellites and deep-space probes.

I ask again: How far? How much? How many? At what point do you guys discard this line of study?

[yogi]

Russ - all the travelers can be in the same frame. The stay at home guy J sync's with the outbound twin Y as he cruises past J headed east after starting from a point west of J - Y continues at a constant velocity until he meets an inbound traveler X at the point where he would have turned around - but instead of decelerating he simply flashes his clock reading to X who returns to J at a constant inbound velocity. The path integral for the total time recorded by X and Y will be less than that recorded by J. There is no acceleration and all measurements of velocity are made wrt the earth frame. There are many articles on this particular aspect of why the conventional acceleration interpretation doesn't work in SR. The problem is at once solved however, if time dilation is real not apparent.

Russ -- Any time a body undergoes a change in velocity, there is an inertial reactionary force - it is not measured with respect to a particlular point - it is an inherent property of the universe - you will get the same force according to Einstein if you held the mass still and accelerated the universe

[Hurkyl]

The path integral for the total time recorded by X and Y will be less than that recorded by J. There is no acceleration and all measurements of velocity are made wrt the earth frame. There are many articles on this particular aspect of why the conventional acceleration interpretation doesn't work in SR. The problem is at once solved however, if time dilation is real not apparent.

If you're following the "information" around, you'll notice that it changes reference frames when it goes from the outbound triplet to the inbound triplet. Thus you must apply a Lorentz transform, which has the same net effect as the acceleration. *shrug*

[russ_watters]

Russ - all the travelers can be in the same frame.

...all measurements of velocity are made wrt the earth frame. These two statements are mutually exclusive. By definition, 3 objects moving relative to each other are not in the same frame.

[yogi]

Each entity carries his own clock in his own inertial frame - but in the definition of the problem, the velocities of X and Y are measured with respect to the earth frame. Time measured by the clock carried by the inbound entity X will run at the same rate as time measured by the clock carried by the outbound entity Y - if both of X and Y have a speed v wrt the earth, then the X and Y clocks will run at the same rate just as though they were in the same inertial frame. If SR predicts a difference in time for a single entity turning around - and using the acceleration rationale to explain the change of coordinates - the triplet problem should also lead to the same difference in time between the totaltality of the times logged by X and Y as compatred to J

Tell me Russ- in the triplet problem - do you think that the clock reading on X's clock when he passes by J will be equal to or different from the time logged by J's clock?

[yogi]

Hurkyl - that is one of the ideas conjured up to save SR - what is your authority? - there is no experimental evidence - other solutions take the position that initially Y and J are not symmetrical because at some point in the past one or the other must have undergone a change in velocity in order for the two to be in relative motion - and that is the reason why these clocks run at different rates from the start - even though they both get set to zero as Y passes J .... - you can apply your solution to the beginning as between J and Y as well as between Y and X .... I have toyed with this same line of thought - but I don't believe it leads to a very satisfying rationale

[Janus]

Triplet - in the triplet version - there is no acceleration - the outbound sibbling simply transfers his clock reading to an inbound third triplet - there is no acceleration felt at this transfer - so the traditional twin explanation often relied upon by relativists, including Einstein in his early papers, to wit: "that the turn-around twin feels the acceleration - therefore the experiment is not symmetrical" - is no longer applicable.

The acceleration in the Twin paradox is only needed to reconcile total elasped Earth time as measured by the stay at home twin with that as measured by the traveling twin.

In the triplet version, again all we need to do is reconcile what each triplet measures as the outcome.

Thusly:

Assume Triplet 1 sits at home.
Triplet 2 is outward bound at .866c relative to triplet 1
Triplet 3 is inward bound at .866c. relative to triplet 1
Triplets 2 and 3 pass each other 10ly from triplet 1 as measured by triplet 1

Thus from the view of triplet 1:

Triplet 2 takes 11.55 years to travel out to 10ly
Triplet 2's clock will only show 5.775 yrs at this point.

time from triplet 2 is transfered to triplet 3.

Triplet 3 takes 11.55 years to travel inward from 10ly, for a total elasped time of 23.1 years by triplet 1's clock.
Triplet 3's clock gains 5.775 yrs at this during this time, for a total elasped time of 11.5 years.


From triplet 2's view:

Due to length contraction, he travels out to 5ly until meeting triplet 3, at which time his clock reads 5ly/.866c = 5.775 yrs.
Triplet 1's clock would read 2.8875 yrs at this point.

time from triplet 2 is transfered to triplet 3

triplet 3 is moving at

\frac{.866c+.866c}{1+\frac{.866c^{2}}{c^{2}}}

or .9897c relative to triplet 2 as measured by triplets 2 & 3.

With triplet 1 receding at .866c and triplet 3 chasing at .9897c, it will take

\frac{5ly}{.9897c-.866c}= 40.41 yrs

by triplet 2's clock for triplet 3 to reach triplet 1

In which time triplet 1's clock will advance by 20.205 yrs. Add this to the 2.8875 yrs elasped previously and you get 23.1 years total elapsed time for triplet 1; The same time as measured by triplet one.

Triplet 3's clock will advance by

40.41yrs \sqrt{1-\frac{.989739c^{}2}{c^{2}}} = 5.775 yrs

The same time that triplet 1 sees this clock advance by. Add this to the 5.775 yrs transfered from clock 2, and you get a total elasped time of 11.55 yrs; again the same time as measured by triplet 1.

So far, triplets 1 & 2 both agree as to what the clocks read.

From the view of triplet 3:

He passes triplet 2 at 5 ly distant from triplet one and takes on the clock reading of 5.775 years. He takes 5.775 years to cover this distance a .866c, thus his clock reads 11.55 yrs upon reaching triplet 1; Again in agreement with triplets 1 & 2.

During this time he will see triplet 1's clock advance by 2.8875 yrs.

Now we must determine what time it is on triplet 1's clock according to triplet 3 at the time triplet 2 and triplet 3 pass each other.

We must assume that either triplet 1 sends out a signal to triplet 3 when triplet 2 leaves or triplet 3 is watching with a very powerful telescope and notes the time.

Since this info is moving away from triplet 1 at c as measured by triplet 1 and triplet 3 is moving in at .866c, triplet 3 will intercept this info when it is 10.72 lys from triplet 1, as measured from triplet.

From triplet 3's perpective this interception happens at 5.36 ly (again, this is due to length contraction.)

Having received this information, triplet 3 can now extrapolate back to when this info was sent. Since the info traveled at c wrt triplet 1, and triplet one is approaching at .866c, the time since emission(and triplet 1's clock reading 0) would be

\frac{5.36ly}{1c-.866c}= 39.99 yrs.

it will take an additional 0.4157 years by triplet 3's clock to intercept triplet 2
giving a total elapsed time at this point of 40.41 years since the initial launch of triplet 2. With time dilation factored in, triplet 1's clock would read 20.205 at the time of the passing of triplets 2 and 3, according to triplet 3. Adding this to the 2.8875 yrs that passes on triplet 1's clock while triplet 3 travels the remaining 5 ly, and you get a total elapsed time of 23.1 yrs on triplet 1's clock according to triplet 3. This again agrees what what triplets 1 & 2 measured.

Also, since triplet 2 is moving at .9897c relative to triplet 3 as measured by 3, applying time dilation for this velocity will show that triplet three will see triplet 2's clock advance by 5.775 yrs form time of leaving triplet 1 to intercept.

Thus all three are in agreement, and there is no paradox.

[yogi]

Hi Janus - thanks for your scholarly treatment of the triplet problem. While I have not gone through it all in the detail it deserves, I wanted to make a comment initially regarding the subject. I agree there is in fact no paradox if time dilation is actual - we have discussed this in the past - and it seems that the differences turn upon the interpretation to be given time dilation. Specifically, I concur in your treatment through the first 13 lines. You state that the total time accumulated by triplet 2 and 3 to be 11.5 years. You also compute the total lapsed time on triplet 1's clock as 23.1 years. You state on line 7 (the transfer point) that triplet 2's clock will only show 5.775 years. I read this as saying ---this is the amount triplet 2 has aged during his outbound flight - this is what he reads on the clock which escorts him to the handoff point. If that is what you are saying, then the time that is missing from 2's clock must be real, and unrecoverable, i.e., the two frames are asymmetrical ab initio. We need not consider how triplet 2 views triplet 1 or 3 - since the difference between the clock readings after turn around or handoff is assured.

I would also concur with the fact that triplet 2 would believe he has traveled a shorter distance because he reads his own clock and the 0.866c velocity to compute how far he has traveled - but this is an apparent contraction since the proper length is 10 light years in the earth reference system. However, I do not see how this bears on the issue of temporal reality as implied in the triplet scenerio.

[Janus]

I would also concur with the fact that triplet 2 would believe he has traveled a shorter distance because he reads his own clock and the 0.866c velocity to compute how far he has traveled - but this is an apparent contraction since the proper length is 10 light years in the earth reference system. However, I do not see how this bears on the issue of temporal reality as implied in the triplet scenerio.

The fact that triplet 2 measures the shorter distance is not just due to calculation, it is real for him. Assume that there is a long cord stretched out along the travel path. It is marked at one meter intervals as measured by triplet 1. Triplet 2 carries a meter stick which travels along with him and is held adjacent and parallel to this cord.

As he moves along the cord, he will measure that there will be two cord intervals over the length of his meter stick, thus the cord intervals will be 1/2 meter apart, by direct measurement. By counting the marks on the cord as he passes them he can measure the distance he has traveled and it will be 5 ly.

You can also assume that triplet 2 is hauling a simular line behind him, marked off at 1 meter intervals according to his meter stick. If he looks back along the line at the instant he meets triplet 3, he will see find that it will mark off a distance of 5 ly between himself and triplet 1.

Both of these direct measurements concur that the distance between triplet 1 and 2 is 5ly by triplet 2's reckoning and that it is the real distance for him.

[russ_watters]

The fact that triplet two measures the shorter distance is not just due to calculation, it is real for him. Again, the usual problem people have with Einstein's Relativity is they are unwilling to make the jump from what the calculations say to the physically real: yes, yogi, I know its difficult to accept, but Einstein's Relativity is a mathematical model of a physically real phenomenon.

[yogi]

Janus, Russ - I have always found Eddington's analogy re length contraction amusing - here it is:

"You receive a balance sheet from a public company ... it is certified by a chartered accountant. But is it really true? Many questions arise; the real values of items are often very different from those that figure in the balance sheet...There is a blessed phrase "hidden reserves" and generally speaking the more respectable the company the more widely does its balance sheet deviate from reality. This is called sound finance ... the main function of the balance sheet is to balance and everything else has to be subordinated to that end. The writing down of lengths for balance sheet purposes is the FitzGerald Contraction. The shortening of the moving rod is true, but it is not really true. It is not a statement about reality (the absolute) but it is a true statement about appearances."

[yogi]

Anyway russ - janus - my primary interest in this subject is the reality of time disparity - I am always propelled to the conclusion that the rate at which clocks run is due to one of two physical causes - specifically there is ether a preferred rest frame and clocks are affected when they are set in motion relative thereto - OR if we locate an isotropic rest frame (not because of Einsteinian postulation - but because it will always be possible to find one somewhere) then if two objects are initially at rest in this isotroptic light frame, any change in the velocity of one of the objects relative thereto creates an asymmetry in the clock rates - and thereafter until the relative velocity is reduced at some later time, the clock which has been put in motion will always actually run at a slower rate than the one that stays-put

To me, this has to follow directly from the analysis of high speed particles - take the example of a pion which has a lifetime of 1.77 x 10^8 sec as measured by a clock attached to the pion (proper time as measured at one place attached to the pion) Now if we measure in the earth frame a distance of 10 light years to a star alpha, and stipulate that the earth alpha frame is an isoptropic light frame, then we whip the pion up to nearly the speed of light and aim it toward alpha, it will, in this scenerio reach alpha in 10+ light years. If the pion decays just as it arrives at alpha, the total time measured by the on board pion clock is 1.77 x 10^-8 sec since it is not affected by motion wrt the earth-alpha frame. The time passed in the earth frame is 10 years - how can it be argued that time dilation is not real? There is no turn around - no acceleration - no information is communicated between the earth lab and the pion - the two clocks are running at different rates from start to finish. If the interval is to constant as per SR, we have an asymmetry at the outset - not at the turn around acceleration - that is we have created a situation where we have specified proper time in one frame and proper distance in the other.

I would like your comments

[yogi]

Let me add a little more - since we have an asymmetry from the beginning - even though the two clocks can be synchronized after the pion acquires its velocity - I maintain it is improper to claim each sees the other clock running slow - that is a consequence of some short cut thinking -- it is what results when the home twin and outbound twin send transmissions to each other on the outbound journey - (it is really a Doppler affect misapplied to time dilation).. and things get reversed on the inbound journey. If there are a series of clocks established at various space stations along the way between earth and alpha - the traveling pion can observe that the clocks in the earth-alpha frame are running faster (much faster) than his own as he zips along (by reading the position of the hands on the faces of each successive clock)

[russ_watters]

yogi, have I mentioned how clocks work in GPS satellites...?

[yogi]

Russ - I have read a number papers on relativity and GPS. Here again there is a difference of opinion... primarily in connection with the explanations proffered to correct for the one way Sagnac effect (receiver motion relative in the earth centered reference frame due to the earths rotation). I would be happy to receive your thoughts with regard thereto.

[Nereid]

At the risk of diverting this interesting discussion, I am wondering if any 'ether proponent' has a specific prediction which is different from SR/GR? It doesn't have to be measurable with today's equipment and technology (though that would be very nice!), but should be unambiguously different.

IIRC, wisp has just such a concrete prediction, involving the 'one-way speed of light'; anyone else?

[russ_watters]

Russ - I have read a number papers on relativity and GPS. Here again there is a difference of opinion... primarily in connection with the explanations proffered to correct for the one way Sagnac effect (receiver motion relative in the earth centered reference frame due to the earths rotation). I would be happy to receive your thoughts with regard thereto. The operation of GPS has nothing to do with the Sagnac effect (which is, in any case, well accounted for by SR).

And who is this difference of opinion between? Any of the engineers who designed it and operate it argue over how to make it work?

[Nacho]

I read an article one time, and it might have bearing or enlightenment here on this topic. It was a Nobel Prize acceptance speech, I believe from one of the people that formulated weak interactions.

It was a very enlightening article. He (the author) talked about absolute quantities, like the speed of light, not as non-variating constants of nature, but as "non-observables" of symmetry breaking .. that is, we couldn't/didn't observe interactions that lead to that constant being broken in nature because of symmetry.

If anybody is interested, I could fish out the article, and cite a publication. It is a few pages long .. I couldn't post the whole article here. I could post it on a personal web site, but I'd have a hard time reproducing the formulas and special expressions/characters in it.

[yogi]

Russ - the difference of opinion lies in whether the corrections are best explained using SR or an ether theory - and yes, some of the persons who have acted as GPS consultants have advocated that the Lorentz ether theory better explains why you must use the earth centered reference system in GPS. But all that is really a side issue - there is a question pending for you and Janus - namely how do you explain the pion clock and the clock in the earth-alpha frame as posting different times when the pion arrives at alpha?? IS TIME DILATION REAL OR APPARENT?

[yogi]

Nereid - Although some experiments have been proposed to unambiguously determine which theory best describes reality - the issue may be more complex than a simple one or the other answer. If you read only a few of the many hundreds of articles that deal with the controversy, it is obvious that some of advocates on each side are very good at making their theory fit the facts. Moreover, there are some differences between relativists as to some issues (including the questions I have posed in my posts) and there are many differences among the Einstein Bashers.

[Nereid]

I read an article one time, and it might have bearing or enlightenment here on this topic. It was a Nobel Prize acceptance speech, I believe from one of the people that formulated weak interactions.

It was a very enlightening article. He (the author) talked about absolute quantities, like the speed of light, not as non-variating constants of nature, but as "non-observables" of symmetry breaking .. that is, we couldn't/didn't observe interactions that lead to that constant being broken in nature because of symmetry.

If anybody is interested, I could fish out the article, and cite a publication. It is a few pages long .. I couldn't post the whole article here. I could post it on a personal web site, but I'd have a hard time reproducing the formulas and special expressions/characters in it.If it's as you say, then it should be available somewhere on the web; if you wouldn't mind taking the trouble to find it (or the author, title of the paper, date, ... something that PF members and guests who are dab hands at google can work on) then posting just a link would be helpful.

[Nereid]

Nereid - Although some experiments have been proposed to unambiguously determine which theory best describes reality - the issue may be more complex than a simple one or the other answer. If you read only a few of the many hundreds of articles that deal with the controversy, it is obvious that some of advocates on each side are very good at making their theory fit the facts. Moreover, there are some differences between relativists as to some issues (including the questions I have posed in my posts) and there are many differences among the Einstein Bashers.Thanks yogi; this is partly why I used the words 'specific' and 'unambiguously' :smile:

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?

[russ_watters]

...there is a question pending for you and Janus - namely how do you explain the pion clock and the clock in the earth-alpha frame as posting different times when the pion arrives at alpha?? IS TIME DILATION REAL OR APPARENT? Both of us already answered that question. How many times do you want it answered and in how many different ways?

Me:Again, the usual problem people have with Einstein's Relativity is they are unwilling to make the jump from what the calculations say to the physically real: yes, yogi, I know its difficult to accept, but Einstein's Relativity is a mathematical model of a physically real phenomenon. Janus: The fact that triplet two measures the shorter distance is not just due to calculation, it is real for him. I don't think we can state it any clearer than that.

[russ_watters]

yes, some of the persons who have acted as GPS consultants have advocated that the Lorentz ether theory better explains why you must use the earth centered reference system in GPS. So are you acknowledging now that SR works? It is mathematically equivalent to Lorentz ether....

You, like many anti-Relativity guys, seem to flip-flop between saying it works and it doesn't work. In fact, it's the various ether theories that only work where they are equivalent to Relativity.

Have another look at the title of this thread. Its a good question from someone who was admittedly ignorant: "Doesn't light's constant speed dictate [require] an aether?" Answer: unequivocably no. It doesn't rule one out eiter, but there is currently no evidence that can only be explained via an ether.

[billy_boy_999]

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

yes, russ, thank you for re-stating my question...the reason i started this thread was that i was struck with the notion that there must be something limiting light's speed...the thought that photons are dropped onto one of those moving luggage conveyers comes to mind...i thought the ether might explain why there is a speed limit...

so, to summarize and to try and grasp all of this stuff (alot of which is way over my head btw) the fact that light has a constant speed is not a result of an 'ethereal speed limit' a kind of 'ethereal density' that limits light propagation, but the value of 'c' is still very much tied to the properties of permeability and permittivity in vacuum...is that basically correct?

if so, then two more quick questions:

1. do maxwell's equations agree with/rely on these vacuum properties? or are they simply superfluous?

2. do modern ethereists(?) use these properties of vacuum to describe the new 'ether' (vacuum-ether?)?

...basically, i was just wondering - why exactly is c - c? 300,000km/s?

[Tom Mattson]

1. do maxwell's equations agree with/rely on these vacuum properties? or are they simply superfluous?


The permeability and permittivity constants are built into Maxwell's equations, as they are necessary for the numerical predictions to be correct. When one uses Faraday's and the Maxwell-Ampere law to derive the EM wave equation, those two constants combine in a particular way to form the constant c, the speed of light.


2. do modern ethereists(?) use these properties of vacuum to describe the new 'ether' (vacuum-ether?)?


Due to the lack of extant modern ether literature, I don't know. I think that kind of research is mostly found on, well, internet discussion boards.


...basically, i was just wondering - why exactly is c - c? 300,000km/s?

Because c=1/(e0m0)1/2, and e0=8.99E9 Nm2/C2 and m0=4pE-7 Tm/A.

Now if we could just figure out why those two constants have the value they do...

[yogi]

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.

Nereid - the most compelling aspect of the alternative theories is that they seek a physical explanation of "why" SR has proved to be a successful calculating tool - and if time dilation is real, then there should be a tie to physics - what is there about different reference frames that can account for time slippage? That is why persons like myself are intrigued with the subject - there is a mystery - and in spite of the criticism heaped upon us for not blindly endorsing SR, the doctrine creates questions. I never cease to be amazed at the cock sureness of the advocates on both sides. Near the end of his life Einstein expressed doubts about his own great legacy, so why should we not be allowed the same doubts.

As to the question originally posed by originator of this subject (billy boy) as to whether the constant velocity of c implies and ether, let me offer one other tid bit. Perhaps the velocity of light is determined by the velocity of expansion, rather than vice versa. Expansion creates spatial stress (Einstien referred to a stress-energy tensor) and Alan Guth has suggested that inflation may be an ongoing proposition - the permeability and permittivity of the void may be determined by this ongoing tension a la Hubble expansion. If so, then the velocity of light may be uniquely dependent upon the properties of the void. Since Russ has can pontificate that the vacuum doesn't determine the velocity of light - I will go on record otherwise.

[Nereid]

*SNIP

Nereid - the most compelling aspect of the alternative theories is that they seek a physical explanation of "why" SR has proved to be a successful calculating tool - and if time dilation is real, then there should be a tie to physics - what is there about different reference frames that can account for time slippage? That is why persons like myself are intrigued with the subject - there is a mystery - and in spite of the criticism heaped upon us for not blindly endorsing SR, the doctrine creates questions. I never cease to be amazed at the cock sureness of the advocates on both sides. Near the end of his life Einstein expressed doubts about his own great legacy, so why should we not be allowed the same doubts.It seems that many folk are interested in SR from this "what's the physical reality" perspective. Seeing as how SR is 'just' a special case within GR, are you equally driven to examine alternatives to GR? Which such alternatives, that you are aware of, have as good a track record as GR of prediction and matching experiments and observations? How about QM/QFT? Aren't you even more interested to find alternatives which are less weird?

BTW, do you have a list of observational/experimental failures of SR or GR? To be frank, one of my frustrations is that none of the 'anti-s' has produced any.

Then there's utility - if GR and/or SR helps make the GPS work, or is necessary to calculate the band structures in semi-conductors (via QED), or explains the observed orbital decay rate in binary pulsars, ... why struggle with a set of much weaker alternatives?

[yogi]

As a mater of fact, there are very good reasons for considering alternatives to both GR and QED. GR is an incomplete theory because it does not predict the value of G - and it does not tell us why mass warps space. QED is but an alternative technique for resolving the perturbation expansion - Feynman searched diligently for a physical reality - ultimately proposing virtual photons. The fact that QED works great for the second order effect (gyromagnetic ratio) doesn't mean virtual photons really exist, QED does not explain at all why the electron has the charge it does - you have to put the numbers in by hand.

Why study alternatives? - to put the question is to answer it -- alternatives may lead to a better understanding of space - The inflow theory for example makes all the same predictions as GR To me, the fact that one has to put in the value of the constants by hand in all standard theories should provoke every thinking person to think further - i don't happen to believe that G, c, e, h or any of the other so called constants are God given values - there is a physical reason why they have the values they have - and existing theory(s) in general do not deal with these questions - yes GR, SR and QED are good tools - but some of us are not content with formulas just because they give right answers - whether the alternatives are "weaker" remains to be seen - you have been taught one way - if technically educated individuals cannot see beauty in the mysterious - the unknown, the yet to be discovered - that is unfortunate.

"It is a wonder that modern methods of instruction have not totally strangled the holy grail of curiosity" ... Albert Einstein

As for the failures of the standard theories - they cannot be called failures per se - it can always be asserted that standard theory gives an adequate account as did the geocentric theory (for a while). But by who's definition is a failure identified - things get subjective quickly - some results that can only be explained with difficulty in one theory dissolve within the framework of another.



"

[Nereid]

Thanks for the clarifications yogi.

What is 'the inflow theory'?

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

[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 earths 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 :wink: 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 earths 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]

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' :smile:

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 earths 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"...? :confused:

"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! :wink:

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." :smile:

[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! :wink:

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." :smile:au contraire mon ami! :eek: 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! :wink:

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". :biggrin:

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 :cool: )

[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 earths 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 = Prof Stefano 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 :wink: ), you'd be quite heartened about how far we are from falling into the kind of bear trap you describe. :smile:

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 knowledgable 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 any one 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 existance 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 existance 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 earths 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 particals 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, does'nt 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.

[Janus]

For now, I'm going to lock this thread. pending further review.

As is stated in the sticky at the top of the this forum, this is not the place to debate the validity of Relativity, and this thread is walking that line too finely.

I realise that to some of you this policy seems harsh, but allowing such debates generally leads down a slippery slope. They are seen as an open invite for anyone with a gripe against Relativity to put their two cents in. Since many of these gripes are based on misinformation, we are forced to rebut the same arguments over and over again. Either that, or the mentors have to go through the thread and prune it. In which case, some people will feel that they have been unfairly targeted for pruning.

I personally don't have enough time to baby sit that closely.