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

[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]

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 transferred 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 transferred 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 transferred 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 Earth's 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 Earth's 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'

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?

 

[quantumdude]

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.



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[Nereid]

Thanks for the clarifications yogi.

What is 'the inflow theory'?

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