1. Originally Posted by James R
... To detect a photon means to absorb it, so your $100 is quite safe. Once a photon is detected, it is no longer "in transit" - it has been absorbed by the detector. ... That is true but does not mean you can not demonstrate photon is in transit at finite speed. I doubt if I will collect the$100, but perhaps you will back your, I think, false conclusion that their transit can not be demonstrated with a side bet?

2. Originally Posted by CptBork
In fact, considering the laws of force and acceleration as revised by Special Relativity is one of the central arguments leading to $E=mc^2$...
That is interesting. Do you have a link about it? As I guessed earlier before reaching this point in my progress forward we have no disagreement except what all is included in SR. For me acceleration is not as not any such term in the SR equations.

Perhaps an analogy will make our difference clear:

I say:
"RPT (regular polygon theory) cannot be applied to circles. And offer as support that there is not even any radius of curvature in RPT.

You say:
Yes it can. You simply take RPs with ever greater number of sides and in the limit you have the circumference of a circle calculated.

That is correct but you have used a limiting approach which is NOT part of RPT. Again I tell you there is no radius of curvature in any equation of RPT (or acceleration in the SRT equations).

SUMMARY: We agree on the RPT math (or physic of SRT) but have a semantic dispute as to what is RPT (or SRT). I am the purist stating that SR is only what is in the SR equations. You are the pragmatist saying RPT (or SRT) includes everything thing that can be described by RPT (or SRT) such as the circumference of a circle (or accelerating frames) via standard math techniques.

But again I would like to know how E =mc^2 falls out of SRT (even extended via some limiting process )

Also as you are probably more 35 years up to date than I am, is my memory false on following?

I seem to recall back in my graduate school that James R's two postulates as foundation of SR can be reduced to just his (1) Physics is same in all inertial frames if one applies this to make two observers in frames A & C who at t=0 are collocated notice their also collocated flash of light at t = 0 expands in a spherical shape for both.

I seem to recall deriving the equations of SR from that alone. The value of C comes easily for the vacuum permeability and dialectic constant if light is Maxwell's EM waves.
Originally Posted by CptBork
Again, there's no problem with treating accelerations in SR as long as they're not being caused by gravity....
I'll take your word for this but thought that locally one can not tell gravity from an acceleration, so find this strange.

3. I finally got back to your two granite blocks:
Originally Posted by Quantum Quack
{post 236}...time dilation could be and most probably is a product of inertia and it is the object that has operated against inertia that has suffered accordingly. ... So the SR derived ability to simply switch frames in my opinion is seriously neglectful of the universal reality, in particular to inertia. ... Time dilation is caused by the accelleration/velocity interacting with all obejcts of matter universally including that of the other observer but it is only the observer that under goes change [accelleration] that has physical reason for dilation [the fight against inertia]. The other observer has none. ...
One needs more than speculation to make valid assertions when they conflict with accepted POV. Even MacM does not think the time dilation is directly due to the acceleration or is concerned with inertial. I.e. massive clock equally accelerated to V with a light one does not have more time dilation, TD, wrt to clocks still at rest at the launch pad.

The “physical cause” of TD is much more related to the fact that ANY measurement of TD needs conceptually a time period defined by a “start” and “stop” event/ signals. One and only one of which can be collocated in both frames at t=0 (or t = 10,000) whatever they mutually agree to set their clocks to. Let’s say it is the Start accumulation event that are side by side for both frames. The other stop event will be widely separated in the two frames even if they are exactly where the start event was in the frame of the accumulators. Problem is not that we must correct for signal delays as we can - problem is much more deep than that.

Each observer can correctly claim the other cheated and let his accumulator count his clock ticks too long (to compensate for it slower tick rate of the clock moving wrt to him). That explains how the other guy’s accumulater registered the same number of ticks. I.e. only the start (or the stop, but not both) event can be simultaneous in both frames. Note there is nothing here about the mass of the accumulators, the clocks, or about their inertia.

Surely you will agree that just by gluing a light clock to a massive one will not make them tick at the same rate if they were not before being joined due to their different inertial as you suggest. I.e. your suggestion that inertia or the resistance it gives to acceleration is an important determinate of TD is simply false.

4. Originally Posted by Billy T
That is true but does not mean you can not demonstrate photon is in transit at finite speed.

I doubt if I will collect the $100, but perhaps you will back your, I think, false conclusion that their transit can not be demonstrated with a side bet? If I understand what you have suggested may be evidence then you are certainly the closest any one has been for over three years and hundreds of posts in many forums, trying to find such evidence and most importantly you are able as JamesR is also to understand the issue. In three years most response has been total incomprehension of what is being asked. So congrats....so far, are in order.....but a while yet to the$100 usd....

5. Originally Posted by Billy T
I finally got back to your two granite blocks: One needs more than speculation to make valid assertions when they conflict with accepted POV. Even MacM does not think the time dilation is directly due to the acceleration or is concerned with inertial. I.e. massive clock equally accelerated to V with a light one does not have more time dilation, TD, wrt to clocks still at rest at the launch pad.

The “physical cause” of TD is much more related to the fact that ANY measurement of TD needs conceptually a time period defined by a “start” and “stop” event/ signals. One and only one of which can be collocated in both frames at t=0 (or t = 10,000) whatever they mutually agree to set their clocks to. Let’s say it is the Start accumulation event that are side by side for both frames. The other stop event will be widely separated in the two frames even if they are exactly where the start event was in the frame of the accumulators. Problem is not that we must correct for signal delays as we can - problem is much more deep than that.

Each observer can correctly claim the other cheated and let his accumulator count his clock ticks too long (to compensate for it slower tick rate of the clock moving wrt to him). That explains how the other guy’s accumulater registered the same number of ticks. I.e. only the start (or the stop, but not both) event can be simultaneous in both frames. Note there is nothing here about the mass of the accumulators, the clocks, or about their inertia.

Surely you will agree that just by gluing a light clock to a massive one will not make them tick at the same rate if they were not before being joined due to their different inertial as you suggest. I.e. your suggestion that inertia or the resistance it gives to acceleration is an important determinate of TD is simply false.
I understand the general guist of what you are saying.
However I wonder why SRT does not consider acceleration in the same way it considers velocity regarding the issue of being able to grant the other observer all the velocity and TD....why not also grant the other observer with all the acceleration as well.
also in the two observer rocket scenario posted there was never the presumption of instantaneous acceleration. [ just didn't bother including duration in the details as it seemed irrelevant to the issue at hand.]

6. Billy T;
I finally got back to your two granite blocks: One needs more than speculation to make valid assertions when they conflict with accepted POV. Even MacM does not think the time dilation is directly due to the acceleration or is concerned with inertial. I.e. massive clock equally accelerated to V with a light one does not have more time dilation, TD, wrt to clocks still at rest at the launch pad.
A change in tick rates must be due to some causation yes?

The only change that has occurred between the two observers is accelleration of one observer?
Is it it not logical to conclude that the change in tick rates is dependant on the only change in causation available?
After all the the only change to the situation is in fact accelleration leading to a change in relative v.
That relative v of value is only possible by what? well...the answer can only be a phase of accelleration. [ other wise relative v is impossible from a oposition of zero relative v.]
As the only aspect that works against inertia is accelleration, as velocity itself is "inertia neutral" IMO one can conclude that it is acceleration and the shift in velocity effecting the universe at large that is primarilly the causation of time dilation.

Is this not a sound logical use of the information given?

7. Originally Posted by CptBork
And yet you complain when people throw around Einstein's name in order to dismiss you without considering any of your own arguments. You're doing the same thing here with me, and it just reflects on your desperation to be seen as correct. Go ahead, I challenge you to refute any of the points I made in my last reply. I pointed out some very basic fallacies in your reasoning and understanding of relativity, so since you're so touchy about being told you haven't studied the subject, please feel free to prove me wrong.

Tell me what's wrong with my simple SR solution to the twins paradox, since you claim Einstein needed to invent GR to solve this specific problem. What aspect of this solution is so inconsistent with relativity that you can dismiss it in one sentence as irrelevant babble and dogma? If you just came here to rant about why you personally dislike relativity and to dismiss anyone who refutes you as a brainwashed lackey, then there are more appropriate subforums where you could have posted your rant. This place is for serious physics debate and discussion including, where necessary, details.
Please cite the post # where you gave a non-GR solution to the Twins. I'll have ago at rebuttal.

8. Originally Posted by Billy T
I am not denying -only asking you for even one formula of SR where the acceleration even appears.

I have been busy so have not gone to your "evidence link." Also because the last one you sent me to a link, it was just an Email one guy sent to another.

I'm still waiting for real evidence that standard* SR uses acceleration - namely an equation with place to insert acceleration of something into the equation.

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*I understand that your version of SR does - infact requires one of two clocks to accelerate away form your "common rest frame."

9. Originally Posted by CptBork
Billy, just to let you know, SR is fully equipped to handle any acceleration as long as it's not caused by gravity. If you know a rocket ship's position or acceleration or velocity as a function of time, that's really all you need to describe all the relativistic effects. Accelerations are handled in SR by setting up a series of reference frames moving at different velocities, so that at any given moment the rocket ship or whatever may be considered at rest in one of these frames, and then the calculations for that brief instant of time can be done from there before being converted back into the original frame.
It is in fact an integration process just as I stated. Thanks.

10. Originally Posted by Billy T
Yes you have as no longer claim the both procedures you agreed to in your post 93 are correct. I.e. after my post 118 showing they give mutually self contradictory results, you said that both you and SR do not know how to compute Time Dilations correctly. Before post 118 you told how to correctly compute time dilations.
False. I have only shown that mere relative velocity fails and actual velocity (which is how SR is currently applied) is correct; except it (and absolute motion) still fail if you begin to look past the first acceleration.

SR only becomes correct if you arbitrarily tell it the clock is returning to a prior rest reference and give it a vector to increase not decrease with relative velocity.

11. Originally Posted by Billy T
At 291 I found:
I gave a test design with supersonic jet flying at constant altitude (for same transit delays of the start and stop pulses sent to the accumulator in the jet) over two well synchronized ground clocks (one on US east coast and other on the west coast) and other details such as pulse code timing patterns in the transmission to the plane, which can easily tell time to 0.001 micro second resolutions. So a test is possible despite what MacM says.
You don't seem to understand what isn't supportable by test emperical data. What is not testable is the view that from the jet airplane the gournd clocks are physically dilated.

12. Originally Posted by CptBork
As far as acceleration in the twins paradox goes, there's no real need to consider it. If the spacefaring twin has a long journey (i.e. 20 years as seen from Earth) at speeds close to c, and by comparison their acceleration only takes a day or so, it makes almost no difference whatsoever to the end result. So one twin ages half as much as the other if the acceleration is instant, and you give or take at the very most a day depending on how they accelerated during that one day... big whoop.
You have missed the point entirely. The point of the twins is that the stay at home twin has shared a relative veliocty over the enitre test period including incremental velocity changes during acceleration of the traveling twin.

Baded on the relative velocity view therefore the stay atvhome twin is dilated (aging more slowly) than the stay at home twin from the traveling twins frame of reference.

That produces what is called reciprocity which means two clocks must tick slower than each other at the same time. By including GR and claiming that the traveling twin switched frames (accelerated and had actual velocity not merely relative velocity) the symmetry is broken and SR correctly computes the traveling twins age.

But you must recognize that by doing that you are no longer applying relative velocity between clocks to SR. You are in fact applying LR not SR and trying to give credit to Einstein not Lorentz.

If this was your solution to Twins withoutv GR I'm afraid you fall considerably short.

13. Originally Posted by MacM
By including GR and claiming that the traveling twin switched frames (accelerated and had actual velocity not merely relative velocity) the symmetry is broken and SR correctly computes the traveling twins age.
There is no GR involved there; it's all SR.

What is true is that you have to use all of SR to do the computation, not just the parts having to do with inertial frames, since one of the rest frames in question is non-inertial during parts of the thought-experiment. But SR has no problem with this: if the spacetime in question is flat, SR covers all cases.

14. Ok, QQ, for $100, here is how to both measure the length of a photon and demonstrate that it really is traveling between the lamp and the detector although instead of the detector illustrated below I uses either (1) a small (large postage stamp size is ok) photograph film (well shield form any light not nearly the same paths as shown) and very long time exposure* or (2) just a piece of white paper as a screen when the lamp is bright. You can imagine this Film or Screen (hereafter called FS but only one used at a time) is flat against the bottom edge of the drawing (below the detector shown , which has been removed to not cast any shadow on the FS. http://upload.wikimedia.org/wikipedi...ter.svg/305px- if that image not here go to: http://en.wikipedia.org/wiki/File:Interferometer.svg I said “nearly” the same path as I do not want the infinitely thin rays shown in red, but relatively narrow “fans of light” replacing each of the two ray paths shown. I will call these two paths T (for the one using the Top mirror) and the other “R” as it is using the Right mirror. “Relatively narrow” means that if I block either path T or R, no interference pattern is formed on the FS. There will be just a nearly uniformly illuminated screen or cause a nearly uniform darking of the film instead of an interference pattern somewhat like: | | | | | | | | | but of course the intensity is not this “all or nothing” contrast as I must represent it here due to limits of my “typed drawing.” The intensity pattern is sort of like {sin(x) + 1}/2 where I have “normalized” to make the peak intensity of the pattern unity and the least intensity in the pattern zero but we need not be much concerned with the exact shape of the intensity distribution along the “x-axis.” (which is horizontal in my typed picture of the interference pattern). Now I need to name the nine lines of my illustration pattern. They are: -4,-3,-2,-1, 0,1,2,3,4. Line zero has exactly the same length for paths T and R. It is where there is constructive interference for all wave lengths of light and thus sometimes called the “white light fringe” or white light line of the pattern. I will be more concerned with it that the others. The pattern lines (-1) and 1 are where paths lengths T and R differ by one wavelength also but they will moves wrt the white light fringe, 0. I.e. if made with long wave red light they are farther from 0 than if made with blue light. This is one way you can tell which is the 0 line without trying to measure and make the paths T and R exactly equal (or differ by a multiple of half wavelengths – more on this in third paragraph below) – an essentially impossible task to the accuracy required. Now if I were to slowly move only mirror R further away from the half silvered mirror keeping it always parallel to its self (zero rotation as it moves) the 0 peak will cease to be unity strong and the previous perfect nulls will start to get light. When I have moved it ¼ of a wavelength the intensity pattern will be like: {cos(x) + 1}/2. I.e. the peaks will be where the nulls were and conversely the new nulls are where the peaks were. Thus the location of the white light fringe, 0, is now a null due to perfect destructive interference. I.e. path R = path T + half a wavelength. (The ¼ wavelength is traveled to and from the mirror for a ½ wavelength extra.) This alone should show that something with a wavelength is traveling between the lamp and the screen. but I will continue on to describe how I learn how long this energy thing (called a photon) is: If I continue to move mirror R further away when the total distance moved is ½ wave length, 0 point on FS is again a bright peak. This alternation between null and peak repeats for several thousand multiples of ½ wavelengths without noticeable difference in the pattern but if carefully observed the nulls are no longer totally without light and more difficult to measure/ observe, the peaks no longer have the full unity strength. The total energy reaching FS is not changing – the “nulls” are filling in and the peaks are being reduced. Eventually in the case of I measured when the mirror R had moved about 15 cm (path difference of 30 cm) the screen was uniformly illuminated – no longer with even a hint of either constructive or destructive interference. Now to explain this I need to switch to film and very long exposures (weeks?) with very weak light – much lower than one can reliably detect with even the “dark adapted eye” looking straight at the lamp. So weak a light that the quantized packets of energy (Einstein got his Noble prize related to this quantization of the photo-electic effect with similar very weak lights.) rarely ever existing two at the same time. Most (>90%) of the time, not even one exists. After a week or so of exposing the film (very cold for reasons I will not go into much except to note that the same crystal in the film must have a second photon hit it before the effect of the first is lost to diffusion to be partially stabilized) and developing it, we still find that the interference pattern is recorded in the film. This confirms the quantum mechanical theory prediction (“nonsense” to us humans) that each photon actually travels via both paths. I.e. when the light was strong (millions of photon existing at the same time) and I was looking at the screen, each photon was actually interfering with its self that had traveled the other path. – not interfering with any of the other million of photons. When you stop to think about it – you already knew that. A perfect interference null in waves is only possible if the peaks are exactly 180 out of phase with the nulls of the wave. For example in analogy, if you have hundreds of loud speakers each driven by separate amplifiers all producing exactly the same 1000 Hz sound wave, but not “phase locked” together, then nowhere in the room is there anything even resembling silence – perfect cancellation. If you turn off all but one sound source there are hundreds of locations in the room where perfect cancellation is occurring. Without any phase locking of the various individual radiators, the phase of each wave is random – we call this an “incoherent” source. Most light waves (all except lasers or laser driven sources) are incoherent. All simple lamps radiate as incoherent sources. Each radiating atom is just doing its thing independently of all the others. Thus, when I see a perfect null on the screen with millions of photons falling on it elsewhere, I know that QM’s perdiction and the experiment with very weak light / long exposure is also the strange for humans to understand self interference of each photon with its self. I.e. each photon even when millions of other do exist is going to the screen via both paths and of course is coherent or in phase with its self. Now I will “type draw” one photon interfering in condition to interfere with its self when it gets to the screen. I show the “part” that travels via the T & R paths one above the other now: First when the path lengths T and R are equal: T:/\/\/\/\/\/\/\/\/\/\/\/\ R:/\/\/\/\/\/\/\/\/\/\/\/\ At the screen 0, this photon helps make the peak of the light pattern (constructive interference with itself). Now when the path lengths differ by half a wavelength: (mirror R moved ¼ wave length away): T:/\/\/\/\/\/\/\/\/\/\/\/\ R:\/\/\/\/\/\/\/\/\/\/\/\/ At the screen 0, the white light location, they add to zero, to make a null instead of filling it in. Now I draw what is the condition when the path difference between T & R paths is about half the length of the photon (Ignore the …… they are just there as Sciforum would compress multiple spaces down to one if I did not put something there to hold the space against the “compression happy” sciforum computer.) Also imagine that the screen is to the right. I.e. the “right end” of the photon is its “head” and arrives at the screen first. Remember the R path is a little longer now so that “R part’s head” will arrive at the screen a little after the “T parts head” is already beginning to interact / die in the screen (This is all being stated in human terms, trying to describe a QM type of event and not to be taken too literally.) T:……................/\/\/\/\/\/\/\/\/\/\/\/\ R:/\/\/\/\/\/\/\/\/\/\/\/\ With front half of the T part of the photon (foolish human terms) dead in screen the interference is only half as effective. I.e. the “tail of the T part” and the “head of the R” part are arriving at the screen together and can interfere. But the tail part of the R part arrives alone. This happens for all of the photons and so the stastical average effect makes something like this intensity pattern I(x) on the screen: Intrensity function, I (x) = [{sin(x) + 1}/4]+ 1/4 Note: When sin(x) = 1 the intensity peak is about [{1+1}/4] +1/4 = 0.75 (no longer the old peak = 1.0 of equal path lengths.) When sin(x) = -1 the first term is zero so, Intensity, I = ¼ (no longer the old perfect null of 0.0) With some more movement of the R mirror away the photon parts look like (if one could see them without killing them): T:…….....…………........……..……./\/\/\/\/\/\/\/\/\/\/\/\ R:/\/\/\/\/\/\/\/\/\/\/\/\ And the I(x) function is just a constant. I.e. I = 0.5 or in words, there is no interference pattern left – just a uniformly lighting of the screen. Never in any of these conditions has any energy been lost. The interference is only changing how it is distributed over the screen. With the lamp I was using , the screen interference pattern faded out as R move away and was undetectable when R had moved about 15 cm. I hope you now understand why I say the photons I was working with from my lamp were about 30 cm long. SUMMARY: Not only have I shown that there is something moving between the lamp and the screen, (the$100 prize requirement) but I have told you how long this “something” was and that it has something of a “split personality” characteristic that defies human understanding, which allows this one thing to travel over two widely separated paths! Also defying human understanding, it is “wave like” in that it has a wave length (four times the tiny movement which changes the screen intensity at the 0 position from null to peak),yet when it gets to the photographic film all of its energy is absorbed in one very tiny crystal* of the film emulsion! (or as Einstein discussed for the Nobel prize, ejects an electron, which is even smaller with at times it full energy (less what is called the “surface work function” but I will not explain that now as this post is already too long.)

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*See: http://en.wikipedia.org/wiki/Reciprocity_failure
“At low light levels, i.e. few photons per unit time, photons impinge upon each grain relatively infrequently; if the four photons required arrive over a long enough interval, the partial change due to the first one or two are not stable enough to survive before enough photons arrive to make a permanent latent image center.”

The decay of the effect of the first photon produced is by thermal mechanism, so keeping the film very cold can “restore reciprocity” that would other wise never let the slowly arriving photos cause and lasting or “quasi stable” effect which the “developer” could spread to the entire crystal later.

The photographic “reciprocity law” state that if you double the exposure time you can take a still picture in half the light intensity (Or half the lens opening). The failure of this law occurs with very low light levels (unless you really cool down the film, but then you must have very dry air – typically not even air but a “dry nitrogen” atmosphere contacting the film.)

PS
Wiki's drawing near top of this post is OK with a coherent light source (a laser no doubt) but a laser will only make bright and dark "spot fringes" that modulate the electronic detector’s output. – It will not make a 2D interference pattern like my 9 lines if as shown in Wiki's drawing which I stole.**

Also note that the half silvered mirror in Wiki's drawing is not exactly at 45 degrees to the other mirrors. This is why the beams returning to it from mirrors T & R do not exactly re-trace the paths of the beams coming to these mirrors from the half silvered. That separation of beams faciliates understanding of the drawing and will work, but makes minor complications when I move mirror R ,so as I used it the half silvered mirror is exactly at 45 degrees to both T & R mirrors. Then the beam using R returns from on exactly the same path it came to R on and moving R by 1/4 wave length then exactly increases the path that beam travels "extra" by 1/2 wave length as stated in my prior discussion, with being as detailed as here.

To do this replace that light source with an extended in 2D one behind a frosted glass and in front of the frosted glass there is a lens, which images the plane of the frosted glass on to the FS. Then you can get the interference pattern (like the nine lines I drew instead of just the laser’s spot.) It does not make any difference as each photon interferes with itself whether or not the light source is coherent or not but to get the 2D interference pattern you must have a 2D source imaged on the screen. The frosted glass is effectively the source you are using. Wiki tries, but often does not get things quite right.

** Where do you live QQ? Perhaps you buy me drink and dinner and give the rest to Wiki in payment for things I steal from them like the drawing.

There is no GR involved there; it's all SR.

What is true is that you have to use all of SR to do the computation, not just the parts having to do with inertial frames, since one of the rest frames in question is non-inertial during parts of the thought-experiment. But SR has no problem with this: if the spacetime in question is flat, SR covers all cases.
Not sure where you are coming from or headed but there are a couple of clarifications needed here. But since what I said was Einstein employed GR to resovle the Twin Paradox is true.

1 - Non-inertial is GR even though SR can handle acceleration.

2 - Periods of acceleration must be integrated into the total computation to find the final dilation in terms of less accumulated time.

3 - You are only partially technically correct.

************************************************** ********

Starting with Paul Langevin in 1911, there have been numerous explanations of this paradox, all based upon there being no contradiction because there is no symmetry — only one twin has undergone acceleration and deceleration, thus differentiating the two cases. One version of the asymmetry argument made by Max von Laue in 1913 is that the traveling twin uses two inertial frames: one on the way up and the other on the way down. So switching frames is the cause of the difference, not acceleration per se.[1]

Other explanations account for the effects of acceleration. Einstein, Born and Møller invoked gravitational time dilation to explain the aging based upon the effects of acceleration.

************************************************** ****

4 - I posted in response to BS from CptBork. He made the error of making a couple of aggressive initial posts implying "People that have not studied SR and don't understand.....", etc. ,etc, implying that he has and does.

But his most recent post shows without doubt he does not understand. His claim that making the acceleration period short in comparison to the inertial velocity duration resolves the issue is just plain nonsense.

CptBork doesn't know what he is talking about.

Time dilation is a matter of switching frames and it does not matter what period or duration such changes take place. Such durations only change the integrated total affect but it is the switched frames however achieved that is the root cause.

5 - Having said that and having used the preferrred language of "Switched Frames" I must hasten to point out that you can only switch frames if you accelerate. It is not the acceleration but the induced velocity change from acceleration that is the cause.

6 - Having said that and posted the above link I also point out that Einstein applied the Einstein Equivelence Principle and used GR as a part of the the solution.

So while you can ignore how you switched frames and claim GR isn't involved, technically you are would be correct. GR generally deals with natural gravity; however - GR is also associated with non-inertial frames, rotation and acceleration and acceleration is required to switch frames. So to refer to it in this case is perfectly correct also.

Einstein agrees with me not you so back off.

16. Originally Posted by MacM
Please cite the post # where you gave a non-GR solution to the Twins. I'll have ago at rebuttal.
It's post #41, but of course from the thread I previously linked, not this one. Here's a direct link to the individual post, without the rest of the thread. Very much looking forward to your rebuttal.

Originally Posted by MacM
Baded on the relative velocity view therefore the stay atvhome twin is dilated (aging more slowly) than the stay at home twin from the traveling twins frame of reference.

That produces what is called reciprocity which means two clocks must tick slower than each other at the same time. By including GR and claiming that the traveling twin switched frames (accelerated and had actual velocity not merely relative velocity) the symmetry is broken and SR correctly computes the traveling twins age.
This is not true in the slightest. The Lorentz transformations involve not just time dilations, but also shifts in the simultaneity of time in different places. If one observer sets up a bunch of (relatively) stationary clocks around the universe and they all tick at the same rate and time according to this observer, they will then be ticking at equal (dilated) rates, but not ticking simultaneously, according to other observers who are in relative motion with respect to these clocks. The simultaneity of events is a relative concept, and observers are allowed to disagree on the time ordering of events as long as the events are far enough apart in space that a light beam from one couldn't influence before it takes place (the speed of light limit prevents time paradoxes from occurring).

Go ahead and look at the example where I use simple SR basics to give a nice, clean solution to the twins paradox that works from either twin's POV to get the same answer. The $\frac{vx/c^2}{sqrt{1-v^2/c^2}}$ term is what leads to simultaneity effects. It causes the Earth's clock to zoom forward in time relative to the astronaut's clock as soon as the astronaut reverses direction, and the result overcomes the dilation part of the transformation. As long as you always work in inertial coordinate frames, you are forced to specify a clear scheme for who is accelerating, by how much and at what times, which then automatically sets these values for all other reference frames. Absolutely no GR needed whatsoever, although it's a popular misconception that GR has to be invoked. Nope, Einstein had it all figured out at least 10 years before GR was even published.

Originally Posted by MacM
If this was your solution to Twins withoutv GR I'm afraid you fall considerably short.
Well it wasn't, so now you're just going to have to read the argument and show me what's wrong with my calculations.

Note: In that post, I talked about simultaneity at the end and commented that Bob would see Albert's clocks ticking faster, I should have written the opposite (slower). Not of any relevance to my discussion about the actual twins paradox and the calculations therein.

17. BillyT, thanks for the effort you went to. I appreciate it.
I am due at a Rotary meeting with an over night stop over so I shall hopefully get a chance to get into your post better when I get back to my desk.

However at first glance I get the impression that in the first portion of your exposition you are referring to typical interferometer usage and what that implies? If so I have grave doubts whether that is sufficient evidence to avoid an alternative explanation for the light effect.

Any ways thanks again and to be perfectly honest, if your exposition proves that a photon travels from A to B across vacummuous space I will be more than happy to part with my \$100 usd....but we shall see...

Obviously there is already a significant disadvantage to your presentation and that is it is performed in an ambient medium [ air or nitrogen or what ever as it doesn't matter ] so the need to show light transiting a vacuum is still a concern. However if one can conclude that satisfactory evidence is possible even in an ambient medium such as air we may side step that requirement.
It could be proposed for example that light energy "jumps" from particle to particle across the space in between instantaneously, with out traveling [in a medium such as glass - optic fibre or water or air or anything of mass.] the delay in time being experienced due to distance, being a mass inertia effect*** and not a time to transit effect. So ruling out mass as the medium for transit is very necessary. It is the space that is vacant between particles of mass, the vacuum and the void that is normally inhabited only by photons and em that is in question.

any ways When I get back from my meeting I shall give it some deeper consideration and post accordingly.

*** the invariant speed of light could actualy be a significant aspect of "inertia" but is lost to us because we put it the photon outside of mass instead of inside mass. [ which is where we can only observe it any way...]

18. Originally Posted by MacM
1 - Non-inertial is GR even though SR can handle acceleration.

[...]

however - GR is also associated with non-inertial frames, rotation and acceleration and acceleration is required to switch frames.
No, SR handles all of those types of frames just fine, so long as curved spacetime (i.e., gravity) is not involved.

19. Originally Posted by CptBork
It's post #41, but of course from the thread I previously linked, not this one. Here's a direct link to the individual post, without the rest of the thread. Very much looking forward to your rebuttal.
Originally Posted by CptBork
It's post #41***********Extract of CptBork Referenced Post **********
Now for the classic, special relativistic solution to the Twins Paradox:

Suppose two twins, Bob and Albert, start off on planet Earth. They synchronize their watches, and then Bob takes off in a spacecraft headed at velocity towards a deep space navigational beacon which has been placed a distance from the Earth along the positive x-axis. The navigational beacon may be taken to be stationary with respect to Earth for this example, as having a moving beacon still leads to the same result.

From Bob's point of view:
Bob takes off from Earth and almost instantaneously accelerates to velocity with respect to Earth. The time it takes Bob to reach the navigational beacon is measured on Bob's watch as , and this watch measures the duration of the return trip as . Applying the Lorentz transformations, Bob argues that the corresponding travel times on Albert's watch will be

and

.

Adding these times together, Bob argues that his watch will measure a time for the total trip, whereas according to Bob's reasoning, Albert will measure a time on Albert's watch. Thus Bob argues that his twin, Albert, will have aged more than him at the conclusion of the trip.

1 - As noted to "take off" one must accelerate. Acceleration is non-inertial and is a GR function. Although as I have already stated acceleration can be handled by SR via integration.

2 - Acceleration induces a change in velocity. It is the shift in velocity that is the bases for time dilation.

3 - You till talk about what Bob "argues", "Reasons", "thinks", etc. I have repeatedly said that there is an "Illusion of Motion" and that each can percieve time dilation but that it is not physically real. The reality is that a clock is not altered by another observers morion creting relative velocity.

Originally Posted by CptBork
It's post #41*********Extract of CptBork Referenced Post********
From Albert's point of view:
Albert[b] sees[p/b] (or will later receive news by radio signal of) Bob's arrival at the navigational beacon at time as measured on Albert's watch. Albert then applies the Lorentz transformations and argues that Bob will measure the trip time as

Since the distance between Earth and the navigational beacon is defined from Albert's reference frame, we may write . Plugging this into the Lorentz transformation, we then find that

which agrees with Bob's calculations as performed from Bob's P.O.V.

Similarly, by applying the Lorentz transformations for Bob's return trip, Albert calculates that while his own watch records as the time taken to return to Earth, Bob's watch will record this travel time as

Notice that the signs on and have been reversed from positive to negative, because now Bob is travelling in the opposite direction with the opposite velocity. Substituting , we end up with

so we see that again Albert's calculations agree with Bob's measurements.

Now we add up the total trip time Albert measures and the time he calculates should pass on Bob's watch, and with a tiny bit of algebraic manipulation, we end up with the relationship just as was calculated from Bob's P.O.V.

So in conclusion, we see that Bob and Albert both agree that Bob returns from his trip having aged less than Albert, and the same result is mathematically obtained from either twin's point of view. The key to resolving the Paradox of the Twins is to understand that the Lorentz transformations don't just involve space and time dilations, but that the concept of simultaneity itself is also a relative concept; i.e. if Albert sets up a bunch of clocks in space all synchronized to tick at the same rate at the same time by the same amount, Bob will also see the clocks all ticking at the same rate (albeit the ticks will appear faster than what Albert sees), but the actual readings on each clock will appear to be different, as if they weren't properly synchronized at the start.
1 - As I have noted previously and James R tried to deny it you direct SR to change sign -L to +L . That is it is no longer just a matter of relative velocity but of specific vector. That is you are instituting an absolute motion concept by selecting the return path to a prior rest reference and are ignoring the relative velocity affect to the navigation beacon.

Reference to the navigation beacon Bob must be dilating and at the same time increasing tick rate to return to Albert's frame. Nothing wrong with your math but plently wrong with the concept which ignores relative velocity when it suits and asserts it when you wants.

2 - You still want to interject "appear", "sees", etc, What observers "Percieve", See", etc is not at issue. What is at issue the the ultimate physical condition of clocks when compared in a common rest frame subsequent to having had relative veloicty, not while relative veloictyv exists. That leads to what observers "See" but not what becomes emperically supported. That is the issue.
************************************************** *****

Originally Posted by CptBork
This is not true in the slightest. The Lorentz transformations involve not just time dilations, but also shifts in the simultaneity of time in different places. If one observer sets up a bunch of (relatively) stationary clocks around the universe and they all tick at the same rate and time according to this observer, they will then be ticking at equal (dilated) rates, but not ticking simultaneously, according to other observers who are in relative motion with respect to these clocks. The simultaneity of events is a relative concept, and observers are allowed to disagree on the time ordering of events as long as the events are far enough apart in space that a light beam from one couldn't influence before it takes place (the speed of light limit prevents time paradoxes from occurring).
You are still discussing affect (Illusions) of motion on perception, not physical actual clock conditions.

Originally Posted by CptBork
Go ahead and look at the example where I use simple SR basics to give a nice, clean solution to the twins paradox that works from either twin's POV to get the same answer. The $\frac{vx/c^2}{sqrt{1-v^2/c^2}}$ term is what leads to simultaneity effects. It causes the Earth's clock to zoom forward in time relative to the astronaut's clock as soon as the astronaut reverses direction, and the result overcomes the dilation part of the transformation. As long as you always work in inertial coordinate frames, you are forced to specify a clear scheme for who is accelerating, by how much and at what times, which then automatically sets these values for all other reference frames. Absolutely no GR needed whatsoever, although it's a popular misconception that GR has to be invoked. Nope, Einstein had it all figured out at least 10 years before GR was even published.
1 - Zoom forward, change direction? You are employing absolute motion not mere relative motion. This has been my contention all along.

2 - You consider who is accelerating - i.e. who has actual motion not mere relative velocity. That is precisely what I have claimed. Acceleration is a non-inertial frame and that is generally refered to as GR so you are considering GR when you interject acceleration. You are also now working in a absolute motion system not merely relative velocity.

Originally Posted by CptBork
Well it wasn't, so now you're just going to have to read the argument and show me what's wrong with my calculations.
As I said nothing wrong with your calculation but with your claim that it is mere relative velocity and not a function of acceleration or absolute motion. I have repeatedly said that as applied SR works but that to do so ignores the failure of the relative velocity view.

Amazingly you have said nothing I have not already stated. You have not changed anything. You repeat what I've said and try to make it appear as contridictary.

The only thing you (and others) keep doing is adding what observers in relative motion "See" and I have made it abundantly clear that is not at issue.

Your attempt to ignore that to switch frames you must accelerate and that acceleration is non-inertial is curious. It is the shift in veloicty (energy in absolute terms) that appears to affect clocks.

The issue is that SR claims that relative velocity causes time dilation. That is simply false asnd has been shown to be false by every test ever done.

Mere relative velocity leads to reciprocity and there is no emperical data to support that view. It has never been tested and would appear to be untestable. If untestable it falsifies SR as valid theory.

Including "Who accelerated" in your calculations switches from SR to LR an absolute system.

With respect to Einstein applying GR as a part of the Twin solution I hope you read my post with the link. I'm correct and you are wrong. Not sure what your problem is since I have said SR can handle acceleration.

No, SR handles all of those types of frames just fine, so long as curved spacetime (i.e., gravity) is not involved.
You are merely repeating what I have said. You can make it appear that you are correcting me but you aren't. I have already stated several times that SR can handle acceleration.