# Thread: Kenhughes' imagination of SR

1. Can anyone explain to me how time can be observed as slow from both the moving and stationary reference frames? Please don't give me more of the mainstream arguments, I understand those. Please explain why you would not observe a transverse doppler BLUEshift from the moving frame with the SR prediction of REDshift looking from the stationary frame.

2.

3. The answer as to why time is dilated regardless of what frame you start with is that there is no stationary frame, except by our choice of starting frame, and two frames assign different things to be simultaneous, given their own system of coordinates. But you knew that.

I'm not sure that I understand your question, though. In SR, one sees a redshift when one is moving towards something emitting light and a blueshift when one is moving away from something emitting light. One cannot receive a blueshift or a redshift in light when one is the source of that light.

4. Hi PhysBang,

Firstly, thank you for responding to my question.

Yes, I did know that, at least I knew that is the mainstream explanation, but thanks anyway.

Understanding my question lies in the word;- "TRANSVERSE".

1. I deliberately chose the example of instantaneous observation from thestationary frame, looking at right angles to the path of motion. The moving clock is passing by “overhead”, if you like, at the instant the observation is made. That way there is no red or blue shift due to the motion, but only the transverse Doppler shift due to the TIME DILATION of motion given by t =ROOT(1-v,squared/c,squared). This is very small of course at low speeds, but nevertheless it is the prediction for time dilation from Special Relativity.

2. I am not referring to observing one's own light source. I am referring to observing the stationary source from the moving frame. Time definitely IS dilated in the moving frame relative to the stationary frame and so the moving clock really DOES go slower. This was proven in 1971 by Hafele & Keating's atomic clocks. This difference in time rates takes account of the two frames first having synchronized clocks running at the same rate BEFORE the moving frame accelerated from rest. Special Relativity does NOT take this into account when it uses only geometry to predict reciprocity of observations. It ignores the initial conditions. As such it is naďve and incomplete.

This reality of relative time dilation therefore MUST result in a transverse Doppler BLUEshift when observing the stationary frame from the moving one, (Thestationary clock is faster). This is because any "shift" is equivalent to the time dilation between inertial frames. It is the same thing. This therefore proves that there is NO RECIPROCITY of time as observed between the two inertial frames. There is redshift in the moving frame, but a relative blueshift in the stationary frame, both equal and opposite in magnitude. This has to be what is observed.

Special Relativity is WRONG, or at least the accepted interpretation of it is wrong in predicting reciprocity of observations between inertial frames.

I know this puts the cat amongst the pigeons and there is bound to be emotional, knee jerk reactions from mainstreamers, but that's the way the cookiecrumbles I guess. They'll get used to the idea eventually.

If you want to know more, and there is indeed lots more, or anyone else forthat matter, my e-mail address is
kenhughes@aol.com

Unless of course, I am wrong. In which case would somebopdy please tell me where in the above reasoning?

5. Originally Posted by kenhughes
Understanding my question lies in the word;- "TRANSVERSE".

1. I deliberately chose the example of instantaneous observation from thestationary frame, looking at right angles to the path of motion. The moving clock is passing by “overhead”, if you like, at the instant the observation is made. That way there is no red or blue shift due to the motion, but only the transverse Doppler shift due to the TIME DILATION of motion given by t =ROOT(1-v,squared/c,squared). This is very small of course at low speeds, but nevertheless it is the prediction for time dilation from Special Relativity.
If the source of light is in motion relative to the absorber, regardless of any other spatial orientation, then we get the time dilation.
2. I am not referring to observing one's own light source. I am referring to observing the stationary source from the moving frame. Time definitely IS dilated in the moving frame relative to the stationary frame and so the moving clock really DOES go slower. This was proven in 1971 by Hafele & Keating's atomic clocks. This difference in time rates takes account of the two frames first having synchronized clocks running at the same rate BEFORE the moving frame accelerated from rest. Special Relativity does NOT take this into account when it uses only geometry to predict reciprocity of observations. It ignores the initial conditions. As such it is naďve and incomplete.
Special relativity assumes 1) that it is in principle possible to synchronize clocks at a distance, 2) certain results from mechanics and electrodynamics, and 3) certain preferences for the use of geometry and shows from this that it is not possible to keep clocks synchronized when those clocks are in motion relative to each other. This is a fundamental result based on geometry and the best case scenario in keeping clocks or any physical process synchronized. I'm not sure, outside of the general theory of relativity, that there could possibly be any initial conditions that could change the geometry of spacetime for all observers. It would take a theory that fits the available observations much better (e.g., general relativity) before one could take such a hypothetical problem seriously.

Given that special relativity both rests on the results of scientific inquiry (mechanics and electrodynamics) and explicitly sets out requirements for describing initial conditions, it seems wrong to say that it ignores initial conditions. It would take some significant argument, worthy of publication in a serious scientific or philosophical journal, to establish this.
This reality of relative time dilation therefore MUST result in a transverse Doppler BLUEshift when observing the stationary frame from the moving one, (Thestationary clock is faster). This is because any "shift" is equivalent to the time dilation between inertial frames. It is the same thing. This therefore proves that there is NO RECIPROCITY of time as observed between the two inertial frames. There is redshift in the moving frame, but a relative blueshift in the stationary frame, both equal and opposite in magnitude. This has to be what is observed.
In the reference frame of the lower clock, the passing clock is dilated. In the reference frame of the higher clock, the passing clock, in this case the lower clock, is dilated. A clock that moves first towards and then away from a light source will first see blueshift of that light and then see redshift of that light; this is the Doppler shift. Redshift due to time dilation is another, separate effect on that light that is not the Doppler shift.
Special Relativity is WRONG, or at least the accepted interpretation of it is wrong in predicting reciprocity of observations between inertial frames.

I know this puts the cat amongst the pigeons and there is bound to be emotional, knee jerk reactions from mainstreamers, but that's the way the cookiecrumbles I guess. They'll get used to the idea eventually.
If you can come up with a better theory that fits the facts or if you can demonstrate that special relativity is incorrect, you are welcome to your Nobel prize.

6. Hi PhysBamg,

Firstly, you should refrain from making sarcastic comments about Nobel prizes. It is not becoming of a professional attitude.
I suppose I may appear to have put myself on a pedestal by having the audacity to dissagree with SR, but I am not dissuaded by any attempts to knock me off it. This is human nature and is predictable. I am well prepared for it and even predicted it towards the end of my last response.
I have no delusions of grandeur about such things and I simply do genuinely dissagree unless someone can put me right. I have invited this and if an error in my logic can be presented I shall accept it with all humility. In the meantime, I still dissagree as you have not pursuaded me of any such error.

Secondly, you appear to have completely misunderstood the points I am making.

If the source of light is in motion relative to the absorber, regardless of any other spatial orientation, then we get the time dilation.
Correct, but you are simply repeating my agreement with SR on this point. You do not appear to understand that the transverse Doppler shift reflects this time dilation.

Special relativity assumes 1) that it is in principle possible to synchronize clocks at a distance, 2) certain results from mechanics and electrodynamics, and 3) certain preferences for the use of geometry and shows from this that it is not possible to keep clocks synchronized when those clocks are in motion relative to each other. This is a fundamental result based on geometry and the best case scenario in keeping clocks or any physical process synchronized. I'm not sure, outside of the general theory of relativity, that there could possibly be any initial conditions that could change the geometry of spacetime for all observers. It would take a theory that fits the available observations much better (e.g., general relativity) before one could take such a hypothetical problem seriously.

Given that special relativity both rests on the results of scientific inquiry (mechanics and electrodynamics) and explicitly sets out requirements for describing initial conditions, it seems wrong to say that it ignores initial conditions. It would take some significant argument, worthy of publication in a serious scientific or philosophical journal, to establish this.
I agree, but again I am not sure what point you are trying to make. I am simply saying that initially, the two clocks were synchronised on Earth, before one of them took off then flew far away and took a long run up to fly past overhead at speed. The moving clock is relatively slower than the Earthbound clock as it flies past. This is fully in accord with SR as you must agree. I am not proposing any change to the geometry of space-time outside of accepted theory.
I am asserting that because the moving clock is relatively slow, then the staionary clock is relatively fast and so one must observe blueshift when observing it from the moving frame.

Special Relativity takes velocity as purely relative and therefore argues the reciprocity of redshift from this purely geometric analysis. It takes no account of the common reference frame in which the clocks were, or would become, synchronised. It therefore DOES ignore initial conditions.

In the reference frame of the lower clock, the passing clock is dilated. In the reference frame of the higher clock, the passing clock, in this case the lower clock, is dilated. A clock that moves first towards and then away from a light source will first see blueshift of that light and then see redshift of that light; this is the Doppler shift. Redshift due to time dilation is another, separate effect on that light that is not the Doppler shift.
I shall refrain from using the terms "higher" and "lower". They only serve to confuse and "moving" and "stationary" should suffice.

We agree yet again that the moving clock is dilated, but you are resisting acknowledging that consequently, the stationary clock must be relatively faster. This relative time rate differential is fully in accordance with SR but it does expose a contradiction in the theory. You (and the mainstream), are hanging on grimly to the purely geometric analysis of SR in your statement that time is dilated in both frames. It is not the case and time is only dilated in the moving frame as SR itself predicts. The stationary clock carries on ticking at the same old rate. and SR contradicts itself with the assertion of temporal reciprocity. This is the core of my dissagreement.

If you can come up with a better theory that fits the facts or if you can demonstrate that special relativity is incorrect, you are welcome to your Nobel prize.
Firstly, let's see exactly what the "facts" are. It IS a fact that time dilates in the moving frame and we see experimental evidence of this. However, no one has yet carried out an experiment to see what the observations are from the moving frame. It is not yet an established fact that redshift is observed from the moving frame, only from the stationary frame.

Like all good "theories", or in this case, modifications to theories, a postulate must be capable of being disproved. So, I challenge the scientific community to disprove my assertions and carry out an experiment to measure the shift as observed from the moving frame. This should be possible with a fast fly-by of a known frequency light source past a light source of the same frequency in an inertially slower frame. I predict a blueshift of the light source as observed from the moving frame.

7. Oh no, not another "SR is wrong because there is no symmetrical time-dilation in the Hafele Keating Experiment" thread!

Time-dilation is symmetrical between inertial frames of reference.

The Hafele-Keating experiment is not comparing inertial frames of reference.

8. SpeedFreek,

I see you mock but provide no reasoning. That's good, very good. It means I've struck a nerve. It must be very frightening when someone shakes the very foundations of one's beliefs. Science is not based on beliefs though. It is based on sound theory and experimental evidence.

You state the SR "symmetrical" mantra very well, but that is all it is, a mantra. It is not a proven fact. If you seek proof, (either way), then you will have to wait for the results of the experiment I suggest. Until then, my hypothesis stands. Afterwards, you may have to eat your words.

The Hafele & Keating experiment is indeed comparing inertial frames. The time dilation of the moving clock is due to the fact that it moved. Pretty obvious really. (You cannot argue that because it went around in a circle then it was not inertial. How big a circle do you think we need to make it inertial?)

9. Originally Posted by kenhughes
Firstly, you should refrain from making sarcastic comments about Nobel prizes. It is not becoming of a professional attitude.
I made no sarcastic comment; I truly believe that if you can substantiate your claims, you deserve a Nobel prize. You may think that I am hostile to you, but I am merely pointing out the grave implications of your claims.
Secondly, you appear to have completely misunderstood the points I am making.
That may very well be, since you have used some quite confusing language.
Correct, but you are simply repeating my agreement with SR on this point. You do not appear to understand that the transverse Doppler shift reflects this time dilation.
Please show us the mathematics that shows this to be the case. As far as I can tell from my studies of SR, Doppler shift has nothing to do with time dilation.
I agree, but again I am not sure what point you are trying to make. I am simply saying that initially, the two clocks were synchronised on Earth, before one of them took off then flew far away and took a long run up to fly past overhead at speed. The moving clock is relatively slower than the Earthbound clock as it flies past. This is fully in accord with SR as you must agree. I am not proposing any change to the geometry of space-time outside of accepted theory.
I am asserting that because the moving clock is relatively slow, then the staionary clock is relatively fast and so one must observe blueshift when observing it from the moving frame.
In SR, there is no such thing as an absolutely stationary clock. Either clock may be taken to be moving and all clocks in motion relative to each other are time dilated in the frame of reference in which one of the clocks is stationary. The Hafele-Keating Experiment is not representative of SR time dilation as it is not simply comparing differences in reference frames. In the scenario of the experiment, one has the non-inertial frames of moving bodies in a rotation within the gravitational field of the Earth. This twice removes it from the realm of SR.
Special Relativity takes velocity as purely relative and therefore argues the reciprocity of redshift from this purely geometric analysis. It takes no account of the common reference frame in which the clocks were, or would become, synchronised. It therefore DOES ignore initial conditions.
It is definitely possible to begin with clocks that are synchronized and then move one clock and demonstrate, mathematically, that it becomes unsynchronized. This is a problem in some textbooks on the subject. So you are simply incorrect to say that SR ignores initial conditions in this manner.
We agree yet again that the moving clock is dilated, but you are resisting acknowledging that consequently, the stationary clock must be relatively faster.
It is faster in the reference frame of the currently identified as stationary clock. This is not the case in the reference frame in which the other clock is at rest.
This relative time rate differential is fully in accordance with SR but it does expose a contradiction in the theory. You (and the mainstream), are hanging on grimly to the purely geometric analysis of SR in your statement that time is dilated in both frames. It is not the case and time is only dilated in the moving frame as SR itself predicts. The stationary clock carries on ticking at the same old rate. and SR contradicts itself with the assertion of temporal reciprocity. This is the core of my dissagreement.
Well, you're going to have to demonstrate this.
Firstly, let's see exactly what the "facts" are. It IS a fact that time dilates in the moving frame and we see experimental evidence of this. However, no one has yet carried out an experiment to see what the observations are from the moving frame. It is not yet an established fact that redshift is observed from the moving frame, only from the stationary frame.
If you can come up with a theory without the reciprocal time dilation that is self-consistent, please feel free to do so and collect the accolades to which you are due.
Like all good "theories", or in this case, modifications to theories, a postulate must be capable of being disproved. So, I challenge the scientific community to disprove my assertions and carry out an experiment to measure the shift as observed from the moving frame. This should be possible with a fast fly-by of a known frequency light source past a light source of the same frequency in an inertially slower frame. I predict a blueshift of the light source as observed from the moving frame.
All experiments are done from "the moving frame", so the challenge has been taken up and completed, thousands if not millions of times.

10. Kenhughes, please explain how you can decide which of the two frames is at rest and which is moving. How can you distinguish between them?

11. I understand that there can never be any point of reference which can be called stationary when discussing relativity.

I don't understand what Ken means by Transverse doppler effect. If you are looking at right angles to the path of motion then, at the point when you are at a right angle, there is no relative motion. If there is no relative motion then there is no red or blue shift. Of course the moment of right angeledness only lasts for an instant unless both points of observation are moving in the same direction and at the same speed, that is on parallel courses. Then the transverse condition would apply longer but once again due to the courses being parallel there would be no relative velocity.

Time dilatation is a completly different question.

12. Dishmaster,

There is no preferred frame as we all know. I am not saying any frame is stationary. I simply use the terms "stationary" and "moving" as an easy description of "the frame that accelerated away from the one that didn't" and "the frame that never accelerated".

I distinguish between the frames by considering that only one of them accelerated and moved from an inital, common frame.

13. Sealeaf,

Look up Transverse Doppler shift in Wikipedia (that's easiest). It will confirm there IS such an effect. It will tell you it is due to the time dilation in the "moving" frame and it will tell you the degree of shift is given by the formula from SR;-

t = ROOT(1 - v,squared/c,squared). This is the well known formula for time dilation due to velocity v.

........at the point when you are at a right angle, there is no relative motion.
Oh yes there is. The moving entity is travlleing from "left" to "right". That's relative motion.

I agree there is only an "instant" when the moving entity passes by. Any experiment must therefore measure the shift from approach, through perigree and beyond. We can calculate what the simple Doppler shift should be at all instances and subtract these values from the results. We will be left with a constant blueshift, quantified by the above formula.

This is all I am saying, nothing more. The rest is understanding the implications of it. There is no more math since SR has all the correct math and I am not dissagreeing with any of it, only the interpretation of it. Only the experiment will prove or disprove the hypothesis.

14. PhysBang,

You reply is more complicated than the other two which I have just answered so please bare with me while I find time to do it justice.

15. Originally Posted by kenhughes
SpeedFreek,

I see you mock but provide no reasoning. That's good, very good. It means I've struck a nerve. It must be very frightening when someone shakes the very foundations of one's beliefs. Science is not based on beliefs though. It is based on sound theory and experimental evidence.
Not frightening, but laughable. I have seen this misconception many times before.

Originally Posted by kenhughes
You state the SR "symmetrical" mantra very well, but that is all it is, a mantra. It is not a proven fact. If you seek proof, (either way), then you will have to wait for the results of the experiment I suggest. Until then, my hypothesis stands. Afterwards, you may have to eat your words.
I haven't seen the suggested experiment. Where did you suggest it? I hope it only includes truly inertial frames of reference.

Originally Posted by kenhughes
The Hafele & Keating experiment is indeed comparing inertial frames. The time dilation of the moving clock is due to the fact that it moved. Pretty obvious really. (You cannot argue that because it went around in a circle then it was not inertial. How big a circle do you think we need to make it inertial?)
For starters, any clock on a jet-plane circumnavigating the Earth is in an accelerated frame, as the jet is constantly accelerating. An aeroplane flying along using its engines cannot be an inertial frame, by definition. So that's two out of three frames that are already non-inertial.

Any clock on the surface of the Earth is also in an accelerated frame. You are in a non-inertial frame as you sit in front of your computer, using the ground below you to resist the gravity of the Earth.

Inertial frames are either frames in empty space where there is no gravitational influence or accelerations involved, or a freely falling frame in a uniform gravitational field.

None of the frames in Hafele-Keating are inertial frames, therefore we should not expect any symmetry in the time-dilations.

There is, however, an inertial frame in which all the readings of all the clocks (which are all in accelerating frames) makes sense under SR. It is a frame at rest in relation to the centre of the Earth, where the Earth rotates around that frame. From that frame, the clock flying against the Earths rotation was moving slowest, the clock stationary on the ground (and thus rotating with the Earth) is moving faster and the clock flying with the Earths rotation moves faster still - and this corresponds to the time-dilations found in the experiment.

16. SpeedFreek,

Not frightening, but laughable. I have seen this misconception many times before.

Well, when you've finished laughing, perhaps you would care to point out where my reasoning fails. This should be easy for someone so familiar with the point. I am not saying SR is completely wrong. The theory stands OK but only the prediction of temporal reciprocity is wrong.

I haven't seen the suggested experiment. Where did you suggest it? I hope it only includes truly inertial frames of reference.

I will repeat;- I suggest two light sources of the same frequency. One stays on Earth, but if this offends you, let's say it escapes the Earth's gravity and proceeds at a slow relative velocity in a straight line in some direction. The other takes off and flies far away in order to take a long run up to gather as much speed as possible in the opposite direction to the other. They both fly by each other and observations are made from both frames as they pass. The faster one has the slower clock. The slower one has the faster clock. I predict observations of redshift looking from the slower one and blueshift looking from the faster one.
So, what's wrong with this. You can tell I'm stupid if you like, but please do not do so without explaining where I am wrong. I had the courtesy to answer your question as to how I differentiate between frames, so maybe you will will return the respect and give me, and indeed all of us, your clear reasoning. We're all waiting.

None of the frames in Hafele-Keating are inertial frames, therefore we should not expect any symmetry in the time-dilations.

Your understanding of the 1971 experiment is incorrect. There IS an inertial component due to the tangential velocities involved. This is also evident for the GPS where they calculate the faster clock rate due to the higher elevation in the gravitational field, but then SUBTRACT from this, the slower clock rate due to the linear component of the orbital speed of the satellite, (the inertial component). Practically, the inertial component is about 20-25% of the gravitational one so the there is a net increase in time rate for the satellite clocks. The clocks are adjusted slow by this amount, so that when in orbit, they run synchronised with the Earth clocks as observed from Earth.

Your last paragraph is completely correct and aligns with the above. You contradict yourself by your previous assertion that there is no inertial frame.

17. Hi PhysBang,

I made no sarcastic comment; I truly believe that if you can substantiate your claims, you deserve a Nobel prize. You may think that I am hostile to you, but I am merely pointing out the grave implications of your claims.
Accepted. I agree, my hypothesis, when proven correct, will shake some people's foundations. We will then have to understand how there is no reciprocity and also no preferred frame. Some will be scared of the implications of a "universal" frame against which everything else is relative. I am not. (It's not the Ether).

(Reply to be continued via edit) I have to go out now.

18. Originally Posted by kenhughes
SpeedFreek,

Not frightening, but laughable. I have seen this misconception many times before.

Well, when you've finished laughing, perhaps you would care to point out where my reasoning fails. This should be easy for someone so familiar with the point. I am not saying SR is completely wrong. The theory stands OK but only the prediction of temporal reciprocity is wrong.
I pointed it out in the rest of my post - you quoted it below.

Originally Posted by kenhughes
I haven't seen the suggested experiment. Where did you suggest it? I hope it only includes truly inertial frames of reference.

I will repeat;- I suggest two light sources of the same frequency. One stays on Earth, but if this offends you, let's say it escapes the Earth's gravity and proceeds at a slow relative velocity in a straight line in some direction. The other takes off and flies far away in order to take a long run up to gather as much speed as possible in the opposite direction to the other. They both fly by each other and observations are made from both frames as they pass. The faster one has the slower clock. The slower one has the faster clock. I predict observations of redshift looking from the slower one and blueshift looking from the faster one.
So, what's wrong with this. You can tell I'm stupid if you like, but please do not do so without explaining where I am wrong. I had the courtesy to answer your question as to how I differentiate between frames, so maybe you will will return the respect and give me, and indeed all of us, your clear reasoning. We're all waiting.
I won't tell you that you are stupid, as you are not stupid, just harbouring a few misconceptions.

So, the first light source escapes Earths gravity (and the Suns?) and proceeds at a slow "relative velocity" in some direction. I take it by "relative velocity" you mean velocity relative to the Earth. The light source must be in inertial motion for the experiment to be valid, so we must ignore the acceleration involved in getting it up to "relative velocity. If we are testing whether time-dilation is symmetrical between inertial frames of reference in relative motion, the experiment may only start after the light sources have accelerated and must end before they accelerate again.

Now, the other light source takes off (accelerates) and flies far away in order for it to be able to turn round (which requires acceleration) and build up a large velocity, relative to the Earth (which requires acceleration). Once it has accelerated to that large velocity, relative to the Earth, it must turn off its engines in order to be in inertial motion. Once this is the case, the experiment can begin.

So, one light source has a low speed, relative to the Earth, whilst the other has a high speed, relative to the Earth.

But each light source has the same speed, relative to the other light source. Whilst each frame will measure a different velocity relative to the Earth, they will measure the same speed relative to each each other.

If they synchronised their clocks at a distance after they both accelerated, then each frame will calculate the others clock to be running slower than their own, by the same amount, as they pass each other. Whilst they remain in relative inertial motion (no accelerations), there is no experiment that can be performed in either frame that will show otherwise.

They might send signals to each other in order to synchronise their clocks at a distance before they pass, and then send other signals after they pass to measure the elapsed time for the other frame. Each will get the same result for the other frame - less elapsed time than in their own frame, each by the same amount.

Whatever signals they send between each other (as they converge) will be blueshifted by the same amount for each frame. Whatever signals they send to each other after they have passed and are now diverging will be redshifted by the same amount for each frame.

It is worth noting here that Doppler effect does not reflect time-dilation which is purely a function of relative speed and is the same whether the objects are moving towards, away, or across each other.

This is what the symmetry of time-dilation means, and it is unfalsifiable in the absence of any accelerations, as you are only calculating the other frames clock rate, relative to your own, due to their speed relative to you. Any attempt to synchronise clocks in relative motion, either at a distance or when passing each other, will result in symmetrical results between the frames.

Of course, if you want to check the results, the only real way is to bring the clocks together and compare them. Unfortunately for us, that requires an acceleration, which would define who was non-inertial and thus show the predicted asymmetry for that situation between when they synchronised their clocks and when they arrive!

Originally Posted by kenhughes
None of the frames in Hafele-Keating are inertial frames, therefore we should not expect any symmetry in the time-dilations.

Your understanding of the 1971 experiment is incorrect. There IS an inertial component due to the tangential velocities involved.
I know there is an SR component in the calculation, of course, but we have to consider the accelerations, as well as the velocities. The constant acceleration of the airplane means it is constantly changing frames of reference. SR is used to calculate across all these frames, and provides a pretty accurate prediction for the "kinetic" component.

But the part in SR about time-dilation being symmetrical between inertial frames does not apply, as the frames in question are constantly changing. For the symmetry to apply the frames involved both have to remain completely inertial - i.e. they cannot change - they cannot accelerate. The symmetry is only between constant motion.

Now, according to SR, an object in inertial motion, relative to your own inertial frame, will be time-dilated by a certain amount, relative to your rest frame. It doesn't matter if it is moving at 0.866 c towards you (blueshifted) or at 0.866 c away from you (redshifted) or moving across your view at 0.866 c, it will be time-dilated by a certain amount, known as gamma, which in this case is 2, meaning time passes at twice the speed for you as it does for an object moving at 0.866 c relative to your rest frame.

Now, if you know the object is the one who accelerated, then you know that if they return they will show less elapsed time. And, of course. if the object knows it accelerated, it knows that it has to calculate the time-dilation from your frame, as you didn't accelerate, in order to calculate what the relative elapsed times will be when it returns to your frame.

But in the absence of any knowledge of accelerations, objects in relative motion can only calculate the other to be time-dilated in relation to themselves, due to their relative speed. And if they start the experiment and end the experiment whilst only in inertial motion, they each find the same result for the other if they synchronise their clocks whilst in different frames of reference.

Originally Posted by kenhughes
This is also evident for the GPS where they calculate the faster clock rate due to the higher elevation in the gravitational field, but then SUBTRACT from this, the slower clock rate due to the linear component of the orbital speed of the satellite, (the inertial component). Practically, the inertial component is about 20-25% of the gravitational one so the there is a net increase in time rate for the satellite clocks. The clocks are adjusted slow by this amount, so that when in orbit, they run synchronised with the Earth clocks as observed from Earth.
The GPS is a different case, as GPS satellites are in free-fall and therefore can be considered to be inertial frames of reference (or at least a good approximation), whereas a flying aircraft with engines on can never be an inertial frame, due to the fact it is constantly accelerating (which means constantly changing its frame of reference).

Originally Posted by kenhughes
Your last paragraph is completely correct and aligns with the above. You contradict yourself by your previous assertion that there is no inertial frame.
I did not contradict myself, you missed my meaning. The only inertial frame in these here parts is either an object in free-fall, or an object at rest in relation to the centre of the Earth. None of the clocks in the Hafele-Keating experiment were in free-fall, or at the centre of the Earth. But to an observer at rest in relation to the centre of the Earth, where the Earth rotates in relation to their frame, the Hafele-Keating experiment shows the results as predicted by SR from that inertial frame. An observer in an inertial frame can use SR to calculate the results in non-inertial frames, but they will not find symmetrical time-dilation for those frames (unless they are accelerating in exactly the same way, relative to the inertial frame).

For an inertial frame of reference at rest in relation to the centre of the Earth which rotates around it, the clock flying against the rotation was moving slowest, whilst the clock on the ground was moving faster, and the clock moving with the rotation was moving fastest. The results make sense, under SR, for that inertial frame.

Whereas, an observer at the U.S. Naval observatory might have been surprised to find that the clock that flew against the rotation gained time in relation to his clock, whereas the clock that flew with the rotation lost time, as he might have considered himself an inertial frame, and that both planes had the same motion, relative to him. As we know, he would have been incorrect to assume that.

19. Originally Posted by kenhughes
Hi PhysBang,

I made no sarcastic comment; I truly believe that if you can substantiate your claims, you deserve a Nobel prize. You may think that I am hostile to you, but I am merely pointing out the grave implications of your claims.
Accepted. I agree, my hypothesis, when proven correct, will shake some people's foundations. We will then have to understand how there is no reciprocity and also no preferred frame. Some will be scared of the implications of a "universal" frame against which everything else is relative. I am not. (It's not the Ether).

(Reply to be continued via edit) I have to go out now.
You are shaking no foundations and you have proven nothing.

First, you need to understand SR.

The spherical light wave (SLW) remains centered at the origin of any frame.

Now, let's look at the coordinate (0,y,0) in the unprimed frame. It views a straight line of motion from the origin of its frame. However, a primed observer co-located at (0,y,0) when the light hits views an angled line from its origin. So, the primed observer will view the red shift of doppler.

Now, lets look at the primed coordinate (0,y,0). A primed observer at that location will view a straight line for the light while a moving unprimed observer will view an angled line from its origin and again, the moving observer will view the doppler effect while the primed stationary observer will not.

This is the reciprocal doppler effect. So, your argument proves nothing.

I have seen this kind of thing before and it is connected to the failure to understand that in any frame, the SLW remains centered at the origin.

20. Chinglu,

Dishmaster
(Moderator)

21. Originally Posted by PhysBang
If you can come up with a better theory that fits the facts or if you can demonstrate that special relativity is incorrect, you are welcome to your Nobel prize.
If I believed (like kenhughes) that I could show SR to be incorrect I would think I had a good chance of receiving a Nobel Prize.
If I believed I could show SR to be incorrect I would send my "proof" to a reputable scientific journal, or get a first opinion from a top academic, rather than make such an announcement on a general science Internet Forum such as TSF.

22. Halliday,

You must know what a thankless task that would be for a non physicist. I wrote a book instead but I am still "testing" my ideas on forums such as these. As of this moment, I can find no reason to withdraw my assertions. If I do find a reason, I will announce my withdrawal with the reasoning behind it. This would help refute any such falses assertions in the future.

23. Originally Posted by kenhughes
Halliday,

You must know what a thankless task that would be for a non physicist. I wrote a book instead but I am still "testing" my ideas on forums such as these. As of this moment, I can find no reason to withdraw my assertions. If I do find a reason, I will announce my withdrawal with the reasoning behind it. This would help refute any such falses assertions in the future.
I was backing up the comment made by PhysBang about the Nobel Prize!
I do not accept it is possible for a "non physicist" to demonstrate SR is incorrect even if that were the case-and I don't believe it for a second!

24. SpeedFreek,

Thankyou for taking the time and trouble to truly engage in this philosophical debate despite your convinction that you are right and I am wrong. Presently, I am equally convinced I am right, so one of us will have to change thier mind. You have the weight of the sceintific community behind you and I am simply one person harbouring a few misconceptions, but that's OK. I am quite prepared to withdraw if I can see where my reasoning fails but at the moment, I still do not see this.

So, the first light source escapes Earths gravity (and the Suns?) and proceeds at a slow "relative velocity" in some direction. I take it by "relative velocity" you mean velocity relative to the Earth. The light source must be in inertial motion for the experiment to be valid, so we must ignore the acceleration involved in getting it up to "relative velocity. If we are testing whether time-dilation is symmetrical between inertial frames of reference in relative motion, the experiment may only start after the light sources have accelerated and must end before they accelerate again.
Well, we all know you simply cannot get away from at least some remnents of gravitation and so, according to your reasoning you might never be able to take up an inetrial frame. I take it therefore, that you agree we can consider an inertial frame independantly from the accelerating frame that it may exist within? Otherwise SR is useless to us.
By relative velocity, I was thinking "velocity relative to the Earth", at least for the time being.
It is the acceleration which achieves the final constant velocity in the inertial frame, so we cannot ignore the effects of it, but this is nit picking. Although, wait a minute..........

I begin to see more clearly now where our thinking diverges and I think this is the real sticking point. If you can understand what I say from here, you will either be able to destroy my reasoning or you will have to reconsider your understanding of SR.
Conventional relativists are only interested in relative motion at the point in time when observations are taking place, ie inertial frames. My bone of contention is that I don't believe you can ignore what happened BEFORE we got to the two inertial frames. You cannot delete history or the effects of it. This is why I start my reasoning (not your experiment) earlier, with both light sources being the same frequency when initially on Earth. The light sources are effectively clocks, demonstrating the time rate in the Earth's frame, albeit partly due to gravitational time dilation.
When the clocks reach a significant distance from Earth, they run faster and exhibit blueshift as observed from Earth, but both still run at the same rate as each other (for the time being) and we can perhaps ignore any residual gravitational effects. Let's say they always stay at a similar distance from the Sun to enable us to ignore small variations in the Sun's gravitational/time dilatational field. Even if you did not wish to ignore this, we could calculate and adjust the observations to account for the Sun's gravitational field.
So, we now have two light sources,(clocks) of the same frequency/time rate. Then one shoots off, does a u-turn and speeds back towards the other.

We now consider the exact moment when the faster, or more accelerated one passes the slower, less accelerated one.
SR states that time really DOES run slower in the more accelerated frame, (ie. the inertial frame that has experienced more acceleration), yet it claims both are observed as slow, to the same degree as the other, from either frame. This is inconsistant and cannot be true because of the real time rate differential between the two frames.
You have only considered the relative doppler shifts when comparing inertial frames and so predict reciprocal redshift of the light, but there is more to it than that.

There IS a "Transverse Doppler shift" due to the time dilation in the more accelerated frame which is not a simple Doppler effect. We must both agree this is the case or we cannot move on, so if you are unaware of this, please do look it up on Wikipedia. It IS there. If you don't respect Wikipedia, then it will also be there on more scientific papers. It's just that Wikipedia is quickest.
So, I agree that there will be a reciprocal redshift observation from either frame, purely due to Doppler effects, but I am also saying there will be an additional relative redshift of the light source within the more accelerated frame superimposed on this reciprocal redshift observation.
I think you are confusing Doppler effects with real time dilation and they are not the same thing.
The term "Transverse Doppler Shift" is confusing because it starts us thinking about Doppler shift due to motion. The transverse effect is not due to relative motion. It is due to the time dilation in the accelerated frame. It would be better labelled simply "Transverse shift" or "Time dilation shift", but that's just a suggestion.

The basis of my arguments is the REAL time dilation in the more accelerated frame and you cannot ignore this. It is a prediction from SR after all.

In support of this understanding, consider relative motion at the speed of light where time stands still. This is a real effect, demonstrated in ascending order by Hafele & Keating, the GPS, and the fact that any image gets anywhere at all in no time at all when v=c. (The four vector in the frame of the light has become infinite)

I have run out of ideas to explain it more fully, so I now invite you to comment again and point out where this is wrong.

25. Halliday,

Hear no evil.

26. Ken,

You have given us no reason to think that accelerating introduces any additional effect to redshift and no evidence to evaluate whether or not this idea matches our observations of the physical world.

You have a conviction; but your conviction that a hypothesis might be true is not enough to warrant that we take it as a serious challenge to existing theory that is supported by a wealth of evidence.

In order to even begin to contemplate your idea, we need to see what change acceleration introduces, in what way, and to what degree. That is, given a measure of acceleration, we need to see a specific measurable change in some other physical quantity.

Once this is done, you have to meet an additional burden. Since at least the work of Isaac Newton, we have used physical theories in which acceleration is relative (except for rotation) and you are saying that acceleration is not relative. You have to show that your theory in which some change is introduced through acceleration which is not relative. You have to show why existing theories with relative acceleration so accurately fit the available observations and measurements and how your theory does better than these theories with the available evidence.

This procedure of attempting to show a measurable difference generated by theory that succeeds better than existing theories is how Newton established his gravitational theory. It is how Einstein established his gravitational theory. It is how other scientists have attempted, and so far demonstrably failed, to improve upon either Newton's theory or Einstein's throughout history.

27. Ken, I do understand where you are coming from with this, as I was where you are, some years back.

Originally Posted by kenhughes
If we are testing whether time-dilation is symmetrical between inertial frames of reference in relative motion, the experiment may only start after the light sources have accelerated and must end before they accelerate again.
Well, we all know you simply cannot get away from at least some remnents of gravitation and so, according to your reasoning you might never be able to take up an inetrial frame. I take it therefore, that you agree we can consider an inertial frame independantly from the accelerating frame that it may exist within? Otherwise SR is useless to us.
By relative velocity, I was thinking "velocity relative to the Earth", at least for the time being.
I do agree. If we cannot take up a truly inertial frame due to not having access to a uniform gravitational field, what we have to do is make a calculation of the gravitational component and allow for it, which is what is done. This is how we calculate the SR component of time-dilation for a GPS satellite to be - 7 microseconds a day.

But what I am saying is, in these here parts, we cannot directly measure the symmetrical relationship between inertial frames, we can only calculate it, and if we think up an experiment using only the SR component and using no accelerations, those calculations will confirm that symmetry. Unfortunately, we need an empty universe around us if we are to test it directly.

As an extreme example, (and to counter your argument below) imagine an identical Earth like planet, coasting through the solar system. It will have a definite speed, relative to the Earth, and let's really make this interesting - lets say it has exactly the same speed as us, when compared to the CMBR "rest frame", but in the opposite direction! (This means it is moving at around ~1200 km/s relative to us) We send signals to each other, explaining how we calculate time based on the "vibrations" of a caesium atom, and tell each other how time is passing on our respective planets. After we calculate out all the differences in gravitational influence of the contents of the solar system on each planet, we both conclude the others time is running slower than our own, by the same amount.

Who is correct? Who accelerated? How can we possibly prove it either way?

Originally Posted by kenhughes
Conventional relativists are only interested in relative motion at the point in time when observations are taking place, ie inertial frames.
This is because any science performed, in any laboratory, should show that the laws of physics are the same in all frames of reference. Whatever your frame, you should be able to make a pair of observations and come to a conclusion that complies with the laws of physics, based on those observations.

Originally Posted by kenhughes
My bone of contention is that I don't believe you can ignore what happened BEFORE we got to the two inertial frames. You cannot delete history or the effects of it. This is why I start my reasoning (not your experiment) earlier, with both light sources being the same frequency when initially on Earth. The light sources are effectively clocks, demonstrating the time rate in the Earth's frame, albeit partly due to gravitational time dilation.
When the clocks reach a significant distance from Earth, they run faster and exhibit blueshift as observed from Earth, but both still run at the same rate as each other (for the time being) and we can perhaps ignore any residual gravitational effects. Let's say they always stay at a similar distance from the Sun to enable us to ignore small variations in the Sun's gravitational/time dilatational field. Even if you did not wish to ignore this, we could calculate and adjust the observations to account for the Sun's gravitational field.
So, we now have two light sources,(clocks) of the same frequency/time rate. Then one shoots off, does a u-turn and speeds back towards the other.

We now consider the exact moment when the faster, or more accelerated one passes the slower, less accelerated one.
SR states that time really DOES run slower in the more accelerated frame, (ie. the inertial frame that has experienced more acceleration), yet it claims both are observed as slow, to the same degree as the other, from either frame. This is inconsistant and cannot be true because of the real time rate differential between the two frames.
You have only considered the relative doppler shifts when comparing inertial frames and so predict reciprocal redshift of the light, but there is more to it than that.

There IS a "Transverse Doppler shift" due to the time dilation in the more accelerated frame which is not a simple Doppler effect. We must both agree this is the case or we cannot move on, so if you are unaware of this, please do look it up on Wikipedia. It IS there. If you don't respect Wikipedia, then it will also be there on more scientific papers. It's just that Wikipedia is quickest.
So, I agree that there will be a reciprocal redshift observation from either frame, purely due to Doppler effects, but I am also saying there will be an additional relative redshift of the light source within the more accelerated frame superimposed on this reciprocal redshift observation.
I think you are confusing Doppler effects with real time dilation and they are not the same thing.
The term "Transverse Doppler Shift" is confusing because it starts us thinking about Doppler shift due to motion. The transverse effect is not due to relative motion. It is due to the time dilation in the accelerated frame. It would be better labelled simply "Transverse shift" or "Time dilation shift", but that's just a suggestion.
Here is a quote from the wiki article (my bold):

"Sometimes the question arises as to how the transverse Doppler effect can lead to a redshift as seen by the "observer" whilst another observer moving with the emitter would also see a redshift of light sent (perhaps accidentally) from the receiver.
It is essential to understand that the concept "transverse" is not reciprocal. Each participant understands that when the light reaches her/him transversely as measured in terms of that person's rest frame, the other had emitted the light aftward as measured in the other person's rest frame. In addition, each participant measures the other's frequency as reduced ("time dilation"). These effects combined make the observations fully reciprocal, thus obeying the principle of relativity."

Did you miss that part? And check out the principle of relativity.

Originally Posted by kenhughes
The basis of my arguments is the REAL time dilation in the more accelerated frame and you cannot ignore this. It is a prediction from SR after all.
Of course, if you include the accelerations you get the correct answers at the end of the experiment. This is the solution to the "paradox" of the twins. There is no question of that and this is not debated.

But this does not falsify the symmetry of time-dilation where accelerations are not involved, or for an experiment performed between accelerations, as I have described already.

From our frame of reference here on Earth, if an identical planet was moving through the solar system they would be time-dilated in relation to us - their clocks would "run slower" than ours. And the same would be true, the other way round. Any experiment performed on either planet would show this.

28. PhysBang,

Thankyou again for taking the time to respond.

Firstly, if you read SpeedFreek's last response you will see that acceleration and the subsequent velocity induces time dilation as well as Doppler shift. SR predicts this.
I don't think I ever said acceleration is not relative. I don't even think I have implied it, I certainly didn't mean to. For the sake of clarity, acceleration IS relative.
Also, you cannot have a conviction that an idea MIGHT be true, you can only be convinced that it IS true. I am not CONVINCED either way, but at the moment I think that the established scientific community DOES have a CONVICTION about the reciprocity of time dilation. The community starts off with this premise as if it were proven fact and as far as I can tell it is NOT yet established. Wiki' states there has only been one experiment to date to prove transverse effects and that was only the redshift observed from the "stationary" frame. There has, as yet, been NO experiment to verify what shift is observed from the moving frame.

Finally, I have no dissagreement with Either Newton or Einstein, or indeed any observations made to date. I think perhaps the only way to resolve this is to carry out the experiment as suggested and measure the shift from the accelerated frame. This has not yet been done.

29. Originally Posted by kenhughes
There has, as yet, been NO experiment to verify what shift is observed from the moving frame.
And again I say: every frame is a moving frame. You are imagining that there are such things as moving frames or accelerated frames, that these frames have some sort of special status that other frames do not have. As such, you are imagining that there is some sort of non-relative acceleration or motion. You have provided no details of what the special effects of this acceleration might be. You have the vaguest of hypotheses and such things are no basis for serious doubt.

30. SpeedFreek,

Thankyou again for taking the time to respond.

But what I am saying is, in these here parts, we cannot directly measure the symmetrical relationship between inertial frames, we can only calculate it, and if we think up an experiment using only the SR component and using no accelerations, those calculations will confirm that symmetry. Unfortunately, we need an empty universe around us if we are to test it directly.
But we CAN carry out the suggested experiment, taking observations from both frames and adjusting for the calculated gravitational effects. This has never been done.

As an extreme example, (and to counter your argument below) imagine an identical Earth like planet, coasting through the solar system. It will have a definite speed, relative to the Earth, and let's really make this interesting - lets say it has exactly the same speed as us, when compared to the CMBR "rest frame", but in the opposite direction! (This means it is moving at around ~1200 km/s relative to us) We send signals to each other, explaining how we calculate time based on the "vibrations" of a caesium atom, and tell each other how time is passing on our respective planets. After we calculate out all the differences in gravitational influence of the contents of the solar system on each planet, we both conclude the others time is running slower than our own, by the same amount.

Who is correct? Who accelerated? How can we possibly prove it either way?
Yes, my mind has wandered in this direction a few times, creating an entity which comes from a completely unknown frame. You immediately identify the CMB as some sort of universal frame and this may be true. Certainly, I came to the conclusion there would have to be a reference frame that both planets could be referred to. However, since we do not know what the time rate for the new planet was before is attained its passing speed, we cannot know its relative time rate without observing the transverse shift. This is why I first referred to the Earth's frame as the initial frame for the two test rockets. That way, we knew their clocks were the same initially.
Also, the new planet's cesium atom would vibrate exactly the same to a local observer and he would describe it to us the same as we see it in an Earth lab'. But, the time rate on the new planet could be anything.
Again, you say both clocks run slow to the other observer, but this is a statement of belief rather than from proven fact, albeit a belief shared by the whole scientific community. You may be right but it is not proven and I can suggest some reasoning why this may be incorrect.

...................................In addition, each participant measures the other's frequency as reduced ("time dilation").
It seems we must both have been referring to this article this afternoon.

The above highlight is still just a statement as if it were fact, but there is no explanation as to why this might be the case. Nowhere can I find any explanation that demonstrates this reciprocity. It is always stated as fact without justification. It is a conviction. You could equally well state the reverse and argue non reciprocity and there would be no less justification.
As far as I can see we're stuck with a choice of beliefs until we do the experiment.

But this does not falsify the symmetry of time-dilation where accelerations are not involved, or for an experiment performed between accelerations, as I have described already.

From our frame of reference here on Earth, if an identical planet was moving through the solar system they would be time-dilated in relation to us - their clocks would "run slower" than ours. And the same would be true, the other way round. Any experiment performed on either planet would show this.
These are further statements of beliefs but without justification. I mean, you make the statements but give no reasons. This is always the case whenever and wherever I present these arguments. Frankly, I would be very happy to be proved wrong, just get closure.

31. PhysBang,

And again I say: every frame is a moving frame. You are imagining that there are such things as moving frames or accelerated frames, that these frames have some sort of special status that other frames do not have. As such, you are imagining that there is some sort of non-relative acceleration or motion. You have provided no details of what the special effects of this acceleration might be. You have the vaguest of hypotheses and such things are no basis for serious doubt.

I know all frames are moving. They're also accelerated, at least they've all BEEN accelerated. They have to be, otherwise they wouldn't be moving. All frames are special. Reality exists only within each frame, or as we say, the rules of science are the same within each of them. There is no reality BETWEEN frames since all observations are distorted across frames.

I don't know about "special status". The only attribute that sets each frame apart and defines each frame is the time rate. If two frames have the same time rate then they're the same frame.

All motion is relative as is all acceleration.

I don't know what else to say. I appear to be falsely accused.

32. Originally Posted by kenhughes
But we CAN carry out the suggested experiment, taking observations from both frames and adjusting for the calculated gravitational effects. This has never been done.
This is done every day with GPS satellites. After one cancels out the gravitational effects, one measures a time difference due to differences that can be accounted for purely by special relativity.
Originally Posted by kenhughes
I know all frames are moving. They're also accelerated, at least they've all BEEN accelerated. They have to be, otherwise they wouldn't be moving. All frames are special. Reality exists only within each frame, or as we say, the rules of science are the same within each of them. There is no reality BETWEEN frames since all observations are distorted across frames. I don't know about "special status". The only attribute that sets each frame apart and defines each frame is the time rate. If two frames have the same time rate then they're the same frame. All motion is relative as is all acceleration. I don't know what else to say. I appear to be falsely accused.
You are the person saying that we must take into account some sort of special effect from acceleration. You have not said what this is or to what degree is takes place. Could you in any way clarify?

33. Originally Posted by Dishmaster
Chinglu,

Dishmaster
(Moderator)
Many apologies. Can you teach me where I am wrong?

Many thanks.

34. Originally Posted by PhysBang
Originally Posted by kenhughes
But we CAN carry out the suggested experiment, taking observations from both frames and adjusting for the calculated gravitational effects. This has never been done.
This is done every day with GPS satellites. After one cancels out the gravitational effects, one measures a time difference due to differences that can be accounted for purely by special relativity.
And it is also worth noting here that, apart from GPS units on Earth receiving signals from GPS satellites, we also send signals from ground stations to those GPS satellites...

35. Originally Posted by kenhughes
These are further statements of beliefs but without justification. I mean, you make the statements but give no reasons. This is always the case whenever and wherever I present these arguments. Frankly, I would be very happy to be proved wrong, just get closure.
The logic of these statements simply falls out of the postulate that the speed of light is constant for all inertial frames, regardless of their motions. That is the reason, or the justification, for the symmetry.

36. PhysBang,

This is done every day with GPS satellites. After one cancels out the gravitational effects, one measures a time difference due to differences that can be accounted for purely by special relativity.
We are now all preaching the same thing to each other.

You are the person saying that we must take into account some sort of special effect from acceleration. You have not said what this is or to what degree is takes place. Could you in any way clarify?
No I am not. I am not proposing any special effect whatsoever. I am simply referring to the time dilation of motion as predicted by SR.

37. SpeedFreek,

And it is also worth noting here that, apart from GPS units on Earth receiving signals from GPS satellites, we also send signals from ground stations to those GPS satellites...
Correct. The frame of the satellites is bueshifted due to its faster clock. This is what blueshift means outside of classical Doppler effects. So we observe the slight time shift of the faster clock. More generally, we observe blueshift when looking into a frame with a faster clock. Similarly, we observe redshift when looking into a region with a slower clock.

So why do we think this obervation would be any different for inertial time dilation, just because the cause of it is different from gravitational time dilation? We are still looking into a region with a faster clock when making observations from the "moving" frame. Oh, but you are still hanging on to the recoprocal redshift so you won't see the point. Or will you? The point is, the frame which accelerated and moved really DOES have the slower clock. If we look into it, we see redshift. If we look out from it we see blueshift. Just as for a gravitational field. The fundamentals are the same. It is the time dilation that is the reality. Geometry, sometimes is just lnes on a piece of paper.

The logic of these statements simply falls out of the postulate that the speed of light is constant for all inertial frames, regardless of their motions. That is the reason, or the justification, for the symmetry.
Yes. The constancy of "c" does result in reciprocity, but from a purely geometric analysis only. We look at the geometry of two passing bodies and it is intuitive to regard them both as non preferred. Why should either one be different? This idea is then presented as justification for reciprocity. This makes perfect sense, but only geometrically.

This purely geometric view ignores the very time dilation which SR itself predicts. If both entities shared the same initial frame with the same time rate and only one of them moved, then the clock does run slower for the one that moved. (Hafele&amp; Keating again). If you are the one that moved, your clock is slower than the frame you left behind. If you look back to that frame, with its relatively faster clock, you must see blueshift.

I chose to take this view transversely to eliminate the classical Doppler effects and to observe purely the SR time dilation, the faster clock, the blueshift.

38. Originally Posted by kenhughes
SpeedFreek,

And it is also worth noting here that, apart from GPS units on Earth receiving signals from GPS satellites, we also send signals from ground stations to those GPS satellites...
Correct. The frame of the satellites is bueshifted due to its faster clock. This is what blueshift means outside of classical Doppler effects. So we observe the slight time shift of the faster clock. More generally, we observe blueshift when looking into a frame with a faster clock. Similarly, we observe redshift when looking into a region with a slower clock.
Well, in reality, we do NOT observe the slight time-shift of the faster clock on the GPS satellite. Remember, we adjusted the clock on the GPS to account for that shift, before take-off. We observe the moving GPS satellite clock to be running at the same rate as a clock that stationary on the surface of the Earth.
Now then, in practice, the GPS system actually requires us to assume the GPS satellite is the rest frame!

Why?

Because it is when a clock moves across the surface of the Earth, relative to that GPS rest frame, that the clock in your GPS unit in your car loses synchronisation with the GPS satellite, due to the time-dilation caused purely by the cars motion across the surface of the Earth.

The gravitational potential has been cancelled from the frame of the GPS unit in the car, so all that is left is the kinetic component, the SR component.
Originally Posted by kenhughes
So why do we think this obervation would be any different for inertial time dilation, just because the cause of it is different from gravitational time dilation? We are still looking into a region with a faster clock when making observations from the "moving" frame. Oh, but you are still hanging on to the recoprocal redshift so you won't see the point. Or will you? The point is, the frame which accelerated and moved really DOES have the slower clock. If we look into it, we see redshift. If we look out from it we see blueshift. Just as for a gravitational field. The fundamentals are the same. It is the time dilation that is the reality. Geometry, sometimes is just lnes on a piece of paper.
In this scenario, the frame that moved is your car, across the surface of the Earth, and your GPS unit proves this by measuring time-dilation relative to the GPS satellite. That's how your GPS unit calculates your movement across the surface of the Earth, relative to the rest frame of the GPS satellite.

So, you should see that gravitational time-dilation is absolute, as it is due to a difference in gravitational potential, whereas kinematic time-dilation is relative, as it is due to relative motion. We accounted for both the gravitational time-dilation and the SR time-dilation in the GPS satellite, relative to the surface of the Earth, so all that is left is the SR motion of the GPS unit on the surface of the Earth, relative to the rest frame of the GPS satellite.

Or, are you saying that an observer on a GPS satellite would not measure time in your car to be "running slower", relative to the satellite's clock, due to your motion across the surface of the Earth? (after calculating out the difference in gravitational potential, where time on the surface of the Earth already "runs slower")

The reason we adjusted the clock on the satellite before take off, is to be able to use it as a rest frame relative to the surface of the Earth, once the satellite was in orbit!

Originally Posted by kenhughes
The logic of these statements simply falls out of the postulate that the speed of light is constant for all inertial frames, regardless of their motions. That is the reason, or the justification, for the symmetry.
Yes. The constancy of "c" does result in reciprocity, but from a purely geometric analysis only. We look at the geometry of two passing bodies and it is intuitive to regard them both as non preferred. Why should either one be different? This idea is then presented as justification for reciprocity. This makes perfect sense, but only geometrically.

This purely geometric view ignores the very time dilation which SR itself predicts. If both entities shared the same initial frame with the same time rate and only one of them moved, then the clock does run slower for the one that moved. (Hafele&amp; Keating again). If you are the one that moved, your clock is slower than the frame you left behind. If you look back to that frame, with its relatively faster clock, you must see blueshift.
I really don't understand why you keep saying this. We know in Hafele-Keating that there are no inertial frames involved, so there will be no reciprocity.

39. SpeedFreek,

Well, in reality, we do NOT observe the slight time-shift of the faster clock on the GPS satellite. Remember, we adjusted the clock on the GPS to account for that shift, before take-off. We observe the moving GPS satellite clock to be running at the same rate as a clock that stationary on the surface of the Earth.
Wrong! We actually DO observe this. As you say, the clock was set SLOW on Earth, but in orbit it runs FASTER. We DO therefore see the blueshift of the clock from its Earth setting.

So, you should see that gravitational time-dilation is absolute,
Absolute time dilation?!!!!!! Completely wrong. All time dilation is relative. Nothing is absolute. When you look towards a planet, a star, a galactic core, a black hole, you see redshift. When you look outwards from the Earth or the Solar system, you see blueshift. This is traditional accepted relativity. Surely you are not dissagreeing with this?

I really don't understand why you keep saying this. We know in Hafele-Keating that there are no inertial frames involved, so there will be no reciprocity.
I thought we dealt with this earlier. There is an inertial component whether or not the frame is accelerated.

We are never going to get to an agreement on this and there is now little point in debating further. You are entrenched in conventional thinking and will not budge. I am now more convinced than ever that my ideas are correct and will ultimately prevail. It will be a shame though if it takes a hundred years. Not for me, but for science.

Have you never considered the possibility that what you've been taught was not completely correct? When I read engineering I always needed to understand the principles before I could accept them. Of course, this made life more difficult for me than for others who may have simply accepted what they were told to believe. That was easier I suppose. My approach paid divends though, as I had/have a more thorough grasp of things.

40. Originally Posted by kenhughes
SpeedFreek,

Well, in reality, we do NOT observe the slight time-shift of the faster clock on the GPS satellite. Remember, we adjusted the clock on the GPS to account for that shift, before take-off. We observe the moving GPS satellite clock to be running at the same rate as a clock that stationary on the surface of the Earth.
Wrong! We actually DO observe this. As you say, the clock was set SLOW on Earth, but in orbit it runs FASTER. We DO therefore see the blueshift of the clock from its Earth setting.
Not WRONG!, but perhaps I wasn't making myself clear. We do not simply see a blueshift from the clock in orbit.

The clock was set slow on Earth, to run faster in orbit, so we receive signals that are synchronised with a clock on the ground.

A GPS satellite orbits the Earth twice a day. Now, as the GPS satellite comes up over the horizon, towards the zenith (i.e. it is moving towards us), and after calculating out the gravitational component, we find the signals from it blueshifted, but as it moves from the zenith and sets beyond the other horizon, we find a redshift (as it is moving away from us).

But as we already know, Doppler shift is not indicative of time-dilation, it is an apparent ("time of light") effect. Once we calculate out the Doppler, we find the GPS satellite clock remains in synchronisation with a clock stationary on the ground.

Originally Posted by kenhughes
So, you should see that gravitational time-dilation is absolute,
Absolute time dilation?!!!!!! Completely wrong. All time dilation is relative. Nothing is absolute. When you look towards a planet, a star, a galactic core, a black hole, you see redshift. When you look outwards from the Earth or the Solar system, you see blueshift. This is traditional accepted relativity. Surely you are not dissagreeing with this?
Again, you misunderstand, and it is probably my fault. By absolute, I meant not reciprocal. The higher the gravitational potential, the faster the clock. The lower the gravitational potential, the slower the clock.

A clock around a neutron star will run slower than a clock around the Earth, as measured from Earth. A clock around Earth will run faster than a clock around a neutron star, as measured from the neutron star. There is no ambiguity between these measurements - they are "absolute" between the frames in question. Neither frame can assume the relationship between the two is any different.

But the same is not true for the time-dilation caused by relative inertial motion. The answer is not "absolute" between the frames in question. Each frame can consider themselves to be at rest and that the other is moving, whilst they are in inertial motion.

That is what I meant.

Originally Posted by kenhughes
I really don't understand why you keep saying this. We know in Hafele-Keating that there are no inertial frames involved, so there will be no reciprocity.
I thought we dealt with this earlier. There is an inertial component whether or not the frame is accelerated.
Yes, and we can calculate that "inertial" component. -7 microseconds a day. Clocks on a GPS satellite (if they weren't pre-adjusted) would run -7 microseconds a day (after calculating out the gravitational component), when measured from a stationary point on the Earths surface, due to their relative motion.

Now then, how do you think the GPS satellite processes instructions sent to it from ground stations on Earth? How are they synchronised?

Originally Posted by kenhughes
We are never going to get to an agreement on this and there is now little point in debating further. You are entrenched in conventional thinking and will not budge. I am now more convinced than ever that my ideas are correct and will ultimately prevail. It will be a shame though if it takes a hundred years. Not for me, but for science.

Have you never considered the possibility that what you've been taught was not completely correct? When I read engineering I always needed to understand the principles before I could accept them. Of course, this made life more difficult for me than for others who may have simply accepted what they were told to believe. That was easier I suppose. My approach paid divends though, as I had/have a more thorough grasp of things.
Oh, I understand the principles, which is why I accept them. It seems it is you that does not understand the principles, hence your reluctance to accept the postulated symmetry of time-dilation between inertial frames of reference.

The symmetry falls out of the postulate that the speed of light is constant between all inertial frames, regardless of their motions. That symmetry is unfalsifyable, which is why it is accepted (as long as all the rest of the theory checks out!). The only way you might try to disprove it is to come up with an experiment that includes only inertial motions, but with start and end points in the same frame, which is impossible, as there will always be a gravitational/acceleration component to deal with.

Serious physicists see the symmetry as an interesting curiosity of the theory that is completely consistent, but it is also unfalsifyable.

41. Originally Posted by kenhughes
No I am not. I am not proposing any special effect whatsoever. I am simply referring to the time dilation of motion as predicted by SR.
Now I begin to wonder if you have multiple personalities or if two or more people are posting with your account.

Earlier you wrote, "Special Relativity is WRONG, or at least the accepted interpretation of it is wrong in predicting reciprocity of observations between inertial frames. "

Later you wrote. "This difference in time rates takes account of the two frames first having synchronized clocks running at the same rate BEFORE the moving frame accelerated from rest. Special Relativity does NOT take this into account when it uses only geometry to predict reciprocity of observations. It ignores the initial conditions. As such it is naďve and incomplete."

More of your comments have introduced the non-SR idea that acceleration introduces some sort of special time dilation. Presumably this is what motivates your comment that, "Special Relativity is WRONG."

It's gross inconsistencies like this, along with a poor knowledge of physics expressed with undue conviction, that generates hostility from those who defend relativity theory, not the mere presence of a challenge. In general, what tends to make the difference between the physics crack pot and the person who merely makes a mistake is that the crack pot imbues their misunderstanding with a zealous conviction and ignores any reasoning contrary to their particular misunderstanding. Perhaps this is a sign of mental illness and it is doubly sad that such people, through their belligerence, produce such a natural antagonistic reaction.

As it stands now, please, "put up or shut up." Tell us what special thing acceleration does that special relativity should take into account or refrain from making these wild claims.

42. And there I think we shall leave it.

43. PhysBang/SpeedFreek,

I forgot to thank you both for your lively debate. Thankyou.

Whereas I have come to my conclusions through the processes of envisaging and philosophical reasoning, Buenker uses a more scientific language which may be more acceptable to you.

I would be very inyerested in your response to this paper as it proposes exactly the same as I.

44. Firstly, I should get the obvious out of the way. Having looked at the CV of the author, I see that he has a BS in math and a PhD in chemisty, and seems to be respected in his field, with a long list of accomplishments and many published and peer-reviewed papers. So why, I found myself wondering, is he publishing this paper in Apeiron, of all places? I won't hold it against him, though.

I am reading the paper, and I see better where you are coming from. I am used to using Einstein's derivation, whereas the author is using the derivation of Wolfgang Rindler (or is he misusing it? I think he is!).

It is too late at night for me to go into all of it right now, but here's an immediate problem I have with his analysis of the Hafele-Keating experiment:

It is sometimes argued that the above result does not follow directly from eqs. (2-6) because of the fact that the airplanes are not perfectly inertial systems (IS). The HK analysis claims, for example, that the non-rotating polar axis qualifies as an IS, whereas a point on the Earth’s surface away from the Poles does not. The centrifugal acceleration (RΩ^2) at the Equator due to the Earth’s rotation is 0.04 m/s^2 and it decreases with latitude χ in direct proportion to cos^2 χ.

Accordingly, the corresponding value at each of the Poles is null to be sure, but this argument nonetheless overlooks a critical point. There is also acceleration caused by the Earth’s orbit around the Sun. It has a magnitude of 0.006 m/s^2 and is the same at the Poles as it is at the Equator. It is therefore incorrect to claim that the non-rotating polar axes correspond to an IS and this fact raises a number of questions about the HK interpretation. In other words, where do we draw the line as to what level of acceleration is allowed for the purposes of choosing a reference frame from which to apply Einstein’s formula?
The above is a complete misrepresentation of the situation, as far as I can tell, and seems to be the authors distorted interpretation.

Firstly, he does not address at all the reason why the airplanes are not perfectly inertial systems, he only mentions a point on the Earth's surface away from the poles, and goes on to talk of the centrifugal acceleration of a point on the surface of the Earth, due to its rotation. He then agrees that there is no acceleration at the poles, but claims there is an acceleration caused by the Earth's orbit around the Sun, and so claims it is incorrect to say the non-rotating polar axes (notice the plural, he is talking about a point on the surface of the Earth, at the poles!) are inertial systems!

Well, in that case, neither was the clock at the U.S. Naval Observatory, as I have already said. So we should not see symmetry for that clock, as time-dilation is only symmetrical between inertial frames of reference in relative motion. But centrifugal acceleration due to the Earth's rotation is not the main reason that a point on the surface of the Earth is not an inertial system... that is due to the Earth's gravity making it an accelerating frame, as I will explain.

Now then, the claim is not, as far as I have ever been aware, that a point at the pole is an inertial system! The claim is that a point at rest in relation to the centre of the Earth, where the Earth rotates around it, is the inertial frame from which we can use SR to predict the results of the HK experiment. The reason for this is... due to the Earth's gravity. Sure, you can calculate for the other frames from any point on that axis, as long as you ignore gravity (i.e. don't make any measurements there, just use it as an origin point for your coordinate system), but I think the author is confused about what an inertial system means. It means no acceleration, no resisting gravity.

Whilst gravitational time-dilation would be greatest at the centre of the Earth, it is actually the closest to an inertial frame in the vicinity, as the "force" of gravity cancels out there. You are at the bottom of the well and are subject to no acceleration at all. There is no further to free fall. It is where you would end up if free-falling, subject to Earth's gravity, with nothing in the way!

Anywhere else in the gravitational field of the Earth, where you resist that field, by either accelerating yourself, or using some structure to stop yourself free-falling (like, say, the surface of the Earth), cannot be an inertial frame of reference, by definition. Which means any point on the surface of the Earth.

He seems to completely miss out that part, for some reason, and concentrates only on the rotation of the Earth.

And mentions nothing (unless he leaves it till a lot later!) of the constant acceleration of the airplanes either. Why refer to the planes and then not say anything about them? In fact, the more I read on, looking for a reference to their constant acceleration, the more unhinged it seems to get.

It also needs to be pointed out that a counter-balancing force can always be applied in any given rest frame that makes it an IS according to the accepted definition of perfectly null acceleration (validity of Newton’s First Law). The HK hypothesis would have us believe that an observer’s measurement of relative clock rates depends critically on whether such a potentially miniscule force has been applied to his detector or not. The IS argument that is used to explain why the slowing of clock rates is only predicted correctly when speeds are taken relative to the non-rotating polar axis is therefore specious.
This is utter nonsense, as far as I can tell - the HK "hypothesis" would have us believe nothing of the sort! It would have us believe that there are no inertial frames of reference used in the experiment, therefore there is no symmetry in the time-dilations. None of the frames in involved will find a symmetry, as they are all accelerating. But if you use an inertial frame as the origin point for the coordinate system that they all move around, SR predicts the time-dilations correctly based on their relative motions. That is what HK would have us believe.

That's enough to be going on with for now.

45. Hi SpeedFreek,

Thanks again for the response.

Firstly, I can suggest why he might have published it in Apeiron. As you say, he is not formally educated specifically in physics and so he may not have felt it appropriate to present himself as an expert on this subject within the physics community although he undoubtedly wanted to get his ideas out there somehow.

I understand and agree with all the points you make, except perhaps for your understanding of what the author is getting at. I don't think he is makimg the point that the Sun's gravitational field will necessarily affect the results of the experiment. I think he is simply trying to make the point that you can NEVER get a purely inertial frame' and so asks where should we draw the line in deciding where we CAN carry out viable experiments.

In other words, where do we draw the line as to what level of acceleration is allowed for the purposes of choosing a reference frame from which to apply Einstein’s formula?
I think we will all agree that the effects of the Sun's time dilation field at Earth orbit are practically constant at any point on or near the Earth. It is more or less a flat plane sloping towards the Sun at this distance with a slight orbital curvature. (Like a point near the rim of an inverted cymbal, only the spherical version). The effects are negligable, ie the change in time rate across the diameter of the Earth and due to the Sun's gravity is negligable and so we can ignore it.

Well, in that case, neither was the clock at the U.S. Naval Observatory, as I have already said. So we should not see symmetry for that clock, as time-dilation is only symmetrical between inertial frames of reference in relative motion. But centrifugal acceleration due to the Earth's rotation is not the main reason that a point on the surface of the Earth is not an inertial system... that is due to the Earth's gravity making it an accelerating frame, as I will explain.
You're saying it again as if it were fact. Remember Aristotle once said "It is the mark of an educated mind to be able to entertain an idea without accepting it". All I am asking is that you entertain the notions put forward, at least for the moment. If you were truly entertaining the ideas, you would not make contrary statements when the statement is a simple contradiction of the proposed idea. It's like a Punch and Judy show; "Oh yes it is", "Oh no it's not", and so we go on. In other words, you're not giving this a fair chance.

I, for one am convinced that a man of Buenker's stature is fully aware of what constitues an IS. I am, so I am sure he is.

Whilst gravitational time-dilation would be greatest at the centre of the Earth,..................
I'm not sure this is correct, but we won't go into that for now.

I accept what you say about gravitation being the major cause of a frame' being a non IS and in addition to any geometric acceleration. I think Buenker simply takes this as a given and focusses on relative motion.

The whole point surely, is that any non inertial effects can be calculated and the results adjusted for them. We are then left with purely inertial effects.

If you read on in the paper, and it IS worth reading it thoroughly, his proposed experiment to prove the non reciprocity, or Anti Symmetry as he calls it, must be worth doing, if only to silence dissenters such as we.

46. Originally Posted by kenhughes
I don't think he is makimg the point that the Sun's gravitational field will necessarily affect the results of the experiment. I think he is simply trying to make the point that you can NEVER get a purely inertial frame' and so asks where should we draw the line in deciding where we CAN carry out viable experiments.
The answer is that he is correct here - you can never get a purely inertial frame, except in an empty universe - which is the typical setting for Special Relativity (Minkowski space). You might find an approximately inertial frame, although under GR inertial frames take on a different meaning - a freely falling frame in a uniform gravitational field, for instance.

Originally Posted by kenhughes
In other words, where do we draw the line as to what level of acceleration is allowed for the purposes of choosing a reference frame from which to apply Einstein’s formula?
I think we will all agree that the effects of the Sun's time dilation field at Earth orbit are practically constant at any point on or near the Earth. It is more or less a flat plane sloping towards the Sun at this distance with a slight orbital curvature. (Like a point near the rim of an inverted cymbal, only the spherical version). The effects are negligable, ie the change in time rate across the diameter of the Earth and due to the Sun's gravity is negligable and so we can ignore it.
That may or may not be true, but what we cannot ignore is the gravity of the Earth itself. Nor can we subtract that component to find an inertial frame. You cannot just subtract out the gravitational/acceleration components and claim that you are then considering an inertial frame. This is an incorrect assumption.

Originally Posted by kenhughes
Well, in that case, neither was the clock at the U.S. Naval Observatory, as I have already said. So we should not see symmetry for that clock, as time-dilation is only symmetrical between inertial frames of reference in relative motion. But centrifugal acceleration due to the Earth's rotation is not the main reason that a point on the surface of the Earth is not an inertial system... that is due to the Earth's gravity making it an accelerating frame, as I will explain.
You're saying it again as if it were fact. Remember Aristotle once said "It is the mark of an educated mind to be able to entertain an idea without accepting it". All I am asking is that you entertain the notions put forward, at least for the moment. If you were truly entertaining the ideas, you would not make contrary statements when the statement is a simple contradiction of the proposed idea. It's like a Punch and Judy show; "Oh yes it is", "Oh no it's not", and so we go on. In other words, you're not giving this a fair chance.

I, for one am convinced that a man of Buenker's stature is fully aware of what constitues an IS. I am, so I am sure he is.
No, what I am saying is that nobody who understands SR expects the U.S. Naval Observatory to be an inertial frame. Nor do we expect the airplanes to be an inertial frame. Therefore we do not expect to see a symmetrical time-dilation. The prediction of symmetry was for inertial frames in relative motion, so trying to find that symmetry in non-inertial frames is an exercise in futility.

You cannot mathematically cancel out their non-inertialness, as their own frame defines the proper time on their own clock.

We cannot just calculate out any gravity/acceleration and expect to find the same results as if we were dealing with frames where no gravity/acceleration is involved. It just doesn't work that way.

What we can do is, as in the HK experiment, use SR to predict the kinematic component (which is accelerated) and use GR to predict the gravitational component, then combine them and see if it is close to the observed result.

Let's assume, for argument, that a clock would show less elapsed time if it were in an accelerating frame than if it were in the same place, but in an inertial frame. All you can do by calculating out the acceleration is predict what the clock would have read, were it inertial. You cannot expect it to actually have acted like an inertial clock, because it wasn't!

Originally Posted by kenhughes
Whilst gravitational time-dilation would be greatest at the centre of the Earth,..................
I'm not sure this is correct, but we won't go into that for now.
I will, and it is! (Except near the Sun, or the more massive planets). In the Earth-Moon system, gravitational time-dilation would be at its greatest at the centre of the Earth, relative to anywhere else. This is a prediction of General Relativity, due to the difference in gravitational potential. Time "runs slowest" at the centre of the Earth, when compared to the surface, or in orbit, or any further distant, until you start getting closer to the Sun, or Jupiter for instance. You must know of Pound-Rebka?

Originally Posted by kenhughes
I accept what you say about gravitation being the major cause of a frame' being a non IS and in addition to any geometric acceleration. I think Buenker simply takes this as a given and focusses on relative motion.

The whole point surely, is that any non inertial effects can be calculated and the results adjusted for them. We are then left with purely inertial effects.
No, I do not agree, as you have probably noticed already.

47. Originally Posted by kenhughes
I can suggest why he might have published it in Apeiron. As you say, he is not formally educated specifically in physics and so he may not have felt it appropriate to present himself as an expert on this subject within the physics community although he undoubtedly wanted to get his ideas out there somehow.
It was not my intention to question his physics credentials themselves. I was asking why a seemingly respected scientist is publishing in a fringe journal?

He has actually published quite a few papers within the physics community.
arXiv.org Search

But not this one.

Perhaps it failed peer-review? Or perhaps it wasn't submitted?

48. Sorry for the repeat posts, but I think something here needs clarification, as I sometimes tend to allow myself to get diverted from the bigger picture.

I am not contesting that transverse redshift would equate to gamma, if you can calculate out gravitational effects. I am contesting that, in the HK experiment, gamma for any of the frames involved (atomic clocks on aeroplanes and at the U.S naval observatory), would be predicted by SR to be symmetrical between the frames involved.

I am making a distinction between subtracting the gravitational/acceleration component to find the time-dilation of the kinematic component, and claiming you are always looking at an inertial frame where symmetrical time-dilation should apply, after having done so.

The whole thing seems misconceived, based on the very same misconception that led to the "paradox" of the twins.

The paradox: If time dilation is symmetrical between inertial frames of reference in relative motion, then how would the twin who went on a relativistic journey definitely end up younger than the other twin who stayed at home?

And we all know the answer to that one, don't we?

Ultimately, General Relativity was the answer.

GR still simplifies to SR "locally", i.e. when measuring circumstances where a difference in gravitational potential (which is what is also caused by acceleration) is of little issue, but GR removes the specialness of inertial frames by redefining them in terms of gravity, and in doing so removes the expectation of a symmetry in time-dilations, except in very particular circumstances, one of which is between freely-falling frames in relative motion, in a uniform gravitational field (however weak that field is). But the field has to be uniform - i.e. not a gradient. And it only works during free-fall - no accelerations allowed! (GR also redefined acceleration, somewhat, hence you are accelerating right now). A cop out? Or a deep philosophical insight?

So, what we end up with is a situation where no symmetry is expected in the HK experiment, as gravity or acceleration plays a dominant role between the frames involved, and so breaks the symmetry. You cannot bring that symmetry back by simply calculating for the gravity and acceleration, as it was never there to begin with, because they were!

Am I missing something, or is this whole thing simply a straw man?

49. Hi SpeedFreek,

Thanks for your three replies. I must say, as I read through them I get differing feelings. Throughout, it is clear you know your relativity well. Then there are sections that preach to the converted as though you believe I do not understand certain things, when in fact, I do. I think a lot of this is caused by the different "language" we use.
Then there are parts that seem to contradict, like "you cannot subtract gravitational effects from Inertal ones", followed by the explanation of how you actually do this. ???
I meant simply to say that we can do exactly what you describe can be done regarding the assessment of Inertial effects.

I do not think this is a strawman. There really IS an issue;-

I am not contesting that transverse redshift would equate to gamma, if you can calculate out gravitational effects.
Well, it seems we are actually agreeing that which I have been trying to propose from the start, (unless I am missinterpreting your statement). I did not start out thinking about the details of H&F, I simply used the results to argue that inertial time dilation was real, as well as relative.
I then used this reality to argue that the clocks must be different between the two frames and then to conclude there must be Non symmetry of time dilation from a purely inertial perspective. I still believe this is correct.

Are you agreeing?

50. Originally Posted by kenhughes
Hi SpeedFreek,

Thanks for your three replies. I must say, as I read through them I get differing feelings. Throughout, it is clear you know your relativity well. Then there are sections that preach to the converted as though you believe I do not understand certain things, when in fact, I do. I think a lot of this is caused by the different "language" we use.
Then there are parts that seem to contradict, like "you cannot subtract gravitational effects from Inertal ones", followed by the explanation of how you actually do this. ???
I meant simply to say that we can do exactly what you describe can be done regarding the assessment of Inertial effects.
From my perspective, you are confusing the term inertial (which has a very specific meaning in Special Relativity) with kinematics, which includes all forms of motion including where external forces are present. I explained how you subtract gravitational time-dilation from kinematic time-dilation. The question is whether the kinematic effects are purely inertial or not.

Take the paradox of the twins, once again. Both frames are in relative motion but only one is inertial. If the at rest twin makes an observation of the accelerating twin, are we expected to believe he can mathematically cancel out that acceleration and assume the result is an observation of an inertial frame? Is that what you are saying here?

Let's go back to the beginning:

Originally Posted by kenhughes
Can anyone explain to me how time can be observed as slow from both the moving and stationary reference frames? Please don't give me more of the mainstream arguments, I understand those. Please explain why you would not observe a transverse doppler BLUEshift from the moving frame with the SR prediction of REDshift looking from the stationary frame.
Time can only be observed as slow from both frames, where the motion is relative, if those frames are purely inertial. If that were the case, we would observe transverse doppler redshift from both frames.

Originally Posted by kenhughes
I am not contesting that transverse redshift would equate to gamma, if you can calculate out gravitational effects.
Well, it seems we are actually agreeing that which I have been trying to propose from the start, (unless I am missinterpreting your statement). I did not start out thinking about the details of H&F, I simply used the results to argue that inertial time dilation was real, as well as relative.
I then used this reality to argue that the clocks must be different between the two frames and then to conclude there must be Non symmetry of time dilation from a purely inertial perspective. I still believe this is correct.

Are you agreeing?
No, as there does not exist a purely inertial perspective for the frames themselves. Their clocks reflect their relative paths through space-time, and the paths were not the same length. Whatever the cause of those paths (gravity or acceleration), calculating out what caused the paths to be those lengths will not change the paths the clocks took.

Sorry if some of my replies have been confusing, or wrongly worded (acceleration is tricky!) but this is all a little confusing.

51. Hi SpeedFreek,

Thanks again.

Can you help me with your definition of the term "inertial" then? Maybe this is the key for me and I want to understand exactly where my thinking is wrong or to understand how my ideas might be reconciled with the traditional understanding of relativity.

52. In the context of SR and the statement that time-dilation is symmetrical between inertial frames in relative uniform motion, an inertial frame is a frame where no forces are acting upon you (as having any force acting upon you would change your frame).

In GR, things are a little different. Here we have freely falling frames instead. In "flat" space, or where curvature is negligible, the situation is the same as in SR, but where there is significant curvature, free-falling objects can change speed in relation to each other, and thus their relative motion is not uniform.

The wiki article below is pretty good.

Inertial frame of reference - Wikipedia, the free encyclopedia

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