B Is special relativity incomplete?

[Herman Trivilino]

The premise that all inertial frames are equivalent is at the heart of SR, but it has never been experimentally verified, and indeed may not be verifiable.

That depends on what you mean by "verifiable". You will always be able to claim that any physical assertion is not verifiable because it's always possible that a counterexample will be found, disproving the assertion. That is a philosophical objection to the validity of scientific knowledge. But the fact is that scientists, engineers, and technicians have used the assertion to make advancements. The list of advancements is long, and includes things like proton therapy and the GPS.

The traveling clock will always be found to have logged less time than the Earth clock whether the two are brought together or the traveling clock is compared to a clock which has been placed at the destination (e.g., a planet in the same inertial frame as the Earth - not moving with rest thereto).

And the Earth clock will be found to have logged less time than the traveling clock. This is a fact that GPS engineers must take into account every minute of every day. If they didn't the GPS clocks would be so far out of sync that the system would no longer be able to reliably provide your location.

The Earth clock and destination clock, synchronized in their rest frame, will be out of sync with each other as observed by the traveler.

You are stuck in your thoughts, thinking that there is something special about Earth's frame of reference. One would think that after studying the history of science one would realize that being fooled in this way is something that keeps happening. Over and over again.

 

[yogi]

Einstein claimed in Part IV of his 1905 paper ..."if at points A and B ...stationary clocks viewed in the stationary system, are synchronous ; and if the clock A is moved with velocity v along a line AB to B, then on its arrival at B, the two clocks no longer synchronize, but the clock moved from A to B lags behind the other which has remained at B by (1/2)t(v^2/c^2)...t being the time occupied in the journey from A to B. It is at once apparent that this result still holds good if the clock moves from A to B along any polygonal line and also when the points A and B coincide. If we assume the result proved for a polygonal line is also true of a continuously curved line, we arrive at this result: If one of two synchronous clocks at point A is moved in a closed curve with constant velocity until it returns to A, the journey last t seconds, then by the clock which has remained at rest, the traveled clock on its arrival at A will be (1/2)tv^2/c^2 seconds slow.

Einstein's example considers curved constant velocity motion as a valid inertial frame. The experiments do not warrant the postulate that all inertial frames are equivalent - nor does the example require that the moving clock travel a straight path. A satellite in orbit is a perfectly valid inertial frame - the experiments are consistent therewith. There is no need to consider the Earth frame as special - it is convenient and as such it is almost always taken as the proper frame for conducting time dilation experiments. By whatever means the clocks are compared ... the results are not reciprocal - If the A clock lags behind B clock upon arrival at B, no amount of mathematical gymnastics can produce a different result - real time differences are a physical phenomena

Sadly, Einstein himself seems to have lost confidence in his first expose'. His later 1918 paper was a poor attempt to rationalize the traveling twin problem in terms of an artificial G field artificially introduced during turn around - what is more disturbing, several well respected Noble winners (including Feynman, Born and a few others) were influenced to endorse the proposition that GR is needed in order to solve the Twin problem. A curved path involves acceleration - but acceleration does not undermine the bases for the time difference, i.e., GR is not required or even appropriate.

In answer to post 51, GPS, satellite clocks are preset to compensate for the difference between gravitational potential and the kinetic energy associated with their orbital velocity. Thereafter, the clocks are updated periodically to correct for small drifts. (GPS clocks run faster because of their altitude and slower because of their velocity). The object of the corrections is to maintain sync for high accuracy positioning, While a GPS clock is a valid inertial frame, the object of the presetting and updating is to improve accuracy. The inertial frame of the satellite clock is different than the non rotating Earth centered frame, so corrections are required for the very reasons I have previously stressed, namely, all inertial frames are not equivalent.

 

[Dale]

Einstein's example considers curved constant velocity motion as a valid inertial frame.

No, he most certainly does not. You are misreading the passage.

The only reference frame used in that section is the "stationary frame". B remains at rest in this frame so the "stationary frame" is B's frame not A's. No calculation of any kind is done in A's frame. There is no claim or statement of any kind regarding how things would be from A's perspective or in A's frame.

Please go back and re read the passage and re think your analysis.

The experiments do not warrant the postulate that all inertial frames are equivalent

This is false and was already addressed above. Many experiments do validate the postulate.

In addition to all of the recent SME experiments there are also a lot of older experiments, many of which are detailed in http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

A satellite in orbit is a perfectly valid inertial frame - the experiments are consistent therewith ... While a GPS clock is a valid inertial frame

Not really. In scenarios involving tidal gravity there are no global inertial frames, only locally inertial frames. They are only practically inertial over a small enough region of spacetime.

 

[flexible_time]

Firstly, I would like to express my undoubted respect to the greatness of SR. In fact, I have no doubt about many facts that every experimental result has been exactly matched with what SR predicted. But what puzzles me is that if it is true that one conclusion of SR is that there is no “absolute rest” and absolute moving”, then the Einstein’s theory of special relativity seems to be self-contradiction in that he concluded the nonexistence of absolute motion of any matter only after assuming the existence of absolute moving entity, light. In my opinion, it is much close to the fact that, using the notion of absolute space and time, he found a brilliant way to express the relativistic relation between inertial frames to such an overwhelming extent. So here I will try to show what would be problematic with his conclusion on the nonexistence of absolute motion.In Einstein’s 1905 paper, he wrote

“Examples of this sort, together with the unsuccessful attempts to discover any motion of the Earth relatively to the “light medium,” suggest that the phenomena of electrodynamics as well as of mechanics possesses no properties corresponding to the idea of absolute rest.” It seems that this statement has the exact same meaning with "There is no answer to the question "is something moving or not" unless it is accelerating." because what really matters is the relativistic motion between inertial frame of references in the view point of relativity. So assuming SR view is correct, if two systems are both in uniform motion or “Galilean frames”, then I can conclude that two systems shows a perfect symmetry and are identical and “indiscernible” because they can declare each either rest or moving. Am I correct?If so far so good, then I question on the part of his paper quoted below.

“… when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. Take, for example, the reciprocal electrodynamic action of a magnet and a conductor. The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion. For if the magnet is in motion and the conductor at rest, there arises in the neighbourhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated. But if the magnet is stationary and the conductor in motion, no electric field arises in the neighbourhood of the magnet. In the conductor, however, we find an electromotive force, to which in itself there is no corresponding energy, but which gives rise—assuming equality of relative motion in the two cases discussed—to electric currents of the same path and intensity as those produced by the electric forces in the former case.”From the previous conclusion, if two systems, the conductor and the magnet have both infinite length so that one can move forever while the other at rest, then two systems must be identical to produce the indistinguishable results only because they can be either at rest or moving equally. But as he already wrote, there is actually a “sharp distinction” between the two cases and this seems to violate the conclusion of SR. If the prediction fails to match with the experimental result, it means that the conclusion of SR is problematic. It also leads to that we need to find a better way to resolve the mismatch between the prediction and the result. I think one way would be accepting the existence of absolute motion in the exact same manner with what Einstein postulated in his SR. Also I have a raw idea on how to get the state of “absolute rest” for a matter but want to check whether my reasoning so far will make sense to you before writing such a personal idea.Please correct me if I am wrong.

 

[Ibix]

You are misunderstanding your second quotation. The bit before your bolding is the experimental result - what happens depends only on the relative motion of the magnet and the conductor. The bit you bolded and the rest is an illustration of the problems with Maxwell's equations in Newtonian physics (which is the combination he means by "the customary view"). Namely that they imply a detectable absolute rest frame, or at least a detectable ether, which does not match experiment. This was a well-known issue that had been a hot topic of research for decades at that point. Einstein solved it by introducing what became known as relativity theory, bringing our theoretical understanding in line with our experimental knowledge.

Actually, if you want to get rid of the idea of no absolute motion you are going to have to go back to Galileo at least and rebuild all of physics from there. Please be aware that doing so on this forum would almost certainly be interpreted as a violation of the rules and get you banned, as would discussing whatever your personal idea is. PF is not the place for such a discussion.

 

[flexible_time]

what happens depends only on the relative motion of the magnet and the conductor.

My argument is that there is no way we can determine or predict what will happen if we are allowed to use only relative motion of the magnet and the conductor. If the theory cannot predict the future using only its postulates predefined, it can be considered as "incomplete" to me because it will require more information to determine the future. Using the scheme with the infinite lengthy magnet and conductor, in my opinion, the relativistic view will be unable to determine who is moving or resting unambiguously. If the magnet in uniform motion can be declared to be resting initially and some time later declared to be moving by observer like me and changing my mind between the resting magnet and the moving magnet do actually produce a significant difference, then I am forced to think there is the existence of free will.

This was a well-known issue that had been a hot topic of research for decades at that point. Einstein solved it by introducing what became known as relativity theory, bringing our theoretical understanding in line with our experimental knowledge.

I don't have any knowledge on that now and not sure his solution can solve my puzzlement in the above.

 

[Ibix]

My argument is that there is no way we can determine or predict what will happen if we are allowed to use only relative motion of the magnet and the conductor.

Then your argument is wrong. We routinely use relativity together with electromagnetic theory to predict the function of things like the LHC which relies on electromagnets to control the motion of relativistic particles.

Using the scheme with the infinite lengthy magnet and conductor, in my opinion, the relativistic view will be unable to determine who is moving or resting unambiguously.

Of course not. No such determination can be made by experiment, so relativity theory cannot be used to determine it either. This is not a failure of the theory any more than its inability to determine the properties of unicorns.

If the magnet in uniform motion can be declared to be resting initially and some time later declared to be moving by observer like me and changing my mind between the resting magnet and the moving magnet do actually produce a significant difference

It doesn't produce any significant difference. That's the point. The major issue with electromagnetism prior to Einstein was that the theory did predict significant differences between one particular rest frame and all others, but no such frame could be found experimentally despite increasingly ingeneous efforts. Einstein was reminding his readers of that fact prior to fixing the theory by extending the concept of relativity from just applying to space to applying to space and time.

 

[flexible_time]

Thanks for pointing out my misunderstanding in reading Einstein's paper.

But what do you think about another my observations?

"the Einstein’s theory of special relativity seems to be self-contradiction in that he concluded the nonexistence of absolute motion of any matter only after assuming the existence of absolute moving entity, light."

I think the assumption and the conclusion must show a consistency in the sense that relativistic result must be derived from the relativistic property. The conclusion on the nonexistence of absolute time and space which is derived from the existence of absolute velocity of light which is absolutely moving in space seems to be similar with a son denying the connection with his mother.
One more thing I would like to point out is that it is impossible to see only the notion of absolute moving without the notion of absolute rest. I think the opposite notion of moving is resting. So if light is absolutely moving in space, then we need to accept that there exists the notion of "absolute rest" because the notion for moving and rest is like the head and tail of a coin as we always can see the relative resting and relative moving between two inertial frames. If you agree with light is moving absolutely in space, you must also accept the notion of absolute rest. What do you think that?

Added more.

What the second postulate of SR, the constant speed c of light in every inertial frame of reference, imply is that there is the absolute time because it fits well with the Newtons's definition for the absolute time.

Quoting Newton,

“Absolute, true and mathematical time, of itself, and from its own nature flows equably without regard to anything external …”The constant speed of light means that light moves always and does change its position in time in every inertial frame of reference, in other words, time flows equably and the uniform time flow rate is defined as the unit distance r over the constant speed c of light independently of any perceiver or neighbors. This time flow rate in a true empty space is universal and does not change by anything so can be considered as "absolute".

 

[A.T.]

But what do you think about another my observations?

They are of no consequence for the correctness of quantitative predictions, thus are irrelevant to physics.

 

[russ_watters]

Thanks for pointing out my misunderstanding in reading Einstein's paper.

But what do you think about another my observations?

"the Einstein’s theory of special relativity seems to be self-contradiction in that he concluded the nonexistence of absolute motion of any matter only after assuming the existence of absolute moving entity, light."

I think the assumption and the conclusion must show a consistency in the sense that relativistic result must be derived from the relativistic property. The conclusion on the nonexistence of absolute time and space which is derived from the existence of absolute velocity of light which is absolutely moving in space seems to be similar with a son denying the connection with his mother.

You've stated this several times and it has been explained to you that (and how) it is wrong several times. I'm not sure what else can be said - it is up to you whether you want to believe the reality or not.

 

[flexible_time]

You've stated this several times and it has been explained to you that (and how) it is wrong several times. I'm not sure what else can be said - it is up to you whether you want to believe the reality or not.

Sorry if I did something wrong. I did not know there were enough explanations provided and I was thinking to keep asking a new question which is not stated before although the purpose is the one to see the possibility for the existence of absolute time and space.

 

[flexible_time]

So, assuming the same speed of light in this frame too, how can you get the events of the pulse reaching the two ends be simultaneous? Please note that when we say the speed of light is constant we mean wrt the frame where you measure it, not wrt the light source.

What if I move the position of a pulsing light slightly from middle to the leading end after considering the velocity of the rod relative to light? In this way, I think it would be possible to get the events of the pulse reaching to two ends be simultaneous measured with regard to my frame.

These experimental results have been confirmed to such an overwhelming extent that there is no room left for doubt.

I don't agree the validity of SR is confirmed in the region of singularity point such as black hole. If not confirmed there, then I believe that there should be room left for doubt although it may not be possible to test in practical point of view.

 

[A.T.]

I don't agree the validity of SR is confirmed in the region of singularity point such as black hole.

SR fails way outside the black hole. That's why GR was introduced.

 

[Ibix]

One more thing I would like to point out is that it is impossible to see only the notion of absolute moving without the notion of absolute rest. I think the opposite notion of moving is resting. So if light is absolutely moving in space, then we need to accept that there exists the notion of "absolute rest" because the notion for moving and rest is like the head and tail of a coin as we always can see the relative resting and relative moving between two inertial frames. If you agree with light is moving absolutely in space, you must also accept the notion of absolute rest. What do you think that?

I think you need to read the paper by Pal that I linked to earlier. He shows that the principle of relativity leads to either Newton or Einstein (and no other option) without invoking a constant speed of light. The idea of a constant speed falls out of the maths. So no, the two ideas are not contradictory.

The rest of your post is you attempting to reason verbally about something best described by maths. Try learning the maths; then you'll understand the theory, not the caricature you keep describing.

 

[russ_watters]

What is concerning is that you don't seem to be acknowledging the simple explanation you have been given - that light behaves differently from objects with mass or sound. I'm not sure that you get that what you think is a contradiction, if it were really a problem it would show up in experiments. In fact it is the other way around: the idea that light behaves same as sound or objects was causing problems didn't work. That is the whole reason special relativity was developed.

You seem to be taking a posture that you are trying to argue around this idea rather than learning it. That is not what PF is for and this posture is preventing you from learning how it really works.

 

[Ibix]

What if I move the position of a pulsing light slightly from middle to the leading end after considering the velocity of the rod relative to light? In this way, I think it would be possible to get the events of the pulse reaching to two ends be simultaneous measured with regard to my frame.

Of course. But then they won't be simultaneous in the other frame.

 

[flexible_time]

SR fails way outside the black hole. That's why GR was introduced.

Yes, thank for correcting me. But my understanding is that GR , another theory of relativity supporting only the relativistic nature of time and space is not perfect to describe all behavior around BH so I still think there may be room for doubt.

 

[Dale]

This thread is closed.

This forum is for people who want to learn about relativity, not for people who wish to ignore the evidence and explanations to cling to an outdated philosophy.