Relativity without the aether: pseudoscience?

[JesseM]

I wasn't suggesting anything by that question since I've yet to know what this theory you're speaking of is.

Aether seems not to be describing an alternate theory at all, but just a different set of coordinate systems for describing a spacetime which obeys exactly the same laws as the one in SR. As in relativity, each observer can assign coordinates to events using a network of rulers and clocks, but instead of each observer synchronizing their clocks using the assumption that light travels at c in their own rest frame, only one observer synchronizes his clocks this way, and all other observers synchronize their clocks in such a way that their definition of simultaneity agrees with that preferred observer. If x and t are the coordinates assigned to an event by the preferred observer, then another observer moving at v along his access will assign the same event coordinates x' and t', with the coordinates related by the following "LET transformation":

x' = (x - vt)/\sqrt{1 - v^2/c^2}
t' = t \sqrt{1 - v^2/c^2}

You can compare this with the Lorentz transformation:

x' = (x - vt)/\sqrt{1 - v^2/c^2}
t' = (t - vx/c^2) / \sqrt{1 - v^2/c^2}

Most people who use the term "Lorentz ether theory" would define the theory as saying there's an actual physical substance called "ether" and that the preferred observer should be at rest with respect to this ether, but Aether seems not to think this assumption is important, so he isn't making any new physical assumptions at all, he's just using a different set of coordinate systems. You can see, though, that if there was such a thing as ether, and all rulers moving relative to that ether shrunk by \sqrt{1 - v^2/c^2} while all clocks moving relative to that ether had their ticks extended by 1/\sqrt{1 - v^2/c^2}, then if all observers synchronized their clocks using the Einstein synchronization procedure, different observers' coordinate systems would be related by the Lorentz transform and there'd be no way to actually detect which frame was the ether's rest frame, so such a universe would be empirically equivalent to one where there is no ether but the laws of physics exhibit Lorentz-symmetry. I elaborated on this empirical equivalence a little more in the first two paragraphs of post #36.

 

[Aether]

Aether seems not to be describing an alternate theory at all, but just a different set of coordinate systems for describing a spacetime which obeys exactly the same laws as the one in SR. As in relativity, each observer can assign coordinates to events using a network of rulers and clocks, but instead of each observer synchronizing their clocks using the assumption that light travels at c in their own rest frame, only one observer synchronizes his clocks this way, and all other observers synchronize their clocks in such a way that their definition of simultaneity agrees with that preferred observer. If x and t are the coordinates assigned to an event by the preferred observer, then another observer moving at v along his access will assign the same event coordinates x' and t', with the coordinates related by the following "LET transformation":

x' = (x - vt)/\sqrt{1 - v^2/c^2}
t' = t \sqrt{1 - v^2/c^2}

You can compare this with the Lorentz transformation:

x' = (x - vt)/\sqrt{1 - v^2/c^2}
t' = (t - vx/c^2) / \sqrt{1 - v^2/c^2}

Most people who use the term "Lorentz ether theory" would define the theory as saying there's an actual physical substance called "ether" and that the preferred observer should be at rest with respect to this ether, but Aether seems not to think this assumption is important, so he isn't making any new physical assumptions at all, he's just using a different set of coordinate systems. You can see, though, that if there was such a thing as ether, and all rulers moving relative to that ether shrunk by \sqrt{1 - v^2/c^2} while all clocks moving relative to that ether had their ticks extended by 1/\sqrt{1 - v^2/c^2}, then if all observers synchronized their clocks using the Einstein synchronization procedure, different observers' coordinate systems would be related by the Lorentz transform and there'd be no way to actually detect which frame was the ether's rest frame, so such a universe would be empirically equivalent to one there is no ether but the laws of physics exhibit Lorentz-symmetry. I elaborated on this empirical equivalence a little more in the first two paragraphs of post #36.

That seems to be a fair summary, thanks.

 

[pmb_phy]

... but instead of each observer synchronizing their clocks using the assumption that light travels at c in their own rest frame, only one observer synchronizes his clocks this way, and all other observers synchronize their clocks in such a way that their definition of simultaneity agrees with that preferred observer. ...

That's nuts! There is no meaning to synchronizing one clock! I knew there was a good reason I dropped out of this thread!

Pete

 

[JesseM]

... but instead of each observer synchronizing their clocks using the assumption that light travels at c in their own rest frame, only one observer synchronizes his clocks this way, and all other observers synchronize their clocks in such a way that their definition of simultaneity agrees with that preferred observer. ...

That's nuts! There is no meaning to synchronizing one clock! I knew there was a good reason I dropped out of this thread!

Pete

What are you talking about? I said clocks plural, in all 3 instances that you quoted above. The whole basis of SR is the idea of each observer synchronizing their clocks using light signals, it's right there in Einstein's original 1905 paper.

 

[Aether]

That is the most incorrect statement that I've seen posted on the internent in months. Where did you get this idea from?

I would like to see you try and refute that. However, the main purpose for this post is to ask that you delete the link to my website from your post. I only intended for that to remain visible long enough for you to download the paper if you were interested.

 

[Aether]

Both theories postulate Minowski geometry. However, SR makes no additional postulates, defining everything else from the geometry.

However, a LET requires at least one additional postulate about absolute simultaneity, since that cannot be defined from the geometry.

This sounds like a potentially convincing argument, Hurkyl. I have never seen SR described that way anywhere else though; do you know of a source that teaches SR from that perspective? My objection to "SR without the aether" may arise entirely from the difference between what you wrote and the "two postulates" of SR. Am I likely to find statements like "experiments prove that the speed of light is a constant" in such a text?

 

[DrGreg]

If you assume SR is correct, you can come up with some expressions for momentum and energy relative to LET co-ordinates by application of the transform equations. But if you ignore SR and try to calculate momentum and energy some other way, how do you find the answer? How, for example, do you prove that, relative to the ether, the relativistic form p=\gamma_u m u should be used instead of p= m u?

I have today at long last been able to view of copy of the Mansouri-Sexl papers. The conclusion of paper I is

"A theory maintaining the concept of absolute simultaneity can be obtained ... which is ... empirically equivalent to special relativity, as least as far as kinematics is concerned." (My emphasis)​

I think that supports my point about the difference between kinematics and dynamics.

They also make the point that Einsteinian clock synchronization is the same as synchronization via ultraslow clock transport, in the context of SR and what we have been calling "LET".

By the way, I'm no longer sure whether it is correct to describe their transform as "Lorentz Ether Theory" -- there may be several competing ether theories in circulation.

I think I will have more to say once I've read all three papers in more detail.

 

[Hurkyl]

I have never seen SR described that way anywhere else though; do you know of a source that teaches SR from that perspective?

No -- my perspective is pretty much a synthesis of everything I've leared (from a wide variety of sources), and my working out details on my own as well.

There has to be a textbook on Minowski geometry around someplace, though -- I don't know of any, though.

 

[pmb_phy]

I would like to see you try and refute that. However, the main purpose for this post is to ask that you delete the link to my website from your post. I only intended for that to remain visible long enough for you to download the paper if you were interested.

At the time I wrote that assertion it was at a time when I made a false assumption in that the term "LET" of yours meant something other than what I assuimed it meant. I therefore retract my assertion since I don't want to read that article on LET that you linked to. It may be more widely used than that paper

When you explained to me what you meant by LET I then chose to bow out of this conversation since I'm not in the mood for looking into what appears to be bad physics. Please don't try to analyze my statement here because I have nothing against the notion of looking more deeply into what "appears" to be wrong, since it could very well be right. But I have to make choices on how I spend my time. The problem is sitting in this chair with my back in so much pain. If you're curious as to what my back looks like after the removal of the herniated disk then see the photo in the first post at - http://ubb-lls.leukemia-lymphoma.org/ubb/Forum14/HTML/001089.html

I still do physics now but only in those areas I love. At this time I have zero interest into looking into this LET thing. Hence the reason I bowed out of this conversation. I only came back because I neglected to state that because something is not science it doesn't mean that it should be called pseudoscience. Religion is not science but it'd be wrong to call religion pseudoscience. A wrong theory is not pseudoscience simplyt because its wrong. It must satisfy other criteria which lies beyond the science itself and lies within the minds of the holders of the theory. Its a weird thing and too drenched in debateable terminology to want to get into. There's a book called "Science and Unreason" by Radner and Radner. It was required reading in my philosophy of science course in college. I highly recommend this text for those who wish to learn what pseudoscience is.

As far as removing that link - No can do. First off you shouldn't post in open forum something which you don't want to keep there permenently. It requires me to do things like this where you want me to dig through old posts and delete something I quoted. I did look into removing the link but its too late. A post can only be edited for a day or two.

Pete

 

[DrGreg]

To anyone who is interested: I have found a one-page summary of the Mansouri-Sexl framework that Aether refers to here: http://relativity.livingreviews.org/Articles/lrr-2005-5/articlesu9.html , on the "Living Reviews in Relativity" website. (The notation used in the summary is not quite the same as the notation that M&S use themselves.)

The framework is to interpret the results of experiments testing the accuracy of Special Relativity. It assumes there is at least one frame (the "ether frame") in which the speed of light is isotropic and takes the view that the transformation to other frames is an unknown linear transform, with velocity-dependent coefficients that are to be determined experimentally. The results of experiments that had been performed before publication in 1977 are then analysed to determine how close the coefficients must be to the Lorentz transform.

In the course of their analysis, M&S make the point that there is an arbitrary choice of clock synchronization to be made. Their method effectively ignores any effects that are due to the choice of synchronization.

The particular transformation that Aether has been discussing in this forum (which we have been describing as "LET") is one that can be implemented as "synchronization to the ether" (if you have chosen an ether) but which is, essentially, mathematically equivalent to Special Relativity. This is really the point - the two formulations come from different sets of assumptions but come to essentially the same conclusion, in the sense that one formulation can be mathematically transformed into the other. The two "theories" stand and fall together - they're either both true or both false.

If Aether is hoping to find something to favour an ether theory over SR, it would have to take the more generalised form discussed by Mansouri-Sexl rather than the particular form that has been quoted.


References:

Mansouri, R., and Sexl, R.U., “A test theory of special relativity. I - Simultaneity and clock synchronization”, Gen. Relativ. Gravit., 8, 497-513, (1977).

Mansouri, R., and Sexl, R.U., “A test theory of special relativity. II - First Order Tests”, Gen. Relativ. Gravit., 8, 515-524, (1977).

Mansouri, R., and Sexl, R.U., “A test theory of special relativity. III - Second Order Tests”, Gen. Relativ. Gravit., 8, 809-814, (1977).

Bluhm, R., "Breaking Lorentz Symmetry", Physics World, March 2004.

 

[Aether]

...I'm not in the mood for looking into what appears to be bad physics. Please don't try to analyze my statement here because I have nothing against the notion of looking more deeply into what "appears" to be wrong, since it could very well be right. But I have to make choices on how I spend my time. The problem is sitting in this chair with my back in so much pain.

OK, I hope to run into you again sometime on a topic that is of more interest to you. Best wishes on a speedy recovery.

 

[Juan R.]

Special relativity (SR) SR and Lorentz ether theory (LET) are empirically equivalent systems for interpreting local Lorentz symmetry. These two theories are equally valid, but it is not possible (so far) to demonstrate the truth or falseness of the postulates of either theory over the other by experimentation. Still, a superstition persists in the minds of many that somehow "SR is true, and LET is false". Why isn't "relativity without the aether" fairly described by the term "pseudoscience"?


pseudoscience - Refers to anybody of knowledge or practice which purports to be scientific or supported by science but which is judged by the mainstream scientific community to fail to comply with the scientific method.

scientific method n - The principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to demonstrate the truth or falseness of the hypothesis, and a conclusion that validates or modifies the hypothesis.

su·per·sti·tion n An irrational belief that an object, action, or circumstance not logically related to a course of events influences its outcome.

1) A belief, practice, or rite irrationally maintained by ignorance of the laws of nature or by faith in magic or chance.

2) A fearful or abject state of mind resulting from such ignorance or irrationality.

3) Idolatry.

I do not argue in favor of or against the aether. In fact, i am a bit confused about the need or not of an aether. Simply i will cite a bit of history that has great physical consequences but that is ignored in typical textbooks.

In a letter to Lorentz dated 17 June 1916, Einstein wrote:

I agree with you that the general relativity theory admits of an ether hypothesis as does the special relativity theory.

According to Galina Granek, in 1920 at a lecture in Leiden [Einstein, A. (1920) Äther und Relativitätstheorie. Lecture Presented on 5th May, 1920 in the University of Leyden (Berlin: Springer).], Einstein explained why a revised notion of the ETHER was required in physics. He REPEATED Poincare's claims of 1900, according to which AETHER is required in order that movements do not take place with respect to empty space.

does the Aether exist?

I only know that MM experiments and similar cannot detect Poincaré aether (which is not the same that the Lorentz aether)?

 

[derz]

The mathematics of SR work without the assumption of an aether, so why would it be pseudoscience?

I believe that with an "aether" Einstein meant the dynamic spacetime of GR that has properties hidden from us, i.e. geometry.

 

[Jimmy Snyder]

scientific method n - The principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to demonstrate the truth or falseness of the hypothesis, and a conclusion that validates or modifies the hypothesis.

Even though I attributed this quote to Aether, I assume that it was meant to be a quote from some other source. I don't buy this description of the scientific method. It is overly enthusiastic concerning the ability to demonstrate truth. My view conforms to that of this site:

http://www.philosophypages.com/lg/e15.htm

Here is a quote from that site:

Although it always remains impossible in principle to prove the truth of a scientific hypothesis, it is possible to compare the distinct hypotheses involved in rival explanations of the same event.

I think discussions of the relative merits of differing hypotheses would go smoother if this last quote were kept in mind. Calling your opponent supersticious just because they don't share your own certainty seems counterproductive to me.

 

[Aether]

The mathematics of SR work without the assumption of an aether, so why would it be pseudoscience?

I believe that with an "aether" Einstein meant the dynamic spacetime of GR that has properties hidden from us, i.e. geometry.

It is not valid to claim that the constancy of the speed of light is proven "by experiment", or that "experiments prove" that SR is right and that LET is wrong. The "Consistency of the speed of light" thread is where examples of such claims can be seen, and where my question of "pseudoscience" comes from. Take note of where the speed of light is claimed to be constant in other than an "inertial reference frame" (some people say "all frames of reference" for example, which is wrong). Also take note where people claim that "experiments prove" that the speed of light is a constant.

I am concerned by such claims because they appear to be flat wrong, yet just about everyone else in the "constancy of the speed of light" thread seemed to agree (at that time at least) that these claims were clearly right and that the claims that I was making to the contrary (from Mansouri-Sexl) were clearly wrong.

SR is valid only within the context of intertial reference systems. To establish an inertial reference system one must start out by synchronizing all of the clocks at rest in the system so that experiments will measure the same speed of light in all directions. This particular clock synchronization convention is where the relativity of simultaneity comes from. There are other equally valid ways to syncrhonize clocks; in particular the clock syncrhonization of LET maintains absolute simultaneity.

Relativity per se is not pseudoscience when it is kept within the context of inertial reference systems.

 

[Aether]

Calling your opponent supersticious just because they don't share your own certainty seems counterproductive to me.

How is it counterproductive? I have clearly demonstrated that many people have an irrational belief that a circumstance (e.g., the constancy of the speed of light) not logically related to a course of events (e.g., an experiment) influences its outcome. This reads on the definition of "superstition" that I quoted. Now I am faced with a choice: 1) keep this to myself, and risk either: a) going through the rest on my own life with the wrong impression, or b) allowing my brothers and sisters to go through life believing in a superstition; or 2) ask this question so that we all may reason together.

 

[derz]

SR is valid only within the context of intertial reference systems

Well, there is always the general theory of relativity that deals with accelerating frames.

I don't believe that the speed of light is contant because everybody says so, but because it is a logical consecuence (spelling?) of the fact that there is no absolute frame of reference. And that is what can be concluded from the MM-experiment.

 

[Hurkyl]

SR is valid only within the context of intertial reference systems.

Somewhat misleading -- just like with Newtonian physics, the formulae of SR may be modified so that they would apply to any generalized coordinate system.

 

[DrChinese]

1. The idea that the constancy of the speed of light can't be proven by experiment?

2. OK, but I didn't say that there was anything wrong with science, only with relativity.

1. That c is a constant has been verified any number of times, in any number of ways. There are some people who say there are loopholes in ANY experiement that does not agree with their hyposthesis. For example: Caroline Thompson does it with Bell tests; and apparently you take up the issue similarly with c.

2. You have not shown a single prediction of SR which is inconsistent with accepted experiment. Here's your chance to show us wrong.

By the way, shouldn't this thread be getting close to end of its run?

 

[Jimmy Snyder]

In SR, the constancy of the speed of light is a postulate. It's something that is taken for granted, not something that is proven. How can you tell the difference between someone who superstitiously believes that the speed of light is a constant, and someone who is simply following the consequences of a postulate?

 

[JesseM]

It is not valid to claim that the constancy of the speed of light is proven "by experiment", or that "experiments prove" that SR is right and that LET is wrong.

It's valid in the sense that experiments prove that the laws of physics are Lorentz-symmetric, which means that if you use any type of "natural" coordinate system involving rulers and clocks moving inertially and clocks synchronized using what Mansouri and Sexl call "system-internal clock synchronization", then you will find that the speed of light is constant. The fact that this stuff is left implicit rather than made explicit doesn't make it "invalid", although it may make the claim insufficiently spelled-out.

Question: do you think it's valid to say that "experiments demonstrate that the speed of the Earth's rotation at the equator is 1670 km/hour"? This statement also makes the same sort of implicit assumptions about using an inertial coordinate system with a system-internal clock synchronization method, doesn't it? Would you say this means the statement actually has no basis in experiments?

 

[Aether]

By the way, shouldn't this thread be getting close to end of its run?

OK. I'll answer any direct questions to me, but otherwise let everyone else have the last word.

How can you tell the difference between someone who superstitiously believes that the speed of light is a constant, and someone who is simply following the consequences of a postulate?

If they insist that the constancy of the speed of light is "proven by experiment", then they are mistaken. If they understand that this is how inertial reference systems are defined, and that the constancy of the speed of light can't be the subject of an experiment in this context, then they are correct. If they also say something to the effect that without evidence of a violation of local Lorentz symmetry, then it is usually more convenient to treat the speed of light as a constant, then that's also correct.

 

[Jimmy Snyder]

And what if they say it's a postulate?

 

[Aether]

Question: do you think it's valid to say that "experiments demonstrate that the speed of the Earth's rotation at the equator is 1670 km/hour"?

Yes.

This statement also makes the same sort of implicit assumptions about using an inertial coordinate system with a system-internal clock synchronization method, doesn't it?

No. This looks like a one-clock experiment, and there would be no need to synchronize clocks.

Would you say this means the statement actually has no basis in experiments?

No.

And what if they say it's a postulate?

I'm not exactly sure what you're asking, but if they say that "the speed of light c is the same in all inertial frames" is a postulate, then that is true.

 

[JesseM]

No. This looks like a one-clock experiment, and there would be no need to synchronize clocks.

The average speed for a full rotation might be a one-clock experiment, but the instantaneous speed at any given moment would not be. But to avoid this issue, how about a statement about velocities that does not involve circular paths, like "the Andromeda galaxy is approaching our own galaxy at a speed of 68 kilometers per second"--would you say this has any more or less basis in experiment than the statement that the speed of light is constant?

 

[Jimmy Snyder]

Well, are you proponents of SR unaware that Aether is baiting you? There is no need to prove that the speed of light is a constant. SR has already proved its worth by getting correct numerical results where Newtonian theory fails, for instance in calculating the half-life of particles in particle accelerators. The ball is in the court of your opponents. They need to come up with an experiment in which SR predicts the wrong number. Getting you to try and prove that your postulates are true is a distraction meant to cover up for this shortcoming on their part.

 

[DrGreg]

Here are three postulates:

1. All cats are completely black
2. All cats are completely white
3. At least one cat exists

There are two questions you can ask about these postulates. Are they mutually consistent? Is there any experimental evidence to support or disprove them?

I suggest there is overwhelming experimental evidence that 1 and 2 are false and 3 is true.

But if we ignore the evidence and simply consider the internal logic of my "theory", you will see that any two of the three postulates are compatible, but all three taken together are incompatible.

So there are potentially two ways to "disprove" a postulate: in one sense, provide experimental counter-evidence, or in another sense, show its logical incompatibility with other postulates (or even with itself).

Einstein's postulate of the constancy of the speed of light cannot be disproved logically, and nobody has yet been able to disprove it experimentally.

However, much of the argument in this thread has been about whether there is an alternative set of postulates that is compatible with experiment (there is), and whether such an alternative set is better or worse than Einstein's. Most of us, including me, think Einstein's is by far the best (for example, by application of Occam's Razor), but Aether disagrees with us.

 

[ZapperZ]

Here are three postulates:

1. All cats are completely black
2. All cats are completely white
3. At least one cat exists

There are two questions you can ask about these postulates. Are they mutually consistent? Is there any experimental evidence to support or disprove them?

I suggest there is overwhelming experimental evidence that 1 and 2 are false and 3 is true.

But if we ignore the evidence and simply consider the internal logic of my "theory", you will see that any two of the three postulates are compatible, but all three taken together are incompatible.

So there are potentially two ways to "disprove" a postulate: in one sense, provide experimental counter-evidence, or in another sense, show its logical incompatibility with other postulates (or even with itself).

Einstein's postulate of the constancy of the speed of light cannot be disproved logically, and nobody has yet been able to disprove it experimentally.

However, much of the argument in this thread has been about whether there is an alternative set of postulates that is compatible with experiment (there is), and whether such an alternative set is better or worse than Einstein's. Most of us, including me, think Einstein's is by far the best (for example, by application of Occam's Razor), but Aether disagrees with us.

I think you have hit the issue right on its head.

I see NO COMPELLING REASON why I should abandon a well-tested theory for all of these alternative ideas, when the best they can do is agree with SR. We certainly did not adopt QM simply because it can provide an alternative view of our world that we much "prefer" than classical mechanics. And for me, personally, there is no more compelling evidence than a clear experimental observation. Till we have that, I find all of these arguments to be rather moot.

Zz.

 

[Jimmy Snyder]

I'm sorry for completely mischaracterizing the nature of the discussion in this thread. Is the issue that the following two arguments are on equal footing?

1. No one has detected a dependence of the speed of light on the motion of the emiter relative to the observer, therefore the dependence does not exist.

2. No one has detected the luminiferous aether, nonetheless the aether does exist.

I hope I have not mischaracterized a second time, but if I have, please straighten me out.

 

[Aether]

"the Andromeda galaxy is approaching our own galaxy at a speed of 68 kilometers per second"--would you say this has any more or less basis in experiment than the statement that the speed of light is constant?

The basis in experiment for this statement is that the ratio of wavelengths for signals coming from the Andromeda galaxy compared to like signals on Earth is observed to be 0.99977. The speed of 68 km/s comes from running this observed ratio though the relativistic Doppler equation. The ratio of wavelengths is proven by experiment, but the velocity depends on one's choice of coordinate system in the same way that the speed of light does; therefore, I suspect that the ratio \beta =v/c=0.000227 could probably also be considered as being proven by experiment.