Debunking Nimtz
in [Relativity]
|
Prev: GETTING RID OF EINSTEIN RELATIVITY
Next: USM
From: Tom Roberts on 4 Sep 2007 00:04 Tom Van Flandern wrote: > GR has had two different physical interpretations since its > inception, but you have been taught only one of them and wish to insist > that one is the only one entitled to be called "GR". I know of both "interpretations", and as I have said before, the "forces on a flat background" approach cannot be GR, because it cannot describe all the solutions of the field equations of GR. I know they are LOCALLY equivalent, but that is not sufficient for it to be entitled to be called "GR". > Nobel Laureate Richard Feynman's [...] I know this. But again, spin-two fields on a flat background cannot describe all of the solutions of the field equation of GR. And, of course, it abandons one of the hallmarks of GR: background independence. >> [Roberts]: The theory consisting of fields ON A FLAT EUCLIDEAN 3-SPACE >> is not GR. That is, it cannot possibly include all the solutions of >> the actual equations of GR. It is, as I said, merely an APPROXIMATION >> to GR. > > What you call "GR" and what Feynman and I call the geometrical > interpretation of GR cannot test its four basic predictions > (light-bending, redshift, radar delay, perihelion advance) because > testing it requires converting your perfect theory with exact equations > into approximate equations of motion in the flat Euclidean space where > all astronomical observations are made. Approximations to a theory are OK, as long as one realizes they are approximations and their necessary conditions are realized in the physical situation. > Moreover, the interpretation you call "GR" was experimentally > falsified by the laser interferometer experiments, as explained in my > last message and which you chose to ignore. That experiment explicitly > showed that the weak equivalence principle ("gravity is just geometry") > is false. Experiments cannot falsify interpretations. > [...] magic p...] Your only way out of this dilemma in physics is to > postulate some kind of tangible, material entity in the vacuum or in > fields to act as a cause and carry momentum. No, it apparently is YOUR "only way out". Because YOU are the one who seems to be constrained by pre-20th century notions of causality and such. I have no problem with geometry affecting physics, because I know that physics and geometry cannot possibly be divorced. I repeat: what "physical cause" do you think makes light travel in a straight line? Note you must first provide a "physical" description of a straight line -- if you fall back on a geometrical description you are abandoning your own claims. > Defend your claim by pointing to a reference or > making an argument showing how the geometric interpretation (your "GR") > has been tested against observations without going through what you call > "an approximation" that involves flat Euclidean space. There's no need: in regions with small fields it has been shown that one can use a Minkowski background with negligible error. The problem is not with using approximations, the problem is with your insistence that a specific approximation is the whole theory. It isn't. >> [Roberts]: the EQUATIONS make aberration "disappear". > > True. But that is because they contain no propagation delay for > propagating gravitational forces, and the absence of propagation delay > is the equivalent of setting propagation speed to infinity and > aberration to zero. IN THE APPROXIMATION. The actual equations of GR do not permit this. You keep confusing the approximation with the theory. DON'T DO THAT! > Carlip's argument is that propagation delay wasn't omitted, but was > cancelled by a "velocity-dependent force". He takes the instantaneous > force vector in the equations and resolves it into a retarded force > vector plus a cancellation vector that depends on velocity, thereby > nullifying aberration. Vigier and I showed that the Moon could not tell > a tidal force from a propagation delay force because both look like a > displacement of Earth's center of mass to the Moon. The Moon therefore > has no way to respond to one force and ignore the other. Words. Words. Words. Einstein showed that the equations of GR reduce to the equations of Newtonian gravitation in the appropriate limit. Carlip showed how it is that the delayed interactions of GR can APPEAR to be the instantaneous action-at-a-distance of NG. The moon, of course, "knows" none of this, and behaves however it is that she behaves. The issue is about how we humans MODEL her behavior. The equations of GR do so quite accurately. And Newtonian gravitation does so also. In GR the interactions are delayed, and in NG they are instantaneous, yet both accurately model the behavior observed. Therefore the claim that "gravitational force propagates much faster than c" is THEORY DEPENDENT, and does not apply to GR. >> [Roberts]: THE EQUATIONS OF GR can encompass manifolds with topologies >> and curvatures completely incompatible with a flat 3-space. > > And where is any kind of test of those differences to show that your > "GR" is correct or better than the flat 3-space theory that everyone but > you calls "the field interpretation of GR"? I know of none. I was taking issue with your claim that you were using GR. You aren't. You are using what is at best an approximation or a subset of GR. > I claim there is no such > test. I also know of none. But that does not change the fact that you are NOT using GR. The theory you are using is as well supported by the experiments as is GR, AFAIK. > Many, many authors since then have made the same basic point: The > equations of GR, when converted to equations of motion for 3-space > acceleration for the purpose of testing against observations made in a > Euclidean space, can be interpreted as geometry or as classical forces > with refraction in an optical medium. ONLY in situations in which the approximation is valid. You keep confusing the approximation with the theory. DON'T DO THAT! > Do you reject all this physics, or choose to ignore it? I reject your claim that you are using GR. > But the relevant point is this. I claim your "GR" has no equations > that can be tested experimentally without going through the field > interpretation, "approximations", and Euclidean space. Hmmm. I believe all current tests are of that sort, but know of no reason in principle that this can't change. But I DO know of reasons why that 'field interpretation, "approximations", and Euclidean space' is NOT GR: there are solutions to the field equations of GR that do not admit a Euclidean 3-space, and therefore your approach cannot be applied. > It does not matter if this process is done explicitly, as in most > textbooks (e.g., MTW p. 1095); or implicitly by numerical iterations. > Either way, you have left your world of equations behind and entered my > world of forces and astronomical observations made in Euclidean space. I repeat: approximations are OK, as long as one realizes they are approximations, and makes sure the requirements of those approximations are valid. That is a necessary point you seem to have forgotten. > you still have not specified what > it would take for you to agree (if it is true) that interpreting > solutions to the GR field equations in terms of classical forces and > Euclidean space might a better description of reality than your > geometric way of interpreting those same equations. To do that, you must show that "interpreting solutions to the GR field equations in terms of classical forces and Euclidean space" is the same as those field equations. And that simply is not possible: there are many known solutions to the field equation of GR that do not admit a Euclidean 3-space. I have no problem doing this APPROXIMATELY (i.e. locally), but an approximation to a theory is NOT the theory itself. Unfortunately, all experiments so far are in situations where that approximation is more than adequate, so there is no available test that distinguishes the approximation from the full theory. Tom Roberts
From: Tom Van Flandern on 7 Sep 2007 15:32 Tom Roberts writes: >> [tvf]: GR has had two different physical interpretations since its >> inception, but you have been taught only one of them and wish to insist >> that one is the only one entitled to be called "GR". > [Roberts]: I know of both "interpretations", and as I have said before, > the "forces on a flat background" approach cannot be GR, because it cannot > describe all the solutions of the field equations of GR. I know they are > LOCALLY equivalent, but that is not sufficient for it to be entitled to be > called "GR". I was taught the field interpretation of GR first, with its instantaneous forces in Euclidean space, in my celestial mechanics courses in the Ph.D. program at Yale in the 1960s. You were taught the geometric interpretation of GR, most probably because you were educated after the early 1970s when MTW's "Gravitation" first popularized that approach. What makes you the Lord of terminology to declare that what you were taught is "entitled to be called GR", and what I was taught is not? IMO, you had teachers who didn't know there relativity history or who had an agenda. > [Roberts]: spin-two fields on a flat background cannot describe all of the > solutions of the field equation of GR. That is merely a mathematical statement. Equations often contain possibilities that physics cannot, such as singularities, imaginary solutions, etc. Einstein himself argued that the Schwarzschild singularity in the solution to his equations did not represent real physics. But Einstein's student Wheeler invented "black holes" after Einstein's death and built a career on that and similar extensions of the theory. Most of these post-Einstein ideas have yet to be tested. Some of the "string theory" ideas aren't even testable. But calling them "GR" is donning Einstein's mantle to further one's own career or interests -- which of course is just the way many leaders in the field got to where they are now. Those who don't know their relativity history are doomed to be duped by such people. > [Roberts]: And, of course, it abandons one of the hallmarks of GR: > background independence. If you mean "aether independence", once again, you do not know history. Einstein often invoked the aether and insisted that GR had to meet physical and mechanical constraints that were not in his equations. Here's one of many such quotes: "... there is a weighty argument to be adduced in favor of the ether hypothesis. To deny the existence of the ether means, in the last analysis, denying all physical properties to empty space. But such a view is inconsistent with the fundamental facts of mechanics." A. Einstein, �ther und Relativit�tstheorie: Rede gehalten am 5. May 1920 an der Reichs-Universit�t zu Leiden, Springer, Berlin (1920). > [Roberts]: Approximations to a theory are OK, as long as one realizes they > are approximations and their necessary conditions are realized in the > physical situation. I am equally entitled to argue that the force equations are the real GR because they have been tested by observations; whereas the field equations are then just an approximation to what has been tested, and have little practical value until they are converted back to force equations. >> [tvf]: Moreover, the interpretation you call "GR" was experimentally >> falsified by the laser interferometer experiments ... That experiment >> explicitly showed that the weak equivalence principle ("gravity is just >> geometry") is false. > [Roberts]: Experiments cannot falsify interpretations. The Greenberger-Overhauser experiment showed that gravity is not just geometry because motion of the target body depends on its own mass. I say that means the geometric interpretation is falsified. How do you interpret their result? >> [tvf]: Your only way out of this dilemma in physics is to postulate some >> kind of tangible, material entity in the vacuum or in fields to act as a >> cause and carry momentum. > [Roberts]: No, it apparently is YOUR "only way out". Because YOU are the > one who seems to be constrained by pre-20th century notions of causality > and such. The causality principle: "Every effect has an antecedent, proximate cause." It comes from logic alone, and is a cornerstone of deep-reality physics. Its only possible violation would constitute a miracle, and miracles (while allowed in math) are specifically excluded from physics models. Isaac Newton's comment on this is famous: "That one body may act upon another at a distance through a vacuum, without the mediation of anything else, by and through which their action and force may be conveyed from one to the other, is to me so great an absurdity, that I believe no man who has in philosophical matters a competent faculty of thinking, can ever fall into it." That remains as true today as it was then. How ironic is it that mathematical relativists are today leading the movement to abandon logic? > [Roberts]: what "physical cause" do you think makes light travel in a > straight line? Note you must first provide a "physical" description of a > straight line -- if you fall back on a geometrical description you are > abandoning your own claims. A straight line is the shortest distance between two points. But what has that got to do with claiming that "gravity is just geometry" (geometric GR's now falsified claim) instead of being a 3-space force? Nobody here is claiming that geometry is falsified; only the geometric interpretation of GR is. > [Roberts]: The problem is not with using approximations, the problem is > with your insistence that a specific approximation is the whole theory. It > isn't. So if you accept the validity of "approximations", do you agree that the propagation speed of gravitational force in the 3-space, Euclidean approximation to GR is infinite? (I'm not asking about Newtonian gravitation here. Everyone already knows the speed of gravity is infinite in that model.) >> [tvf]: the absence of propagation delay is the equivalent of setting >> propagation speed to infinity and aberration to zero. > [Roberts]: IN THE APPROXIMATION. The actual equations of GR do not permit > this. You keep confusing the approximation with the theory. DON'T DO THAT! Now who is using words instead of just following the equations? Show me where propagation delay appears in any GR-related equation. > [Roberts]: Carlip showed how it is that the delayed interactions of GR can > APPEAR to be the instantaneous action-at-a-distance of NG. No. He just showed that an instantaneous vector can be decomposed into a retarded vector plus a velocity-dependent correction vector to make gravity look instantaneous, which is trivially true for any vector. But he just made up the velocity-dependent vector. There is no justification for its invention in math or physics, and our paper showed that nature cannot behave that way. > [Roberts]: In GR the interactions are delayed, and in NG they are > instantaneous, yet both accurately model the behavior observed. Therefore > the claim that "gravitational force propagates much faster than c" is > THEORY DEPENDENT, and does not apply to GR. Your claim that "in GR the interactions are delayed" is made up and cannot be justified. Force propagation delay causes aberration which destroys angular momentum conservation. There is no escape from the logical necessity of that, so GR reduces to NG because both use instantaneous force propagation speeds, as Vigier and I showed in our "Foundations" paper. >> [tvf]: what would it take for you to agree that interpreting solutions to >> the GR field equations in terms of classical forces and Euclidean space >> might be a better description of reality than your geometric way of >> interpreting those same equations? > [Roberts]: To do that, you must show that "interpreting solutions to the > GR field equations in terms of classical forces and Euclidean space" is > the same as those field equations. No, I didn't ask if the field equations were better than "the approximation". I asked about the field interpretation with forces in Euclidean space possibly being a better description of reality. Is it possible or impossible to persuade you that might be true? What standard of proof or demonstration must be met to change your mind? -|Tom|- Tom Van Flandern - Sequim, WA - see our web site on frontier astronomy research at http://metaresearch.org
From: Tom Roberts on 8 Sep 2007 10:55 Tom Van Flandern wrote: > Tom Roberts writes: >>> [tvf]: GR has had two different physical interpretations since its >>> inception, but you have been taught only one of them and wish to >>> insist that one is the only one entitled to be called "GR". > >> [Roberts]: I know of both "interpretations", and as I have said >> before, the "forces on a flat background" approach cannot be GR, >> because it cannot describe all the solutions of the field equations of >> GR. I know they are LOCALLY equivalent, but that is not sufficient for >> it to be entitled to be called "GR". > > What makes you the Lord of terminology to declare that what you were > taught is "entitled to be called GR", and what I was taught is not? There is no doubt that the central equation of GR is the Einstein field equation. "What you were taught" does not describe all solutions of the EFE, and hence is not all of GR. > IMO, > you had teachers who didn't know there relativity history or who had an > agenda. And IMHO it is YOU who have the agenda. You seem to want to keep the mantle of GR to deflect criticism. I am aware of the history you elevate beyond its value. >> [Roberts]: spin-two fields on a flat background cannot describe all of >> the solutions of the field equation of GR. > > That is merely a mathematical statement. Equations often contain > possibilities that physics cannot, such as singularities, imaginary > solutions, etc. There are numerous non-singular solutions of the EFE that do not admit a flat 3-space. >> [Roberts]: And, of course, it abandons one of the hallmarks of GR: >> background independence. > > If you mean "aether independence", [...] Please read what I wrote. The idea of "background independence" is well established, and has NOTHING WHATSOEVER to do with any sort of "aether". It is basically the idea that since geometry is dynamic in GR, one cannot assume any particular geometry, one must DETERMINE it in the process of solving the field equation. > once again, you do not know > history. But you do not know the underlying physics of GR. And you are wrong, I do know the history to which you refer. But IMHO Einstein in the 1920's would not qualify as an expert on GR in 2007. We have learned an enormous amount about GR since then. Your method of taking ancient quotes and treating them as gospel IS NOT SCIENCE. >> [Roberts]: Approximations to a theory are OK, as long as one realizes >> they are approximations and their necessary conditions are realized in >> the physical situation. > > I am equally entitled to argue that the force equations are the real > GR because they have been tested by observations; No, you are not, because the "real" GR is the field equation, not any APPROXIMATION to it. > How ironic is it that mathematical relativists are today leading the > movement to abandon logic? What you attempt to call "logic" is really an unbreakable devotion to the past. Yes, modern physics abandons such religious fervor as you display in your quotes of ancient texts. >> [Roberts]: what "physical cause" do you think makes light travel in a >> straight line? Note you must first provide a "physical" description of >> a straight line -- if you fall back on a geometrical description you >> are abandoning your own claims. > > A straight line is the shortest distance between two points. That is a GEOMETRICAL statement, not a "physical cause" in the sense that YOU use the phrase. Since you accept geometry for this, you ought to be able to accept geometry for the rest. Why don't you? >> [Roberts]: The problem is not with using approximations, the problem >> is with your insistence that a specific approximation is the whole >> theory. It isn't. > > So if you accept the validity of "approximations", do you agree that > the propagation speed of gravitational force in the 3-space, Euclidean > approximation to GR is infinite? I agree that in that approximation the "gravitational force" acts as if it were propagated >>c, and is indistinguishable from instantaneous action-at-a-distance. And I also know how that happens in a theory in which no energy, momentum, or information propagates faster than c. > I asked about the field interpretation with forces in > Euclidean space possibly being a better description of reality. Neither you nor I know what "reality" is. All we humans can do is construct models of the world that are increasingly more accurate and cover a wider domain. We observe strong, weak, and electromagnetic interactions, none of which propagate faster than c -- what makes gravity so special? Oh wait -- Coulomb forces ACT AS IF they propagate instantaneously, in a manner directly analogous to your "gravitational force". And we know also that this is due to a specific approximation to the Maxwell's equations, directly analogous to the approximation you make and claim is "the whole GR". Where's the "instantaneous propagation" theory for classical electrodynamics? How does it relate to the observed propagation of EM radiation? -- if "electromagnetic force" is "propagated instantaneously", how is it we actually observe EM radiation to propagate at c? And more topical today: how does this theory relate to QED? (which might give insights how the field interpretation of GR relates to quantum gravity) Tom Roberts
From: eugene_stefanovich on 8 Sep 2007 15:34 On Sep 8, 7:55 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Oh wait -- Coulomb forces ACT AS IF they propagate > instantaneously, in a manner directly analogous to > your "gravitational force". And we know also that this > is due to a specific approximation to the Maxwell's > equations, directly analogous to the approximation > you make and claim is "the whole GR". Where's > the "instantaneous propagation" theory for classical > electrodynamics? How does it relate to the observed > propagation of EM radiation? -- if "electromagnetic > force" is "propagated instantaneously", how is it we > actually observe EM radiation to propagate at c? And > more topical today: how does this theory relate to QED? > (which might give insights how the field interpretation > of GR relates to quantum gravity) You can find answers to some of your questions in http://www.arxiv.org/abs/physics/0504062 .. See, especially, part II of the book. Eugene.
From: Tom Van Flandern on 10 Sep 2007 16:12
Tom Roberts writes: > [Roberts]: I am aware of the history you elevate beyond its value. The history is GR as Einstein invented it. The modern expositions are contrary to Einstein's underlying philosophy. Yet "new age relativists" are constantly donning Einstein's mantle to further their personal agendas. > [Roberts]: IMHO Einstein in the 1920's would not qualify as an expert on > GR in 2007. We have learned an enormous amount about GR since then. Indeed, Einstein would disassociate from GR as taught in 2007. This new age GR violates Einstein's philosophy that led to the original GR, especially by allowing singularities. He complained about using math to guide physics instead of vice versa even in his own time: "Since the mathematicians have invaded the theory of relativity, I do not understand it myself anymore." -- Albert Einstein > [Roberts]: Since you accept geometry for [straight lines], you ought to be > able to accept geometry for the rest. Why don't you? Geometry cannot create 3-space forces. A purely geometric GR would contain no dynamics. > [Roberts]: if "electromagnetic force" is "propagated instantaneously", how > is it we actually observe EM radiation to propagate at c? You correct others for using puns, yet you do it yourself here. Electrodynamic force (e.g., Coulomb force) propagates FTL. Electromagnetic force (e.g., radiation pressure) propagates at speed c. > [Roberts]: [Roberts]: In GR the interactions are delayed, and in NG they > are instantaneous, yet both accurately model the behavior observed. > Therefore the claim that "gravitational force propagates much faster than > c" is THEORY DEPENDENT, and does not apply to GR. This requires redefining "interactions" in some non-physics way. In the field equations, there are no interactions, meaning transfers of momentum from a source mass to a target body causing the target body to accelerate in 3-space. When one converts metric solutions of the field equations into equations of motion in 3-space, the conversion omits aberration instead of including propagation delay, thereby enforcing instantaneous interactions. Saying or even shouting "it isn't so" doesn't change the facts. You cannot apply GR to reality successfully with retarded interactions, except by inventing a magical aberration-cancelling term out of whole cloth the way Carlip does. I'm on travel until next week, which is why I shortened this response to what I thought were points of substance rather than nomenclature. If there are any points you wish to continue discussing, I'll see them and respond ASAP after my return. -|Tom|- Tom Van Flandern - Sequim, WA - see our web site on frontier astronomy research at http://metaresearch.org |