Debunking Nimtz
in [Relativity]
|
Prev: GETTING RID OF EINSTEIN RELATIVITY
Next: USM
From: Tom Roberts on 29 Sep 2007 12:16 Tom Van Flandern wrote: > Tom Roberts writes: >> Today, science recognizes the fact that we humans are inherently >> limited in what we can do mentally, and ALL we can think about related >> to the real world are MODELS of that world. Science is the process of >> creating and evaluating such models. > > You contradict yourself. First, you said there is no necessity to > "create" 3-space forces. Then when I replied that physicists attempt to > describe reality with *models* involving real, tangible, material > entities, usually in the form of particles and waves, with interactions > by momentum transfers ("forces") through contact, you reply that I am > ignorant of science because science is the process of creating and > evaluating models. That is not my argument, and a perusal of this thread will show how distorted your response here is. > This makes no sense at all unless you are defining "models" as > mathematical models and excluding physics models. No. Re-read what I wrote. There are certain limitations on models imposed by the irreducible relationship between humans and the world we inhabit. One of those is that coordinates are abstract human constructs and no natural process in the world we inhabit uses coordinates in any way. This directly implies that any quantity that depends on coordinates cannot possibly correspond to any physical phenomenon. In GR, your "3-space forces" are in that class of quantities that cannot possibly correspond to any physical phenomenon or process. Now you can abandon GR and make up some other theory in which there is an underlying 3-space relative to which such "forces" are not coordinate dependent. Or you can make an APPROXIMATION to GR in which the coordinates you select are an inherent aspect. But neither of those is GR. > In the meantime, most of us continue to increase our understanding > of, and ability to predict, the natural world through physical models. Sure. But those who actually understand modern physics do not follow your approach. In post-GR physics, the underlying "3-space" you require is considered unreasonable by virtually all physicists (at least those who think about such things). And the fact that it works for computations is well understood via the obvious APPROXIMATION to GR that it represents. >>> [TVF]: As this applies here, in ordinary physics, a body at rest in >>> 3-space cannot begin moving unless a force acts on it. Once it does >>> begin moving, it has acquired new 3-space momentum. The time rate of >>> change of its momentum is the measure of the applied force. ... >>> relativists ... should not be proposing ... the logical equivalent of >>> a miracle. > >> [Roberts]: You merely display your ignorance of GR and its geometry. >> When projected onto your 3-space, using the Newtonian coordinates you >> insist on, the connection is the same as the "force" you require. This >> is not "a miracle", this is just the basic geometry of spaceTIME >> applied to this physical situation and these particular coordinates. > > An effect without a cause is a miracle almost by definition. When you attempt to apply your ancient vocabulary to GR there are problems. This naive use of "cause" is not applicable to MODELS. Indeed, no fundamental theory of physics today includes such a "cause" -- there are CORRELATIONS between quantities, represented by the equations of motion in each such theory, but no "cause". The "causality" you refer to is an emergent property in the large, and not any aspect of the underlying fundamental theory. Indeed, this is an aspect of ANY theory expressed as differential equations. E.g. in Maxwell's equations (not a fundamental theory), charge does not "cause" the fields. The M.E. simply express a CORRELATION between charge and field. In _EXACTLY_ the same way that confuses you about gravity, one cannot claim that the charge over there "causes" this one to move; all one can say is that the requirement that the M.E. be satisfied describes the motion. IOW: you are adding a philosophical baggage ("causes") to a theory that does not actually have that baggage. The concept "cause" is quite similar to the concept "inertia" in this regard: people have rather vague notions of what they are, but there is no quantity in ANY equation of physics one can point to and say "there it is". These concepts are not crisp enough to actually be part of any model or theory. > Your > space-time geometry likewise cannot initiate 3-space motion unless a > 3-space force acts. I repeat: if you INSIST on applying such words, then your "3-space force" corresponds to certain components of the connection projected onto the coordinates you INSIST on using. This is mathematically the same as your "3-space force", but is merely an aspect of the geometry of spaceTIME. And as it is manifestly coordinate dependent, it does not correspond to any actual physical phenomenon. IOW: you consider your "3-space" to be an inherent aspect of nature. The rest of us know that such a COORDINATE-DEPENDENT quantity cannot correspond to any physical phenomenon. > Your "projection" involves a particle moving along a > straight line in 4-space (changing only its time coordinate) until it is > released. Once released, there is no *cause* for the particle to > initiate motion in 3-space. Sure there is! Once released the particle must follow the geodesic path through spaceTIME that corresponds to its conditions when released (before release the force that is holding it prevents it from following such a geodesic). BTW your claim about "straight line in 4-space" is completely wrong -- before release there is nothing "straight" about its trajectory through spaceTIME -- it is accelerated. Your claim here shows how deeply your notions of "3-space" pervade your thinking, and you have no ability to actually consider what is happening in spaceTIME. This is a straight line in your 3-space, but not in spaceTIME. YOU are the one who insists on some mysterious "cause". The rest of us are content to have a model which accurately models the behavior of such a particle. In YOUR VOCABULARY this is a "cause", even though that word is not used for this in GR. > The gravitational potential field has no > moving parts, and slopes alone cannot cause motion to begin unless an > external force acts to initiate it. You attempt to intermix YOUR "3-space" concepts with GR. No wonder you get word salad. In GR, the geometry of spacetime has geodesic paths, and any free particle will follow the geodesic path corresponding to its initial conditions. These geodesic paths are determined by the geometry of spaceTIME, which is commonly called "gravity". > This was said succinctly by Vern, and you ignore the point each time > it is raised, There _IS_ no "point". There is only confusion over terminology. > Here is his point again: "In my > opinion, you [Tom Roberts] have never satisfactorily answered [tvf's] > claim that in the geometric interpretation a straight line may be a > curve, but there is no reason for an object to follow that curve unless > it is already moving." A free particle follows the geodesic path at time t corresponding to its 4-velocity at time t-e (where e is an infinitesimal time interval). If (near the surface of the earth) you hold the particle up, the force of your hand prevents it from following any geodesic path, and the path it actually follows is at constant distance from the surface (this path has nonzero 4-acceleration, but zero 3-acceleration in YOUR "3-space"). When you release the particle, your hand no longer applies a force to the particle, and it follows the geodesic path determined by its 4-velocity at the instant of release, which in this case falls to earth. The "reason" for this is simply the requirement that the Einstein field equation be obeyed. But that is YOUR terminology, not that of GR. Note I used a "3-space" at rest relative to the surface of the earth. How do YOU resolve that with a "3-space" useful for cosmological analyses? In GR this is no problem because the different "3-spaces" are merely different projections of spaceTIME. But you seem to claim "3-space" is an aspect of nature, and I don't see how different "3-spaces" (ones moving with respect to each other) can simultaneously be that.... >>>> [Roberts]: my main disagreement with Van Flandern is his CLAIM to be >>>> using GR, when he manifestly is not doing so. And I also disagree >>>> with his claims of propagation >>c that he thinks are general, but >>>> are actually theory specific and do not apply to GR. > >>> [TVF]: Without meaning to put words in your mouth, I read this as >>> saying that you accept that the field interpretation (or something >>> like it) does validly have 3-space forces, makes testable predictions >>> in Euclidean space, and has passed those tests; and that the >>> "gravitational forces" in that theory do indeed propagate FTL. You >>> disagree only that it is GR. Is that a fair and accurate summary of >>> what you just said? If the answer is "yes", I think we're done. The >>> rest is just nomenclature. What you use is not any sort of "interpretation" of GR, it is an APPROXIMATION. Yes, in that APPROXIMATION the quantity you call "3-space force of gravity" does propagate FTL. Yes, that APPROXIMATION makes predictions in good agreement with experiment and observation. But that APPROXIMATION is not GR itself. And the coordinates used in that APPROXIMATION are essential, so the "3-space force" cannot correspond to any physical phenomenon -- THAT is at base why this approach is not used by physicists. [This is clearly going nowhere. Don't expect me to respond.] Tom Roberts
From: Vern on 2 Oct 2007 03:19 On Sep 29, 12:16 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: <snip> > What you use is not any sort of "interpretation" of GR, it is an > APPROXIMATION. Yes, in that APPROXIMATION the quantity you call "3-space > force of gravity" does propagate FTL. Yes, that APPROXIMATION makes > predictions in good agreement with experiment and observation. But that > APPROXIMATION is not GR itself. And the coordinates used in that > APPROXIMATION are essential, so the "3-space force" cannot correspond to > any physical phenomenon -- THAT is at base why this approach is not used > by physicists. Do you acknowledge that there is a field interpretaion of GR? If so, in that field interpretation, is the force of gravity from one object affecting another object considered close to instantaneous, e.g. ftl and no aberration? Also, if so, in that interpretation, isn't it assumed that the field represents some form of a medium since otherwise no field would exist? Vern
From: Tom Roberts on 2 Oct 2007 11:10 Vern wrote: > On Sep 29, 12:16 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: >> What you use is not any sort of "interpretation" of GR, it is an >> APPROXIMATION. Yes, in that APPROXIMATION the quantity you call "3-space >> force of gravity" does propagate FTL. Yes, that APPROXIMATION makes >> predictions in good agreement with experiment and observation. But that >> APPROXIMATION is not GR itself. And the coordinates used in that >> APPROXIMATION are essential, so the "3-space force" cannot correspond to >> any physical phenomenon -- THAT is at base why this approach is not used >> by physicists. > > Do you acknowledge that there is a field interpretaion of GR? Read what I wrote. This is an APPROXIMATION, not an "interpretation". If it were truly an interpretation of GR, it would apply to all solutions to the EFE, but it doesn't (it applies only to those that admit a flat 3-space as a spacelike submanifold). As an approximation it makes good sense: in GR one can always find a LOCAL flat 3-space in a limited region of the manifold, and once one selects such a foliation of spacetime the equations of the approximation are quite accurate within that region. But as I pointed out earlier, to apply this near the surface of the earth requires a DIFFERENT foliation than to apply it to the solar system, or to apply it to cosmological problems. The "interpretation" has no method to handle these different foliations (there can be just ONE "3-space" if it is a "physical" component of the model), but the approximation inherently accommodates them. Tom Roberts
From: Tom Van Flandern on 5 Oct 2007 21:54 Tom Roberts writes: >> tvf]: This makes no sense at all unless you are defining "models" as >> mathematical models and excluding physics models. > [Roberts]: There are certain limitations on models imposed by the > irreducible relationship between humans and the world we inhabit. One of > those is that coordinates are abstract human constructs and no natural > process in the world we inhabit uses coordinates in any way. This directly > implies that any quantity that depends on coordinates cannot possibly > correspond to any physical phenomenon. However, coordinates are part of "models" only in mathematics. In physics, models involve particles, waves, contacts, forces, momentum, measurements, mass, energy, speed, cause and effect. Coordinates are not a component of physical models, but are merely an aid to measurements of these physical entities. > [Roberts]: In GR, your "3-space forces" are in that class of quantities > that cannot possibly correspond to any physical phenomenon or process. In GR as taught in celestial mechanics, orbits are computed in Euclidean space because observations are made in Euclidean space; and there is no advantage to be gained from using anything more complicated. A 3-space "force" is the time rate of change of (3-space) momentum, and orbiting bodies are obviously changing their momentum, so a physical force is acting by definition. The observations are measures of reality and the theory is a model of that reality. So celestial mechanics includes all of GR that is necessary and sufficient to describe and predict reality. If your GR cannot model reality with equal ease, it is useless for science, even if useful for absorbing grant funds and promoting careers. >> [tvf]: In the meantime, most of us continue to increase our understanding >> of, and ability to predict, the natural world through physical models. > [Roberts]: But those who actually understand modern physics do not follow > your approach. In post-GR physics, the underlying "3-space" you require is > considered unreasonable by virtually all physicists (at least those who > think about such things). Ironically, Einstein, Dirac, and Feynman all favored just such an approach as I described, as do many of the students of these great physicists. Einstein famously complained that "since the mathematicians have invaded the theory of relativity, I do not understand it myself anymore." But I suppose you were also taught that, if you stuck with the party line among geometric relativists, 72 virgins (or some equivalent award) will be awaiting you. I do understand why that has considerable appeal for some. OTOH, if we were to stick to science, you would be required to say WHY using logic with cause and effect to model and predict reality is considered "unreasonable" in the crowd you hang out with. I would truly like to see your effort to defend THAT. >> [tvf]: An effect without a cause is a miracle almost by definition. > [Roberts]: When you attempt to apply your ancient vocabulary to GR there > are problems. This naive use of "cause" is not applicable to MODELS. I agree it is not applicable to mathematical models, which differ from physical models because math models rarely contain constraints and do not respect the logical prohibition against using concepts that are physically impossible. Examples of the latter are singularities, creation ex nihilo, and effects without causes. However, my "na�ve sense of cause" certainly and unquestionably is applicable to physical models with particles, waves, forces, momentum, contact, etc. Geometric relativists and the Copenhagen school in QM are content with mathematical descriptions of nature because they are frustrated by the impossibility of describing reality with physical models consistent with their beliefs, which include many impossible things. In the meantime, those of us following the field interpretation of GR have had outstanding successes at describing the WHY of physical phenomena, cause and effect, what gravity really is, resolving paradoxes that exist only in your world, etc. The essence of this difference about how to do physics is goals. The goal of the geometric relativists is describing nature because they have given up on physical models of nature. The goal of the deep reality physicist is the ability to predict new phenomena. That requires a fundamental understanding of causes and effects and how they interact. Only then can we derive appropriate equations to aid calculation of new phenomena, always remembering the limitations of those equations. For example, Einstein considered the presence of singularities in his field equations, and rejected them as artifacts of incomplete equations. See A. Einstein, "Annals of Mathematics", vol. 40, #4, pp. 922-936, 1939. The concluding paragraph reads: "This investigation arose out of discussions [with Robertson and Bargmann] on the mathematical and physical significance of the Schwarzschild singularity. The problem quite naturally leads to the question, answered by this paper in the negative, as to whether physical models are capable of exhibiting such a singularity." Please note the importance Einstein places on "physical models". > [Roberts]: Indeed, no fundamental theory of physics today includes such a > "cause" ... My imagination must be working overtime because I can distinctly recall having read several such models with detailed physical cause and effect, some so simple they meet Einstein's criterion: "You do not really understand something unless you can explain it to your grandmother." > [Roberts]: E.g. in Maxwell's equations (not a fundamental theory), charge > does not "cause" the fields. ... In _EXACTLY_ the same way that confuses > you about gravity, one cannot claim that the charge over there "causes" > this one to move; all one can say is that the requirement that the M.E. be > satisfied describes the motion. Of course charge and gravity do not cause fields. But the E-M force and the gravitational force do shape the fields and make them denser near masses. I'm speaking here of physical theories in which forces are momentum exchanges between particles or waves that collide, and fields are mediums of such entities and are shaped by forces. > [Roberts]: IOW: you are adding a philosophical baggage ("causes") to a > theory that does not actually have that baggage. The concept "cause" is > quite similar to the concept "inertia" in this regard: people have rather > vague notions of what they are, but there is no quantity in ANY equation > of physics one can point to and say "there it is". These concepts are not > crisp enough to actually be part of any model or theory. Well, we pack energy bars instead of bricks in our baggage. Inertia is now a crisp and well-understood phenomenon in deep reality physics -- again, at the level your grandmother can understand. I had dinner recently with a physicist and his wife. His professional expertise was inertia. With no visual aids, in five minutes I was able to explain the nature of inertia to her so clearly that she understood it at a fundamental level for the first time. In language somewhat more appropriate for a physics audience, a similar explanation can be found at http://metaresearch.org/cosmology/gravity/Does%20Gravity%20Have%20Inertia.asp. This explanation is part of the Meta Model, one of the five modern theories of cosmology still on the table for discussion -- especially by those convinced by the observational evidence that the Big Bang is not responding to CPR. >> [tvf]: Your space-time geometry likewise cannot initiate 3-space motion >> unless a 3-space force acts. > [Roberts]: ... This is mathematically the same as your "3-space force", > but is merely an aspect of the geometry of spaceTIME. My word "initiate" is equivalent to "cause". Your geometric GR has no cause and effect, it is merely a description. The cause of motion commencing in field GR is classical gravitons striking a target body and transferring the gravitons' momentum to the body. > [Roberts]: IOW: you consider your "3-space" to be an inherent aspect of > nature. The rest of us know that such a COORDINATE-DEPENDENT quantity > cannot correspond to any physical phenomenon. Where do you see any mention of coordinates in these physical models? One can describe phenomena in any coordinate system, but the barycentric inertial frame is normally the simplest. Your confusion here stems from geometric GR's assumption that "space" is something that can be curved or manipulated by matter. In deep reality physics, only material mediums can be operated on by other material substances. The terms "space", "time", and "mass" are reserved for the dimensions of physics, the units in terms of which everything else is measured. There is therefore only one space by definition, and it is normally Euclidean by construction. That is all we need to make predictions and compare them with measurements of reality. Anything more than is required by observations, experiments, or logic is fantasy or science fiction. Added dimensions are examples. They are required only by mathematical models that have arrived at paradoxes or contradictions. The productive approach is to scrap the mathematical model and go back to the physics to see how the equations need to be changed. >> [tvf]: Your "projection" involves a particle moving along a straight line >> in 4-space (changing only its time coordinate) until it is released. Once >> released, there is no *cause* for the particle to initiate motion in >> 3-space. > [Roberts]: Sure there is! Once released the particle must follow the > geodesic path through spaceTIME that corresponds to its conditions when > released (before release the force that is holding it prevents it from > following such a geodesic). That is just another mathematical description without a cause. Causes in physics involve contacts because a cause without contact is action at a distance, a form of miracle. The important point is that geometry alone cannot *cause* (initiate) motion. And we haven't even touched on the implicit contradiction in your usage of the word "spaceTIME" in this context. Can you think of a definition of that term consistent with such a usage? Spacetime is not a physical entity that can have "paths through it" the way space can. But you already know of the hazard of confusion spacetime with space, as MTW warned about on p. 32 of "Gravitation" (1971). > [Roberts]: BTW your claim about "straight line in 4-space" is completely > wrong -- before release there is nothing "straight" about its trajectory > through spaceTIME -- it is accelerated. Your claim here shows how deeply > your notions of "3-space" pervade your thinking, and you have no ability > to actually consider what is happening in spaceTIME. This is a straight > line in your 3-space, but not in spaceTIME. I'll have to challenge you on that claim. The "fixed" body may indeed be "accelerated" by geometric GR's quaint redefinition of the word "accelerated", but its 4-space path is nonetheless a straight line in a Minkowski diagram, and the rate of passage of proper time is uniform. That covers both usages of "spaceTIME". Likewise, a geodesic path may be "unaccelerated" in geometric GR, but its path is not a straight line in anyone's imagination. For example, stars seen near the Sun are displaced, showing that their paths through space are bent. How do you propose to straighten them out in spacetime? > [Roberts]: The "reason" for this is simply the requirement that the > Einstein field equation be obeyed. But that is YOUR terminology, not that > of GR. Equations are not causes. A cause is whatever happens to the target body that makes it obey the Einstein field equation. (BTW, the field equations do not describe any kind of motion. That requires equations of motion. The latter equations follow from the field equations once a few additional assumptions are added. Examples are instantaneous interactions, and field gradients producing forces.) >>>> [TVF]: Without meaning to put words in your mouth, I read this as >>>> saying that you accept that the field interpretation (or something like >>>> it) does validly have 3-space forces, makes testable predictions in >>>> Euclidean space, and has passed those tests; and that the >>>> "gravitational forces" in that theory do indeed propagate FTL. You >>>> disagree only that it is GR. Is that a fair and accurate summary of >>>> what you just said? If the answer is "yes", I think we're done. The >>>> rest is just nomenclature. > [Roberts]: What you use is not any sort of "interpretation" of GR, it is > an APPROXIMATION. Yes, in that APPROXIMATION the quantity you call > "3-space force of gravity" does propagate FTL. Yes, that APPROXIMATION > makes predictions in good agreement with experiment and observation. But > that APPROXIMATION is not GR itself. And the coordinates used in that > APPROXIMATION are essential, so the "3-space force" cannot correspond to > any physical phenomenon -- THAT is at base why this approach is not used > by physicists. I take that as a "yes". > [Roberts]: [This is clearly going nowhere. Don't expect me to respond.] It's your life and your career. But it's everyone's loss if you waste it. Use your brilliant mind to see past the peer pressure you experience daily. Ask questions of the embarrassing variety. Don't accept smokescreens for answers. Logic trumps authority. Intimidation is a weapon, not a tool. Make a difference. -|Tom|- Tom Van Flandern - Sequim, WA - see our web site on frontier astronomy research at http://metaresearch.org
From: Pentcho Valev on 6 Oct 2007 02:03
On 6 Oct, 04:54, "Tom Van Flandern" <to...(a)metaresearch.org> wrote: > Tom Roberts writes: > >> tvf]: This makes no sense at all unless you are defining "models" as > >> mathematical models and excluding physics models. > > [Roberts]: There are certain limitations on models imposed by the > > irreducible relationship between humans and the world we inhabit. One of > > those is that coordinates are abstract human constructs and no natural > > process in the world we inhabit uses coordinates in any way. This directly > > implies that any quantity that depends on coordinates cannot possibly > > correspond to any physical phenomenon. > > However, coordinates are part of "models" only in mathematics. In > physics, models involve particles, waves, contacts, forces, momentum, > measurements, mass, energy, speed, cause and effect. Coordinates are not a > component of physical models, but are merely an aid to measurements of these > physical entities. > > > [Roberts]: In GR, your "3-space forces" are in that class of quantities > > that cannot possibly correspond to any physical phenomenon or process. > > In GR as taught in celestial mechanics, orbits are computed in Euclidean > space because observations are made in Euclidean space; and there is no > advantage to be gained from using anything more complicated. > > A 3-space "force" is the time rate of change of (3-space) momentum, and > orbiting bodies are obviously changing their momentum, so a physical force > is acting by definition. > > The observations are measures of reality and the theory is a model of > that reality. So celestial mechanics includes all of GR that is necessary > and sufficient to describe and predict reality. If your GR cannot model > reality with equal ease, it is useless for science, even if useful for > absorbing grant funds and promoting careers. > > >> [tvf]: In the meantime, most of us continue to increase our understanding > >> of, and ability to predict, the natural world through physical models. > > [Roberts]: But those who actually understand modern physics do not follow > > your approach. In post-GR physics, the underlying "3-space" you require is > > considered unreasonable by virtually all physicists (at least those who > > think about such things). > > Ironically, Einstein, Dirac, and Feynman all favored just such an > approach as I described, as do many of the students of these great > physicists. Einstein famously complained that "since the mathematicians have > invaded the theory of relativity, I do not understand it myself anymore." > > But I suppose you were also taught that, if you stuck with the party > line among geometric relativists, 72 virgins (or some equivalent award) will > be awaiting you. I do understand why that has considerable appeal for some. > > OTOH, if we were to stick to science, you would be required to say WHY > using logic with cause and effect to model and predict reality is considered > "unreasonable" in the crowd you hang out with. I would truly like to see > your effort to defend THAT. > > >> [tvf]: An effect without a cause is a miracle almost by definition. > > [Roberts]: When you attempt to apply your ancient vocabulary to GR there > > are problems. This naive use of "cause" is not applicable to MODELS. > > I agree it is not applicable to mathematical models, which differ from > physical models because math models rarely contain constraints and do not > respect the logical prohibition against using concepts that are physically > impossible. Examples of the latter are singularities, creation ex nihilo, > and effects without causes. > > However, my "naïve sense of cause" certainly and unquestionably is > applicable to physical models with particles, waves, forces, momentum, > contact, etc. Have you ever tried to explain the negative result of the Michelson- Morley experiment in terms of Newton's particle model of light? You could have come to this conclusion: http://philsci-archive.pitt.edu/archive/00001743/02/Norton.pdf John Norton: "Einstein regarded the Michelson-Morley experiment as evidence for the principle of relativity, whereas later writers almost universally use it as support for the light postulate of special relativity......THE MICHELSON-MORLEY EXPERIMENT IS FULLY COMPATIBLE WITH AN EMISSION THEORY OF LIGHT THAT CONTRADICTS THE LIGHT POSTULATE." Pentcho Valev |