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#191
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Ken S. Tucker wrote on Thu, 24 Apr 2008 04:33:53 -0700:
That rigorous mathematical and physical analysis has been confirmed using a Liouville space extension of mechanics, and also extended to gravity. One obtain basically the same conclusions: the speed of gravity is not c. Needs evidence. You are not reading. I already explained what are the physical and mathematical problems with Low/Carlip analysis of gravitational interactions and how a more *general* and *rigorous* model do *not* support their claims about speed of gravity. My own independent calculations support Low/Carlip's conclusions. In addition to 99.999999% of experiments. But you are not reading. I did not said that GR is implausible. You *misread* me. OK, good. then we're all in agreement. Regards At least you read that part. -- http://canonicalscience.org/en/misce...guidelines.txt |
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On Apr 24, 6:30 am, "Juan R." González-Álvarez
wrote: Ken S. Tucker wrote on Thu, 24 Apr 2008 04:33:53 -0700: That rigorous mathematical and physical analysis has been confirmed using a Liouville space extension of mechanics, and also extended to gravity. One obtain basically the same conclusions: the speed of gravity is not c. Needs evidence. You are not reading. I already explained what are the physical and mathematical problems with Low/Carlip analysis of gravitational interactions and how a more *general* and *rigorous* model do *not* support their claims about speed of gravity. My own independent calculations support Low/Carlip's conclusions. In addition to 99.999999% of experiments. But you are not reading. Oh I have read. At this time, I find a significant FTL physical transmission effect to be theortically and experimentally implausible, I'm NOT saying you are wrong though. I'd be on your and TVF's ban-wagon if I could see any "plausible" reason. I did not said that GR is implausible. You *misread* me. OK, good. then we're all in agreement. Regards At least you read that part. Juan, it's rather judgemental to decide what I've read. I've been engaged in scientific study for nearly 50 years now. Nearly every day, I see a new thing or a different way of seeing an old thing. Regards Ken S. Tucker |
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On Apr 24, 1:16 pm, "Dirk Van de moortel" dirkvandemoor...@ThankS-NO-
SperM.hotmail.com wrote: Ken S. Tucker wrote in message On Apr 24, 6:30 am, "Juan R." González-Álvarez wrote: Ken S. Tucker wrote on Thu, 24 Apr 2008 04:33:53 -0700: That rigorous mathematical and physical analysis has been confirmed using a Liouville space extension of mechanics, and also extended to gravity. One obtain basically the same conclusions: the speed of gravity is not c. Needs evidence. You are not reading. I already explained what are the physical and mathematical problems with Low/Carlip analysis of gravitational interactions and how a more *general* and *rigorous* model do *not* support their claims about speed of gravity. My own independent calculations support Low/Carlip's conclusions. In addition to 99.999999% of experiments. But you are not reading. Oh I have read. At this time, I find a significant FTL physical transmission effect to be theortically and experimentally implausible, I'm NOT saying you are wrong though. I'd be on your and TVF's ban-wagon if I could see any "plausible" reason. I did not said that GR is implausible. You *misread* me. OK, good. then we're all in agreement. Regards At least you read that part. Juan, it's rather judgemental to decide what I've read. I've been engaged in scientific study for nearly 50 years now. So you must be a 70 years old liar then: http://www.flickr.com/photos/dynamics/297774461/ Dirk Vdm I'm young for my age. I build buildings to stay in shape and keep a foot in reality. As a brat, Luckily I was stimulately by Sputnik, and railroads, that was when steam locomotives were still running, wow, choo-choo! So in kindergarten I paint a picture. The teacher comes over and tell's me *my ladders are crooked*. Do you know how difficult it is for a 5 yo to describe to a chick who can't even read a map what a railroad yard looks like if you're on Sputnik taking a picture. My advice, don't even try! Anyway, my point is, in the pix, my scafolding and *my ladder is straight*, so I suppose the chick was right .... part of the time. Regards Ken |
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#195
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[This replies to Mike, Koobee Wublee, and Steve Carlip.]
"Mike" writes: [Mike]: There is nothing in Newton's law, F = dp/dt, that says forces propagate at any speed. To truly understand physics, we must place its laws onto a foundation based on logic. In the discipline known as "deep reality physics", there is only one assumption: "no miracles allowed". The premises that arise from logic alone rather than from experiments or observations or philosophy or mathematics include these: ** Causality: Every effect has an antecedent, proximate cause. ** Creation: No creation ex nihilo; and no demise ad nihil For the reasoning behind these and the other principles of physics, see Ref. [1]. As this applies to your statement, when a force is applied to a target body to change its momentum, that new momentum cannot arise from nothing because that is creation ex nihilo. The momentum must be delivered by the force. That means the force itself must have momentum (the product of mass and velocity), which necessitates that the force propagates. Students often object "What about the force of gravity holding a rock on the ground?" (or some similar example). Even a rock is mostly empty space and can be crushed into a much smaller volume. Gravity forces all its free-to-move entities (such as atomic nuclei or vibrating molecules) to fall. They do so until they collide with a neighbor entity, and they pass along their momentum when they do so. That momentum continues to exist and is passed from entity to entity until it reaches any point of rock-contact with the ground. The ground is held in place by electrostatic forces and sends the received momentum back into the rock, which pushes back on the entities. As long as the force of gravity continues, this cycle of exchanging momentum back and forth continues also, and is responsible for the pressure the rock continually applies to the ground. If there were no gravity to make rock constituents fall, the rock could apply no pressure to another body. Even with gravity, if all rock constituents could be held immobile (say, suspended from above by tiny "strings"), the rock could apply no pressure. It is the (usually unobserved) motion of free rock constituents within the rock that creates any pressure the rock applies and we measure as "weight". The downward pressure caused by gravity exists in every atom of the rock on the ground, and it flattens or reshapes the rock to the extent that it can. Only the back-force from the ground prevents the whole rock from moving downward. So the net force on the rock and its net momentum are both zero. But individual atoms or molecules are continually moving or vibrating to the extent they can within the rock in response to these active forces and the momentum they carry. [Mike]: You keep talking about "speed of gravity" but you never justified why gravity must have a speed in the first place. Gravitation originates in a source mass and affects a target body at some distance. Because action at a distance without intermediaries is a logical impossibility, the force of gravity must propagate from the source mass to the target body and transfer momentum to the latter by contact. [Mike]: action_at_a_distance is sufficient for NM for all practical purposes Yes, but that is a form of miracle because it violates the "proximate" part of the causality principle. As Newton himself said: "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." In other words, it requires a miracle. What is your justification for allowing action at a distance as an explanation for any real, physical process? Do you propose to allow miracles, or can you describe a way (that no one else can) for one body to act on another without something passing between them? Think about it. [Mike]: In GR, there is only motion, induced by curvature of spacetime due to the presence of mass-energy distribution, and vice versa. It is just a clever model. No connection to reality necessarily. This mixes concepts badly. "Motion" in spacetime is nothing like motion in 3-space. So you are using the terms "motion" and/or "spacetime" and or "mass-energy" inappropriately. Indeed, no connection to reality is possible without defining terms in a clear, unambiguous way. That is why I specify "3-space" or "4-space" when I use such terms. One of the objections to the geometric interpretation of GR is that spacetime curvature alone cannot initiate 3-space motion. Only a 3-space force can do that. [Mike]: We do not even know what gravity is. Many of us have had the pleasure of discovering what gravity is physically during the past decade. See 20-author Ref. [2] for the latest research results. In a nutshell, the apple falls from the tree because there is a net graviton wind blowing down toward Earth because Earth blocks part of the graviton wind coming up from below. The fact that this elegant, intuitive picture also gives all the GR effects too is simply a delight. Perhaps you can express why this fundamental understanding of gravity offends your sensibilities so much, especially now that all classical objections have been answered in a satisfactory way. and "Koobee Wublee" writes: [TomVF]: in LR, the transformations operate in only one direction, from the local gravitational potential field to the moving frame. They do not work in reverse. [Wublee]: It is very clear from the following that LR manifests time dilation. ** dt' = dt / sqrt(1 - v^2 / c^2) I don't know how you can argue otherwise. You have taken the meaning of "t" too literally. "t" is really "time" itself in special relativity (SR) because it applies universally. But because there is no reciprocity to the transformations in Lorentzian relativity (LR), "t" in LR means only the reading on clocks in a single frame. Those clocks are slowed by any motion that the frame might have relative to the local gravitational potential field. And this clock-slowing effect is just like the slowing a pendulum clock experiences when the temperature increases: the clock slows, but nothing happens to real time as used to measure change in the universe at large. So in LR, there is no time dilation, only clock-slowing. The clocks in the local gravitational potential field are "standards", and clocks with a relative motion run slow relative to the standards. For example, in the Global Positioning System (GPS), which uses LR clock synchronization, all clocks in all orbits are rate-corrected once after launch to agree with a ground master clock. Ever thereafter, all clocks on the ground and in orbit run at the same average rate. GPS then continues to operate without time dilation. [Wublee]: In your LR equations, there is no mention of gravitational potential. Thus, what you believe in does not really apply to the equations of LR which you have published. SR and LR are about the relativity of motion -- only. GR is about the effect of gravitational potential on clocks. All my papers recognize this difference, and most of them mention both effects on clock rates. The same one-time corrections apply both to clock-slowing from motion and clock-speed-up from orbiting in a weaker gravitational potential. See for example Ref. [3]. [Wublee]: Because of the twin's paradox, SR does not agree with anything. It is utterly absurd of a conjecture. Then you are in the majority of people who have been taught SR but never really understood it. I agree SR is wrong, but only because it was recently falsified by experiment. I sharply disagree that it is absurd. It is an internally consistent model of nature that might have been right. Read my article in Ref. [4], which is designed specifically to explain SR to people who do not understand how it can make sense. It uses a GPS-type rate-corrected clock on board the spacecraft along with a "normal" clock so the traveling twin always knows what time it is back on Earth "right now", to help show how the twin's paradox plays out. [Wublee]: LR does not even degenerate to the Galilean transform at low speeds. It doesn't need to. Think of LR as simply a way of describing what happens to the rate of atomic clocks when immersed in a gravitational potential field, or when moving through one. It doesn't have anything to say about "time" per se. [Wublee]: Yes, the Aether model of GR does seem to explain a great deal. However, in this model, you will find the deflected angle of a photon follows Snell's law. Thus, it is only the Newtonian result not what you are expecting of GR result of twice the Newtonian. Take a look at Eddington's derivation, Ref. [5]. The refraction-in-an-optical-medium model gives double the Newtonian deflection, just as observed. [Wublee]: What you have described does not work for the curvature in spacetime. This is why it was quickly abandoned by the founding fathers of GR which does not include Einstein. Einstein was a nobody. He was a nitwit, a plagiarist, and a liar. Your hostility is misplaced. Einstein eventually accepted aether, accepted that it was represented by the gravitational potential field, decried the geometric interpretation of GR, and wrote a paper showing why "black holes" are impossible. Most of the stuff you hate, attributed to Einstein, is actually due to his followers, especially since 1970, who have run amok with the theory but continue to get published and get funding by claiming they are just testing and verifying "Einstein's theory". The continual usage of "spacetime" with a double meaning, and switching meanings as needed to settle any argument with students, is what you should target. There is only one legitimate physical meaning of "spacetime" in GR, and it has nothing to do with space. In brief, it means proper time multiplied by c to express it in space-like units. See Ref. [6]. The math of GR works very nicely. The physical meaning of that math has become so muddled by post-Einstein relativists that we'll have to bring Einstein back from the dead to get it straightened out. and Steve Carlip writes: [Carlip]: Let R contain a single mass M moving at a constant velocity. ... Then both GR and Newtonian gravity agree that a test mass at p will experience an acceleration toward the "instantaneous" position of M. In particular, the direction of that acceleration will track the motion of M. Correct. The same would be true if M moved with arbitrary acceleration. There was no need for the "constant velocity" assumption except to keep the example simple. As for p, I'm assuming you mean it to be at rest in the selected coordinate system, because moving with M would defeat the purpose of the example. [Carlip]: Now, at time t=0, make the following change in R: stop the motion of M. You apparently agree that this change will have no affect at p until the time for a light signal to reach p from R. Nonsense. What I agreed to was that the gravitational potential field at p would not change until one light-time later than t = 0. However, it is clear from logic, observation, and computer experiments that the force operating at point p changes almost instantly, and any body at point p would cease to accelerate toward mass M almost instantly. Your message fails totally to recognize that field and force are independent physical concepts. These two concepts have a mathematical connection, but one that is ambiguous on the critical point of this discussion: instantaneous or retarded gradient. A scenario very similar to yours and attempting to illustrate the same points is illustrated in a caption and short animation at Ref. [7]. This animation shows how force changes almost instantly, whereas field effects such as light-bending experience light-speed propagation delay. If you really "agree completely with Low's mathematical reasoning," then you accept this direct consequence of that reasoning. No, Low made the same oversight you just did. Field and force are two different things. One is retarded and the other is nearly instantaneous. But the physics is very comfortable with that as long as force shapes field and not vice versa. [Carlip]: Write down the exact solution of the Einstein field equations for a mass M that initially moves at a constant velocity and then abruptly stops. ... Now just compute the acceleration at p. Same issue. More on this below. [Carlip]: This is not a question of an "interpretation" -- it is a direct, unambiguous mathematical prediction. You can only say that because you have apparently not understood the real issue. (More below.) [TomVF]: The one and only mathematical question of importance here to the speed of gravity issue is this: For a target body with a transverse motion relative to the source mass, should we use the retarded gradient or the instantaneous gradient to get the force? [Carlip]: There is no such thing as a "retarded gradient." The gradient of a function is the vector of its spatial derivatives. Time doesn't come into it. Here you make an elementary mistake. It takes two points (or one point and a direction) to determine a vector. So there is most definitely a "time" issue because there is no remote simultaneity in relativity. That means if the two points are synchronized in M's frame, they are not synchronized in p's frame; and vice versa. So the "gradient" cannot be the same for both frames if they have a relative transverse motion. Please reflect on this point because it appears to be the key to understanding why the speed of gravity issue cannot be reduced to semantics or swept under the rug in the way that you suggest. [Carlip]: It is also an elementary mathematical fact, of course, that if a function at x at time t is determined by the behavior of some source at an earlier time t', then the gradient of the function of x at time t is also determined by the behavior of some source at time t'. In accord with the relativity principle, you are not entitled to adopt the source mass frame as special and ignore the view from the target body frame, or vice versa. Because of their relative transverse motion, each frame gets a different direction for the gradient function. [TomVF]: If this force, or "gravitational influences" (your term), propagates from source mass to target body at speed c, then we must use the retarded gradient, which leads to wrong answers (outward spiraling orbits). [Carlip]: You can, in fact, do all of the calculations without ever using a potential. Of course. Potentials are simply a mathematical convenience. The core point is that gravitational force shapes the gravitational potential field (the subject of the field equations), and not vice versa. The latter has light-speed propagation delay, the former does not. Once that distinction is made, the existing equations work. But if you force a light-speed propagation delay onto the force, the equations go badly wrong right away. (Orbits spiral.) However, I'm telling you little if anything you don't already know. Why the resistance to the obvious? Does tradition outweigh logic? -|Tom|- REFERENCES: [1] "Physics has its principles", in "Gravitation, Electromagnetism and Cosmology", K. Rudnicki, ed., C. Roy Keys Inc., Montreal, 87-101 (2001); also at http://metaresearch.org/cosmology/Ph...Principles.asp. [2] "Pushing Gravity: New Perspectives on Le Sage's Theory of Gravitation", M. Edwards, ed., Apeiron Press, Montreal (2002). [3] "Gravitational force vs. gravitational potential", http://www.schriever.af.mil/GPS/PAWG...anflandern.ppt. [4] "What the GPS tells us about the twin's paradox", in "Einstein, Relativity and Absolute Simultaneity" edited by W.L. Craig and Q. Smith, Routledge, London & New York, pp. 212-228 (2008); also at http://metaresearch.org/cosmology/gravity/gps-twins.asp. [5] Sir Arthur Eddington, "Space, Time & Gravitation", Cambridge Univ. Press, first published 1920, reprinted 1987, p. 109. [6] "Does space curve?", http://metaresearch.org/cosmology/gravity/spacetime.asp. [7] "What if the Sun suddenly disappeared?" Read animation #6 caption at http://metaresearch.org/media%20and%...animations.asp, then view animation. Tom Van Flandern - Sequim, WA - see our web site on frontier astronomy research at http://metaresearch.org |
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#196
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On Apr 29, 7:33 pm, "Tom Van Flandern" wrote:
“Koobee Wublee" wrote: [Wublee]: It is very clear from the following that LR manifests time dilation. ** dt' = dt / sqrt(1 - v^2 / c^2) I don't know how you can argue otherwise. You have taken the meaning of "t" too literally. "t" is really "time" itself in special relativity (SR) because it applies universally. But because there is no reciprocity to the transformations in Lorentzian relativity (LR), "t" in LR means only the reading on clocks in a single frame. Those clocks are slowed by any motion that the frame might have relative to the local gravitational potential field. And this clock-slowing effect is just like the slowing a pendulum clock experiences when the temperature increases: the clock slows, but nothing happens to real time as used to measure change in the universe at large. So in LR, there is no time dilation, only clock-slowing. The clocks in the local gravitational potential field are "standards", and clocks with a relative motion run slow relative to the standards. Your LR does not satisfy the principle of relativity. Your clock slowing but no time dilation is spooky. For example, in the Global Positioning System (GPS), which uses LR clock synchronization, all clocks in all orbits are rate-corrected once after launch to agree with a ground master clock. Ever thereafter, all clocks on the ground and in orbit run at the same average rate. GPS then continues to operate without time dilation. GPS continues to function because there is no need for the rate of time flow in the satellites to be the same as on the ground. shrug [Wublee]: In your LR equations, there is no mention of gravitational potential. Thus, what you believe in does not really apply to the equations of LR which you have published. SR and LR are about the relativity of motion -- only. GR is about the effect of gravitational potential on clocks. All my papers recognize this difference, and most of them mention both effects on clock rates. The same one-time corrections apply both to clock-slowing from motion and clock-speed-up from orbiting in a weaker gravitational potential. See for example Ref. [3]. I understand what you are saying. As I said, it is utterly spooky. [Wublee]: Because of the twin's paradox, SR does not agree with anything.. It is utterly absurd of a conjecture. Then you are in the majority of people who have been taught SR but never really understood it. You are very wrong here. Your evaluation of me is just as spooky as your LR and all that clock slowing without any time dilation. You must believe in the dark art of physics as well. Apparently, you have not thought out all the mechanisms that can cause a perfectly working clock to slow down. shrug I agree SR is wrong, but only because it was recently falsified by experiment. The Lorentz transform is wrong right from the very beginning. Because of the combination of time dilation and satisfying the principle of relativity, it manifests relative simultaneity and thus the twin’s paradox. Since SR is merely an interpretation to the Lorentz transform, it is equally invalid as well. It does not take any experiment to prove it wrong. shrug I sharply disagree that it is absurd. That is perhaps you do not understand the twin’s paradox. shrug It is an internally consistent model of nature that might have been right. This is nonsense. SR manifests the twin’s paradox. Read my article in Ref. [4], which is designed specifically to explain SR to people who do not understand how it can make sense. It uses a GPS-type rate-corrected clock on board the spacecraft along with a "normal" clock so the traveling twin always knows what time it is back on Earth "right now", to help show how the twin's paradox plays out. You are very lost. shrug [Wublee]: LR does not even degenerate to the Galilean transform at low speeds. It doesn't need to. Think of LR as simply a way of describing what happens to the rate of atomic clocks when immersed in a gravitational potential field, or when moving through one. It doesn't have anything to say about "time" per se. Your LR contradicts the Galilean transform. Yet, you do not even realize it. This is the basics. You do not know what you are talking about. shrug [Wublee]: Yes, the Aether model of GR does seem to explain a great deal. However, in this model, you will find the deflected angle of a photon follows Snell's law. Thus, it is only the Newtonian result not what you are expecting of GR result of twice the Newtonian. Take a look at Eddington's derivation, Ref. [5]. The refraction-in-an-optical-medium model gives double the Newtonian deflection, just as observed. [Wublee]: What you have described does not work for the curvature in spacetime. This is why it was quickly abandoned by the founding fathers of GR which does not include Einstein. Einstein was a nobody. He was a nitwit, a plagiarist, and a liar. Your hostility is misplaced. What hostility? Einstein being a nitwit, a plagiarist, and a liar is a historic fact. He was nobody. There is no need to hate, to admire, or even to worship that man. shrug Einstein eventually accepted aether, I really do not care what Einstein’s religious belief is. shrug accepted that it was represented by the gravitational potential field, Einstein could think whatever he wanted. He did not derive the Lorentz transform or the field equations. shrug decried the geometric interpretation of GR, and wrote a paper showing why "black holes" are impossible. OK, what is the reason that Einstein thought black holes are not possible? Because he endorsed Schwarzschild’s original solution (no black holes) to the field equations but not Hilbert’s solution now known as the Schwarzschild metric? There are infinite other solutions out there that are all asymptotically flat, spherically symmetric, and static that does or does not manifest black holes. shrug Most of the stuff you hate, attributed to Einstein, is actually due to his followers, especially since 1970, who have run amok with the theory but continue to get published and get funding by claiming they are just testing and verifying "Einstein's theory". On the contrary, despite the nonsense in GR, I truly enjoyed being one of the very few who actually understand how the field equations are derived, and I really do not care very much to your nemesis, Einstein’s followers since 1970. shrug The continual usage of "spacetime" with a double meaning, and switching meanings as needed to settle any argument with students, is what you should target. There is only one legitimate physical meaning of "spacetime" in GR, and it has nothing to do with space. In brief, it means proper time multiplied by c to express it in space-like units. See Ref. [6]. There is no such physical quantity as spacetime. Spacetime is merely a mathematical creation. It is a 4-dimensional expansion to how Riemann described curved space. Spacetime was the creation of the Goettingen group of mathematicians including Hilbert, Klein, Schwarzschild, and Minkowski. The math of GR works very nicely. The physical meaning of that math has become so muddled by post-Einstein relativists that we'll have to bring Einstein back from the dead to get it straightened out. I am very certain you do not even understand how the field and the geodesic equations are derived. shrug I thought you are quite intelligent after correcting professor Carlip’s error on the aberration of gravity, but now I do not think so. However, I do thank your correspondence though. By the way, were you that engineer who showed the physicists that by solving four equations with four unknowns, you can retrieve altitude, latitude, longitude, and time information from four GPS satellites? With four acquisitions instead of original proposal of three, there is no more need to have time flow of the satellites to synchronize with the ground. |
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#197
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On Apr 30, 3:33 am, "Tom Van Flandern" wrote:
[This replies to Mike, Koobee Wublee, and Steve Carlip.] "Mike" writes: [Mike]: There is nothing in Newton's law, F = dp/dt, that says forces propagate at any speed. To truly understand physics, we must place its laws onto a foundation based on logic. In the discipline known as "deep reality physics", there is only one assumption: "no miracles allowed". The premises that arise from logic alone rather than from experiments or observations or philosophy or mathematics include these: ** Causality: Every effect has an antecedent, proximate cause. ** Creation: No creation ex nihilo; and no demise ad nihil For the reasoning behind these and the other principles of physics, see Ref. [1]. As this applies to your statement, when a force is applied to a target body to change its momentum, that new momentum cannot arise from nothing because that is creation ex nihilo. The momentum must be delivered by the force. That means the force itself must have momentum (the product of mass and velocity), which necessitates that the force propagates. Students often object "What about the force of gravity holding a rock on the ground?" (or some similar example). Even a rock is mostly empty space and can be crushed into a much smaller volume. Gravity forces all its free-to-move entities (such as atomic nuclei or vibrating molecules) to fall. They do so until they collide with a neighbor entity, and they pass along their momentum when they do so. That momentum continues to exist and is passed from entity to entity until it reaches any point of rock-contact with the ground. The ground is held in place by electrostatic forces and sends the received momentum back into the rock, which pushes back on the entities. As long as the force of gravity continues, this cycle of exchanging momentum back and forth continues also, and is responsible for the pressure the rock continually applies to the ground. If there were no gravity to make rock constituents fall, the rock could apply no pressure to another body. Even with gravity, if all rock constituents could be held immobile (say, suspended from above by tiny "strings"), the rock could apply no pressure. It is the (usually unobserved) motion of free rock constituents within the rock that creates any pressure the rock applies and we measure as "weight". The downward pressure caused by gravity exists in every atom of the rock on the ground, and it flattens or reshapes the rock to the extent that it can. Only the back-force from the ground prevents the whole rock from moving downward. So the net force on the rock and its net momentum are both zero. But individual atoms or molecules are continually moving or vibrating to the extent they can within the rock in response to these active forces and the momentum they carry. [Mike]: You keep talking about "speed of gravity" but you never justified why gravity must have a speed in the first place. Gravitation originates in a source mass and affects a target body at some distance. Because action at a distance without intermediaries is a logical impossibility, the force of gravity must propagate from the source mass to the target body and transfer momentum to the latter by contact. [Mike]: action_at_a_distance is sufficient for NM for all practical purposes Yes, but that is a form of miracle because it violates the "proximate" part of the causality principle. As Newton himself said: "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." In other words, it requires a miracle. What is your justification for allowing action at a distance as an explanation for any real, physical process? Do you propose to allow miracles, or can you describe a way (that no one else can) for one body to act on another without something passing between them? Think about it. We agree that miracles are not allowed in Nature. But, human minds believe in miracles. Miracle is a relative concept. If you switch on a light bulb, an uneducated neanderthal specimen would exclaim "oh, miracle!", but you know that's not a miracle at all, only a device that follows strict physical laws. Thus, miracles have a lot to do with scientific knowledge. The laws of nature that you 'know' might be insufficient to explain certain kind of phenomena, so you would consider those phenomena as miracles. Suppose now, that you are that uneducated neanderthal with respect to an overly advanced alien, coming to you with an extraordinary device. He switches on that device and you start to levitate. You would exclaim "wow, miracle!", but the alien knows it is not a miracle at all, just natural laws technological application. |
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On Apr 29, 10:33*pm, "Tom Van Flandern"
wrote: "Mike" writes: [Mike]: There is nothing in Newton's law, F = dp/dt, that says forces propagate at any speed. * * To truly understand physics, we must place its laws onto a foundation based on logic. In the discipline known as "deep reality physics", there is only one assumption: "no miracles allowed". The problem is you cannot define miracles apart from laws of physics. If your definition of a miracle is an event that violates the laws of physics then nothing along these lines has been observed so far. I think you define miracle as something that violates your accepted logic. This is not a miracle in a sense that it also violates physical laws. Because the physical alws we have accepted so far are those which are not violated. Thus, you must forst show the conenction fo your system of logic to physical reality. This is what Aristotle called Metaphysics. Causality for example, is not physics but metaphysics. * * The premises that arise from logic alone rather than from experiments or observations or philosophy or mathematics include these: ** Causality: Every effect has an antecedent, proximate cause. ** Creation: No creation ex nihilo; and no demise ad nihil I do not see how these arise from logic, actually from any system of logic. These are postulates, or better a priori axioms. * * For the reasoning behind these and the other principles of physics, see Ref. [1]. * * As this applies to your statement, when a force is applied to a target body to change its momentum, that new momentum cannot arise from nothing because that is creation ex nihilo. The momentum must be delivered by the force. That means the force itself must have momentum (the product of mass and velocity), which necessitates that the force propagates. This is one of the most peculiar and starnge (to say the least) statements I have ever read in usenet. I am sorry to say that. First, you declare force as a feature of reality which is not physics but metaphysics. Then, you say that this feature of reality has the momentum which it delivers. I think you should read Descartes and Leibniz. They extensively dealt with these metaphysical issues. Because the subject is too deep, I warn you: you talk about things that others have extensively reasearched long before and there is a huge body of literature that describes the problems with conclusions contrary to yours. First, to start with, there is no such thing as a "force" as an entity. Nobody has ever seen one. To get a force on a target body, you must have an agent to delever it. That is how the law of action- reaction emerges. For example, to have a force on a rock, you must push it and impart some of your momentum to it. This is Lagrangian Interaction and nothign else. You can forget about forces. All you have is material bodies converting work to kinetic energy. [Mike]: You keep talking about "speed of gravity" but you never justified why gravity must have a speed in the first place. * * Gravitation originates in a source mass and affects a target body at some distance. Because action at a distance without intermediaries is a logical impossibility, the force of gravity must propagate from the source mass to the target body and transfer momentum to the latter by contact. Logical impossibilities may or may not have anything to do with physics. YOu want to say that it violates your axiom of causality. That's all. But that axiom may violate in turn how physical reality works, you do not know that. [Mike]: action_at_a_distance is sufficient for NM for all practical purposes * * Yes, but that is a form of miracle because it violates the "proximate" part of the causality principle. This is mot correct. It is a miracle only if your axiom is accepted as true. It is not a miracle otherwise. Also, what proximate means to you and to your axiom, may be different for physical reality. For instance, in physical reality maybe everything is proximate in some sense. Here you go, your axiom is not necessary. As Newton himself said: "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." Also Newton said: "I likewise call attractions and impulses, in the same sense, accelerative, and motive; and use the words attraction, impulse or propensity of any sort towards a centre, promiscuously, and indifferently, one for another; considering those forces not physically, but mathematically: wherefore, the reader is not to imagine, that by those words, I anywhere take upon me to define the kind, or the manner of any action, the causes or the physical reason thereof, or that I attribute forces, in a true and physical sense, to certain centres (which are only mathematical points); when at any time I happen to speak of centres as attracting, or as endued with attractive powers." * * In other words, it requires a miracle. What is your justification for allowing action at a distance as an explanation for any real, physical process? Do you propose to allow miracles, or can you describe a way (that no one else can) for one body to act on another without something passing between them? Think about it. It is a miracle in your sense. There are many other possibilities in which it may not be a miracle at all. THia ia the reason naive realism fails. [Mike]: In GR, there is only motion, induced by curvature of spacetime due to the presence of mass-energy distribution, and vice versa. It is just a clever model. No connection to reality necessarily. * * This mixes concepts badly. "Motion" in spacetime is nothing like motion in 3-space. So you are using the terms "motion" and/or "spacetime" and or "mass-energy" inappropriately. Indeed, no connection to reality is possible without defining terms in a clear, unambiguous way. That is why I specify "3-space" or "4-space" when I use such terms. * * One of the objections to the geometric interpretation of GR is that spacetime curvature alone cannot initiate 3-space motion. Only a 3-space force can do that. Not, even force cannot initiate motion. Motion is a w-order infinite supertask. When using naivly terms such as "initiate" and "motion" you get into many problems. Motion cannot even start that way. IN GR, by the way, you do not need to "initiate motion" becausse everything is in motion. in GR "eveything is in flux". But when using such metaphysical expressions such as causality and "motion initiation" you will soon get into troubles. [Mike]: We do not even know what gravity is. * * Many of us have had the pleasure of discovering what gravity is physically during the past decade. See 20-author Ref. [2] for the latest research results. In a nutshell, the apple falls from the tree because there is a net graviton wind blowing down toward Earth because Earth blocks part of the graviton wind coming up from below. The fact that this elegant, intuitive picture also gives all the GR effects too is simply a delight. In order for such naive concept to work, the ration u/v, whwre u is the speed of an orbiting body and v the speed of the graviton must be very small to avoid drag due to the graviton wind. This leads to FTL speeds for the graviton. Regardless, the collisions would mean instant evaporation of the earth if such particles were hitting it all the time. At least, no existence of surface water due to heat generation. * * Perhaps you can express why this fundamental understanding of gravity offends your sensibilities so much, especially now that all classical objections have been answered in a satisfactory way. It's not fundamental, it's wrong. Gravity due to graviton material flux means we do not exist. Mike and "Koobee Wublee" writes: [TomVF]: in LR, the transformations operate in only one direction, from the local gravitational potential field to the moving frame. They do not work in reverse. [Wublee]: It is very clear from the following that LR manifests time dilation. *** *dt' = dt / sqrt(1 - v^2 / c^2) *I don't know how you can argue otherwise. * * You have taken the meaning of "t" too literally. "t" is really "time" itself in special relativity (SR) because it applies universally. But because there is no reciprocity to the transformations in Lorentzian relativity (LR), "t" in LR means only the reading on clocks in a single frame. Those clocks are slowed by any motion that the frame might have relative to the local gravitational potential field. And this clock-slowing effect is just like the slowing a pendulum clock experiences when the temperature increases: the clock slows, but nothing happens to real time as used to measure change in the universe at large. So in LR, there is no time dilation, only clock-slowing. The clocks in the local gravitational potential field are "standards", and clocks with a relative motion run slow relative to the standards. * * For example, in the Global Positioning System (GPS), which uses LR clock synchronization, all clocks in all orbits are rate-corrected once after launch to agree with a ground master clock. Ever thereafter, all clocks on the ground and in orbit run at the same average rate. GPS then continues to operate without time dilation. [Wublee]: In your LR equations, there is no mention of gravitational potential. Thus, what you believe in does not really apply to the equations of LR which you have published. * * SR and LR are about the relativity of motion -- only. GR is about the effect of gravitational potential on clocks. All my papers recognize this difference, and most of them mention both effects on clock rates. The same one-time corrections apply both to clock-slowing from motion and clock-speed-up from orbiting in a weaker gravitational potential. See for example Ref. [3]. [Wublee]: Because of the twin's paradox, SR does not agree with anything.. It is utterly absurd of a conjecture. * * Then you are in the majority of people who have been taught SR but never really understood it. I agree SR is wrong, but only because it was recently falsified by experiment. I sharply disagree that it is absurd. It is an internally consistent model of nature that might have been right. Read my article in Ref. [4], which is designed specifically to explain SR to people who do not understand how it can make sense. It uses a GPS-type rate-corrected clock on board the spacecraft along with a "normal" clock so the traveling twin always knows what time it is back on Earth "right now", to help show how the twin's paradox plays out. [Wublee]: LR does not even degenerate to the Galilean transform at low speeds. * * It doesn't need to. Think of LR as simply a way of describing what happens to the rate of atomic clocks when immersed in a gravitational potential field, or when moving through one. It doesn't have anything to say about "time" per se. [Wublee]: Yes, the Aether model of GR does seem to explain a great deal. However, in this model, you will find the deflected angle of a photon follows Snell's law. Thus, it is only the Newtonian result not what you are expecting of GR result of twice the Newtonian. * * Take a look at Eddington's derivation, Ref. [5]. The refraction-in-an-optical-medium model gives double the Newtonian deflection, just as observed. [Wublee]: What you have described does not work for the curvature in spacetime. This is why it was quickly abandoned by the founding fathers of GR which does not include Einstein. Einstein was a nobody. *He was a nitwit, a plagiarist, and a liar. * * Your hostility is misplaced. Einstein eventually accepted aether, accepted that it was represented by the gravitational potential field, decried the geometric interpretation of GR, and wrote a paper showing why "black holes" are impossible. Most of the stuff you hate, attributed to Einstein, is actually due to his followers, especially since 1970, who have run amok with the theory but continue to get published and get funding by claiming they are just testing and verifying "Einstein's theory". * * The continual usage of "spacetime" with a double meaning, and switching meanings as needed to settle any argument with students, is what you should target. There is only one legitimate physical meaning of "spacetime" in GR, and it has nothing to do with space. In brief, it means proper time multiplied by c to express it in space-like units. See Ref. [6]. * * The math of GR works very nicely. The physical meaning of that math has become so muddled by post-Einstein relativists that we'll have to bring Einstein back from the dead to get it straightened out. and Steve Carlip writes: [Carlip]: Let R contain a single mass M moving at a constant velocity. .... Then both GR and Newtonian gravity agree that a test mass at p will experience an acceleration toward the "instantaneous" position of M. In particular, the direction of that acceleration will track the motion of M. * * Correct. The same would be true if M moved with arbitrary acceleration. There was no need for the "constant velocity" assumption except to keep the example simple. As for p, I'm assuming you mean it to be at rest in the selected coordinate system, because moving with M would defeat the purpose of the example. [Carlip]: Now, at time t=0, make the following change in R: stop the motion of M. You apparently agree that this change will have no affect at p until the time for a light signal to reach p from R. * * Nonsense. What I agreed to was that the gravitational potential field at p would not change until one light-time later than t = 0. However, it is clear from logic, observation, and computer experiments that the force operating at point p changes almost instantly, and any body at point p would cease to accelerate toward mass M almost instantly. Your message fails totally to recognize that field and force are independent physical concepts. These two concepts have a mathematical connection, but one that is ambiguous on the critical point of this discussion: instantaneous or retarded gradient. * * A scenario very similar to yours and attempting to illustrate the same points is illustrated in a caption and short animation at Ref. [7]. This animation shows how force changes almost instantly, whereas field effects such as light-bending experience light-speed propagation delay. If you really "agree completely with Low's mathematical reasoning," then you accept this direct consequence of that reasoning. * * No, Low made the same oversight you just did. Field and force are two different things. One is retarded and the other is nearly instantaneous. But the physics is very comfortable with that as long as force shapes field and not vice versa. [Carlip]: Write down the exact solution of the Einstein field equations for a mass M that initially moves at a constant velocity and then abruptly stops. ... Now just compute the acceleration at p. * * Same issue. More on this below. [Carlip]: This is not a question of an "interpretation" -- it is a direct, unambiguous mathematical prediction. * * You can only say that because you have apparently not understood the real issue. (More below.) [TomVF]: The one and only mathematical question of importance here to the speed of gravity issue is this: For a target body with a transverse motion relative to the source mass, should we use the retarded gradient or the instantaneous gradient to get the force? [Carlip]: There is no such thing as a "retarded gradient." The gradient of a function is the vector of its spatial derivatives. Time doesn't come into it. * * Here you make an elementary mistake. It takes two points (or one point and a direction) to determine a vector. So there is most definitely a "time" issue because there is no remote simultaneity in relativity. That means if the two points are synchronized in M's frame, they are not synchronized in p's frame; and vice versa. So the "gradient" cannot be the same for both frames if they have a relative transverse motion. * * Please reflect on this point because it appears to be the key to understanding why the speed of gravity issue cannot be reduced to semantics or swept under the rug in the way that you suggest. [Carlip]: It is also an elementary mathematical fact, of course, that if a function at x at time t is determined by the behavior of some source at an earlier time t', then the gradient of the function of x at time t is also determined by the behavior of some source at time t'. * * In accord with the relativity principle, you are not entitled to adopt the source mass frame as special and ignore the view from the target body frame, or vice versa. Because of their relative transverse motion, each frame gets a different direction for the gradient function. [TomVF]: If this force, or "gravitational influences" (your term), propagates from source mass to target body at speed c, then we must use the retarded gradient, which leads to wrong answers (outward spiraling orbits). [Carlip]: You can, in fact, do all of the calculations without ever using a potential. * * Of course. Potentials are simply a mathematical convenience. The core point is that gravitational force shapes the gravitational potential field (the subject of the field equations), and not vice versa. The latter has light-speed propagation delay, the former does not. * * Once that distinction is made, the existing equations work. But if you force a light-speed propagation delay onto the force, the equations go badly wrong right away. (Orbits spiral.) * * However, I'm telling you little if anything you don't already know.. Why the resistance to the obvious? Does tradition outweigh logic? -|Tom|- REFERENCES: [1] "Physics has its principles", in "Gravitation, Electromagnetism and Cosmology", K. Rudnicki, ed., C. Roy Keys Inc., Montreal, 87-101 (2001); also athttp://metaresearch.org/cosmology/PhysicsHasItsPrinciples.asp. [2] "Pushing Gravity: New Perspectives on Le Sage's Theory of Gravitation", M. Edwards, ed., Apeiron Press, Montreal (2002). [3] "Gravitational force vs. gravitational potential",http://www.schriever..af.mil/GPS/PAW...anflandern.ppt. [4] "What the GPS tells us about the twin's paradox", in "Einstein, Relativity and Absolute Simultaneity" edited by W.L. Craig and Q. Smith, Routledge, London & New York, pp. 212-228 (2008); also athttp://metaresearch.org/cosmology/gravity/gps-twins.asp. [5] Sir Arthur Eddington, "Space, Time & Gravitation", Cambridge Univ. Press, first published 1920, reprinted 1987, p. 109. [6] "Does space curve?",http://metaresearch.org/cosmology/gravity/spacetime.asp. [7] "What if the Sun suddenly disappeared?" Read animation #6 caption athttp://metaresearch.org/media%20and%20links/animations/animations.asp, then view animation. Tom Van Flandern - Sequim, WA - see our web site on frontier astronomy research athttp://metaresearch.org |
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On Apr 30, 7:34*pm, Mike wrote:
On Apr 29, 10:33*pm, "TomVanFlandern" wrote: "Mike" writes: [Mike]: There is nothing in Newton's law, F = dp/dt, that says forces propagate at any speed. * * To truly understand physics, we must place its laws onto a foundation based on logic. In the discipline known as "deep reality physics", there is only one assumption: "no miracles allowed". The problem is you cannot define miracles apart from laws of physics. If your definition of a miracle is an event that violates the laws of physics then nothing along these lines has been observed so far. I think you define miracle as something that violates your accepted logic. This is not a miracle in a sense that it also violates physical laws. Because the physical alws we have accepted so far are those which are not violated. Thus, you must forst show the conenction fo your system of logic to physical reality. This is what Aristotle called Metaphysics. Causality for example, is not physics but metaphysics. There is nothing metaphysical about tying causality to material contact, which I believe is Tom VFd's approach. Vern |
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On May 2, 8:19*am, Vern wrote: On Apr 30, 7:34*pm, Mike wrote: On Apr 29, 10:33*pm, "TomVanFlandern" wrote: "Mike" writes: [Mike]: There is nothing in Newton's law, F = dp/dt, that says forces propagate at any speed. * * To truly understand physics, we must place its laws onto a foundation based on logic. In the discipline known as "deep reality physics", there is only one assumption: "no miracles allowed". The problem is you cannot define miracles apart from laws of physics. If your definition of a miracle is an event that violates the laws of physics then nothing along these lines has been observed so far. I think you define miracle as something that violates your accepted logic. This is not a miracle in a sense that it also violates physical laws. Because the physical alws we have accepted so far are those which are not violated. Thus, you must forst show the con |