Is Length Contraction in SR physical??
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From: kenseto on 11 Feb 2010 18:37 On Feb 11, 10:32 am, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 11, 9:07 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > On Feb 10, 8:49 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Feb 10, 4:57 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > On Feb 10, 9:39 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Feb 10, 8:06 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > On Feb 9, 5:56 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > On Feb 9, 4:29 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > On Feb 9, 11:32 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > > On Feb 8, 2:58 pm, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > > > On Feb 8, 3:25 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > > > > > > > On Feb 7, 8:39 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > > > > > > When Ken started asking these questions 15 years ago, they were > > > > > > > > > > > > > reasonable questions. When after a couple of years it was clear he was > > > > > > > > > > > > > not listening to the answers given to his questions, the tone of the > > > > > > > > > > > > > responses became a little different. > > > > > > > > > > > > > Why should I listen to what you said when you did made sense.?? > > > > > > > > > > > > Ken, it isn't wise to stop listening to people if you do not > > > > > > > > > > > understand what they are saying. It would be important in that case to > > > > > > > > > > > say, "I don't understand what you are saying. Can you explain it > > > > > > > > > > > differently so I can understand it?" > > > > > > > > > > > I don't listen to you because you keep on making contradictory claims. > > > > > > > > > > For example the pole is physically contracted to fit the barn and at > > > > > > > > > > the same time the pole does not fit into the barn because it is not > > > > > > > > > > physically contracted. > > > > > > > > > > Those are not contradictory claims. > > > > > > > > > Yes they are. > > > > > > > > > >Those are different accounts made > > > > > > > > > in different reference frames. There is no requirement that the > > > > > > > > > accounts be identical in different reference frames, and therefore > > > > > > > > > they are not contradictory. > > > > > > > > > They have to agree whether the physical length of the pole can fit > > > > > > > > into the shorter barn. > > > > > > > > No, they do not. There is no such requirement. > > > > > > > There is the requirement that if you claim physical contraction then > > > > > > the pole is really contracted > > > > > > I have no idea what you mean by "really contracted". It is physically > > > > > contracted in one frame because it actually fits between the doors > > > > > when the doors are closed. How can that be called anything other than > > > > > physical? It does NOT mean *materially* contracted though -- as in > > > > > squeezing or cooling. > > > > > Contraction by cooling is "really physically contracted", or > > > > "materially contracted", and it is NOT a geometrically contracted > > > > effect. > > > > Indeed, but you act as though this is the ONLY way something can be > > > physically contracted. Not so at all. > > > > > IOW, when a meter stick is "really physically contracted" or > > > > "materially contracted" its physical length or material length is > > > > "physically" or "materially" shorter than the observer's meter stick. > > > > "Physically" does not mean "materially". Never has, Ken. Get that out > > > of your head. It's wrong. > > > > > I don't understand why you insist on hijacking the word "physical" and > > > > give it a different meaning than the standard meaning. > > > > The standard meaning is the meaning given by physicists, since that > > > which is physical is what is studied by physics. > > > Electric field is physical, but it is not material. This should be > > > enough to tell you that what you think is the "standard meaning" has > > > something wrong with it, Ken. > > > > So much of your difficulty in understanding physics, Ken, is that you > > > insist that words mean what you want them to mean and you never ask > > > what they really do mean. If you only asked what some words meant in > > > physics, so much of your misunderstandings would be quickly resolved. > > > > > I don't > > > > understand why you don't except the correct phrase that length > > > > conraction in SR is a "geometric projection effect". > > > > > BTW the physical length or material length of the pole DOES NOT > > > > actually fits between the doors when the doors are closed. The > > > > *geometric projection* of the pole can fit into the barn with both > > > > doors are closed.....the reason is that geometric projection is not > > > > physical or material. > > > > Oh, Ken, Ken, Ken. The doors are both closed at the same time, and the > > > ends of the pole do not touch the doors. The pole is completely inside > > > the barn. > > > Yet you want to insist that the pole is only geometrically inside the > > > barn and not physically inside the barn? Is it physically sticking out > > > of the barn? How does it physically do that without physically making > > > marks on the barn doors where the pole physically hits them? > > > Here's the problem: What you wrote here means that there is material > > or physical contraction. Why? Because the only way that the material > > pole can be completely inside the barn with both doors closed > > simultaneously is that it is physically or materially contracted. > > That is not so, Ken. You see, that is the only way YOU can think of > this happening, and so you assume it IS the only way it can happen. In > this way, you prevent yourself from learning anything new. > > Things can be physically contracted without being materially > contracted. > However, YOU can only think of one way something can be physically > contracted, and that's if it's materially contracted. That's YOUR > limitation, and yours only. No things cannot be physically contracted without materially contracted. The word physical has the meaning of "of matter; material" in the dictionary. I don't understand why you insist to give the word physical a new meaning that is not associated with material. Furthermore in SR there is geometric contraction effect....why don't you use that instead of "physical contraction"? > > > If > > this is true then why do you need the explanation that length > > contraction in SR is a geomrtical projection effect? > > > > Do you see what kind of nonsense your word games get you into? > > > ROTFLOL....it is you who is playing word games. Tom Roberts said that > > length contraction in SR is a geometric projection effect and you said > > that length contraction in SR is a physical > > Yes, physical. define physical. > > > or material effect. > > No, not material. "Physical" does not mean "material". I've repeated > this to you at least 10 times, and yet you continue to make the two > words synonymous when they are not. No matter how many time you repeat a falsehood ....I will not accept it. > > > So who > > should I trust? You or Tom Roberts? I trust Tom Roberts becasue he > > seem to be more knowledgeable than you. > > Ken, Ken, Ken. You see, you are struggling because you're trying to > learn relativity from a NEWSGROUP. No I am not trying to learn relativity from NG. I was trying to point out your missunderstanding the meaning of SR length contraction. And there you have all manner of > people who will say all sorts of things, and many of those people are > just plain whacko, So I guess you are one of those wackos....Right? > and you are forced to choose who you should trust > as the authority to believe. And then you have to make that decision > on who to trust by who "seems" to be more knowledgeable about a > subject that you know nothing about. As I said I trust Tom Roberts more than you because he is more knowledgeable. Ken Seto > > It does not occur to you that the reason why you have struggled to > learn ANYTHING consistently over 15 years is that you are using the > WRONG venue to learn it. A newsgroup is NOT the right place to learn > relativity. Anyone who tries it will spend 15 years learning > practically NOTHING, and will still be confused about who to trust. > > Does it not occur to you that you have been wasting your time by > choosing this venue to provide you with reliable material so that you > can learn relativity? Has it not occurred to you that you would be > better served by spending $40 every few months on a decent book on the > subject? > > > > > > > Ken Seto > > > > > Ken Seto > > > > > > You get so confused about terms like "physically contracted" and > > > > > "materially contracted" and "really contracted", as though they all > > > > > mean the same things. They do not. The sooner you learn the > > > > > distinctions, the better. > > > > > > >.....IOW, not just a geometric projection > > > > > > effect. > > > > > > > > > The physical length cannot fit into the barn is > > > > > > > > an absolute concept and it is not observer dependent. > > > > > > > > I'm sorry, Ken, that is just wrong. > > > > > > > It is not wrong....also assertion is not a valid arguement. > > > > > > Factual matters are decided by documented facts, not argument, Ken. > > > > > The point is not to *convince* you that you are wrong. I'm only > > > > > pointing out when you ARE wrong, and I'd be happy to direct you to > > > > > where you can look up the documented facts. However, there is no point > > > > > in trying to convince you that you are wrong by making a compelling > > > > > argument. I might as well be arguing with a stone pig. > > > > > > > > > > Nor is it contradictory to say that a falling ball has a straight-line > > > > > > > > > trajectory AND a parabolic trajectory in the same fall. Galileo knew > > > > > > > > > that. I don't see why you don't understand that. > > > > > > > > Do you understand what I wrote in this paragraph? Do you see why this > > > > > > > is also not a contradiction? > > > > > > > What you are describing here is a geometric projection of a falling > > > > > > ball in the ship from the shore observer's point of view > > > > > > No, it is a PHYSICAL shape of a trajectory. That is the point. The > > > > > straight line path is a PHYSICAL trajectory. The parabolic path is a > > > > > PHYSICAL trajectory. The falling ball has BOTH a straight line > > > > > physical trajectory AND a parabolic physical trajectory, as seen in > > > > > different frames. What is *measured* is physical. > > > > > > >....this is > > > > > > not the same as in the barn and the pole paradox where you claimed > > > > > > that the pole is physically contracted.- Hide quoted text - > > > > > > - Show quoted text -- Hide quoted text - > > > > > > - Show quoted text -- Hide quoted text - > > > > - Show quoted text -- Hide quoted text - > > > > - Show quoted text -- Hide quoted text - > > - Show quoted text -- Hide quoted text - > > - Show quoted text -
From: Inertial on 11 Feb 2010 19:46 "Paul Stowe" <theaetherist(a)gmail.com> wrote in message news:3b3fb45b-8442-413c-bd96-df4dd57c8b50(a)m35g2000prh.googlegroups.com... > On Feb 11, 1:46 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "Paul Stowe" <theaether...(a)gmail.com> wrote in message >> >> news:e197d580-e4c3-4afa-a4e6-2fbf404412e6(a)l12g2000prg.googlegroups.com... >> >> >> >> >> >> > On Feb 10, 11:16 pm, "Inertial" <relativ...(a)rest.com> wrote: >> >> "Paul Stowe" <theaether...(a)gmail.com> wrote in message >> >> >>news:0db4a675-2ae3-4b9d-af25-9b5f4fac9d55(a)a16g2000pre.googlegroups.com... >> >> >> > On Feb 10, 11:36 am, Ste <ste_ro...(a)hotmail.com> wrote: >> >> >> > {Snip...} >> >> >> >> The question therefore remains, how can the speed of propagation >> >> >> possibly be measured to be constant in all frames. >> >> >> > The answer to your question is actually simple and 'intuitive' if >> >> > you >> >> > think >> >> > about what must happen in a medium. The propagation of any type of >> >> > disturbance travels by 'conduction' from one entity to the next. >> >> > This >> >> > is >> >> > set by the mean speed and spacing. If the medium is >> >> > 'incompressible' >> >> > the >> >> > entities are all touching (spacing is zero) and the entities >> >> > 'infinitely >> >> > hard' In that case, the speed of propagation is infinite, and no >> >> > delta >> >> > 'pressures' are possible 'within the medium. OTOH, in any >> >> > compressible >> >> > medium there is spacing, and the entities have momentum and energy. >> >> > This >> >> > results a distinctive independent set speed by which any >> >> > disturbances >> >> > (like wave propagation) will occur. This is designated as c for >> >> > ANY! >> >> > medium >> >> >> > Now it should be obvious that in the case of a medium it is this >> >> > process >> >> > that always dominates... The speed of sources must, by that >> >> > constraint, >> >> > alter there emission/field profiles to conform to this limitation. >> >> >> > So now, start with a source of a omni-directional wave generator 'at >> >> > rest' >> >> > with respect to the medium. The resulting waves propagate outward >> >> > 'at >> >> > c' >> >> > in all directions, resulting in a perfectly spherical field form. >> >> > Next, >> >> > give this source some speed v, obviously c hasn't changed so, in the >> >> > direction of motion the source is displacing forward at v so each >> >> > wave >> >> > front must be separating 'from the source' at c - v. In the >> >> > perpendicular >> >> > (transverse) direction the wave fronts are still separating from the >> >> > source at c. Thus, for the hemisphere in front of the moving source >> >> > the >> >> > wave field form is no longer spherical, but flatten into an >> >> > ellipsoid. >> >> > Now what happens to the back half??? >> >> >> The opposite >> >> >> > Intuitively you would think >> >> > that >> >> > the wave front would be separating 'from the source' at c + v. >> >> >> It does >> >> >> > However, remember that a wave is an oscillation (a back & forth >> >> > motion) so, >> >> >> Not for light. It is side-to-side >> >> >> > one cycle is c - v and c + v. >> >> >> Nonsense [snip rest] >> >> > From the �Handbook of Physics� (Section 3, Chapter 8 - �Acoustics�, >> > Rev 2 1967), >> >> > �The surfaces of constant sound pressure on the other hand >> > are given by R� = constant, which corresponds to the >> > ellipsoid x'^2 + y^2 + z^2 = constant = R�^2 as pictured >> > in Fig. 8.2. It is interesting to note that the field is >> > the same up and down wind and that the intensity is >> > larger in the directions at right angles to the flow.� >> >> Don't have that book >> >> Each wavefront (for sound), however, forms a sphere around the point from >> which it was emitted. > > Really? What's the general form of the wave equation for that? Why do you need to know the equation for a sphere? >> The source continues to move, so successive wave cycles have the centre >> of >> their spherical wavefront at a different position > > If the field for each source position (instant) could manifest itself > instantaneously maybe, but the field doesn't/can't. No need to be instantaneous > The disturbances > must propagate from the source outward at finite speed. Yes .. in all directions at the same speed wrt the medium. Hence you get a sphere. And as the source is going slower than the speed of propagation in the medium, the overall bounds of the wavefront is always a sphere .. the sphere defined by the leading wavefront. > Thus for > every dx the field propagates the source moves forward some ds... Pretty much what I said > The > result of this is as described in the reference provided, and I > described earlier. Namely, the resulting overall sound field is a > flatten ellipsoid contracted along axis of motion by precisely Sqrt(1 > - [v/c]^2), a.k.a. it undergoes a Lorentz contraction. But a wave-front is spherical. What is a 'sound field', and what do areas of constant pressure have to do with SR? >> What has a surface of constant sound pressure got to do with anything in >> SR? > > Think about it for awhile..... OK .. just did. No answer. So .. seeing it is your claim, what does sound pressure have to do with SR? > >> > Go check it out for yourself. As for using the words "back and forth" >> > I guess I should of said cyclic... >> >> Yes > > Paul Stowe
From: Inertial on 11 Feb 2010 19:59 "kenseto" <kenseto(a)erinet.com> wrote in message news:3ab08ba8-abb2-4ba6-9fb6-d4ae8b396b69(a)z26g2000yqm.googlegroups.com... > On Feb 11, 10:32 am, PD <thedraperfam...(a)gmail.com> wrote: >> That is not so, Ken. You see, that is the only way YOU can think of >> this happening, and so you assume it IS the only way it can happen. In >> this way, you prevent yourself from learning anything new. >> >> Things can be physically contracted without being materially >> contracted. >> However, YOU can only think of one way something can be physically >> contracted, and that's if it's materially contracted. That's YOUR >> limitation, and yours only. > > No things cannot be physically contracted without materially > contracted. The word physical has the meaning of "of matter; material" > in the dictionary. I don't understand why you insist to give the word > physical a new meaning that is not associated with material. > Furthermore in SR there is geometric contraction effect....why don't > you use that instead of "physical contraction"? So you are using 'physical' as a synonym for 'material' .. why not just say 'material' and then we'll all agree with you. As is evident, the word 'physical' is a term that causes confusion. So a ladder tilting over is (by your use of the word) physically unchanged, but it is also true that it is not as tall, and so can it fit through doorway gap that is shorter than the ladder's length. Would *you* describe the tilted ladder passing through the shorter doorway as something 'physical'? Does the ladder physically get to the other side of the doorway? Is the a rotation of a ladder something physical? If so, then you must similarly describe the pole being between the barn doors as physical. If not, then I would agree that length contraction is not 'physical' by your use of the word.
From: kado on 11 Feb 2010 20:20 On Feb 10, 11:34 pm, Ste <ste_ro...(a)hotmail.com> wrote: > snip > > I haven't lost interest, but I must admit I still haven't really got a > clear picture of where the trains are or how they are moving. If > indeed it is unspecified whether they are moving relative to the track > or the clouds, then we may as well just do away with tracks and > lightning, and just talk about two trains that are moving relative to > each other, suspended in the air against a blank background. The > involvement of tracks and clouds just complicates the matter. I see by this mess of all these posts that no one on this thread seems to truly understand Einstein's Theories of Relativity OR the Philosophy of Idealism upon which Einstein based his theories. The fundamental tenets of this philosophy basically maintains that: Since every phenomenon, object, entity, event, thing, etc., exists only in the mind of man, and as the universe is the sum of its parts, the universe does not exist except as the perception of human (i.e., my, and/or me, myself and I, the human observer's. the human looker's, the human knower's etc.,) understanding. In other words; any foreshortening, contraction, etc., of any measuring rod, ladder, ball, train, etc., moving near the speed of light in any of Einstein's ideas are just perceived (i.e., UNDERSTOOD) and SUPPOSED to contract as tensors. Nowhere in the Philosophy of Idealism or Einstein's relativity is there any mention of any empirical measurement, or for that matter, about any empirical experiments, only thought experiments (i.e., inductive/ deductive reasoning) and the faith on the validity of mathematics (i.e., mathematical physics), that is based on Descartes notion that: mathematics rules physics, which in turn was prompted by the Philosophy of Idealism. Put another way; what ever moving entity you are discussing, its just SUPPOSED to contract as the mathematics of tensor mechanics dictates, and there just is not any physical thing to discuss. So all you have to do is determine if human understanding is physical or not. If not, then this brings up the enigma of the validity of the nonphysical. These have a huge impact on what you consider or connote as reality, and what is real and what is not. The Philosophy of Idealism places the human above Nature and/or God, so cannot be true. Furthermore, this arrogant philosophy greatly distorts any concept of reality, and what is real and what is not. So I maintain that it is better suited for the scope of schizophrenia than of the realm of the rational. All these are addressed in greater detail in my copyrighted, but yet to be published treatise titled: The Search for Reality and the Truths. D.Y. Kadoshima P.S. The last two posts of mine in the thread in this newsgroup titled A simple Q, but not a simple A, may also help clarify some of your questions. Reading all my posts cannot hurt, and may possibly expand your knowledge of physics.
From: Inertial on 11 Feb 2010 20:28
<kado(a)nventure.com> wrote in message news:36110e33-3db3-4eb1-b1c6-34d888314332(a)b10g2000vbh.googlegroups.com... > On Feb 10, 11:34 pm, Ste <ste_ro...(a)hotmail.com> wrote: > >> > snip >> >> I haven't lost interest, but I must admit I still haven't really got a >> clear picture of where the trains are or how they are moving. If >> indeed it is unspecified whether they are moving relative to the track >> or the clouds, then we may as well just do away with tracks and >> lightning, and just talk about two trains that are moving relative to >> each other, suspended in the air against a blank background. The >> involvement of tracks and clouds just complicates the matter. > > I see by this mess of all these posts that no one on this > thread seems to truly understand Einstein's Theories of > Relativity OR the Philosophy of Idealism upon which > Einstein based his theories. There's certainly a lot of misunderstanding. But I doubt that no one understands. > The fundamental tenets of > this philosophy basically maintains that: > > Since every phenomenon, object, entity, event, thing, > etc., exists only in the mind of man, Nope .. totally wrong. That has nothing to do with SR > and as the universe > is the sum of its parts, the universe does not exist > except as the perception of human (i.e., my, and/or me, > myself and I, the human observer's. the human looker's, > the human knower's etc.,) understanding. Nope .. totally wrong. That has nothing to do with SR > In other words; any foreshortening, contraction, etc., of > any measuring rod, ladder, ball, train, etc., moving near > the speed of light in any of Einstein's ideas are just > perceived (i.e., UNDERSTOOD) and SUPPOSED to > contract as tensors. So, you don't understand the physics of SR either. Join Ken et al. [snip rest of nonsense] |