A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Peter Webb on 27 Feb 2010 00:50 > > My only contention is that it is *not realistic* to say that from the > barn frame frame the ladder contracts and fits inside, while saying > that from the ladder frame it is the barn that contracts and the doors > actually never shut simultaneously. It is simply not realistic. If > such a thing appears to happen, then it is obviously an artefact of > subjective observation. > Better not tell GPS units, particle accelerators, space probes, or light from distant stars that length contraction is not realistic, or they might all suddenly decide not to undergo length contraction, with obvious huge problems for navigation, particle physicists, astronomers etc all of whom rely upon things behaving in a not realistic manner which you don't understand for correct operation. We *know* that you don't understand relativistic length contraction, or anything else to do with SR or any other physics discovered in the last 300 years. You don't have to keep telling us. A solution has been offered many times. It doesn't seem realistic to you because you don't understand SR, and have no insight into it. This is because you do not have the basic mathematical skills to understand the things which would give you insight - Minkowski being the most obvious. Nobody is born understanding this stuff, you have to study it. You have not done so, hence your lack of understanding. So, buy a book on Relativity, preferably one which explains how Minkowski modeled SR, feel free to ask away if you don't understand what you read. But don't complain you don't understand physics if you don't have basic maths skills. It would be like saying you can't understand books written in Dutch when you can't speak Dutch. Want to learn about Dutch literature, learn Dutch. Want to learn physics, learn mathematics. Simple, really.
From: Peter Webb on 27 Feb 2010 00:54 "Paul Stowe" <theaetherist(a)gmail.com> wrote in message news:73c93327-144e-4595-ada1-4bfff749884c(a)e19g2000prn.googlegroups.com... On Feb 26, 5:00 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 26 Feb, 18:20, PD <thedraperfam...(a)gmail.com> wrote: > > > On Feb 26, 1:31 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > In what sense can it be said to work if it doesn't predict what is > > > > observed. > > > > It does predict what is observed, but only in a very loose way, > > > No. It *accommodates*, it does not *predict*. And this is where there > > is a difference. > > It is one thing to say that a certain behavior is *conceivable* within > > a mental picture, it is another thing entirely to say that it is > > *demanded* from a model. A prediction is usually precise enough where > > it will be able to say, "you will see behavior X in quantity Qx, > > behavior Y in quantity Qy, and behavior Z in quantity Qz, but you will > > NEVER see behavior W and you will not see behavior Z in any other > > quantity." This your mental picture does not do. > > But it does for example. My mental picture says that gravity will > never become stronger with increasing distance. That is a firm > prediction. But, in both the center of a spiral galaxy and the center of mass the gravitational potential is zero, increasing in strength until one reaches either the surface of a solid planet or, in the case of a galaxy the rotation speed verses area density starts to drop off. So, while I understand where you are coming from, technically, you're wrong. _____________________________ In fact, the earth's gravity increases for a period as you go further underground. As you said, the exact opposite of the only prediction we have heard from the model. Paul Stowe
From: Paul Stowe on 27 Feb 2010 01:10 On Feb 26, 9:29 pm, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "Paul Stowe" <theaether...(a)gmail.com> wrote in message > > news:4a4b9e26-7b46-4c0b-b41d-f9fda83efe1c(a)b9g2000pri.googlegroups.com... > On Feb 25, 11:27 pm, "Peter Webb" > > > Probably because relativistic mass increase is now an obsolete > > concept. As for e = mc^2 again, while a consequence of the relativity > > it is now considered that mass remains unchanged and the frame > > dependent momentum/energy is solely an artifact of relative velocity. > > As for 1905, Einstein penned Longitudinal mass and transverse mass > > formulas (10. Dynamics of the Slowly Accelerated Electron > > ofhttp://www.fourmilab.ch/etexts/einstein/specrel/www/) identical to > > Lorentz's of 1904, quote: > > > "This theory was further developed by Abraham (1902), who first used > > the terms longitudinal and transverse mass for Lorentz's two masses. > > However, Abraham's expressions were more complicated than those of > > Lorentz. Lorentz himself expanded his 1899 ideas in his famous 1904 > > paper, where he set the factor to unity.[A 3] So, according to this > > theory no body can reach the speed of light because the MASS BECOMES > > INFINITELY LARGE at this velocity." > > > So, where's the difference of and mathematical significance? > > > ___________________________________ > > Like I said, Lorentz lacks (amongst other things) expressions for momentum > > and energy, including the now famous e=mc^2. This was not part of Lorentz; > > it is part of Special Relativity. > > "In fact, one can be far more general and precise: any theorem of LET > is also a theorem of SR, and any theorem of SR is a theorem of LET. > IOW: they are equivalent theories (i.e. they share the same set of > theorems). As the theorems of a theory are the basis for comparing the > theory to experiment, it is clear that SR and LET are experimentally > indistinguishable." - Tom Roberts, 22 Nov 2003 - > > _____________________________ > Funny, we were discussing the theories of Lorentz prior to publishing of SR. > LET was not the theory of Lorentz prior to SR. Easy mistake for you to make. Really??? "For >7 years in this newsgroup, the phrase "Lorentz Ether Theory" (LET) has meant the theory based on Lorentz's 1904 paper, "Electromagnetic Phenomena in a System Moving with Any Velocity Less than that of Light", and all logical and mathematical deductions from the presentation in that paper." - Tom Roberts, 22 Nov 2003 - (Same article...) Please note 1904 Paper! Your denial not withstanding, BUT YES! the theory of Lorentz PRIOR TO Einstein's 1905 paper. > That includes all 'consequences' of the theory, including energy/ > momentum. > > __________________________ > Sure. Show me where Lorentz said e=mc^2. The same place Lorentz wrote about the PoR or Ros... > > > > > So the only thing that you can bring to the table is some > > > > > philosophical > > > > > interpretation of what is "really" going on. > > > > > So what? That all Einstein brought to the table! > > > > > _________________________________ > > > > Ummm ... time dilation? Mass increase in changing reference frames? > > > > The > > > > equivalence of mass-energy? > > > > Mass increase? > > > > _________________________________ > > > Yeah. The measured mass of objects is a function of the reference frame > > > in > > > which it measured. Learn some SR before telling us it is wrong. Or learn > > > some SR before telling us its correct, if you prefer. > > > Get up to date. > > _______________________________ > > I don't think there is much point in me talking about relativistic mass to > > somebody who doesn't understand basic concepts of SR. I am trying to dumb > > this down as much as I can. > > "Ah, arrogance AND stupidity all in the same package, how efficient of > you..." > > Tell us how to measure the 'mass' of an object moving at 0.99c > relative to you. Would you not 'measure' momentum/energy and > 'compute' a mass equivalence? When and IF you brought it to 'rest' > there is only rest mass. The relativistic mass vanished, dissipated > as energy. > > __________________________ > Gee, so you have read an introductory book on SR. Your point is .... My point is, the is no relativistic mass, there is, instead, there is a non-linear increase of in the momentum/kinetic energy of moving masses and not all momentum/energy is massive.... It it were photons would be massive. Thus the original quandary, "Mass Increase?" > > Nobody is here to be educated. If the posters who disbelieve SR wanted to > > be > > educated, they would buy a book instead of trolling here. > > Please show me where I said I disbelieve in the mathematical > formulation used in SR? For the record, the math is right, the > experiments sound. Note what Tom Roberts wrote above, one does not > have to buy SR's philosophy to accept the mathematical formulation. > > ________________________________ > Ummm ... SR's "philosophy"? > > SR is a collection of equations. The very same ones as Lorentz's as Tom Roberts explained... So, given that LET and SR have the very same collection of equations and consequences, what's the difference between them? > "Existentialism", now that's a philosophy. Yes, it is. > > OK, tell me what it means for something to a property (in this case actual > > speed) that cannot in any way be measured? > > Sure it can, it's called the CMBR doppler. General Relativist have > come to accept the CMBR as the preferred reference frame for > astrophysical computations. > > ________________________________ > Ummm ... CMBR is measured. And it is not a pre3ferred reference frame for > astrophyscial calculations, unless you can point to a single astrophysical > calculation that uses it. http://scholar.google.com/scholar?q=CMB+preferred+frame&hl=en&btnG=Search&as_sdt=2001&as_sdtp=on > > Speculation, had Einstein not published 1905 both Lorentz and Poincare > > would have probably gotten E=mc^2 with a year or two. Poincare was > > almost there without and input from Einstein. It is a direct > > consequence of Lorentz invariance. > > > ______________________________ > > Ohh, OK, Lorentz is *not* the same as SR, and Lorentz was (according to > > you) > > at least a year or two away from developing SR. This is *not* what you > > claimed above, and this is exactly the point I have been disputing. Now > > you > > seem to agree you were wrong. > > LET is mathematically identical to the tenets of SR. Thus all > consequences of SR are also contained in LET. There is no mass > increase, instead there is kinetic energy and momentum for massive > objects when moving relative to an observer. This understanding has > lead to a general abandonment of the concept of relativistic mass. I > think you'll find the terms invariant mass, proper length, proper time > used in more modern discussions. > ________________________________ > But, funnily enough, none of these were articulated by Lorentz, were they? Actually they were, but not prior to 1905. And, Lorentz never abandoned his aetherial perspective. Paul Stowe
From: Peter Webb on 27 Feb 2010 01:55 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:2268f44a-518e-43b4-a3f8-a610f4e89e89(a)o30g2000yqb.googlegroups.com... > On 26 Feb, 12:31, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > wrote: >> "Ste" <ste_ro...(a)hotmail.com> wrote in message >> >> About this gravity thing. I am having a great deal of difficulty forming >> a >> mental picture of how it is supposed to work. > > At a fundamental level, I do too. > > > >> If the planets are separated >> by vacuum, how could one object possibly pull on another object when >> there >> is nothing between them? For that matter, how does one particle manage to >> pull on every other particle in the Universe at the same time? Are you >> positing some array of invisible springs, 10^160 of them, connecting the >> 10^80 particles in the Universe? > > I think a more credible argument is that there *is* in fact something > in between the objects. > > > >> Frankly, I find the suggestion that each time I move my finger to type >> these >> invisible gravity springs cause every other particle in the Universe to >> move >> ludicrous. Apart from anything else, how is this spooky action at a >> distance >> supposed to work, physically? Springs and levers? What is gravity >> supposed >> to be, physically? > > I don't find it hard to believe that every movement of the finger > could have an effect on every other particle of the universe. In terms > of what gravity is and how it works, that remains to be explained. Ohhh, so your mental model of the solar system contains "gravity", yet your mental model of the solar system provides no physical explanation of what it "really" is. Funny, you complained about SR and Minkowski for having components for which you have no physical model. Yet your own theory of the solar system contains concepts such as gravity which have no physical explanation at all within the model. Newton's theory of gravitation and SR are not at all different in that respect. Newton's theory of gravity says nothing at all about what gravity "really" is. SR says nothing about what length contraction "really" is. The theories don't need to. The equations all work; the rest is philosophy. In your case, bad philosophy.
From: Peter Webb on 27 Feb 2010 02:02
"Ste" <ste_rose0(a)hotmail.com> wrote in message news:f1c82fe9-c833-4262-9bca-d62d9181c8b0(a)i39g2000yqm.googlegroups.com... On 26 Feb, 12:52, "Inertial" <relativ...(a)rest.com> wrote: > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > Of course I'm not claiming to know anything profound about the solar > > system. The conceptual model has been accepted for centuries, and I'm > > not pretending to add anything new to it. The point I was making about > > it is that the conceptual model is required to give any real meaning > > to the equations. > > We already have such model .. that's the whole POINT of physics .. it is > modeling reality. How reality behaves is the meaning to the equations .. > they describe what is going on. Then show the equations to a child. Ask him if he understands what is going on. And remember, you're not allowed to mention the conceptual aspect, or appeal to sensory perception. You must only use the equations. If these equations alone describe what is going on meaningfully, then the child ought to understand immediately. ___________________________________ Why a child? Why not try and explain the equations of SR to a nematode worm? If they really do encompass SR, then the nematode worm should understand SR immediately. Or so your logic would suggest. Here are the facts. To fully understand SR, you need to be reasonably intelligent, have a basic maths ability, and have some knowledge of physics. A child, a nematode worm, and yourself all miss out on some or all of these. If you want to understand SR, you are going to need to learn some maths and physics. Some things actually require work. Sorry. |