Is Length Contraction in SR physical??
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From: Ste on 8 Feb 2010 05:20 On 8 Feb, 05:42, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > >> The link I gave you above explains exactly what would happen in SLAC if > >> the > >> length of the accelerator was not foreshortened by SR, ie it wouldn't > >> work. > >> It does work, almost every day. > > > The only "evidence" on that page is that when tauons move at speed, > > they appear to travel further before decaying, an appearance which no > > one denies. It then goes on to speculate what the tauon would "see" > > from within its own reference frame. > > > But let me ask you, how is the decay event detected? > > Why? > > Its certainly not optically. > > SLAC uses a range of detectors. These would typically operate by the decay > particles (*NOT* EMR waves) causing a physical phase change in a material > ("cloud chambers", now very old), or mediating a chemical reaction (film), > or providing energy to a CCD array. *None* of these use EMR. So *which* of these detection methods were used in your evidence, and what are the results that you have? > Well, now you have: > > 1. Been given links to lots of proofs of SR, For crying out loud, I am *not* setting out to disprove SR. > 2. Been given links to experimental demonstrations of SR length contraction > (in particle accelerators) No I haven't. I was palmed off with a childish summary of existing scientific opinion. > 3. Had this and other things explained to you by people who *do* understand > the maths and have studied physics for *more* than an entire month. No I haven't had anything explained to me in a way that I understand. Indeed, discussions here have predominantly been of either a personal or a philosophical nature, with hardly any physics discussed by reference to coherent argument and compelling evidence. > If you have any questions concerning SR, I am happy to answer them. > > If you think SR is wrong, then I couldn't care less. That somebody with no > expertise in mathematics or physics doesn't believe in (or understand) SR is > hardly surprising. Some things require mathematics and more than a month's > study to understand. Only cranks believe otherwise. Do I have to keep repeating until I'm blue in the face, *I don't disagree with SR*! What I disagree with is the physical interpretation that is placed upon it (or indeed, the *lack* of physical interpretation).
From: Ste on 8 Feb 2010 05:56 On 8 Feb, 10:08, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 8, 5:05 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > On 8 Feb, 04:29, mpalenik <markpale...(a)gmail.com> wrote: > > > > On Feb 7, 11:16 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > But let me ask you, how is the decay event detected?- Hide quoted text - > > > > Is it really that hard to click the link?http://www2.slac.stanford.edu/vvc/detectors.html > > > > Just so you know, it's not done by sending a beam of light at the > > > particle or anything like that, which would be nearly impossible to do > > > anyway. > > > I had a quick glance at some of the pages and links on that site, and > > it seems to be aimed at 8-year-old children, or the sort of summary > > you'd expect to find in a newspaper - as though anyone in this > > discussion here ought to care that "the complete detector weights > > 4,000 tons and stands six stories tall". > > > To reiterate, if you want to have a serious discussion, then provide > > *real evidence*, and expect me to ask some questions. > > This link describes perfectly well how the detector works. For > example, follow the link for the vertex detector:http://www2.slac.stanford.edu/vvc/detectors/vertex.html-- it says > that the vertex detector consists of CCDs for detecting charged > particles that collide with it, it's the innermost layer, has the most > accurate detection capabilities, and even gives an approximate > resolution. What do you think you need to know that isn't on this > page? We seem to be getting somewhere now. I can basically understand the principle of how that carries out a detection. Now, do you have any data that plots detections and velocities, at different speeds?
From: mpalenik on 8 Feb 2010 06:27 On Feb 8, 5:20 am, Ste <ste_ro...(a)hotmail.com> wrote: > > Do I have to keep repeating until I'm blue in the face, *I don't > disagree with SR*! What I disagree with is the physical interpretation > that is placed upon it (or indeed, the *lack* of physical > interpretation).- Hide quoted text - > But you do disagree with SR. 1) Einstein specifically says in his paper that he one of the postulates he is using is that the speed of light is the same in every reference frame. You explicitly denied this in the other thread. 2) SR predicts length contractions, which you have specifically denied. Propagation delays will only give rise to length contractions if the moving object is viewed from behind--and these *do not* mathematically match those predicted by SR. Not only that, but when viewed from the front, one would see length expansions, and from the side one would see nothing at all. 3) SR is meant to be used *after* you account for propagation delays. It had been known that light moves with a finite speed for hundreds of years. Propagation delays were even used to *measure* the speed of light back when the moons of Jupiter were first discovered (by measuring the changes in their apparent speed as they moved toward and away from the earth). You, however, insist that SR is *due to* propagation delays, even though people had already known how to account for them for centuries. 4) You disagree with (or rather, flat out ignore) the experimental evidence on which it is based: namely, the Michaelson-Morely type experiments. 5) You have never explained how an optical phenomenon could give rise to the relativistic energy momentum formula E^2 = p^2c^2 + m^2c^4, instead of the Newtonian formula E = 1/2mv^2.
From: mpalenik on 8 Feb 2010 06:40 On Feb 8, 6:32 am, Ste <ste_ro...(a)hotmail.com> wrote: > I have yet to understand how they rule out the stationary aether > hypothesis. Indeed, as I understand the experiment, the reduced speed > of light in the direction of travel is supposed to reduce the > intensity of light that travels in that direction, and therefore > affect the appearance of the interference pattern. No, the path length is different, not the intensity. The difference in path length is what causes interference. Intensity has nothing to do with it (other than determining the brightness of the interference pattern). The reason there is an interference pattern is because the two beams of light are out of phase. Phase is related to the (fractional) number of wavelengths that the light traverses when it moves. > However, as I've > said, if the reduced speed of light in a certain direction is > compensated for by an increase in intensity in that direction, then > there would be no effect on the interference pattern. That's simply not true. Maybe we simply need to review how interference works. > > Obviously, what I want is for you to either accept this, or identify > the mistake in my reasoning or a mistake in my understanding of the > experiment. > > > The experiments in 1 and 2 use interference fringes which are measured > > by their LOCATION, which is NOT sensitive to luminosity. The only > > thing luminosity could effect is the brightness of the fringes. Even > > if the two interfering beams have different luminosities, the same > > fringes would appear, they just wouldn't get as dark in the dark spots > > or as bright in the bright spots. So your contention that changes in > > luminosity could effect these measurements is wrong. > > Not if the change in luminosity is *directional*. Clearly, a fringe > shift can be offset by a *directional* bias in the luminosity change. > Surely you agree with that?- Hide quoted text - How would intensity affect the location of the interference pattern?
From: Ste on 8 Feb 2010 07:27
On 8 Feb, 11:27, mpalenik <markpale...(a)gmail.com> wrote: > On Feb 8, 5:20 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > Do I have to keep repeating until I'm blue in the face, *I don't > > disagree with SR*! What I disagree with is the physical interpretation > > that is placed upon it (or indeed, the *lack* of physical > > interpretation).- Hide quoted text - > > But you do disagree with SR. > > 1) Einstein specifically says in his paper that he one of the > postulates he is using is that the speed of light is the same in every > reference frame. You explicitly denied this in the other thread. That can be interpreted more than one way. Even *my* hypothesis rests on a "speed of light constant in all frames" - because of course, the speed of light is always measured relative to the medium in my hypothesis. > 2) SR predicts length contractions, which you have specifically > denied. I haven't "denied" them in the sense of "utterly ruled out". What I have said is that there is no physical experimental evidence for it, and that this, in conjunction with the fact that many people seem to be unclear about the physical basis of SR, then the matter remains uncertain for me. > Propagation delays will only give rise to length contractions > if the moving object is viewed from behind--and these *do not* > mathematically match those predicted by SR. Indeed, but in any event that remains to be experimentally verified and physically explained. > Not only that, but when > viewed from the front, one would see length expansions, and from the > side one would see nothing at all. Well, from the side one *would* see an effect, but nothing we need to concern ourselves with for the sake of this argument. > 3) SR is meant to be used *after* you account for propagation delays. > It had been known that light moves with a finite speed for hundreds of > years. Propagation delays were even used to *measure* the speed of > light back when the moons of Jupiter were first discovered (by > measuring the changes in their apparent speed as they moved toward and > away from the earth). You, however, insist that SR is *due to* > propagation delays, even though people had already known how to > account for them for centuries. They clearly didn't know how to geometrically account for these effects, otherwise relativity would have added nothing. > 4) You disagree with (or rather, flat out ignore) the experimental > evidence on which it is based: namely, the Michaelson-Morely type > experiments. No I don't ignore it, and I'm quite willing to discuss it, and I am on one of the other threads. > 5) You have never explained how an optical phenomenon could give rise > to the relativistic energy momentum formula E^2 = p^2c^2 + m^2c^4, > instead of the Newtonian formula E = 1/2mv^2. It really depends on what you mean by an "optical phenomenon". As I say, I'm not challenging the maths of SR. What I'm challenging is the physical basis that is apparently offered to explain it. |