Is Length Contraction in SR physical??
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From: PD on 6 Feb 2010 22:57 On Feb 6, 9:02 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 6 Feb, 17:16, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 5, 8:14 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 5 Feb, 16:00, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 4, 9:57 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > On 5 Feb, 02:48, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> > > > > > wrote: > > > > > > > "Ste" <ste_ro...(a)hotmail.com> wrote in message > > > > > > >news:3979bca1-a35e-4399-bc71-75d2fc680757(a)21g2000yqj.googlegroups.com... > > > > > > On 5 Feb, 01:12, artful <artful...(a)hotmail.com> wrote: > > > > > > > > On Feb 5, 11:49 am, kenseto <kens...(a)erinet.com> wrote: > > > > > > > > > On Feb 4, 6:04 pm, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > > > > On Feb 4, 5:59 pm, "kens...(a)erinet.com" <kens...(a)erinet.com> wrote: > > > > > > > > > > > It it does violate the PoR. You made the contradcictory claims that > > > > > > > > > > the pole can fit into the barn physically (materially) an at the > > > > > > > > > > same > > > > > > > > > > time you claim that the pole cannot fit into the barn physically > > > > > > > > > > (materially)......that a violation of the PoR. > > > > > > > > > > No. The doors are not closed simultaneously in the pole's frame, nor > > > > > > > > > are the two ends of the pole simultaneously in the barn in the pole's > > > > > > > > > reference frame. In the barn's frame, the two ends of the pole are in > > > > > > > > > the barn simultaneously and the doors shut simultaneously.. In the > > > > > > > > > pole's frame, the two ends of the pole are in the barn at different > > > > > > > > > times and the doors shut at different times. > > > > > > > > > Sigh..You are making the contradictory claims: > > > > > > > > 1. The pole can fit into the barn with both doors close > > > > > > > > simultaneously. > > > > > > > > In the frame of the barn > > > > > > > > > 2. The pole cannot fit into the barn with both doors close > > > > > > > > simultaneously. > > > > > > > > In the frame of the pole > > > > > > > > Two different meanings for 'simultaneously'. So they are not > > > > > > > contradictory > > > > > > > > You really are not very good at thinking or arguing logically.. > > > > > > > He seems perfectly reasonable to me. > > > > > > > He's saying that, if one stands in the middle of the barn equidistant > > > > > > from the doors on each side, and one closes the doors simultaneously > > > > > > (i.e. what I would call "absolutely simultaneously", but which for > > > > > > conveience we'll say "simultaneous according to an observer standing > > > > > > equidistant from each door), then is it possible that both doors can > > > > > > appear closed while the ladder is observed to be inside the barn. > > > > > > > It's a simple question, and the answer is "no!". > > > > > > > ______________________________ > > > > > > Its a simple question, and the answer is "yes". It is quite easy to devise > > > > > > an inertial frame in which the doors both appear closed and the ladder is > > > > > > fully contained in the barn. > > > > > > The question wasn't whether "an inertial frame can be devised...".. > > > > > Even I can think of situations where it would *appear* that the ladder > > > > > was inside and both doors closed. The question is whether this is an > > > > > artefact of observation, or whether the ladder is actually inside with > > > > > both doors closed. The answer remains "no, the ladder does not fit > > > > > inside with both doors closed". > > > > > There is a simple test. > > > > We can determine whether the doors closed simultaneously. We do this > > > > using the test of simultaneity I indicated to you above: > > > > 1. Have the door-closings generate signals that travel at identical > > > > speeds from either event. > > > > 2. Have a detector positioned at equal distance from the barn doors.. > > > > 3. If the detector receives the signals from the barn door-closings at > > > > the same time, then the two doors closed simultaneously unambiguously. > > > > You and I have agreed on this procedure. > > > > If the detector is stationary, then yes we agree that this determines > > > simultaneity. > > > > > Secondly, we can determine whether any part of the pole was outside > > > > the barn when those doors were closed by looking for the marks the > > > > ends of the pole would have made on the door. In the absence of those > > > > marks, we can safely conclude that the entire pole was inside the barn > > > > at the time the doors were closed. > > > > Agreed. I would expect this test is definitive, were it possible to > > > carry out. > > > And this has been tested in equivalent experiment. Documented. > > Has it really? Which experiment was that, because my sources say that > length contraction has *never* been experimentally observed. I already told you the answer to that. Please look again. > > > Seto does not read experimental papers, because he finds them > > confusing. So instead he believes what makes sense to him, rather than > > letting experimental results tell him something different. > > You have to concede at least the possibility Paul that the reason Ken > finds them confusing, and so do I, is because *we* can see that they > rest on certain assumptions. That is, assumptions that you've > internalised, and assumptions which me and Ken reject. In Seto's case, it has more to do with thinking that SR says something it does not. I haven't yet figured out whether you are in the same boat. The only assumptions I make are those that have testable consequences. Which ones of those do you think I have that you reject?
From: Peter Webb on 6 Feb 2010 23:01 "Ste" <ste_rose0(a)hotmail.com> wrote in message news:19455b6b-0c13-4152-9769-685bbaa36351(a)o3g2000yqb.googlegroups.com... On 6 Feb, 20:32, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 5, 8:40 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > On 5 Feb, 18:43, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Feb 5, 12:59 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > It's laughable that two people who already claim to understand are > > > > patting themselves on the back for coming up with an allegedly > > > > "impressive" explantion, and yet the people to whom the concept was > > > > to > > > > be explained are still not convinced. > > > > I continue to be mystified by your expectation that it is the > > > objective of physicists to compellingly explain physics to > > > nonphysicists. > > > If they are *purporting* to explain, then it should be explanatory. > > That depends. It may be completely explanatory to someone with a bit > more background, while still a mystery to those missing a few key > concepts. > I disagree that for something to be explanatory, it must be > explanatory to *anyone*. I'm not saying it needs to be explanatory to anyone Paul. I'm saying that if you are *purporting* to explain something to a particular individual, then it is utterly risible for two people who already understand to be patting themselves on the back for conceiving an "impressive" explanation which actually left no impression at all on the person who needed an explanation, and to whom the explanaton was *purportedly* being given. ____________________________________ Pity you didn't understand the explanation. Some things are hard. Some things are also too complicated to expect strangers to explain to you in a newsgroup. You should buy a book, or do some googling on Minkowski space-time.
From: PD on 6 Feb 2010 23:02 On Feb 6, 9:19 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 6 Feb, 20:17, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 5, 8:16 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 5 Feb, 16:02, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 4, 8:16 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > On 5 Feb, 00:49, kenseto <kens...(a)erinet.com> wrote: > > > > > > > On Feb 4, 6:04 pm, mpalenik <markpale...(a)gmail.com> wrote: > > > > > > > > On Feb 4, 5:59 pm, "kens...(a)erinet.com" <kens...(a)erinet.com> wrote: > > > > > > > > > It it does violate the PoR. You made the contradcictory claims that > > > > > > > > the pole can fit into the barn physically (materially) an at the same > > > > > > > > time you claim that the pole cannot fit into the barn physically > > > > > > > > (materially)......that a violation of the PoR. > > > > > > > > No. The doors are not closed simultaneously in the pole's frame, nor > > > > > > > are the two ends of the pole simultaneously in the barn in the pole's > > > > > > > reference frame. In the barn's frame, the two ends of the pole are in > > > > > > > the barn simultaneously and the doors shut simultaneously. In the > > > > > > > pole's frame, the two ends of the pole are in the barn at different > > > > > > > times and the doors shut at different times. > > > > > > > Sigh..You are making the contradictory claims: > > > > > > 1. The pole can fit into the barn with both doors close > > > > > > simultaneously. > > > > > > 2. The pole cannot fit into the barn with both doors close > > > > > > simultaneously. > > > > > > Take comfort Ken that at least there's someone here who understands > > > > > your simple questions. > > > > > So far it appears that there are at least two people confused and > > > > incredulous. > > > > Ken has been confused about this for 15 years. We'll soon see whether > > > > you can be unconfused at the rate that most freshman students become > > > > unconfused about it. > > > > I don't know Ken's past history, but certainly he seems to be asking a > > > fairly reasonable questions this time - and judging by the responses, > > > it's a question that children get taught not to ask! > > > 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. > > Well I can assure you I wouldn't tolerate this crowd for 15 years, but > I'm hoping that perhaps I can articulate myself better than Ken and > make some progress. If not, then I'll comfort myself with Einstein's > words that "the only thing that is infinite is human stupidity". Nice to see you've already established the outcome of this conversation. That is, it is not entertained that you will be convinced of anything differently than what you now hold. The only question is whether you'll convince anyone else, and if not, then it's time to attribute that outcome to stupidity?
From: PD on 6 Feb 2010 23:03 On Feb 6, 9:26 pm, Ste <ste_ro...(a)hotmail.com> wrote: > On 6 Feb, 20:32, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 5, 8:40 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > On 5 Feb, 18:43, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Feb 5, 12:59 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > It's laughable that two people who already claim to understand are > > > > > patting themselves on the back for coming up with an allegedly > > > > > "impressive" explantion, and yet the people to whom the concept was to > > > > > be explained are still not convinced. > > > > > I continue to be mystified by your expectation that it is the > > > > objective of physicists to compellingly explain physics to > > > > nonphysicists. > > > > If they are *purporting* to explain, then it should be explanatory. > > > That depends. It may be completely explanatory to someone with a bit > > more background, while still a mystery to those missing a few key > > concepts. > > I disagree that for something to be explanatory, it must be > > explanatory to *anyone*. > > I'm not saying it needs to be explanatory to anyone Paul. I'm saying > that if you are *purporting* to explain something to a particular > individual, then it is utterly risible for two people who already > understand to be patting themselves on the back for conceiving an > "impressive" explanation which actually left no impression at all on > the person who needed an explanation, and to whom the explanaton was > *purportedly* being given. Oh, I see. Well, perhaps they weren't lauding it as an effective explanation for YOU, but to each other. Did this not occur to you?
From: eric gisse on 6 Feb 2010 23:05
Ste wrote: > On 7 Feb, 02:56, YBM <ybm...(a)nooos.fr.invalid> wrote: >> Ste a �crit : >> >> > On 6 Feb, 10:29, mpalenik <markpale...(a)gmail.com> wrote: >> ... >> > Because *that* is what SR is all about - it is about describing the >> > behaviour of *light*. >> >> No. > > So where is your *observational evidence* that SR describes something > other than light? And I don't mean some Professor's opinion, I mean a > documented *experiment* that proves that SR is not just about optical > effects. > www.google.com "how to use google" http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html [snip rest, unread] |