Is Length Contraction in SR physical??
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From: Sebastian Garth on 2 Feb 2010 01:46 On Feb 1, 8:03 pm, kenseto <kens...(a)erinet.com> wrote: > I suggest that you go argue with your SR brother Tom Roberts. He said: > "Generally, they would consider a "physical length contraction" to > mean that the object ITSELF gets > physically shorter. This is manifestly not so in SR". Not true. Length contraction is a truly physical phenomena which is absolutely measurable. Fire two laser beams perpendicularly across the front and rear of the moving object; the change in length is not an illusion - within the observer's frame of reference, the object indeed occupies less space.
From: Helmut Wabnig hwabnig on 2 Feb 2010 04:19 On Mon, 1 Feb 2010 22:46:38 -0800 (PST), Sebastian Garth <sebastiangarth(a)gmail.com> wrote: >On Feb 1, 8:03�pm, kenseto <kens...(a)erinet.com> wrote: >> I suggest that you go argue with your SR brother Tom Roberts. He said: >> "Generally, they would consider a "physical length contraction" to >> mean that the object ITSELF gets >> physically shorter. This is manifestly not so in SR". > >Not true. Length contraction is a truly physical phenomena which is >absolutely measurable. Fire two laser beams perpendicularly across the >front and rear of the moving object; the change in length is not an >illusion - within the observer's frame of reference, the object indeed >occupies less space. ################################################# >within the observer's frame of reference, the object indeed >occupies less space. ################################################# "as the observer sees it" (measures it) Then indeed it is an illusion. See what Observers see: http://hyperphysics.phy-astr.gsu.edu/hbase/geoopt/optpic/brokpen.jpg w.
From: artful on 2 Feb 2010 05:26 On Feb 2, 8:19 pm, Helmut Wabnig <hwabnig@ .- --- -. dotat> wrote: > On Mon, 1 Feb 2010 22:46:38 -0800 (PST), Sebastian Garth > > <sebastianga...(a)gmail.com> wrote: > >On Feb 1, 8:03 pm, kenseto <kens...(a)erinet.com> wrote: > >> I suggest that you go argue with your SR brother Tom Roberts. He said: > >> "Generally, they would consider a "physical length contraction" to > >> mean that the object ITSELF gets > >> physically shorter. This is manifestly not so in SR". > > >Not true. Length contraction is a truly physical phenomena which is > >absolutely measurable. Fire two laser beams perpendicularly across the > >front and rear of the moving object; the change in length is not an > >illusion - within the observer's frame of reference, the object indeed > >occupies less space. > > #################################################>within the observer's frame of reference, the object indeed > >occupies less space. > > ################################################# > > "as the observer sees it" (measures it) > > Then indeed it is an illusion. So location, velocity, momentum and energy are all illusions too? They all depend on how "the observer sees it".
From: "Juan R." González-Álvarez on 2 Feb 2010 07:37 eric gisse wrote on Mon, 01 Feb 2010 08:07:49 -0800: > Juan R. González-Álvarez wrote: > >> eric gisse wrote on Mon, 01 Feb 2010 08:08:39 -0800: >> >>> kenseto(a)erinet.com wrote: >>> >>>> Is Length Contraction in SR physical?? >>> >>> No, just as it has been explained to you repeatedly since the mid >>> 90's. >>> >>> [...] >> >> From Tom Roberts page: >> >> "At this time there are no direct tests of length contraction, as >> measuring the length of a moving object to the precision required has >> not been feasible. There is, however, a demonstration that it occurs: >> >> A current-carrying wire is observed to be electrically neutral in its >> rest frame, and a nearby charged particle at rest in that frame is >> unaffected by the current. A nearby charged particle that is moving >> parallel to the wire, however, is subject to a magnetic force that is >> related to its speed relative to the wire. If one considers the >> situation in the rest frame of a charge moving with the drift >> velocity of the electrons in the wire, the force is purely >> electrostatic due to the different length contractions of the >> positive and negative charges in the wire (the former are fixed >> relative to the wire, while the latter are mobile with drift >> velocities of a few mm per second). This approach gives the correct >> quantitative value of the magnetic force in the wire frame." >> >> P.S: Do you want your new 'brilliant' post to be added to your profile >> as USENET crackpot? :-D > > Why don't you publish the stuff you've been talking about for years > first instead of trying to get involved in another argument of > semantics? I will take this Red-Herring as a sound "Yes, please add my message to the others" :-D > >> P.P.S: Newsgroup sniped by Eric re-added to the reply. >> P.P.P.S: Newsgroup sniped by Eric re-added to the reply. -- http://www.canonicalscience.org/ BLOG: http://www.canonicalscience.org/en/publicationzone/canonicalsciencetoday/canonicalsciencetoday.html
From: Pete on 2 Feb 2010 07:43
Imagine two speres joined by a thread which is extended to its full length but not under tension Gently accelerate the two spheres at exactly the same rate. Does Lorentz contraction increase the tension in the thread (and eventually cause it to break)? |