Is Length Contraction in SR physical??
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From: mpalenik on 9 Feb 2010 00:27 On Feb 9, 12:19 am, Ste <ste_ro...(a)hotmail.com> wrote: > > Incidentally, does frequency have any effect on the absorbtion time of > electromagnetic radiation? The absorption probability (per unit time) goes to zero when averaged over large time scales unless the frequency is equal to the energy difference between two quantum states of the absorbing particle.
From: Ste on 9 Feb 2010 00:38 On 8 Feb, 16:30, PD <thedraperfam...(a)gmail.com> wrote: > > > I don't know why you think that physical models MUST meet your > criteria of "physical" (how YOU understand that term rather than how > physicists understand that term) and "classical" in order to be > acceptable to you. > > Note that the REQUIREMENT you impose that the explanation be classical > is simply an assertion that anything that does not meet the classical > mold is not to be entertained as viable. This is a personal choice on > your part that you will ONLY believe that which meets the classical > physics mold and simply NOT BELIEVE anything else. I've been quite clear Paul. Everyone has axioms, everyone has requirements. Stop framing the issue as though you, or "science", don't. If "science" is happy to talk about "hidden dimensions", "multiverse", etc, then fine, but it's no different from a belief in God. I've been quite clear that my requirements that something be "physical" means that it has to appeal to physical and mechanical intuition. That is, my axioms are that the universe is naturalistic and deterministic in nature - if yours aren't, then fair enough, there is an irreconcilable difference between us - but as I say, there is nothing "scientific" about your beliefs in the sense of "objective", and your appeals to scientific authority take the character of a rhetorical appeal to the majority, except that theoretical scientists are in fact a very small minority.
From: mpalenik on 9 Feb 2010 00:41 On Feb 9, 12:38 am, Ste <ste_ro...(a)hotmail.com> wrote: > On 8 Feb, 16:30, PD <thedraperfam...(a)gmail.com> wrote: > > > > > I don't know why you think that physical models MUST meet your > > criteria of "physical" (how YOU understand that term rather than how > > physicists understand that term) and "classical" in order to be > > acceptable to you. > > > Note that the REQUIREMENT you impose that the explanation be classical > > is simply an assertion that anything that does not meet the classical > > mold is not to be entertained as viable. This is a personal choice on > > your part that you will ONLY believe that which meets the classical > > physics mold and simply NOT BELIEVE anything else. > > I've been quite clear Paul. Everyone has axioms, everyone has > requirements. Stop framing the issue as though you, or "science", > don't. That's a problem when the axioms contradict reality. For example, if I say as one of my axioms that any law of physics must work within the Aristotilian framework, that would preclude my acceptance of any theory that truly models reality. Similarly, your insistance that any physical theory works within a classical framework precludes your acceptance of any theory that truly models reality.
From: BURT on 9 Feb 2010 01:01 On Feb 1, 6:55 am, "kens...(a)erinet.com" <kens...(a)erinet.com> wrote: > Is Length Contraction in SR physical?? > According the most informed SRian, Tom Roberts, the answer to this > question is NO. His answer is that length contraction is the geometric > projection effect of the length of a moving meter stick onto the SR > observer's frame. When a moving meter stick rejoins the stay at home > meter stick they will have the same physical length. Furthermore if > length contraction is physically real how come SR does not predict > length expansion? Is that becasue SR assumes that the observer is in a > state of absolute rest? > > So what does it mean when SR says that a moving meter stick is > contracted? > The answer: > 1. An SR observer assumes that the light path length of his meter > stick is the same as the physical length of his meter stick. > 2. Using this standard the light path length of a meter stick moving > wrt an SR observer is shorter than the light path length of the stay > at home meter stick. Why? Because light generated at the front end of > the stick will reach the rear end of the stick sooner for a moving > meter stick (c+v) according to the stay at home SR observer. > 3. So according to the SR observer the light path length of a moving > meter stick is as follows: > L' = L_o/gamma. > 4. The above interpretation avoids all the paradoxes that arise due > to > the bogus interpretation that a moving meter stick is physically > contracted. > > However, the above interpretation is incomplete. Why? Because the > light path length of a meter stick moving wrt the observer may be > longer than the observer's meter stick. In that case the light path > length of such meter stick is calculated as follows: > L' = L_o(gamma) > This interpretation is included in a new theory of relativity called > Improved Relativity Theory (IRT). IRT includes SRT as subset. > However, > the equations of IRT are valid in all environments, including > gravity. > A complete description of IRT is available in the following link:http://www.modelmechanics.org/2008irt.dtg.pdf > > Ken Seto > > Reply to author Forward > > You must Sign in before you can post messages. > To post a message you must first join this group. > Please update your nickname on the subscription settings page before > posting. > You do not have the permission required to post. An atom never goes flat as it is round. Mitch Raemsch
From: Ste on 9 Feb 2010 01:03
On 8 Feb, 16:47, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 8, 7:29 am, Ste <ste_ro...(a)hotmail.com> wrote: > > > Minkowski spacetime is a *mathematical* explanation, not a physical > > one. > > What is interesting about this remark is that you consider physics to > be the study of the material world, and by "material" you mean to > include matter, the space in which matter resides, and all other > manner of things in the universe. Thus the nature of space appears to > be in the bailiwick of the physical explanations provided by physics, > and yet somehow the structure of that space is not physical but > mathematical to you. > > Does this not seem oxymoronic to you? No, because as I've said Minkowski space is a mathematical quantification of reality. In truth, there is no "x-axis" in physical reality - it's a framework we impose arbitrarily to enable mathematical analysis. That's not to disparage the role of maths, but what I'm saying is that ultimately the mathematical explanation has to appeal to physical reality. It is fairly easy to demonstrate the tenets of Euclidean space. If you give someone a supply of rulers, and tell them to describe a place by using the numbers on the rulers, then it becomes fairly obvious that you need rulers in 3 axes. You can then relate the physical proof to the mathematical proof, by explaining that "axes" are a framework of rulers laid down arbitrarily. And then, building on that, it becomes obvious that for *prediction*, you need another dimension, that describes not just where, but *when*, and this has its physical analogy not in the ruler, but in the clock, and it becomes possible to describe where something will be not just by reference to numbers on a ruler, *but when a certain number is visible on the clock* (or the sundial, or whatever). So you get to 4 dimensions merely by appealing to everyday concepts that even children are familiar with. |