colp, why did AE use the word "relativity"?
in [Relativity]
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From: PD on 23 Jun 2010 12:37 On Jun 23, 11:28 am, colp <c...(a)solder.ath.cx> wrote: > > In the symmetric twin paradox, SR predicts that each twin will see the > other's clock run slow, but it must be seen to run fast in order to > that the twin's clocks read the same time at the end of the experiment > and avoid the paradox. > No, SR does NOT say that. It is precisely the purpose of this kind of puzzle to ERADICATE oversimplifications about SR that students often hold in their heads, like "SR predicts each twin will see the other's clock run slow". What puzzles like this are intended to do are to get you to say, "OK, well, following what I *thought* relativity says leads to a contradiction, so I must not fully understand what relativity says. What does relativity really say beyond what I've heard about it?" For some people though, the notion of accepting that their understanding is shallow and superficial to the point where it leads to obvious contradictions is unpalatable, and so they instead will insist that their understanding is just fine and it's the theory that's full of holes. This is egotism of the highest order. PD
From: colp on 23 Jun 2010 12:42 On Jun 24, 4:21 am, PD <thedraperfam...(a)gmail.com> wrote: > There are no experimental results that would support the aether theory > over relativity, despite attempts to search for them. Evidence of something is not limited to direct physical observations - a logical argument based of knowledge of the physical world is a form of evidence. An argument which supports that theory is the symmetric twin paradox can be avoided by positing the existence of a preferred frame of reference, which is a concept similar to that of the aether. The usual argument against the twin paradox is that frame-jumping is an error, but frame jumping is not prohibited by the premises of SR. > > There are experimental results other than the Michelson Morley > experiment that rule out an aether strongly entrained by the Earth. Please elaborate.
From: colp on 23 Jun 2010 12:47 On Jun 24, 4:37 am, PD <thedraperfam...(a)gmail.com> wrote: > On Jun 23, 11:28 am, colp <c...(a)solder.ath.cx> wrote: > > > > > In the symmetric twin paradox, SR predicts that each twin will see the > > other's clock run slow, but it must be seen to run fast in order to > > that the twin's clocks read the same time at the end of the experiment > > and avoid the paradox. > > No, SR does NOT say that. (copied from a previous post) In the symmetric twin paradox, SR predicts that each twin will see the other's clock run slow, but it must be seen to run fast in order to that the twin's clocks read the same time at the end of the experiment and avoid the paradox. The premises of SR specify observed time dilation, never time compression, so the paradox cannot be avoided. <quote> 2. An ideal clock traveling at speed v for time period t will show an elapsed time of T = t square-root(1-(v/c)^2). </quote>
From: PD on 23 Jun 2010 15:32 On Jun 23, 11:42 am, colp <c...(a)solder.ath.cx> wrote: > On Jun 24, 4:21 am, PD <thedraperfam...(a)gmail.com> wrote: > > > There are no experimental results that would support the aether theory > > over relativity, despite attempts to search for them. > > Evidence of something is not limited to direct physical observations - > a logical argument based of knowledge of the physical world is a form > of evidence. > > An argument which supports that theory is the symmetric twin paradox > can be avoided by positing the existence of a preferred frame of > reference, which is a concept similar to that of the aether. > > The usual argument against the twin paradox is that frame-jumping is > an error, but frame jumping is not prohibited by the premises of SR. > A couple of comments: - Your statement that a logical argument based on common experience of the physical world is evidence FOR a model is not really scientifically sound. Common experience is the practice of taking an approximate rule that applies well in a good set of everyday circumstances and then extending it to be general rule. This is fraught with peril, though it has worked well as an evolutionarily advantageous strategy for human survival. When models compete, the usual scientific approach is to find out where they DISAGREE in a prediction about a measurable observation, and then go and measure nature's behavior under those circumstances. This way, there is no ambiguity -- the measured result will simply agree with model A and disagree with model B. It doesn't make any difference whatsoever whether model B is more plausible or appealing to common sense. - Your contention is that an aether avoids having to absorb a paradox. The problem is, there is no paradox in special relativity's account of what happens with symmetric twins. There is a paradox present in *your* mental idea of what relativity says, which I will call "COLPs Oversimplified Relativity", but there is no paradox in relativity. So what you are saying is that Colp's Oversimplified Relativity has a problem that is alleviated by proposing an aether, but this has no bearing whatsoever on the fact that special relativity has no problem of the sort you're worried about. It certainly makes sense on the basis of the paradox to drop Colp's Oversimplified Relativity in favor of an aether model, but it makes no sense to drop special relativity in favor of an aether model. > > > > There are experimental results other than the Michelson Morley > > experiment that rule out an aether strongly entrained by the Earth. > > Please elaborate. There are quite a number. You could look up the Hammar experiment, which was specifically designed to be sensitive to aether-dragging at the Earth's surface. However, the definitive nail in the coffin appears to be stellar aberration, a measurable phenomenon which would be dramatically different if there were aether entrainment by the Earth. Essentially, it would be easy to identify bending that would be due to the transition from interstellar aether to entrained aether, for the light that traverses both regions (from stars to Earth's surface). The lesson to be learned here is that no one experiment ever serves to single out one theory above all others. It takes a *collection* of experimental results to rule out other candidates. Any given experiment may be compatible with one or more competing models, but different experiments rule out different sets of theories, and the one that survives all the tests is the scientific winner. PD
From: PD on 23 Jun 2010 15:34
On Jun 23, 11:47 am, colp <c...(a)solder.ath.cx> wrote: > On Jun 24, 4:37 am, PD <thedraperfam...(a)gmail.com> wrote: > > > On Jun 23, 11:28 am, colp <c...(a)solder.ath.cx> wrote: > > > > In the symmetric twin paradox, SR predicts that each twin will see the > > > other's clock run slow, but it must be seen to run fast in order to > > > that the twin's clocks read the same time at the end of the experiment > > > and avoid the paradox. > > > No, SR does NOT say that. > > (copied from a previous post) > > In the symmetric twin paradox, SR predicts that each twin will see the > other's clock run slow, but it must be seen to run fast in order to > that the twin's clocks read the same time at the end of the experiment > and avoid the paradox. > > The premises of SR specify observed time dilation, never time > compression, so the paradox cannot be avoided. > > <quote> > 2. An ideal clock traveling at speed v for time period t will show an > elapsed time of T = t square-root(1-(v/c)^2). > </quote> I'm not sure what you're quoting. It may be a simplified presentation of relativity intended for beginners or laypeople. A physicist would look at the above statement and say, "Well, that's an awfully uncareful sentence which could lead to confusion." |