A constant speed of light in all reference frames? Surely you can't be serious.
in [Relativity]
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From: Peter Webb on 16 Feb 2010 02:16 "mpc755" <mpc755(a)gmail.com> wrote in message news:17353969-96de-46d5-b54c-74e655e2d34f(a)b7g2000yqd.googlegroups.com... On Feb 16, 12:59 am, "Peter Webb" <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > "mpc755" <mpc...(a)gmail.com> wrote in message > > news:48499780-10ed-4377-b4cf-0bde5b5d298f(a)28g2000vbf.googlegroups.com... > On Feb 15, 1:06 am, "Peter Webb" > > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > "mpc755" <mpc...(a)gmail.com> wrote in message > > >news:21c1d72e-9898-436a-ba4e-05a849fc4efc(a)g8g2000pri.googlegroups.com... > > On Feb 15, 12:35 am, "Peter Webb" > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > > "mpc755" <mpc...(a)gmail.com> wrote in message > > > >news:e03b248e-5f49-4e80-9c4c-d542dd7e269e(a)k5g2000pra.googlegroups.com... > > > On Feb 15, 12:18 am, "Peter Webb" > > > > <webbfam...(a)DIESPAMDIEoptusnet.com.au> wrote: > > > > As I have said at least three times now, > > > > you cannot determine the speed of the aether. > > > > ____________________________________ > > > > > You said light moves at a constant velocity relative to the ether. > > > > So > > > > why > > > > can't you measure the speed of light, see how much it differs from > > > > c, > > > > and > > > > the difference is your speed relative to the ether? Why doesn't that > > > > procedure determine the speed of the ether? > > > > How do you measure your speed relative to the ether? > > > > As I have said at least four times now, you can't measure the speed of > > > the aether. If you can't measure the speed of the aether you can't > > > measure your speed relative to the aether. > > > > Do you want to ask this same question again so I can answer it for a > > > fifth time? > > > > ______________________________________ > > > I just described how you *can* measure your speed relative to the > > > ether. > > > You > > > measure the speed of light, see how much it differs from c, and the > > > difference is your speed relative to the ether. > > > How do you measure the speed of light so it is not 'c'? > > > _________________________________ > > Anyway you like. Aren't you claiming that the speed of light is a > > constant > > relative to the speed of the ether, and not constant relative to the > > observer? So you can measure the speed of light in some way, to make > > this > > claim at all, right? So why not measure it, see how much it departs from > > c, > > and then the difference is the speed of the ether. > > > Why won't that work? > > I am asking you to state how it is you want to measure the speed of > light? Are you using mirrors? > > ____________________ > No. I am using a metre ruler and two clocks, one at each end. I > synchronise > the clocks, separate them by a metre, and note the difference between > arrival and departure time. The difference between this and c is my speed > relative to the ether. Why won't this work? You separate the clocks by a metre on a train moving relative to the aether. <snip about 200 lines involving trains, embankments and whole lot of other stuff unrelated to my question> ____________________________________ No. There is no train in my question. There are two clocks and a one metre ruler. They are on a tabletop. Both clocks are together at the middle. They are very slowly moved to opposite ends of thje 1 metre ruler - take a year if you like. A photon is sent from opne to the other, and the difference in time gives you the speed c' with which the light travelled. Note that two clocks can be brought back together again and they are still synchronised. If light moves at speed c relative to the ether, and c' relative to you, then your speed relative to the ether must be the difference c-c'. This would appear to give a mechanism to exactly measure your speed relative to the ether. Does it? If not, why not?
From: funkenstein on 16 Feb 2010 06:28 On Feb 13, 2:29 pm, Ste <ste_ro...(a)hotmail.com> wrote: > I've been absolutely racking my brain (to the point of getting a > headache) for the last few days about this issue, and it's clear that > the speed of light (where light is either considered in the form of a > ballistic photon, or a wave-cycle) cannot, physically, be constant in > all relative frames, and at the same time be constant when travelling > between two objects in two different frames. It's a physical and > logical impossibility. > > It's also clear that velocities cannot be additive (in the form of > speed of bullet+speed of gun), and nor can they be subtractive > relative to a background medium (in the form of speed of propagation > in medium-speed of source). > > Take an illustration: > > A C > B > > Where A and B are atoms that pass infinitely close to each other. In > the illustration, A and B are separated from C by a distance L. A and > C are stationary relative to each other. B is moving, and approaching > C at a speed S. A pulse is emitted from both A and B simultaneously > towards C, at the point when A and B are equidistant from C. > > Now, clearly, if velocities were additive, then light from B would > reach C much quicker than light from A. We don't see that, so we can > dismiss that immediately. > > Next, if velocities were subtractive, like sound, well that seems like > a compelling explanation for what we see, which is that light from > both A and B travel towards C at the same speed. But the presence of > an absolute medium seems to fall down when one considers that, to be > consistent with observation, the speed of propagation orthogonal to > the direction of travel must be the same as the speed in the direction > of travel. > > A speed (i.e. a mesure of distance traversed within a period of time) > cannot possibly be measured constant in all directions within a frame, > *and* constant between frames, where the frames themselves are moving > at a speed relative to each other. So how the hell does one reconcile > this physically? Hi Ste, Maybe this will help to reconcile physically. What do we mean by distance? A meter stick is a collection of atoms held together by the electromagnetic forces. What we think of as "distance" is our observation of electromagnetic effects. A moving observer has no choice but to use electromagnetism, i.e. a constant speed of light, to define his metric. The speed of light as an invariant constant in any reference frame is just a result of our choice of metric. Hope this helps- cheers
From: JT on 16 Feb 2010 06:41 On 16 Feb, 12:28, funkenstein <luke.s...(a)gmail.com> wrote: > On Feb 13, 2:29 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > > > > > I've been absolutely racking my brain (to the point of getting a > > headache) for the last few days about this issue, and it's clear that > > the speed of light (where light is either considered in the form of a > > ballistic photon, or a wave-cycle) cannot, physically, be constant in > > all relative frames, and at the same time be constant when travelling > > between two objects in two different frames. It's a physical and > > logical impossibility. > > > It's also clear that velocities cannot be additive (in the form of > > speed of bullet+speed of gun), and nor can they be subtractive > > relative to a background medium (in the form of speed of propagation > > in medium-speed of source). > > > Take an illustration: > > > A C > > B > > > Where A and B are atoms that pass infinitely close to each other. In > > the illustration, A and B are separated from C by a distance L. A and > > C are stationary relative to each other. B is moving, and approaching > > C at a speed S. A pulse is emitted from both A and B simultaneously > > towards C, at the point when A and B are equidistant from C. > > > Now, clearly, if velocities were additive, then light from B would > > reach C much quicker than light from A. We don't see that, so we can > > dismiss that immediately. > > > Next, if velocities were subtractive, like sound, well that seems like > > a compelling explanation for what we see, which is that light from > > both A and B travel towards C at the same speed. But the presence of > > an absolute medium seems to fall down when one considers that, to be > > consistent with observation, the speed of propagation orthogonal to > > the direction of travel must be the same as the speed in the direction > > of travel. > > > A speed (i.e. a mesure of distance traversed within a period of time) > > cannot possibly be measured constant in all directions within a frame, > > *and* constant between frames, where the frames themselves are moving > > at a speed relative to each other. So how the hell does one reconcile > > this physically? > > Hi Ste, > > Maybe this will help to reconcile physically. > What do we mean by distance? > > A meter stick is a collection of atoms held together by the > electromagnetic forces. > What we think of as "distance" is our observation of electromagnetic > effects. > > A moving observer has no choice but to use electromagnetism, i.e. a > constant speed of light, to define his metric. > > The speed of light as an invariant constant in any reference frame > is just a result of our choice of metric. > > Hope this helps- cheers- Dölj citerad text - > > - Visa citerad text - Idiot a distance is the spatial separation between two points, a length is the spatial extension of an object, a unit is a comparisson tool, a length *unit* should be a spatial comparisson tool. A meter as defined by modern physics is a circular definition an ECDT. JT
From: Androcles on 16 Feb 2010 06:58 "funkenstein" <luke.saul(a)gmail.com> wrote in message news:8a868e1a-bae9-4e8c-b087-621496d9b7d8(a)w31g2000yqk.googlegroups.com... On Feb 13, 2:29 pm, Ste <ste_ro...(a)hotmail.com> wrote: > I've been absolutely racking my brain (to the point of getting a > headache) for the last few days about this issue, and it's clear that > the speed of light (where light is either considered in the form of a > ballistic photon, or a wave-cycle) cannot, physically, be constant in > all relative frames, and at the same time be constant when travelling > between two objects in two different frames. It's a physical and > logical impossibility. > > It's also clear that velocities cannot be additive (in the form of > speed of bullet+speed of gun), and nor can they be subtractive > relative to a background medium (in the form of speed of propagation > in medium-speed of source). > > Take an illustration: > > A C > B > > Where A and B are atoms that pass infinitely close to each other. In > the illustration, A and B are separated from C by a distance L. A and > C are stationary relative to each other. B is moving, and approaching > C at a speed S. A pulse is emitted from both A and B simultaneously > towards C, at the point when A and B are equidistant from C. > > Now, clearly, if velocities were additive, then light from B would > reach C much quicker than light from A. We don't see that, so we can > dismiss that immediately. > > Next, if velocities were subtractive, like sound, well that seems like > a compelling explanation for what we see, which is that light from > both A and B travel towards C at the same speed. But the presence of > an absolute medium seems to fall down when one considers that, to be > consistent with observation, the speed of propagation orthogonal to > the direction of travel must be the same as the speed in the direction > of travel. > > A speed (i.e. a mesure of distance traversed within a period of time) > cannot possibly be measured constant in all directions within a frame, > *and* constant between frames, where the frames themselves are moving > at a speed relative to each other. So how the hell does one reconcile > this physically? Hi Ste, Maybe this will help to reconcile physically. What do we mean by distance? A meter stick is a collection of atoms held together by the electromagnetic forces. What we think of as "distance" is our observation of electromagnetic effects. A moving observer has no choice but to use electromagnetism, i.e. a constant speed of light, to define his metric. The speed of light as an invariant constant in any reference frame is just a result of our choice of metric. Hope this helps- cheers ================================================ Not my choice, and your choice is fuckin' stupid. Hope that helps, but I doubt it will.
From: Ste on 16 Feb 2010 07:21
On 16 Feb, 01:18, PD <thedraperfam...(a)gmail.com> wrote: > On Feb 15, 6:14 pm, Ste <ste_ro...(a)hotmail.com> wrote: > > > No I actually agree with you Paul. The use of the word "rotation" is > > perfectly legitimate in this context, to describe a geometric > > transformation. My argument is that those who claim knowledge here > > don't seem to emphasise strongly enough, when queried, that this > > geometric rotation into time bears *absolutely no resemblance at all* > > to the physical act of spatial rotation. > > Well, that would be also going too far. The spatial rotation is a > special case of the general rotation, after all, so they can't be > *completely* different things. Mathematically, you're correct, spatial rotation is a special case of general rotation. Physically, you're not in any way correct. A rotation in any of the 3 spatial dimensions bears no sensory correspondence at all to this alleged "rotation in time". > To continue pounding on my analogy, it is incorrect to say that whales > bear *absolutely no resemblance at all* to tetrapod land mammals. They > bear a *strong* resemblance on the issues that pertain to being a > mammal. > > But I understand your plea. You feel it is the burden of the expert to > be sure that the novice does not misconstrue, which includes actively > forestalling all places where they may make an erroneous assumption. I > can see why this might be expected as part of a teaching arrangement, > in a teaching venue, where the participants have clear teacher and > student roles. But in an informal discussion group, it's less clear > where the burden lies, you see. I dare say the burden is simply on the expert to either speak a common language, or to specify which parts of his vocabulary are not common. After all, the expert, as someone who has contact with both the common and the specialised vocabulary, is the only person who is ever going to be in a position to know where those vocabularies differ. I also tend to take the view that discussion is often good for the expert's understanding. > > If > > something has both behaviours, then that's something that modern > > physics needs to explain coherently. > > Why? It's a class of objects that is discovered in nature and the > behaviors are *observed*. Why do we have to explain WHY our > pigeonholing doesn't work for them, other than to acknowledge there is > something wrong with our pigeonholing scheme? > > After all, viruses do not meet the usual criteria of "living things", > nor do they meet the usual criteria of "nonliving things". They have > *some* of the properties of both. Does this mean that we have to > explain why viruses can exist, because they resist our pigeonholing? I think your misunderstanding. A new pigeonhole can be specified, but it still requires a specification. It's not good enough to simply say "this is what we observe" and shrug, because that tells you nothing about the underlying variables or how the phenomenon works. |