Preferred Frame Theory indistinguishable from SR
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From: Edward Green on 8 Jul 2010 12:41 On Jul 8, 6:28 am, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: <...> > Physicists *DO* reject the generalized principle of relativity expressed > as the requirement of general covariance because it is physically vacuous.. Aha. That's exactly what I was trying to express when you asked me to elaborate. Just how long have "physicists" felt this way, and when did they start reading my Usenet posts? :-) :-) :-) (I had an argument along these lines with John Baez years ago. I noticed another argument that I had with him -- to the effect that force is momentum flux -- later surfaced as an outstanding revalation in his home pages).
From: Daryl McCullough on 8 Jul 2010 13:06 Edward Green says... > >On Jul 8, 6:28=A0am, stevendaryl3...(a)yahoo.com (Daryl McCullough) wrote: > ><...> > >> Physicists *DO* reject the generalized principle of relativity expressed >> as the requirement of general covariance because it is physically vacuous > >Aha. That's exactly what I was trying to express when you asked me to >elaborate. Just how long have "physicists" felt this way, and when did >they start reading my Usenet posts? :-) :-) :-) The position I'm quoting was in Misner, Thorne and Wheeler's "Gravitation", which is at least 30 years old. >(I had an argument along these lines with John Baez years ago. I think it must have been subtly different, because John certainly knows that every theory can be made generally covariant. There is a related property that *isn't* vacuous, that I mentioned, which is the lack of non-dynamic scalar, vector, or tensor fields. In GR, all fields are dynamic. Roughly speaking, the way to make an arbitrary theory generally covariant is to stick in extra fields to correct for whatever changes in the theory occur when you do a coordinate transformation. But in general, those extra fields are non-dynamic. So I would like to know exactly what the argument was with John. >I noticed another argument that I had with him -- to the effect >that force is momentum flux -- later surfaced as an outstanding >revalation in his home pages). I'm not sure about that one. -- Daryl McCullough Ithaca, NY
From: PD on 8 Jul 2010 18:09 On Jul 7, 5:43 pm, colp <c...(a)solder.ath.cx> wrote: > On Jul 7, 8:52 am, PD <thedraperfam...(a)gmail.com> wrote: > > > On Jul 6, 3:03 pm, colp <c...(a)solder.ath.cx> wrote: > > > > On Jul 7, 3:07 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > The problem, you see, is that the comic-book statement you are using > > > > as your launching point belongs in COLP's Oversimplified Relativity.. > > > > It's not a comic book statement any more than Einstein's statement > > > that a moving clock lags behind a stationary clock is a comic book > > > statement. > > > Not so. Einstein's statement included things that you have discounted. > > I haven't discounted them. > > > For example, he makes note of specific events, rather than just making > > the general statement that "moving clocks" run slow. > > The description of the specific events only serves to illustrate that > it is the moving clock that runs slow compared to the stationary > clock. Then you have misunderstood what he said. The EVENTS do more than that. > > > Furthermore, he > > makes EXPLICIT mention of the statement that the clocks at points A > > and B are initially synchronized IN THE K FRAME. > > Assuming that they weren't synchonized in my general description of > "the moving clock runs slow" would be arbitrary and illogical. They are synchronized in the K frame. They are not synchronized in the K' frame. This is essential and cannot be dismissed. > Remember I was talking about _the_ clock, in reference to the moving > clock described in "Electrodynamics of Moving Bodies", not to a clock > in an arbitrary system. I understand that completely. There are two clocks involved here: One that moves from A to B and one that remains at B. There is a frame K in which points A and B are at rest, and there is a frame K' in which points A and B are moving and the first clock above is at rest. > > > A contradiction would > > arise by making the clock at B the moving clock only if the clocks are > > claimed to be intially synchronized also in the K' frame -- but they > > are NOT, and this is the essential detail that you have missed. > > No, it isn't a missing detail, it is an implication of Einstein's > first postulate of relativity. WHAT is an implication of the first postulate? That they are also synchronized in K'? No. > > Here is Einstein's description of the clocks: > > "If at the points A and B of K there are stationary clocks which, > viewed in the stationary system, are synchronous; and if the clock at > A is moved with the velocity v along the line AB to B, then on its > arrival at B the two clocks no longer synchronize, but the clock moved > from A to B lags behind the other which has remained at B ..." > > Let us call the moving system K', in which the moving clocks at A' and > B' are synchronized for an observer in K'. The stationary system K > also has two clocks, but these two clocks are synchronized for an > observer in K. Frames K and K' move at a constant velocity with > respect to each other. > > If there is no preferred frame of reference then there is no reason > why the clocks at A' and B' cannot also be synchronized for an > observer in K', just as the clocks at A and B are for an observer in > K, due to the symmetry of the two frames and their respective clocks. Yes, that is true but the clock that is synchronized with B in K will not initially show the same time as the clock that is synchronized with B in K'. Now YOU are the one that is adding things beyond what Einstein actually said. There are only TWO clocks in Einstein's paragraph. One that moves from A to B and one that remains at B. In the frame K, the clocks are synchronized when the clocks are at A and B. In the frame K' that you propose, those same two clocks are not synchronized when the clocks are at A and B. In BOTH frames, when the clocks are next to each other at B, the two clocks will show different times. To give you a numerical example, A and B and the velocity of one clock from A to B can be arranged such that the following is true: In the frame K, where A and B are stationary: Clock at A and clock at B both read 1:23:05 at the same moment (simultaneously). They are synchronized. When clock from A arrives at B, it reads 1:23:11. The clock that remained at B reads 1:23:14. Now, in the frame K', where A and B are moving: Clock at rest reads 1:23:05 when A sweeps over it. The clock that is at B reads 1:23:10 at this instant (simultaneously). They are not synchronized. When point B sweeps over the clock at rest, it reads 1:23:11. The clock that moved along with B reads 1:23:14. You can see plainly that in the K frame, the moving clock runs slower than the stationary clock, because 6 seconds have elapsed on clock crossing A and B, and 9 seconds have elapsed on clock staying at B. And when the two clocks are adjacent, clock crossing A and B is behind clock staying at B by 3 seconds. You can also see that in the K' frame, the moving clock runs slower than the stationary clock, because 4 seconds have elapsed on clock staying at B and 6 seconds have elapsed on the clock that A and B sweep over. And when the two clocks are adjacent, clock crossing A and B is behind clock staying at B by 3 seconds. So, you see, there is nothing contradictory in SR about this situation. In either K or K', the moving clock runs more slowly than the stationary clock. In either frame, the difference between the two clocks is identical when the two clocks are together. PD
From: colp on 8 Jul 2010 21:59 On Jul 9, 10:09 am, PD <thedraperfam...(a)gmail.com> wrote: > On Jul 7, 5:43 pm, colp <c...(a)solder.ath.cx> wrote: > > > > > On Jul 7, 8:52 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Jul 6, 3:03 pm, colp <c...(a)solder.ath.cx> wrote: > > > > > On Jul 7, 3:07 am, PD <thedraperfam...(a)gmail.com> wrote: > > > > > The problem, you see, is that the comic-book statement you are using > > > > > as your launching point belongs in COLP's Oversimplified Relativity. > > > > > It's not a comic book statement any more than Einstein's statement > > > > that a moving clock lags behind a stationary clock is a comic book > > > > statement. > > > > Not so. Einstein's statement included things that you have discounted.. > > > I haven't discounted them. > > > > For example, he makes note of specific events, rather than just making > > > the general statement that "moving clocks" run slow. > > > The description of the specific events only serves to illustrate that > > it is the moving clock that runs slow compared to the stationary > > clock. > > Then you have misunderstood what he said. The EVENTS do more than > that. How, exactly? > > > > > > Furthermore, he > > > makes EXPLICIT mention of the statement that the clocks at points A > > > and B are initially synchronized IN THE K FRAME. > > > Assuming that they weren't synchonized in my general description of > > "the moving clock runs slow" would be arbitrary and illogical. > > They are synchronized in the K frame. They are not synchronized in the > K' frame. This is essential and cannot be dismissed. If they are not synchronized in the K' frame, then the K frame becomes the preferred frame of reference, which contradicts Einstein's first postulate. > > > Remember I was talking about _the_ clock, in reference to the moving > > clock described in "Electrodynamics of Moving Bodies", not to a clock > > in an arbitrary system. > > I understand that completely. There are two clocks involved here: One > that moves from A to B and one that remains at B. There is a frame K > in which points A and B are at rest, and there is a frame K' in which > points A and B are moving and the first clock above is at rest. Yes, I agree. > > > > > > A contradiction would > > > arise by making the clock at B the moving clock only if the clocks are > > > claimed to be intially synchronized also in the K' frame -- but they > > > are NOT, and this is the essential detail that you have missed. > > > No, it isn't a missing detail, it is an implication of Einstein's > > first postulate of relativity. > > WHAT is an implication of the first postulate? That they are also > synchronized in K'? No. The implication is that if there is no preferred frame of reference then predictions made in one inertial frame will be just as valid as predictions made in any other inertial frame, and if it is possible to synchronize clocks in one inertial frame them it is possible to synchronize clocks in any other inertial frame. > > > > > > > Here is Einstein's description of the clocks: > > > "If at the points A and B of K there are stationary clocks which, > > viewed in the stationary system, are synchronous; and if the clock at > > A is moved with the velocity v along the line AB to B, then on its > > arrival at B the two clocks no longer synchronize, but the clock moved > > from A to B lags behind the other which has remained at B ..." > > > Let us call the moving system K', in which the moving clocks at A' and > > B' are synchronized for an observer in K'. The stationary system K > > also has two clocks, but these two clocks are synchronized for an > > observer in K. Frames K and K' move at a constant velocity with > > respect to each other. > > > If there is no preferred frame of reference then there is no reason > > why the clocks at A' and B' cannot also be synchronized for an > > observer in K', just as the clocks at A and B are for an observer in > > K, due to the symmetry of the two frames and their respective clocks. > > Yes, that is true but the clock that is synchronized with B in K will > not initially show the same time as the clock that is synchronized > with B in K'. Are you saying that the clock at A in K (that is synchronized with the clock at B in K) will not initially show the same time as the clock at A' in K' (that is synchronized with the clock at B' in K'? > > Now YOU are the one that is adding things beyond what Einstein > actually said. What I am adding (two more clocks in K') does not change Einstein's postulates. Neither does making predictions from the point of view of an observer in each frame affect the postulates. > > There are only TWO clocks in Einstein's paragraph. One that moves from > A to B and one that remains at B. In the frame K, the clocks are > synchronized when the clocks are at A and B. Right. > In the frame K' that you > propose, those same two clocks are not synchronized when the clocks > are at A and B. I'm not talking about the same two clocks. I'm talking about two frames which are the same in all respects except for their relative motion (in order to establish symmetry). Thus in the K frame the clock at A' moves from A to B. When point A = point A', the clocks at these points are synchronized, just as Einstein's clock at A was synchronized with B before it moved towards B. Looking at the situation from the point of view of an observer in K', the clock at B moves from B' to A'.
From: Koobee Wublee on 9 Jul 2010 01:43
On Jul 8, 10:04 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Wilson and Penzias discovered the CMBR in the 1960s; Lorentz died in 1928. That is indeed history. <shrug> > The CMBR has a rich and varied multipole structure, as any good reference on it > will show. There are maps of CMBR temperature in all directions, and they have > LOTS of structure; Playing down the insignificance of the dipole of CMBR due to it leading to non-politically conclusions. <shrug> > ironically, they are invariably displayed in the dipole=0 > frame (because otherwise the dipole would obscure the structure because the > dipole is by far the largest multipole present). But still cannot ignore this experimental result. <shrug> > Selecting the frame in which > its dipole moment is zero cannot cancel all the other multipoles, and thus it is > not isotropic in that frame. In another words, the Doppler shift in CMBR is indeed very significant. It hints at unveiling the absolute frame of reference as predicted by the MMX. <shrug> The team that discovered this Doppler dipole in CMBR should be awarded with the Nobel Prize. <shrug> |