Notion of Absolute Clock Synchronization in SR
in [Relativity]
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From: Inertial on 19 Mar 2010 20:12 "GSS" <gurcharn_sandhu(a)yahoo.com> wrote in message news:0e88c2df-45b1-45b0-95ab-6a1e8447c7b5(a)z3g2000yqz.googlegroups.com... > On Mar 19, 6:12 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "GSS" <gurcharn_san...(a)yahoo.com> wrote in message >> > ..... >> >>> Let us consider two identical precision atomic clocks, positioned at >>> points A and B, separated by a distance of about 30 km along east- >>> west direction, on the surface of earth. >> >> As you are talking SR, you must be assuming that the surface of the earth >> is >> an inertial frame (so we'll ignore it rotating, or orbitting, and ignore >> gravity). >> > No, I meant to ignore gravity effects only. > >>> Assume the two clocks A and B >>> are mutually synchronized through Einstein convention such that the >>> time taken, T_ab, by a laser pulse to propagate from A to B (as >>> measured from the clock readings of B and A) is the same as the time >>> taken, T_ba, by a laser pulse to propagate from B to A. >> >> Which is, of course, obviously true. >> >>> That means, >>> T_ab - T_ba = 0 which indicates e-synchronization of the two clocks. >> >> Only if that is what the clocks show. The fact light takes the same time >> to >> travel the same distance at the same speed doesn't make the clocks >> synchronized. >> >>> In your opinion, will this synchronization remain valid at least for a >>> 24 hour period? That is, if we take to and fro signal propagation time >>> readings at hourly intervals, will all readings show, >>> T_ab - T_ba = 0 >> >> It will be valid forever, if they remain at rest in the inertial frame. >> > Will it still be valid for ever, if they remain at rest only in the > local or lab frame fixed on the surface of earth? What do you think is > the effect of earth rotation on the mutual e-synchronization of two > clocks in the lab frame? I was explicitly ignoring such effects and treating the frame as inertial. But as one assumes both clocks undergo the same velocity profiles, they should remain in sync > >>> Perhaps you may like to call this mutual synchronization of clocks A >>> and B as the 'local clock synchronization' valid in the local or lab >>> frame of the two clocks. >> >> If you want to. >> >>> Kindly explain the procedure for e-synchronization of the same two >>> atomic clocks A and B in the ECI or the GCRF frame. How exactly will >>> it be different from the local clock synchronization in practical >>> terms? >> >> The clocks would have to be at rest in those frames. >> >> If not, then you can of course have a whole series of appropriate clocks >> that ARE at rest in the frame you want (so A and B will be comoving past >> those clocks), and chose a time on those clocks (say 12:00), and >> whichever >> rest clocks A and B are adjacent to when those rest get to 12:00, copy >> that >> time to A and B. Then A and B will be in sync in that frame, and show >> the >> same time in that frame. But they won't be measured as ticking at the >> correct rate, so they will get more and more out of synch with other rest >> clocks they pass. > > I don't think you really mean what you write. Yes I do > Do you seriously think there are some atomic clocks that are actually > at rest in the ECI or BCRF frames? I don't know the locations and movements of all atomic clocks. > Or can you ever make any atomic > clock ever at rest in the ECI or BCRF frames? Of course you can >>> Since the two clocks under consideration are simultaneously known to >>> be co-moving in the solar system at about 30 km/s, you may kindly >>> explain the procedure for e-synchronization of the same two atomic >>> clocks A and B in the solar system BCRF frame. >> >> The clocks would have to be at rest in that frame. (Or see above) >> > But how? By having a zero velocity in that frame .. what a stupid question >>> How exactly will it be >>> different from the local clock synchronization in practical terms? >> >> No different at all. But the same clocks are not going to be both at >> rest >> in more than one (non-eqivalent) inertial frame. >> >>> Going one step still further,the two clocks under consideration are >>> simultaneously known to be co-moving in the Galactic reference frame >>> at about 200 km/s. Kindly explain the procedure for e-synchronization >>> of the same two atomic clocks A and B in the Galactic reference frame. >> >> The clocks would have to be at rest in that frame. (Or see above) >> > What I make out from your response is that two clocks A and B > considered above, can be e-synchronized in ECI or BCRf or Galactic > reference frames only if these clocks can be brought to rest in these > frames. Only if they ARE at rest in that frame when you sync them. If you subsequently accelerate them, that will change their ticking rates > Since it is practically impossible to bring the two clocks (at > rest on the surface of earth) Who said they have to be at rest on the surface of the earth? > to rest in ECI or BCRF or Galactic > reference frames, They can't be at rest in those different frames at the same time > it implies that it is practically impossible to > mutually e-synchronize the two clocks in any of these inertial > reference frames. Unless you calculate what the time should be. But you cannot do it via e-synch method alone. > That means two atomic clocks A and B can be mutually > e-synchronized only in their local or lab frame and none else. Of course .. synch is frame dependent. Didn't you know that? If they are in sync in one frame, they are not in sync in another. ie if you have two clocks (A and B) in sync in one frame pass adjacent to another two clocks (A' and B') that are in sync in another frame (ignoring trivial cases like the clocks being colocated etc), then you CANNOT have the same time shown on both corresponding clocks (ie cannot have A = A' and B = B') > All > talk of e-synchronizing two or more atomic clocks in different > inertial reference frames in relative uniform motion, is just > hypothetical day dreaming or gedanken. It is impossible for them to be mutually at sync. > Do other relativity experts agree? Of course they would
From: harald on 20 Mar 2010 08:15 On Mar 19, 5:39 pm, va...(a)icmf.inf.cu wrote: > On 19 mar, 04:23, harald <h...(a)swissonline.ch> wrote: > > > On Mar 18, 11:27 pm, va...(a)icmf.inf.cu wrote: > > > > On 18 mar, 10:49, harald <h...(a)swissonline.ch> wrote: > > > > > On Mar 18, 3:04 pm, va...(a)icmf.inf.cu wrote: > > > > > > On 17 mar, 10:34, harald <h...(a)swissonline.ch> wrote: > > > > > > > On Mar 17, 3:34 pm, va...(a)icmf.inf.cu wrote: > > > > > > > > On 16 mar, 17:20, harald <h...(a)swissonline.ch> wrote: > > > > > > > > > On Mar 16, 3:30 pm, va...(a)icmf.inf.cu wrote: > > > > > > > > > > On 15 mar, 05:53, harald <h...(a)swissonline.ch> wrote: > > > > > [..] > > > > > > > > > > > > E-sync means that the ELAPSED times of both clocks correspond, as well as > > > > > > > > > > > the readings at some time. E-sync'd clocks remain in synch. > > > > > > > > > > > Thanks for the elaboration. But more precisely: e-synched "perfect", > > > > > > > > > > "stationary" clocks remain in sync (if at the same gravitational > > > > > > > > > > potential). Now, let's hope that the OP will understand this. :) > > > > > > > > > > (Hello Harald, nice to meet you again). > > > > > > > > > In the ECI frame of GPS all the clocks remain synchronized, even if > > > > > > > > > they have different velocities and gravitational potentials. Then, > > > > > > > > > taking into account that huge experimental evidence, I dont see any > > > > > > > > > other alternative that to accept that absolute clock synchronization > > > > > > > > > exists in SR with the following meaning. Once perfect and stationary > > > > > > > > > clocks are e-synchronized in some inertial frame, they remain showing > > > > > > > > > the same time lecture at any local instant in all the others inertial > > > > > > > > > frames. Of course, that equal time lecture does not correspond to > > > > > > > > > the local time in each of the others inertial frames, where according > > > > > > > > > to SR rules, the now moving clocks (all with the same velocity) are > > > > > > > > > running slower than the local perfect and stationary e-synchronised > > > > > > > > > ones. > > > > > > > > > > RVHG (Rafael Valls Hidalgo-Gato) > > > > > [..] > > > > > > > The topic of this thread is concerned with the fact that according to > > > > > > all inertial reference systems in which the inertial reference system > > > > > > with its synchronized clocks is moving, those clocks are out of sync > > > > > > with each other (see also below). > > > > > > > > I mentioned the ECI of GPS, taken for granted that the e- > > > > > > > synchronization method of all its clocks is well-known. Let us > > > > > > > remember that all the moving clocks show the unique ECI time, > > > > > > > corresponding to the same time that a similar clock at rest in the > > > > > > > relevant ECI point would show. If now we consider the ECI moving at a > > > > > > > constant velocity with respect to an (imaginary) inertial frame B, > > > > > > > Note: the ECI "frame" itself is already an imaginary frame... > > > > > > I dont understand why you consider the ECI an imaginary frame. > > > > > The whole Earth is rotating relative to it; there isn't any material > > > > frame that is pretended to be "in rest". > > > > I have a doubt here about what do you mean by material frame. > > > A stiff thing made up of atoms (such as earth, wood, steel or > > concrete). > > > [..] > > > > > > Yes, an inertial observer at rest in the moving system (moving GPS > > > > > satellite) appreciates all ECI clocks out of synchronism, but who > > > > > care that? > > > > > OK, perhaps I misunderstood what you tried to communicate - in which > > > > case I don't know what it was! > > > > I prefer to put the emphasis in what we are in agreement now. Our own > > > ideas can be evolving somewhat in the time. > > > > > In fact, you here agree with the SRT claim that clock synchronisation > > > > (along x) is "relative", in the sense that it is meant. > > > > Yes, without any doubt synchronization is relative to the inertial > > > frame you select to do it. But let us take some care here, I > > > distinguish a real inertial system (the centre of mass one associated > > > to some well-determined body set) from an imaginary one (as all of > > > them in the 1907 Minkowski view). > > > > > > I feel now very happy with your very valuable reference to 1905 > > > > > Einstein first paper on Relativity. Now we can make real the imaginary > > > > > inertial frame B identifying it with a moving GPS satellite (the real > > > > > inertial frame B is the centre of mass one corresponding to the > > > > > satellite and all bodies in its interior). > > > > > You can choose it as you wish, according to SRT (as long as it isn't > > > > rotating, which is incompatible with GPS satellites!). > > > > An inertial frame can never be rotating. The space belonging to the > > > ECI (or any other inertial frame) has always all its points at rest. > > > > > Consider now the inertial Solar System (the centre of mass one of all > > > > > its bodies). In principle, we can synchronize clocks in all its > > > > > planets, showing all of them the same unique time defined by 1905 > > > > > Einstein. > > > > > It is "unique" for the solar system, just as the pair of shoes that I > > > > wear are "unique" for me... > > > > I dont think so. You can change your shoes, but not the unique time > > > corresponding to the Solar System as long as it is maintained as a > > > closed one (I forgot to mention explicitly that basic condition when > > > talking about real inertial frames). > > > Sure we can - we can set t=0 whenever we want, and also choose our > > time standard. > > From your last answer I deduce that we dont share a common > interpretation about what is the time defined by 1905 Einstein. Let > us take two very well-known real inertial systems, the ECI and the > Solar System (SS). Let me ask you a very crucial question. Can be two > GPS clocks (for example one in a satellite and another in the Earths > surface) e-synchronized with respect to the ECI and at the same time > also e-synchronized with respect to the SS? > The essential difference between the (1905 Einstein) times of two > different inertial systems has no relation at all with the totally > arbitrary selection of initial instants and time standard units in > both systems. Perhaps you meant with "unique time", "unique synchronization"? Most people would call that not "absolute" but "relative" synchronization. Anyway, I'm not at all interested in debates over words. [..] Regards, Harald
From: harald on 20 Mar 2010 08:27 On Mar 19, 7:25 pm, GSS <gurcharn_san...(a)yahoo.com> wrote: > On Mar 19, 6:12 pm, "Inertial" <relativ...(a)rest.com> wrote:> "GSS" <gurcharn_san...(a)yahoo.com> wrote in message > > ..... > > >> Let us consider two identical precision atomic clocks, positioned at > >> points A and B, separated by a distance of about 30 km along east- > >> west direction, on the surface of earth. > > > As you are talking SR, you must be assuming that the surface of the earth is > > an inertial frame (so we'll ignore it rotating, or orbitting, and ignore > > gravity). > > No, I meant to ignore gravity effects only. > > > > >> Assume the two clocks A and B > >> are mutually synchronized through Einstein convention such that the > >> time taken, T_ab, by a laser pulse to propagate from A to B (as > >> measured from the clock readings of B and A) is the same as the time > >> taken, T_ba, by a laser pulse to propagate from B to A. > > > Which is, of course, obviously true. > > >> That means, > >> T_ab - T_ba = 0 which indicates e-synchronization of the two clocks. > > > Only if that is what the clocks show. The fact light takes the same time to > > travel the same distance at the same speed doesn't make the clocks > > synchronized. > > >> In your opinion, will this synchronization remain valid at least for a > >> 24 hour period? That is, if we take to and fro signal propagation time > >> readings at hourly intervals, will all readings show, > >> T_ab - T_ba = 0 > > > It will be valid forever, if they remain at rest in the inertial frame. > > Will it still be valid for ever, if they remain at rest only in the > local or lab frame fixed on the surface of earth? What do you think is > the effect of earth rotation on the mutual e-synchronization of two > clocks in the lab frame? > > > > >> Perhaps you may like to call this mutual synchronization of clocks A > >> and B as the 'local clock synchronization' valid in the local or lab > >> frame of the two clocks. > > > If you want to. > > >> Kindly explain the procedure for e-synchronization of the same two > >> atomic clocks A and B in the ECI or the GCRF frame. How exactly will > >> it be different from the local clock synchronization in practical > >> terms? > > > The clocks would have to be at rest in those frames. > > > If not, then you can of course have a whole series of appropriate clocks > > that ARE at rest in the frame you want (so A and B will be comoving past > > those clocks), and chose a time on those clocks (say 12:00), and whichever > > rest clocks A and B are adjacent to when those rest get to 12:00, copy that > > time to A and B. Then A and B will be in sync in that frame, and show the > > same time in that frame. But they won't be measured as ticking at the > > correct rate, so they will get more and more out of synch with other rest > > clocks they pass. > > I don't think you really mean what you write. > Do you seriously think there are some atomic clocks that are actually > at rest in the ECI or BCRF frames? Or can you ever make any atomic > clock ever at rest in the ECI or BCRF frames? > > >> Since the two clocks under consideration are simultaneously known to > >> be co-moving in the solar system at about 30 km/s, you may kindly > >> explain the procedure for e-synchronization of the same two atomic > >> clocks A and B in the solar system BCRF frame. > > > The clocks would have to be at rest in that frame. (Or see above) > > But how? > > >> How exactly will it be > >> different from the local clock synchronization in practical terms? > > > No different at all. But the same clocks are not going to be both at rest > > in more than one (non-eqivalent) inertial frame. > > >> Going one step still further,the two clocks under consideration are > >> simultaneously known to be co-moving in the Galactic reference frame > >> at about 200 km/s. Kindly explain the procedure for e-synchronization > >> of the same two atomic clocks A and B in the Galactic reference frame. > > > The clocks would have to be at rest in that frame. (Or see above) > > What I make out from your response is that two clocks A and B > considered above, can be e-synchronized in ECI or BCRf or Galactic > reference frames only if these clocks can be brought to rest in these > frames. Since it is practically impossible to bring the two clocks (at > rest on the surface of earth) to rest in ECI or BCRF or Galactic > reference frames, it implies that it is practically impossible to > mutually e-synchronize the two clocks in any of these inertial > reference frames. That means two atomic clocks A and B can be mutually > e-synchronized only in their local or lab frame and none else. All > talk of e-synchronizing two or more atomic clocks in different > inertial reference frames in relative uniform motion, is just > hypothetical day dreaming or gedanken. The synchronisation procedure in the ECI "frame" accounts for the speed of the clocks on the Earth's surface; that's also how GPS works (commonly called "Sagnac correction"). There is no reason to make any clocks "rest" in the ECI "frame". Regards, Harald
From: BURT on 20 Mar 2010 15:54 On Mar 20, 5:27 am, harald <h...(a)swissonline.ch> wrote: > On Mar 19, 7:25 pm, GSS <gurcharn_san...(a)yahoo.com> wrote: > > > > > > > On Mar 19, 6:12 pm, "Inertial" <relativ...(a)rest.com> wrote:> "GSS" <gurcharn_san...(a)yahoo.com> wrote in message > > > ..... > > > >> Let us consider two identical precision atomic clocks, positioned at > > >> points A and B, separated by a distance of about 30 km along east- > > >> west direction, on the surface of earth. > > > > As you are talking SR, you must be assuming that the surface of the earth is > > > an inertial frame (so we'll ignore it rotating, or orbitting, and ignore > > > gravity). > > > No, I meant to ignore gravity effects only. > > > >> Assume the two clocks A and B > > >> are mutually synchronized through Einstein convention such that the > > >> time taken, T_ab, by a laser pulse to propagate from A to B (as > > >> measured from the clock readings of B and A) is the same as the time > > >> taken, T_ba, by a laser pulse to propagate from B to A. > > > > Which is, of course, obviously true. > > > >> That means, > > >> T_ab - T_ba = 0 which indicates e-synchronization of the two clocks. > > > > Only if that is what the clocks show. The fact light takes the same time to > > > travel the same distance at the same speed doesn't make the clocks > > > synchronized. > > > >> In your opinion, will this synchronization remain valid at least for a > > >> 24 hour period? That is, if we take to and fro signal propagation time > > >> readings at hourly intervals, will all readings show, > > >> T_ab - T_ba = 0 > > > > It will be valid forever, if they remain at rest in the inertial frame. > > > Will it still be valid for ever, if they remain at rest only in the > > local or lab frame fixed on the surface of earth? What do you think is > > the effect of earth rotation on the mutual e-synchronization of two > > clocks in the lab frame? > > > >> Perhaps you may like to call this mutual synchronization of clocks A > > >> and B as the 'local clock synchronization' valid in the local or lab > > >> frame of the two clocks. > > > > If you want to. > > > >> Kindly explain the procedure for e-synchronization of the same two > > >> atomic clocks A and B in the ECI or the GCRF frame. How exactly will > > >> it be different from the local clock synchronization in practical > > >> terms? > > > > The clocks would have to be at rest in those frames. > > > > If not, then you can of course have a whole series of appropriate clocks > > > that ARE at rest in the frame you want (so A and B will be comoving past > > > those clocks), and chose a time on those clocks (say 12:00), and whichever > > > rest clocks A and B are adjacent to when those rest get to 12:00, copy that > > > time to A and B. Then A and B will be in sync in that frame, and show the > > > same time in that frame. But they won't be measured as ticking at the > > > correct rate, so they will get more and more out of synch with other rest > > > clocks they pass. > > > I don't think you really mean what you write. > > Do you seriously think there are some atomic clocks that are actually > > at rest in the ECI or BCRF frames? Or can you ever make any atomic > > clock ever at rest in the ECI or BCRF frames? > > > >> Since the two clocks under consideration are simultaneously known to > > >> be co-moving in the solar system at about 30 km/s, you may kindly > > >> explain the procedure for e-synchronization of the same two atomic > > >> clocks A and B in the solar system BCRF frame. > > > > The clocks would have to be at rest in that frame. (Or see above) > > > But how? > > > >> How exactly will it be > > >> different from the local clock synchronization in practical terms? > > > > No different at all. But the same clocks are not going to be both at rest > > > in more than one (non-eqivalent) inertial frame. > > > >> Going one step still further,the two clocks under consideration are > > >> simultaneously known to be co-moving in the Galactic reference frame > > >> at about 200 km/s. Kindly explain the procedure for e-synchronization > > >> of the same two atomic clocks A and B in the Galactic reference frame. > > > > The clocks would have to be at rest in that frame. (Or see above) > > > What I make out from your response is that two clocks A and B > > considered above, can be e-synchronized in ECI or BCRf or Galactic > > reference frames only if these clocks can be brought to rest in these > > frames. Since it is practically impossible to bring the two clocks (at > > rest on the surface of earth) to rest in ECI or BCRF or Galactic > > reference frames, it implies that it is practically impossible to > > mutually e-synchronize the two clocks in any of these inertial > > reference frames. That means two atomic clocks A and B can be mutually > > e-synchronized only in their local or lab frame and none else. All > > talk of e-synchronizing two or more atomic clocks in different > > inertial reference frames in relative uniform motion, is just > > hypothetical day dreaming or gedanken. > > The synchronisation procedure in the ECI "frame" accounts for the > speed of the clocks on the Earth's surface; that's also how GPS works > (commonly called "Sagnac correction"). There is no reason to make any > clocks "rest" in the ECI "frame". > > Regards, > Harald- Hide quoted text - > > - Show quoted text - Particles viibrate as they fall around their wave center. Mitch Raemsch
From: GSS on 20 Mar 2010 23:44
On Mar 20, 5:27 pm, harald <h...(a)swissonline.ch> wrote: > On Mar 19, 7:25 pm, GSS <gurcharn_san...(a)yahoo.com> wrote: > > > > > On Mar 19, 6:12 pm, "Inertial" <relativ...(a)rest.com> wrote:> "GSS" <gurcharn_san...(a)yahoo.com> wrote in message > > > ..... > > > >> Let us consider two identical precision atomic clocks, positioned at > > >> points A and B, separated by a distance of about 30 km along east- > > >> west direction, on the surface of earth. > > > > As you are talking SR, you must be assuming that the surface of the earth is > > > an inertial frame (so we'll ignore it rotating, or orbitting, and ignore > > > gravity). > > > No, I meant to ignore gravity effects only. > > > >> Assume the two clocks A and B > > >> are mutually synchronized through Einstein convention such that the > > >> time taken, T_ab, by a laser pulse to propagate from A to B (as > > >> measured from the clock readings of B and A) is the same as the time > > >> taken, T_ba, by a laser pulse to propagate from B to A. > > > > Which is, of course, obviously true. > > > >> That means, > > >> T_ab - T_ba = 0 which indicates e-synchronization of the two clocks. > > > > Only if that is what the clocks show. The fact light takes the same time to > > > travel the same distance at the same speed doesn't make the clocks > > > synchronized. > > > >> In your opinion, will this synchronization remain valid at least for a > > >> 24 hour period? That is, if we take to and fro signal propagation time > > >> readings at hourly intervals, will all readings show, > > >> T_ab - T_ba = 0 > > > > It will be valid forever, if they remain at rest in the inertial frame. > > > Will it still be valid for ever, if they remain at rest only in the > > local or lab frame fixed on the surface of earth? What do you think is > > the effect of earth rotation on the mutual e-synchronization of two > > clocks in the lab frame? > > > >> Perhaps you may like to call this mutual synchronization of clocks A > > >> and B as the 'local clock synchronization' valid in the local or lab > > >> frame of the two clocks. > > > > If you want to. > > > >> Kindly explain the procedure for e-synchronization of the same two > > >> atomic clocks A and B in the ECI or the GCRF frame. How exactly will > > >> it be different from the local clock synchronization in practical > > >> terms? > > > > The clocks would have to be at rest in those frames. > > > > If not, then you can of course have a whole series of appropriate clocks > > > that ARE at rest in the frame you want (so A and B will be comoving past > > > those clocks), and chose a time on those clocks (say 12:00), and whichever > > > rest clocks A and B are adjacent to when those rest get to 12:00, copy that > > > time to A and B. Then A and B will be in sync in that frame, and show the > > > same time in that frame. But they won't be measured as ticking at the > > > correct rate, so they will get more and more out of synch with other rest > > > clocks they pass. > > > I don't think you really mean what you write. > > Do you seriously think there are some atomic clocks that are actually > > at rest in the ECI or BCRF frames? Or can you ever make any atomic > > clock ever at rest in the ECI or BCRF frames? > > > >> Since the two clocks under consideration are simultaneously known to > > >> be co-moving in the solar system at about 30 km/s, you may kindly > > >> explain the procedure for e-synchronization of the same two atomic > > >> clocks A and B in the solar system BCRF frame. > > > > The clocks would have to be at rest in that frame. (Or see above) > > > But how? > > > >> How exactly will it be > > >> different from the local clock synchronization in practical terms? > > > > No different at all. But the same clocks are not going to be both at rest > > > in more than one (non-eqivalent) inertial frame. > > > >> Going one step still further,the two clocks under consideration are > > >> simultaneously known to be co-moving in the Galactic reference frame > > >> at about 200 km/s. Kindly explain the procedure for e-synchronization > > >> of the same two atomic clocks A and B in the Galactic reference frame. > > > > The clocks would have to be at rest in that frame. (Or see above) > > > What I make out from your response is that two clocks A and B > > considered above, can be e-synchronized in ECI or BCRf or Galactic > > reference frames only if these clocks can be brought to rest in these > > frames. Since it is practically impossible to bring the two clocks (at > > rest on the surface of earth) to rest in ECI or BCRF or Galactic > > reference frames, it implies that it is practically impossible to > > mutually e-synchronize the two clocks in any of these inertial > > reference frames. That means two atomic clocks A and B can be mutually > > e-synchronized only in their local or lab frame and none else. All > > talk of e-synchronizing two or more atomic clocks in different > > inertial reference frames in relative uniform motion, is just > > hypothetical day dreaming or gedanken. > > The synchronisation procedure in the ECI "frame" accounts for the > speed of the clocks on the Earth's surface; that's also how GPS works > (commonly called "Sagnac correction"). There is no reason to make any > clocks "rest" in the ECI "frame". > > Regards, > Harald In essence, Sagnac correction accounts for the effect of motion of the receiver during the transit time of the signal pulse from transmitter to the receiver. Here the main issue is that if you mutually synchronize two atomic clocks A and B (separated by distance D) on earth surface, can the *same* two clocks be mutually synchronized in the ECI and BCRF frames without first bringing them to *rest* in these frames? Inertial says you cannot. If you think these two clocks can be mutually synchronized in the ECI and/or BCRF frames without bringing them to *rest* in these frames, kindly explain that synchronization procedure. If you do succeed in synchronizing these two clocks in ECI and/or BCRF frames (while they are still at rest in their local or lab frame on the surface of earth) will their mutual synchronization in their lab frame be broken or maintained? GSS |