Notion of Absolute Clock Synchronization in SR
in [Relativity]
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From: Inertial on 7 Apr 2010 20:31 "Da Do Ron Ron" <ron_aikas(a)hotmail.com> wrote in message news:e06c3616-730a-4d5e-84a1-bfa0328d9856(a)s9g2000yqa.googlegroups.com... > On Mar 12, 7:27 pm, "Inertial" <relativ...(a)rest.com> wrote: >> "Da Do Ron Ron" <ron_ai...(a)hotmail.com> wrote in >> messagenews:cf5a6f3a-22e3-4ca6-8e8c-592fc3c45cbf(a)15g2000yqi.googlegroups.com... >> >> >> >> > On Mar 11, 5:20 pm, "Inertial" <relativ...(a)rest.com> wrote: >> >> "Da Do Ron Ron" <ron_ai...(a)hotmail.com> wrote in >> >> messagenews:0df07b16-99d7-4f22-9342-c63357088dc0(a)upsg2000gro.googlegroups.com... >> >> >> > On Mar 11, 12:58 pm, PD <thedraperfam...(a)gmail.com> wrote: >> >> >> On Mar 11, 9:35 am, GSS <gurcharn_san...(a)yahoo.com> wrote: >> >> >> >> > Kindly illustrate the procedure, through some 'thought >> >> >> > experiment' >> >> >> > or 'gedanken', to achieve absolute clock synchronization for all >> >> >> > observers in different states of motion within our solar system. >> >> >> >> This cannot be done, given what we know about the laws of physics. >> >> >> > Careful, PD, ol' boy, you know that a negative can't be proved. >> >> >> Yes it can .. because we know that we can have three clocks where A >> >> and B >> >> are in sync (in one frame), and B and C are in sync (in another), but >> >> A >> >> and >> >> C are not (in either). That proves there is no such thing as absolute >> >> clock >> >> sync. >> >> > You did not prove that A and B were actually in synch, >> >> I don't have to *prove* that they are .. I am describing a scenario, and >> in >> that scenario we have synced the clocks .. that means they are in sync. >> > > By what process were they synch'd? When they show equal times as equal. A number of ways to do this. Send fixed speed signals between them, or sync them when at the same location and then move them apart. >> > so your >> > argument is no good. >> >> Yes it is >> >> > Besides, absolute synch can exist in a single frame between a >> > pair of clocks, and you cannot prove that this cannot happen. >> >> That is not ABSOLUTE sync. That is frame-dependent sync, because in >> OTHER >> frames those same clocks are NOT in sync >> >> Really .. this isn't that hard a concept to grasp > > Why are they not in synch per other frames? Because that is how reality works. We have to model reality .. not bend it to our wills.
From: BURT on 7 Apr 2010 21:26 The space frame allows energy all speeds up to below light. Energy flows always below light speed. Mitch Raemsch
From: Androcles on 7 Apr 2010 22:05 "Tom Adams" <tadamsmar(a)yahoo.com> wrote in message news:3cfbbdd8-1c7e-4113-9ea9-d9ee6a4cf187(a)g30g2000yqc.googlegroups.com... On Apr 7, 3:21 am, "Androcles" <Headmas...(a)Hogwarts.physics_x> wrote: > "Tom Adams" <tadams...(a)yahoo.com> wrote in message > > news:827aa470-d686-4b02-a943-ada1caebe193(a)g30g2000yqc.googlegroups.com... > On Mar 11, 11:35 am, GSS <gurcharn_san...(a)yahoo.com> wrote: > > > > > > > As per Newtonian notion of absolute space and time, clocks can be > > synchronized in absolute terms such that identical precision atomic > > clocks located anywhere within the solar system and in any state of > > motion, will read the same time t1 when a standard master clock reads > > t1. This notion of absolute clock synchronization implies the notion > > of absolute simultaneity. > > > However, as per SR, spatial distance and time measurements have been > > rendered 'relative' and cannot be the same value for different > > observers in different states of motion. As per SR the notion of > > global 'absolute simultaneity' is fundamentally invalid for different > > observers in different states of motion. Therefore, the notion of > > global 'absolute clock synchronization' (in contrast to e- > > synchronization) is no longer valid in SR. > > > Since the term 'absolute clock synchronization' is often used in > > discussions, I would like to request some Relativity experts to kindly > > clarify the precise definition of absolute clock synchronization in > > SR. Kindly illustrate the procedure, through some 'thought experiment' > > or 'gedanken', to achieve absolute clock synchronization for all > > observers in different states of motion within our solar system. > > > Further, I also need some expert opinion on the following situation, > > involving clock synchronization. > > > Two identical precision atomic clocks are positioned side by side at > > point A on the surface of earth and mutually synchronized to ensure > > that > > (a) their clock rates or frequencies are exactly matched or > > synchronized > > (b) their instantaneous timing offsets are eliminated to ensure that a > > common trigger pulse yields the same timing reading t1 from both > > clocks. > > > Assuming the inherent drift of the two atomic clocks is identical and > > well within 100 ps per day, it can be demonstrated that while the two > > clocks remain side by side, their synchronization, after a period of > > one day, is retained at well within one ns accuracy. > > > Let us shift one of the synchronized atomic clocks to a position B > > such that distance AB is about 30 km. > > Stop right there. You are outside of the scope of SR. All acceleration > is outside the scope. SR cannot address your question. > > Strictly speaking, the twin paradox is not part of SR since in > involves acceleration. The space-time paths that the twins take do > involve different elapsed times in a reference frame, but taking one > of the paths involves acceleration. > =========================================== > Stop right there. > Strictly speaking, the twin paradox is very much part of SR since it does > NOT involve acceleration. > The outbound journey is at velocity v and the inbound is at velocity -v, > the > path is a two-sided polygon. Yes, but the twin has to go from v to -v. ====================================== Not relevant, v is squared in tau = t * sqrt(1-v^2/c^2), so (-v)^2 = v^2. Cars go around oval race tracks without changing speed all the time, reversing their velocity. ====================================== > > "If we assume that the result proved for a polygonal line is also valid > for > a continuously curved line, we arrive at this result: If one of two > synchronous clocks at A is moved in a closed curve with constant velocity > until it returns to A, the journey lasting t seconds, then by the clock > which has remained at rest the travelled clock on its arrival at A will be > 1/2 t v^2/c^2 second slow." -- Einstein, 1905, "On the Electrodynamics of > Moving Bodies". Yeah, it's in the paper. But there is acceleration. ======================================= If there were then its duration and distance would be pertinent. Unless you can state their relevance then acceleration is just so much hand-waving, like Gordon Brown dog-paddling the economy as he sinks, flapping his paws up and down and saying "No", and "Should" without answering any questions. Einstein claims his result is proved for a polygonal line and a continuous curved line, there is no change in SPEED (not velocity) as the ship swings around the back of the star and returns to Earth. He contradicts his own xi = x'/sqrt(1-v^2/c^2), eta = y, zeta = z, but that's normal for his nonsense. ======================================= > Thence we conclude that clock B (having travelled and being younger than > clock A) meets clock A before clock A meets clock B. The clock are twin > clocks, and in real physics A meets B when B meets A. That's the paradox. No, there is no real paradox. ==================================================== Oh yes there is, http://www.merriam-webster.com/dictionary/paradox 2 a : a statement that is seemingly contradictory or opposed to common sense and yet is perhaps true b : a self-contradictory statement that at first seems true c : an argument that apparently derives self-contradictory conclusions by valid deduction from acceptable premises As the ship goes around turns 2 and 3 it travels at v = 0 when u = <unchanged speed>, so eta = y'/sqrt(1-u^2/c^2) and NOT eta = y Einstein wasn't bright enough to know the difference between speed and velocity, he was too busy reading sci-fi in school. ==================================================== One twin accelerated and the other did not. You can't just reverse A and B. =================================================== Einstein can! He can do as he likes, He's a god. He can defy the laws of physics. He's holy, a genius. =================================================== You can demonstrate the so-called "paradox" within SR by having the clock traveling at v pass close to another clock traveling back at - v. When they are close together they can synchronize. But when the clock traveling at -v gets back to the clock at rest, it will now be "younger" (less time ticked off) demonstrating that one path through space-time gets to the future faster than the other. ==================================================== That's what I said, B meets A before A meets B. It's a whole lot harder to do than mere instant acceleration in zero time. > > http://www.merriam-webster.com/dictionary/paradox > > 2 a : a statement that is seemingly contradictory or opposed to common > sense > and yet is perhaps true > > b : a self-contradictory statement that at first seems true > > c : an argument that apparently derives self-contradictory conclusions by > valid deduction from acceptable premises > > No need for any word salad about 'synchronized' or 'spacetime' or > 'acceleration', the paradox is: B meets A before A meets B, contradictory > to > the acceptable premise that A meets B when B meets A. > > ================================================ >
From: BURT on 7 Apr 2010 22:32 On Apr 7, 7:05 pm, "Androcles" <Headmas...(a)Hogwarts.physics_x> wrote: > "Tom Adams" <tadams...(a)yahoo.com> wrote in message > > news:3cfbbdd8-1c7e-4113-9ea9-d9ee6a4cf187(a)g30g2000yqc.googlegroups.com... > On Apr 7, 3:21 am, "Androcles" <Headmas...(a)Hogwarts.physics_x> wrote: > > > > > > > "Tom Adams" <tadams...(a)yahoo.com> wrote in message > > >news:827aa470-d686-4b02-a943-ada1caebe193(a)g30g2000yqc.googlegroups.com.... > > On Mar 11, 11:35 am, GSS <gurcharn_san...(a)yahoo.com> wrote: > > > > As per Newtonian notion of absolute space and time, clocks can be > > > synchronized in absolute terms such that identical precision atomic > > > clocks located anywhere within the solar system and in any state of > > > motion, will read the same time t1 when a standard master clock reads > > > t1. This notion of absolute clock synchronization implies the notion > > > of absolute simultaneity. > > > > However, as per SR, spatial distance and time measurements have been > > > rendered 'relative' and cannot be the same value for different > > > observers in different states of motion. As per SR the notion of > > > global 'absolute simultaneity' is fundamentally invalid for different > > > observers in different states of motion. Therefore, the notion of > > > global 'absolute clock synchronization' (in contrast to e- > > > synchronization) is no longer valid in SR. > > > > Since the term 'absolute clock synchronization' is often used in > > > discussions, I would like to request some Relativity experts to kindly > > > clarify the precise definition of absolute clock synchronization in > > > SR. Kindly illustrate the procedure, through some 'thought experiment' > > > or 'gedanken', to achieve absolute clock synchronization for all > > > observers in different states of motion within our solar system. > > > > Further, I also need some expert opinion on the following situation, > > > involving clock synchronization. > > > > Two identical precision atomic clocks are positioned side by side at > > > point A on the surface of earth and mutually synchronized to ensure > > > that > > > (a) their clock rates or frequencies are exactly matched or > > > synchronized > > > (b) their instantaneous timing offsets are eliminated to ensure that a > > > common trigger pulse yields the same timing reading t1 from both > > > clocks. > > > > Assuming the inherent drift of the two atomic clocks is identical and > > > well within 100 ps per day, it can be demonstrated that while the two > > > clocks remain side by side, their synchronization, after a period of > > > one day, is retained at well within one ns accuracy. > > > > Let us shift one of the synchronized atomic clocks to a position B > > > such that distance AB is about 30 km. > > > Stop right there. You are outside of the scope of SR. All acceleration > > is outside the scope. SR cannot address your question. > > > Strictly speaking, the twin paradox is not part of SR since in > > involves acceleration. The space-time paths that the twins take do > > involve different elapsed times in a reference frame, but taking one > > of the paths involves acceleration. > > =========================================== > > Stop right there. > > Strictly speaking, the twin paradox is very much part of SR since it does > > NOT involve acceleration. > > The outbound journey is at velocity v and the inbound is at velocity -v, > > the > > path is a two-sided polygon. > > Yes, but the twin has to go from v to -v. > ====================================== > Not relevant, v is squared in tau = t * sqrt(1-v^2/c^2), > so (-v)^2 = v^2. Cars go around oval race tracks without > changing speed all the time, reversing their velocity. > ====================================== > > > > > "If we assume that the result proved for a polygonal line is also valid > > for > > a continuously curved line, we arrive at this result: If one of two > > synchronous clocks at A is moved in a closed curve with constant velocity > > until it returns to A, the journey lasting t seconds, then by the clock > > which has remained at rest the travelled clock on its arrival at A will be > > 1/2 t v^2/c^2 second slow." -- Einstein, 1905, "On the Electrodynamics of > > Moving Bodies". > > Yeah, it's in the paper. But there is acceleration. > ======================================= > If there were then its duration and distance would be pertinent. > Unless you can state their relevance then acceleration is just so > much hand-waving, like Gordon Brown dog-paddling the economy > as he sinks, flapping his paws up and down and saying "No", > and "Should" without answering any questions. > > Einstein claims his result is proved for a polygonal line and a > continuous curved line, there is no change in SPEED (not velocity) > as the ship swings around the back of the star and returns to Earth. > He contradicts his own xi = x'/sqrt(1-v^2/c^2), eta = y, zeta = z, > but that's normal for his nonsense. > ======================================= > > > Thence we conclude that clock B (having travelled and being younger than > > clock A) meets clock A before clock A meets clock B. The clock are twin > > clocks, and in real physics A meets B when B meets A. That's the paradox. > > No, there is no real paradox. > ==================================================== > Oh yes there is, > http://www.merriam-webster.com/dictionary/paradox > > 2 a : a statement that is seemingly contradictory or opposed to common sense > and yet is perhaps true > b : a self-contradictory statement that at first seems true > c : an argument that apparently derives self-contradictory conclusions by > valid deduction from acceptable premises > > As the ship goes around turns 2 and 3 it travels at v = 0 when u = > <unchanged speed>, > so > eta = y'/sqrt(1-u^2/c^2) > and NOT > eta = y > Einstein wasn't bright enough to know the difference between speed > and velocity, he was too busy reading sci-fi in school. > ==================================================== > > One twin accelerated and the other did not. You can't just reverse A > and B. > =================================================== > > Einstein can! He can do as he likes, He's a god. He can defy the laws of > physics. He's holy, a genius. > =================================================== > You can demonstrate the so-called "paradox" within SR by having the > clock traveling at v pass close to another clock traveling back at - > v. When they are close together they can synchronize. But when the > clock traveling at -v gets back to the clock at rest, it will now be > "younger" (less time ticked off) demonstrating that one path through > space-time gets to the future faster than the other. > ==================================================== > That's what I said, B meets A before A meets B. It's a whole lot > harder to do than mere instant acceleration in zero time. > > > > > > >http://www.merriam-webster.com/dictionary/paradox > > > 2 a : a statement that is seemingly contradictory or opposed to common > > sense > > and yet is perhaps true > > > b : a self-contradictory statement that at first seems true > > > c : an argument that apparently derives self-contradictory conclusions by > > valid deduction from acceptable premises > > > No need for any word salad about 'synchronized' or 'spacetime' or > > 'acceleration', the paradox is: B meets A before A meets B, contradictory > > to > > the acceptable premise that A meets B when B meets A. > > > ================================================- Hide quoted text - > > - Show quoted text -- Hide quoted text - > > - Show quoted text - 4 dimensional space and aether is curved round. Mitch Raemsch
From: BURT on 8 Apr 2010 01:22
On Apr 7, 6:45 am, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 7, 1:32 am, Tom Adams <tadams...(a)yahoo.com> wrote: > > > > > > > On Mar 11, 11:35 am, GSS <gurcharn_san...(a)yahoo.com> wrote: > > > > As per Newtonian notion of absolute space and time, clocks can be > > > synchronized in absolute terms such that identical precision atomic > > > clocks located anywhere within the solar system and in any state of > > > motion, will read the same time t1 when a standard master clock reads > > > t1. This notion of absolute clock synchronization implies the notion > > > of absolute simultaneity. > > > > However, as per SR, spatial distance and time measurements have been > > > rendered 'relative' and cannot be the same value for different > > > observers in different states of motion. As per SR the notion of > > > global 'absolute simultaneity' is fundamentally invalid for different > > > observers in different states of motion. Therefore, the notion of > > > global 'absolute clock synchronization' (in contrast to e- > > > synchronization) is no longer valid in SR. > > > > Since the term 'absolute clock synchronization' is often used in > > > discussions, I would like to request some Relativity experts to kindly > > > clarify the precise definition of absolute clock synchronization in > > > SR. Kindly illustrate the procedure, through some 'thought experiment' > > > or 'gedanken', to achieve absolute clock synchronization for all > > > observers in different states of motion within our solar system. > > > > Further, I also need some expert opinion on the following situation, > > > involving clock synchronization. > > > > Two identical precision atomic clocks are positioned side by side at > > > point A on the surface of earth and mutually synchronized to ensure > > > that > > > (a) their clock rates or frequencies are exactly matched or > > > synchronized > > > (b) their instantaneous timing offsets are eliminated to ensure that a > > > common trigger pulse yields the same timing reading t1 from both > > > clocks. > > > > Assuming the inherent drift of the two atomic clocks is identical and > > > well within 100 ps per day, it can be demonstrated that while the two > > > clocks remain side by side, their synchronization, after a period of > > > one day, is retained at well within one ns accuracy. > > > > Let us shift one of the synchronized atomic clocks to a position B > > > such that distance AB is about 30 km. > > > Stop right there. You are outside of the scope of SR. All acceleration > > is outside the scope. SR cannot address your question. > > This is a mistake on two fronts. SR can and does routinely handle > accelerations. Accelerations that create motion are always dectable by weight of energy fluctuation. Motion in this way is detectable by weight when it begins and when it ends. Mitch Raemsch > Secondly, the resolution of the twin paradox is a straightforward > implication of the fact that straight world lines have longer proper > time integrated along the path, compared to bent world lines. This is > something that can be seen in a spacetime diagram from basic SR. > Penrose makes this point very succinctly, for example. > If a train can watch the station's clock when passing and the station's clock is running slow when does that end? And how can it age the most if it is always seen by the train to run slower? Mitch Raemsch > > > > > Strictly speaking, the twin paradox is not part of SR since in > > involves acceleration. The space-time paths that the twins take do > > involve different elapsed times in a reference frame, but taking one > > of the paths involves acceleration. > > > > As per Newtonian notion of > > > absolute space and time, the mutual synchronization of the two clocks, > > > positioned at points A and B, will be retained in tact and this > > > synchronization can be referred as 'absolute synchronization'. But > > > according to SR, the mutual synchronization of the two clocks will > > > 'breakdown' during the shifting of one of the clocks from point A to > > > point B. Since 'after' shifting of one clock to point B on the surface > > > of earth, there is no relative motion between the two clocks, their > > > time rates or frequencies will again 'become' synchronized. Therefore, > > > the only persisting effect of the 'synchronization breakdown' during > > > shifting or repositioning of the two clocks, will be a motion induced > > > constant time offset, say dT, in the instantaneous readings of the two > > > clocks. > > > > My question to the learned Relativity experts is: > > > What is the order of magnitude of this 'relative motion induced' > > > timing offset dT between the two clocks? > > > Can it be precisely calculated in SR? Is it likely to be within a few > > > nanoseconds or less? > > > > Suppose we now shift the clock at point B to bring it back to point A, > > > (with an identical speed and acceleration profile), will this timing > > > offset dT now increase to 2.dT or reduce to zero? > > > > I shall be thankful to the Relativity experts for their valuable > > > opinions and clarifications. > > > > GSS- Hide quoted text - > > - Show quoted text -- Hide quoted text - > > - Show quoted text - Acceleration is speed passing through every quantity inbetween until it arives at an end speed; all down to the infinitely small. Mitch Raemsch |