Notion of Absolute Clock Synchronization in SR
in [Relativity]
|
From: Sue... on 7 Apr 2010 14:49 On Apr 7, 2:36 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 7, 9:43 am, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > On Apr 7, 9:45 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 synchronization) is no longer valid in SR.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. > > > 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. > > > Can you show us a four-vector proof that the final term > > of that exercise, "elapsed proper time" > > preserves the relevant symmetries? http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications > > What "relevant symmetries" do you think a measurable physical quantity > should preserve? Time and energy might be a good for a start. What does the space-time curvature tell us about the muzzle velocity of a gun: A) In a gravitational potenetal. B) When signs are wrong converting from coordinate time. ;-) Sue... > Note your link talks about how *laws of physics* preserve certain > symmetries, but measurable physical quantities are not laws of > physics. I hope you don't get the two confused. > > > > > Sue... > > > > > 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 > >
From: PD on 7 Apr 2010 14:52 On Apr 7, 1:49 pm, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > On Apr 7, 2:36 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Apr 7, 9:43 am, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > On Apr 7, 9:45 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. > > > > 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. > > > > Can you show us a four-vector proof that the final term > > > of that exercise, "elapsed proper time" > > > preserves the relevant symmetries? > > http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications > > > > > What "relevant symmetries" do you think a measurable physical quantity > > should preserve? > > Time and energy might be a good for a start. Time and energy are not symmetries. What symmetries did you have in mind? And do you understand the difference between a measurable physical quantity and a physical law? [rest of nonsequiturs ignored] > > What does the space-time curvature tell > us about the muzzle velocity of a gun: > > A) In a gravitational potenetal. > > B) When signs are wrong converting from coordinate time. > > ;-) > > Sue... > > > Note your link talks about how *laws of physics* preserve certain > > symmetries, but measurable physical quantities are not laws of > > physics. I hope you don't get the two confused. > > > > Sue... > > > > > > 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 > >
From: Sue... on 7 Apr 2010 14:56 On Apr 7, 2:52 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 7, 1:49 pm, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > On Apr 7, 2:36 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Apr 7, 9:43 am, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > On Apr 7, 9:45 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. > > > > > 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. > > > > > Can you show us a four-vector proof that the final term > > > > of that exercise, "elapsed proper time" > > > > preserves the relevant symmetries? > > >http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications > > > > What "relevant symmetries" do you think a measurable physical quantity > > > should preserve? > > > Time and energy might be a good for a start. > > Time and energy are not symmetries. << Application of Noether's theorem allows physicists to gain powerful insights into any general theory in physics, by just analyzing the various transformations that would make the form of the laws involved invariant. For example: * the invariance of physical systems with respect to spatial translation (in other words, that the laws of physics do not vary with locations in space) gives the law of conservation of linear momentum; * invariance with respect to rotation gives the law of conservation of angular momentum; * invariance with respect to time translation gives the well-known law of conservation of energy >> http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications What symmetries did you have in > mind? > And do you understand the difference between a measurable physical > quantity and a physical law? > > [rest of nonsequiturs ignored] > > > > > What does the space-time curvature tell > > us about the muzzle velocity of a gun: > > > A) In a gravitational potenetal. > > > B) When signs are wrong converting from coordinate time. > > > ;-) > > > Sue... > > > > Note your link talks about how *laws of physics* preserve certain > > > symmetries, but measurable physical quantities are not laws of > > > physics. I hope you don't get the two confused. > > > > > Sue... > > > > > > > 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 > >
From: PD on 7 Apr 2010 15:35 On Apr 7, 1:56 pm, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > On Apr 7, 2:52 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Apr 7, 1:49 pm, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > On Apr 7, 2:36 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > On Apr 7, 9:43 am, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > > On Apr 7, 9:45 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. > > > > > > 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. > > > > > > Can you show us a four-vector proof that the final term > > > > > of that exercise, "elapsed proper time" > > > > > preserves the relevant symmetries? > > > >http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications > > > > > What "relevant symmetries" do you think a measurable physical quantity > > > > should preserve? > > > > Time and energy might be a good for a start. > > > Time and energy are not symmetries. > > << Application of Noether's theorem allows physicists to > gain powerful insights into any general theory in physics, > by just analyzing the various transformations that would > make the form of the laws involved invariant. For example: > > * the invariance of physical systems with respect > to spatial translation (in other words, that the laws > of physics do not vary with locations in space) gives > the law of conservation of linear momentum; > * invariance with respect to rotation gives the law > of conservation of angular momentum; > * invariance with respect to time translation gives > the well-known law of conservation of energy >> > > http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications > > What symmetries did you have in > > > mind? > > And do you understand the difference between a measurable physical > > quantity and a physical law? Right. Do you know the difference between a physical law (which is what your web blurb is referring to) and a measurable physical quantity (such as proper time)? So far, you show no ability to distinguish them at all. > > > [rest of nonsequiturs ignored] > > > > What does the space-time curvature tell > > > us about the muzzle velocity of a gun: > > > > A) In a gravitational potenetal. > > > > B) When signs are wrong converting from coordinate time. > > > > ;-) > > > > Sue... > > > > > Note your link talks about how *laws of physics* preserve certain > > > > symmetries, but measurable physical quantities are not laws of > > > > physics. I hope you don't get the two confused. > > > > > > Sue... > > > > > > > > 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 > >
From: Sue... on 7 Apr 2010 16:14
On Apr 7, 3:35 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Apr 7, 1:56 pm, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > On Apr 7, 2:52 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > On Apr 7, 1:49 pm, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > On Apr 7, 2:36 pm, PD <thedraperfam...(a)gmail.com> wrote: > > > > > > On Apr 7, 9:43 am, "Sue..." <suzysewns...(a)yahoo.com.au> wrote: > > > > > > > On Apr 7, 9:45 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. > > > > > > > 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. > > > > > > > Can you show us a four-vector proof that the final term > > > > > > of that exercise, "elapsed proper time" > > > > > > preserves the relevant symmetries? > > > > >http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications > > > > > > What "relevant symmetries" do you think a measurable physical quantity > > > > > should preserve? > > > > > Time and energy might be a good for a start. > > > > Time and energy are not symmetries. > > > << Application of Noether's theorem allows physicists to > > gain powerful insights into any general theory in physics, > > by just analyzing the various transformations that would > > make the form of the laws involved invariant. For example: > > > * the invariance of physical systems with respect > > to spatial translation (in other words, that the laws > > of physics do not vary with locations in space) gives > > the law of conservation of linear momentum; > > * invariance with respect to rotation gives the law > > of conservation of angular momentum; * invariance with respect to time translation gives the well-known law of conservation of energy >> http://en.wikipedia.org/wiki/Noether%27s_theorem#Applications > > > What symmetries did you have in > > > > mind? > > > And do you understand the difference between a measurable physical > > > quantity and a physical law? > > Right. Do you know the difference between a physical law (which is > what your web blurb is referring to) and a measurable physical > quantity (such as proper time)? > > So far, you show no ability to distinguish them at all. Remember... You have given up LET for SR so rulers are not dependent on inertial frames. Minkowski Space http://www.bartleby.com/173/17.html I can tape a metre stick to a gun barrel and that is a proper clock. K.E. = 1/2 mv^2 The hijackers of the world would be interested to hear from you which inertial frame most slows the clock and weakens the lawmam's bullet. Sue... > > > > > > [rest of nonsequiturs ignored] > > > > > What does the space-time curvature tell > > > > us about the muzzle velocity of a gun: > > > > > A) In a gravitational potenetal. > > > > > B) When signs are wrong converting from coordinate time. > > > > > ;-) > > > > > Sue... > > > > > > Note your link talks about how *laws of physics* preserve certain > > > > > symmetries, but measurable physical quantities are not laws of > > > > > physics. I hope you don't get the two confused. > > > > > > > Sue... > > > > > > > > > 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 > > |