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The SR Question of the Century

by Martin Miller
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russ_watters
#217
Jun1-04, 02:06 PM
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P: 22,300
Quote Quote by Martin Miller
Did you know that no one has ever used two clocks in one
frame to measure light's speed? Have you ever wondered
why this is so?
It would surprise me if it hasn't been done, but if it hasn't, there's a simple reason: its redundant since both clocks say exactly the same thing.
wisp
#218
Jun2-04, 07:30 AM
P: 179
Quote Quote by russ_watters
It would surprise me if it hasn't been done, but if it hasn't, there's a simple reason: its redundant since both clocks say exactly the same thing.
Not so, if this test is done by a professional body it will kill off Einstein's SR in one go.
I can't think of anything more embarrassing than to find the fundamental pillar upon which modern physics bases many of its theories, has a dirty great crack in it.
The sooner this experiment is done the better. It is the most important challenge that SR has to face. I hope SR passes, but I think it will prove to be its undoing.
ahrkron
#219
Jun2-04, 12:50 PM
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P: 734
Physics experiments are currently taking care of much more delicate business. SR has been tested continuously and detailedly since 1905. Despite the wish of many that would like to "uncover the truth about SR", the theory is extremely well established due to its excellent agreement with experiment.

Currently, experimental physics is geared towards much different problems. SR is not an issue anymore. Current efforts have to do with many other aspects of the models we have for nature (CP violation, quark-hadron duality, high temp superconductors, dark matter, supersymmetry, etc.). The type of discrepancies between theory and experiment are clearly not coming from something as basic as SR. If that was the case, the discrepancies would be all over the place, QFT (which is based on SR) would not work, the Standard Model of particle physics wouldn't be able to predict with an 11-digit accuracy, and nobody would be able to hide it.
russ_watters
#220
Jun2-04, 01:30 PM
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P: 22,300
Quote Quote by wisp
Not so, if this test is done by a professional body it will kill off Einstein's SR in one go.
I can't think of anything more embarrassing than to find the fundamental pillar upon which modern physics bases many of its theories, has a dirty great crack in it.
The sooner this experiment is done the better. It is the most important challenge that SR has to face. I hope SR passes, but I think it will prove to be its undoing.
Why would two identical clocks sitting next to each other in the same frame show different times and what would that say about SR (besides 'we need better clocks to test SR...')?
Martin Miller
#221
Jun2-04, 01:49 PM
P: 49
[Martin Miller wrote:]
Did you know that no one has ever used two clocks in one
frame to measure light's speed? Have you ever wondered
why this is so?

[russ_watters wrote:]
It would surprise me if it hasn't been done, but if it hasn't,
there's a simple reason: its redundant since both clocks say
exactly the same thing.

[MM replies:]
It has not been done, but not because of your reason; the real
reason is the fact that no physicist knows how to correctly
synchronize clocks.

-------------

[ahrkron declared:]
Physics experiments are currently taking care of much more delicate
business. SR has been tested continuously and detailedly since 1905.

[MM replies:]
Shall this urban legend never die?
Which part of SR has been tested?
Who has tested the basis of SR, namely, the light postulate?

No part of SR is testable because all parts of it are based
100% on a definition.

Every result of SR is a result of Einstein's definition of
synchronization, a mere convention given by man, and having
zilch to do with nature or physics.

For example, SR's "time dilation" or "clock slowing" is
merely an effect of Einstein's definition which relates
clocks incorrectly which in turn causes observers to see
a passing clock "run slow."

Here is how this happens, for those who need pictures:

passing clock
[3]-->
[3]------Frame A------[4]


------------------------[4]-->
[4]------Frame A------[5]

Although all three clocks really run at the same rate,
observers using Einstein's asynchronous clocks "see the
passing clock run slow."

SR per se has nothing to do with actual or real or physical
or intrinsic clock slowing because it does not even know how
to measure it. Also, Einsteinian observers in different frames
find different "rhythms" for the _same_ clock, whereas it is
physically impossible for one clock moving inertially to have
more than one intrinsic rhythm, so we know that SR does not
address or pertain to intrinsic clock rhythms.

And it is impossible to overstate the importance of getting
two clocks correctly related because all two-clock measurements
depend upon this, including light's one-way speed.
russ_watters
#222
Jun2-04, 02:26 PM
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P: 22,300
Quote Quote by Martin Miller
It has not been done, but not because of your reason; the real
reason is the fact that no physicist knows how to correctly
synchronize clocks.
Sorry I asked and I should have guessed - your objections are (of course) based on misunderstandings of the theory and definitions of the terms involved. That your thought experiment is wrong is easily demonstrated by flipping on a GPS receiver.

Synchronizing clocks is trivially easy and is done all the time (quite literally).
Martin Miller
#223
Jun3-04, 12:20 PM
P: 49
[russ_watters claimed:]
Synchronizing clocks is trivially easy and is done all the
time (quite literally).

[MM replies:]
So how do the GPS scientists obtain absolute simultaneity
(or absolute synchronization) in violation of Einstein's
relative simultaneity?

(You do not seem to be aware of the fact that the GPS
works not because of synchronous clocks but because of
geometric corrections which can even override the US
military's deliberate data degradation.)
russ_watters
#224
Jun3-04, 01:01 PM
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P: 22,300
Quote Quote by Martin Miller
[russ_watters claimed:]
Synchronizing clocks is trivially easy and is done all the
time (quite literally).

[MM replies:]
So how do the GPS scientists obtain absolute simultaneity
(or absolute synchronization) in violation of Einstein's
relative simultaneity?

(You do not seem to be aware of the fact that the GPS
works not because of synchronous clocks but because of
geometric corrections which can even override the US
military's deliberate data degradation.)
Absolute simultaneity? Who said anything about that? All I said was they synchronize the clocks.

Geometric corrections? You are aware that GPS satellites contain clocks, right? You are aware that the signals sent from the satellites to the recievers are time-coded signals, right? You are aware that the satellite clocks are monitored and corrected by clocks in ground stations, right?

I know you think you're being clever/coy by changing/ignoring definitions and throwing in irrelevant words as if they were important, but it really doesn't help you here: to argue against scientists about a scientific theory, you (whether you like it or not) have to follow their rules. Not following them just makes your arguments look silly.
ahrkron
#225
Jun3-04, 03:54 PM
Emeritus
PF Gold
P: 734
Quote Quote by Martin Miller
Shall this urban legend never die?
Which part of SR has been tested?
Urban legend? now that is funny.

Pretty much all of SR has been thoroughly tested. this page has a good compilation of references to serious physics articles about experimental tests of SR.

The following is a quote from that page:
Physics, as a natural science, is based on empirical facts. Physical theories cannot be based just on speculation or suspicion. On the other hand it is always reasonable to have doubts concerning established theories. Reading the posts in sci.physics.relativity I have got the impression, that the huge experimental support for this theory is sometimes not well known. The list of experiments below shows that the SRT is really tested very well. Hypotheses which claim, that SRT is just "wrong" have to show that all the experiments mentioned below had errors or that their interpretation is not correct.

There is a lot of redundancy in these experimental tests. There are also a lot of indirect tests of SRT which are not included in the list shown below. This list of experiments is NOT complete! I cannot guarantee, that the literature list has no mistakes. If I get a positive feedback, I am willing to update the list shown below and to correct all possible errors.

For those seriously concerned about this subject there is an essential new reference book: "Special Relativity and its Experimental Foundation" by Yuan Zhong Zhang, World Scientific (1996).
(the color emphasis is mine)

Quote Quote by Martin Miller
Who has tested the basis of SR, namely, the light postulate?
Look at section VII in that page.

No part of SR is testable because all parts of it are based 100% on a definition.

Every result of SR is a result of Einstein's definition of
synchronization, a mere convention given by man, and having zilch to do with nature or physics.
"100% definition". Can you point out the what definition you are talking about, and how it affects the measurement of speeds, masses, energies and electromagnetic fields? Please take into account that, when doing an experiment to test SR, the readings are not obtained from SR, but from the actual detectors (which, of course, are not "programmed with SR equations").
wisp
#226
Jun4-04, 07:41 AM
P: 179
Pretty much all of SR has been thoroughly tested. this page has a good compilation of references to serious physics articles about experimental tests of SR.
None of these tests compensate for the lack of one-way light speed measurements. The one-way tests that have been done are not accurate enough to prove or disprove SR.
And it is not necessary for all these tests to fail to prove SR false. It only takes one test to fail a theory. Much of the relativistic effects used by SR can be supported by absolute ether theories.
If a one-way test using two clocks shows that the speed of light is not constant because of the motion of the clocks' frame relative to the ether, then relativity is false.
Martin Miller
#227
Jun4-04, 02:17 PM
P: 49
[russ_watters asked:]
Absolute simultaneity? Who said anything about that?
All I said was they synchronize the clocks.

[MM replies:]
You did, "dummy." Absolute synchronization is
synonymous with absolute simultaneity, and one
would assume that your "synchronize the clocks"
means "absolutely synchronize the clocks," or
else, why bother.

This conversation has obviously reached its
limits; you merely assert unsubstantiated stuff
over and over, whilst completely ignoring any
and all challenges such as "How can two clocks
be correctly related?" and "How do the GPS folk
actually absolutely synchronize clocks?"

BTW, I think that if you really dig into the GPS
system, you will soon find that even their clocks
are related per Einstein's definition of clock
synchronization, a definition that merely dictates
one-way light speed invariance/isotropy. (This has
to be true because there is no other definition of
synchronization available, sir.)
Martin Miller
#228
Jun4-04, 02:45 PM
P: 49
[ahrkron wrote:]

Originally Posted by Martin Miller
Who has tested the basis of SR, namely,
the light postulate?

Look at section VII in that page.

[MM replies:]
It is you who needs to look at Section VII because
that section says zilch about light's one-way speed
between two clocks. (All it talks about is the fact
of light's source-independent nature.)

If you are silly enough to still insist that Sect VII
pertains to light's one-way speed per two clocks, then
please let us know how the clocks were synchronized.

Quote:
No part of SR is testable because all parts of it are based
100% on a definition.
Every result of SR is a result of Einstein's definition of
synchronization, a mere convention given by man, and having
zilch to do with nature or physics.

"100% definition". Can you point out the what definition you
are talking about, and how it affects the measurement of speeds,
masses, energies and electromagnetic fields? Please take into
account that, when doing an experiment to test SR, the readings
are not obtained from SR, but from the actual detectors (which,
of course, are not "programmed with SR equations").

[MM replies:]
'Round and 'round we go, where we'll stop, no one knows.

And here you are trying to discuss SR sans a knowledge of
its basis, Einstein's definition of clock synchronization.

And you are wrong about the "detectors" not being programmed
with SR equations -- the only detectors used in SR are clocks,
and every clock has been related to every other clock (in any
given frame) by Einstein's definition, a convention given only
by man, and which dictates one-way invariance/isotropy.

That is how the programming affects the speed of electromagnetic
fields which are moving through space (i.e., light waves).

And here is how this programming affects all other two-clock
**speed** measurements in SR:

[1] Since Einstein's clocks are asynchronous, all two-clock
measurements in SR are incorrect.
[2] Since Einstein's clock are forced by mere definition from
man to obtain c in all frames for light no matter how a frame
may move through space, the two-clock speeds of any other rapidly-
moving entities are distorted downward.

And here is how this programming affects all two-clock
**mass** measurements in SR:

Since the only tools (or instruments) in SR are clocks and
rods, all mass measurements must involve clocks and rods, and
therefore all mass measurements are incorrect due to the
asynchronousness of Einstein's clocks. For example, despite
the simple and obvious fact that a given object moving at
a single velocity cannot have more than one physical mass,
SR observers in different frames find _different_ masses for
one and the same passing object. This proves that SR does not
pertain to intrinsic or actual masses.

And here is how this programming causes **time dilation**
in SR:

passing clock
[3]-->
[3]------Frame A------[4]


------------------------[4]-->
[4]------Frame A------[5]

Although all three clocks really run at the same rate,
observers using Einstein's asynchronous clocks "see the
passing clock run slow."

SR per se has nothing to do with actual or real or physical
or intrinsic clock slowing because it does not even know how
to measure it. Also, Einsteinian observers in different frames
find different "rhythms" for the _same_ clock, whereas it is
physically impossible for one clock moving inertially to have
more than one intrinsic rhythm, so we know that SR does not
address or pertain to intrinsic clock rhythms.

Any more questions from the unknowledgeable?
ahrkron
#229
Jun5-04, 12:20 PM
Emeritus
PF Gold
P: 734
Let me recap:

Martin Miller asked:
Who has tested the basis of SR, namely, the light postulate?
To which I said:
Quote Quote by ahrkron
Look at section VII in that page.
Then, his answer is
Quote Quote by Martin Miller
It is you who needs to look at Section VII because that section says zilch about light's one-way speed between two clocks. (All it talks about is the fact of light's source-independent nature.)
i.e, you accept (in blue) that the site talks about light's source-independent nature. Your not having posted anything on that respect seems to imply that you either have no problem with that part, that you cannot deny the experimental support showed in the articles refered to in that page, or that you concede the point.

Now, you need to make clear for us what is the connection between the light postulate (which is well supported experimentally, as you seemingly accepted), and your idea of "light's one-way speed between two clocks".

You need to do so in a way that does not contradict the experiments reported in that page. And, of course, that does not mean just the little mention on the webpage, but the actual peer-reviewed articles.

I'm not able to do much this weekend, but I'll try to look for the articles later on the week. If I find them, I'll try to post at least the abstracts, so we can make this a real discussion.
Martin Miller
#230
Jun7-04, 01:01 PM
P: 49
[ahrkron wrote:]
Now, you need to make clear for us what is the connection between
the light postulate (which is well supported experimentally, as you
seemingly accepted), and your idea of "light's one-way speed between
two clocks".

You need to do so in a way that does not contradict the experiments
reported in that page. And, of course, that does not mean just the
little mention on the webpage, but the actual peer-reviewed articles.

[MM replies:]
The problem here is the fact that you are confused re Einstein's
light postulate.

The following site contains the following definition:
http://www.physics.cornell.edu/cours...2/16/concepts/

The Speed of Light Postulate
"The speed of light in vacuum, measured in any inertial reference frame,
always has the same value of c, no matter how fast the source of light
and the observer are moving relative to each other."

Did you notice the key word "measured"?

It means "measured by using two clocks."
(We don't need a postulate for light's round-trip, one-clock speed
because it has long been c per direct experiment, but, as I have
said, there has been no corresponding one-way experiment.)

In other words, Einstein's light postulate does not pertain to the
source-independency of light, but to the measured one-way speed of
light per two clocks in any given frame.

Do you see the light now?
Nereid
#231
Jun19-04, 04:22 PM
Emeritus
Sci Advisor
PF Gold
P: 4,014
Quote Quote by geistkiesel
1) Yes, If an Einstein gedunken experiment described in "Relativity" page 25 - 27 counts as an experiment then I can answer unambiguously Yes to 1). SR through the derived consequences of simultaneity loss predicts such loss for a moving platform that passes the midpoint of two photons emitted simultaneously from A and B with the movng platform located at the midpoint M of A nad B. The moving platform by detecting the light from the B source then the A source is hereby shown to necessitate the discarding of the concept of "simultaneity". The different arrival times lead the observer to conclude the photons were not emitted simultaneously.

2) No the prediciton was not correct.This is not the only possibility the moving observer can intitally make. She could observe that if she were moving the difference in the photons arrival on the moviong platform could result from the motion of the platform. Working backwards we can show the fallacy of this conclusion by clicking here.

Basically, the moving platform observer zeros her clock when passing the midpoint and measures t1', the instant the B photon arriives, and t2' the instant the A photon arrives. By making the assumption, to be tested, that she passed the midpoint of two emitted photons at M (where her clocks were zeroed) she ultimatey arrives at an expression t1' = (c-1)/2 = k. Comparing k with the measurd t1' proves simultaneity if t1' = k and one or the other photons was emitted first depending on the difference in t1' and k.

3)It is a gedunken experiment discussed in the literature with some repititon and depth.

4) No, see the link above.
Perhaps I should have been more clear; 'experiments' refers to real experiments, not 'gedunken's.

Thought experiments play a useful role in the development of a new idea; they can bring potential inconsistencies into sharp focus (so the folk developing the theories can make refinements, or scrap the theory), and they can suggest experiments which, if carried out, should yield a clear result - either consistency with the theory, or inconsistency.

However, by and in themselves, thought experiments don't tell you anything about the real world; only stuff done in a lab - with equipment - or the field - with detectors etc - can test an idea or theory.

So, can you provide details of an experiment - done in a lab, in the field, or with telescopes (etc) - whose results are inconsistent with SR?

Perhaps an example by contrast would help: "Are there any experiments - done in a lag, in the field, or with telescopes (etc) - whose results are inconsistent with the Newtonian theory of gravity?" The answer is, of course, yes! Dozens and dozens of them, from the advance of the perihelion of Mercury, to the bending of EM by the Sun's mass (and the Shapiro effect) as observed recently with the Cassini spaceprobe, to observations of binary pulsars.
loseyourname
#232
Jun19-04, 04:40 PM
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Quote Quote by Martin Miller
It means "measured by using two clocks."
(We don't need a postulate for light's round-trip, one-clock speed
because it has long been c per direct experiment, but, as I have
said, there has been no corresponding one-way experiment.)

In other words, Einstein's light postulate does not pertain to the
source-independency of light, but to the measured one-way speed of
light per two clocks in any given frame.

Do you see the light now?
What you are proposing isn't possible. Even in principle, there is no way to measure the one-way speed of light using only one clock. The constancy of the speed of light is the reason we get the Lorentz coordinate transformations rather than Galilean transformations, which assume absolute time and a variable speed of light. Therefore, any experiment that confirms the Lorentz transformations confirms the absolute nature of the speed of light and hence confirms SR. I'm aware that there exist other explanations given, but SR is the parsimonious theory.
reilly
#233
Jun19-04, 07:11 PM
Sci Advisor
P: 1,082
[QUOTE=Martin Miller]Nereid noted:
"Einstein's theories ... have been tested in the
crucible of experiment and observation, and have
passed with flying colours."

Sorry to burst your bubble, "Mr. Nereid," but as
far as Einstein's special relativity goes, your
above is purely an urban legend.

There have been exactly zero tests of SR.
***************
You must be joking.

We must live in alternate universes. SR is tested, for example in every high energy particle experiment-relativistic kinematics, using momentum and enrgy rather than space and time- has yet to be found wanting, and it is as basic as it gets in much of today's physics. The Dirac equation, QED, the Standard Theory all SR based, do pretty well, and all are key to today's physics. Why even radar can help test SR. SR is used in the design of accelerators. The arguments are ultimately "preponderance of evidence arguments", and for SR this means many thousands of experiments.

Also be aware that the various arguments/discussions of clocks, measuring rods, time dilation and so forth are simply designed to help make the math more understandable. The verbal arguments can, if not handled with care, lead to problems. The math of SR is as close to perfect as theory can be. You want to discredit SR, go for the hard stuff, like particle physics. Like, show that the Thomas Precession is fake, or something like that.

If this is all an urban myth, then most physicists live in a huge city.

Reilly Atkinson
geistkiesel
#234
Jun21-04, 01:20 AM
P: 565
Quote Quote by Nereid
Perhaps I should have been more clear; 'experiments' refers to real experiments, not 'gedunken's.

Thought experiments play a useful role in the development of a new idea; they can bring potential inconsistencies into sharp focus (so the folk developing the theories can make refinements, or scrap the theory), and they can suggest experiments which, if carried out, should yield a clear result - either consistency with the theory, or inconsistency.

However, by and in themselves, thought experiments don't tell you anything about the real world; only stuff done in a lab - with equipment - or the field - with detectors etc - can test an idea or theory.

So, can you provide details of an experiment - done in a lab, in the field, or with telescopes (etc) - whose results are inconsistent with SR?

Perhaps an example by contrast would help: "Are there any experiments - done in a lag, in the field, or with telescopes (etc) - whose results are inconsistent with the Newtonian theory of gravity?" The answer is, of course, yes! Dozens and dozens of them, from the advance of the perihelion of Mercury, to the bending of EM by the Sun's mass (and the Shapiro effect) as observed recently with the Cassini spaceprobe, to observations of binary pulsars.
If there is a consistently generated flaw in SR then SR will be SR whatever and however tested. I will suggest you look at Groubnded's thread for some up to date informtion. Also, if Eibnsteing proposes a Gebndunken, you cannot complain because others discuss that gedunken can you?

Try this one for size: Virtually all experiments discussed where there is a stationary platform and a moving platform make a huge error ion logic. Stationary means stationary, ie. v = 0. Therefiore, when making a conmparison with a moving frame and there is the ineviable claim that each frame is equivalent such that the moving and styationary frames can be exchanged, is physically inpossible to do. Again, "stationary frame" means v = 0, or said in other words, the stationary frame is assumed as an absolute v = 0, from which all measurements are ultimately measured.
-----------------------------------------------------------------------
All moving frame values are non-primed with the exception of M, the consistent location of the observer O in the moving frame.

At no time is there an inference that M was at the midpoint of the A and B photons emitted in the stationary frame.

To demonstrate the following:

Einsteins moving train calculation indicating when the oncoming B photon is detected at t1 the A photon was located at a position consistent with t1. Said in other words, as t1 is determined from t0 which locates M at t0, the A and B were equidistant to M(t0) when t = t1.

Proof:
A moving observer located at M on a moving frame passes through the midpoint M of photon sources located at A and B in the stationary frame just as A and B emit photons. M is moving along a line connecting A and B, toward B.

At this instant the moving source t = t0. Later the moving observer detects the photon from B at t1, and later the photon from A at t2. The observer has measured her velocity wrt the stationary frame as v. Determine the position of the A photon at tx in terms of t0, t1, t2, and v when the B photon was detected at t1.

The photon from A must reach the position of M when t = t2. Therefore, the distance traveled by the A photon during Δt = t2 t1, is Δtc. This is equal to the distance cΔt = vΔt + vt1 + vtx . Now we rearrange somewhat to arrive at, vtx = vΔt cΔt + vt1. Now as vΔt - cΔt is just -vtx - vt1

vtx = -vtx - vt1 vt1

2tx = -2t1

tx = -t1

Therefore, in the moving frame the photon from A and the photon from B were equidistant from M(t0) at t1.


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