Einstein postulated that light's one-way speed 
between two clocks c, but this measurement has 
never been made.* I would like to know why. It 
can't be due to a lack of technology because it 
has never been done even on paper (using ideal 
clocks). This tells me that it cannot be done, 
not even on paper, but it is important to know 
if this is answer is correct because special 
relativity is based on Einstein's light postulate, 
which, as I said, claims invariance and isotropy 
for light's one-way speed between two clocks.

*(Properly, that is, which means between two 
clocks which are at rest relative to each other; 
if one of the clocks moves, then we have clock 
slowing, and the measurement is invalidated.)

[ http://www.journaloftheoretics.com/Articles/1-1/jones-f1.html ]
might be a useful read....although, I'll be honest: this sh*t's
confusing!

I think the reason no one has documented an experiment as you describe
is that the results are predictable-- practically everyone believes
that if you shoot a light beam from clock 1 at time t1, that it will
arrive at clock 2 at t2, which is just t2-t1=d/c where d is the
distance between the clocks and c is the known speed of light (and
this website describes how we have measured the exact speed of light,
follow the links: http://www.what-is-the-speed-of-light.com/foucault-speed-of-light.html
--these experiments are really not that different than the experiment
that you are looking for, if I understand your question correctly).
I'm sure this has been done, but it would be hard to find published
results of such an experiment, since it is pretty much a fact. I know
there have been documented experiments of atomic clocks which, as you
say, were in movement relative to each other. But I'm not sure I see
the point of the experiment that you describe. I don't know how you
are applying it to einstein's theory. You seem to imply that it is
essential to the theories of einstein, but the speed of light could be
5 mph and the theories would still hold true. They are based on
mathematics where c is the speed of light, but nowhere in his theories
is the actual value of c required.

If pukinje has the right slant, billions of peices of data are
available as messages are sent by Geo-sychronous satellite, a distance
of about 72,000 kilometers,round trip. The travel time of the signal
is about 1/4 second which can likely be measured to an accuracy of
about one part per billion.   Neil

This asker is not interested in

" I would like to know why .. this was not done"

He has a  theory which is alternative to Einstein's 
and is convinced that his/her is the correct one.
Proceed ar your own risk.

Hedgie

Since "hedgie" has recently made a false claim against 
my reputation here, I must defend myself by asking 
"hedgie" to describe that which he calls my alternative 
theory (because I have no theory, and I should be the 
first to know).

There are only two risks involved here for anyone who 
wishes to answer my simple question, viz., (i) that 
person (or persons) may not fully understand the 
question, and/or (ii) that person (or persons) may - 
as did "hedgie" - (may) come to believe that some 
alternate theory is involved due to the implications 
of my question.

It's only fair to add that my question is a very, very 
difficult one, and that "hedgie" did seem to give it 
the "old college try"; however, in my opinion, he missed 
out on the fact that a postulate in physics is a guess, 
a hunch, a supposition, a hypothesis, or a surmise about 
the nature of nature, as opposed to being (as "hedgie" 
seemed to think) a mere and purely mathematical, and 
therefore physically meaningless, axiom. The real key 
to my question is the simple fact that all physicists 
today make the claim that light's one-way speed as 
experimentally measured between two clocks located 
in the same frame is both invariant and isotropic; 
it is precisely this experiment to which my simple 
(but deep) query pertains, and it is precisely this 
same experiment to which Einstein's famous light 
postulate (aka the second postulate) pertains. 

Sincerely,
2clockdude

In the interest of fairness, and to show good will 
I will clarify my above comment, just once. 
I will not repeat  long series of clarifications of my answer,
 which were removed by editors at 2clock-dude request.
2lock-dude asks why I use word alternative:
"(because I have no theory, and I should be the first to know)..."

Standard theory assumes anisotropic space - which means that
speed of light in vacuum is constant, in all directions, 
(it is also constant forall sources).
Clock-dude considers what he calls 'anisotropic speed' which I 
take to mean that speed of light may depend on a direction.
Perhaps it does not amounts to a whole new *theory* but is certainly
is an alternative idea. Knowing what one does depends a on knowing the
terminology
http://www.math.odu.edu/~keyes/quotations/prose.html
and I admit that in few cases I had difficulty grasping meaning of his 
questions and asertions, which could be caused either by nonstandard
terminology or by unsusual septh of his thoughts.

hedgie

correction od typo

Standard theory assumes anisotropic space

should be

Standard theory assumes isotropic space

sorry about that

Hedgie

[hedgie commented:]  
   2lock-dude asks why I use word alternative:
   "(because I have no theory, and I should be the first to know)..."

  Standard theory assumes isotropic space - which means that
  speed of light in vacuum is constant, in all directions, 
  (it is also constant forall sources).
  Clock-dude considers what he calls 'anisotropic speed' which I 
  take to mean that speed of light may depend on a direction.
  Perhaps it does not amounts to a whole new *theory* but is certainly
  is an alternative idea. Knowing what one does depends a on knowing 
  the terminology
  http://www.math.odu.edu/~keyes/quotations/prose.html
  and I admit that in few cases I had difficulty grasping meaning of his 
  questions and asertions, which could be caused either by nonstandard
  terminology or by unsusual septh of his thoughts.

[2clockdude replies:]
Yes, of course standard theory "assumes" that the experimental or 
natural value of light's one-way speed is invariantly c, but the 
fact that this "assumption" (supposition, postulate, etc.) cannot 
occur in reality was the reason for my original question.

Since this was/is a never-before-raised question about Einstein's 
light postulate, it is going to be difficult to grasp at first, 
but I can assure you that the general concept is utterly simple, 
and you can see this for yourself via the following analogy:

Suppose physicist A has a theory about water's boiling point, 
and suppose that this theory is essentially the physicist's 
assumption that the natural or experimental value of the 
boiling point of water is 100 degrees. It should be clear to 
anyone (even a high school student) that physicist A in this 
case has no scientific theory because there cannot be any 
experimental or natural (or Nature-given) value for the boiling 
point of water. And the reason for this is simple: Nature cannot 
and therefore does not calibrate thermometers. Only man can do 
this. In other words, due to the inability of Nature to mark 
off or calibrate thermometers, there cannot be a law of physics 
in the boiling point of water case. Indeed, not only can there 
be one man-given (non-natural) result, but there can be an 
infinite number of such results. For example, we could set our 
thermometers so that the result is 212 degrees.

The first point of this simple analogy is the fact that if man 
must step in an control part of any physical situation, then 
the result cannot be a law of nature. 

The second point of the analogy is the fact that if there cannot 
be a law, then no experiment exists in this case.

The third point of the analogy is the fact that whenever no 
law of nature is involved, there can be no guess, hypothesis, 
assumption, conjecture, hunch, postulate, supposition, surmise, 
or even a wild stab in the dark as to what the law must be.

The fourth point of the analogy is the fact that whenever there 

can be no postulate, there can be no scientific theory.

No law --> no experiment --> no postulate --> no theory 

Now think about the one-way light speed case.

Here is a key fact:
It is impossible to measure light's one-way speed between two 
clocks (which are in the same frame) without synchronization.

Here is a related key fact:
Nature cannot synchronize clocks (just as she cannot calibrate 
thermometers).

This brings me back to my original question, which was "How 
can there be a one-way light speed postulate when no one has 
shown how to perform the one-way light speed experiment - not 
even on paper?" 

As my original query went on to helpfully explain, the above 
fact (i.e., the simple fact that no one has even shown on 
paper how to measure light's one-way speed between two same-
frame clocks) gives me a very strong hint that there simply 
is no such experiment.

As I said, I would like to know why no one can show the 
light speed experiment on paper, much less in the lab.

As I also said, since special relativity hinges entirely on 
the light postulate, it is extremely important to find out if 
there can even be such a postulate in physics. 

But all I can see is the following sequence:

No law --> no experiment --> no postulate --> no theory 

Can anyone here give me an answer that will prove that 
the "light postulate" (or Einstein's assumption of one-way 
light speed invariance) is indeed a scientific postulate?

[hedgie noted:]
  Clock-dude considers what he calls 'anisotropic speed' which I 
  take to mean that speed of light may depend on a direction.
  Perhaps it does not amounts to a whole new *theory* but is 
  certainly is an alternative idea.

But this is not merely an idea or some theoretical notion; it 
is an experimental fact. (But please bear in mind that this 
fact has nothing directly to do with my question, but was 
merely given in order to help explain why no one has ever 
used two same-frame clocks to experimentally determine the 
natural value of light's one-way speed.) For some reason, 
hedgie simply completely ignored my experimental proof of 
the variance of light's one-way speed. Since this experiment 
did not measure the value of this speed, it did not obtain 
or find the infamous natural value of it (i.e., it did not 
find the one-way, two-clock law), but the experiment instead 
merely and simply qualitatively compared two observers views 
of a passing light ray with the obvious result that they see 
it differently. 

At this point, someone may ask How can there be a round-trip 
light speed law if there cannot be a one-way law? Well, the 
answer is extremely simple: Nature fully controls both a 
clock's intrinsic rhythm and a rod's intrinsic length, unlike 
the one-way case, where Nature cannot and therefore does not 
control the clock synchronization.

Someone may ask the question How does Einstein obtain one-way 
light speed invariance? Well, the extremely simple answer is 
as follows: He merely (and baselessly) forces clocks to obtain 
his chosen value c. (He does this by sending a light ray between 
two unstarted clocks with the origin clock being started on zero, 
and with the distant clock being started on Einstein's pre-chosen 
time of x/c, no matter how long it actually took the light ray 
to reach the distant clock (which can obviously vary with the 
speed of the clock frame relative to the light source).)

Heck, if I manually force clocks to obtain a certain value 
for light's one-way speed, then they will obtain that value, 
but this is clearly a trivial and circular result, one that 
has no place in either theoretical or applied physics.

Similarly, if I manually force thermometers to read a certain 
value for water's boiling point, then they will read that value, 
but this is clearly a trivial and circular result, one that 
has no place in either theoretical or applied physics.

Please remember the key historical facts that although the 
round-trip experiment was performed decades ago, no one has 
ever performed the one-way "experiment," and not even on paper, 
so it cannot be due to a lack of technology because one can 
use perfect or ideal clocks and rulers on paper.

It is this simple historical fact that was/is the basis of my 
original question. It tells me that there is no experiment in 
the one-way case, and this in turn tells me that there is no 
law of physics in that case, which in turn tells me that there 
can be no scientific hunch or postulate pertaining to such a 
law, which in turn tells me that there can be no scientific 
theory bases on such a postulate, but I would like to hear 
from the Google answer folk the reason why no one has ever 
shown how to measure light's one-way, two-clock speed if only 
on paper.

----2clockdude----

From http://www.mountainman.com.au/news96_d.html:

To make clocks comply with his theory of relativity, Einstein manually
sets all clocks to cause them to read the same time for any one-way
light ray trip. Remember, each clock reads a different time even for a
single observer, and no other observer?s clocks will agree with any of
these, except by sheer coincidence. This is why one observer may see
two events as being simultaneous, whereas another will see the same
two events as occurring at different times. It?s all due to Einstein?s
way of setting clocks. He sets them to get c, as we have found, and
this makes them all read differently.

We therefore see that it is not really a natural law, not a law of
physics. By his own admission Einstein actually manipulates his clocks
to force the value c in the case of light?s unidirectional speed
relative to the inertial observer.

Since this is not a law, or not an experimental result at all, it is not binding.

Since nature has not (contrary to that which has been written in more
than one relativity book) dictated the value c for the one-way
lightspeed, this leaves the door wide open for other values to be
considered, at least in principle or theoretically.

Interesting question.

Thanks for your comments, keithadler.

[You wrote:] 
   "To make clocks comply with his theory of relativity, Einstein 
   manually sets all clocks to cause them to read the same time 
   for any one-way light ray trip."

This makes it sound as if a scientific theory (i.e., the "theory 
of relativity") calls for one-way invariance, when in fact there 
is no basis for it. Actually, Einstein set clocks to obtain  
one-way invariance because of the principle of relativity (PR), but, 
as is easy to see, this principle does not call for invariance in 
either the round-trip or the one-way case, but merely says that if 
and when invariance is found in one frame, then it must be found in 
all other frames. In other words, contrary to Einstein, the PR does 
not distinguish between Galileo's c ± v and Einstein's c for all. 
However, as my question pointed out, all of this is irrelevant 
because neither c ± v nor c for all can be laws of physics, so the 
principle of relativity does not pertain to either. Furthermore, 
there can be no scientific theory based on a postulate that says 
one-way invariance is the law, so special relativity cannot be a 
scientific theory.

[You wrote:] 
"Since this is not a law, or not an experimental result at all, 
it is not binding."

As I just said above, it is worse than not binding; since there 
is no one-way experiment, there is no one-way law, and since there 
is no such law, there cannot be any scientific postulate pertaining 
to such a law, and this means that there cannot be any scientific 
theory based on such a postulate.

[You wrote:] 
   "Since nature has not (contrary to that which has been written 
   in more than one relativity book) dictated the value c for the 
   one-way lightspeed, this leaves the door wide open for other 
   values to be considered, at least in principle or theoretically."

It also leaves a wide open door out of which we must boot relativity 
out as a scientific theory because there can be no natural law 
(either c or non-c) in the one-way case, which, in turn, means that 
there cannot be any scientific theory based on such a law.

And as for those "other values to be considered," actually the only 
value that has any merit is the correct value, and that can only be 
determined if man correctly synchronizes his clocks.

Yes, I know that it sounds odd to say that a correct value is not 
the law, but one must understand the difference between laws of 
nature and correct and incorrect values. For example, in the case 
of light's round-trip speed (primarily, the Michelson-Morley case), 
although the natural law was/is invariance/isotropy, this is not 
a correct result because the clock was slowed, and the rod was 
contracted. Given undistorted instruments, even light's round-trip 
speed would vary with frame velocity. This would be the correct 
result, but it would not be the round-trip law.

If you believe Maxwell's equations (and they've been tested many times
over the last century and more), then the speed of electromagnetic
radiation in a vacuum is 1/sqrt(mu0*epsilon0), where mu0 and epsilon0
are the permiability and permittivity of free space respectively.  mu0
and epsilon0 can both be measured in experiments having nothing to do
with light.

Also, while it's true that there's a difficulty in synchronizing
clocks if you're not willing to take either the speed of light or
isotropy of space as given, it is difficult to imagine a set of
physics which would allow the round-trip travel time to always give c
as the speed of light, regardless of the orientation of the
experiment, while still allowing the one-way travel time to be
something other than half of the round-trip time.  There is a symmetry
argument here: light cannot "know" whether it has just come out of a
source, or just been bounced of a mirror.  It's the same stuff either
way.  And if you imagine that there is some direction "north" in the
universe in which light travels faster than when it's going "south",
you have to wonder what could cause such a difference.  From all the
observations we've ever made, the universe is the same in every
direction.  And if this is true, it's not possible for light to "know"
whether it's going "north" or "south".

[racecar-ga noted]
If you believe Maxwell's equations....

[2clockdude replies]
Oh, we all believe them, but they are irrelevant in the 
one-way, two-clock light speed case because Maxwell used 
no clocks, much less two synchronized ones. My question 
pertains specifically to the two-clock case.

[racecar-ga went on]
Also, while it's true that there's a difficulty in synchronizing
clocks if you're not willing to take either the speed of light or
isotropy of space as given, it is difficult to imagine a set of
physics which would allow the round-trip travel time to always give c
as the speed of light, regardless of the orientation of the
experiment, while still allowing the one-way travel time to be
something other than half of the round-trip time.  There is a symmetry
argument here: light cannot "know" whether it has just come out of a
source, or just been bounced of a mirror.  It's the same stuff either
way.  And if you imagine that there is some direction "north" in the
universe in which light travels faster than when it's going "south",
you have to wonder what could cause such a difference.  From all the
observations we've ever made, the universe is the same in every
direction.  And if this is true, it's not possible for light to "know"
whether it's going "north" or "south".
 
[2clockdude replies]
This new "symmetry" argument is merely the latest urban legend re 
SR. Einstein, for example, never mentioned it. In fact, he was 
forced to force one-way isotropy and invariance by forcing clocks 
to obtain it artificially. (As I said at the start, no one has 
found this experimentally or naturally, and I claim that no one 
will ever find it naturally because it cannot occur naturally or 
experimentally. Why don't you counter my claim by at least showing 
on paper how it can be done?)

[2clockdude continues]
I need to explain to you why you said "it is difficult to imagine 
a set of physics which would allow the round-trip travel time to 
always give c as the speed of light, regardless of the orientation 
of the experiment, while still allowing the one-way travel time to 
be something other than half of the round-trip time." 
The only reason you find this difficult is that you simply do not 
understand the physics of the round-trip null results. As John 
Wheeler said, Lorentz's physical explanations of intrinsic rod 
length contraction and intrinsic clock slowing are still acceptable; 
indeed, it is impossible to show the null results on paper without 
invoking these physical Lorentzian distortions. This means that not 
even light's round-trip speed is "symmetrical," but varies with  
frame velocity, as would be found experimentally if we used UN-
distorted clocks and rods. And this means that it is - contrary 
to your above - difficult to imagine a set of physics which would 
allow one-way invariance and isotropy. 

[2clockdude continues]
Here is a very simple example of real-life one-way variance:

Refer to Einstein's train/embankment example. Take only the right-hand 
light beam. As Einstein did, let the beam start when the two observers 
meet in passing. Also as Einstein did, note that the observers will see 
the beam arrive ****differently****. (For example, the train observer 
may see the beam absolutely before the embankment observer does.) But, 
as Einstein noted, both observers will say that the beam started at 
the same frame distance away, a distance that I will call "L." And since 
the beam started at clocks in each frame which were coincident, we 
can say that it started at time zero per each frame's clock. However, 
as Einstein himself had to admit, the beam reached the observers at 
absolutely different times. (This is so because all observers in all 
frames see the beam reach the observers differently. The train observer 
was not there when the beam "hit" the embankment observer, and vice 
versa.) We can label these absolutely different beam arrival times 
"Ta" and "Tb." We can now let the observers calculate light's one-way 
speed relative to them, as follows:

Train Observer: Light's one-way speed = L/Ta

Embankment Observer: Light's one-way speed = L/Tb

It matters not what the actual values of Tb and Ta may be; all that 
matters is that Ta =/= Tb.

And if you still insist on one-way, two-clock isotropy and invariance, 
then you need to at least show how this could be proved experimentally, 
if only on paper.

----2clockdude----

You did not seem to understand point about Maxwell's equations.  In
free space, they result in a wave equation, for which the solutions
are waves traveling at speed c, which can be calculated in experiments
involving charged pith balls, coils of wire, etc.  The definition of
speed is distance/time.  So unless Maxwell's equations are wrong, the
speed of light is c, and it doesn't matter how you measure it, as long
as you do it right.  There is no need to invoke special relativity. 
There is no special formula for speed in SR.  If something goes 100
miles in 1 second, its speed is 100 miles/sec, according to Newton,
Einstein, and everyone else.

It seems to me that the kernel of substance at the center of your
question has to do with the difficulty in synchronizing clocks at
separate locations in the same frame without making any assumptions. 
Now, everything works out fine if we use the assumption that the
one-way speed of light is c.  All our experiments give the results we
expect when we use this assumption to synchronize our clocks.  That
does not prove anything, but I think it does indicate that what you
really should be asking is not 'what is the one-way speed of light?',
but instead 'what does it mean for clocks to be synchronized, and is
this concept well-defined?'.  If you are not willing to accept that
the speed of light in isotropic, then I think you must give up the
idea of there being any such thing as synchronization between two
clocks at different locations.  And perhaps you're right--it may be
that that is not an incorrect way to look at things.  But it is not
something you can prove.  If I synchronize two clocks using my
assumption, you will not be able to prove they are not synchronized,
no matter how many different experiments you come up with, unless you
make some assumption of your own.  Really, in the end, it doesn't
matter.  All that matters is that the way we think about things jives
with the results we observe.  So, for example, some people like to
think that the mass of an object increases as its speed approaches
that of light, by a factor of gamma.  Other people like to regard the
mass as constant, but they claim that the formula for momentum is
m*v*gamma.  Either way, when you do an experiment and measure
momentum, it agrees with theory.  So does the mass increase or doesn't
it?  WHO CARES??  As long as there's no experiment that can decide it
one way or another, you're free to think about it in whatever way
makes most sense to you.

"I think that a particle must have a separate reality independent of
the measurements. That is an electron has spin, location and so forth
even when it is not being measured. I like to think that the moon is
there even if I am not looking at it" according to einstein light is a
particle.think of the above and you will defenitly understand.do u
think light has mass.

[motion101 replies to racecar]

Fact 1 re Maxwell:
If Maxwell's equations really gave light's round-trip or 
one-way speed as invariantly and isotropically c, then no 
one would have predicted a positive result for the 1887 
Michelson-Morley experiment. (But every physicist firmly 
predicted a positive result.)

Fact 2 re Maxwell:
If Maxwell's equations really did give light's one-way speed 
as c invariantly and isotropically, then Einstein would not 
have had to manually force clocks in each frame to obtain this.

Fact 3 re Maxwell:
If Maxwell's equations really did give light's one-way speed 
as c invariantly and isotropically, then Einstein could not 
have derived the equation w = c - v for light's one-way speed.
(I did not say that he said that this equation is correct; I
did say that he derived it somehow, and that his derivation 
could not have happened even on paper if Maxwell's equations 
did call out for c isotropically and invariantly because the 
latter preceded Einstein's derivation.)

Fact 4 re Maxwell:
You even contradicted yourself by saying the following:
"Now, everything works out fine if we use the 
assumption that the one-way speed of light is c."
Why do we have to _assume_ it if it is given up front by 
dear old Maxwell's equations?

[racecar continued]
All our experiments give the results we expect when we use 
this assumption to synchronize our clocks.

[motion101 replies]
Not so. For example, which experiment has shown that light's 
one-way speed between two same-frame clocks is c?

[racecar continued]
If I synchronize two clocks using my assumption, you will not 
be able to prove they are not synchronized, no matter how many 
different experiments you come up with, unless you make some 
assumption of your own.

[motion101 replies]
Not so. For example, Einstein's own train example proves that 
light's one-way speed varies with frame velocity. Here's how:

Take only the right-hand light beam; as Einstein said, it started 
equidistant from each observer (per their own personal rulers in 
their own personal frames). We can label both of these equal frame 
distances L. Also, as Einstein implied, the light beam reached the 
two observers absolutely differently. (This must be an absolute 
difference because Einstein used it to derive his relativity of 
simultaneity, and no mere relative difference would be acceptable 
for that.) (Besides, it is absolute because all observers in all 
frames see that the beam reached the two observers differently; 
i.e., they see that one of the observers is *not* there when the 
beam reaches the other.) We can label these absolutely different 
beam arrival times Ta and Tb.

Thus, according to Einstein's own train example, which was used to 
derive SR, we have the following simple calculations for light's 
one-way speed in each of the two given frames:

Train Frame: Light's one-way speed = L/Ta
Embankment Frame: Light's one-way speed = L/Tb

Experiment says that your assumption is bogus.

You do not have to come up with all sorts of convoluted reasons why
Maxwell's equations cannot predict c as the speed of light in a
vacuum.  All you have to do is look at Maxwell's equations.  You can
combine them to form a wave equation for which the solutions are waves
with speed c, where c is the square root of 1/(mu_0 epsilon_0).  Do
not waste any more time arguing against it.  Just check it out.  It's
very basic physics.

>[racecar continued]
>All our experiments give the results we expect when we use 
>this assumption to synchronize our clocks.
>
>[motion101 replies]
>Not so. For example, which experiment has shown that light's 
>one-way speed between two same-frame clocks is c?

Your response here is illogical.  I claimed that all the experiments
we have done give results consistent with theory.  You state that
that's not true because no experiment has measured the one-way speed
of light.  If you cannot see that the fact that a certain experiment
has not been done does not contradict my statement, then this is
hopeless.

You have never explained the exact setup for your 'train experiment'
so it's not easy to figure out exactly what your misconception is.  As
far as I can tell, it is that both observers see the light source as
being the same distance away when they pass, which they don't because
of length contraction.

It is not at all annoying when physics amateurs ask question in order
to try to understand physics better.  It is annoying when they
willfully reject physical theories without a sound understanding.

[racecar wrote] 
You do not have to come up with all sorts of convoluted reasons 
why Maxwell's equations cannot predict c as the speed of light 
in a vacuum.

[motion101 replies]
None of the reasons were "convoluted."
Tell us how Maxwell's equations "predict" that light's 
one-way speed per two same-frame clocks is invariant.

[motion101 continues]
And while you are at it, bear in mind that such a speed  
cannot possibly be measured without clock synchronization, 
so you must include how Maxwell synchronized his clocks.

-----

[racecar wrote] 
All our experiments give the results we expect when we use 
this assumption to synchronize our clocks.

[motion101 replied]
Not so. For example, which experiment has shown that light's 
one-way speed between two same-frame clocks is c?

[racecar replied]
Your response here is illogical.  

[motion101 replies]
No, it was logical because it shows that the basis for all 
"experiments" in SR is invalid, and that basis was/is the 
second "postulate," which tries to claim that light's one-way 
speed between two same-frame clocks is invariant.

[motion101 continues] Read my lips:
All measurements (and therefore all "experimental" results) 
in SR are based on the use of clocks which have been related 
temporally per Einstein's synchronization definition, which, 
in turn, was/is based on his utterly baseless second "postulate." 
Therefore, no SR "experiments" give any valid results because 
the second postulate itself is invalid. 

[motion101 continues]
For example, SR's "time dilation" has nothing to do with a 
clock's intrinsic atomic rhythm, but has everything to do 
with outside observers' viewpoints of the clock as it 
passes them. Such viewpoint effects are of no more importance 
to space-time physics than are things such as the apparent 
shortening of two departing observers as seen by each other.

-----

[racecar wrote] 
You have never explained the exact setup for your 'train experiment'
so it's not easy to figure out exactly what your misconception is.  
As far as I can tell, it is that both observers see the light source 
as being the same distance away when they pass, which they don't 
because of length contraction.

[motion101 replies]
You failed to pay attention. I said up front that I was simply using 
Einstein's train example. What do you not understand about Einstein's 
train example?

-------

[racecar wrote] 
It is not at all annoying when physics amateurs ask question in order
to try to understand physics better.  It is annoying when they
willfully reject physical theories without a sound understanding.

[motion101 replies]
I claim that SR's clocks are incorrectly related temporally.
Can you prove otherwise?
If not, then all SR results are incorrect, including the basis 
of SR, Einstein's "light postulate."
It is very annoying when some inattentive person thinks he 
knows everything about SR, but knows practically nothing.

Einstein used many train examples in his writings.  It wouldn't hurt
to explain which one you're thinking of.  It sounds like you mean one
he used to demonstrate the relativity of simultaneity, but if so,
you're quoting it wrong.  The light signals from the two sources
arrive at both the train observer and the platform observer when they
pass.  The signals do not, as you claim, start then.  Since they start
at different locations, there's no unambiguous meaning of the word
'then' in the previous sentence anyway.  You would have to choose a
reference frame.  But in the example I think you're referring to, the
signals both arrive at the observers as they pass each other, and all
observers in all frames will agree on this.  From the example, you can
see that, though the signals started simultaneously in the platform
frame, the one ahead of the train started first in the train frame. 
There are no inconsistencies or flaws in SR demonstrated by this
example.  And as I said before, no experiment has ever contradicted
SR, so even if you'd like to regard SR as unproven, you have no reason
to doubt its predictions.  If a theory correctly predicts the results
of any experiment you can come up with, it's a good theory.

I repeat for the third time that Maxwell's equations predict that the
speed of light is c in a vacuum.  And, I do NOT have to tell you how
Maxwell synchronized his clocks.  I did not say Maxwell measured the
speed of light, I said that his equations predicted it.

Here are his equations, for space with no current, no charge, and no matter:

1)   div E = 0
2)   div B = 0
3)   curl E = -dB/dt
4)   curl B = (mu_0)(epsilon_0)dE/dt

Taking the curl of 3 and 4, and applying 1 and 2, we get:

del^2 E = (mu_0)(epsilon_0)d^2E/dt^2
del^2 B = (mu_0)(epsilon_0)d^2B/dt^2

Well what the hell do you know.  It's an electromagnic wave with speed c.

As for me knowing nothing, I wonder what they were thinking when they
gave me A's in those classes on special and general relativity, when
they graduated me in the top tenth of my class from a top US
university with a degree in physics, wonder how I got a perfect score
on the physics GRE.

Keep trying, once you give up the idea that Einstein was wrong, you'll
eventually figure it out.  Now I'm through wasting my time.

[motion101 to "citson" or "racecar" or whomever]
Let's see if you can follow instructions:

STEP ONE:
Go to this web site:
http://www.bartleby.com/173/7.html
  
STEP TWO:
Scroll down to Einstein's math equation w = c - v.

STEP THREE:
Show on paper how the equation was derived.

(Ignore the fact that Einstein claimed that this 
math result conflicted with some principle.)

I predict that you will drop this ball rapidly.