Sagnac & relativity
Mark Samokhvalov
Sagnac & relativity
In this group I recently found statements to the effect that the Sagnac
experiment was explained and even predicted (sic!) by SR. I have perused
many books on relativity dating back to 1920, including Einstein's, and saw
no mention of Sagnac, until I came across a textbook by M.-A.Tonnella on
magnetism and relativity ('55?), where a GR explanation of it was
presented.
I have the following questions to relativity fans:
1. Do you agree, that, if two waves radiated at the same point return to
that point with an accumulated phase difference, this means that there is a
difference in either their:
a) paths, or
b) phase velocities?
Or, perhaps, you can suggest another possibility?
2. When, as in Sagnac experiment, two waves are made to travel in opposite
directions along the same path (typically, an optical filament), does this
path in some mysterious way become, in the course of the ring's rotation,
different for the clock-wise and the anti-clockwise waves?
3. If not, how, with the phase velocity being equal for both waves, can a
phase difference accumulate?
Thanks for the answers.
Dennis McCarthy
>directions along the same path (typically, an optical filament), does this
>path in some mysterious way become, in the course of the ring's rotation,
>different for the clock-wise and the anti-clockwise waves?
Dennis: You may not believe this, but that is precisely the relativist
argument. Heck, people accepted the Copenhagen interpretation for decades, why
not that a path is longer clockwise than counter-clockwise? There is simply no
limit or boundary to what people are willing to believe in defense of certain
theories.
Dennis McCarthy
Stephen
<samokh...@mtu-net.ru> wrote:
> Sagnac & relativity
>
> In this group I recently found statements to the effect that the Sagnac
> experiment was explained and even predicted (sic!) by SR. I have perused
> many books on relativity dating back to 1920, including Einstein's, and saw
> no mention of Sagnac, until I came across a textbook by M.-A.Tonnella on
> magnetism and relativity ('55?), where a GR explanation of it was
> presented.
> I have the following questions to relativity fans:
> 1. Do you agree, that, if two waves radiated at the same point return to
> that point with an accumulated phase difference, this means that there is a
> difference in either their:
> a) paths, or
> b) phase velocities?
> Or, perhaps, you can suggest another possibility?
> 2. When, as in Sagnac experiment, two waves are made to travel in opposite
> directions along the same path (typically, an optical filament), does this
> path in some mysterious way become, in the course of the ring's rotation,
> different for the clock-wise and the anti-clockwise waves?
If you look at the path in an inertial frame (in which the speed of
light going round the ring is c) it's clear that, as the ring is rotating,
a light beam travelling in the direction of rotating has to travel further
than one travelling against the direction of rotation in order to return
to the point on the ring from which they were emitted. I would not
describe that as 'mysterious' but rather as 'obvious'.
--
Felix qui potuit rerum cognoscere causas - Virgil.
sh...@my-deja.com
> Sagnac & relativity
>
> In this group I recently found statements to the effect that the
> Sagnac experiment was explained and even predicted (sic!) by SR. I
> have perused many books on relativity dating back to 1920, including
> Einstein's, and saw no mention of Sagnac, until I came across a
> textbook by M.-A.Tonnella on magnetism and relativity ('55?), where
> a GR explanation of it was presented.
> I have the following questions to relativity fans:
> 1. Do you agree, that, if two waves radiated at the same point return
> to that point with an accumulated phase difference, this means that
> there is a difference in either their:
> a) paths, or
> b) phase velocities?
> Or, perhaps, you can suggest another possibility?
> 2. When, as in Sagnac experiment, two waves are made to travel in
> opposite directions along the same path (typically, an optical
> filament), does this path in some mysterious way become, in the
> course of the ring's rotation, different for the clock-wise and
> the anti-clockwise waves?
> 3. If not, how, with the phase velocity being equal for both waves,
> can a phase difference accumulate?
> Thanks for the answers.
SR predicts the Sagnac effect quite easily, and here's a beautiful
derivation and explanation:
http://mathpages.com/rr/s2-07/2-07.htm
1a) yes, different path lengths
2) no mystery needed, a rotating frame is non-inertial
---Tim Shuba---
Sent via Deja.com http://www.deja.com/
Before you buy.
sh...@my-deja.com
> > When, as in Sagnac experiment, two waves are made to travel in
> > opposite directions along the same path (typically, an optical
> > filament), does this path in some mysterious way become, in the
> > course of the ring's rotation, different for the clock-wise and
> > the anti-clockwise waves?
>
> Dennis: You may not believe this, but that is precisely the
> relativist argument. Heck, people accepted the Copenhagen
> interpretation for decades, why not that a path is longer
> clockwise than counter-clockwise? There is simply no
> limit or boundary to what people are willing to believe
> in defense of certain theories.
No limit? Yes indeed Mr Sophist. How many dozens of posts have
you made about Sagnac? SR's explanation is simple and consistent.
See http://mathpages.com/rr/s2-07/2-07.htm for an explanation
that includes the exact reason why the Sagnac effect is perfect
fodder for your sophistry. Note especially the last paragraph.
Dennis McCarthy
Dennis: Unfortunately, here's the problem:
"Still, the doubter imagines that we can transform this bias away, by treating
the situation with respect to coordinates that are rigidly attached to and
rotating along with the device. Surely (he reasons) we can regard the paths of
the two light beams as spatially congruent and equal as seen from this system
of reference, and so the asymmetric travel times must imply anisotropic light
speed with respect to these coordinates. This is actually true, in the sense
that it's possible to define a system of coordinates in terms of which the
positions of the points on the disk are independent of the time coordinate, but
of course such coordinates are necessarily accelerating (viz., rotating), and
special relativity does not assume light speed to be isotropic with respect to
non-inertial coordinates."
That's called the "naive" SR explanation. Allowing anisotropy wrt the
non-inertial rim observer results in the Selleri paradox.
If you want the correct SR explanation, check Rizzi and Tartaglia's.
You'll find it's not so simple. And you'll find that the explanation does in
fact involve that " this path in some mysterious way become, in the course of
the ring's rotation, different for the clock-wise and
the anti-clockwise waves"--even for the rim observer.
Dennis McCarthy
Dennis McCarthy
>
>> Sagnac & relativity
>>
>> In this group I recently found statements to the effect that the Sagnac
>> experiment was explained and even predicted (sic!) by SR. I have perused
>> many books on relativity dating back to 1920, including Einstein's, and saw
>> no mention of Sagnac, until I came across a textbook by M.-A.Tonnella on
>> magnetism and relativity ('55?), where a GR explanation of it was
>> presented.
>> I have the following questions to relativity fans:
>> 1. Do you agree, that, if two waves radiated at the same point return to
>> that point with an accumulated phase difference, this means that there is a
>> difference in either their:
>> a) paths, or
>> b) phase velocities?
>> Or, perhaps, you can suggest another possibility?
>> directions along the same path (typically, an optical filament), does this
>> path in some mysterious way become, in the course of the ring's rotation,
>> different for the clock-wise and the anti-clockwise waves?
>
>light going round the ring is c) it's clear that, as the ring is rotating,
>a light beam travelling in the direction of rotating has to travel further
>than one travelling against the direction of rotation in order to return
>to the point on the ring from which they were emitted. I would not
>describe that as 'mysterious' but rather as 'obvious'.
Dennis: Ahh, so you think it is "obvious" that when you move at a light beam,
it approaches you faster than when you move away from it?
I agree that that is obvious, but you wouldn't believe that some people try to
deny it.
Dennis McCarthy
Dennis McCarthy
>derivation and explanation:
>
>http://mathpages.com/rr/s2-07/2-07.htm
>
>1a) yes, different path lengths
>
>2) no mystery needed, a rotating frame is non-inertial
D: Sorry. 1) The path lengths aren't different to a person on the rim.
2) The non-inertial fall back has been rejected by mainstream physicists.
Check Rizzi and Tartaglia's explanation for the correct SR version.
Dennis McCarthy
Paul Stowe
>light going round the ring is c) it's clear that, as the ring is
rotating,
>a light beam travelling in the direction of rotating has to travel
further
>than one travelling against the direction of rotation in order to
return
>to the point on the ring from which they were emitted. I would not
>describe that as 'mysterious' but rather as 'obvious'.
Geez, we agree. What a shocker...
Paul Stowe
Standeven
Mark Samokhvalov wrote:
> Sagnac & relativity
>
> In this group I recently found statements to the effect that the Sagnac
> experiment was explained and even predicted (sic!) by SR. I have perused
> many books on relativity dating back to 1920, including Einstein's, and saw
> no mention of Sagnac, until I came across a textbook by M.-A.Tonnella on
> magnetism and relativity ('55?), where a GR explanation of it was
> presented.
> I have the following questions to relativity fans:
> 1. Do you agree, that, if two waves radiated at the same point return to
> that point with an accumulated phase difference, this means that there is a
> difference in either their:
> a) paths, or
> b) phase velocities?
> Or, perhaps, you can suggest another possibility?
It could be their frequencies which differ.
> 2. When, as in Sagnac experiment, two waves are made to travel in opposite
> directions along the same path (typically, an optical filament), does this
> path in some mysterious way become, in the course of the ring's rotation,
> different for the clock-wise and the anti-clockwise waves?
> 3. If not, how, with the phase velocity being equal for both waves, can a
> phase difference accumulate?
What makes you think that the phase velocity is equal for the two waves?
You're not in an inertial frame...
Tom Roberts
> In this group I recently found statements to the effect that the Sagnac
> experiment was explained and even predicted (sic!) by SR.
It is easily explained by SR. I do not think it was predicted by
any SR advocate before Sagnac performed his experiment (but I am
not an expert on such historical questions).
> 1. Do you agree, that, if two waves radiated at the same point return to
> that point with an accumulated phase difference, this means that there is a
> difference in either their:
> a) paths, or
> b) phase velocities?
> Or, perhaps, you can suggest another possibility?
There could be a difference in the gravitational potential
integrated along their paths. There could be different optical
media in their paths, or media moving differently (but are these
differences in path?). There are probably other possibilities....
> 2. When, as in Sagnac experiment, two waves are made to travel in opposite
> directions along the same path (typically, an optical filament), does this
> path in some mysterious way become, in the course of the ring's rotation,
> different for the clock-wise and the anti-clockwise waves?
This depends upon what coordinates (aka reference frame) you use to
describe it. Note that both speed and spatial path length are
inherently coordinate dependent.
Let me assume the center of rotation of the ring interferometer is
at rest in an inertial frame. In this frame SR predicts the speed
of light is isotropically c; in this frame it is clear that the
co-rotating and counter-rotating light rays travel different
distances. So there is no mystery -- the light rays travel
different distances at the same speed and therefore accumulate a
phase difference.
One might also describe this in coordinates rotating with the
ring interferometer. In these coordinates the _average_ speed
of light _going_all_the_way_around_the_ring_ is different for
the two directions, but the distance is the same for both rays.
Again there is no mystery -- the light rays travel the same
distance at different average speeds and therefore accumulate
a phase difference.
Note that it is tricky to define "speed of light"
in these coordinates, but there is indeed a well-defined
_average_ speed of light _going_all_the_way_around_.
This is intimitely related to the difficulty of
synchronizing clocks in a rotating system....
One could also describe this in the inertial frame which is
co-moving with the emitter/detector when the rays are emitted
(think of very short pulses of light). Note that the emitter/
detector moves (slightly) in this frame while the rays are in
transit. In this frame the speed of light is isotropically c,
and the two paths the rays follow are distorted circles which
are not congruent, and which have different lengths. Again
there is no mystery -- the light rays travel different
distances at the same speed and therefore accumulate a phase
difference.
One could also choose any other inertial frame. Again the
conclusion is that the light rays travel different distances
at the same speed and therefore accumulate a phase difference.
> 3. If not, how, with the phase velocity being equal for both waves, can a
> phase difference accumulate?
See above. Like so many things, one can consider it in several
different ways, and one's description/explanation will be
different for different viewpoints. And as always, one must
use a single viewpoint (coordinate system) for the entire
analysis.
This latter seems to be the problem in your question, in
which you appear to switch between the co-rotating frame
and an inertial frame. You seem to (implicitly) think
that SR implies that the speed of light in the rotating
system will be isotropically c -- that is _NOT_ true.
Your "same path" is true only in the rotating system,
and you clearly mean same _spatial_ path (in spacetime
there is no way to consider the two rays as following
the same path -- they are helices of opposite twist
and different path length).
Tom Roberts tjro...@lucent.com
Robert Chan
>>See http://mathpages.com/rr/s2-07/2-07.htm for an explanation
>>that includes the exact reason why the Sagnac effect is perfect
>>fodder for your sophistry. Note especially the last paragraph.
>Dennis: Unfortunately, here's the problem:
>
>non-inertial coordinates."
>
>That's called the "naive" SR explanation...
As usual, Dennis is quite wrong about this. I checked the referenced
web page, and the very next paragraph after the one Dennis quotes says
"There are, however, some interesting issues raised by
accelerating coordinate systems, but we'll defer discussion
of those until Section 4.5. For the moment, let's just confine
our attention to inertial coordinates, and show how a Sagnac
device appears in terms of the co-moving inertial frame of
an arbitrary point on the perimeter."
It then goes on to describe the Sagnac effect for a range of inertial
coordinates, and then in Section 4.5 discusses the same thing with
respect to accelerated (rotating) coordinates.
On 07 Mar 2000 23:01:21 GMT, djm...@aol.com (Dennis McCarthy) wrote:
> Allowing anisotropy wrt the non-inertial rim observer results
> in the Selleri paradox.
Just so no one is misled by this, Dennis is referring to a silly
mistake by Selleri that was thoroughly debunked in this newsgroup
a year or two ago. Check deja news. In summary, the Sagnac effect
remains proportional to the amount of ANGULAR travel, i.e., rotation,
during the transit of the light, even in the limit as the radius R
of the device goes to infinity.
On 07 Mar 2000 23:01:21 GMT, djm...@aol.com (Dennis McCarthy) wrote:
>If you want the correct SR explanation, check Rizzi and Tartaglia's.
>You'll find it's not so simple.
In terms of accelerating coordinates, very few physical phenomena
can be described simply - which is why we seldom use accelerating
coordinates when we can avoid it (as we certainly can in this case).
The explanation given by Rizzi and Tartaglia for accelerating
coordinates is similar to the explanation given in Section 4.5
of the web page referenced above.
>And you'll find that the explanation does in fact involve that
>"this path in some mysterious way becomes, in the course of
>the ring's rotation, different for the clock-wise and the
>anti-clockwise waves"--even for the rim observer.
Again, just so no one is misled, Dennis is completely incorrect in
his assessment. There is nothing mysterious about accelerating
coordinate systems, at least not to anyone who understands them.
Mark Samokhvalov
Tom Roberts пишет в сообщении <38C5C242...@chicago.avenew.com> ...
>Mark Samokhvalov wrote:
>> In this group I recently found statements to the effect that the Sagnac
>> experiment was explained and even predicted (sic!) by SR.
>
>It is easily explained by SR. I do not think it was predicted by
>any SR advocate before Sagnac performed his experiment (but I am
>not an expert on such historical questions).
>
>
>> 1. Do you agree, that, if two waves radiated at the same point return to
>> that point with an accumulated phase difference, this means that there is
a
>> difference in either their:
>> a) paths, or
>> b) phase velocities?
>> Or, perhaps, you can suggest another possibility?
>
>There could be a difference in the gravitational potential
>integrated along their paths. There could be different optical
>media in their paths, or media moving differently (but are these
>differences in path?).
Yes, they are differences in optical paths.
>There are probably other possibilities..
Are there?
.
>
>
>> 2. When, as in Sagnac experiment, two waves are made to travel in
opposite
>> directions along the same path (typically, an optical filament), does
this
>> path in some mysterious way become, in the course of the ring's rotation,
>> different for the clock-wise and the anti-clockwise waves?
>
>This depends upon what coordinates (aka reference frame) you use to
>describe it. Note that both speed and spatial path length are
>inherently coordinate dependent.
That was my slip. I thought, those informed knew, the problem existed only
in the rotating RF. In a RF at rest wrt ether, SR = LET.
>
>Let me assume the center of rotation of the ring interferometer is
>at rest in an inertial frame. In this frame SR predicts the speed
>of light is isotropically c; in this frame it is clear that the
>co-rotating and counter-rotating light rays travel different
>distances. So there is no mystery -- the light rays travel
>different distances at the same speed and therefore accumulate a
>phase difference.
Exactly. Here SR = LET.
>One might also describe this in coordinates rotating with the
>ring interferometer. In these coordinates the _average_ speed
>of light _going_all_the_way_around_the_ring_ is different for
>the two directions, but the distance is the same for both rays.
>Again there is no mystery -- the light rays travel the same
>distance at different average speeds and therefore accumulate
>a phase difference.
You are a poor relativist: GR insists: in ALL RF the locally measured
velocity of light is isotropic and = c.
>
> Note that it is tricky to define "speed of light"
> in these coordinates, but there is indeed a well-defined
> _average_ speed of light _going_all_the_way_around_.
> This is intimitely related to the difficulty of
> synchronizing clocks in a rotating system....
There's no such problem in this case with the point of emission coinciding
with the point of reception.
The whole story reminds me of a Russian anecdote: Contributions were invited
to a conference on new methods in surgery, and one was submitted by an
Armenian team entitled "A New Method of Tonsilectomy". "Could anything be
new in that traditional method?" - "Ah, but you don't know, how we perform
it - we do it thtough the ass hole!" (Armenians in Russia are believed to
have homosexual preferemces.)
J.Bielawski
Dennis McCarthy <djm...@aol.com> wrote in message
news:20000307180426...@ng-cb1.aol.com...
> >SR predicts the Sagnac effect quite easily, and here's a beautiful
> >derivation and explanation:
> >
> >http://mathpages.com/rr/s2-07/2-07.htm
> >
> >1a) yes, different path lengths
> >
> >2) no mystery needed, a rotating frame is non-inertial
>
> D: Sorry. 1) The path lengths aren't different to a person on the rim.
The previous poster was referring to the inertial lab system.
> 2) The non-inertial fall back has been rejected by mainstream physicists.
Nonsense.
> Check Rizzi and Tartaglia's explanation for the correct SR version.
They didn't investigate the matter fully because their main concern
was Selleri's paradox. In fact noninertial frames work here just fine.
Luc Bourhis
>
> Sagnac & relativity
>
> many books on relativity dating back to 1920, including Einstein's, and saw
> no mention of Sagnac, until I came across a textbook by M.-A.Tonnella on
> magnetism and relativity ('55?), where a GR explanation of it was
> presented.
A very good reference which analyzes many aspects of the problem,
considering relativistic as well as non-relativistic Sagnac, is [1]. A
pedagogical treatment can also be found in [2] for light Sagnac. A
presentation of the experiments based on light can be found in [3]. For
the experiments using neutrons, see [5].
> I have the following questions to relativity fans:
> 1. Do you agree, that, if two waves radiated at the same point return to
> that point with an accumulated phase difference, this means that there is a
> difference in either their:
> a) paths, or
> b) phase velocities?
> Or, perhaps, you can suggest another possibility?
> 2. When, as in Sagnac experiment, two waves are made to travel in opposite
> directions along the same path (typically, an optical filament), does this
> path in some mysterious way become, in the course of the ring's rotation,
> different for the clock-wise and the anti-clockwise waves?
> 3. If not, how, with the phase velocity being equal for both waves, can a
> phase difference accumulate?
As many people, you consider that defining the length of co- and
counter-rotating light rays or the length of the rim itself is a trivial
question. It is not the case at all. Indeed the naive notion of length
require your being able to consider the whole rim or the whole rays at a
given instant. But it can be proved that it is impossible to realize
coherently such a "space + time splitting" because it is impossible to
devise an unambiguous global synchronisation procedure on the whole
ring. I will not give this demonstration because it is too complicated
to expose it in ASCII. The interesting reader is refered to [4] and
references therein.
However, just to give you a flavour of the issue, let's consider the
following a priori straightforward situation: two particles are sent
from some point A on the rim, in opposite directions, with the *same
speed V with respect to the rim*. According to a clock at A, SR predicts
that they do not come back at the same time ! This time delay T between
the two arrivals (which does not depend on V) is observed experimentally
in neutron experiments as a phase shift [5] between the wave functions
of these particles (the experimental configuration is not exactly the
one I described but it is close enough for my example to be relevant).
Now consider two slow moving clocks C+ and C-, respectively co- and
counter-rotating. If they are synchronized with a clock at point A, when
they come back to A, C+ and C- are respectively late and ahead with
respect to A and the difference between their reading is exactly the
above time delay T.
This shows clearly that there is much more than a speed anisotropy at
work in Sagnac experiments, even if an etherist might believe at first
that it is a possible explanation for Sagnac experiments based on light
propagation.
[1] J. Anandan, Phys. Rev. D, Vol. 24, N. 2, (1981) 338
[2] G. Rizzi, A. Tartaglia, gr-qc/9805089
[3] E.J. Post, Rev. Mod. Phys., Vol. 39, N. 2 (1967) 475
[4] V. Cantoni, Il Nuovo Cimento, Vol. 57 B, N. 1 (1968) 220
[5] S.A. Werner et al, Phys. Rev. A 21 (1980) 1419
--
Luc Bourhis
Center for Particle Theory
University of Durham, UK
Dennis McCarthy
>On 07 Mar 2000 23:01:21 GMT, djm...@aol.com (Dennis McCarthy) wrote:
>>>See http://mathpages.com/rr/s2-07/2-07.htm for an explanation
>>>that includes the exact reason why the Sagnac effect is perfect
>>>fodder for your sophistry. Note especially the last paragraph.
>>Dennis: Unfortunately, here's the problem:
>>
>>"Still, the doubter imagines... isotropic with respect to
>>non-inertial coordinates."
>>
>>That's called the "naive" SR explanation...
>
Dennis: Hmmm. First post to me and already sets the tone. Couldn't you have
been more polite?
Rchan: I checked the referenced
>web page, and the very next paragraph after the one Dennis quotes says
>
> "There are, however, some interesting issues raised by
> accelerating coordinate systems, but we'll defer discussion
> of those until Section 4.5. For the moment, let's just confine
> our attention to inertial coordinates,
Dennis: That paragraph I quoted does not confine its "attention to inertial
coordinates." Instead, it states "but
of course such coordinates are necessarily accelerating (viz., rotating), and
special relativity does not assume light speed to be isotropic with respect to
non-inertial coordinates."
Are you arguing that it is theoretically acceptable for the SR explanation to
assume that the speed of light is non-isotropic for the rim observer?
>On 07 Mar 2000 23:01:21 GMT, djm...@aol.com (Dennis McCarthy) wrote:
>> Allowing anisotropy wrt the non-inertial rim observer results
>> in the Selleri paradox.
>
Rchan: >Just so no one is misled by this, Dennis is referring to a silly
>mistake by Selleri that was thoroughly debunked in this newsgroup
>a year or two ago.
Dennis: Um, the only "mistake" of Selleri that was *alleged* by R&T was that
the paradox negates the SR view. However, R&T use the Selleri Paradox to
actually *refute* the naive SR position which states that the velocity of light
is anisotropic wrt the rim observer. Instead, they retrieve an explanation for
SR by *avoiding* the Selleri Paradox.
>On 07 Mar 2000 23:01:21 GMT, djm...@aol.com (Dennis McCarthy) wrote:
>>If you want the correct SR explanation, check Rizzi and Tartaglia's.
>>You'll find it's not so simple.
>
>In terms of accelerating coordinates, very few physical phenomena
>can be described simply
Dennis: Sagnac and Michelson did it in a few lines of algebra. According to
the rim observer, the speed of light is c+/-v. Not too hard.
D:>>And you'll find that the explanation does in fact involve that
>>"this path in some mysterious way becomes, in the course of
>>the ring's rotation, different for the clock-wise and the
>>anti-clockwise waves"--even for the rim observer.
>
Rchan: >Again, just so no one is misled, Dennis is completely incorrect in
>his assessment. There is nothing mysterious about accelerating
>coordinate systems, at least not to anyone who understands them.
Dennis: Are you trying to argue that R&T's position regarding the Sagnac effect
was *not* that the "path becomes, in the course of the ring's rotation,
different for the clock-wise and the
anti-clockwise waves"--even for the rim observer?
Dennis McCarthy
Dennis McCarthy
>
Dennis: Well, you know yourself that R&T do argue that the notion that the
speed of light is anisotropic wrt a rim observer is a problem for SR.
>> Check Rizzi and Tartaglia's explanation for the correct SR version.
>
JB: >They didn't investigate the matter fully because their main concern
>was Selleri's paradox. In fact noninertial frames work here just fine.
Dennis: R&T figured it out for the rim observer, i.e., a non-inertial frame.
And you are right that such frames "work just fine"--if you manage to deduce
the fact that the length of the path is different clockwise than
counter-clockwise wrt a rim observer. To me, that seems somewhat artificial.
I would rather trust the rulers of the rim observer, wouldn't you?
Dennis McCarthy
Dennis McCarthy
>the two directions, but the distance is the same for both rays.
>Again there is no mystery -- the light rays travel the same
>distance at different average speeds and therefore accumulate
>a phase difference.
Dennis: Interestingly, the average speed of light for the trip is not the
average of all the speeds for each small segment of the trip. Anyway, R&T
rejected such explanations via Selleri years ago.
Allegedly, according to the rim observer, the speed of light is still
anisotropic--despite what his rulers and clock reads.
Roberts: Note that it is tricky to define "speed of light"
> in these coordinates,
Dennis: Not for etherists.
but there is indeed a well-defined
> _average_ speed of light _going_all_the_way_around_.
> This is intimitely related to the difficulty of
> synchronizing clocks in a rotating system....
Dennis: No difficulty for etherists.
Dennis McCarthy
Tom Roberts
> Tom Roberts wrote:
> >One might also describe this in coordinates rotating with the
> >ring interferometer. In these coordinates the _average_ speed
> >of light _going_all_the_way_around_the_ring_ is different for
> >the two directions, but the distance is the same for both rays.
> >Again there is no mystery -- the light rays travel the same
> >distance at different average speeds and therefore accumulate
> >a phase difference.
> velocity of light is isotropic and = c.
Yes, _LOCALLY_. That's why I explicitly said "_AVERAGE_ speed".
Going all the way around the ring in these rotating cooridnates is
not a local measurement, and there is no constraint on the speed
of light for such non-local measurements.
> > Note that it is tricky to define "speed of light"
> > in these coordinates, but there is indeed a well-defined
> > _average_ speed of light _going_all_the_way_around_.
> > This is intimitely related to the difficulty of
> > synchronizing clocks in a rotating system....
> There's no such problem in this case with the point of emission coinciding
> with the point of reception.
Yes. As I was at pains to point out, the _AVERAGE_ speed _GOING_
_ALL_THE_WAY_AROUND_ is well defined. This is so because one can
measure this average speed with a single clock, and the difficulties
of clock synchronization do not arise. But for any other situation
(other than average speed around a closed path) one does indeed need
to synchronize clocks to measure the speed of light, and those
difficulties arise....
Tom Roberts tjro...@lucent.com
Tom Roberts
> Dennis: Interestingly, the average speed of light for the trip is not the
> average of all the speeds for each small segment of the trip.
Yes. Because global properties can be different from local properties.
Note that the procedures used to measure the speed of light on those
individual small segments are _different_ from both each other and
from the procedure used to measure the average, so it's not too
surprising that the results are different: each segment must
synchronize clocks differently, but the average needs no clock
synchronization at all (it's a single-clock measurement).
> Anyway, R&T
> rejected such explanations via Selleri years ago.
Selleri made a different mistake -- he claimed (incorrectly) that
in the limit R->infinity his rotating example showed an anisotropic
local speed of light. His error was that to obtain this result he
used clocks synchronized in a differrent frame from the one in which
he measured the distance travelled. That's a common undergraduate
mistake....
To the mystified onlookers: "R&T" refers to Rizzi and
Tartaglia's preprints gr-qc/9805089 and gr-qc/9904028.
In essence they show that in the rotating system the sum of
the rulers laid around the rotating rim does not measure the
_spatial_ distance around the rim, it measures distance
along a helix which does not lie in any purely spatial
3-space; when one projects this onto a purely spatial
3-space, one obtains isotropy for the speed of light in the
rotating system.
This is directly related to my comments elsewhere that this
system is _ambiguous_ -- one can select many different but
individually self-consistent coordinates to describe this.
I discussed 4 different coordinates in my post, R&T use
still different coordinates....
> Allegedly, according to the rim observer, the speed of light is still
> anisotropic--despite what his rulers and clock reads.
When you insist on making such poorly-worded statements it's no
surprise that your statements contain internal contradictions, and
you get confused.
First, I suspect you intended to say "isotropic" rather than
"anisotropic" there. But it really doesn't matter. The thing you are
missing is the distinction between a local measurement and a non-local
measurement, and the different procedures used to make them in this
case.
One can take the sum of the rulers laid around the rotating rim and
divide it by the time taken for a light pulse to circumnavigate the
rim (measured on a single clock). This is clearly an _average_
mesurement. But as R&T showed, this is not really "distance"/"time",
this is really "distance plus an admixture of time"/"time", and
calling it "speed" is really a misnomer.
Tom Roberts tjro...@lucent.com
Tom Roberts
> [1] J. Anandan, Phys. Rev. D, Vol. 24, N. 2, (1981) 338
> [2] G. Rizzi, A. Tartaglia, gr-qc/9805089
> [3] E.J. Post, Rev. Mod. Phys., Vol. 39, N. 2 (1967) 475
> [4] V. Cantoni, Il Nuovo Cimento, Vol. 57 B, N. 1 (1968) 220
> [5] S.A. Werner et al, Phys. Rev. A 21 (1980) 1419
More recent experiments:
Anderson et al, Am. J. Phys. 62#11 (1994), p975.
A more recent review, and description of a much more accurate
ring interferometer.
Hasselbach and Nicklaus, Phys. Rev. A 48#1 (1993), p143.
The Sagnac effect using electrons.
Allan et al, Science, 228 (1985), p69.
They observed the Sagnac effect using GPS satellite signals
observed simultaneously at multiple locations around the world.
Other possibly interesting articles (theory) are:
Gron, "Relativistic description of a Rotating Disk", AJP 43#10 (1975),
p869.
Mainwaring and Stedman, "Accelerated Clock Principles in Special
Relativity:, Phys. Rev. A47#5 (1993), p3611.
Berenda, "The Problem of the Rotating Disk", Phys. Rev. 62 (1942), p280.
Ashtekar and Magnon, "The Sagnac Effect in General Relativity", J. Math.
Phys. 16#2 (1975), p341.
BTW Sagnac's original papers are:
Sagnac, C.R.A.S 157 (1913), p708, p1410; J. Phys. Radium, 5th Ser.
4 (1914), p177.
Tom Roberts tjro...@lucent.com
Dennis McCarthy
>Dennis McCarthy wrote:
>> Dennis: Interestingly, the average speed of light for the trip is not the
>> average of all the speeds for each small segment of the trip.
>
properties.
Dennis: But what's astounding is that the global properties (the whole) does
not equal the sum of the local properties (the parts.) This, of course, is a
newly invented, complicated, counter-intuitive and bizarre principle--that must
be believed on faith--in order to maintain allegiance to SR.
The sound Sagnac explanation and the medium Sagnac explanation in general has
no such problems.
Roberts: >Note that the procedures used to measure the speed of light on those
>individual small segments are _different_ from both each other
Dennis: You are claiming that c as the local speed of light is the *reality* of
the underlying situation. The real speed of the local speeds of light does not
add up to average global speed--according to you.
If you are arguing that a measured local speed of c is just an artifact of the
method of measurement (ie, Einstein synch procedures) then we are agreed.
>> Anyway, R&T
>> rejected such explanations via Selleri years ago.
>
Roberts: >Selleri made a different mistake -- he claimed (incorrectly) that
>in the limit R->infinity his rotating example showed an anisotropic
>local speed of light.
>
> To the mystified onlookers: "R&T" refers to Rizzi and
> Tartaglia's preprints gr-qc/9805089 and gr-qc/9904028.
> In essence they show that in the rotating system the sum of
> the rulers laid around the rotating rim does not measure the
> _spatial_ distance around the rim, it measures distance
> along a helix which does not lie in any purely spatial
> 3-space; when one projects this onto a purely spatial
> 3-space, one obtains isotropy for the speed of light in the
> rotating system.
Dennis: Exactly. So the speed of light is isotropic for the rim
observer--despite what he measures. Hmm. And it appears some other sage just
wrote: "One might also describe this in coordinates rotating with the ring
interferometer. In these coordinates the _average_ speed of light
_going_all_the_way_around_the_ring_ is different for the two directions, but
the distance is the same for both rays.
Again there is no mystery -- the light rays travel the same distance at
different average speeds and therefore accumulate a phase difference."
So apparently there is a bit of a problem with this explantion.
Roberts:> This is directly related to my comments elsewhere that this
> system is _ambiguous_
Dennis: Not in ether theory.
Roberts: -- one can select many different but
> individually self-consistent coordinates to describe this.
> I discussed 4 different coordinates in my post, R&T use
> still different coordinates....
Dennis: And you get completely different results for what the speed of light is
wrt the rim observer. Such complications don't occur in ether theory.
D:>> Allegedly, according to the rim observer, the speed of light is still
>>[now corrected:] isotropic--despite what his rulers and clock reads.
>
Roberts:
>First, I suspect you intended to say "isotropic" rather than
>"anisotropic" there. But it really doesn't matter. The thing you are
>missing is the distinction between a local measurement and a non-local
>measurement,
Dennis: Sorry. R&T comes up with a global measurement of
isotropy--contradicting your claim above.
Roberts: and the different procedures used to make them in this
>case.
>
>One can take the sum of the rulers laid around the rotating rim and
>divide it by the time taken for a light pulse to circumnavigate the
>rim (measured on a single clock). This is clearly an _average_
>mesurement. But as R&T showed, this is not really "distance"/"time",
>this is really "distance plus an admixture of time"/"time", and
>calling it "speed" is really a misnomer.
Dennis: LOL. Ahh, so what your stationary rulers read is not necessarily
distance. (Forget your rulers we have this theory you see.) Anyway, let me
again quote a sage who just recently wrote something very different. Notice
his use of the word "speed" for "distance/time" as measured by the rim
observer:
Roberts wrote: "One might also describe this in coordinates rotating with the
ring interferometer. In these coordinates the _average_ speed of light
_going_all_the_way_around_the_ring_ is different for the two directions, but
the distance is the same for both rays.
Again there is no mystery -- the light rays travel the same distance at
different average speeds and therefore accumulate
a phase difference."
That seems pretty clear: "the light rays travel the same distance at different
average speeds." You appeared to be using a "misnomer" there.
Dennis McCarthy
Dennis McCarthy
>counter-rotating light rays or the length of the rim itself is a trivial
>question.
Dennis: By "A trivial question," Bourhis means using stationary rulers to
measure a length of a stationary object. Bourhis feels you can't do that.
By "many people", Bourhis means all engineers, scientists, and physicsts--who
aren't addressing the Sagnac question--*ever* who measure length in the normal
way. In fact, this was the method of measuring length for Sagnac which
**Bourhis himself agreed to** within the last few weeks--before he researched
the subject--because it's somewhat embarrassing to deny it. And in fact, I defy
Bourhis to find any experiment in the history of science where length was
determined in the way he advocates. This new anti--empirical method has been
trotted out simply for the Sagnac effect--and that's it. And its reason is to
save the special theory of relativity. It is a length that can only be
determined based on theoretical assumptions, i.e., by putting pen to paper--and
it is a length that *contradicts* what is actually observed by real
experimenters using real stationary rulers. "Forget what you measure, we have
this theory, you see. So the length around a table is longer counter-clockwise
than clockwise. I know that's not what you measure, but trust us." Geez,
that's not an extra-complicating factor, is it?
B: It is not the case at all. Indeed the naive notion of length
>require your being able to consider the whole rim or the whole rays at a
>given instant. But it can be proved that it is impossible to realize
>coherently such a "space + time splitting" because it is impossible to
>devise an unambiguous global synchronisation procedure on the whole
>ring.
Dennis: That's not only goofy but flat out false. All earth clocks and and all
satellite clocks are absolutely synchronized wrt each other in the GPS. And
the Earth and satellites are rotating. If they weren't synched, planes would
not land as safely as they do.
Bourhis:>However, just to give you a flavour of the issue, let's consider the
>following a priori straightforward situation: two particles are sent
>from some point A on the rim, in opposite directions, with the *same
>speed V with respect to the rim*. According to a clock at A, SR predicts
>that they do not come back at the same time ! This time delay T between
>the two arrivals (which does not depend on V) is observed experimentally
>in neutron experiments as a phase shift [5] between the wave functions
>of these particles (the experimental configuration is not exactly the
>one I described but it is close enough for my example to be relevant).
>
>Now consider two slow moving clocks C+ and C-, respectively co- and
>counter-rotating. If they are synchronized with a clock at point A, when
>they come back to A, C+ and C- are respectively late and ahead with
>respect to A and the difference between their reading is exactly the
>above time delay T.
>
>This shows clearly that there is much more than a speed anisotropy at
>work in Sagnac experiments,
Dennis: How on Earth does it show that? Do you still not understand that the
same effect occurs for sound--and for sound clocks? There's a sound Sagnac
effect--and if you send two sound clocks around the rim--"moving clocks C+ and
C-, respectively co- and
counter-rotating. If they are synchronized with a clock at point A, when
they come back to A, C+ and C- are respectively late and ahead with
respect to A and the difference between their reading is exactly the
above time delay T"???? All with sound. Does that also "show clearly that
there is much more than a speed anisotropy at work in [sound] Sagnac
experiments"?
Tell me Bourhis how do you measure length in the sound Sagnac experiment? Same
way? What's your explanation for sound Sagnac? Or do you use a different one?
Dennis McCarthy
pmb
mention the Sagnc effect
It was Early 1999 in the Am. J. Phys. as I recall
See references therein too
Pete
Tom Roberts <tjro...@lucent.com> wrote in message
news:38C68429...@lucent.com...
Mark Samokhvalov
Luc Bourhis пишет в сообщении <38C63528...@durham.ac.uk> ...
>> path in some mysterious way become, in the course of the ring's rotation,
>> different for the clock-wise and the anti-clockwise waves?
>> 3. If not, how, with the phase velocity being equal for both waves, can a
>> phase difference accumulate?
>
>counter-rotating light rays or the length of the rim itself is a trivial
>require your being able to consider the whole rim or the whole rays at a
>given instant. But it can be proved that it is impossible to realize
>coherently such a "space + time splitting" because it is impossible to
>devise an unambiguous global synchronisation procedure on the whole
>to expose it in ASCII. The interesting reader is refered to [4] and
>references therein.
An excellent example ot high-brow relativistic blabber just to save the,
apparently, initially false constant c assumption. There are no problems in
defining lengths, if it's the same for both rays, if not, there's again no
need to define them - just to cite a PHYSICAL cause which makes two lengths
out of one when the ring rotates wrt stars, and certainly no sync problems.
For an etherist, the cause is simple and one for all RFs - it's constant
speed of light in ether at rest wrt stars. A relativist shrouds the problem
in so many words and formulae, and still fails to come up with an answer.
>
>However, just to give you a flavour of the issue, let's consider the
>following a priori straightforward situation: two particles are sent
>from some point A on the rim, in opposite directions, with the *same
>speed V with respect to the rim*. According to a clock at A, SR predicts
>that they do not come back at the same time !
A clock has nothing to do here - a coincidence indicator does the job. What
d'you mean by "the same speed"? D'you postulate it? If so, it's exactly the
same unanswered question (2).
This time delay T between
>the two arrivals (which does not depend on V) is observed experimentally
>in neutron experiments as a phase shift [5] between the wave functions
>of these particles (the experimental configuration is not exactly the
>one I described but it is close enough for my example to be relevant).
In experiment, postulating equal V's is not enough. You must make them
equal - most probably, it was assumed that opposite equal energy particles
have equal V's wrt to the rotating ring - a wrong assumption from the
etherist viewpoint because m(V) is wrt ether.
>
>Now consider two slow moving clocks C+ and C-, respectively co- and
>counter-rotating. If they are synchronized with a clock at point A, when
>they come back to A, C+ and C- are respectively late and ahead with
>respect to A and the difference between their reading is exactly the
>above time delay T.
This, again is not surprising, since time dilation in clocks moving wrt
ether is an experimental fact attributable to ether wind action on the
frequency standard. The ether approach would, in addition, expect a
dependence on the clock type - a clock with a directional frequency standard
(e.g., a piezoquartz resonator) could change its ticking rate with a change
in orientation. By the way, there's sufficient experimental evidence on the
ticking rate of satellite clocks to belie the equivalence pinciple - it's
different on different satellites, whereas conditions inside them should be
indistinguishable.
>
>This shows clearly that there is much more than a speed anisotropy at
>work in Sagnac experiments, even if an etherist might believe at first
>that it is a possible explanation for Sagnac experiments based on light
propagation.
By no means. For an etherist, there's nothing more than speed anisotropy in
Sagnac's experiment, but in other experiments, there are other ether wind
effects
[1] J. Anandan, Phys. Rev. D, Vol. 24, N. 2, (1981) 338
>[2] G. Rizzi, A. Tartaglia, gr-qc/9805089
>[3] E.J. Post, Rev. Mod. Phys., Vol. 39, N. 2 (1967) 475
>[4] V. Cantoni, Il Nuovo Cimento, Vol. 57 B, N. 1 (1968) 220
>[5] S.A. Werner et al, Phys. Rev. A 21 (1980) 1419
Luc Bourhis
(in message <20000308124906...@ng-fm1.aol.com>):
>> This shows clearly that there is much more than a speed anisotropy at
>> work in Sagnac experiments,
>
> Dennis: How on Earth does it show that? Do you still not understand that the
> same effect occurs for sound--and for sound clocks?
What I have explained is treated extensively and precisely in the references
I have given. So it is now your turn: please show your math or at least some
references to them and please do not forget to explain the effects for the
two particles moving with the same speed wrt the rim: no speed anisotropy by
definition there.
--
Luc Bourhis
Center of Particle Physics/University of Durham
Luc Bourhis
(in message <8a68pl$utl$1...@gavrilo.mtu.ru>):
>> As many people, you consider that defining the length of co- and
>> counter-rotating light rays or the length of the rim itself is a trivial
>> question. It is not the case at all. Indeed the naive notion of length
>> require your being able to consider the whole rim or the whole rays at a
>> given instant. But it can be proved that it is impossible to realize
>> coherently such a "space + time splitting" because it is impossible to
>> devise an unambiguous global synchronisation procedure on the whole
>> ring. I will not give this demonstration because it is too complicated
>> to expose it in ASCII. The interesting reader is refered to [4] and
>> references therein.
>
> An excellent example ot high-brow relativistic blabber just to save the,
> apparently, initially false constant c assumption. There are no problems in
> defining lengths, if it's the same for both rays, if not, there's again no
> need to define them - just to cite a PHYSICAL cause which makes two lengths
> out of one when the ring rotates wrt stars, and certainly no sync problems.
> For an etherist, the cause is simple and one for all RFs - it's constant
> speed of light in ether at rest wrt stars. A relativist shrouds the problem
> in so many words and formulae, and still fails to come up with an answer.
Before defining you as an etherist, you have to precise clearly what ether
theory you want to use to model a Sagnac experiment. Be careful because in
order to escape the difficulties encountered with SR, you have to avoid
LET-like theories which have Lorentz transforms embedded in them. But then
you are most surely in trouble with Michelson & Morley, Kennedy & Thorndike
or Doppler because an Ether theory compatible with these experiments is
equivalent to SR as long as we are concerned with observable predictions. So
I would say that this is the typical answer of an etherist on this forum:
taught about what is the situation in pedagogical terms and referred to
serious references to obtain a deeper knowledge, he comes with a ghost
rebutal not supported by any scientific argument. I am disappointed to see
that you have not better prepared your troll.
>> However, just to give you a flavour of the issue, let's consider the
>> following a priori straightforward situation: two particles are sent
>> from some point A on the rim, in opposite directions, with the *same
>> speed V with respect to the rim*. According to a clock at A, SR predicts
>> that they do not come back at the same time !
>
> A clock has nothing to do here
It could have if one was measuring the arrival times ....
> - a coincidence indicator does the job.
... but indeed one performs quantum experiment and observe the interferences
between the particles going in opposite directions. However the phase shift
is directly proportional to the time delay.
> What d'you mean by "the same speed"? D'you postulate it?
The same speed. I can not be clearer. It is imposed by the experimental
configuration. See below.
> If so, it's exactly the same unanswered question (2).
The 3 following objects have different length:
- the trajectory of a co-rotating particle
- the trajectory of a counter-rotating particle
- the rim
if one works in the non-inertial frame whose world lines are defined by the
following parametric equations in some inertial frame:
x0 = t
x1 = a cos(w t) - b sin(w t)
x2 = a sin(w t) + b cos(w t)
x3 = 0,
with (a^2+b^2)^(1/2) being the radius of the rim and w its rotation speed.
>> This time delay T between
>> the two arrivals (which does not depend on V) is observed experimentally
>> in neutron experiments as a phase shift [5] between the wave functions
>> of these particles (the experimental configuration is not exactly the
>> one I described but it is close enough for my example to be relevant).
>
> In experiment, postulating equal V's is not enough. You must make them
> equal - most probably, it was assumed that opposite equal energy particles
> have equal V's wrt to the rotating ring - a wrong assumption from the
> etherist viewpoint because m(V) is wrt ether.
Again which Ether theory ? Anyway for the non-relativistic particles used
here, de Broglie law relating the wave-length lambda, and therefore the
energy of the particles, their mass m and their speed v,
lambda = h/(m v)
is exceptionaly well verified. Then the two beams are obtained from one
incoming beam by a Bragg diffraction through a layer of silicon. The optical
nature of the phenomena guaranties that the wave-length of the two outgoing
beams is the same. Therefore the situation is the one I have described and
you have only forced me to explain the details related to my remark between
parentheses. Note that the same kind of experiments have been made with
electrons [7] (thanks to Tom Roberts for the reference).
So now how can you explain the experimental results ?
>> Now consider two slow moving clocks C+ and C-, respectively co- and
>> counter-rotating. If they are synchronized with a clock at point A, when
>> they come back to A, C+ and C- are respectively late and ahead with
>> respect to A and the difference between their reading is exactly the
>> above time delay T.
>
> This, again is not surprising, since time dilation in clocks moving wrt
> ether is an experimental fact attributable to ether wind action on the
> frequency standard.
What is tremendously interesting however is that one finds the same T for
this shift between clocks and for the delay between the arrival time of
particles rotating in opposite direction even if a priori there is no links
between these two configurations. If one remembers that the same geometry of
spacetime is at work, everything becomes clear and indeed the important point
is of course that SR gives the correct predictions for all these effects. And
Ether theories ?
> The ether approach would, in addition, expect a
> dependence on the clock type - a clock with a directional frequency standard
> (e.g., a piezoquartz resonator) could change its ticking rate with a change
> in orientation. By the way, there's sufficient experimental evidence on the
> ticking rate of satellite clocks to belie the equivalence pinciple - it's
> different on different satellites, whereas conditions inside them should be
> indistinguishable.
I do not understand : do you say the the equivalence principle can be
believed or that it is ruled out ? I do not know any experimental data
supporting the latter.
[4] V. Cantoni, Il Nuovo Cimento, Vol. 57 B, N. 1 (1968) 220
[5] S.A. Werner et al, Phys. Rev. A 21 (1980) 1419
[6] C.M. Will, gr-qc/9811036
[7] Allan et al, Science, 228 (1985), p69.
Dennis McCarthy
>On Wed, 8 Mar 2000 17:49:06 +0000, Dennis McCarthy wrote
>(in message <20000308124906...@ng-fm1.aol.com>):
>
>>> This shows clearly that there is much more than a speed anisotropy at
>>> work in Sagnac experiments,
>>
>> Dennis: How on Earth does it show that? Do you still not understand that
>the
>> same effect occurs for sound--and for sound clocks?
>
references
>I have given. > So it is now your turn: please show your math or at least some
>references to them
Dennis: You have given no evidence for your claim above. That's just a strange
Bourhis conclusion.
Moreover, when you first came to this thread I had to show you the precise
mathematical description of sound Sagnac, ether Sagnac and sound clocks. It's
an obvious physical fact that no one denies--and takes three lines of algebra.
Also, it took me two weeks of getting past all of your ridiculous
objections--but you finally understood it (sound and ether Sagnac.) I'm not
going through it again. If you don't believe sound Sagnac occurs or just want
to deny obvious physical facts that you find inconvenient and irritating, then
this discussion is not worth my time and you are not on an objective search for
the truth.
Also, you gave references for the interesting argument that the length of a
rim is not the same CW as CCW for a rim observer. Very strange to say the
least.
You haven't replied to the following:
Bourhis:
>As many people, you consider that defining the length of co- and
>counter-rotating light rays or the length of the rim itself is a trivial
>question.
Dennis: By "A trivial question," Bourhis means using stationary rulers to
measure a length of a stationary object. Bourhis feels you can't do that.
By "many people", Bourhis means all engineers, scientists, and physicsts--who
aren't addressing the Sagnac question--*ever* who measure length in the normal
way. In fact, this was the method of measuring length for Sagnac which
**Bourhis himself agreed to** within the last few weeks--before he researched
the subject--because it's somewhat embarrassing to deny it. And in fact, I defy
Bourhis to find any experiment in the history of science where length was
determined in the way he advocates. This new anti--empirical method has been
trotted out simply for the Sagnac effect--and that's it. And its reason is to
save the special theory of relativity. It is a length that can only be
determined based on theoretical assumptions, i.e., by putting pen to paper--and
it is a length that *contradicts* what is actually observed by real
experimenters using real stationary rulers. "Forget what you measure, we have
this theory, you see. So the length around a table is longer counter-clockwise
than clockwise. I know that's not what you measure, but trust us." Geez,
that's not an extra-complicating factor, is it?
Dennis McCarthy
Dennis McCarthy
>On Wed, 8 Mar 2000 19:15:16 +0000, Mark Samokhvalov wrote
>(in message <8a68pl$utl$1...@gavrilo.mtu.ru>):
>
>>> As many people, you consider that defining the length of co- and
>>> counter-rotating light rays or the length of the rim itself is a trivial
>>> question. It is not the case at all. Indeed the naive notion of length
>>> require your being able to consider the whole rim or the whole rays at a
>>> given instant. But it can be proved that it is impossible to realize
>>> coherently such a "space + time splitting" because it is impossible to
>>> devise an unambiguous global synchronisation procedure on the whole
>>> ring. I will not give this demonstration because it is too complicated
>>> to expose it in ASCII. The interesting reader is refered to [4] and
>>> references therein.
>>
>> An excellent example ot high-brow relativistic blabber just to save the,
>> apparently, initially false constant c assumption. There are no problems in
>> defining lengths, if it's the same for both rays, if not, there's again no
>> need to define them - just to cite a PHYSICAL cause which makes two lengths
>> out of one when the ring rotates wrt stars, and certainly no sync problems.
>> For an etherist, the cause is simple and one for all RFs - it's constant
>> speed of light in ether at rest wrt stars. A relativist shrouds the problem
>> in so many words and formulae, and still fails to come up with an answer.
>
>order to escape the difficulties encountered with SR, you have to avoid
>LET-like theories which have Lorentz transforms embedded in them.
Dennis: You are coming close to outright dishonesty. The only person in the
world who follows the type of LET that you use to confuse situations and
complicate Sagnac is you. All other known etherists (Michelson, Sagnac, Ives,
etc., and those on these boards and all whom I know personally), no matter what
the ether theory, derive the Sagnac effect quite simply with the Galilean
analysis.
Now, unfortunately, the following involves physical reasoning, but I'll still
try. In the Sagnac effect, the Lorentz contraction can be disregarded by
Lorentzians because there is only one rim and so LC has an equal effect on both
path lengths. Also, no clock movements or synch procedures need to be made.
Thus, the Galilean nature of light is clearly recovered in the
experiment--because there are no relevant deformations of the measuring devices
to counteract this Galilean nature. And **all** etherists whom I know believe
in the underlying Galilean nature of light. Lorentzians apply the Lorentzian
corrections only when measuring devices are altered in a relevant way. If not,
then the Galilean nature is recovered, and as you know, I hope, it takes 3
lines of algebra to produce Sagnac.
B: But then
>you are most surely in trouble with Michelson & Morley, Kennedy & Thorndike
>or Doppler because an Ether theory compatible with these experiments is
>equivalent to SR as long as we are concerned with observable predictions.
Dennis: That's false. Obviously. IGS theory, for example, fits the known
experiments. And Lorentz contraction does not need to be assumed.
B:So
>I would say that this is the typical answer of an etherist on this forum:
>taught about what is the situation in pedagogical terms and referred to
>serious references to obtain a deeper knowledge, he comes with a ghost
>rebutal not supported by any scientific argument.
Dennis: The etherist argument was put forth by Sagnac in 1913 in the original
paper on the subject. The Galilean analysis that predicts the result came
centuries before that. It is unfortunate that you still pretend to be unaware
of it.
Dennis McCarthy
Standeven
Mark Samokhvalov wrote:
> Luc Bourhis пишет в сообщении <38C63528...@durham.ac.uk> ...
> >
> >However, just to give you a flavour of the issue, let's consider the
> >following a priori straightforward situation: two particles are sent
> >from some point A on the rim, in opposite directions, with the *same
> >speed V with respect to the rim*. According to a clock at A, SR predicts
> >that they do not come back at the same time !
>
> A clock has nothing to do here - a coincidence indicator does the job. What
> d'you mean by "the same speed"? D'you postulate it? If so, it's exactly the
> same unanswered question (2).
No, our observers measure it. They, for some strange reason, are under the
impression that the speeds they measure with their clocks and rulers are
the actual speeds in their frame.
I suppose _you're_ going to say that their measurements are invalid for
some reason now, aren't you...
Robert Chan
>That paragraph I quoted does not confine its "attention to
>inertial coordinates." Instead, it states "but of course such
>coordinates are necessarily accelerating (viz., rotating), and
>special relativity does not assume light speed to be isotropic
>with respect to non-inertial coordinates."
That web page mentions analyzing the Sagnac device in terms of
coordinates rigidly fixed to the ring, notes that these are
necessarily accelerating coordinates, notes that lightspeed need
not be c with respect to such coordinates, comments on how one
might imagine that this leads to a contradiction, since it IS
possible to define a coordinate system "in terms of which the
position of a point fixed on the disk is independent of time", and
then defers further discussion of accelerated coordinates until
later, saying "For the moment, let's just confine our attention
to inertial coordinates...", following which appears an analysis
of the Sagnac device in terms of the co-moving inertial coordinates
of a fixed point on the ring. In the subsequent sections it
describes the helical locus of local simultaneity implied by the
the sequence of co-moving inertial coordinates, and then gives an
account in terms of a single accelerating coordinate system and
the resulting pseudo-gravitational potentials. In summary, you
misread, misunderstood, and misrepresented the reference (IMHO).
On 08 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>Are you arguing that it is theoretically acceptable for the
>SR explanation to assume that the speed of light is non-
>isotropic for the rim observer?
Fundamentally the Sagnac effect from an SR perspective is due
to the difference in optical path lengths, but it's possible to
define spatial and temporal parameters in terms of which this
optical path lengh difference can be expressed as an equivalent
anisotropy in the "speed of light" at various points around
the rim. Of course, this involves defining "speed" in terms
of distances and times that are not components of a single
inertial coordinate system. The reference web page describes
in detail one way of doing this.
You have to be careful not to confuse the different approaches
that can be taken to describe the operation of a Sagnac device.
First, since the Sagnac effect is not essentially relativistic,
it's possible to get the right answer by taking a Galilean approach.
Second, there is the drop-dead simple SR method in terms of a single
system of inertial coordinates, which is how anyone in their right
mind approaches the problem. Needless to say, the speed of light
is isotropic with respect to this parameterization.
Now, if we get bored doing things the sensible way, there are (at
least) two ways that we can describe "how this looks" in terms of
coordinates in which an observer fixed on the rim is stationary.
The first way is to use momentarily co-moving inertial coordinates,
which vary as the disk rotates. This is still an "SR explanation"
in the sense that no pseudo-gravitational potentials are invoked,
but it's really a composite view over a sequence of coordinate
systems, each of which is inertial in itself, but the union of
which does not constitute a single inertial frame. Instead it
yields a helical locus of simultaneity, and of course a difference
in the effective path lengths in the two directions around the
rim. In this case, as mentioned above, it's possible to define
space and time parameters in such a way that we can express the
difference in path lengths as an equivalent difference in light
"speed", on the understanding that this speed is not defined in
terms of components of an inertial coordinate system. (There's
not much reason to actually DO this, other than to show that
it's possible.)
Another approach is to use a single accelerating coordinate
system, with respect to which a given point on the rim is
*permanently* stationary. This requires the introduction of
pseudo-gravitational potentials to account for the accelerations
to which the various points on the rim are subjected with respect
to these accelerated coordinates. Some people would call this
a "GR" approach, but since the spacetime is still flat, this is
debatable. In any case, the key here is to properly account
for ALL the accelerations, including the Coriolis acceleration,
which turns out to be the dominant factor in establishing the
pseudo-gravitational potential corresponding to the differential
progress of light around the rim in the two directions, because
the Coriolis effect is different for the two directions.
This is all standard stuff, and has been explained many times
before. For example, there's a nice overview in Ciufolini and
Wheeler's "Gravitation and Inertia".
On 08 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>...the only "mistake" of Selleri that was *alleged* by R&T was
>that the paradox negates the SR view.
Selleri claimed (in a self-published note) that Sagnac was
inconsistent with special relativity. Rizzi and Tartaglia
published a rebutal, pointing out that Selleri was mistaken (as
if this wasn't obvious), and they highlighted one particular
flaw in Selleri's reasoning, sufficient to invalidate his claim.
However, R&T did not detect (or at least didn't mention) ALL of
the errors in Selleri's reasoning. (This would have made for a
MUCH longer paper.) They focused only on the most interesting
error in his reasoning, one that has been committed by other
people as well, namely, the assumption that we can always define
a single-valued foliation of simultaneity for an accelerating
observer. Of course, this assumption is false, and has always
been known to be false, i.e., this was not a discovery of R&T.
They simply published their note to rebut Selleri and as an
informational service to highlight an interesting aspect of
special relativity.
One of Selleri's errors that R&T failed to mention in their
little rebutal note was his simple failure to correctly evaluate
the "anisotropic speed ratio" in the limit of increasing radius,
even according to his own (flawed) premises. He asserted that
this ratio remains constant as the radius increases to infinity,
leading to (he claimed) a conflict with special relativity in
the limit of *linear* light paths. The correct analysis shows
that the deviation from 1 of the "anisotropic ratio" is always
exactly proportional to the *angular* travel of the device
during the transit of light, and this remains true in the
limit as the radius increases to infinity.
On 08 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>RChan: Again, just so no one is misled, Dennis is completely
>incorrect in his assessment. There is nothing mysterious about
>accelerating coordinate systems, at least not to anyone who
>understands them.
>
>Dennis: Are you trying to argue that R&T's position regarding
>the Sagnac effect was *not* that the "path becomes, in the
>course of the ring's rotation, different for the clock-wise
>and the anti-clockwise waves"--even for the rim observer?
Why on Earth would I be trying to argue that? Let's see now,
you're saying that R&T are saying that the path lengths are
different due to the absolute rotation of the ring. Gosh,
what an insight. How mysterious! Actually, that's what I
(and everyone else, as far as I can tell) have been saying
all along, including the reference web page, which says "Notice
that this anisotropy ... for any inertial frame is actually
in the distance travelled, not the speed of travel", and then
goes on to describe the helical locus of simultaneity, etc.
What I WAS arguing is that "There is nothing mysterious about
Mark Samokhvalov
Luc Bourhis пишет в сообщении
To my knowledge, ALL experiments performed to detect the effect of the
Earth's orbital velocity on physical processes, including my own to detect
the anisotropy of electrophysical parameters induced by it, have produced
nil results. Together with the existence of star aberration, this could be
explained by ether drag by the Earth's gravitational field and verified by
any of the aforementioned experiments on board satellites, or on the Earth
by such experiments sensitive enough to detect the effects of Earth's
rotation velocity. Perhaps, such experiments have already been performed -
any information?
Clearly, a case when sollipsism comes in conflict with reality - different
results obtained by reasoning with no physical cause. SR was originally
constructed not as a physical, but as a metric theory - had another signal
carrier (e.g., fast particles) been used, the results would have been
different. Had different signal carriers been used jointly, all ambiguity
(=relativity), would have been removed.
Indeed, during the XX-th century triumphs of theoretical physics elated the
intellectual elite aleready influenced by sollipsist philosophy to the
extent that they thought they could construct reality. It the same with
quantum physics: all sorts of weird hypotheses have been advanced to explain
the interference of isolated quanta instead of aknowledging the simple fact
of their division and propagation in the form of sub-quantum oscillations.
>>> This time delay T between
>>> the two arrivals (which does not depend on V) is observed experimentally
>>> in neutron experiments as a phase shift [5] between the wave functions
>>> of these particles (the experimental configuration is not exactly the
>>> one I described but it is close enough for my example to be relevant).
>>
>> In experiment, postulating equal V's is not enough. You must make them
>> equal - most probably, it was assumed that opposite equal energy
particles
>> have equal V's wrt to the rotating ring - a wrong assumption from the
>> etherist viewpoint because m(V) is wrt ether.
>
>Again which Ether theory ? Anyway for the non-relativistic particles used
>here, de Broglie law relating the wave-length lambda, and therefore the
>energy of the particles, their mass m and their speed v,
> lambda = h/(m v) is exceptionaly well verified. Then the two beams are
obtained from one
>incoming beam by a Bragg diffraction through a layer of silicon. The
optical
>nature of the phenomena guaranties that the wave-length of the two outgoing
>beams is the same. Therefore the situation is the one I have described and
>you have only forced me to explain the details related to my remark between
>parentheses. Note that the same kind of experiments have been made with
>electrons [7] (thanks to Tom Roberts for the reference).
>
>So now how can you explain the experimental results ?
>The experimental fact of inertial mass vs V dependence explained/predicted
by several theories, includung SR. With the ether concept, V is measured wrt
ether, and therefore in the ring's RF it will be different for co- and
counter-rotating equal energy particles.
>>> Now consider two slow moving clocks C+ and C-, respectively co- and
>>> counter-rotating. If they are synchronized with a clock at point A, when
>>> they come back to A, C+ and C- are respectively late and ahead with
>>> respect to A and the difference between their reading is exactly the
>>> above time delay T.
>>
>> This, again is not surprising, since time dilation in clocks moving wrt
>> ether is an experimental fact attributable to ether wind action on the
>> frequency standard.
>
>What is tremendously interesting however is that one finds the same T for
>this shift between clocks and for the delay between the arrival time of
>particles rotating in opposite direction even if a priori there is no links
>between these two configurations. If one remembers that the same geometry
of
>spacetime is at work, everything becomes clear and indeed the important
point
>is of course that SR gives the correct predictions for all these effects.
And
>Ether theories ?
No space-time needed. Suffice it that both effects are described by small
terms quadratic in V. Integration over travel time produces the result.
>
>> The ether approach would, in addition, expect a
>> dependence on the clock type - a clock with a directional frequency
standard
>> (e.g., a piezoquartz resonator) could change its ticking rate with a
change
>> in orientation. By the way, there's sufficient experimental evidence on
the
>> ticking rate of satellite clocks to belie the equivalence pinciple - it's
>> different on different satellites, whereas conditions inside them should
be
>> indistinguishable.
>
>I do not understand : do you say the the equivalence principle can be
>believed or that it is ruled out ? I do not know any experimental data
>supporting the latter.
>
I mean, it doesn't work, because the clocks on satellites at different
altitudes tick differently.
Luc Bourhis
>
> >
> >On Wed, 8 Mar 2000 17:49:06 +0000, Dennis McCarthy wrote
> >(in message <20000308124906...@ng-fm1.aol.com>):
> >
> >>> This shows clearly that there is much more than a speed anisotropy at
> >>> work in Sagnac experiments,
> >>
> >> Dennis: How on Earth does it show that? Do you still not understand that the
> >> same effect occurs for sound--and for sound clocks?
> >
> >I have given. So it is now your turn: please show your math or at least some
> >references to them
>
> Dennis: You have given no evidence for your claim above. That's just a strange
> Bourhis conclusion.
For the moment I have not seen either Tom Roberts or Steve Carlip
contradicting me. Usually they do not hesitate to point out errors in
whatever messages they are made. Do you think you know better Special
and General Relativity than all of us ?
> Moreover, when you first came to this thread I had to show you the precise
> mathematical description of sound Sagnac, ether Sagnac and sound clocks. It's
> an obvious physical fact that no one denies--and takes three lines of algebra.
For Sagnac experiment, you have shown only a mere Galilean analysis
which does give the correct result for light only because terms in
(v/c)^2 are experimentally not observable. However this same kind of
analysis predicts no delay between the comeback of two particles sent
simultaneously in opposite direction with the same speed with respect to
the rim. SR predicts on the contrary a delay and this effects is
observed for neutron and electrons [1,2]. So how do you reconciliate
your point of view with experimental results ? Surely not with clocks.
Moreover your sound clocks are the analogs of Einstein light clocks :
waves bouncing between two walls. How do you manage to model mechanical
clocks, atomic clocks, molecular clocks, instable particles decaying
through weak interaction, instable particles decaying through strong
interaction with such a kindergarten *non-quantum* model ? Is it that
you have to postulate that this simple analogy can be extended to treat
any kind of periodical phenomena ? But are you not using the Postulate
of Relativity then ? If fact you have advocated a long time ago what you
called PLET (Poincarre LET), i.e. LET + PoR. Well it was before your
infatuation for IGS.
> Also, you gave references for the interesting argument that the length of a
> rim is not the same CW as CCW for a rim observer. Very strange to say the
> least.
Strange is not by itself a scientific comment. Furthermore you are
mistaken. Co- and counter-rotating light rays do not have the same
lengths and these lengths are different from the one of the rim.
Precisely (I have to be careful: Tom and Steve are around in this
thread) this is true in the non-inertial frame whose world lines are
paramametrized by:
x0 = t
x1 = R cos(w t)
x2 = R sin(w t)
x3 = 0
where R is the radius of the rim and w its angular speed (as you see
this frame is intuitively the rim). This comes from the fact that
neither the rim nor the light rays are well defined geometrical objects
entirely embedded in space at a given instant.
This is a definitive result of SR and/or GR, and of course of LET -- the
theory exposed by Lorentz in 1904 can indeed be extended to deal with
non-inertial frame as SR is and this results in the same framework since
SR and LET are equivalent for inertial motions.
> You haven't replied to the following:
Sun-Tzu said : "When involved in a guerilla, launch first the attacks
which do not cost you anything".
> >As many people, you consider that defining the length of co- and
> >counter-rotating light rays or the length of the rim itself is a trivial
> >question.
>
> Dennis: By "A trivial question," Bourhis means using stationary rulers to
> measure a length of a stationary object. Bourhis feels you can't do that.
> By "many people", Bourhis means all engineers, scientists, and physicsts--who
> aren't addressing the Sagnac question--*ever* who measure length in the normal
> way.
That is to say in situations where relativistic effects are completely
negligeable. That is to say by working with a Galilean framework which
was indeed a good approximation.
> In fact, this was the method of measuring length for Sagnac which
> **Bourhis himself agreed to** within the last few weeks--before he researched
> the subject--because it's somewhat embarrassing to deny it. And in fact, I defy
> Bourhis to find any experiment in the history of science where length was
> determined in the way he advocates.
The definition of length used in [4] and precisely explained in [3] is
used routinely in GR for a very long time. Moller [5] described it in a
book published in the 60's and it is therefore even older. It is a very
general definition because it is equivalent locally to the kind of
intuitive method you advocate which uses rulers -- semi-precisely, it
transforms the measurement of the length of a 1-dimensional body in a
frame R into an infinite succession of length measurements at successive
points P by inertial observers moving with the same speed as R at this
point P. So this means naively that for infinitesimal lengths we are
back to our usual rulers.
Difficulties do only occur when one considers global properties, the
whole rim for example. These difficulties are seen only for a particular
class of non-inertial frames (see [5] p. 248 for a complete analysis)
and rotating frames are in this class. And yes this is a new effect
predicted by Special Relativity and LET but not by Galilean Relativity.
But how is it possible to be surprised by this fact ?
> This new anti--empirical method has been
> trotted out simply for the Sagnac effect--and that's it. And its reason is to
> save the special theory of relativity.
It is blatantly wrong as explained above. Before criticizing modern
physic one is supposed to learn it. You know you can not get this
knowledge solely from this newsgroup. Contributors like me do not have
the time or the energy to give the best pedagogical explanations and we
have to be often too concise or sketchy.
> It is a length that can only be
> determined based on theoretical assumptions, i.e., by putting pen to paper--and
> it is a length that *contradicts* what is actually observed by real
> experimenters using real stationary rulers.
You are again completely confused. An observer moving infinitely slowly
along the rim will measure the perimeter:
L = 2 pi R/(1-(R Omega)^2)^(1/2)
in units where c=1. But this is not the length of a light ray
propagating along the rim in the non-inertial frame I have defined
precisely above. Now how do you propose to measure with rulers the
length of a light ray ?
[1] S.A. Werner et al, Phys. Rev. A 21 (1980) 1419
[2] Hasselbach and Nicklaus, Phys. Rev. A 48#1 (1993), p143.
[3] J. Anandan, Phys. Rev. D, Vol. 24, N. 2, (1981) 338
[4] G. Rizzi, A. Tartaglia, gr-qc/9805089
[5] C. Moller, The Theory of Relativity (Oxford 1952)
Dennis McCarthy
>>Dennis: Are you trying to argue that R&T's position regarding
>>the Sagnac effect was *not* that the "path becomes, in the
>>course of the ring's rotation, different for the clock-wise
>>and the anti-clockwise waves"--even for the rim observer?
>
>you're saying that R&T are saying that the path lengths are
>different due to the absolute rotation of the ring. Gosh,
>what an insight. How mysterious! Actually, that's what I
>(and everyone else, as far as I can tell) have been saying
>all along, including the reference web page, which says "Notice
>that this anisotropy ... for any inertial frame is actually
>in the distance travelled, not the speed of travel",
Dennis: Perhaps, you should read the paper again? R&T are arguing the distance
is different according to the frame **for the rim observer**--for the frame of
the rim. That means the desk your computer is on would be longer CCW than
CW--according to *you*--who is stationary wrt the desk despite what you
measure.
And apparently that result is "mysterious" --as you didn't understand it.
I have snipped your other mistakes as they all relate to that point.
Dennis McCarthy
Luc Bourhis
>
> >
> >On Wed, 8 Mar 2000 19:15:16 +0000, Mark Samokhvalov wrote
> >(in message <8a68pl$utl$1...@gavrilo.mtu.ru>):
> >
> >theory you want to use to model a Sagnac experiment. Be careful because in
> >order to escape the difficulties encountered with SR, you have to avoid
> >LET-like theories which have Lorentz transforms embedded in them.
>
> world who follows the type of LET that you use to confuse situations and
> complicate Sagnac is you. All other known etherists (Michelson, Sagnac, Ives,
> etc., and those on these boards and all whom I know personally), no matter what
> the ether theory, derive the Sagnac effect quite simply with the Galilean
> analysis.
And you are then using incoherent ad hoc solution ruled out
experimentaly if you advocate a mere Galilean analysis of the Sagnac
effect. Indeed,
1) Are you really ready to promote LET for Michelson & Morley, Kennedy &
Thorndike, Trouton & Noble, ..... while you advocate a Galilean analysis
as the fundamental theory for Sagnac ?
2) Or is it that a Galilean analysis is a good approximation of LET when
it comes to compare the theoretical predictions with the experimental
results of light Sagnac experiments ?
3) But then what about the experiments made with massive particles for
which this Galilean analysis is completely wrong ? How do you treat this
case ?
> Now, unfortunately, the following involves physical reasoning, but I'll still
> try. In the Sagnac effect, the Lorentz contraction can be disregarded by
> Lorentzians because there is only one rim and so LC has an equal effect on both
> path lengths. Also, no clock movements or synch procedures need to be made.
> Thus, the Galilean nature of light is clearly recovered in the
> experiment--because there are no relevant deformations of the measuring devices
> to counteract this Galilean nature. And **all** etherists whom I know believe
> in the underlying Galilean nature of light.
Obviously not Lorentz.
> Lorentzians apply the Lorentzian
> corrections only when measuring devices are altered in a relevant way. If not,
> then the Galilean nature is recovered, and as you know, I hope, it takes 3
> lines of algebra to produce Sagnac.
But you end up with a theory which has to treat differently light
propagation, motion of clocks and motion of massive particles around the
rim. On the contrary SR treats all these effects exactly in the same way
and the results can also be derived in a few lines of algebra if one
works in an inertial frame in which the rim is rotating. And more
importantly, this SR treats also with the same tools every experiments
involving inertial frames, and in many cases (all MMX-line experiments),
the result is a mere tautology.
> >But then
> >you are most surely in trouble with Michelson & Morley, Kennedy & Thorndike
> >or Doppler because an Ether theory compatible with these experiments is
> >equivalent to SR as long as we are concerned with observable predictions.
>
> Dennis: That's false. Obviously. IGS theory, for example, fits the known
> experiments. And Lorentz contraction does not need to be assumed.
IGS postulate that the Earth is corotating with a vortex of Ether and
therefore that the speed of a lab on Earth wrt Ether is tiny. But then
you have to assume the consequences of this hypothesis: a vortex around
the Earth corotating with the Moon, a vortex around Saturn corotating
with its satellites. But wait the trajectory of these satellites are not
in the same planes and their periods of rotation are very different. So
does this leads to some observable effects related to the propagation of
the light coming from these objects ? Or do you need one vortex for each
satellite ? Same problem with Jupiter. And what about comets ?
And more importantly where is the complete exhaustive quantitative
comparison of the prediction of IGS with the available relevant
experimental data ? GR and SR predictions and their confrontation to
experiments are reported in hundreds of papers published in widely
available journals. There are even summaries of the current situation,
cf [1] for example. So if you want to convince mainstream science you
have to produce a work with the same quality. Can you do that ?
[1] C.M. Will, gr-qc/9811036 and references therein
Dennis McCarthy
>
>Dennis McCarthy wrote:
>>
>> >
>> >On Wed, 8 Mar 2000 17:49:06 +0000, Dennis McCarthy wrote
>> >(in message <20000308124906...@ng-fm1.aol.com>):
>> >
>> >>> This shows clearly that there is much more than a speed anisotropy at
>> >>> work in Sagnac experiments,
>> >>
>> >> Dennis: How on Earth does it show that? Do you still not understand
>that the
>> >> same effect occurs for sound--and for sound clocks?
>> >
>> >What I have explained is treated extensively and precisely in the
>references
>> >I have given. So it is now your turn: please show your math or at least
>some
>> >references to them
>>
>> Dennis: You have given no evidence for your claim above. That's just a
>strange
>> Bourhis conclusion.
>
>contradicting me. Usually they do not hesitate to point out errors in
>whatever messages they are made. Do you think you know better Special
>and General Relativity than all of us ?
Dennis: Forgive me for not being convinced by
proof-by-non-contradiction-by-authority, when my point seems so clear. I'll
repeat it:
Bourhis wrote: ">Now consider two slow moving clocks C+ and C-, respectively
co- and
>counter-rotating. If they are synchronized with a clock at point A, when
>they come back to A, C+ and C- are respectively late and ahead with
>respect to A and the difference between their reading is exactly the
>above time delay T.
>
>This shows clearly that there is much more than a speed anisotropy at
>work in Sagnac experiments, "
Obviously, your argument involving changing clocks cannot rule out the
possibility that speed anisotropy can the cause of the Sagnac effect. This is
true because open-air sound clocks moving around a rotating rim experience the
same effect as described in your premise--and speed anisotropy is what causes
the sound Sagnac.
A cannot entail B when I show an instance where A is true and B is false.
D:>> Also, you gave references for the interesting argument that the length
of
>a
>> rim is not the same CW as CCW for a rim observer. Very strange to say the
>> least.
>
B: >Strange is not by itself a scientific comment.
Dennis: Well, it certainly contradicts what the rim observer measures--as well
as the procedure for determining lengths in all known experiments, including
the one you agreed to.
Bourhis: . This comes from the fact that
>neither the rim nor the light rays are well defined geometrical objects
>entirely embedded in space at a given instant.
Dennis: Ether theories don't have this problem with hypothesizing an
*unobservable* problem with geometrical objects entirely embedded in space at a
given instant.
Bourhis: >This is a definitive result of SR and/or GR, and of course of LET
Dennis: Please stop confusing your idiosyncratic views of a 1904 paper with
ether theories followed today. I have asked you many times to stop this.
B:>Sun-Tzu said : "When involved in a guerilla, launch first the attacks
>which do not cost you anything".
Dennis: I think we should be on an objective search for the truth, not a
guerilla attack.
B:>> >As many people, you consider that defining the length of co- and
>> >counter-rotating light rays or the length of the rim itself is a trivial
>> >question.
>>
>> Dennis: By "A trivial question," Bourhis means using stationary rulers to
>> measure a length of a stationary object. Bourhis feels you can't do that.
>> By "many people", Bourhis means all engineers, scientists, and
>physicsts--who
>> aren't addressing the Sagnac question--*ever* who measure length in the
>normal
>> way.
>
Bourhis: >That is to say in situations where relativistic effects are
completely
>negligeable. That is to say by working with a Galilean framework which
>was indeed a good approximation.
Dennis: Trusting your stationary rulers to measure length of stationary objects
is a "Galilean framework"? And ignoring what you actually measured and going
by theory instead is the relativistic method. Okay, agreed.
D:>> In fact, this was the method of measuring length for Sagnac which
>> **Bourhis himself agreed to** within the last few weeks--before he
>researched
>> the subject--because it's somewhat embarrassing to deny it. And in fact, I
>defy
>> Bourhis to find any experiment in the history of science where length was
>> determined in the way he advocates.
>
Bourhis: >The definition of length used in [4] and precisely explained in [3]
is
>used routinely in GR for a very long time. Moller [5] described it in a
>book published in the 60's and it is therefore even older. It is a very
>general definition because it is equivalent locally to the kind of
>intuitive method you advocate which uses rulers
Dennis: So your desk having a different length CW than CCW is
"intuitive"--despite what you observe, despite what you measure, and despite
the way the rest of the planet measures length?
Bourhis: >Difficulties do only occur when one considers global properties,
Dennis: "Difficulties do only occur" for the theory you advocate. No
"difficulty" occurs for the ether analysis--or for sound Sagnac. And it is
absolutely no problem to measure the distance around a square or circle by
rulers. Engineers, architects, and scientists do it all the time without the
slightest bit of problem at all. The problem only occurs for your theory. So
you have to throw out this obvious measuring method that everyone uses, that is
completely natural, that relies on commonsense definitions of length, and that
you yourself agreed to within the last two weeks--not because engineers or
architects or scientists have a "difficulty" in making the measurement--but
because relativists have a "difficulty" reconciling that obvious measurement
with their theory.
B: And yes this is a new effect
>predicted by Special Relativity and LET but not by Galilean Relativity.
>But how is it possible to be surprised by this fact ?
Dennis: Actually, I would be very surprised to find out that my desk is longer
CW than CCW--as I think most people would. Apparently, you should have been
too because you agreed that it's the same length in both directions two weeks
ago. However, I'm not surprised people are willing to believe that desk is
longer CW than CCW (despite what they measure) in defense of a theory they
advocate.
D: >> It is a length that can only be
>> determined based on theoretical assumptions, i.e., by putting pen to
>paper--and
>> it is a length that *contradicts* what is actually observed by real
>> experimenters using real stationary rulers.
>
B:You are again completely confused. An observer moving infinitely slowly
>along the rim will measure the perimeter:
> L = 2 pi R/(1-(R Omega)^2)^(1/2)
>in units where c=1. But this is not the length of a light ray
>propagating along the rim in the non-inertial frame I have defined
>precisely above. Now how do you propose to measure with rulers the
>length of a light ray ?
Dennis: When you measure the average speed of something that moves from one
point to another (in your frame)--all scientists and engineers measure the
distance between the points (according to your frame) and divide by the time of
travel. I explained this for a week, showing how you glue rulers around the
rim to measure the path. You accepted this incredibly obvious method of
distance measurement that all scientists and all engineers use.
What happened since then?
Do you think it's reasonable to change such reasonable measurement methods
simply because you have since found it that it poses a problem for a theory you
want to advocate?
Don't you think it's more reasonable to abandon the theory--not the universally
accepted and reasonable measurement method?
Dennis McCarthy
Dennis McCarthy
>> A clock has nothing to do here - a coincidence indicator does the job. What
>> d'you mean by "the same speed"? D'you postulate it? If so, it's exactly the
>> same unanswered question (2).
>
Berry: >No, our observers measure it. They, for some strange reason, are under
the
>impression that the speeds they measure with their clocks and rulers are
>the actual speeds in their frame.
>
>I suppose _you're_ going to say that their measurements are invalid for
>some reason now, aren't you...
Dennis: I'm not sure what is meant here. The rim observer using stationary
rulers and a single stationary clock (or just a "coincidence indicator")
clearly measures anisotropy.
It is the relativists who want to argue that the distance measured by the
stationary rulers is actually wrong--and hypothesize that there are
unobservable deformations of the path that make it different CW than CCW.
It would seem to be that if your theory has a difficulty with a well-known
standard, intuitive, logically consistent, universal measurement method--it's
not the measurement method that should be abandoned.
Dennis McCarthy
Dennis McCarthy
>>
>>>Dennis: Are you trying to argue that R&T's position regarding
>>>the Sagnac effect was *not* that the "path becomes, in the
>>>course of the ring's rotation, different for the clock-wise
>>>and the anti-clockwise waves"--even for the rim observer?
>>
>Chan: Why on Earth would I be trying to argue that? Let's see now,
>>you're saying that R&T are saying that the path lengths are
>>different due to the absolute rotation of the ring. Gosh,
>>what an insight. How mysterious! Actually, that's what I
>>(and everyone else, as far as I can tell) have been saying
>>all along, including the reference web page, which says "Notice
>>that this anisotropy ... for any inertial frame is actually
>>in the distance travelled, not the speed of travel",
>
>Dennis: Perhaps, you should read the paper again? R&T are arguing the
>distance
>is different according to the frame **for the rim observer**--for the frame
>of
>the rim. That means the desk your computer is on would be longer CCW than
>CW--according to *you*--who is stationary wrt the desk despite what you
>measure.
That last sentence may seem confusing.
It should read: "That means the desk your computer is on would be longer CCW
than
CW--according to *you*--who is stationary wrt the desk. This is true despite
the fact that you obviously measure the same length CW as CCW."
Dennis McCarthy
Dennis McCarthy
>
>Dennis McCarthy wrote:
>>
>> >
>> >On Wed, 8 Mar 2000 19:15:16 +0000, Mark Samokhvalov wrote
>> >(in message <8a68pl$utl$1...@gavrilo.mtu.ru>):
>> >
>> >Before defining you as an etherist, you have to precise clearly what ether
>> >theory you want to use to model a Sagnac experiment. Be careful because in
>> >order to escape the difficulties encountered with SR, you have to avoid
>> >LET-like theories which have Lorentz transforms embedded in them.
>>
>> Dennis: You are coming close to outright dishonesty. The only person in
>the
>> world who follows the type of LET that you use to confuse situations and
>> complicate Sagnac is you. All other known etherists (Michelson, Sagnac,
>Ives,
>> etc., and those on these boards and all whom I know personally), no matter
>what
>> the ether theory, derive the Sagnac effect quite simply with the Galilean
>> analysis.
>
>experimentaly if you advocate a mere Galilean analysis of the Sagnac
>effect.
>Indeed,
>1) Are you really ready to promote LET for Michelson & Morley, Kennedy &
>Thorndike, Trouton & Noble, ..... while you advocate a Galilean analysis
>as the fundamental theory for Sagnac ?
Dennis: That statement is so shocking one wonders if you even read at all what
I wrote. Let me repeat the conclusion: Thus, (even for Lorentzian etherists)
the Galilean nature of light is clearly recovered in the experiment--because
there are no relevant deformations of the measuring devices to counteract this
Galilean nature. And **all** etherists whom I know
believe in the underlying Galilean nature of light.
Bourhis: >2) Or is it that a Galilean analysis is a good approximation of LET
when
>it comes to compare the theoretical predictions with the experimental
>results of light Sagnac experiments ?
>3) But then what about the experiments made with massive particles for
>which this Galilean analysis is completely wrong ? How do you treat this
>case ?
Dennis: The last case also involves ether waves--which is why you have
interference effects. When you have interference effects--you aren't hurling
two baseballs around the rim, your dealing with waves and the velocity of all
waves are independent of the speed of the source.
D:>> Now, unfortunately, the following involves physical reasoning, but
>I'll still
>> try. In the Sagnac effect, the Lorentz contraction can be disregarded by
>> Lorentzians because there is only one rim and so LC has an equal effect on
>both
>> path lengths. Also, no clock movements or synch procedures need to be
>made.
>> Thus, the Galilean nature of light is clearly recovered in the
>> experiment--because there are no relevant deformations of the measuring
>devices
>> to counteract this Galilean nature. And **all** etherists whom I know
>believe
>> in the underlying Galilean nature of light.
>
Bourhis: >Obviously not Lorentz.
Dennis: Regardless of this incorrect and irrelevant opinion, the argument above
stands.
D:>> Lorentzians apply the Lorentzian
>> corrections only when measuring devices are altered in a relevant way. If
>not,
>> then the Galilean nature is recovered, and as you know, I hope, it takes 3
>> lines of algebra to produce Sagnac.
>
B: >But you end up with a theory which has to treat differently light
>propagation, motion of clocks and motion of massive particles around the
>rim. On the contrary SR treats all these effects exactly in the same way
Dennis: SR, as you know, has 3 different explanations for sound Sagnac, light
Sagnac, and one way Sagnac. More it demands you abandon what you measure with
stationary rulers because it conflicts with theory. ( Massive particle
explanation is above. )
B: >and the results can also be derived in a few lines of algebra if one
>works in an inertial frame in which the rim is rotating.
Dennis: The theoretical difficulty of SR occurs for the analysis for the rim
observer.
B: And more
>importantly, this SR treats also with the same tools every experiments
>involving inertial frames, and in many cases (all MMX-line experiments),
>the result is a mere tautology.
Dennis: As with Lorentz-contraction theories, or IGS.
>
>> >But then
>> >you are most surely in trouble with Michelson & Morley, Kennedy &
>Thorndike
>> >or Doppler because an Ether theory compatible with these experiments is
>> >equivalent to SR as long as we are concerned with observable predictions.
>>
>> Dennis: That's false. Obviously. IGS theory, for example, fits the known
>> experiments. And Lorentz contraction does not need to be assumed.
>
B: >IGS postulate that the Earth is corotating with a vortex of Ether and
>therefore that the speed of a lab on Earth wrt Ether is tiny. But then
>you have to assume the consequences of this hypothesis: a vortex around
>the Earth corotating with the Moon, a vortex around Saturn corotating
>with its satellites. But wait the trajectory of these satellites are not
>in the same planes and their periods of rotation are very different. So
>does this leads to some observable effects related to the propagation of
>the light coming from these objects ?
Dennis: Yes. IGS clearly predicts a less than expected Sagnac effect for light
travelling around a system of satellites in the orbit of the moon. Indeed, IGS
clearly predicts you could absolutely find the absolute velocity of the
rotational velocity of the ether around the Earth by finding a place where a
system of rocketships cirlcing the Earth find a null Sagnac effect--despite
their revolution wrt the background stars. These rocketships would be at rest
(at least in the tangential direction) wrt the ether frame.
B:Or do you need one vortex for each
>satellite ? Same problem with Jupiter. And what about comets ?
Dennis: A well known description of general relativity is that "space tells
matter how to move, and matter tells space how to curve." If you replace the
word "space" with "ether," then this becomes, in fact, an acurate description
of Rado's ideal gas sink theory. Ether flows direct the motion of matter, and
material objects condition the curving motion of the ether flows. The stronger
the gravitational system the greater the vortex.
Bourhis: >And more importantly where is the complete exhaustive quantitative
>comparison of the prediction of IGS with the available relevant
>experimental data ? GR and SR predictions and their confrontation to
>experiments are reported in hundreds of papers published in widely
>available journals.
>There are even summaries of the current situation,
>cf [1] for example. So if you want to convince mainstream science you
>have to produce a work with the same quality. Can you do that ?
Dennis: All of the essentical SR predictions are duplicated by ether theory as
you should know. So far I've given inverse square and perihelions--for
gravitational effects. And even with the inverse square, an irrefutable and
very simple kinetic analysis has been unable to convince some "mainstream
physicists" on these boards despite their inability to challenge a single fact,
equation, or argument.
Dennis McCarthy
Tom Roberts
> Dennis: But what's astounding is that the global properties (the whole) does
> not equal the sum of the local properties (the parts.)
It's only "astounding" to someone who has not thought about it.
Example: One can approximate the circumference of a circle by placing
many short straight rulers around it. Consider, say, a circle with
1000 1-meter rulers lined up end-to-end around it. Is it "astounding"
that these rulers did not get 1000 meters away from the starting
point? After all, the total (whole) distance from the starting point
(zero) is NOT the "sum of its parts" (1000 m).
> This, of course, is a
> newly invented, complicated, counter-intuitive and bizarre principle--that must
> be believed on faith--in order to maintain allegiance to SR.
Not true at all. There's nothing new here which has not been
understood for hundreds of years -- circles are not straight lines
globally, but are locally (remember this is physics, not math).
> Dennis: You are claiming that c as the local speed of light is the *reality* of
> the underlying situation.
Apparently you have not read my article on this. I make no claim
whatsoever about "the *reality*" of anything. I merely describe how
one could use different coordinates (outlooks, points of view) to
obtain different descriptions of a single physical phenomenon.
> The real speed of the local speeds of light does not
> add up to average global speed--according to you.
You are completely incompetent to attampt to paraphrase what I say.
Please don't try. This is not a summary of what I have said,
and the situation is far more complex than you imply here.
I repeat: I have never discussed "the real" speed of light. And
there is no requirement that local speeds "add up" to an average
speed -- see above for an example where local distances do not
"add up" to a total distance. There are zillions of examples where
local properties differ significantly from global properties.
> Dennis: So the speed of light is isotropic for the rim
> observer--despite what he measures.
Again, it seems you have not read what I wrote. I gave several
different descriptions of how a "rim observer" could describe
this situation. And this involves several different results of
"what he measures", which depend upon _HOW_ he measures.
I repeat: when you insist on making such loosely-worded statements
it is no surprise that you come up with internally-inconsistent
claims.
> Dennis: R&T comes up with a global measurement of
> isotropy--contradicting your claim above.
I repeat: you seem completely incapable of reading what I wrote.
I gave several difference descriptions of this, using different
coordinates (measurement techniques). R&T used a still different
set.
Tom Roberts tjro...@lucent.com
Luc Bourhis
>
> To my knowledge, ALL experiments performed to detect the effect of the
> Earth's orbital velocity on physical processes, including my own to detect
> the anisotropy of electrophysical parameters induced by it, have produced
> nil results.
result have been shown to have systematic effects or their results have
not been reproduced.
> Together with the existence of star aberration, this could be
> explained by ether drag by the Earth's gravitational field and verified by
> any of the aforementioned experiments on board satellites, or on the Earth
> by such experiments sensitive enough to detect the effects of Earth's
> rotation velocity. Perhaps, such experiments have already been performed -
> any information?
So you believe that Ether is dragged not only by the translation of
Earth around the Sun but also by the rotation of Earth around its axis,
do you ? Then a purely Galilean Ether might not be ruled out by
experiments made on Earth surface but with this hypothesis you have
opened the Pandora box and you have to deal with every sin jumping out
of it. You need a vortex around each satellite of Saturn, embedded in a
vortex around Saturn, embedded in a Vortex around the Sun, and so on for
each planets and comets. What are the prediction for bending of light or
Shapiro time delay for example ? What about the GPS system ? In order to
save Ether, you have just created even more problem to solve. This is
quite typical and this is the reason why the concept has been
abandonned.
> >The 3 following objects have different length:
> >- the trajectory of a co-rotating particle
> >- the trajectory of a counter-rotating particle
> >- the rim
> >if one works in the non-inertial frame whose world lines are defined by the
> >following parametric equations in some inertial frame:
> > x0 = t
> > x1 = a cos(w t) - b sin(w t)
> > x2 = a sin(w t) + b cos(w t)
> > x3 = 0,
> >with (a^2+b^2)^(1/2) being the radius of the rim and w its rotation speed.
>
> Clearly, a case when sollipsism comes in conflict with reality - different
> results obtained by reasoning with no physical cause.
What is a physical cause ?
> SR was originally
> constructed not as a physical, but as a metric theory - had another signal
> carrier (e.g., fast particles) been used, the results would have been
> different.
You mean that the length of the trajectories would have been different,
do you ? You are right but what is funny is that the difference between
them does not depend on the speeds of the particles as long as they are
the same in the two opposite directions along the rim.
> Had different signal carriers been used jointly, all ambiguity
> (=relativity), would have been removed.
????
> Indeed, during the XX-th century triumphs of theoretical physics elated the
> intellectual elite aleready influenced by sollipsist philosophy to the
> extent that they thought they could construct reality.
Modern science *does model* reality. We works with mathematical
idealisation of the reality and not with the reality itself. This
process is not really new: it has started with Galileo.
> It the same with
> quantum physics: all sorts of weird hypotheses have been advanced to explain
> the interference of isolated quanta instead of aknowledging the simple fact
> of their division and propagation in the form of sub-quantum oscillations.
????
> >Again which Ether theory ? Anyway for the non-relativistic particles used
> >here, de Broglie law relating the wave-length lambda, and therefore the
> >energy of the particles, their mass m and their speed v,
> >lambda = h/(m v) is exceptionaly well verified. Then the two beams are obtained
> >from one incoming beam by a Bragg diffraction through a layer of silicon. The
> >optical
> >nature of the phenomena guaranties that the wave-length of the two outgoing
> >beams is the same. Therefore the situation is the one I have described and
> >you have only forced me to explain the details related to my remark between
> >parentheses. Note that the same kind of experiments have been made with
> >electrons [7] (thanks to Tom Roberts for the reference).
> >
> >So now how can you explain the experimental results ?
>
> >The experimental fact of inertial mass vs V dependence explained/predicted
> by several theories, includung SR. With the ether concept, V is measured wrt
> ether, and therefore in the ring's RF it will be different for co- and
> counter-rotating equal energy particles.
I repeat that the particle are not relativistic here. Therefore we have
plain Newtonian physics for the definition of mass, momentum and energy.
Please read again my argument:
> >What is tremendously interesting however is that one finds the same T for
> >this shift between clocks and for the delay between the arrival time of
> >particles rotating in opposite direction even if a priori there is no links
> >between these two configurations. If one remembers that the same geometry of
> >spacetime is at work, everything becomes clear and indeed the important point
> >is of course that SR gives the correct predictions for all these effects. And
> >Ether theories ?
>
> No space-time needed. Suffice it that both effects are described by small
> terms quadratic in V. Integration over travel time produces the result.
Please show the details. For SR/GR you have them in the references given
by me and others in this thread.
> >I do not understand : do you say the the equivalence principle can be
> >believed or that it is ruled out ? I do not know any experimental data
> >supporting the latter.
> >
> I mean, it doesn't work, because the clocks on satellites at different
> altitudes tick differently.
Why does this contradict the equivalence principle ?
[1] Brillet et Hall, Phys. Rev. Lett. 42 (1979) 549
[2] Champeney et al: it is described in Classical Electrodynamics by
Jackson.
Dennis McCarthy
>> results obtained by reasoning with no physical cause.
>
Dennis: It seems that degrees in Unintended Irony has really paid off. ;-)
Dennis McCarthy
z@z
:: = Mark Samokhvalov
:: Together with the existence of star aberration, this could be
:: explained by ether drag by the Earth's gravitational field and verified by
:: any of the aforementioned experiments on board satellites, or on the Earth
:: by such experiments sensitive enough to detect the effects of Earth's
:: rotation velocity. Perhaps, such experiments have already been performed -
:: any information?
Stellar aberration is inconsistent with a simple materialistic ether.
http://www.deja.com/=dnc/getdoc.xp?AN=526082799
There are two obvious hypotheses for an "ether drag by the Earth's
gravitational field":
1) The whole ether follows the earth's gravity center.
2) The ether is dragged by all matter systems (particles) proportionally
to their mass and inversely to the distance square (between ether point
and ether-dragging particle).
The first hypothesis results in an earth rotation induced ether drift
of exactly the (sidereal) rotation velocity (356 m/s for the experiment
of Brillet and Hall). In the case of a Michelson-Gale experiment, the
result is the one which Michelson and Gale claim to have found.
The second hypothesis (based on a weighted average of all "ether drags")
results (apart from a non-negligible sun induced component) in around
60% of the earth's rotation speed (200 m/s for Brillet & Hall). In the
case of Michelson-Gale, the result is the one predicted by SR in the case
of an earth rotation speed of only 60% of its actual value.
Brillet and Hall have reproduced (1978) the result found by Jaseja (1964),
consistent with an earth rotation induced ether drift of around 200 m/s.
http://www.deja.com/=dnc/getdoc.xp?AN=524152873
http://www.deja.com/=dnc/getdoc.xp?AN=527095025
The thesis of a (relational) ether dragged by all matter according to
the inverse distance square law predicts for a Sagnac experiment over
the equator not the light speeds c + 464 m/s from east to west and
c - 464 m/s from west to east as SR does, but around c + 270 m/s from
east to west and c - 270 m/s from west to east.
: So you believe that Ether is dragged not only by the translation of
: Earth around the Sun but also by the rotation of Earth around its axis,
: do you ?
No, on the surface of the earth the ether is only partially (about 40%)
dragged by the earth's rotation.
One should never forget that a dragged ether has been ruled out only for
theoretical reasons (based on certain premises), and not because of
experimental refutation!
I know of no CONVINCING experiments, which disprove such an ether. One
can also easily understand, why SR works as an excellent approximation.
Up to a distance of around 260'000 km, the ether is primarily dragged by
the earth, whereas in most regions of our solar systems it almost fully
follows the (movement of the) sun.
Wolfgang Gottfried G.
Dennis McCarthy
>
>Dennis McCarthy wrote:
>> Dennis: But what's astounding is that the global properties (the whole)
>does
>> not equal the sum of the local properties (the parts.)
>
>
>Example: One can approximate the circumference of a circle by placing
>many short straight rulers around it. Consider, say, a circle with
>1000 1-meter rulers lined up end-to-end around it. Is it "astounding"
>that these rulers did not get 1000 meters away from the starting
>point?
Dennis: No. That's not astounding. It's not even strange.
But here's what would be. If in every 10 miles of a trip from NY to Albany,
you averaged 50 MPH--yet your average velocity for the whole trip was 70
MPH--now, that's a little strange, wouldn't you say?
The average velocity of light for each leg is c, yet the average for the
whole leg is c+v? Are you kidding?
>> This, of course, is a
>> newly invented, complicated, counter-intuitive and bizarre principle--that
>must
>> be believed on faith--in order to maintain allegiance to SR.
>
Roberts: Not true at all. There's nothing new here which has not been
>understood for hundreds of years --
Dennis: Hmm. Then one wonders what R&T had to correct the interpretations of so
many relativity papers--and even comments like you have made recently.
>> Dennis: You are claiming that c as the local speed of light is the
>*reality* of
>> the underlying situation.
>
Roberts: >Apparently you have not read my article on this. I make no claim
>whatsoever about "the *reality*" of anything.
Dennis: That goodness, because I don't think it's your long suit.
>> The real speed of the local speeds of light does not
>> add up to average global speed--according to you.
>
Roberts: >You are completely incompetent to attampt to paraphrase what I say.
>Please don't try. This is not a summary of what I have said,
>and the situation is far more complex than you imply here.
>
>I repeat: I have never discussed "the real" speed of light. And
>there is no requirement that local speeds "add up" to an average
>speed --
Dennis: Um, first-year-algebra meet Roberts. Roberts, first year algebra.
If an object moves the same average local speed for all segments, of course,
this equals the average global speed as well. In order to elude this obvious
fact, you have to start playing with time or distance based on an assumption of
a constant c (which is of course the value you are trying to measure--so this
is circular.)
see above for an example where local distances do not
>"add up" to a total distance.
Dennis: Um, the local lengths of the circle do add up to the total length of
the circle. The distance from the starting point does not equal the total
length of the circle because the segments were angled back so they returned to
the same spot. Wow.
There are zillions of examples where
>local properties differ significantly from global properties.
Dennis: Not if you don't make silly 3rd grad e mistakes. I think it's pretty
clear that if an object moves the same average local speed for all segments, of
course, this equals the average global speed as well.
>> Dennis: So the speed of light is isotropic for the rim
>> observer--despite what he measures.
>
Roberts: >Again, it seems you have not read what I wrote.
Dennis: I was referring to R&T's explantion.
Roberts: I gave several
>different descriptions of how a "rim observer" could describe
>this situation. And this involves several different results of
>"what he measures", which depend upon _HOW_ he measures.
Dennis: I like the one where he actually uses stationary rulers and one
stationary clock. How about you?
Roberts: >I repeat: when you insist on making such loosely-worded statements
>it is no surprise that you come up with internally-inconsistent
>claims.
Dennis: Perhaps, this is the reason for your two inconsistent statements below:
Roberts (one day): "In these coordinates the _average_ speed of light
_going_all_the_way_around_the_ring_ is different for the two directions, but
the distance is the same for both rays.
Again there is no mystery -- the light rays travel the same distance at
different average speeds and therefore accumulate
a phase difference."
Roberts (the next day): ">One can take the sum of the rulers laid around the
rotating rim and divide it by the time taken for a light pulse to
circumnavigate the
>rim (measured on a single clock).
But as R&T showed, this is not really "distance"/"time", this is really
"distance plus an admixture of time"/"time", and
calling it "speed" is really a misnomer."
See how one day, according to you, you can use stationary rulers divide by time
and call it "speed"--and the next day you suddenly realize you can't really
trust those darn stationary rulers--and so "calling it "speed' is really a
misnomer."
Geez, I thought all of this was so simple and that people knew about this for
100 years. ;-)
Dennis McCarthy
Robert Chan
>Perhaps, you should read the paper again? R&T are arguing
>the distance is different according to the frame **for the
>rim observer**--for the frame of the rim.
You're making the same mistake Selleri made, the one that R&T
corrected in their paper. The whole message of R&T's paper
is that Selleri was mistaken in assuming the existence of a
coherent frame of reference covering the entire disk, with
respect to which the instantaneous (local) speed of light is
anisotropic. R&T correctly explained that this premise is
false, and that the correct application of the principles of
special relativity does not lead to an anisotropic ratio of
light speeds, regardless of the size or speed of the disk.
Therefore, Selleri's concern about a "discontinuity" in the
anisotropic speed ratio as the disk radius increases (while
holding the rim speed constant) was unfounded. The R&T paper
demonstrated the (well known) fact that, applying the principles
of special relativity correctly and consistently, the difference
in transit times in a Sagnac device is due to the difference in
optical path lengths for the counter-rotating and co-rotating
beams, not due to any anisotropic light speed.
Of course, Tartaglia would agree that when staying on board a
turning disk and slowly (quasi-statically relative to the disk)
"pacing off" the length of the rim of the disk we will obtain
the same distance both clockwise and counter-clockwise. On the
other hand, when standing at one point of the rim with a single
clock and measuring the time of flight for light in the two
directions we will obtain two different values. Consequently
when calculating the ratio of length (based on slowly pacing
around the perimeter) over time (based on the light travel
intervals by a single clock on the rim), we get two different
numbers and, since space over time is a "velocity", we might
say that the "speed of light" in one direction is different
from the "speed" in the other.
HOWEVER, this trivial result in no way contradicts special
relativity (nor does it contradict any of the numerous other
coordinate systems in terms of which a Sagnac device can be
described in accord with relativity). The invariance of the
speed of light in SR simply means, geometrically speaking,
that the slope of the world lines of light, in Minkowski space
time, is always 45 degrees (provided the same units are used
for space and time). A space time diagram drawn for the
rotating disk easily shows that, by construction, corotating
and counter-rotating light beams always have a 45 degree
slope and this produces no strange or contradictory result
whatsoever.
It's just silly to make a fuss over the Sagnac effect, which
is a rather mundane and essentially classical phenomenon.
There's nothing mysterious about it, at least not to anyone
who understand it. You've been given all kinds of references,
complete with pictures and careful explanations, taking many
different approaches, all leading to exactly the same obvious
conclusions. The only thing mysterious about this is why you
would continue to waste your time making a fool of yourself
over this.
Luc Bourhis
(in message <20000309110513...@ng-cg1.aol.com>):
>> 1) Are you really ready to promote LET for Michelson & Morley, Kennedy &
>> Thorndike, Trouton & Noble, ..... while you advocate a Galilean analysis
>> as the fundamental theory for Sagnac ?
>
> That statement is so shocking one wonders if you even read at all
> what
> I wrote.
This was a question .... and your following answer proves that it was a
relevant one.
> Let me repeat the conclusion: Thus, (even for Lorentzian etherists) the
> Galilean nature of light is clearly recovered in the experiment--because
> there are no relevant deformations of the measuring devices to counteract
> this Galilean nature.
Are you seriously writing that the arm of a Michelson interferometer is
affected by the ether wind, both for time and length measurement, while a
given small section of the rim is not ? This is utterly incoherent.
>> 2) Or is it that a Galilean analysis is a good approximation of LET when
>> it comes to compare the theoretical predictions with the experimental
>> results of light Sagnac experiments ?
>> 3) But then what about the experiments made with massive particles for
>> which this Galilean analysis is completely wrong ? How do you treat this
>> case ?
>
> Dennis: The last case also involves ether waves--which is why you have
> interference effects. When you have interference effects--you aren't hurling
> two baseballs around the rim, your dealing with waves and the velocity of all
> waves are independent of the speed of the source.
You are blatantly wrong. Do not forget that the group velocity of the wave
functions must behave as the classical speed of the associated particles.
Therefore if a massive particle A produces two massive particles B and C, the
conservation of momentum implies necessarily that the speeds of B and C
depends on the speed of A. Your mistake was to believe that wave functions
have the properties of usual material waves.
Therefore in a Sagnac experiment with neutrons, one has actually particles
moving in opposite directions with the same speed with respect to the rim
(this can be verified experimentally) and a Galilean analysis is refuted
experimentally. How do you solve this problem ?
>> But you end up with a theory which has to treat differently light
>> propagation, motion of clocks and motion of massive particles around the
>> rim. On the contrary SR treats all these effects exactly in the same way
>
> Dennis: SR, as you know, has 3 different explanations for sound Sagnac, light
> Sagnac, and one way Sagnac.
What do you mean by one-way Sagnac ? Anyway let me be clearer: SR treats in
the same way the propagation of a signal or the motion of a body with a
velocity v wrt to the rim, whatever is the value of v. One can makes once and
for all the analysis for any value of v. On the contrary, your galilean
argument gives good approximations for light and sound but it failed to
explained the desynchronization of clocks moving around the rim and to treat
correctly massive particles. You need a theory like LET to analyze the last
two effects.
> More it demands you abandon what you measure with stationary rulers
> because it conflicts with theory.
No.
> ( Massive particle explanation is above. )
No.
>> and the results can also be derived in a few lines of algebra if one
>> works in an inertial frame in which the rim is rotating.
>
> Dennis: The theoretical difficulty of SR occurs for the analysis for the rim
> observer.
Yes but one is allowed to be clever. Practically the analysis in the lab
frame is as easy as your Galilean one while being more general, as explained
above.
and you have also written in an another thread:
>> This comes from the fact that
>> neither the rim nor the light rays are well defined geometrical objects
>> entirely embedded in space at a given instant.
>
> Ether theories don't have this problem with hypothesizing an
> *unobservable* problem with geometrical objects entirely embedded in space
> at a given instant.
But then if you want to compete with SR, you have to find an Ether theory
that can account for
- light Sagnac
- desynchronization of clocks moving along the rim
- Sagnac with massive particles moving with the same speed in opposite
direction
If your proposal is not the superposition of contradicting models, the
analysis in the frame of the rim is as difficult as in SR. Do you want to try
to come with such a theory ?
>> And more importantly, this SR treats also with the same tools every
>> experiments involving inertial frames, and in many cases (all MMX-line
>> experiments), the result is a mere tautology.
>
> Dennis: As with Lorentz-contraction theories, or IGS.
Yes.
> And **all** etherists whom I know believe in the underlying Galilean
> nature of light.
and also in another thread
>> This is a definitive result of SR and/or GR, and of course of LET
>
> Dennis: Please stop confusing your idiosyncratic views of a 1904 paper with
> ether theories followed today. I have asked you many times to stop this.
What is your point ?
Do you claim that LET is not equivalent to SR ? That it does still predict
some observable Galilean effects ? By LET I mean Lorentz's theory of
electrons, the last version of which was presented in 1904. Then you are
contradicted by Lorentz himself. Read my last contribution to the endless
discussion I have with greywolf (subject "Re: Step by Step, SR and LET")
where I give extensive citations of Lorentz showing that he has already
started to embraced Einstein's point of view in 1905 whereas he advocated
Special Relativity as better than his own theory in 1915.
Do you consider that LET is not interesting anymore nowadays ? You had better
to be careful because there are not a lot of alternatives:
- if there is an Ether wind faster than, let's say a few 100 m/s, in lab
frames on Earth, then Ether theories with embedded Lorentz transforms are the
only viable solutions, as demonstrated by Robertson [1] and reminded so often
by Tom Roberts
- if the Ether wind is slow enough, you have to devise a model explaining
this situation. Until now I have seen only what you call IGS and this subject
is discussed just below.
>>>> But then you are most surely in trouble with Michelson & Morley,
>>>> Kennedy & Thorndike or Doppler because an Ether theory compatible with
>>>> these experiments is equivalent to SR as long as we are concerned with
>>>> observable predictions.
>>>
>>> Dennis: That's false. Obviously. IGS theory, for example, fits the known
>>> experiments. And Lorentz contraction does not need to be assumed.
>>
>> IGS postulate that the Earth is corotating with a vortex of Ether and
>> therefore that the speed of a lab on Earth wrt Ether is tiny.
I realize that I was not precise enough. In order to be compatible with
experimental results ˆ la Brillet et Hall, IGS needs to postulate that the
Earth is surrounded by the superposition of two vortices: one corotating with
the Earth around its axis and one corotating with the Earth around the Sun.
In such a way the ether wind in a lab fixed on the surface of Earth is zero.
>> But then you have to assume the consequences of this hypothesis: a vortex
>> around the Earth corotating with the Moon, a vortex around Saturn
>> corotating with its satellites. But wait the trajectory of these
>> satellites are not in the same planes and their periods of rotation are
>> very different. So does this leads to some observable effects related to
>> the propagation of the light coming from these objects ?
>
> Dennis: Yes. IGS clearly predicts a less than expected Sagnac effect for
> light travelling around a system of satellites in the orbit of the moon.
> Indeed, IGS clearly predicts you could absolutely find the absolute
> velocity of the rotational velocity of the ether around the Earth by
> finding a place where a system of rocketships cirlcing the Earth find a
> null Sagnac effect--despite their revolution wrt the background stars.
> These rocketships would be at rest (at least in the tangential direction)
> wrt the ether frame.
Why these effects have not been seen with Moon ranging, GPS or Shapiro time
delay ?
>:->
Kirk: Evaluation of the probability of hand waves, Mr. Spok.
Spok: 99.997 %, captain
>:->
>> Or do you need one vortex for each satellite ?
>> Same problem with Jupiter.
>> And what about comets ?
The above correction raises even more question: is is possible to have at the
same time a vortex corotating with Saturn around its axis and a vortex for
each of its satellite, none of them rotating at the same speed ? You need a
steady flow. Is this possible ? This is very unlikely and you need to check
this point before using IGS as a serious argument.
> Dennis: A well known description of general relativity is that "space tells
> matter how to move, and matter tells space how to curve." If you replace
> the word "space" with "ether," then this becomes, in fact, an acurate
> description of Rado's ideal gas sink theory. Ether flows direct the
> motion of matter, and material objects condition the curving motion of the
> ether flows. The stronger the gravitational system the greater the
> vortex.
Nice hand waves but can we see a complete, coherent, quantitative theory
based on these ideas ? If not, I am not interested.
>> And more importantly where is the complete exhaustive quantitative
>> comparison of the prediction of IGS with the available relevant
>> experimental data ? GR and SR predictions and their confrontation to
>> experiments are reported in hundreds of papers published in widely
>> available journals.
>> There are even summaries of the current situation,
>> cf [1] for example. So if you want to convince mainstream science you
>> have to produce a work with the same quality. Can you do that ?
>
> All of the essentical SR predictions are duplicated by ether
> theory as you should know.
Not really. I am still waiting for a demonstration of Maxwell equations from
the hydrodynamics of an inviscid Ether for example. Moreover the only thing
you have is that sound clock experienced time dilatation. How do you
generalise this results to mechanical clocks, atomic clocks, particles
decaying through weak and strong interaction without adding an additional
layer of postulates ?
> So far I've given inverse square and
> perihelions--for gravitational effects. And even with the inverse square,
> an irrefutable and very simple kinetic analysis has been unable to
> convince some "mainstream physicists" on these boards despite their
> inability to challenge a single fact, equation, or argument.
We have endlessly explained to you that the distribution of speeds you have
chosen for Ether particles in your model is not realistic. We have cited
results contradicting the predictions of your model. We are still waiting for
a serious answer to these criticisms.
[1] M. Visser, gr-qc/9712010
Luc Bourhis
(in message <20000309102259...@ng-cg1.aol.com>):
>> Now consider two slow moving clocks C+ and C-, respectively co- and
>> counter-rotating. If they are synchronized with a clock at point A, when
>> they come back to A, C+ and C- are respectively late and ahead with
>> respect to A and the difference between their reading is exactly the
>> above time delay T.
>>
>> This shows clearly that there is much more than a speed anisotropy at
>> work in Sagnac experiments, "
You have quoted only one half of my argumentation: I have also looked at
Sagnac effect with two particles moving in opposite directions with the same
speed wrt the rim. The fact that the delay between the comebacks of these
particles is also the time shift between the above two clocks after a
round-trip is a strong hint that there is a hidden property of the rotating
rim behind all these phenomena. Since the anisotropy of light propagation is
not involved in these two examples, my conclusion is sound.
> Obviously, your argument involving changing clocks cannot rule out the
> possibility that speed anisotropy can the cause of the Sagnac effect.
> This is true because open-air sound clocks
^^^^^^^^^^^^^^^^^^^^^
A very strong assumption, indeed, because the clock one uses in order to do
actual experiments are not the light clocks which are the equivalents of your
sound clocks.
> moving around a rotating rim
> experience the same effect as described in your premise--and speed
> anisotropy is what causes the sound Sagnac.
> A cannot entail B when I show an instance where A is true and B is false.
Nice sophisms but my physical analysis was much more interesting.
>> Sun-Tzu said : "When involved in a guerilla, launch first the attacks
>> which do not cost you anything".
>
> Dennis: I think we should be on an objective search for the truth, not a
> guerilla attack.
_the_ truth ? Sun-Tzu said : "Those who fight a jihad are the weakest and the
strongest opponents at the same time" ... and this time I do not forget ;-)
>> An observer moving infinitely slowly along the rim will measure the
>> perimeter:
>> L = 2 pi R/(1-(R Omega)^2)^(1/2)
>> in units where c=1. But this is not the length of a light ray
>> propagating along the rim in the non-inertial frame I have defined
>> precisely above. Now how do you propose to measure with rulers the
>> length of a light ray ?
>
> Dennis: When you measure the average speed of something that moves from one
> point to another (in your frame)--all scientists and engineers measure the
> distance between the points (according to your frame) and divide by the
> time of travel. I explained this for a week, showing how you glue rulers
> around the rim to measure the path. You accepted this incredibly obvious
> method of distance measurement that all scientists and all engineers use.
> What happened since then?
This procedure gives the length of the rim but not the length of light rays
or of particles trajectories rotating along the rim.
> Do you think it's reasonable to change such reasonable measurement methods
> simply because you have since found it that it poses a problem for a
> theory you want to advocate?
The measurement methods have not been changed. On small portions of the rim
they are still what they have always been. One has simply to be careful when
one has to glue together all these infinitesimal measurements.
> Don't you think it's more reasonable to abandon the theory--not the
> universally accepted and reasonable measurement method?
For the 666th time, please come with an alternative as general and well
supported by experimental evidences than SR and we will discuss again this
point.
[1] H.P. Robertson, Rev. Mod. Phys., 21 (1949) 378
Dennis McCarthy
>On 09 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>>Perhaps, you should read the paper again? R&T are arguing
>>the distance is different according to the frame **for the
>>rim observer**--for the frame of the rim.
>
>is that Selleri was mistaken in assuming the existence of a
>coherent frame of reference covering the entire disk, with
>respect to which the instantaneous (local) speed of light is
>anisotropic. R&T correctly explained that this premise is
>false, and that the correct application of the principles of
>special relativity does not lead to an anisotropic ratio of
>light speeds, regardless of the size or speed of the disk.
Dennis: Exactly and finally. And since we know via the fringe shifts (or via
single clock) that the two rays take a different amount of time to travel CW
and CCW around the rim (according to the rim observer)
this...means...the...distance..is...different....for...the...two...differe
nt...directions around the rim--according to the rim observer.
Chan: >It's just silly to make a fuss over the Sagnac effect, which
>is a rather mundane and essentially classical phenomenon.
>There's nothing mysterious about it, at least not to anyone
>who understand it.
Dennis: Well we don't have to use the term "mysterious." But the belief that
the desk your computer is on is longer CCW than
CW--according to *you*--who is stationary wrt the desk--seems a little
artificial, don't you think? That's certainly not what you measure. And it
seems strange to reject what you measure (using a well known, universally
accepted, and logical measuring scheme)--simply because it doesn't coincide
with a theory you want to advocate.
Dennis McCarthy
Dennis McCarthy
>> Let me repeat the conclusion: Thus, (even for Lorentzian etherists) the
>> Galilean nature of light is clearly recovered in the experiment--because
>> there are no relevant deformations of the measuring devices to counteract
>> this Galilean nature.
>
is
>affected by the ether wind, both for time and length measurement, while a
>given small section of the rim is not ? This is utterly incoherent.
Dennis: Your confusion on so many issues is so great that communication with
you is very laborious.
Lets define Galilean as the fact that if the actual speed of light is c in
frame S, then the actual speed of light in S' (where S' is moving at v wrt S)
is c+v, okay?
Now, what don't you understand about MM?
It's one frame and the **measured** speed of light was close to isotropic.
So where did you lose Galilean relativity here?
Bourhis: >Therefore in a Sagnac experiment with neutrons, one has actually
particles
>moving in opposite directions with the same speed with respect to the rim
Dennis:Sigh. If the objects are moving at the same speed wrt the rim, then
they move around the rim in the same amount of time. That's tautological.
B: >(this can be verified experimentally) and a Galilean analysis is refuted
>experimentally.
Dennis: Another bizarre confusion.
Dennis McCarthy
Dennis McCarthy
>>> More it demands you abandon what you measure with stationary rulers
>> because it conflicts with theory.
>
Dennis: According to the R&T explanation of Sagnac is the distance around the
rim the same CW as CCW?
Is that what you measure with stationary rulers?
Dennis McCarthy
jddescr...@my-deja.com
djm...@aol.com (Dennis McCarthy) wrote:
> Roberts: > In these coordinates the _average_ speed
> >of light _going_all_the_way_around_the_ring_ is different for
> >the two directions, but the distance is the same for both rays.
> >Again there is no mystery -- the light rays travel the same
> >distance at different average speeds and therefore accumulate
> >a phase difference.
>
the
> average of all the speeds for each small segment of the trip. Anyway,
R&T
> rejected such explanations via Selleri years ago.
> Allegedly, according to the rim observer, the speed of light is still
> anisotropic--despite what his rulers and clock reads.
>
> Roberts: Note that it is tricky to define "speed of light"
> > in these coordinates,
>
> Dennis: Not for etherists.
>
> but there is indeed a well-defined
> > _average_ speed of light _going_all_the_way_around_.
> > This is intimitely related to the difficulty of
> > synchronizing clocks in a rotating system....
>
> Dennis: No difficulty for etherists.
>
> Dennis McCarthy
>
>
---------------------------------------------------------------------
Congratulations Dennis! You are making real progress
on your crusade to bring physical reality truths to
this forum! It may be hard for you to see, from close
up, since you have been trying to teach the same,
powerful, consistent lesson to the same people for
many moons. As an outside observer I can see that you
have made rather remarkable progress. First we have
to divide the SR deceived into two groups . The one
group, that believes in mystic,magic king's men of
science [KMS] decrees are a lost cause. They will be
quoting the same KMS slogans they memorized forever
until the KMS change the decrees. As you have commented
this, historically, takes a long time in science. They
will repeat the king's chant they are paid auf to recite
with no interest in the truth. The other group is what
I've called the Special Relativity [SR] Contractionists.
They honestly believe, the case you are discussing here,
that a continuous, linked measuring rod will measure a
different distance going left than going right on a
closed path. When I first heard you identify their
deception, so clearly, I couldn't believe it was their
true state of confusion but, again, this thread
demonstrates it convincingly.
Now the good news where I can see your teachings are
beginning to get through. They [the second group] are
still in denial but with a much more humble tone. First
they are admitting that they use multiple coordinate
frames to get their "answers" so what they mean by a
measurement is not what any good scientist has ever
meant before. Second they are talking about the actual
average process that they use on the measurements. This
is in sharp contrast to the past where they used
conventional terminology for obtuse definitions. Third,
by confining your example to the Michelson/Gale Sagnac
experiments it is clear exactly what speed in the vacuum
is being discussed and that any apparent complications
due to a rotating/accelerating path are second order and
have an entirely negligible effect on the predicted
result. They are still confusing transient and continuous
measurments but you can watch for this confusion. Keep up
the good work. The scientific truth is worth the efforts
and frustrations of teaching such slow learners. I'm not
the only one who appreciates your valiant efforts! Your
good teachings may not show up in this current version of
the Relativity FAQ but be assured they eventually will.
Scientific truth always outs - EVENTUALLY!
Good seeing. JD
----------------------------------------------------------------------
Sent via Deja.com http://www.deja.com/
Before you buy.
Robert Chan
>RChan: >You're making the same mistake Selleri made, the one
>>existence of a coherent frame of reference covering the
>
>Dennis: Exactly and finally.
Good, I'm happy that you finally agree you were making the same
mistake as Selleri. Let's see how long your moment of clarity
lasts.
On 10 Mar 2000 Dennis McCarthy wrote:
>And since we know ... the two rays take a different amount
>of time to travel CW and CCW around the rim ...this means
>the distance is different for the two different directions
>around the rim--according to the rim observer.
Gosh, that moment of clarity didn't last long. In one sentence
you acknowledge that you were erroneously assuming, like Selleri,
the existence of a coherent frame of reference covering the
entire disk, and in the next sentence you emphatically re-assert
the same erroneous assumption.
On 10 Mar 2000 Dennis McCarthy wrote:
>...the belief that the desk your computer is on is longer CCW than
>CW--according to *you*--who is stationary wrt the desk--seems a
>little artificial, don't you think?
No, quite the contrary. I regard significantly accelerating systems
of reference as a little artificial, especially for evaluating
physical phenomena (such as the progress of two counter-rotating
beams of light around a ring), because I understand that the most
natural decomposition of spacetime is with respect to the inertial
frame in which I am presently at rest at any given instant, and so
my acceleration causes a continuous change in the natural space and
time decomposition.
On 10 Mar 2000 Dennis McCarthy wrote:
> That's certainly not what you measure.
It's not?? You just said it WAS. It sounds like you're having
trouble distinguishing between two different measurements, and this
difficulty stems from your inability to grasp spacetime as a unified
four-dimensional manifold. You're looking at various 3D projections
of 4D paths, and drawing erroneous conclusions from these projections.
The slow pacing method of measuring a spatial distance consists of
a number of disjoint spacelike intervals (the size of your foot)
paired up sequentially with physically contiguous segments of the
rim. On the other hand, the lightbeam method of measuring (or
comparing) spatial distances consists of the spatial project a
continuous null helical path of light through spacetime onto some
spatial axis. With respect to any inertial coordinates we can easily
do this on the same basis for both beams, but if (for some reason)
we insist on projecting the light path onto a system of reference
that is continuously changing its inertial frame in one particular
direction (by rotating in that direction), it's hardly surprising
that this yields unequal spatial projections for the two beams of
light, one moving in the same direction as my rotation, and the other
moving in the opposite direction. These two methods are measuring
two different things.
You're dissatisfied with the fact that two measurement procedures
give different results, because you don't see that they are measuring
different things (apparently because the difference involves the 4th
dimension, which you seem unable to grasp). I'm perfectly happy for
them to give different results, because I understand that they are
measuring different things.
Luc Bourhis
>
> >>> More it demands you abandon what you measure with stationary rulers
> >> because it conflicts with theory.
> >
>
> Dennis: According to the R&T explanation of Sagnac is the distance around the
> rim the same CW as CCW?
I have endlessly explain this point. Let's try again.
In the frame of the rotating rim, precisely the frame whose world lines
are parametrized by
(t,x,y,z) = (t, R cos(w t + theta0), R sin(w t + theta0), 0)
in some inertial frame (the lab for example),
(1) an observer moving infinitively slowly from a point A on the rim
back to A will measure with his rulers the same length L whatever is his
direction of motion (co- or counter-rotating).
(2) the length of a light ray propagating from A back to A is different
from L and is different for a co- and a counter-rotating ray.
(3) the length of the trajectory of a particle moving with a constant
speed V wrt the rim from A back to A is different from L and is
different for a co- and counter-rotating particle.
On the contrary you postulate that all these lengths are equal. But then
in case (3) it becomes impossible to explain why two particles sent from
A with the same speed with respect to the rim come back to A at
different times. One has therefore to recognize that this hypothesis is
a prejudice, coming from Galilean mechanics.
You might be interested to know that you share it with giants of modern
science like Landau. Indeed only a particular class of non-inertial
frames, the "rotating" ones, leads to the kind of problems discussed
here, and therefore this prejudice can easily stay hidden even in the
mind of a relativist.
Luc Bourhis
>
> >
> >> Let me repeat the conclusion: Thus, (even for Lorentzian etherists) the
> >> Galilean nature of light is clearly recovered in the experiment--because
> >> there are no relevant deformations of the measuring devices to counteract
> >> this Galilean nature.
> >
> >affected by the ether wind, both for time and length measurement, while a
> >given small section of the rim is not ? This is utterly incoherent.
>
> you is very laborious.
What is laborious is your total lack of scientific rigour, as shown by
your answer to my question. You keep confusing a scientific discussion
with a rhetorical debate and this is really counter-productive.
> Lets define Galilean as the fact that if the actual speed of light is c in
> frame S, then the actual speed of light in S' (where S' is moving at v wrt S)
> is c+v, okay?
This is Galilean physics, indeed.
> Now, what don't you understand about MM?
> It's one frame and the **measured** speed of light was close to isotropic.
> So where did you lose Galilean relativity here?
If there is an Ether wind faster that a few 10 m/s, the Galilean
analysis you have just sketched is ruled out by modern experiments
(Brillet et al, Riis et al, ...). You have then two choices as explained
later in the message of mine you have just answered.
> >Therefore in a Sagnac experiment with neutrons, one has actually particles
> >moving in opposite directions with the same speed with respect to the rim
>
> Dennis:Sigh. If the objects are moving at the same speed wrt the rim, then
> they move around the rim in the same amount of time. That's tautological.
Only because of your prejudices but this is not what is observed
experimentaly.
> >(this can be verified experimentally) and a Galilean analysis is refuted
> >experimentally.
>
> Dennis: Another bizarre confusion.
You have just admitted that a Galilean analysis can not explain the
result I have cited. So instead of hiding your head in the sand you had
better to address this question in a scientific way.
Dennis McCarthy
>>RChan: >You're making the same mistake Selleri made, the one
>>>that R&T corrected in their paper... The whole message of
>>>R&T's paper is that Selleri was mistaken in assuming the
>>>existence of a coherent frame of reference covering the
>>>entire disk...
>>
>>Dennis: Exactly and finally.
>
>mistake as Selleri.
Dennis: You edited out your comment in such a way that it is completely
misleading. That's not the comment I agreed do.
Here's your statement again:
Chan; "R&T correctly explained that this premise is
>false, and that the correct application of the principles of
>special relativity does not lead to an anisotropic ratio of
>light speeds, regardless of the size or speed of the disk.
Chan: Let's see how long your moment of clarity
>lasts.
>
>On 10 Mar 2000 Dennis McCarthy wrote:
>>And since we know ... the two rays take a different amount
>>of time to travel CW and CCW around the rim ...this means
>>the distance is different for the two different directions
>>around the rim--according to the rim observer.
>
Chan: >Gosh, that moment of clarity didn't last long. In one sentence
>you acknowledge that you were erroneously assuming, like Selleri,
>the existence of a coherent frame of reference covering the
>entire disk, and in the next sentence you emphatically re-assert
>the same erroneous assumption.
Dennis: Sigh. What are you talking about? I wrote that R&T's argument is that
length around the perimeter is not the same CW as CCW according to the rim
observer. Are you denying this? Are you saying that the length around the rim
CW and CCW is the same?
>On 10 Mar 2000 Dennis McCarthy wrote:
>>...the belief that the desk your computer is on is longer CCW than
>>CW--according to *you*--who is stationary wrt the desk--seems a
>>little artificial, don't you think?
>
Chan: >No, quite the contrary. I regard significantly accelerating systems
>of reference as a little artificial,especially for evaluating
>physical phenomena
Dennis: That's unfortunate as all human beings on this Earth live in an
accelerating system and conduct length measurements with respect to one
(especially for physical phenomena.) For all other experiments, we trust those
measurements--and it's not a problem.
>On 10 Mar 2000 Dennis McCarthy wrote:
>> That's certainly not what you measure.
>
Chan: >It's not?? You just said it WAS.
Dennis: Huh? Of course I didn't say it was what we measure. How does one
measure (with rulers) the fact that my desk in front of me is longer CCW than
CW?
Chan: >It sounds like you're having
>trouble distinguishing between two different measurements, and this
>difficulty stems from your inability to grasp spacetime as a unified
>four-dimensional manifold.
Dennis: Well, certainly my intelligence is very limited, but why do I need to
grasp "a unified four-dimensional manifold" in order to measure the length of
the perimeter of my desk?
Chan: >
>The slow pacing method of measuring a spatial distance consists of
>a number of disjoint spacelike intervals (the size of your foot)
>paired up sequentially with physically contiguous segments of the
>rim. On the other hand, the lightbeam method of measuring (or
>comparing) spatial distances consists of the spatial project a
>continuous null helical path of light through spacetime
Dennis: Whoooa. I can't see any "null helical path." How do I take my ruler
and measure this thing? See I just want to measure the perimeter of my desk.
You seem to be making it difficult. If you say there are two ways, how do you
measure it your way or the "correct" way?
Chan: With respect to any inertial coordinates we can easily
>do this on the same basis for both beams, but if (for some reason)
>we insist on projecting the light path onto a system of reference
>that is continuously changing its inertial frame in one particular
>direction
Dennis: All systems of reference ever on the planet of Earth have had this
characteristic, yet all scientists measure length the same way.
Wouldn't it be easier to follow a theory that allows such a measuring
scheme--and doesn't have this difficulty?
Chan:(by rotating in that direction), it's hardly surprising
>that this yields unequal spatial projections for the two beams of
>light
Dennis: Oh, so it's "not surprising" that my desk is longer CCW than CW? Hmmm.
You must be more "inuitive" than I. I've just marked my desk off via a ruler,
and as I stare at the markings they seem to read the same amount both CW than
CCW.
What happened? What am I missing?
How do you measure it your way?
You talk about helices that I can't see. How do I measure them with measuring
instruments?
Chan: >You're dissatisfied with the fact that two measurement procedures
>give different results, because you don't see that they are measuring
>different things (apparently because the difference involves the 4th
>dimension, which you seem unable to grasp)
Dennis: I still only know of one "measuring method." I haven't been told about
any other measuring procedure for length other than to take my rulers and mark
off the desk. Your are talking about "null helical paths" that I can't see.
How do you measure this with rulers?
Dennis McCarthy
Dennis McCarthy
>> Lets define Galilean as the fact that if the actual speed of light is c in
>> frame S, then the actual speed of light in S' (where S' is moving at v wrt
>S)
>> is c+v, okay?
>
>This is Galilean physics, indeed.
>
>> Now, what don't you understand about MM?
>> It's one frame and the **measured** speed of light was close to
>isotropic.
>> So where did you lose Galilean relativity here?
>
>analysis you have just sketched is ruled out by modern experiments
>(Brillet et al, Riis et al, ...)
Dennis: Sorry, the most accurate MM experiment (Brillet) point to an ether
velocity greater than that. As I wrote to you and you never responded:
You see, there's a slight difficulty here. BH showed an
isotropy wrt sidereal coordinates to within .13 +/- .22 hz. Yet, for a
non-Lorentz-contraction ether theory that predicts absolutely no
rotational velocity of the ether wrt the Earth's surface--and so a velocity of
light that equals c+/-v--where v is the velocity of the rotation of the earth
at
the latitude of the lab-frame, the prediction for the latitude of the BHX
lab-frame is for a shift of 31 hz (cos 2 theta) where theta is the angle of
their Fabry-Perot with respect to the east.
Interestingly, for BH, while the "experiment has been designed
to be clear in its interpretation and free of suprious effects," nevertheless,
Brillet Hall reported a "persistent spurious'(1) effect of 2 (theta) amplitude
of
17 hz shift (+/- about 35% for the data sent shown) at an 'approximately
constant phase in the laboratory frame' of about -30 degrees +/- 10
degrees...." (2)
None of the data points was within 10hz of isotropy. Although BH did not
provide data of the orientation of their apparatus with respect to the compass
points, the expeirment was not consistent with isotropy--but is
consistent with ether theories that predict no or small ether velocity wrt the
ECI
frame.
References:
Hayden, H. "Is the Velocity of Light Isotropic in the Frame of the Rotating
Earth?" Physics Essays, Vol. 4, no. 3, 1991
The other is from:
Brillet, A. and Hall, J. Phys. Rev. Lett. 42, 549 (1979)
Now, please explain how SR is perfectly consistent with BH. Now to your other
points:
Bourhis: >You have then two choices as explained
>later in the message of mine you have just answered.
Dennis: Those two choices are a contration of the apparatus AND Galilean
relativity.
And slow ether velocity wrt the Earth AND Galilean relativity.
Now, let me repeat my statement: Galilean nature of light is clearly recovered
in the experiment--because there are no relevant deformations of the measuring
devices to counteract this Galilean nature.
Hopefully, we're agreed.
--Dennis
Dennis McCarthy
Dennis McCarthy
particles
>> >moving in opposite directions with the same speed with respect to the rim
>>
>> Dennis:Sigh. If the objects are moving at the same speed wrt the rim, then
>> they move around the rim in the same amount of time. That's tautological.
>
>experimentaly.
Dennis: Sigh. You..yourself... said "one has actually particles moving in
opposite directions with the same speed with respect to the rim."
Now, do you mean distance/time by speed?
Is the rim the same distance CW as CCW?
Then, guess what? If they travel at the same speed wrt the rim, then they move
around the rim in the same time.
That's tautological.
Now, if one wins the race, guess what that means?
It means that that object...moved...faster.
Now, sigh, are we clear here?
Dennis McCarthy
Dennis McCarthy
>
>Dennis McCarthy wrote:
>>
>> >>> More it demands you abandon what you measure with stationary rulers
>> >> because it conflicts with theory.
>> >
>> Bourhis: >No.
>>
>> Dennis: According to the R&T explanation of Sagnac is the distance around
>the
>> rim the same CW as CCW?
>> Is that what you measure with stationary rulers?
>
Dennis: No answer to the question. Please answer it with a yes or no.
According to the R&T explanation of Sagnac is the distance around the rim the
same CW as CCW according to the rim observer?
Bourhis: Let's try again.
>
>In the frame of the rotating rim, precisely the frame whose world lines
>are parametrized by
> (t,x,y,z) = (t, R cos(w t + theta0), R sin(w t + theta0), 0)
>in some inertial frame (the lab for example),
>
>(1) an observer moving infinitively slowly
from a point A on the rim
>back to A will measure with his rulers the same length L whatever is his
>direction of motion (co- or counter-rotating).
>
>(2) the length of a light ray
Dennis: What's the "lenght of a light ray"? How about if I just shoot a short
pulse?
Bourhis: propagating from A back to A is different
>from L and is different for a co- and a counter-rotating ray.
Dennis: How do you know that? I can't see that. According to me the two
pulses move the same distance. This is certainly what I measure.
Are you sure you're not sneaking in some assumptions here which already assume
that the speed of light is c--even though that is what we are trying to
measure--and so assume the path length is different? ;-)
You also said this explanation is also true for all objects moving around the
rim. Are you saying that two mathbox cars moving around the perimeter of my
desk move different path lengths for the two cars?
Bourhis: >(3) the length of the trajectory of a particle moving with a constant
>speed V wrt the rim from A back to A is different from L and is
>different for a co- and counter-rotating particle.
Dennis: Ahhh, so yes you are saying that. So runners around tracks in the
northern hemisphere should run clockwise for faster times, right?
And this should be noticeable for cars going around tracks, correct?
Bourhis: >On the contrary you postulate that all these lengths are equal. But
then
>in case (3) it becomes impossible to explain why two particles sent from
>A with the same speed with respect to the rim come back to A at
>different times.
Dennis: Holy...cow.
They..ain't..moving...at...the...same...speed...wrt...rim...if...they..com
e...back...at..different...times.
Wow.
Bourhis: Indeed only a particular class of non-inertial
>frames, the "rotating" ones, leads to the kind of problems discussed
>here,
Dennis: Actually, the Galilean analysis leads to no problems at all. The only
problem comes when a relativist tries to reconcile what he measures with what
he wants to believe. And at that point relativists throw out what they
measure.
Dennis McCarthy
greyw...@my-deja.com
>
> Chan: >You're dissatisfied with the fact that two measurement
procedures
> >give different results, because you don't see that they are
measuring
> >different things (apparently because the difference involves the 4th
> >dimension, which you seem unable to grasp)
>
> Dennis: I still only know of one "measuring method." I haven't been
told about
> any other measuring procedure for length other than to take my rulers
and mark
> off the desk. Your are talking about "null helical paths" that I
can't see.
> How do you measure this with rulers?
>
Dennis, I think you missed Chan's remark about the fact that you are
measuring two "different things".
This is known as redefining the question. You are asking what is the
distance around a three-dimensional object. This never changes. Chan
is "measuring" a dynamic "time-helix", which is never the same.
The difference is that Chan's helix has no physical reality.
Perhaps if Chan answered the question,
Which four-dimensional time-helix is longer? One based on measuring a
desk clockwise, or one measured counter-clockwise?
--
greywolf42
Dennis McCarthy
>
>>
>> Chan: >You're dissatisfied with the fact that two measurement
>procedures
>> >give different results, because you don't see that they are
>measuring
>> >different things (apparently because the difference involves the 4th
>> >dimension, which you seem unable to grasp)
>>
>> Dennis: I still only know of one "measuring method." I haven't been
>told about
>> any other measuring procedure for length other than to take my rulers
>and mark
>> off the desk. Your are talking about "null helical paths" that I
>can't see.
>> How do you measure this with rulers?
>>
>
>measuring two "different things".
>
>This is known as redefining the question. You are asking what is the
>distance around a three-dimensional object. This never changes. Chan
>is "measuring" a dynamic "time-helix", which is never the same.
>
>The difference is that Chan's helix has no physical reality.
>
Dennis: Right. That's actually my point. The "distance" that is used to
determine the speed for Sagnac in SR is not determined by a ***measurement**
(i.e, no one uses a ruler to determine this) --but by theoretical assumptions
which lead to certain **calculations.**
When measuring the speed of light, relativists actually reject the
**measurement** of the path length by actual real rulers--and instead use their
own **calculations** to determine an unobservable path length. And these
calculations are *based* on SR and so based on the notion that the speed of
light is constant--which is what we are trying to measure.
Since the *measured* pathlength by rulers does not conform to their theory,
they throw out the measurement.
Instead, they use a *calculated* figure for path length which is based on the
very assumption (constant c) that the experiment is designed to test.
Dennis McCarthy
Dennis McCarthy
>
>> point to another (in your frame)--all scientists and engineers measure the
>> distance between the points (according to your frame) and divide by the
>> time of travel. I explained this for a week, showing how you glue rulers
>> around the rim to measure the path. You accepted this incredibly obvious
>> method of distance measurement that all scientists and all engineers use.
>> What happened since then?
>
light rays
>or of particles trajectories rotating along the rim.
Dennis: 1) Can I observe these lengths of light rays or "particle
trajectories"? Or do you just take it on faith that this is what the
trajectories are based on theoretical assumptions (i.e., constancy of c) which
the experiment is supposed to test.
2) You do realize the Sagnac effect occurs for *stationary* rings in
laboratories, right? So you think cars driving around a track in opposite
directions (CW and CCW) travel different distances, correct?
3) Consider:
A) We have a theory which states that some value a/b = K.
B) Now, we are going to conduct an experiment where we are trying to determine
the value of a/b and so test the theory. (Such experiments have been conducted
100's of times.)
C) Now, do you know of any experiment in the history of science in which the
experimenters *reject* the **measured** value of "a" --and instead
**calculate** a *different* value of "a" based exclusively on an *unobservable
assumption* that is based on the belief that (get this)
a/b = K.
I mean, Bourhis I completely agree that the speed of any particular object is
*always constant* as long as we don't use rulers to measure distance--and
instead calculate the value of distance based on the assumption the speed of
the object is constant.
But, tell me the truth: does that not seem to be a tad circular and
disingenuous?
Dennis McCarthy
Dennis McCarthy
point to another (in your frame)--all scientists and engineers measure the
>> distance between the points (according to your frame) and divide by the
>> time of travel. I explained this for a week, showing how you glue rulers
>> around the rim to measure the path. You accepted this incredibly obvious
>> method of distance measurement that all scientists and all engineers use.
>> What happened since then?
>
Bourhis: >This procedure gives the length of the rim but not the length of
light rays
>or of particles trajectories rotating along the rim.
Dennis: Really? I have a laser on a square desk and three mirrors. The laser
is a thin red line that *you can see*! The laser is emitted from southwest
corner hits the mirror on the southeast corner is deflected to the northeast
corner is deflected to the northwest corner and is deflected back to the
mirror. The visible lines of the laser form a square from my lab
perspective--right...along...the perimeter of the table. I have the greatest
engineers and mircometers in the world in the lab. They measure the length of
the square table to be 1 meter a side and 4 total meters.
They measure the actual line of the laser (that they can see!!) and again, with
their stationary micrometers, they measure 4 total meters.
Now, tell me, Bourhis, please, what is the path length of that ray of light
according to my lab partners, the desk and me?
(I'm going to email this to you, because I would really love an answer to this
question.)
Dennis:>> Don't you think it's more reasonable to abandon the theory--not the
>> universally accepted and reasonable measurement method?
>
B:>For the 666th time, please come with an alternative as general and well
>supported by experimental evidences than SR and we will discuss again this
>point.
Dennis; Oh, great. So if I have a theory that reproduces the SR
predictions--but uses standard measurement procedures (i.e, with a ruler--not
with theoretical calcuations) for path length, then that theory should be
preferred?
greyw...@my-deja.com
djm...@aol.com (Dennis McCarthy) wrote:
> Dennis: Right. That's actually my point. The "distance" that is used
to
> determine the speed for Sagnac in SR is not determined by a
***measurement**
> (i.e, no one uses a ruler to determine this) --but by theoretical
assumptions
> which lead to certain **calculations.**
> When measuring the speed of light, relativists actually reject the
> **measurement** of the path length by actual real rulers--and instead
use their
> own **calculations** to determine an unobservable path length. And
these
> calculations are *based* on SR and so based on the notion that the
speed of
> light is constant--which is what we are trying to measure.
> Since the *measured* pathlength by rulers does not conform to
their theory,
> they throw out the measurement.
> Instead, they use a *calculated* figure for path length which is
based on the
> very assumption (constant c) that the experiment is designed to test.
>
True. But they can always claim that their methodology is internally
consistent.
So was Ptolemy.
Mark Samokhvalov
Luc Bourhis пишет в сообщении <38C7D822...@durham.ac.uk> ...
>Mark Samokhvalov wrote:
>>
>> To my knowledge, ALL experiments performed to detect the effect of the
>> Earth's orbital velocity on physical processes, including my own to
detect
>> the anisotropy of electrophysical parameters induced by it, have produced
>> nil results.
>Also to my knowledge. At least, experiments which have given positive
>result have been shown to have systematic effects or their results have
>not been reproduced.
>
>> Together with the existence of star aberration, this could be
>> explained by ether drag by the Earth's gravitational field and verified
by
>> any of the aforementioned experiments on board satellites, or on the
Earth
>> by such experiments sensitive enough to detect the effects of Earth's
>> rotation velocity. Perhaps, such experiments have already been
performed -
>> any information?
>
>So you believe that Ether is dragged not only by the translation of
>Earth around the Sun but also by the rotation of Earth around its axis,
>do you ?
It's not belief, it's what has to be tested. Ether co-rotation is ruled out
by the Earh's rotation Sagnac effect.
Then a purely Galilean Ether might not be ruled out by
>experiments made on Earth surface but with this hypothesis you have
>opened the Pandora box and you have to deal with every sin jumping out
>of it. You need a vortex around each satellite of Saturn, embedded in a
>vortex around Saturn, embedded in a Vortex around the Sun, and so on for
>each planets and comets. What are the prediction for bending of light or
>Shapiro time delay for example ? What about the GPS system ? In order to
>save Ether, you have just created even more problem to solve. This is
>quite typical and this is the reason why the concept has been
>abandonned.
It's there again under the eupheism of "physical vacuum" - the source and
sink for particle - anti-particle pairs. Hence, the obvious problems of its
interaction with conventional matter, and the need for their solution in the
spirit of materialism and causality. The gas vortex ether theory doesn't
appeal to me - I advocate I.Sharov's ether crystal model, in which particles
are regarded as imperfections of the ether crystal lattice. According to it,
the mass-energy relation is an energy transformation of lattice defect
energy into vibrational energy in which the inertial mass of ether particles
associated with the imperfection (mass) remains the same after they are
incorporated into the regular lattice, but the gravitational mass vanishes;
the lattice close to an imperfection is normally softer, hence its phonon =
photon velocity is less, hence, refraction and bending of light. Of Shapiro,
I know nothing.
>
>> >The 3 following objects have different length:
>> >- the trajectory of a co-rotating particle
>> >- the trajectory of a counter-rotating particle
>> >- the rim
>> >if one works in the non-inertial frame whose world lines are defined by
the
>> >following parametric equations in some inertial frame:
>> > x0 = t
>> > x1 = a cos(w t) - b sin(w t)
>> > x2 = a sin(w t) + b cos(w t)
>> > x3 = 0,
>> >with (a^2+b^2)^(1/2) being the radius of the rim and w its rotation
speed.
>> Clearly, a case when sollipsism comes in conflict with reality -
different
>> results obtained by reasoning with no physical cause.
I beg your pardon, sollipsism, or not, this is the solicited answer, Thank
you. And after some thought, I begin to see some physical sence in it that
Dennis, too, could see: the circular route of ligh/particles involves
reflections, and the condition for them need not be the same for both rays,
PROVIDED THERE IS AN INHERENT TANGENTIAL ANISOTROPY ON THE RIM. For an
etherist, the same process must work irrespective of the RF. However, since
c+.-v produces an accurate result, there's no need to consider the
contribution of that process.The GR, on the other hand claims, that such
anisotropy is created by the rays/particles themselves interacting with
what? Right, space-time! So at present, instead of a material ether we have
the duality of "physical vacuum" and "space-time" to account for various
classes of physical processes.
>
>What is a physical cause ?
The action of a material object responsible for the effect.
>
>> SR was originally
>> constructed not as a physical, but as a metric theory - had another
signal
>> carrier (e.g., fast particles) been used, the results would have been
>> different.
>You mean that the length of the trajectories would have been different,
>do you ? You are right but what is funny is that the difference between
>them does not depend on the speeds of the particles as long as they are
>the same in the two opposite directions along the rim.
Mine was a general proposition not restricted to the Sagnac set-up. Get an
idea of it by simply substituting a velocity of some signal carrier for c in
SR.
>
>> Had different signal carriers been used jointly, all ambiguity
>> (=relativity), would have been removed.
>????
The ambiguity = relativity of SR stems simply from the fact that it uses
only one signal carrier, and, hence is unable to establish experimentally
the c(v) dependence. This is made possible by the use of two, or more,
signal carriers.
>
>> Indeed, during the XX-th century triumphs of theoretical physics elated
the
>> intellectual elite aleready influenced by sollipsist philosophy to the
>> extent that they thought they could construct reality.
>
>Modern science *does model* reality. We works with mathematical
>idealisation of the reality and not with the reality itself. This
>process is not really new: it has started with Galileo.
>
>> It the same with
>> quantum physics: all sorts of weird hypotheses have been advanced to
explain
>> the interference of isolated quanta instead of aknowledging the simple
fact
>> of their division and propagation in the form of sub-quantum
oscillations.
>????
This is another story - I needn't have mentioned it.
The effect is proportional to v/c^2 (v is the rim's speed), isn't it?
In rim"s frame, E=m(V+,-v)V^2/2. It is caused by m's dependence on v (rim
speed). In the rim
frame, co- and counter-rotating speeds of equal-energy particles ARE
DIFFERENT, because of particle mass interaction with static ether.
>
>> >What is tremendously interesting however is that one finds the same T
for
>> >this shift between clocks and for the delay between the arrival time of
>> >particles rotating in opposite direction even if a priori there is no
links
>> >between these two configurations.
If one remembers that the same geometry of
>> >spacetime is at work, everything becomes clear and indeed the important
point
>> >is of course that SR gives the correct predictions for all these
effects. And
>> >Ether theories ?
>>
>> No space-time needed. Suffice it that both effects are described by small
>> terms quadratic in V. Integration over travel time produces the result.
>
>Please show the details. For SR/GR you have them in the references given
>by me and others in this thread.
It's simple tedious maths based on experimental values of m(V) and T(V).
Relativity, to its credit, predicts these dependances, so do alternative
theories. I have also obtained some of them for the ether crystal model
using Newtonian physics and symmetry and dimensionality. I long for a clear
yes - no experiment, and wouldn't waste my time on calculations when
qualitative results are clear. That's how one makes them. For the clocks,
the physdical cause of "time dilation" is the effect of ether wind on the
frequency standard, hence: T = T(o)(1 - (V+,-v)^2/2c^2), where V is the
translation, and v - the rim's velocities. So, for the difference we obtain:
difT = 2Lv/c^2, where L= TV is the rim's length. For particles, one has to
solve E=m(o)(1+(V+,-v)^2/2c^2)V^2/2. So don't insist on remarkable SR
results.
>
>> >I do not understand : do you say the the equivalence principle can be
>> >believed or that it is ruled out ? I do not know any experimental data
>> >supporting the latter.
>> >
>> I mean, it doesn't work, because the clocks on satellites at different
>> altitudes tick differently.
>
>Why does this contradict the equivalence principle ?
Is the situation aboard a satellite any different from that in a falling
lift cabin Einstein cited to illustrate the principle? A falling cabin is
equivalent to an inertial RF. All inertrial frames are equivalent, hence all
falling cabins and satellites are. Observers aboard satellites in different
orbits synchronise their clocks. Time passes, they check them in the same
position and find they went astray. Why, if all the satellites were
equivalent?
Tom Roberts
> You are asking what is the
> distance around a three-dimensional object. This never changes.
Only if one is willing to speak so loosely that the important
distinctions are lost, as both you and Dennis repeatedly do.
The real question is: what is measured? and it's quite clear that
distance _MEASURED_ around a 3-d object can vary, depending upon
precisely how one performs the measurement. If, for instance, the
object is moving inertially wrt you, then you will measure two of
its sides to be length contracted; if it is at rest wrt you then
there will be no such contractions; if the object is moving non-
inertially then you can make several different measurements and
obtain several different answers, yet all are reasonable ways
to measure such a "distance around".
In SR you measure the distance between two points on an object
by laying a ruler down at rest in YOUR rest frame and marking
the positions of the two points in question SIMULTANEOUSLY using
clocks at rest in YOUR rest frame. The problem is, for a rotating
object it is impossible to do this all the way around.
As long as you and Dennis keep making ambiguous remarks containing
unintended puns on the words you use, you will keep making false
statements about how an anlysis of this is performed in SR.
> Which four-dimensional time-helix is longer? One based on measuring a
> desk clockwise, or one measured counter-clockwise?
As I said above, this depends upon how you measure it and how the
desk is moving (both wrt you and wrt some inertial frame). Ask a
wishy-washy question and you get a wishy-washy answer.
Tom Roberts tjro...@lucent.com
Tom Roberts
> If in every 10 miles of a trip from NY to Albany,
> you averaged 50 MPH--yet your average velocity for the whole trip was 70
> MPH--now, that's a little strange, wouldn't you say?
It depends upon how those different measurements are made. You ignore
the essential difference that in the case of a rotating rim the
local measurements are each made in a different inertial frame.
There is no requirement whatsoever that an average of speeds
measured in different inertial frames should be equal to some
global-average speed measured in a non-inertial frame.
> The average velocity of light for each leg is c, yet the average for the
> whole leg is c+v? Are you kidding?
You got it wrong: the _LOCAL_ velocity of light for each leg is c.
You are not acknowledging the hidden pun in your word "average" --
this is not the usual average performed in a single frame, this is
an "average" over measurements performed in different frames, and
there is no requirement that they behave as an arithmetic average
would, as you claim.
Example using Galilean relativity: Consider a trip between
two earthbound points 30 miles apart along a straight road
headed northwards. During the first 10 miles you drive 50
MPH in a frame moving 25 MPH southbound wrt the earth,
during the second 10 miles you drive 50 MPH in a frame at
rest wrt the earth, and during the third 10 miles you drive
50 MPH in a frame moving 25 MPH northbound wrt the earth.
And yet the average speed for the trip is not 50 MPH in the
earth frame. This is a silly and artificial example, but it
shows that combining local speeds from different frames
does not work as Dennis supposes.
> Dennis: Um, first-year-algebra meet Roberts. Roberts, first year algebra.
> If an object moves the same average local speed for all segments, of course,
> this equals the average global speed as well.
See my simple example above for a counterexample. You are ignoring
the fact that the local speeds are measured in different frames.
This takes more than "first year algebra", this requires an
analysis of the physical situation.
> [about my circle example]
> the local lengths of the circle do add up to the total length of
> the circle. The distance from the starting point does not equal the total
> length of the circle because the segments were angled back so they returned to
> the same spot.
And similar remarks apply to your attempt to "average" the locally-
measured speeds into the global average speed. The local ones were
"angled back" in just the same manner you describe, and this means
they are measured in different frames, and do not combine as you
claim.
Tom Roberts tjro...@lucent.com
z@z
http://www.deja.com/=dnc/getdoc.xp?AN=389605943
: The outline of his argument is:
: 1. using a single clock measuring the speed of light all the way around a rotating
: circular path, the speed is measured to be c+v and c-v in the two directions.
: 2. because of the circular symmetry, the same speed would be measured over any
: small region of the rotating circular path.
: 3. "a set of platforms with growing radius, but all with the same peripheral
: velocity, locally approaches better and better an inertial frame" [p 77]. They
: all measure c+v and c-v for the local speed of light, independent of radius.
: 4. but SR predicts the speed of light for an inertial frame is c.
: 5. 3 and 4 above show a discontinuity in the theory which does not make sense
: physically -- the limit of infinite radius (zero acceleration) for the locally-
: measured speed of light should be the same as the speed in an inertial frame.
: 6. thus, SR is inconsistent.
:
: The basic error in this argument is in step 3 -- for the situation described, as
: the radius increases the rotating system does not locally approach an inertial
: _FRAME_. The emphasis on the last word is important -- the system does indeed
: approach inertial motion, but not an inertial frame as defined in SR. Remember,
: please, that an inertial frame consists of a set of inertially-moving rulers and
: synchronized clocks all at rest wrt each other. The rotating system used by
: Selleri has clocks synchronized differently from those in an inertial frame, and
: this different synchronization remains in the infinite-radius (zero acceleration)
: limit.
:
: If one imagines placing clocks all the way around the circular light path on the
: rotating platform, Selleri's description makes them all be synchronized in the
: inertial frame in which the center is at rest. This is natural and normal, as it
: is the only way to obtain a self-consistent synchronization of multiple clocks
: all the way around the circle. His equation (1) reflects this, and is also clear
: from his description at the bottom of page 78: "if the platform is set in motion
: in a regular way, no difference between clocks on its rim can ever arise." Note
: that at least two clocks on the platform are required to measure the speed of
: light over a small region of its rim (i.e. locally), so the method of
: synchronization is important. Selleri does it in the only way possible which is
: consistent all the way around, and then takes the limit as radius -> infinity
: (i.e. at each step of increasing radius the clocks are resynchronized).
:
: Thus, at every step of increasing radius, the clocks remain synchronized in the
: inertial frame in which the center is at rest. In the limit, one has a locally-
: inertial system moving with velocity V wrt the original inertial frame, BUT WITH
: CLOCKS SYNCHRONIZED IN THAT ORIGINAL INERTIAL FRAME. For such a situation, using
: clocks synchronized that way, the measured "speed of light" will be c+v and c-v.
: Hence the limit in figure 1 exists, and is consistent with the rotating system
: for large radius (and even for small radius).
:
: But this is NOT the way an inertial frame is used to make measurements in SR --
: the clocks must be synchronized in the frame used to make the measurement, not
: in some other inertial frame. This is a favorite error of students in Physics
: 201, and is universally recognized as an error (mixing up measurements in two
: different frames, or using improperly-synchronized clocks to measure a "speed").
:
: Thus the discontinuity described by Selleri is merely an artifact of the way he
: set up his gedanken experiment, and does not show any inconsistency in the theory
: at all.
An excellent text because of its clarity and conciseness!
Nevertheless its conclusion is based on the wrong assumption that SR does
not fully determine the time coordiate and that different synchronizations
are possible for one single system having or approaching inertial motion.
Let us assume we have a 1000 light year (LY) long tube with a diameter
of e.g. 10 m. If it moves at 0.886 c, its length is contracted to 500 LY.
So we can create a ring with radius of 500 LY / 2pi rotating at 0.886 c.
I'm sure a lot of strange consequences and contradictions will result from
physical experiments within the ring-shaped tube.
One must not forget that SR velocity addition requires the SR simultaneity
concept. The way we synchronize clocks however, is irrelevant.
Wolfgang Gottfried G.
My version of a Sagnac paradox:
http://members.lol.li/twostone/E/refutationSR.html
Ein Sagnac-Paradoxon von mir (ausführlicher als die englische Fassung):
http://members.lol.li/twostone/ltg_mm.html
Robert Chan
>Are you saying that the length around the rim CW and CCW
>is the same?
You ask about the "length around the rim", apparently not
understanding the ambiguity in your question. Notice that the
length of a year is about 365 days, and the "length around
the rim" might be 30 seconds or 2 hours or 1 nanosecond, etc.,
depending on how fast you are going, how fast the rim is
spinning, in which direction it is spinning, and so on. But
of course none of these is the answer you have in mind, because
these are all temporal lengths, whereas (I assume) you're asking
for the SPATIAL "length around the rim".
However, even with the understanding that you're interested
in SPATIAL length, the question is still ambiguous. In general,
the definition of the spatial length of an object (such as
the perimeter of the rim) is the absolute length of a locus of
inertially simultaneous points of that object, so we need to
establish a slice of "inertial simultaneity" over the entire
rim. If we use inertial coordinates this is easy, but if we
use non-inertial coordinates (such as those in which the rotating
disk is stationary), we will find that no surface of inertial
simultaneity coincides with our surfaces of constant time
parameter. This is essentially the *defintion* of non-inertial
coordinates. So, we will obviously be unable to define a
coherent locus of inertial simultaneity over the whole disk
as a surface of constant time parameter when working with non-
inertial coordinates.
Nevertheless, we can (if we wish) throw inertia to the wind, and
simply define non-inertial simultaneity for any arbitrary system
of coordinate as surfaces of constant temporal parameter. However,
there are obviously many different ways of doing this, resulting in
different values for all spatial lengths (as well as all temporal
lengths). This shouldn't be surprising, because the decomposition
of spacetime into separate spatial and temporal components is not
unique, i.e., there are mulitple equally self-consistent
decompositions.
One particular method is what you call the "naive SR approach",
and the consequences of this approach are puzzling to you, so
let me describe this in detail, and explain why there's nothing
mysterious or paradoxical about it. Let's first establish
inertial cylindrical coordinates in 2+1 spacetime, using polar
coordinates (r,q) for the space (where q is the angular coordinate),
and t for time. The metric in terms of these inertial coordinates
is
(dtau)^2 = (dt)^2 - (dr)^2 - r^2 (dq)^2
and for any fixed time t the purely spatial (s) metric is
(ds)^2 = (dr)^2 + r^2 (dq)^2
So, to find the "length" of any spacelike curve, such as the
perimeter of a spinning disk if radius r_d centered at the
origin, we simply integrate ds over this curve at the fixed
value of t. For a circular disk, r = r_d is constant, so
dr=0, and the spatial metric is simply ds = R dq, which we
integrate from theta = 0 to 2pi to give the length 2pi r_d.
Okay, now let's look at this situation in terms of a system of
coordinates in which the spinning disk is stationary, i.e., such
that a fixed point anywhere on the disk maintains constant spatial
coordinates for all values of the temporal coordinate. Taking
the most naive and simplistic approach, let's define the new
coordinates T,R,Q by the relations
T = t R = r Q = q + w t
where w is a constant, denoting the angular speed of these
coordinates with respect to the inertial t,r,q coordinates.
We also have the differentials
dT = dt dR = dr dQ = dq + w dt
Substituting these expressions into the metric equation gives
(dtau)^2 = [1-(Rw)^2](dT)^2 - (dR)^2 + 2wR^2 (dT)(dQ) - R^2 (dQ)^2
According to these coordinates, a spatial (S) length must be given
by integrating the absolute spacelike differential using the metric
along some constant-T surface, i.e., with dT=0, where the metric is
(dS)^2 = (dR)^2 + R^2 (dQ)^2
Again for the perimeter of the disk we get 2pi R_d = 2pi r_d. Notice
that our constant-T surfaces are also constant-t surfaces, so this
perimeter length agrees with our previous result. Also, you'll be
happy to see that it doesn't matter which direction we integrate
around the perimeter.
Incidentally, letting v = R_d w denote the velocity of the rim
with respect to the original inertial coordinates, the full space-
time metric for the rim (R = R_d) in terms of the rotating
coordinates is
(dtau)^2 = [1-v^2](dT)^2 + 2vR_d (dT)(dQ) - (R_d)^2 (dQ)^2
For a point fixed on the rim we have dQ = 0, and so
(dtau)^2 = [1-v^2](dT)^2
which confirms that the lapse of proper time for a point fixed on
the rim of the rotating disk is sqrt(1-v^2) times the lapse of T
(and therefore of t).
Okay, now let's shoot some light beams around the perimeter in
opposite directions and see what happens. For lightlike paths we
have dtau=0, so the path of light must satisfy
[1-v^2](dT)^2 = (R_d)^2 (dQ)^2 - 2vR_d (dT)(dQ)
The purely spatial component is dS = R_d dQ, so we can make
this substitution and divide both sides by (dT)^2 to give
[1-v^2] = [dS/dT]^2 - 2vR_d [dQ/dT]
The quantity dS/dT can be defined as the "speed of light" with
respect to these rotating non-inertial coordinates. Also, from
the definitions we have
dQ/dT = dq/dt + w
where dq/dt is the angular velocity of the light at radius R_d
with respect to the inertial coordinates, so it equals +-1/R_d
(noting that c=1 in our units), with the sign depending on whether
the light is clockwise or counter-clockwise. Substituting into
the previous expression gives
[dS/dT]^2 = 2vR_d [w +- 1/R_d] + [1-v^2]
= 1 +- 2v + v^2
= (1 +- v)^2
Letting C = dS/dT denote the speed of light with respect to these
rotating non-inertial coordinates, we therefore have C = 1 +- v,
where again the sign depends on the direction of the light relative
to the direction of rotation of the disk.
Now, does this simplistic analysis lead to some kind of paradox?
Well, it indicates that the non-inertial "speed of light" with
respect to these rotating coordinates is not equal to 1, and in
fact the ratio of the speeds in the two directions is (1+v)/(1-v).
Of course, this doesn't conflict with special relativity because
these are not inertial coordinates, due to their rotation... but
wait! What if we increase R_d and decrease w in proportion so
that the rim speed v remains constant? The above formulas still
apply, for arbitrarily large R_d and small angular speed w, and
yet the speed ratio remains the same, (1+v)/(1-v). Doesn't this
conflict with special relativity in the limit as the radius goes
to infinity and the angular speed of the rim goes to zero?
Of course not. For one thing, it's easy to see that if t1 and t2
denote the travel times for light pulses circling the disk in
opposite directions, as measured by a clock at a fixed point on
the rim, so that t2/t1 = (1+v)/(1-v), then we have
t2/t1 - 1 = theta/pi
where theta is the angular travel of the disk during the transit
of light. In other words, the observed ratio of travel times around
the rim always differs from 1 by an amount proportional to the
angular travel of the disk during the transit of light, so the net
acceleration (change of velocity) of the rim observer during the
measurement remains in constant proportion to the measured
anisotropy of the transit times. But wait...
Even without waiting around for the light rays to circle the disk
and report their anisotropy, don't the above formulas imply that
the speeds of light in the two directions are in the ratio of
(1+v)/(1-v) instantaneously with respect to our rotating
coordinates, and don't the rotating coordinates approach being
inertial coordinates as R_d increases while holding v constant?
Well, yes and no. Both sets of coordinates use the same time
t = T, but they use different space coordinates, s and S. For
the perimeter of the disk we have
dS/ds = (R_d dQ)/(r_d dq)
= [dq + w dt] / dq
= 1 + w (dt/dq)
= 1 + w/W
where W = dq/dt. The important thing to notice here is that the
ratio dS/ds along a given path depends on the angular speed W
of the path. Recall that for a signal travelling at c=1 (with
respect to the inertial coordinates) around the perimeter we
have W = +-1/r_d, and so
dS/ds = 1 +- v
This is consistent with the velocity ratio
[dS+/dT] / [dS-/dT] = [dS+/ds] / [dS-/ds] = (1+v)/(1-v)
Now, if you haven't been paying attention, you might think this
conflicts with something we found earlier, because we see that the
"spatial distances" around the perimeter are different in the two
directions, whereas we saw earlier that "the spatial distance" was
independent of the direction in which we integrated around the
perimeter, even in the rotating coordinate system. So what gives?
Well, I already noted the answer above. The ratio dS/ds along
a given path depends on the speed of the path. We have
dS/ds = 1 + w/W, and for the perimeter of the disk with rim
speed v and for a path with speed +-V, this gives
dS/ds = 1 +- v/V
If the path is lightlike, we have V=1 and so dS/ds = 1+-v, whereas
when we considered the purely spatial distance around the perimeter
we took the "instantaneous" distance, i.e., we took a spacelike path
with V = infinity, in which case dS/ds = 1 in both directions.
This explains quantitatively what we mean when we say that we are
measuring different things, depending on what spacetime path is
having it's "spatial length" evaluated. Just as the temporal length
of a path around the rim depends on the speed of the path, so too
does the spatial length.
By the way, notice that if we integrate the spatial component of a
path whose velocity V (relative to the original inertial coordinates)
is the same as the rim speed itself, so that v=V, then obviously we
will never move with respect to the disk in one direction, so dS=0
and therefore dS/ds=0, whereas in the other direction we have
dS/ds=2. Similarly if V=0 we will never move relative to the
original coordinates, i.e., ds=0 and therefore dS/ds is infinite
along such a path.
Robert Chan
>perimeter is not the same CW as CCW according to the rim
>observer. Are you denying this?
Denying that you wrote that this is R&T's argument? Or denying
that this is R&T's argument? Or denying this argument?
May I just say, as an aside, that over the course of our
brief discussion I've noticed that you habitually express
yourself in elaborately circuitous and multiply ambiguous
ways, almost as if you were striving to maximize the potential
for misinterpretation and confusion. I'm not suggesting that
you do it on purpose. It's probably just the way your mind
works (and I use the words "mind" and "works" loosely).
On 10 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>>Chan: I regard significantly accelerating systems of reference
>>as a little artificial, especially for evaluating physical
>>phenomena...
>
>That's unfortunate as all human beings on this Earth live
>in an accelerating system and conduct length measurements with
>respect to one...
You might want to consider shock aversion therapy to get over
this. Every time someone points out that SIGNIFICANTLY acceletating
systems of reference are generally inconvenient, and you hear
yourself beginning to spout moronic drivel about there being no
such thing as inertial coordinates you should get a little
electric shock, and/or be required to write on a blackboard
100 times
"I, Dennis, will NEVER EVER again spout moronic drivel
about how all systems of reference are imperfectly inertial,
since it has been explained to me [increment n] times that
the real-world notion of inertial coordinates signifies
coordinates sufficiently close to inertial such that the
non-inertial effects are negligible for the purposes of
the observations in question."
[snip remainder of Dennis' characteristicly stupid gibbering.]
Dennis McCarthy
>greyw...@my-deja.com wrote:
>> You are asking what is the
>> distance around a three-dimensional object. This never changes.
>
>distinctions are lost, as both you and Dennis repeatedly do.
>
:>The real question is: what is measured? and it's quite clear that
>distance _MEASURED_ around a 3-d object can vary, depending upon
>precisely how one performs the measurement. If, for instance, the
>object is moving inertially wrt you,
Dennis: My desk in front of me is not moving at all. Sagnac effect occurs for
light moving around it.
Roberts: then you will measure two of
>its sides to be length contracted; if it is at rest wrt you then
>there will be no such contractions; if the object is moving non-
>inertially
Dennis: Again, not moving at all.
Roberts: >In SR you measure the distance between two points on an object
>by laying a ruler down at rest in YOUR rest frame and marking
>the positions of the two points in question SIMULTANEOUSLY using
>clocks at rest in YOUR rest frame.
Dennis: My desk isn't moving at all. I could use stationary clocks as well
(though I'd love to see citation for using clocks like this in a length
measurement method by any scientists in the history of scientific
experimentation.)
Roberts: The problem is, for a rotating
>object it is impossible to do this all the way around.
Dennis: What are you talking about? It's not even difficult. You do understand
the Sagnac effect occurs for *stationary* "square-rings" in Earth labs
correct? Like the perimeter of my desk?
All engineers, all scientists, and all architects have been measuring length
the exact same way for centuries. It's not even remotely difficult.
Unfortunately, relativists don't like the results here--so they abandon this
obvious procedure.
Roberts: >As long as you and Dennis keep making ambiguous remarks
Dennis: Speaking of "ambiguous" and "loose" remarks, perhaps you can explain
the seeming contradictions below?
Roberts (one day): "In these coordinates the _average_ speed of light
_going_all_the_way_around_the_ring_ is different for the two directions, but
the distance is the same for both rays.
Again there is no mystery -- the light rays travel the same distance at
different average speeds and therefore accumulate
a phase difference."
Roberts (the next day): ">One can take the sum of the rulers laid around the
rotating rim and divide it by the time taken for a light pulse to
circumnavigate the
>rim (measured on a single clock).
But as R&T showed, this is not really "distance"/"time", this is really
"distance plus an admixture of time"/"time", and
calling it "speed" is really a misnomer."
D: See how one day, according to you, you can use stationary rulers divide by
time
and call it "speed"--and the next day you suddenly realize you can't really
trust those darn stationary rulers--and so "calling it "speed' is really a
misnomer." Which time were you
"speaking loosely"?
Dennis McCarthy
Dennis McCarthy
>On 10 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>>Are you saying that the length around the rim CW and CCW
>>is the same?
>
Dennis: No body else on the planet--no engineers, architects, scientists--
*ever* has found such a question ambiguous. The ambiguities and problems are
all part of relativity theory--not in well-known, centuries old, tried and
true, universal methods of measuring length.
Chan; Notice that the
>length of a year is about 365 days, and the "length around
>the rim" might be 30 seconds or 2 hours or 1 nanosecond, etc.,
>depending on how fast you are going,
Dennis: Only a relativist could possibly think the "length of a rim" is 30
seconds.
Chan: how fast the rim is
>spinning, in which direction it is spinning, and so on. But
>of course none of these is the answer you have in mind, because
>these are all temporal lengths, whereas (I assume) you're asking
>for the SPATIAL "length around the rim".
Dennis: Anyone not an idiot knows that.
Chan: >However, even with the understanding that you're interested
Dennis: The ether method has no such problems, gives the same explanation for
sound Sagnac, allows you to trust your rulers, doesn't give different results,
doesn't need any unobseved lengths of paths, and takes 3 lines of algebra.
Dennis McCarthy
Dennis McCarthy
>>perimeter is not the same CW as CCW according to the rim
>>observer. Are you denying this?
>
>that this is R&T's argument? Or denying this argument?
>
>May I just say, as an aside, that over the course of our
>brief discussion I've noticed that you habitually express
>yourself in elaborately circuitous and multiply ambiguous
>ways, almost as if you were striving to maximize the potential
>for misinterpretation and confusion. I'm not suggesting that
>you do it on purpose. It's probably just the way your mind
>works (and I use the words "mind" and "works" loosely).
Dennis: Hmm. You were also confused by what I meant by the "length of the
rim"--saying you thought it could be 30 seconds. If you were really that
confused couldn't you have answered all three questions? I'll try to be more
clear.
Do you deny that R&T's argument is that the length (that's "spatial distance"
to relativists) around the perimeter (of the rim of the table in the Sagnac
experiment) is not the same CW (that's clockwise) as CCW (that's
counter-clockwise) according to the rim observer (that means according the
coordinate syster of an observer who remains stationary wrt the rim. And wrt
means "with respect to.")?
>
>On 10 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>>>Chan: I regard significantly accelerating systems of reference
>>>as a little artificial, especially for evaluating physical
>>>phenomena...
>>
D:>>That's unfortunate as all human beings on this Earth live
>>in an accelerating system and conduct length measurements with
>>respect to one...
>
Chan:>You might want to consider shock aversion therapy to get over
>this. Every time someone points out that SIGNIFICANTLY acceletating
>systems of reference are generally inconvenient,
Dennis: Well, there are Sagnac ring interferometers that remain stationary with
respect to the earth-based laboratory. If you don't think that the surface of
the Earth is a "SIGNIFICANTLY acceletating systems of reference," then I assume
you agree one can one just measure the path length of the ray of light in this
experiment with rulers that are stationary to the lab frame?
(If you find this question ambiguous let me know and I'll restate it.)
Chan: and you hear
>yourself beginning to spout moronic drivel about there being no
>such thing as inertial coordinates you should get a little
>electric shock, and/or be required to write on a blackboard
>100 times
>
> "I, Dennis, will NEVER EVER again spout moronic drivel
> about how all systems of reference are imperfectly inertial,
> since it has been explained to me [increment n] times that
> the real-world notion of inertial coordinates signifies
> coordinates sufficiently close to inertial such that the
> non-inertial effects are negligible for the purposes of
> the observations in question."
Dennis: So Earth lab frames signify "
coordinates sufficiently close to inertial such that the non-inertial effects
are negligible"? Again, if you don't understand the question, I'll restate.
But I have a hunch you'll just ignore it.
>[snip remainder of Dennis' characteristicly stupid gibbering.]
>
>
Dennis McCarthy
Robert Chan
>Chan: You ask about the "length around the rim", apparently not
>>understanding the ambiguity in your question.
>
>Dennis: No body else on the planet--no engineers, architects,
>scientists-- *ever* has found such a question ambiguous.
False. The ambiguities of such questions involving space and time
have been known for thousands of years. Of course, I'm referring
to intelligent and thoughtful people. I would acknowledge that
people like yourself have never detected the ambiguities in this
and many other aspects of existence. That's why life is so much
simpler for dim-witted people. Enjoy.
On 11 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>Dennis: The ether method has no such problems...
No problems for the relativistic treatment of the Sagnac effect
were presented in that post. The post explained in detail the
fallacies of numerous objections to the relativistic point of
view. The fact that there are so many fallacious objections
is just a testament to the bottomless stupidity and desperation
of crackpots like Mr. McCarthy.
On 11 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>Dennis: The ether method ... gives the same explanation for
>sound Sagnac, allows you to trust your rulers, doesn't give
>different results, doesn't need any unobseved lengths
>of paths, and takes 3 lines of algebra.
The naive ether method that McCarthy espouses is logically
incoherent and is based on principles that are incompatible
with many other phenomena, and gives results that work for
the Sagnac effect only because the Sagnac effect is a non-
relativistic phenomena. Sspecial relativity gives the correct
explanation for "sound Sagnac" (even in supersonic flow,
unlike the "ether method"), allows you to trust your rules
AND your clocks (unlike the "ether method"), doesn't give
inconsistent results (unlike the "ether method"), doesn't
rely on unobserveable lengths and time (unlike the "ether
method"), and takes 3 lines of algebra.
Robert Chan
>distance"... around the perimeter (of the rim of the
>table in the Sagnac experiment) is not the same CW as
>CCW according to the rim observer?
Tartaglia says that the spatial length of the perimeter, as
YOU are defining spatial length, is the same in both directions.
(Of course, this is also what I've been telling you.) So yes,
I deny that R&T's "argument" is what you described above.
On 11 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>Well, there are Sagnac ring interferometers that remain
>stationary with respect to the earth-based laboratory.
>If you don't think that the surface of the Earth is a
>"SIGNIFICANTLY acceletating systems of reference," then
>I assume you agree one can one just measure the path length
>of the ray of light in this experiment with rulers that are
>stationary to the lab frame?
You assume wrong. I really find your stupidity hard to believe.
Are you really unable to grasp that "significance" is dependent
on the context? Are you really unable to grasp that the non-
inertialness of the Earth's surface is significant for some
purposes but not for others? Is a difference of 1 inch significant?
IT is if we are measuring someone's height, but it isn't if we are
measuring the distance to Alpha Centuari. The significance of
a given about of acceleration depends on the duration and extent
of the measurement of interest, and the order of magnitude of
the effect being measured, which will be consistent with the
precision of the instruments being used. How many hundreds of
times has this been explained to you? Your inability to absorb
this must be due to the fact that, like all real scientific concepts,
it requires an ability to quantitatively assess the relative
magnitudes of various effects, and you are completely unable to
do this, being limited solely to vague qualitative verbal mumblings
about how things ought to work.
C.J. Luke
>Extract from an article of Tom Roberts (1998/09/09) on the "Selleri paradox":
> http://www.deja.com/=dnc/getdoc.xp?AN=389605943
>
>: The outline of his argument is:
>: 1. using a single clock measuring the speed of light all the way around a rotating
>: circular path, the speed is measured to be c+v and c-v in the two directions.
>: 2. because of the circular symmetry, the same speed would be measured over any
>: small region of the rotating circular path.
>: 3. "a set of platforms with growing radius, but all with the same peripheral
>: velocity, locally approaches better and better an inertial frame" [p 77]. They
>: all measure c+v and c-v for the local speed of light, independent of radius.
>: 4. but SR predicts the speed of light for an inertial frame is c.
This is not a prediction of SR, it is a stipulation.
I have not seen this argument used before but here goes....
If in fact (light/photons) have momentum, then the light is under
constant 'angular acceleration' in this test. If that is true, we are
no longer talking about uniform rectilinear motion and SR does not
apply. That would seem to let SR 'off the hook' so to speak.
>:5. 3 and 4 above show a discontinuity in the theory which does not make sense
>: physically -- the limit of infinite radius (zero acceleration) for the locally-
>: measured speed of light should be the same as the speed in an inertial frame.
>: 6. thus, SR is inconsistent.
This 'inconsistancy' seems more like a problem with math...infinite
radius...is mental construct, not a real thing. I have the same
problem with the discussion of 'singularities'.
"The lack of reason is overcome by the passion of belief"
< c...@totcon.com >
Dennis McCarthy
>>>understanding the ambiguity in your question.
>>
>>Dennis: No body else on the planet--no engineers, architects,
>>scientists-- *ever* has found such a question ambiguous.
>
>have been known for thousands of years.
Dennis: Great. Now, please give me references to anyone pre-1880 who argued
that the length (that's, um, spatial distance) around a perimeter of a disk or
field is "ambiguous" in the way you mean.
Chan: Of course, I'm referring
>to intelligent and thoughtful people.
Dennis: Now, it would be nice if you could refer to quoted people.
Chan: I would acknowledge that
>people like yourself have never detected the ambiguities in this
>and many other aspects of existence. That's why life is so much
>simpler for dim-witted people. Enjoy.
>
>On 11 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>>Dennis: The ether method has no such problems...
>
Chan: >No problems for the relativistic treatment of the Sagnac effect
>were presented in that post.
Dennis: Well, I'll rephrase that to the fact that the ether method has no such
"ambiguities" which have even caused many relativists to misinterpret the
Sagnac effect.
Etherist don't have to abandon their rulers--and just come up with one
measured value for the distance around the rim.
Chan: The post explained in detail the
>fallacies of numerous objections to the relativistic point of
>view. The fact that there are so many fallacious objections
>is just a testament to the bottomless stupidity and desperation
>of crackpots like Mr. McCarthy.
Dennis: To quote another: Can I use that in my sig file?
>On 11 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>>Dennis: The ether method ... gives the same explanation for
>>sound Sagnac, allows you to trust your rulers, doesn't give
>>different results, doesn't need any unobseved lengths
>>of paths, and takes 3 lines of algebra.
>
Chan: The naive ether method that McCarthy espouses is logically
>incoherent
Dennis: References?
Chan: and is based on principles that are incompatible
>with many other phenomena,
Dennis: Refernences?
Chan: and gives results that work for
>the Sagnac effect only because the Sagnac effect is a non-
>relativistic phenomena. Sspecial relativity gives the correct
>explanation for "sound Sagnac" (even in supersonic flow,
>unlike the "ether method"),
Dennis: Huh?
Chan: allows you to trust your rules
>AND your clocks (unlike the "ether method"),
Dennis: Oh, so the speed of light going around my desk is anisotropic wrt
me--as this is what my clocks and rulers measure, right?
Dennis McCarthy
Dennis McCarthy
>
>
>Dennis McCarthy wrote:
>> If in every 10 miles of a trip from NY to Albany,
>> you averaged 50 MPH--yet your average velocity for the whole trip was 70
>> MPH--now, that's a little strange, wouldn't you say?
>
Dennis: LOL. Oh, I see.... Ether theory doesn't have this problem, you see--and
gives unambiguous answers for the above question which happen to concide with
first year algebra--and the well known measurement procedures that everyone on
the planet uses.
Roberts: You ignore
>the essential difference that in the case of a rotating rim the
>local measurements are each made in a different inertial frame.
Dennis: That's an "essential difference" in SR theory--which complicates
matters and needs unobserved helices to straighten things out.
There's no such problem in ether theory.
R: >There is no requirement whatsoever that an average of speeds
>measured in different inertial frames should be equal to some
>global-average speed measured in a non-inertial frame.
Dennis: Ether theory, however, remains consistent with basic arithematic
assumptions.
>> The average velocity of light for each leg is c, yet the average for the
>> whole leg is c+v? Are you kidding?
>
Roberts: >You got it wrong: the _LOCAL_ velocity of light for each leg is c.
Dennis: All measured velocities are averages. Even for short distances.
Roberts:
> Example using Galilean relativity: Consider a trip between
> two earthbound points 30 miles apart along a straight road
> headed northwards. During the first 10 miles you drive 50
> MPH in a frame moving 25 MPH southbound wrt the earth,
(Snip)
Dennis:My statement with regard to the car (or Sagnac) all assumes measurements
according to the same frame. Obviously.
Do you really feel such quibbles are honorable?
>> Dennis: Um, first-year-algebra meet Roberts. Roberts, first year algebra.
>> If an object moves the same average local speed for all segments, of
>course,
>> this equals the average global speed as well.
>
Roberts: >See my simple example above for a counterexample.
Dennis: In an example that shows the extent to which you will sink, your
counterexample bizarrely refers to different frames. I'm obviously assuming
the same frame for this example--and with Sagnac. I forgot I was dealing with
someone who would quibble to such an eye-widening degrees.
I'll repeat my statement:
If in every 10 miles of a trip from NY to Albany, you averaged 50 MPH wrt the
road--yet your average velocity for the whole trip was 70 MPH wrt the
road--now, that's a little strange, wouldn't you say?
Dennis McCarthy
Dennis McCarthy
>>distance"... around the perimeter (of the rim of the
>>table in the Sagnac experiment) is not the same CW as
>>CCW according to the rim observer?
>
>YOU are defining spatial length, is the same in both directions.
>(Of course, this is also what I've been telling you.) So yes,
>I deny that R&T's "argument" is what you described above.
Dennis: In the quesiotn, I'm obviously referring to the SR definition of
"spatial length"--as that is what is determined by R&T. So I'll restate it for
you:
Do you deny that R&T's argument is that according to SR, the "spatial
distance"... around the perimeter (of the rim of the table in the Sagnac
experiment) is not the same CW as CCW according to the rim observer?
>
>On 11 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>>Well, there are Sagnac ring interferometers that remain
>>stationary with respect to the earth-based laboratory.
>>If you don't think that the surface of the Earth is a
>>"SIGNIFICANTLY acceletating systems of reference," then
>>I assume you agree one can one just measure the path length
>>of the ray of light in this experiment with rulers that are
>>stationary to the lab frame?
>
Chan: You assume wrong. I really find your stupidity hard to believe.
>Are you really unable to grasp that "significance" is dependent
>on the context? Are you really unable to grasp that the non-
>inertialness of the Earth's surface is significant for some
>purposes but not for others?
Dennis: So you admit that Earth laboratories represent a "significantly
accelerating system" for measuring, say, the length (spatial distance) of the
perimeter of a desk.
Okay, let's repeat this bit of dialogue then, and I'll add a parenthetical:
**********************************
>>>Chan: I regard significantly accelerating systems of reference
>>>as a little artificial, especially for evaluating physical
>>>phenomena...
>>
D:>>That's unfortunate as all human beings on this Earth live
>>in an accelerating system and conduct length measurements (of perimeters)
with
>>respect to one...
(snip your insulting reply.)
I think it would be best to prefer a theory where length measurements of
perimeters in earth-based labs is a rather simple intuitive thing--that is
consistent with all past measurement procedures, what say you?
Dennis McCarthy
Standeven
Dennis McCarthy wrote:
> >
> >
> >
> >Dennis McCarthy wrote:
> >> If in every 10 miles of a trip from NY to Albany,
> >> you averaged 50 MPH--yet your average velocity for the whole trip was 70
> >> MPH--now, that's a little strange, wouldn't you say?
> >
> Roberts: >It depends upon how those different measurements are made.
>
> Dennis: LOL. Oh, I see.... Ether theory doesn't have this problem, you see-
So in ether theory, one gets the same speed no matter how it is measured?
Standeven
"C.J. Luke" wrote:
That's right. The Selleri paradox is really a calculus gaffe, rather than a contradiction
in
SR. Essentially, the paradox is that
lim lim xy = C
x->0 y->C/x
but
lim lim xy = 0
y->oo x->0
The business with light, clocks, etc. is just dressing.
Luc Bourhis
(in message <20000310155809...@ng-fm1.aol.com>):
> I have a laser on a square desk and three mirrors. The laser is a thin
> red line that *you can see*! The laser is emitted from southwest corner
> hits the mirror on the southeast corner is deflected to the northeast
> corner is deflected to the northwest corner and is deflected back to the
> mirror. The visible lines of the laser form a square from my lab
> perspective--right...along...the perimeter of the table. I have the
> greatest engineers and micrometers in the world in the lab. They measure
> the length of the square table to be 1 meter a side and 4 total meters.
> They measure the actual line of the laser (that they can see!!) and again,
> with their stationary micrometers, they measure 4 total meters.
> Now, tell me, Bourhis, please, what is the path length of that ray of light
> according to my lab partners, the desk and me?
Again and again you forget that in SR space and time mix together and
therefore that the relevant concept is the world line, that is to say the
successive values of (t,x,y,z), and not only the spatial part, called
trajectory in Newtonian physics. An observer moving infinitely slowly along
the rim with its ruler and a electromagnetic pulse propagating along the same
rim do not follow the same world lines. Therefore in the extended SR used
here where spatial lengths are computed as the projection of these world
lines on plane t = constant, the spatial length of the optical path
corresponding to this triangle is different from the spatial length measured
with rulers you have described above. Specifically the optical paths seen by
light rays are different for co- and counter-rotating ones because a time lag
enters these lengths.
Note that it is Lorentz who invented this mixing of space and time, in order
to make his theory of electrons compatible with Michelson & Morley and
Trouton & Noble mainly. The only other way to escape an experimental
falsification is for an Ether theory to postulate that there is no Ether wind
on Earth surface. But this creates even more problems as discussed elsewhere
in this thread. So if I exclude this possibility, the SR concepts I have just
sketched are not avoidable.
> So if I have a theory that reproduces the SR predictions
The only work of yours I have ever seen is a mere Galilean analysis and it
gives a result different from SR for the phase shift of opposite light rays.
Both predictions are compatible with experiments because only the term in v/c
is relevant. However this Galilean analysis does not explain
- the desynchronization of clocks moving slowly along the rim
- the time delay after a round-trip between two particles rotating with the
same speed wrt the rim.
Therefore I do not know any serious element supporting your claim.
> --but uses standard measurement procedures (i.e, with a ruler--not
> with theoretical calculations) for path length, then that theory should be
> preferred?
The most predictive theory, that is to say not your Galilean analysis.
--
Luc Bourhis
Center of Particle Physics/University of Durham
Luc Bourhis
(in message <8ad29p$492$1...@gavrilo.mtu.ru>):
>> So you believe that Ether is dragged not only by the translation of
>> Earth around the Sun but also by the rotation of Earth around its axis,
>> do you ?
>
> It's not belief, it's what has to be tested. Ether co-rotation is ruled out
> by the Earh's rotation Sagnac effect.
Do you mean Ether co-rotation with Earth around itself or with Earth around
the Sun ?
> It's there again under the eupheism of "physical vacuum" - the source and
> sink for particle - anti-particle pairs. Hence, the obvious problems of its
> interaction with conventional matter, and the need for their solution in the
> spirit of materialism and causality. The gas vortex ether theory doesn't
> appeal to me - I advocate I.Sharov's ether crystal model, in which particles
> are regarded as imperfections of the ether crystal lattice. According to it,
> the mass-energy relation is an energy transformation of lattice defect
> energy into vibrational energy in which the inertial mass of ether particles
> associated with the imperfection (mass) remains the same after they are
> incorporated into the regular lattice, but the gravitational mass vanishes;
> the lattice close to an imperfection is normally softer, hence its phonon =
> photon velocity is less, hence, refraction and bending of light. Of Shapiro,
> I know nothing.
There is a problem with this kind of Ether models : crystals have both
longitudinal and transveral waves whereas electromagnetic waves are only
transversal.
>>>> The 3 following objects have different length:
>>>> - the trajectory of a co-rotating particle
>>>> - the trajectory of a counter-rotating particle
>>>> - the rim
>>>> if one works in the non-inertial frame whose world lines are defined by
the
>>>> following parametric equations in some inertial frame:
>>>> x0 = t
>>>> x1 = a cos(w t) - b sin(w t)
>>>> x2 = a sin(w t) + b cos(w t)
>>>> x3 = 0,
>>>> with (a^2+b^2)^(1/2) being the radius of the rim and w its rotation speed.
>
>>> Clearly, a case when sollipsism comes in conflict with reality -- different
>>> results obtained by reasoning with no physical cause.
>
> I beg your pardon, sollipsism, or not, this is the solicited answer, Thank
> you. And after some thought, I begin to see some physical sence in it that
> Dennis, too, could see: the circular route of ligh/particles involves
> reflections, and the condition for them need not be the same for both rays,
> PROVIDED THERE IS AN INHERENT TANGENTIAL ANISOTROPY ON THE RIM. For an
> etherist, the same process must work irrespective of the RF. However, since
> c+.-v produces an accurate result, there's no need to consider the
> contribution of that process.
Which process ?
> The GR, on the other hand claims, that such
> anisotropy is created by the rays/particles themselves interacting with
> what? Right, space-time!
It is the idea, yes.
> So at present, instead of a material ether we have
> the duality of "physical vacuum" and "space-time" to account for various
> classes of physical processes.
The problem is that nobody has ever shown me how to treat all aspects of
Sagnac experiments outside of a framework equivalent to SR. This framework is
in fact a small extension of the "orthodox" SR, with small bits of GR in it.
It is nevertheless equivalent to Ether theories à la LET, if they are
extended in the same way. It is however not equivalent to the kind of
Galilean Ether model Dennis McCarthy has been advocating for ages and
experiments falsify the latter while supporting SR.
So I would like to know how you treat the following aspect of the problem:
- light Sagnac
- desynchronization of clocks moving along the rim
- Sagnac with massive particles moving with the same speed in opposite
direction
>> What is a physical cause ?
>
> The action of a material object responsible for the effect.
Got it.
>>> SR was originally
>>> constructed not as a physical, but as a metric theory - had another signal
>>> carrier (e.g., fast particles) been used, the results would have been
>>> different.
>> You mean that the length of the trajectories would have been different,
>> do you ? You are right but what is funny is that the difference between
>> them does not depend on the speeds of the particles as long as they are
>> the same in the two opposite directions along the rim.
>
> Mine was a general proposition not restricted to the Sagnac set-up. Get an
> idea of it by simply substituting a velocity of some signal carrier for c in
> SR.
This a good remark. In fact it turns out that c is indeed a fundamental
constant not directly related to light, or more generaly to the propagation
of any physical signal. It is a property of spacetime. Then the invariance of
electromagnetism under Lorentz transforms forces the speed of light to be c.
But it is also the speed of propagation of the strong interaction for
example, because this one is also described by a Lorentz invariant model.
>>> Had different signal carriers been used jointly, all ambiguity
>>> (=relativity), would have been removed.
>> ????
>
> The ambiguity = relativity of SR stems simply from the fact that it uses
> only one signal carrier, and, hence is unable to establish experimentally
> the c(v) dependence. This is made possible by the use of two, or more,
> signal carriers.
In SR we have both signals propagating isotropically with the same speed in
any frame and signals which do not. Those who does propagates necessarily at
c because of the structure of Minkovskian spacetime. But in any case there is
no way for an inertial observer to know his speed wrt an another one without
directly interacting with him.
>> I repeat that the particle are not relativistic here. Therefore we have
>> plain Newtonian physics for the definition of mass, momentum and energy.
>> Please read again my argument:
>
> The effect is proportional to v/c^2 (v is the rim's speed), isn't it? In
> rim"s frame, E=m(V+,-v)V^2/2. It is caused by m's dependence on v (rim
> speed). In the rim frame, co- and counter-rotating speeds of equal-energy
> particles ARE DIFFERENT, because of particle mass interaction with static
> ether.
If the masses are different, then de Broglie wave lengths are also different.
However interferences of two waves with the same wave lengths but a relative
phase shift and interferences between waves having different wave lengths can
be discriminated easily, can't they ? The latter is definitively not what is
observed experimentally. Experiences do definitively support that the
particles have the same momentum and energy in both direction, that is to say
the same speed and mass.
> It's simple tedious maths based on experimental values of m(V) and T(V).
> Relativity, to its credit, predicts these dependances, so do alternative
> theories. I have also obtained some of them for the ether crystal model
> using Newtonian physics and symmetry and dimensionality. I long for a clear
> yes - no experiment, and wouldn't waste my time on calculations when
> qualitative results are clear. That's how one makes them. For the clocks,
> the physdical cause of "time dilation" is the effect of ether wind on the
> frequency standard, hence: T = T(o)(1 - (V+,-v)^2/2c^2), where V is the
> translation, and v - the rim's velocities. So, for the difference we obtain:
> difT = 2Lv/c^2, where L= TV is the rim's length.
Usually in Ether theories, T and T0 are the time elapsed respectively in the
frame of the clock and in Ether frame. So you get the result you have quoted
if T(0)V = L, which means that L and V are respectively the length of the rim
and the speed of the clock in the Ether frame. Neglecting terms in (v/c)^2
and (V/c)^2, it seems to be OK even if one considers Lorentz contraction.
However this shows clearly that you do not have a theory equivalent to SR. It
works only because of the approximation you are using. However .....
> For particles, one has to solve E=m(o)(1+(V+,-v)^2/2c^2)V^2/2. So don't
> insist on remarkable SR results.
..... for particles, this does not work anymore since there is no anisotropy.
>>> I mean, it doesn't work, because the clocks on satellites at different
>>> altitudes tick differently.
>> Why does this contradict the equivalence principle ?
>
> Is the situation aboard a satellite any different from that in a falling
> lift cabin Einstein cited to illustrate the principle? A falling cabin is
> equivalent to an inertial RF. All inertrial frames are equivalent, hence all
> falling cabins and satellites are. Observers aboard satellites in different
> orbits synchronise their clocks. Time passes, they check them in the same
> position and find they went astray. Why, if all the satellites were
> equivalent?
When dealing with SR/GR it is very important to state clearly and
unambiguously what frames of reference you consider. For example, in your
example, for an observer on Earth, the tick rates of different satellites
will be different because of Doppler and gravitational shifts. Without
further precision it is difficult to continue.
Luc Bourhis
(in message <20000310153946...@ng-fm1.aol.com>):
>> This procedure gives the length of the rim but not the length of light rays
>> or of particles trajectories rotating along the rim.
>
> Dennis: 1) Can I observe these lengths of light rays or "particle
> trajectories"?
Trajectory was not a well chosen term because it means a curve embedded in
space in Newtonian physics, and this has no meaning in the situation we are
interested in. The correct concept is called world line: see my answer in the
parallel branch you have created in this thread.
As for your question, what do you mean by "observe" ?
> Or do you just take it on faith that this is what the
> trajectories are based on theoretical assumptions (i.e., constancy of c)
> which the experiment is supposed to test.
By definition what is a trajectory depends on the kinematical framework one
is working in. If I use SR, a.k.a. Lorentzian relativity, I have to use the
SR definition and work in fact with world lines. If I use Galilean
relativity, I have to use what you consider as the _true_ definition of a
trajectory. So the answer to your question can not be negative, if constancy
of c is not the only allowed theoretical assumption of course.
> 2) You do realize the Sagnac effect occurs for *stationary* rings in
> laboratories, right?
Strange phrasing. The ring is rotating in the lab frame, isn't it ?
> So you think cars driving around a track in opposite
> directions (CW and CCW) travel different distances, correct?
It depends on the definition of distance, which depends on the definition of
time delay. Anyway in the framework I have sketched in this thread, based on
SR with a touch of GR ideas, one has the following situation:
Consider an observer at a point A on the rim. He sent simultaneously two
signals in opposite directions with the same instantaneous speed v with
respect to him. Then I suppose that the signals are not accelerated or slowed
down during their journey, i.e. : an observer at any point M on the rim
measure an instantaneous speed v for these particles when they pass M. The
main results are:
1) the particles come back to A at different time t1 and t2 according to A's
clock such that t1-t2 does not depend on v but only on the rotating speed of
the rim and on its radius.
2) the lengths l1 and l2 they traveled is also different, in such a way that
v = l1/t1 = l2/t2.
I can hardly be more precise without giving the gory mathematical details and
this should definitively answer this kind of questions, shouldn't it ?
This theoretical description has been implemented experimentaly with
electrons and neutrons. One studies the interferences of the wave functions
associated with co- and counter-rotating particles. I had a look only at
neutrons experiences and I can say that it is an experimental fact that the
two wave functions have the same wave length lambda -- interferences between
two waves with the same lambda are easily distinguished from those between
waves with different lambda's. Then de Broglie equation
lambda = h/(m v)
guaranties that they have also the same instantaneous speed v.
> 3) Consider:
> A) We have a theory which states that some value a/b = K.
> B) Now, we are going to conduct an experiment where we are trying to
> determine the value of a/b and so test the theory. (Such experiments have
> been conducted 100's of times.)
> C) Now, do you know of any experiment in the history of science in which
> the experimenters *reject* the **measured** value of "a" --and instead
> **calculate** a *different* value of "a" based exclusively on an
> *unobservable assumption* that is based on the belief that (get this)
>
> a/b = K.
This is not what is done with SR and I have already answered this objection
above : you can not define what is a and what is b before choosing a theory
of relativity. You are so deeply intoxicated by Galilean relativity that you
do not even notice that you rely on it every time you advocate a natural
definition of a or b. But Galilean relativity is badly ruled out
experimentally, unless you postulate that by magic there is no Ether wind on
the surface of Earth. On the contrary for somebody who knows rather well GR,
what puzzles you so much is not surprising. For example why are you not
equaly upset when you see "bending of light" or "Shapiro time delay"
explained by the influence of a curve spacetime ?
Luc Bourhis
(in message <20000310092249...@ng-cc1.aol.com>):
>> If there is an Ether wind faster that a few 10 m/s, the Galilean
>> analysis you have just sketched is ruled out by modern experiments
>> (Brillet et al, Riis et al, ...)
>
> Dennis: Sorry, the most accurate MM experiment (Brillet) point to an ether
> velocity greater than that.
My goal was just to give a cheap estimate in order to illustrate what I was
saying. I had in mind the experiment of Champeney et al [1] which put an
upper limit of a few centimeters per second on a possible wind in a Galilean
Ether theory. Considering how old are these experiments, the modern ones I
have cited have surely improved this result by several orders of magnitude.
IIRC Brillet et Hall concludes with 1/2 (v/c)^2 < ~ 10^-15. So you see that I
was in fact very generous.
> As I wrote to you and you never responded:
I have responded. Since I am very nice I answer again here.
> You see, there's a slight difficulty here. BH showed an isotropy wrt
> sidereal coordinates to within .13 +/- .22 hz. Yet, for a
> non-Lorentz-contraction ether theory that predicts absolutely no
> rotational velocity of the ether wrt the Earth's surface--and so a
> velocity of light that equals c+/-v--where v is the velocity of the
> rotation of the earth at the latitude of the lab-frame, the prediction
> for the latitude of the BHX lab-frame is for a shift of 31 hz (cos 2
> theta) where theta is the angle of their Fabry-Perot with respect to the
> east. Interestingly, for BH, while the "experiment has been designed to
> be clear in its interpretation and free of suprious effects,"
> nevertheless, Brillet Hall reported a "persistent spurious'(1) effect of
> 2 (theta) amplitude of 17 hz shift (+/- about 35% for the data sent shown)
> at an 'approximately constant phase in the laboratory frame' of about -30
> degrees +/- 10 degrees...." (2) None of the data points was within 10hz of
> isotropy.
I remind you that this 17 Hz shift corresponds to a fractional frequency
shifts of the order of 10^-14, that is to say a lost of one order of
magnitude compared to the final result presented by Brillet et Hall .....
> Although BH did not provide data of the orientation of their apparatus
> with respect to the compass points, the expeirment was not consistent with
> isotropy--but is consistent with ether theories that predict no or small
> ether velocity wrt the ECI frame.
... so indeed an Ether theory had better to have a utterly tiny Ether
velocity wrt Earth frame in order to be compatible with these 17 Hz.
Moreover the 12 h and 24 h averages do not show any anisotropy (fig. 3 after
day ~ 225, i.e. after the end of the test phase). How do you explain this
fact ?
>> You have then two choices as explained later in the message of mine you
>> have just answered.
>
> Those two choices are a contration of the apparatus AND Galilean
> relativity.
You need much more than that. Trouton & Noble or Rayleigh & Brace turned in
pieces the first explanation of Lorentz. He had to come with a "local" time
as he called it and later with the complete Lorentz transforms. Since then
the situation is even more clear : experiments rule out any non-Lorentzian
Ether theory if there is an Ether wind faster than a few meters per second,
and I am very conservative here as explained at the beginning of this
message.
> And slow ether velocity wrt the Earth AND Galilean relativity.
Very slow, yes.
> Now, let me repeat my statement: Galilean nature of light is clearly
> recovered in the experiment--because there are no relevant deformations of
> the measuring devices to counteract this Galilean nature.
>
> Hopefully, we're agreed.
No I disagree. Sagnac experiments show on the contrary that spacetime is not
Galilean at all.
[1] D.C. Champeney, G.R. Isaak, A.M. Khan, Phys. Lett. 7 (1963) 241
G.R. Isaak, Phys. Bull. 21 (1970) 255
See also "Classical Electrodynamics" by J.D. Jackson, section 11.2
Dennis McCarthy
>
>On Fri, 10 Mar 2000 14:22:49 +0000, Dennis McCarthy wrote
>(in message <20000310092249...@ng-cc1.aol.com>):
>
>>> If there is an Ether wind faster that a few 10 m/s, the Galilean
>>> analysis you have just sketched is ruled out by modern experiments
>>> (Brillet et al, Riis et al, ...)
>>
>> Dennis: Sorry, the most accurate MM experiment (Brillet) point to an ether
>> velocity greater than that.
>
I was
>saying. I had in mind the experiment of Champeney et al [1] which put an
>upper limit of a few centimeters per second on a possible wind in a Galilean
>Ether theory.
Dennis: That's false.
D:>> As I wrote to you and you never responded:
>
B:>I have responded. Since I am very nice I answer again here.
>
>> You see, there's a slight difficulty here. BH showed an isotropy wrt
>> sidereal coordinates to within .13 +/- .22 hz. Yet, for a
>> non-Lorentz-contraction ether theory that predicts absolutely no
>> rotational velocity of the ether wrt the Earth's surface--and so a
>> velocity of light that equals c+/-v--where v is the velocity of the
>> rotation of the earth at the latitude of the lab-frame, the prediction
>> for the latitude of the BHX lab-frame is for a shift of 31 hz (cos 2
>> theta) where theta is the angle of their Fabry-Perot with respect to the
>> east. Interestingly, for BH, while the "experiment has been designed to
>> be clear in its interpretation and free of suprious effects,"
>> nevertheless, Brillet Hall reported a "persistent spurious'(1) effect of
>> 2 (theta) amplitude of 17 hz shift (+/- about 35% for the data sent shown)
>> at an 'approximately constant phase in the laboratory frame' of about -30
>> degrees +/- 10 degrees...." (2) None of the data points was within 10hz of
>> isotropy.
Bourhis: >I remind you that this 17 Hz shift corresponds to a fractional
frequency
>shifts of the order of 10^-14, that is to say a lost of one order of
>magnitude compared to the final result presented by Brillet et Hall .....
Dennis: You understand that there are two frames we are talking about right?
One is the sidereal frame and one is the lab frame.
Again, the result that Brillet Hal **presented** was determined with **respect
to stellar coordinates (or the CMBR frame.)***
The result of their data that no one talks about was that they called a
"persistent spurious" effect was a shift of 17 hz with respect to **the
laboratory frame.**
D:>> Although BH did not provide data of the orientation of their apparatus
>> with respect to the compass points, the expeirment was not consistent with
>> isotropy--but is consistent with ether theories that predict no or small
>> ether velocity wrt the ECI frame.
>
B: >... so indeed an Ether theory had better to have a utterly tiny Ether
>velocity wrt Earth frame in order to be compatible with these 17 Hz.
Dennis: 17 hz corresponds to dozens of meter per second--even if the apparatus
is pointing directly east. If it's angled, the velocity would be greater.
Bourhis: >Moreover the 12 h and 24 h averages do not show any anisotropy (fig.
3 after
>day ~ 225, i.e. after the end of the test phase). How do you explain this
>fact ?
Dennis: They figued out wrt sidereal coordinates.
>>> You have then two choices as explained later in the message of mine you
>>> have just answered.
>>
>> Those two choices are a contration of the apparatus AND Galilean
>> relativity.
>
Bourhis: >You need much more than that. Trouton & Noble or Rayleigh & Brace
turned in
>pieces the first explanation of Lorentz. He had to come with a "local" time
>as he called it and later with the complete Lorentz transforms.
Dennis: All you need is EM retardation.
Since then
>the situation is even more clear : experiments rule out any non-Lorentzian
>Ether theory if there is an Ether wind faster than a few meters per second,
>and I am very conservative here as explained at the beginning of this
>message.
Dennis: Your wrong in the beginning of the message as well as just now.
>> And slow ether velocity wrt the Earth AND Galilean relativity.
>
>Very slow, yes.
Dennis: 100's of m/s has not been excluded.
>> Now, let me repeat my statement: Galilean nature of light is clearly
>> recovered in the experiment--because there are no relevant deformations of
>> the measuring devices to counteract this Galilean nature.
>>
>> Hopefully, we're agreed.
>
Bourhis: >No I disagree. Sagnac experiments show on the contrary that spacetime
is not
>Galilean at all.
Dennis: Wow. Not, *that's* got to be the statement of the week. The measured
speed of light is c+/-v in Sagnac.
What result could Sagnac have found in order to show consistency with Galilean
relativity?
Dennis McCarthy
Dennis McCarthy
Dennis McCarthy
of
>Sagnac experiments outside of a framework equivalent to SR.
Dennis: I've explained it to you in laborious detail--but when you are not just
memorizing and regurgitating formulas this can be an excruciatingly agonizing
process.
B: This framework is
>
>in fact a small extension of the "orthodox" SR, with small bits of GR in it.
>It is nevertheless equivalent to Ether theories à la LET, if they are
>extended in the same way. It is however not equivalent to the kind of
>Galilean Ether model Dennis McCarthy has been advocating for ages and
>experiments falsify the latter while supporting SR.
Dennis: That's just about a flat out lie.
Bourhis: >So I would like to know how you treat the following aspect of the
problem:
>- light Sagnac
Dennis: Same way Sagnac did. It takes 3 lines of algebra. You've seen it.
B: >- desynchronization of clocks moving along the rim
Dennis: Oh, dear God. Atomic clocks slow by Lorentz factor when moving wrt
ECI. Are you for real?
B: >- Sagnac with massive particles moving with the same speed in opposite
>direction
Dennis: They, um, don't move at the same speed if they don't return to the
emitter at the same time.
Wow.
Dennis McCarthy
Dennis McCarthy
>
>On Fri, 10 Mar 2000 20:39:46 +0000, Dennis McCarthy wrote
>(in message <20000310153946...@ng-fm1.aol.com>):
>
>>> This procedure gives the length of the rim but not the length of light
>rays
>>> or of particles trajectories rotating along the rim.
>>
>> Dennis: 1) Can I observe these lengths of light rays or "particle
>> trajectories"?
Bourhis: >Trajectory was not a well chosen term because it means a curve
embedded in
>space in Newtonian physics, and this has no meaning in the situation we are
>interested in. The correct concept is called world line: see my answer in the
>
>parallel branch you have created in this thread.
>
>As for your question, what do you mean by "observe" ?
Dennis: asdlkjfaldjf--whoops, sorry, my head just hit the keyboard.
Can you see it and measure it with rulers that you can hold?
D:>> Or do you just take it on faith that this is what the
>> trajectories are based on theoretical assumptions (i.e., constancy of c)
>> which the experiment is supposed to test.
>
Bourhis: >By definition what is a trajectory depends on the kinematical
framework one
>is working in. If I use SR, a.k.a. Lorentzian relativity, I have to use the
>SR definition and work in fact with world lines. If I use Galilean
>relativity, I have to use what you consider
Dennis: Hello? Bourhis? Do you know you measure "distance" of the "path length"
in Galilean relativity. You take a stationary ruler and you put it between the
end point and starting point.
Now, are you saying you can't do that in SR?
Please explain to me how to conduct this measurement in real life. Does it
involve a ruler?
>> 2) You do realize the Sagnac effect occurs for *stationary* rings in
>> laboratories, right?
>
>Strange phrasing. The ring is rotating in the lab frame, isn't it ?
Dennis: You tell me. What happens according to SR if I send light around a
ring that's completely stationary with respect to the lab. Frozen. Glued to
the floor. Doesn't rotate a degrees with respect to the lab. Motionless.
D: >> So you think cars driving around a track in opposite
>> directions (CW and CCW) travel different distances, correct?
>
Bourhis: >It depends on the definition of distance,
Dennis: Ether theory doesn't have such problems and ambiguities. It goes by
the same definition of distance that all people everywhere have always
used--and the same definition that all experimenters use in experiments like MM
or BH, etc..
So now what's the new definition of distance (since 1905) that SR has to use
to maintain consistency with Sagnac experiments?
Bourhis; which depends on the definition of
>time delay.
Dennis: Oh, "distance" is dependent on "time delay."
Bourhis: Anyway in the framework I have sketched in this thread,
Dennis: You can't answer a simple question like that--and you think this is a
preferable theory?
I'll try again. According to SR and SR definitions, do cars driving around
a race track in Colorodo, USA in opposite
directions (CW and CCW) travel the same distance or a different distance?
based on
>SR with a touch of GR ideas, one has the following situation:
>
>Consider an observer at a point A on the rim. He sent simultaneously two
>signals in opposite directions with the same instantaneous speed v with
>respect to him. Then I suppose that the signals are not accelerated or slowed
>
>down during their journey, i.e. : an observer at any point M on the rim
>measure an instantaneous speed v for these particles when they pass M. The
>main results are:
>1) the particles come back to A at different time t1 and t2 according to A's
>clock such that t1-t2 does not depend on v but only on the rotating speed of
>the rim and on its radius.
>2) the lengths l1 and l2 they traveled is also different, in such a way that
>v = l1/t1 = l2/t2.
>
>I can hardly be more precise without giving the gory mathematical details and
>
>this should definitively answer this kind of questions, shouldn't it ?
Dennis: So you are saying (according to SR) cars driving around a race track in
Colorodo, USA in opposite
directions (CW and CCW) travel different distances, right?
What type of rulers are used to measure this distance?
>> 3) Consider:
>> A) We have a theory which states that some value a/b = K.
>> B) Now, we are going to conduct an experiment where we are trying to
>> determine the value of a/b and so test the theory. (Such experiments have
>> been conducted 100's of times.)
>> C) Now, do you know of any experiment in the history of science in which
>> the experimenters *reject* the **measured** value of "a" --and instead
>> **calculate** a *different* value of "a" based exclusively on an
>> *unobservable assumption* that is based on the belief that (get this)
>>
>> a/b = K.
>
Bourhis: >This is not what is done with SR and I have already answered this
objection
>above : you can not define what is a and what is b before choosing a theory
>of relativity.
Dennis: Um, distance is a well understood physical concept that has been used
for centuries regardless of any type of theory. Tell me what type of rulers are
used to measure distance in SR?
Bourhis: You are so deeply intoxicated by Galilean relativity that you
>do not even notice that you rely on it every time you advocate a natural
>definition of a or b.
Dennis: Hello? Measuring a distance with a ruler does not entail galilean
relativity.
You could use stationary rulers and falsify galilean relativity.
But Galilean relativity is badly ruled out
>experimentally, unless you postulate that by magic there is no Ether wind on
>the surface of Earth.
Dennis: Wrong. The ether can be stationary in the ECI.
On the contrary for somebody who knows rather well GR,
>what puzzles you so much is not surprising. For example why are you not
>equaly upset when you see "bending of light" or "Shapiro time delay"
>explained by the influence of a curve spacetime ?
Dennis: That's equally silly too. But before we get there. I'm still wondering
can I use rulers to measure these SR path lengths? Or is this more of a
"theoretical" distance than an empirical one. ;-)
Dennis McCarthy
Dennis McCarthy
>On Fri, 10 Mar 2000 20:58:09 +0000, Dennis McCarthy wrote
>(in message <20000310155809...@ng-fm1.aol.com>):
>
>> I have a laser on a square desk and three mirrors. The laser is a thin
>> red line that *you can see*! The laser is emitted from southwest corner
>> hits the mirror on the southeast corner is deflected to the northeast
>> corner is deflected to the northwest corner and is deflected back to the
>> mirror. The visible lines of the laser form a square from my lab
>> perspective--right...along...the perimeter of the table. I have the
>> greatest engineers and micrometers in the world in the lab. They measure
>> the length of the square table to be 1 meter a side and 4 total meters.
>> They measure the actual line of the laser (that they can see!!) and again,
>> with their stationary micrometers, they measure 4 total meters.
>> Now, tell me, Bourhis, please, what is the path length of that ray of
>light
>> according to my lab partners, the desk and me?
>
Dennis: I didn't forget anything. I'm asking you a direct question and you seem
embarrassed about the answer. Why don't you just be direct. The answer is the
distances are different (according to SR) regardless of what the micrometers
measure, right?
Bourhis: and
>therefore that the relevant concept is the world line,
Dennis: We can't measure this "world line" with a ruler, right?
Bourhis: that is to say the
>successive values of (t,x,y,z), and not only the spatial part, called
>trajectory in Newtonian physics. An observer moving infinitely slowly
Dennis; Whoooa. What observers moving "infinitely slowly." I have a bunch of
normal engineers with micrometers here.
Bourhis: along
>the rim with its ruler and a electromagnetic pulse propagating along the same
>rim do not follow the same world lines. Therefore in the extended SR used
>here where spatial lengths are computed as the projection of these world
>lines on plane t = constant, the spatial length of the optical path
>corresponding to this triangle is different from the spatial length measured
>with rulers you have described above.
Dennis: Ahhh. And this "spatial length of the optical path" is *NOT* what
everyone in the room can clearly see with their eyes as they follow the red
line around the perimeter, right?
Bourhis: Specifically the optical paths seen by
>light rays are different for co- and counter-rotating ones because a time lag>
>enters these lengths.
>
>Note that it is Lorentz who invented this mixing of space and time, in order
>to make his theory of electrons compatible with Michelson & Morley and
>Trouton & Noble mainly. The only other way to escape an experimental
>falsification is for an Ether theory to postulate that there is no Ether wind
>
>on Earth surface. But this creates even more problems as discussed elsewhere
>in this thread. So if I exclude this possibility, the SR concepts I have just
>
>sketched are not avoidable.
Dennis: But you would want to avoid them if possible right? If there is an
ether theory that doesn't postulate such bizarre notoions of "spatial length"
that is consistent with results it should be preferred right?
>> So if I have a theory that reproduces the SR predictions
>
>The only work of yours
(snip)
Dennis: I'll ask again: So IF there is an ether theory that is consistent with
the same predictions of SR--but uses standard measurement procedures (i.e, with
a ruler--not with theoretical calculations) for path length, then that theory
should be
preferred, right?
Dennis McCarthy
Robert Chan
>I'm obviously referring to the SR definition of "spatial length"
>--as that is what is determined by R&T. So I'll restate it for
>you: Do you deny that R&T's argument is that according to SR,
>the "spatial distance"... around the perimeter (of the rim of
>the table in the Sagnac experiment) is not the same CW as CCW
>according to the rim observer?
In the sense of "around the perimeter" that you mean, yes, I
do deny that. Tartaglia's view of this was summarized for you
several posts ago, and it's the same view I've been explaining
to you in more detail since then.
On 11 Mar 2000 djm...@aol.com (Dennis McCarthy) wrote:
>Chan: ... the non-inertialness of the Earth's surface is
>significant for some purposes but not for others...
>
>Dennis: So you admit that Earth laboratories represent a
>"significantly accelerating system" for measuring, say, the
>length (spatial distance) of the perimeter of a desk.
You statement is a complete non-sequitur, i.e., it in no way
follows from my statement. Taking your statement as a clumsily
expressed question, the answer depends on several things, including
the means by which you propose to make the measurement, and the
precision which you wish to achieve. It is certainly true that
there are some measurement techniques (including optical techniques)
which would be affected by the rotation of the Earth, although the
magnitude of this effect would generally be several orders of
magnitude smaller than the precision of the instruments, and
other effects, such as thermal expansion, vibration, etc., would
be much greater.
I say it's best to prefer, as a fundamental theory of principle,
one which is rationally consistent and in agreement with ALL
experiments and observations (not just selected first-order
experiments), past and present, and that is capable of accurately
modeling all the spatial and temporal aspects of physical
phenomena. Then, based on this fundamental theory of principle
it is possible to assess those circumstances in which higher-
order effects are or are not significant, and to use simplified
approximate models for convenience when they have been
determined to be sufficiently accurate for our purposes.
Mark Samokhvalov
Luc Bourhis пишет в сообщении
<01HW.B4F0A3E90...@news.freeserve.net> ...
>On Sat, 11 Mar 2000 9:08:28 +0000, Mark Samokhvalov wrote
>(in message <8ad29p$492$1...@gavrilo.mtu.ru>):
>
>>> So you believe that Ether is dragged not only by the translation of
>>> Earth around the Sun but also by the rotation of Earth around its axis,
>>> do you ?
>>
>> It's not belief, it's what has to be tested. Ether co-rotation is ruled
out
>> by the Earh's rotation Sagnac effect.
>
>Do you mean Ether co-rotation with Earth around itself or with Earth around
>the Sun ?
A strange question for You to ask. Don't You know, that Earh's rotation SE
was measured by Michelson & Gale, and is studied currently by the Canterbury
Ring Laser Project, whereas the orbital effect has never been detected - no
ether axial co-rotation.
Exactly. And all sorts of other modes, if the crystal is of complex
composition. But you'll have to find methods and construct instruments to
detect them. Thus, changes in gravitation must be transported by vibration
modes quite different from the e/m (light), and their velocity could be
expected to be higher.
Changes in the law of reflection resulting from the efffects of ether wind
on the reflector. This effect has no part to play in GPS where the circular
path is obtained not by reflection, but by re-transmission.
>
>> The GR, on the other hand claims, that such
>> anisotropy is created by the rays/particles themselves interacting with
>> what? Right, space-time!
>
>It is the idea, yes.
>
>> So at present, instead of a material ether we have
>> the duality of "physical vacuum" and "space-time" to account for various
>> classes of physical processes.
>
>The problem is that nobody has ever shown me how to treat all aspects of
>Sagnac experiments outside of a framework equivalent to SR. This framework
is
>in fact a small extension of the "orthodox" SR, with small bits of GR in
it.
>It is nevertheless equivalent to Ether theories а la LET, if they are
>extended in the same way. It is however not equivalent to the kind of
>Galilean Ether model Dennis McCarthy has been advocating for ages and
>experiments falsify the latter while supporting SR.
>
>So I would like to know how you treat the following aspect of the problem:
>- light Sagnac
>- desynchronization of clocks moving along the rim
>- Sagnac with massive particles moving with the same speed in opposite
>direction
Apparently, You have no habit of reading a message to the end before
replying to it.
It's the ether wind problem - you claim it to be insoluble. Indeed, it
hasn't up to now been solved, possibly, because of ether drag by the Earth's
gravitational field, but there are all sorts of methods that could solve it.
You mean, the test will be in the quadratic terms? ..
>
>> For particles, one has to solve E=m(o)(1+(V+,-v)^2/2c^2)V^2/2. So don't
>> insist on remarkable SR results.
>
>..... for particles, this does not work anymore since there is no
anisotropy.
Isn't the particle case an exact replica of the clock one? What's wrong with
the formula?
>
>>>> I mean, it doesn't work, because the clocks on satellites at different
>>>> altitudes tick differently.
>
>>> Why does this contradict the equivalence principle ?
>>
>> Is the situation aboard a satellite any different from that in a falling
>> lift cabin Einstein cited to illustrate the principle? A falling cabin is
>> equivalent to an inertial RF. All inertrial frames are equivalent, hence
all
>> falling cabins and satellites are. Observers aboard satellites in
different
>> orbits synchronise their clocks. Time passes, they check them in the same
>> position and find they went astray. Why, if all the satellites were
>> equivalent?
>
>When dealing with SR/GR it is very important to state clearly and
>unambiguously what frames of reference you consider. For example, in your
>example, for an observer on Earth, the tick rates of different satellites
>will be different because of Doppler and gravitational shifts. Without
>further precision it is difficult to continue.
That's sollipsism at its best - the observers from different satellites
will never be able to agree. It wasn't that bad in early "twin paradox"
examples - the twin astronauts returning from different directions were able
to do that.
Luc Bourhis
(in message <20000311214044...@ng-cb1.aol.com>):
>> My goal was just to give a cheap estimate in order to illustrate what I
>> was saying. I had in mind the experiment of Champeney et al [1] which put
>> an upper limit of a few centimeters per second on a possible wind in a
>> Galilean Ether theory.
>
> Dennis: That's false.
Usually in a scientific discussion one comes with arguments. I have given
precise references, including the well-known book of Jackson you should be
able to find easily. So you have to disprove his section 11.2. Here is a
flavour of it.
The experiment of Champeney et al. measures the Doppler frequency shift f1-f2
between a source and a detector placed at the two extremities of a diameter
of a disk of radius R = 4 cm rotating with an angular speed w = 7728 s^-1. If
f0 is the frequency of the wave in the lab frame, one has
(f1-f2)/f0 = 2 w R/c^2 sin(wt) V0
where V0 is the component of the Ether wind perpendicular to the axis of
rotation -- one has postulated a Galilean Ether. Champeney et al measured
(f1-f2)/f0 and concluded that V0 = 1.6 +/- 2.8 m/s and in an improved
experiment made by Isaak [2], the limit was decreased to V0 ~ 5 cm/s.
But there are more modern experiments based on the same ideas. For example
Riis et al [1] who concluded that they have obtained a 10-fold improvement
compared to Isaak [2]. With the value quoted above, this gives an Ether wind
of the order of a few mm/s.
>> I remind you that this 17 Hz shift corresponds to a fractional frequency
>> shifts of the order of 10^-14, that is to say a lost of one order of
>> magnitude compared to the final result presented by Brillet et Hall .....
>
> Dennis: You understand that there are two frames we are talking about
> right? One is the sidereal frame and one is the lab frame. Again, the
> result that Brillet Hal **presented** was determined with **respect to
> stellar coordinates (or the CMBR frame.)*** The result of their data that
> no one talks about was that they called a "persistent spurious" effect was
> a shift of 17 hz with respect to **the laboratory frame.**
This does not change anything to my remark about the order of magnitude of
this effect. Since the fractional frequency shift for a Galilean Ether is at
most 1/2 (v/c)^2, these 17 Hz shift correspond to v ~ 40 m/s. This value
supports my previous statements and I do therefore feel no urgent need to
make a detailled analysis of your criticism of Brillet et Hall.
>> ... so indeed an Ether theory had better to have a utterly tiny Ether
>> velocity wrt Earth frame in order to be compatible with these 17 Hz.
>
> Dennis: 17 hz corresponds to dozens of meter per second--even if the
> apparatus is pointing directly east. If it's angled, the velocity would
> be greater.
The maximum magnitude of the effect is of the order of (v/c)^2 because
cosinus and sinus are smaller than 1 and as shown below this leads to a few
10 m/s.
>> Moreover the 12 h and 24 h averages do not show any anisotropy (fig. 3
>> after day ~ 225, i.e. after the end of the test phase). How do you
>> explain this fact ?
>
> Dennis: They figued out wrt sidereal coordinates.
So it appears that you want me to explain what occured in the lab frame. From
what is explained in the article, I do not know. But I am not the most
qualified person to discuss such experimental papers. Since the whole
scientific community is convinced by the conclusions of these gentlemen, it
appears that this problem has been addressed, understood and settled. However
you will have to ask somebody else for an explanation.
>>>> You have then two choices as explained later in the message of mine you
>>>> have just answered.
>>>
>>> Those two choices are a contration of the apparatus AND Galilean
>>> relativity.
>>
>> You need much more than that. Trouton & Noble or Rayleigh & Brace turned
>> in pieces the first explanation of Lorentz. He had to come with a "local"
>> time as he called it and later with the complete Lorentz transforms.
>
> Dennis: All you need is EM retardation.
You can play with words as long as you want, this will not transform the
theory Lorentz exposed in his 1904 paper in what it is not. The case we are
just discussing is an Ether theory which relates the spacetime coordinates
measured by an observer in Ether frame to those measured by an observer on a
body moving in Ether with Lorentz transforms. This is not debatable by
anybody who read his paper published in 1904 or the lectures he gave in 1906
and from which he wrote the book "The Theory of Electrons". If you are
interested I have given extensive citations of it in the thread "Step by
Step, SR and LET".
>> Since then the situation is even more clear : experiments rule out any
>> non-Lorentzian Ether theory if there is an Ether wind faster than a few
>> meters per second, and I am very conservative here as explained at the
>> beginning of this message.
>
> Dennis: Your wrong in the beginning of the message as well as just now.
For the moment I have brought most of the arguments in this discussion. What
are yours ?
>>> And slow ether velocity wrt the Earth AND Galilean relativity.
>>
>> Very slow, yes.
>
> 100's of m/s has not been excluded.
In my humble opinion, a few 10 m/s is at most what you can ask for to a very
generous guy. So now is there really any need to quibble about this value of
the Ether wind ? Is your IGS refuted by a too big value of it ?
[1] Riis et al, Phys. Rev. Lett. 60 (1988) 81
[2] G.R. Isaak, Phys. Bull. 21 (1970) 255
Luc Bourhis
^^^^^^^^^^^^^^^
Argh !!! This man is hunting me :-)
>> The problem is that nobody has ever shown me how to treat all aspects of
>> Sagnac experiments outside of a framework equivalent to SR.
>
> I've explained it to you in laborious detail--but when you are not just
> memorizing and regurgitating formulas this can be an excruciatingly
> agonizing process.
You know you should treat me more carefuly because I am an endangered species
on this forum, the relativists who do not insult you and who do try to
provide detailled arguments for their rebuttals. By the by what a massive
butcher this Chan; I hope you enjoy your wrestling with him. He is almost as
good as Davidson :-)
>> This framework is in fact a small extension of the "orthodox" SR, with
>> small bits of GR in it. It is nevertheless equivalent to Ether theories à
>> la LET, if they are extended in the same way. It is however not
>> equivalent to the kind of Galilean Ether model Dennis McCarthy has been
>> advocating for ages and experiments falsify the latter while supporting
>> SR.
>
> That's just about a flat out lie.
Well you know everything is relative for me and therefore I have difficulties
distinguishing truths and lies :-)
>> So I would like to know how you treat the following aspect of the problem:
>> - light Sagnac
>
> Same way Sagnac did. It takes 3 lines of algebra. You've seen it.
You know that it is not enough for me. I can't remember equations if they do
not fill one page with tensor notations :-)
>> - desynchronization of clocks moving along the rim
>
> Oh, dear God. Atomic clocks slow by Lorentz factor when moving wrt
> ECI. Are you for real?
You know I am but you would like I were not.
>> - Sagnac with massive particles moving with the same speed in opposite
>> direction
>
> They, um, don't move at the same speed if they don't return to the
> emitter at the same time.
> Wow.
I am sure that your roaring would impress even the wildest polar bear but for
reasons uknown to men I am not even entertained by them :-) Anyway as Sun-Tzu
said : "Those who can deny reality without disastrous consequences are the
luckiest men" and indeed I envy you because I can simply not do so.
Luc Bourhis
(in message <20000311214107...@ng-cb1.aol.com>):
>> No I disagree. Sagnac experiments show on the contrary that spacetime is
>> not Galilean at all.
>
> Dennis: Wow. Not, *that's* got to be the statement of the week.
Yaahoooo ! To be in Dennis's charts is a terrific honour :-)
> The measured speed of light is c+/-v in Sagnac.
Wow. It is hard to imagine that I have been able to live until now without
knowing that. Thanks for the news :-)
> What result could Sagnac have found in order to show consistency with
> Galilean relativity?
Life on Mars ?
Luc Bourhis
(in message <20000311221625...@ng-cb1.aol.com>):
>> Again and again you forget that in SR space and time mix together
>
> I didn't forget anything.
Lucky you. :-)
> I'm asking you a direct question and you seem embarrassed about the
> answer.
Do you want to start an psychoanalysis of mine right now ? :-)
> Why don't you just be direct.
To work with curved spacetimes too often tends to twist the mind. :-)
> The answer is the distances are different (according to SR) regardless of
> what the micrometers measure, right?
You have very peculiar fantasms, you know. Anyway nice try to project your
thoughts in my mind but it did not work :-)
>> and
>> therefore that the relevant concept is the world line,
>
> Dennis: We can't measure this "world line" with a ruler, right?
We can associate to it a spatial length which can be measured with rulers.
>> that is to say the
>> successive values of (t,x,y,z), and not only the spatial part, called
>> trajectory in Newtonian physics. An observer moving infinitely slowly
>
> Dennis; Whoooa. What observers moving "infinitely slowly." I have a bunch of
> normal engineers with micrometers here.
Sorry I forgot that american engineers are fast :-)
>> along the rim with its ruler and a electromagnetic pulse propagating
>> along the same rim do not follow the same world lines. Therefore in the
>> extended SR used here where spatial lengths are computed as the
>> projection of these world lines on plane t = constant, the spatial length
>> of the optical path corresponding to this triangle is different from the
>> spatial length measured with rulers you have described above.
>
> Dennis: Ahhh. And this "spatial length of the optical path" is *NOT* what
> everyone in the room can clearly see with their eyes as they follow the red
> line around the perimeter, right?
It is not.
>> Specifically the optical paths seen by light rays are different for co-
>> and counter-rotating ones because a time lag enters these lengths.
>>
>> Note that it is Lorentz who invented this mixing of space and time, in
>> order to make his theory of electrons compatible with Michelson & Morley
>> and Trouton & Noble mainly. The only other way to escape an experimental
>> falsification is for an Ether theory to postulate that there is no Ether
>> wind on Earth surface. But this creates even more problems as discussed
>> elsewhere in this thread. So if I exclude this possibility, the SR
>> concepts I have just sketched are not avoidable.
>
> But you would want to avoid them if possible right?
You know, contrary to you, I do not want anything a priori.
> If there is an
> ether theory that doesn't postulate such bizarre notoions of "spatial length"
> that is consistent with results it should be preferred right?
You mean consistent with your own fine tuned understanding of the results ?
> Dennis: I'll ask again: So IF there is an ether theory that is consistent
> with the same predictions of SR--but uses standard measurement procedures
> (i.e, with a ruler--not with theoretical calculations) for path length,
> then that theory should be preferred, right?
Stop trying to use your mental power on me. I am too virtual to be
hypnotized. :-)
Luc Bourhis
(in message <20000311220448...@ng-cb1.aol.com>):
>>> Dennis: 1) Can I observe these lengths of light rays or "particle
>>> trajectories"?
>
>> Trajectory was not a well chosen term because it means a curve embedded
>> in space in Newtonian physics, and this has no meaning in the situation
>> we are interested in. The correct concept is called world line: see my
>> answer in the parallel branch you have created in this thread.
>>
>> As for your question, what do you mean by "observe" ?
>
> Dennis: asdlkjfaldjf--whoops, sorry, my head just hit the keyboard.
I hope it was painful :-)
> Can you see it and measure it with rulers that you can hold?
To see is not a very clear scientific concept. But any measurement involves
rulers. Note that it is often a gedanken experiment : nobody has ever
measured the trajectory of the center of mass of a plane with such devices.
>> By definition what is a trajectory depends on the kinematical framework
>> one is working in. If I use SR, a.k.a. Lorentzian relativity, I have to
>> use the SR definition and work in fact with world lines. If I use
>> Galilean relativity, I have to use what you consider
>
> Dennis: Hello? Bourhis? Do you know you measure "distance" of the "path
> length" in Galilean relativity. You take a stationary ruler and you put
> it between the end point and starting point.
If the path is not straight, you have to add an infinite number of
infinitesimal lengths measured by moving slowly along the curve.
> Now, are you saying you can't do that in SR?
And this is what we do in SR.
> Please explain to me how to conduct this measurement in real life. Does it
> involve a ruler?
Yes but the problem is now to glue together all the infinitesimal
measurements we have made and this procedure depends on the theory of
relativity one is using. You take for granted that Galilean relativity rules,
even if it is at odd with tons of experimental evidences. On the contrary any
sensible physicist uses a Minkovskian spacetime, at least locally. This makes
a big difference.
>>> 2) You do realize the Sagnac effect occurs for *stationary* rings in
>>> laboratories, right?
>>
>> Strange phrasing. The ring is rotating in the lab frame, isn't it ?
>
> Dennis: You tell me. What happens according to SR if I send light around a
> ring that's completely stationary with respect to the lab. Frozen. Glued to
> the floor. Doesn't rotate a degrees with respect to the lab. Motionless.
Ah yes, stupid me ! The Earth is in rotation. This is by the way how the
Sagnac effects with electrons and neutrons is studied because it is quite
hard to install the experiment on a rotating platform.
>>> So you think cars driving around a track in opposite
>>> directions (CW and CCW) travel different distances, correct?
>>
>>It depends on the definition of distance,
>
> Ether theory doesn't have such problems and ambiguities.
Cato would have been very proud of you. But you should also put this at the
end of each of your messages if you want to imitate completely his style.
> It goes by the same definition of distance that all people everywhere have
> always used--and the same definition that all experimenters use in
> experiments like MM or BH, etc..
> So now what's the new definition of distance (since 1905) that SR has to
> use to maintain consistency with Sagnac experiments?
With rulers shrinking when they move in Ether and simultaneity being a
relative notion, it is not surprising that length measurement becomes
suddenly less trivial. But I am wasting my time.
>> which depends on the definition of time delay.
>
> Dennis: Oh, "distance" is dependent on "time delay."
In order to measure the length of an object, one has to make simultaneous
measurements of position.
>> Anyway in the framework I have sketched in this thread,
>
> Dennis: You can't answer a simple question like that--and you think this is a
> preferable theory?
I apologize for doing real physics.
> I'll try again. According to SR and SR definitions, do cars driving around
> a race track in Colorodo, USA in opposite directions (CW and CCW) travel
> the same distance or a different distance?
In the frame of the track, different distances.
>> [...]
> So you are saying (according to SR) cars driving around a race track in
> Colorodo, USA in opposite directions (CW and CCW) travel different
> distances, right? What type of rulers are used to measure this distance?
>> This theoretical description has been implemented experimentaly with
>> electrons and neutrons. One studies the interferences of the wave
>> functions associated with co- and counter-rotating particles. I had a
>> look only at neutrons experiences and I can say that it is an
>> experimental fact that the two wave functions have the same wave length
>> lambda -- interferences between two waves with the same lambda are easily
>> distinguished from those between waves with different lambda's. Then de
>> Broglie equation
>> lambda = h/(m v)
>> guaranties that they have also the same instantaneous speed v.
I note that you have edited this fundamental paragraph of mine which shows
that your Galilean analysis is refuted experimentally. Instead of your rather
uninteresting questions about cars you should have addressed this very
important issue.
> Dennis: Um, distance is a well understood physical concept that has been
> used for centuries regardless of any type of theory.
The apparition of Lorentz Ether was a Earthquake.
> Tell me what type of rulers are used to measure distance in SR?
The usual ones.
>> You are so deeply intoxicated by Galilean relativity that you do not even
>> notice that you rely on it every time you advocate a natural definition
>> of a or b.
>
> Dennis: Hello? Measuring a distance with a ruler does not entail galilean
> relativity.
> You could use stationary rulers and falsify galilean relativity.
You do implicitely postulate an absolute time and an absolute space. This is
what allows you to have trajectories as 1-curves embedded in a 3-dimensional
euclidian space.
>> But Galilean relativity is badly ruled out
>> experimentally, unless you postulate that by magic there is no Ether wind
>> on the surface of Earth.
>
> Dennis: Wrong. The ether can be stationary in the ECI.
The speed of a point at the surface of Earth in the ECI is ~ 500 m/s, isn't
it ? Such an Ether wind is ruled out by at least one order of magnitude. I
have pointed out to you experiments with limits as small as 5 cm/s for the
this wind.
Dennis McCarthy
Dennis: And this "gaffe" is circumvented by relativists discounting what is
measured by rulers as "spatial distance" --and instead calculating "spatial
distance" with pen and paper based on the assumption that the speed of light is
constant.
Dennis McCarthy
Dennis McCarthy
> ^^^^^^^^^^^^^^^
Dennis: Well, stop leaving such obvious blood trails. ;-)
B:>>> The problem is that nobody has ever shown me how to treat all aspects of
>>> Sagnac experiments outside of a framework equivalent to SR.
>>
>>D: I've explained it to you in laborious detail--but when you are not just
>> memorizing and regurgitating formulas this can be an excruciatingly
>> agonizing process.
>
B: >You know you should treat me more carefuly because I am an endangered
species
>
>on this forum, the relativists who do not insult you and who do try to
>provide detailled arguments for their rebuttals. By the by what a massive
>butcher this Chan; I hope you enjoy your wrestling with him. He is almost as
>good as Davidson :-)
Dennis: You are right. And I apologize.
>>> This framework is in fact a small extension of the "orthodox" SR, with
>>> small bits of GR in it. It is nevertheless equivalent to Ether theories à
>>> la LET, if they are extended in the same way. It is however not
>>> equivalent to the kind of Galilean Ether model Dennis McCarthy has been
>>> advocating for ages and experiments falsify the latter while supporting
>>> SR.
>>
>> That's just about a flat out lie.
>
B: >Well you know everything is relative for me and therefore I have
difficulties
>
>distinguishing truths and lies :-)
Dennis: Well, you show good humor there. But I am frustrated by comments that
you have made, I have refuted, and that you make again.
>>> So I would like to know how you treat the following aspect of the problem:
>
>>> - light Sagnac
>>
>> Same way Sagnac did. It takes 3 lines of algebra. You've seen it.
>
B: >You know that it is not enough for me. I can't remember equations if they
do
>not fill one page with tensor notations :-)
Dennis: But you can easily refer to Sagnac again--or my writings. It is not
quite fair to argue that you don't understand the simple ether explanation to
light Sagnac
B: >>> - desynchronization of clocks moving along the rim
>>
D:>> Oh, dear God. Atomic clocks slow by Lorentz factor when moving wrt
>> ECI. Are you for real?
>
Bourhis: >You know I am but you would like I were not.
Dennis: Do you really not understand that clock retardation is predicted by
ether theories--and the clock "desynching" is exclusively an SR problem?
B:>>> - Sagnac with massive particles moving with the same speed in opposite
>>> direction
>>
D:>> They, um, don't move at the same speed if they don't return to the
>> emitter at the same time.
>> Wow.
>
B: >I am sure that your roaring would impress even the wildest polar bear but
for
>
>reasons uknown to men I am not even entertained by them :-) Anyway as Sun-Tzu
>
>said : "Those who can deny reality without disastrous consequences are the
>luckiest men" and indeed I envy you because I can simply not do so.
Dennis: Well, let's take the reality of the situation step by step:
Speed is distance/time.
Rim observer measures same distance but different time.
So in your view of reality, how is that "the same speed in opposite direction"?
Dennis McCarthy
Dennis McCarthy
>
>
>On Sun, 12 Mar 2000 3:04:48 +0000, Dennis McCarthy wrote
>(in message <20000311220448...@ng-cb1.aol.com>):
>
>>>> Dennis: 1) Can I observe these lengths of light rays or "particle
>>>> trajectories"?
>>
>>> Trajectory was not a well chosen term because it means a curve embedded
>>> in space in Newtonian physics, and this has no meaning in the situation
>>> we are interested in. The correct concept is called world line: see my
>>> answer in the parallel branch you have created in this thread.
>>>
>>> As for your question, what do you mean by "observe" ?
>>
>> Dennis: asdlkjfaldjf--whoops, sorry, my head just hit the keyboard.
>
>
D:>> Can you see it and measure it with rulers that you can hold?
>
B: >To see is not a very clear scientific concept.
Dennis: Bourhis is now frantic:
"What do you mean by "observe"? "What do you mean by "see"? " I don't
understand these words and they don't have scientific meaning"
A quick power search on "Bourhis, see, and observe," gives 229 posts. That's
229 posts, most of which you were involved with, in which you use both the
terms "see" and "observe" yourself or at least read them in replies from
others--and yet you never had a problem understanding those terms. Now, when I
ask you a direct question about whether you can observe or see these path
trajectories, you suddenly don't understand the meaning of these terms.
Here are two statements below. Emphasis added:
Bourhis:" ... but indeed one performs quantum experiment and **observe** the
interferences between the particles going in opposite directions."
Bourhis: "Why do we not *see* such phenomena ?"
I am essentially using the terms the way you use them above--and the way
everyone on the planet understands them to mean.
Bourhis: But any measurement involves
>rulers.
Dennis: Then explain to me how you use the rulers to measure this spatial
distance according to SR.
Bourhis; Note that it is often a gedanken experiment :
Dennis; I'm referring to a real Sagnac experiment.
>>> By definition what is a trajectory depends on the kinematical framework
>>> one is working in. If I use SR, a.k.a. Lorentzian relativity, I have to
>>> use the SR definition and work in fact with world lines. If I use
>>> Galilean relativity, I have to use what you consider
>>
>> Dennis: Hello? Bourhis? Do you know you measure "distance" of the "path
>> length" in Galilean relativity. You take a stationary ruler and you put
>> it between the end point and starting point.
>
Bourhis; >If the path is not straight, you have to add an infinite number of
>infinitesimal lengths measured by moving slowly along the curve.
Dennis; Talking about *real* experiments here. The distance between the
mirrors is always straight wrt the lab frame.
>> Now, are you saying you can't do that in SR?
>
B:>And this is what we do in SR.
Dennis: Again, when you take a stationary ruler and you put it between the end
point and starting point (in Sagnac) you don't measure distance according to
SR. Please explain to me how you do this.
>> Please explain to me how to conduct this measurement in real life. Does it
>> involve a ruler?
>
Bourhis; >Yes but the problem is now to glue together all the infinitesimal
>measurements
Dennis: Ether theory doesn't have such problems. And there is no
"infinitesimal measurement" ever made in the history of science.
Bourhis; we have made and this procedure depends on the theory of
>relativity one is using.
Dennis: Please do not suggest that normal measuring methods (ie., the ones used
by the rest of the planet) entail Galilean relatitivity. Now, please explain
to me how to conduct this measurement in real life.
Bourhis; You take for granted that Galilean relativity rules,
>
>even if it is at odd with tons of experimental evidences.
Dennis: This is simply false and I suspect you know it.
Bourhis; On the contrary any
>
>sensible physicist uses a Minkovskian spacetime, at least locally. This makes
>
>a big difference.
Denins; Please..explain..to...me...how...to...make...the...measurement.
>>>> 2) You do realize the Sagnac effect occurs for *stationary* rings in
>>>> laboratories, right?
>>>
B:>>> Strange phrasing. The ring is rotating in the lab frame, isn't it ?
>>
>> Dennis: You tell me. What happens according to SR if I send light around
>a
>> ring that's completely stationary with respect to the lab. Frozen. Glued
>to
>> the floor. Doesn't rotate a degrees with respect to the lab. Motionless.
>
B: >Ah yes, stupid me ! The Earth is in rotation. This is by the way how the
>Sagnac effects with electrons and neutrons is studied because it is quite
>hard to install the experiment on a rotating platform.
>
>>>> So you think cars driving around a track in opposite
>>>> directions (CW and CCW) travel different distances, correct?
>>>
>>>It depends on the definition of distance,
>>
>> Ether theory doesn't have such problems and ambiguities.
>
B: >Cato would have been very proud of you. But you should also put this at the
>end of each of your messages if you want to imitate completely his style.
>>> which depends on the definition of time delay.
>>
>> Dennis: Oh, "distance" is dependent on "time delay."
>
>In order to measure the length of an object, one has to make simultaneous
>measurements of position.
Dennis; No one has ever done that in the history of experiment. Now please
explain to me how you measure distance with rulers according to SR in real life
experiments.
>>> Anyway in the framework I have sketched in this thread,
>>
>> Dennis: You can't answer a simple question like that--and you think this is
>a
>> preferable theory?
>
B:>I apologize for doing real physics.
Dennis: Please explain to me the experimental measuring procedure.
>> I'll try again. According to SR and SR definitions, do cars driving around
>
>> a race track in Colorodo, USA in opposite directions (CW and CCW) travel
>> the same distance or a different distance?
>
B: >In the frame of the track, different distances.
Dennis: Ahh, I see. Now, how do you measure this interesting fact?
Dennis McCarthy
Dennis McCarthy
>>> experimental fact that the two wave functions have the same wave length
>>> lambda -- interferences between two waves with the same lambda are easily
>>> distinguished from those between waves with different lambda's.
Dennis: Sigh. The frequency of the wave is obviously varying--depending on
rotational velocity. That's what the Sagnac effect is.
Bourhis: Then de
>>> Broglie equation
>>> lambda = h/(m v)
>>> guaranties that they have also the same instantaneous speed v.
D: Sigh. What is *observed* in the experiment is that the two objects travel
different distances in the same time. That means what is *observed* is that
they are travelling at different speeds.
All the rest is theory and speculation--and rather goofy speculation at that.
Dennis McCarthy