On Tuesday, July 13, 2021 at 10:03:27 PM UTC-5, tjrob137 wrote:

> You seem to be on a quest to resurrect LET -- that's hopeless. History
> and theoretical physics are against you; experimental physics is also
> against you (because of experiments involving the strong, weak, and
> gravitational interactions).

Although each force of nature would require its own ether, the
signal propagation speed of each force is c. Why should that be so?
Sound waves do not travel at the same speed as water ripples,
P waves travel faster than S waves, Love waves travel faster than
Rayleigh waves, etc. LET has no answer for how such vastly different
phenomena as strong, weak, gravitational and electromagnetic
interactions somehow share the same signal propagation speed.

On Wednesday, 14 July 2021 at 10:52:35 UTC+2, prokaryotic.c...@gmail.com wrote:
> On Tuesday, July 13, 2021 at 10:03:27 PM UTC-5, tjrob137 wrote:
>
> > You seem to be on a quest to resurrect LET -- that's hopeless. History
> > and theoretical physics are against you; experimental physics is also
> > against you (because of experiments involving the strong, weak, and
> > gravitational interactions).
>
> Although each force of nature would require its own ether, the
> signal propagation speed of each force is c. Why should that be so?
> Sound waves do not travel at the same speed as water ripples,
> P waves travel faster than S waves, Love waves travel faster than
> Rayleigh waves, etc. LET has no answer for how such vastly different
> phenomena as strong, weak, gravitational and electromagnetic
> interactions somehow share the same signal propagation speed.

And do they really, or is it just an obvious consequence of
our obviously obvious Holiest Postulate?

Prokaryotic Capase Homolog wrote:

> On Tuesday, July 13, 2021 at 10:03:27 PM UTC-5, tjrob137 wrote:
>
>> You seem to be on a quest to resurrect LET -- that's hopeless. History
>> and theoretical physics are against you; experimental physics is also
>> against you (because of experiments involving the strong, weak, and
>> gravitational interactions).
>
> Although each force of nature would require its own ether, the signal
> propagation speed of each force is c. Why should that be so? Sound waves
> do not travel at the same speed as water ripples,
> P waves travel faster than S waves, Love waves travel faster than
> Rayleigh waves, etc. LET has no answer for how such vastly different
> phenomena as strong, weak, gravitational and electromagnetic
> interactions somehow share the same signal propagation speed.

you mix tutifruti apparently being uneducated. Waves, traverse and
longitudinal, are merely about medium and interfaces. Not origins.

On 7/9/21 2:53 PM, Arthur Adler wrote:
> On Friday, July 9, 2021 at 11:37:10 AM UTC-7, tjrob137 wrote:
>>>> The earth's velocity varies by ~ 0.0002 c relative to the
>>>> "fixed stars" or the CMBR dipole=0 frame, or the ICRF used by
>>>> astronomers. But spectroscopy shows no variation [in rate of
>>>> proper time] correlated with that variation in velocity.....
>>>
>>> What do you mean by that?
>>
>> I mean precisely what I said: frequencies measured in atomic
>> spectroscopy show no variations that correlate with earth's
>> varying velocity relative to any of those frames mentioned above.
>
> Your statement still makes no sense.

Then you need to learn how to read, as well as the context of how
typical scientific measurements are performed.

Hint: atomic spectroscopy is performed in a lab on
earth, measuring emissions from atoms approximately
at rest in that lab.

Yes, the constancy of those measurements at different times of the year
is a demonstration of local Lorentz invariance -- that's why I mentioned
it as a direct demonstration of LLI.

Hint: the earth's velocity varies by ~ 0.0002 c relative
to any of those frames. A constant measurement has no
correlation with that variation.

> Letting x,t denote the local intertial coordinates in which the CMBR
> is isotropic, [...]
>> Do you really think that atomic spectroscopy is performed in the
>> CMBR dipole=0 frame?
>
> You are the one who raised the "CMBR dipole=0 frame",

Not really, it was the post to which I was responding that discussed
"clocks really do tick different on undergoing motion", and I merely
made that explicit by discussion motion relative to any of several
obvious frames.

> but you can use any other frame you like, and the point is still the
> same: What you are saying is either self-evidently wrong or it is an
> empty tautology of no physical significance.

Not true. Spectroscopists invariably use the locally inertial frame in
which their laboratory is instantaneously at rest during their
measurements (effective duration typically << microseconds). So the
constancy of their results can be interpreted as tests of local
Lorentz invariance, WHICH IS WHY I MENTIONED THIS AT ALL.

>> The fact that spectroscopic frequency measurements don't vary as
>> the earth varies its velocity wrt the CMBR dipole=0 frame is just
>> an instance of Lorentz invariance.
>
> Huh? Are you claiming that the frequencies of the light received
> from distant stars and galaxies don't vary as the earth's orbital
> velocity varies?

No. You are supposed to read what I write. I said that SPECTROSCOPIC
FREQUENCY MEASUREMENTS do not vary. I said nothing at all about light
from distant astronomical objects - atomic spectroscopy is a local
measurement of atoms approximately at rest in the lab.

Hint: astronomers do indeed measure the spectra of
distant objects, but doing that is called astronomy.

>> Please explain how one can compare the tick rates of
>> relatively-moving clocks without signals.
>
> In the usual way: Clock rates dtau/dt are defined in terms of
> coordinate systems x,t. [...]

Sure, but to MEASURE that for a clock moving relative to those
coordinates requires signals. You have completely failed to answer my
challenge by merely repeating your usual detailed description that is
irrelevant here.

> [... repetitions of that failure]

I probably won't continue, as you are just arguing about the meanings of
words, unless you actually manage to meet my challenge above.

Tom Roberts

On Wednesday, July 14, 2021 at 11:44:48 AM UTC-7, tjrob137 wrote:
> Frequencies measured in atomic spectroscopy show no variations
> that correlate with earth's varying velocity relative to any of those
> frames [such as the CMBR isotropic frame] mentioned above.

Your statement still makes no sense. Letting x,t denote the local intertial coordinates in which the CMBR is isotropic, and letting tau denote the time of a standard clock on earth (neglecting gravitational effects), we have dtau/dt = sqrt(1 - v^2/c^2), so the rate does indeed vary with speed as predicted by special relativity. Are you just saying that in terms of local inertial coordinates X,T in which the clock is at rest we have dtau/dT = 1?

> Hint: atomic spectroscopy is performed in a lab on
> earth, measuring emissions from atoms approximately
> at rest in that lab.

That is astoundingly stupid. Spectroscopy is routinely performed by astronomers to examine the chemical compositions of distant astronomical objects, and that's the only context in which your statement could have been anything other than astoundingly infantile. To see if that might be the stupid tautology you were asserting, I specifically asked "Are you just saying that in terms of local inertial coordinates X,T in which the clock is at rest we have dtau/dT = 1?" The correct answer for you to give would be "Yes, you've correctly diagnosed my stupidity -- that is indeed the empty tautological statement that I'm making". Sheesh.

> > You are the one who raised the "CMBR dipole=0 frame",
>
> Not really....

Yes really. There's no point is lying, your messages are still there for anyone to read. Sheesh.

> So the constancy of their results can be interpreted as tests of local
> Lorentz invariance...

No, since dtau/dT = 1 is also true in terms of Galilean relativity (for example), which does not satisfy Lorentz invariance. The only thing that is supported by observing relativity is the principle of relativity itself, and you haven't even articulated how that is actually done, i.e., establishing the proportionality of characteristic lapses of proper time for multiple physical processes (non-circular). And, again, none of this supports your erroneous statements at issue, i.e., your denial that dtau/dt = sqrt(1 - v^2/c^2) for any standard clock moving at speed v=dxdt in terms of inertial coordinates x,t.

> Please explain how one can compare the tick rates of relatively-moving clocks without signals.
In the usual way: Clock rates dtau/dt are defined in terms of coordinate systems x,t. Inertial coordinate systems (in particular) are defined by the requirement that inertia is homogeneous and isotropic in terms of those coordinates, and it follows that such coordinates agree with a grid of standard rulers and clocks at rest and inertially synchronized in any given frame. Using such a grid we can note the positions and times of any clock in any location and state of motion. We can use any mapping we like between the events of the worldlines of separate clocks. The relations between these entities are objective facts, regardless of what "signaling" may or may not be occurring.

> Sure, but to MEASURE that for a clock moving relative to those coordinates
> requires signals.

Again, for a standard clock moving at speed v = dx/dt in terms of an inertial coordinate system x,t, the rate of the clock is dtau/dt = sqrt(1 - v^2/c^2), regardless of whether you measure it or not, and regrdless of whether there are any signals present or not. (Switching the caps from the word "signals" to the word "measure" is still just as crackpotish.) The physical significance of this can be seen by considering a grid of standard rulers with clocks (inertially synchronized) at each node, and the readings of a clock moving through this grid can be recorded and directly compared with the recorded readings of the coinciding clocks of the grid as it passed them. Again, denying the simple and plain facts of special relativity by mindlessly repeating your meaningless fantasy about "signals" is just silly.

> Sure. But comparisons of clock tick rates are more complicated than just
> "time dilation".

All aspects of the spatio-temporal relations are entailed by the descriptions of events in terms of whatever system of coordinates we have chosen to use. Without a system of coordinates, we can't characterize the spatio-temporal relations between events at all, and with a system of coordinates the events have objective characteristics and relations, independent of "signaling".

Again, in terms of any system of coordinates x,t the time tau of a standard clock is dtau/dt = sqrt[g_mn dx^m dx^n]/dt where t =x^0. Note that the word "signals" (with our without caps) does not appear in that sentence. These are objective verifiable facts, and they apply to any number of clocks and other objects, and they entail any physically meaningful comparisons.

On Wednesday, July 14, 2021 at 11:44:48 AM UTC-7, tjrob137 wrote:
> Atomic spectroscopy is performed in a lab on earth, measuring emissions
> from atoms approximately at rest in that lab.

This confirms that you're just saying dtau/dT = 1 in terms of local inertial coordinates X,T in which the clock is at rest. Duh. This is true in Galilean relativity as well. That does not express the objective fact of relativistic time dilation. At the level of your thought, it is nothing but an empty tautology. The relevant fact is that, letting x,t denote any given system of local inertial coordinates, and letting tau denote the proper time of an object moving with speed v=dx/dt, we have dtau/dt = sqrt(1 - v^2/c^2), so the rate does indeed vary with speed as predicted by special relativity. Spectroscopy is routinely performed by astronomers to examine the chemical compositions of distant astronomical objects, and the results are perfectly consistent with the objective facts of time dilation -- facts which you weirdly insist on denying.

> Please explain how one can compare the tick rates of relatively-moving clocks without signals.

Again, clock rates are defined in terms of coordinate systems, and the rates of clocks in terms of various systems of coordinates have objective values, regardless of whether they are measured, and regardless of the presence or absence of "signals". Specifically, the proper time of an object moving with speed v=dx/dt in inertial coordinates x,t is dtau/dt = sqrt(1 - v^2/c^2). Note that the words 'measure' and 'signals' do not appear in that statement of objective fact. Special relativity is not like CI quantum mechanics with a measurement postulate, according to which the act of a measurement reduces the superpositional wave function onto some basis. Special relativity is a classical theory in that sense.

> Sure, but to MEASURE that for a clock moving relative to those coordinates requires signals.

It does not involve signals in any way that supports your denial of the objective facts of time dilation. We have a grid of standard rulers with clocks (inertially synchronized) at each node, and the readings of a test clock moving through this grid can be recorded and directly compared with the recorded readings of the coinciding clocks of the grid as it passed them. This involves only the recognition of coinciding events.

The issue here is that you claim relativistic effects such as time dilation and length contraction are not "real", and your error has been explained by every competent physicist from Einstein to the present day. Fundamentally your misconception is based on your failure to recognize that the physical significance of Lorentz invariance is not based on passive transformations, it is based on active transformations. Until you understand this you'll never be able to understand special relativity.

> Sure. But comparisons of clock tick rates are more complicated than just "time dilation".

All aspects of the spatio-temporal relations are entailed by the descriptions of events in terms of whatever system of coordinates we have chosen to use. Without a system of coordinates, we can't characterize the spatio-temporal relations between events at all, and with a system of coordinates the events have objective characteristics and relations, independent of "signaling". Again, in terms of any system of coordinates x,t the time tau of a standard clock is dtau/dt = sqrt[g_mn dx^m dx^n]/dt where t =x^0. Note that the word "signals" (with our without caps) does not appear in that sentence. These are objective verifiable facts, and they apply to any number of clocks and other objects, and they account for all physically meaningful comparisons.

Arthur Adler wrote:

> On Wednesday, July 14, 2021 at 11:44:48 AM UTC-7, tjrob137 wrote:
>> Atomic spectroscopy is performed in a lab on earth, measuring emissions
>> from atoms approximately at rest in that lab.
>
> This confirms that you're just saying dtau/dT = 1 in terms of local
> inertial coordinates X,T in which the clock is at rest. Duh.

you may duh all you want, but you can't read. He is saying he is
performing a measurement. You relativists always get in trouble with
measurements.

"Arthur Adler" wrote in message
news:3b9c5780-0e93-4f94-8ab4-94184f44e11cn@googlegroups.com...

On Friday, July 9, 2021 at 12:47:24 PM UTC-7, Kevin Aylward wrote:
> >Special relativity is based on the premise that all the equations of
> >physics
> (whether they be deterministic or not) take the same homogeneous and
> isotropic >form in terms of every local system of inertia-based
> coordinates.
>
> That's Covariance. All equations can be put in General Covariance
> form. Its a principle of mathematics not physics.

>No, you're just mindlessly rehearsing the well-known comments related to
>expressing the laws of physics in generally covariant form, e.g., as tensor
>equations, which is unrelated to the special principle of relativity

Ho hummm.....repeating back what I just explained to you doesn't get you
any brownie points. Hint:

https://www.kevinaylward.co.uk/gr/postulate1/postulate1.html

>. The principle of relativity (Galileo) is a meaningful physical principle

Sure, the principle (POR) has meaning.

>resting on the distinguished class of coordinate systems, called the
>inertial coordinates,

Nope. Coordinate systems have no physical content whatsoever. Period. They
are simply labels on events. Events don't depend on coordinates. "inertial
coordinates" is, technically, a meaningless statement. Coordinates systems
are abstractions, they have no physical properties at all.

You are confusing virtual coordinate systems that *may* be locked to a real
physical frame.

For example, one can have a rotating coordinate system describing an
inertial frame, or static coordinate systems describing an accelerating
frame.

Coordinate systems and physical reference frames are not the same. Again, I
refer you to:

J.D. Norton

http://www.pitt.edu/~jdnorton/papers/decades.pdf

> in terms of which the equations of Newtonian mechanics hold good in the
> low speed limit. Special relativity asserts that these special coordinate
> systems are related by >Lorentz transformations.

Nope. You are way confused. SR asserts that they are special reference
frames that may be conveniently described by using a coordinate system
locked to that reference frame.

>This is a crucial dynamical physical principle underlying special
>relativity (not to mention Newtonian mechanics), and you must not conflate
>this in your mind with the >mathematical formalism of general covariance.

As soon as you said "inertial coordinate system", you had lost it.

>Again, the local Lorentz invariance of all physical laws does not imply
>that the laws of physics are (or are not) deterministic.

Oh yes they do. Its a derived result. As I noted, The SR *model* inherently
implies a block universe. Its a well known property of SR, yet swept under
the carpet, for example:

Roger Penrose "The Emperor's New Mind" p.393:

"...There can be no uncertain future. The whole of space-time must be fixed,
without any scope for uncertainty. Indeed, this seems to have been
Einstein's own conclusion (cf. Paris 1982 p.444). Moreover there is no flow
of time at all. We have just "space-time" - and no scope at all for a future
whose domain is being inexorably encroached upon by a determined past...!
(The reader may be wondering what is the role of the uncertainties of
quantum Mechanics in all of this. I will return to the questions raised by
Quantum Mechanics later in the next chapter..."

Somewhat unfortunate that you are unaware of this basic, well known
principle that SR must be strictly deterministic. Thus, it fundamentally
contradicts QM

>(Naturally the non-relativistic Schrodinger equation is, well,
>non-relativistic, but relativistic quantum mechanics, including the Dirac
>equation, quantum field theory, Klein >Gordon equation, etc, is
>relativistic.)

But not relevant to the above point.

You appear to be waffling on matters you have little idea on. Let me know
where the minus sign is lost in my derivation of the Riemann Curvature
Tensor and I might change my view on this.

https://www.kevinaylward.co.uk/gr/riemann/riemann.html

-- Kevin Aylward
http://www.kevinaylward.co.uk/gr/index.html
http://www.kevinaylward.co.uk/qm/index.html

"Arthur Adler" wrote in message
news:a5199219-c800-4a5b-931b-8f391ed7792bn@googlegroups.com...

>>It does not involve signals in any way that supports your denial of the
>>objective facts of time dilation. We have a grid of standard rulers with
>>clocks (inertially synchronized) >at >each node, and the readings of a
>>test clock moving through this grid can be recorded and directly compared
>>with the recorded readings of the coinciding clocks of the grid >as it
>> >passed them. This involves only the recognition of coinciding events.

>The issue here is that you claim relativistic effects such as time dilation
>and length contraction are not "real", and your error has been explained by
>every competent
>physicist from Einstein to the present day. Fundamentally your
>misconception is based on your failure to recognize that the physical
>significance of Lorentz invariance is not >based on passive
>transformations, it is based on active transformations. Until you
>understand this you'll never be able to understand special relativity.

You seem quite confused. *Physical* "length contraction" is a feature of LET
(Lorentz Ether Theory) not SR. The "length" of an object in SR rotates in
"space-time". Length is an invariant in SR. Time "dilation" is, essentially
an "optical illusion". All real physical effects such as reuniting clocks
are due to differences in their paths in space time, that is, a result of
differences in non inertial motion. Time dilation *cannot* be physically
real because *both* observers see the *other* dilated, much like both
observers viewing the other through a magnifying glass see the other larger.
Its nonsensical for both observers to be physically larger. Until you
understand this you'll never be able to understand special relativity, or
why alternatives might make better sense.

-- Kevin Aylward
http://www.kevinaylward.co.uk/gr/index.html
http://www.kevinaylward.co.uk/qm/index.html

Kevin Aylward <kevinRemoveandReplaceATkevinaylward.co.uk> wrote:
> "Arthur Adler" wrote in message
> news:a5199219-c800-4a5b-931b-8f391ed7792bn@googlegroups.com...
>
>
>
>>> It does not involve signals in any way that supports your denial of the
>>> objective facts of time dilation. We have a grid of standard rulers with
>>> clocks (inertially synchronized) >at >each node, and the readings of a
>>> test clock moving through this grid can be recorded and directly compared
>>> with the recorded readings of the coinciding clocks of the grid >as it
>>>> passed them. This involves only the recognition of coinciding events.
>
>> The issue here is that you claim relativistic effects such as time dilation
>> and length contraction are not "real", and your error has been explained by
>> every competent
>> physicist from Einstein to the present day. Fundamentally your
>> misconception is based on your failure to recognize that the physical
>> significance of Lorentz invariance is not >based on passive
>> transformations, it is based on active transformations. Until you
>> understand this you'll never be able to understand special relativity.
>
> You seem quite confused. *Physical* "length contraction" is a feature of LET
> (Lorentz Ether Theory) not SR. The "length" of an object in SR rotates in
> "space-time". Length is an invariant in SR. Time "dilation" is, essentially
> an "optical illusion". All real physical effects such as reuniting clocks
> are due to differences in their paths in space time, that is, a result of
> differences in non inertial motion. Time dilation *cannot* be physically
> real because *both* observers see the *other* dilated, much like both
> observers viewing the other through a magnifying glass see the other larger.
> Its nonsensical for both observers to be physically larger.

This is a common misunderstanding and is associated with a mental claim
that “physical length” is an innate property of an object. Then it follows
from that claim that it is impossible for both observers to be “physically
larger”.

However in relativity the claim is that length is NOT an innate property of
an object. (There is a property called “proper length” which is no more
complicated than the projection of any coordinate length onto the object’s
rest frame, but there’s no real reason to think of this as any more
“physical” than any other.) In relativity, there is a recognition that
length has an *operational* definition, which usually goes something like
the distance between location markers at extrema of the object where the
location markers are place *simultaneously*. That last word then becomes
essential, because it’s obvious that simultaneous placement of markers is a
frame-dependent specification. Because length is so operationally defined,
there *is no* sense in which innateness applies, and the mental claim is
just misplaced. Length is no more an innate property of an object than
velocity or kinetic energy would be. Just a moment’s thought tells you that
for two otherwise identical objects at rest in different reference frames,
each other sees the other’s kinetic energy as larger — and there is
absolutely no logical contradiction in that statement.

> Until you
> understand this you'll never be able to understand special relativity, or
> why alternatives might make better sense.
>
>
> -- Kevin Aylward
> http://www.kevinaylward.co.uk/gr/index.html
> http://www.kevinaylward.co.uk/qm/index.html
>
>

--
Odd Bodkin -- maker of fine toys, tools, tables

On Thursday, July 15, 2021 at 11:30:13 AM UTC-7, Kevin Aylward wrote:
> > Special relativity is based on the premise that all the equations of physics
> > (whether they be deterministic or not) take the same homogeneous and
> > isotropic form in terms of every local system of inertia-based coordinates.
>
> That's Covariance. All equations can be put in General Covariance
> form. Its a principle of mathematics not physics.

No, you're conflating the issue of general covariance (i.e., expressing physical laws as tensor equations) with the principle of special relativity and Lorentz invariance, which asserts that all the equations of physics take their simple homogeneous and isotropic form in terms of a distinguished class of coordinate systems, called inertial coordinates, which are related by Lorentz transformations. This has nothing whatsoever to do with the mathematical concept of general covariance.

> Nope. Coordinate systems have no physical content whatsoever. Period.

Again, there is a distinguished class of coordinate systems, called inertial or inertia-based coordinates, in terms of which the equations of physics uniquely take their simple homogeneous and isotropic form. This is a crucially significant physical fact. Until you understand this, you will understand nothing about special relativity.

> > Again, the local Lorentz invariance of all physical laws does not imply
> >that the laws of physics are (or are not) deterministic.
>
> Oh yes they do.

Nope, Lorentz invariance merely asserts that the laws of physics -- whatever they may be (e.g., deterministic or not) -- take the same form in terms of any system of inertia-based coordinates. For example, the laws of quantum electrodynamics and Dirac's equation and the relativistic Schrodinger equation of relativistic quantum mechanics are all explicitly Lorentz invariant. These are all consistent with the Heisenberg uncertainty relation.

> Roger Penrose "The Emperor's New Mind" p.393:

Appeals to authority are pointless, but I'll just mention that you must have a different edition, since that quote is on page 304 of the original 1989 edition, but note that Penrose admits later in the same book that quantum mechanics does not conflict with special relativity is any observable way, and, more importantly, by the time he wrote his "Road to Reality" in 2002 he had realized (prompted by criticisms) that that passage from Emperor's, along with the whole Andromeda paradox stuff, was all nonsense, and he was embarrassed, which is why you find no trace of that nonsense in Road. He basically fell prey to the Fontenot/Harnagel Fallacy while writing Emperors, but fortunately pulled out of it.

> [quoting Penrose Emperror] Indeed, this seems to have been Einstein's own
> conclusion (cf. Paris 1982 p.444).

That's a bogus reference, since Pais only recounts the fact that Einstein drafted a paper in which he argued for hidden variables, hoping to evade Heisenberg's uncertainty relation, but before publication Einstein realized the argument was fallacious and withdrew the paper. As all serious scholars know, Einstein explained very carefully to Pauli and Born that his mature objection to quantum mechanics was *not* over determinism, and he (Einstein) did not maintain that determinism is required (and he forever lamented the too quotable flippant dice comment), but rather the apparently non-locality. But we now know that quantum mechanics is perfectly consistent with the locality of Lorentz invariance, i.e., spacelike observables commute.

> this basic, well known principle that SR must be strictly deterministic. Thus, it fundamentally
> contradicts QM

To the contrary, what you have in your brain is the well-known sophomoric misconception, and in fact special relativity is perfectly compatible with quantum field theory, and indeed Lorentz invariance is one of the cornerstones of QFT. Of course, it goes without saying the relativity is incompatible with non-relativistic QM, but that's why relativistic QM was invented. Duh.

> ... not relevant to the above point.

Huh? You claim that QFT is incompatible with special relativity, and I point out that you are mistaken, since QFT is founded on local Lorentz invariance (special relativity), and you say that's not relevant to your point? What is wrong with you?

> Let me know where the minus sign is lost in my derivation of the Riemann
> Curvature Tensor...

Derivation of the curvature tensor? The curvature tensor is derived, it is defined as the tensor that encodes all the Gaussian curvatures of a manifold at any given point. The geodesic paths satisfy the geodesic equation, which involves the Christoffel symbols, which are defined in terms of the metric coefficients, which must satisfy the field equations. What part of this don't you understand?

> *Physical* "length contraction" is a feature of LET (Lorentz Ether Theory) not SR.

No, LET is nothing but an interpretation of special relativity, with a peculiar semantic affectation. They are the same physical theory, the only semantic difference being that LET declares one particular system of inertial coordinates as the "true" one, but this can be *any* system, and the designation "true" has no physical significance.

> Time dilation *cannot* be physically real because *both* observers see the *other* dilated...

Your conclusion does not follow from your premise. In both SR and LET, in terms of any system of inertial coordinates x,t the elapsed time tau on an ideal clock moving at speed v=dx/dt advances at the rate dtau/dt = sqrt(1-v^2/c^2). This is a verifiable objective fact. If your definition of "physically real" refers to something other than verifiable objective facts, then you are using non-standard terminology.

On Friday, 16 July 2021 at 04:13:41 UTC+2, Arthur Adler wrote:

> No, LET is nothing but an interpretation of special relativity, with a peculiar semantic affectation. They are the same physical theory, the only semantic difference being that LET declares one particular system of inertial coordinates as the "true" one, but this can be *any* system, and the designation "true" has no physical significance.

Oh, yes, poor idiot, it has. Surprise! Check GPS. The clocks
are adjusted - to "true" coordinates.

On Thursday, July 15, 2021 at 9:13:41 PM UTC-5, Arthur Adler wrote:

> No, LET is nothing but an interpretation of special relativity, with a peculiar semantic affectation. They are the same physical theory, the only semantic difference being that LET declares one particular system of inertial coordinates as the "true" one, but this can be *any* system, and the designation "true" has no physical significance.

No, although LET and SR share the same math, they are most decidedly
not the same theory.

LET was, very specifically, a theory of electromagnetism that assumes
that electromagnetic phenomena are propagated via a motionless aether
of peculiar properties.

The "final" version of LET would be the theory as it existed approximately
1905 ± 1 year. Lorentz and Poincaré did not attempt to apply LET to
gravitational phenomena, and of course, the strong and weak forces
where unknown. LET considers light to be a wave phenomenon, and gives
no explanation of what use an undetectable aether would be in facilitating
the propagation of quanta.

Yet the equations of LET apparently apply not merely to EM phenomena,
but to gravitation and the strong and weak forces. This leads to various
unanswered questions, including, why does c represent the same upper
limit of signal propagation for these vastly different forces?

A priori, it might seem that each of the four fundamental forces of nature
requires its own aether. If that were so, what fine-tunes the four aethers
so that waves are propagated with the same speed in each?

Even if, somehow or other, the forces of nature shared the same aether,
that -still- does not explain the coincidence of signal propagation speeds.
Consider seismic waves: P, S, and surface waves (Love and Rayleigh)
all travel at different speeds through the same Earth.

There are other issues...
Current attempts to treat LET as some sort of "neo-Lorentzian"
interpretation of special relativity do not ascribe any purpose for the
undetectable aether, and the principle of relativity arises as a
mathematical artifact rather than as a fundamental principle.

All of these issues are resolved in special relativity.

On Friday, July 16, 2021 at 2:08:14 AM UTC-7, prokaryotic.c...@gmail.com wrote:
> > LET is nothing but an interpretation of special relativity, with a peculiar semantic affectation.
> > They are the same physical theory, the only semantic difference being that LET declares one
> > particular system of inertial coordinates as the "true" one, but this can be *any* system, and
> > the designation "true" has no physical significance.
>
> No, although LET and SR share the same math, they are most decidedly
> not the same theory. LET was, very specifically, a theory of electromagnetism...

I'm not referring to what LET *was* at various stages of its development, I'm referring to LET in its final form as triply-amended in the final version, as summarized in Lorentz's 1909, and as it still exists today. This is essentially the theory as presented in Lorentz's 1904, with corrections of the charge density, etc., by Poincare. This very explicitly asserts that all the laws of physics (explicitly including, per Lorentz himself, whatever forces are responsible for maintaining the structure of atoms and sub-atomic particles), not just electromagnetism, are what we call Lorentz invariant. It is entirely equivalent to, and indistinguishable from, conventional special relativity, differing only semantically. This is very well known and not controversial in the scholarly literature.

> LET considers light to be a wave phenomenon...

No, the final (and current) version of LET is not committed to any particular model of matter or light, just as special relativity is not. As you yourself admitted, they share "the same math", and the same mapping between physical variables and the terms of the math, so they are the same theory, i.e., they are empirically identical, differing only in metaphysical interpretation and semantics.

> Yet the equations of LET apparently apply not merely to EM phenomena,
> but to gravitation and the strong and weak forces.

Again, both Lorentz and Einstein postulate this, i.e., all the laws of physics are Lorentz invariant. Back around 1900 some people thought everything might ultimately be reducible to electromagnetism, but already in 1904 both Lorentz and Poincare realized that the forces involved in maintaining the structure of elementary particles need not be electromagnetic, but it is necessary to suppose that, whatever those forces are, they are Lorentz invariant, which of course is what Einstein posited as well. You can read about this in any good book on the foundations of relativity. This is not controversial.

> Current attempts to treat LET as some sort of "neo-Lorentzian" interpretation of
> special relativity do not ascribe any purpose for the undetectable aether....

Irrelevant. Everyone knows that LET (aka the Lorentzian interpretation of special relativity) is hypocritical and pointless -- unless some violation of Lorentz invariance was ever found. Lorentz himself made it clear that the "ether" had not identifiable properties or dynamics, but was simply an opportunistic designation of one particular system of inertial coordinates to be regarded as the "true" coordinates, because he regarded that as more intelligible, not because of any purported Maxwellian cog and flywheel account of ether dynamics.

> All of these issues are resolved in special relativity.

Well, the conventional interpretation of special relativity dispenses with the superfluous concept of an ether with a definite state of motion, and simply treats the symmetry between all inertial coordinate systems as the fundamental fact. It dispenses with the hypocrisy inherent in the Lorentzian interpretation. But these are interpretational issues, not scientific issues. From an empirical standpoint, these are just two different interpretations of the same theory. Again, none of this is controversial. I urge you to acquaint yourself with the scholarly literature on this subject before you attempt to lecture on it.

On 7/16/21 4:53 AM, Arthur Adler wrote:
> both Lorentz and Einstein postulate this, i.e., all the laws of
> physics are Lorentz invariant.

This is just plain not true. You propose revisionist history -- read
Lorentz's 1904 paper to see how he actually derived the equations of LET
in a frame moving wrt the ether frame:
1. assume there is a unique ether rest frame
2. apply a Galilean transform to the moving frame
3. perform a change of variables that he simply made up,
without any justification whatsoever (except that it
gives the desired result: Maxwell's equations look
the same as in the ether frame).
4. the result is the Lorentz transform, JUST for ether
frame to moving frame, and the Maxwell's equations
in the moving coordinates. He didn't actually display
the Lorentz transform in 1904 (he did later). He made
a mistake in the transform of charge density,
corrected by Poincare' in 1905. AFAIK Lorentz never
discussed the inverse of the transform he derived, nor
using it between frames other than the ether frame to
a moving frame.
There is no invariance there at all; indeed #1 precludes it. Any
derivation based on the PoR, or similar concepts, is about SR, not LET
-- LET does not obey the PoR (#1 prevents it).

The notion of Lorentz invariance, and indeed any invariance of this
kind, was not part of physics in 1904-5 [@]. Einstein was groping toward
it -- his PoR (1905) is an invariance principle, but he did not
generalize it until after 1911 or so on his path to GR.

[@] If such invariance had been common in physics then,
SR would already have been discovered, because it is
clear that the Maxwell's equations are not Galilean
invariant. It was "in the air" in 1904-5, but only
Einstein actually adopted it (in his PoR). Poincare'
proved the ME are Lorentz invariant, and coined the
phrase, but at the time neither he nor Lorentz bought
into the modern interpretation given by Einstein (i.e.
that the "local time and local coordinates" of LET are
the ones real experimenters use). [That's a different
meaning of "local" than we use today with GR.]

[Mathematicians, of course, had known all about invariance
and its importance in differential equations, for many
years (Sophus Lie, 1890s). It did not really become
important in physics until Noether's theorems (1918).]

LET is not the same theory as SR, because it does not include Lorentz
invariance while SR does. Basic differences:
* In LET, moving atoms physically get shorter along their
direction of motion (relative to the ether)
* In LET, clocks physically slow down when moving relative to
the ether.
* In SR, neither of these affect properties of atoms or clocks,
they only apply to measurements made from relatively-moving
frames, and the direction is of the relative motion, not
relative to any ether.
* LET is tied specifically to Maxwell's electrodynamics.
* SR applies to all physical theories that model how the states
of systems undergo change. Its Lorentz invariance is an
essential foundation of all theories of physics we have today.
It is "happenstance" that experimental measurements in LET are predicted
to be the same as those predicted by SR (this of course applies only in
their mutual domain).

[Of course there is no happenstance in mathematics. The
transform that Lorentz crafted his derivation to yield
is a representation of the Lorentz group.]

> You can read about this in any good book on the foundations of
> relativity.

Please give a reference to one that mentions LET at all. Not just
Lorentz, but his actual ether theory.

> Everyone knows that LET [...]

This is also not true. It might be true around here (probably not), but
almost no physicists have ever heard of LET. In 2006 I gave a colloquium
at Fermilab [#] on the experimental basis of SR. In Q&A afterward I
asked people to raise their hands if they had ever heard of Lorentz
Ether Theory [%]. Nobody raised their hand, and the question was greeted
with "What???".

[#] Fermilab is the premier particle physics laboratory
in the U.S.A. Particle physicists use SR in practically
everything they do. I have worked there on and off for
over four decades.

[%] I had heard of LET in this newsgroup, and have
posted about it and related "theories equivalent to SR":
https://groups.google.com/g/sci.physics.relativity/c/2uSdJXbUiaY/m/111CgF54a_QJ?pli=1
(Google Groups mangles text by scrunching whitespace.)

Tom Roberts

On Friday, July 16, 2021 at 4:33:49 PM UTC-7, tjrob137 wrote:
> > both Lorentz and Einstein postulate this, i.e., all the laws of
> > physics are Lorentz invariant.
> This is just plain not true.

You're mistaken. Both the Lorentzian and the Einsteinian interpretation of special relativity consider the class of coordinate systems related by Lorentz transformations, and both of them assert that *all* the laws of physics -- not just electromagnetism -- take their simple homogeneous and isotropic form in terms of those systems. This is the content of local Lorentz invariance. The empirical equivalence between the two interpretations is well known.

> Read Lorentz's 1904 paper...

It is obvious from your sophomoric comments that you have not read it with any comprehension. I think your best hope for understanding it is to find a good secondary source that spells things out in simple terms.

> to see how he actually derived the equations of LET

The issue is not how equations were "derived", it is about how he went on to use those equations and what physical meaning he asserted for them, and for this you would need to be able to read Lorentz with comprehension, paying special attention to the clearly identified sequence of assumptions that, collectively, amount to the assumption of complete Lorentz invariance. This is all quite well known.

> There is no invariance there at all...

Again, Lorentz invariance refers to the systems of coordinates related by Lorentz transformations, and the set of assumptions clearly delineated in Lorentz's 1904 that collectively amount to the assumption of complete Lorentz invariance. The fact that he gives verbal primacy to one particular system of inertial coordinates is purely semantic, since it has no physical significance in his theory.

> indeed #1 precludes it.

Not at all, your #1 is purely a semantic assertion with no physical content, since Lorentz explains that all the laws of physics take their simple homogeneous and isotropic form in terms of every one of the systems of coordinates related by Lorentz transformations. The fact that he (arbitrarily and hypocritically) identifies one particular system as the "true" one is of no physical significance to the theory, and he came to understand this eventually.

> > Everyone knows that LET [...]
> almost no physicists have ever heard of LET.

Most worker-bees in physics-related activities have little interest in, or knowledge of, or aptitude for, the foundational aspects of the subject. When I say "everyone" I obviously mean every competent scholar who is even remotely cognizant of the foundations of physics.

> * In LET, moving atoms physically get shorter along their
> direction of motion (relative to the ether)

Same for both interpretations, i.e., in terms of any system of coordinates x,t in which the equations of physics take their simple form (related by Lorentz transformations), the spatial extent dx of an object moving at speed v at a given t is shorter by the factor sqrt(1-v^2/c^2).

> * In LET, clocks physically slow down when moving relative to
> the ether.

Same for both interpretations, i.e., in terms of any system of coordinates x,t in which the equations of physics take their simple form (related by Lorentz transformations), the rate dtau/dt of elapsed proper time of an ideal clock moving at speed v is slow by the factor sqrt(1-v^2/c^2).

> * In SR, neither of these affect properties of atoms or clocks,

False, the above statements refer to perfectly well-defined properties, noting that in order to understand this one must have the mental capacity to grasp the distinction between passive and active transformations -- which you do not.

> * LET is tied specifically to Maxwell's electrodynamics.

No, you need to read Lorentz's 1904 paper, paying attention to the non-electromagnetic assertions of Lorentz invariance. You should also try to focus your brain on the fact that if what you are saying were true, LET and SR would be easily distinguishable empirically. Think.

> * SR applies to all physical theories that model how the states
> of systems undergo change.

Same for both interpretations... see above.

> I had heard of LET in this newsgroup...

Yes, it appears from the google archive that you learned about it from people here, and that you initially denied that SR and LET were empirically indistinguishable, and your denial of this well-known fact continued for a very long time, until finally you stumbled into a book by Zhang, and then from this authority you switched your position, and have apparently been "dining out" on this minor and grudging epiphany ever since... until now.

> and have posted about it and related "theories equivalent to SR":

Right, once you were finally convinced that you were wrong in your denial of the well-known empirical equivalence of SR and LET, you began to preach that equivalence... which makes it all the more strange that you've now slid back into denying it. I just found some posts of yours from over 20 years ago in which you proudly rehearse your new-found knowledge that LET and SR are really just different interpretations of the same theory, and they differ only semantically. .. a realization that you were forced to accept only grudgingly. But now, somehow, you've lost that lesson, and have reverted back to your original denialism. Strange.

Again, the modern form of "LET" is nothing but special relativity combined with the semantic commitment to label one particular system of inertial coordinates as the "true" one, and the others as "apparent", but this designation is arbitrary and has no physical significance in the theory.

On Saturday, 17 July 2021 at 01:33:49 UTC+2, tjrob137 wrote:

> LET is not the same theory as SR, because it does not include Lorentz
> invariance while SR does.

That makes it consistent with the reality while your Shit
is obviously not.

On Friday, July 16, 2021 at 11:23:50 PM UTC-5, Arthur Adler wrote:

> You're mistaken. Both the Lorentzian and the Einsteinian interpretation of special relativity consider the class of coordinate systems related by Lorentz transformations, and both of them assert that *all* the laws of physics -- not just electromagnetism -- take their simple homogeneous and isotropic form in terms of those systems. This is the content of local Lorentz invariance. The empirical equivalence between the two interpretations is well known.

Which "Lorentzian" interpretation of special relativity do you refer to?
Lorentz' 1904 paper on "Weiterbildung der Mawellschen Theorie"
and his subsequent paper "Electromagnetic Phenomena in a System
Moving with Any Velocity Less than that of Light" presented an
electromagnetic world view. The papers discussed possible
resolution ​of the MMX experiment (his contraction hypothesis), and
of the turning couple experiment of Trouton and Noble (an additional
elastic force in the suspension that transforms like the EM force).
The negative birefringence experiments of Rayleigh and of Brace
presented a special problem, because Lorentz had previously
expected that strains originating from the deformations implied by
his contraction hypothesis should cause moving isotropic bodies
to exhibit double refraction.

In an attempt to explain these results, Lorentz added the additional
conjecture of "electromagnetic mass" and proposed means whereby,
with "the dimensions of the individual electrons becom[ing] changed
by translation," the theory of the optics and electrodynamics of moving
bodies could be revised to accommodate Rayleigh's results.

He wrote, "Our assumption about the contraction of the electrons
cannot in itself be pronounced to be either plausible or inadmissible.
What we know about the nature of electrons is very little and the only
means of pushing our way farther will be to test such hypotheses
as I have here made."

"Lorentz ether theory" pre-Einstein was very specifically NOT a theory
based on local Lorentz invariance.

"Lorentz ether theory" pre-Einstein was a theory of the DEFORMABLE
ELECTRON.

You claim that by 1909, Lorentz' awkward piling on of hypothesis
upon hypothesis morphed into a elegant statement that "all the laws
of physics are Lorentz invariant." Against this claim of yours, I note
that even -Einstein- did not fully understand SR as being a theory of
Lorentz invariance until several years later than that. And Poincare,
the other major contributor to what is considered to be "LET",
strongly considered the possibility that the principle of relativity
might not represent a fundamental principle. To the end of his life,
Poincare never abandoned the aether hypothesis.
https://en.wikisource.org/wiki/The_New_Mechanics

On Friday, July 16, 2021 at 11:48:50 PM UTC-7, prokaryotic.c...@gmail.com wrote:
> > Both the Lorentzian and the Einsteinian interpretation of special relativity consider the class of coordinate systems related by Lorentz transformations, and both of them assert that *all* the laws of physics -- not just electromagnetism -- take their simple homogeneous and isotropic form in terms of those systems. This is the content of local Lorentz invariance. The empirical equivalence between the two interpretations is well known.
>
> Which "Lorentzian" interpretation of special relativity do you refer to?

There's only one, entailed by the theory described initially in Lorentz's 1904, with some imperfections corrected by Poincare in 1905, and gradually clarified and summarized in Lorentz's later writings, notably his "The Theory of Electrons" in 1909 and re-issued with some clarifications in 1915... as well as in private correspondence.

> In an attempt to explain these results, Lorentz added the additional
> conjecture of "electromagnetic mass"...

You didn't read correctly. Electromagnetic mass is not a conjecture, it is a feature of Maxwellian electrodynamics (and hence is Lorentz invariant), but the necessary assumption made by Lorentz was that *either* all mass is ultimately electromagnetic in origin *or* if not, that all mass nevertheless transforms like electromagnetic mass, i.e., that it is what we call Lorentz invariant. Likewise he was led to assume that all physical forces, including whatever forces are responsible for the structure of electrons, etc., are either electromagnetic *or* if not, that they transform like electromagnetic forces, i.e., they are what we call Lorentz invariant. So, by this set of explicit assumptions he (and Poincare) effectively postulated Lorentz invariance of all physical phenomena... which of course is what Einstein did as well (somewhat more succinctly).

> "Lorentz ether theory" pre-Einstein was very specifically NOT a theory
> based on local Lorentz invariance.

You are mistaken, as explained above.

> "Lorentz ether theory" pre-Einstein was a theory of the DEFORMABLE
> ELECTRON.

Your misconception about this is the same as Tom's, and was explained in the other message. Again, there is no difference between the shapes of objects or the rates of clocks in motion in terms of any given system of coordinates in either interpretation, because the interpretational differences are mod'ed out by expressing things in operational terms of inertial coordinate systems.

> You claim that by 1909, Lorentz' awkward piling on of hypothesis
> upon hypothesis morphed into a elegant statement that "all the laws
> of physics are Lorentz invariant."

I make no such claim. I point out that the union of Lorentz's principles entails Lorentz invariance of all physical laws, just as does the union of Einstein's principles, and it doesn't operationally matter whether these principles are expressed elegantly (which is a subjective criterion in any case).

> Even -Einstein- did not fully understand SR as being a theory of Lorentz invariance
> until several years later than that.

Sure, Einstein didn't even have mass-energy equivalence explicitly in the June 1905 paper, and it is obviously true that the thinking of all these individuals continued to evolve over several years, and even in the 1920's Lorentz and Einstein were still corresponding about the comparative merits of their respective interpretations. But neither of them disputed that they were just different interpretations of the same theory.

Again, the empirical equivalence of the conventional interpretation and the Lorentzian interpretation of special relativity is well known, and you can read about it in any good book on the foundations of relativity. If you want to claim that they are different theories, i.e., that they make different predictions (at least in principle), then go ahead and name some physical phenomena for which you think they give different predictions. Hint: You cant.

On Saturday, 17 July 2021 at 09:50:43 UTC+2, Arthur Adler wrote:

> Again, the empirical equivalence of the conventional interpretation and the Lorentzian interpretation of special relativity is well known, and you can read about it in any good book on the foundations of relativity. If you want to claim that they are different theories, i.e., that they make different predictions (at least in principle), then go ahead and name some physical phenomena for which you think they give different predictions. Hint: You cant.

Of course I can, poor idiot. LET predicts GPS clocks, after proper
corections, will indicate t'=t; The Shit predicts them to desynchronize,
for the glory of our Giant Guru.
LET matches the reality and The Shit doesn't.

Maciej Wozniak wrote:

> On Saturday, 17 July 2021 at 09:50:43 UTC+2, Arthur Adler wrote:
>
>> Again, the empirical equivalence of the conventional interpretation and
>> the Lorentzian interpretation of special relativity is well known, and
>> you can read about it in any good book on the foundations of
>> relativity.
>> If you want to claim that they are different theories, i.e., that they
>> make different predictions (at least in principle), then go ahead and
>> name some physical phenomena for which you think they give different
>> predictions. Hint: You cant.
>
> Ơ̷̙̠͇͇̼̯̖̦̌̑̊͗f̴̡̱̣͇̙̹͆́́͘͝͠ c̷̯̬̮̼͆͊͋̆̊͝ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕u̸̲͓̫̙̘͉̾̈̎̇̃̽̍̃͝͝r̸̡̹͚̣͔͍̮̩͌͐͝s̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ I̴̡̛̲͙͖̭͑͛͐ c̷̯̬̮̼͆͊͋̆̊͝à̶̜̲̈́͂̓̎͗̽n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜, p̷̛̻̺̝͂̓̎́̕͝ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕r̸̡̹͚̣͔͍̮̩͌͐͝ i̶̢͑̄̈́̾̾̅̕ḑ̶̙͇̰̗̦̠̽i̶̢͑̄̈́̾̾̅̕ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅ. L̴͈̜͍̟̜̪͌̑͋͛̋̔̊͘E̸͙͖͕͐̔Ṫ̸̡̤̉̐̽ p̷̛̻̺̝͂̓̎́̕͝r̸̡̹͚̣͔͍̮̩͌͐͝e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ḑ̶̙͇̰̗̦̠̽i̶̢͑̄̈́̾̾̅̕c̷̯̬̮̼͆͊͋̆̊͝t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅs̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕ G̸̩̪̳͆̏P̷̟̳̝̩̦͉̳̈́̽͋͝S̴̡͈͎̬͍̥͈̣͑̾͋ c̷̯̬̮̼͆͊͋̆̊͝l̷̡̧̢̙͈͍͈͈̉̄͋̔̉̆͝ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕c̷̯̬̮̼͆͊͋̆̊͝k̸̢̯͍͎͐s̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕, à̶̜̲̈́͂̓̎͗̽f̴̡̱̣͇̙̹͆́́͘͝͠t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅe̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝r̸͌�
�̡̹͚̣͔͍̮̩͐ p̷̛̻̺̝͂̓̎́̕͝r̸̡̹͚̣͔͍̮̩͌͐͝ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕p̷̛̻̺̝͂̓̎́̕͝e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝r̸̡̹͚̣͔͍̮̩͌͐͝
> c̷̯̬̮̼͆͊͋̆̊͝ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕r̸̡̹͚̣͔͍̮̩͌͐͝e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝c̷̯̬̮̼͆͊͋̆̊͝t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅi̶̢͑̄̈́̾̾̅̕ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜s̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕, ẉ̸̣̘͙̍̕i̶̢͑̄̈́̾̾̅̕l̷̡̧̢̙͈͍͈͈̉̄͋̔̉̆͝l̷̡̧̢̙͈͍͈͈̉̄͋̔̉̆͝ i̶̢͑̄̈́̾̾̅̕n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜ḑ̶̙͇̰̗̦̠̽i̶̢͑̄̈́̾̾̅̕c̷̯̬̮̼͆͊͋̆̊͝à̶̜̲̈́͂̓̎͗̽t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅe̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅ'=t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅ; Ṫ̸̡̤̉̐̽h̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ S̴̡͈͎̬͍̥͈̣͑̾͋h̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕i̶̢͑̄̈́̾̾̅̕t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅ p̷̛̻̺̝͂̓̎́̕͝r̸̡̹͚̣͔͍̮̩͌͐͝e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ḑ̶̙͇̰̗̦̠̽i̶̢͑̄̈́̾̾̅̕c̷̯̬̮̼͆͊͋̆̊͝t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅs̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕ t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅh̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕e̵̎̋̂̎�
�̢͕͕̯̱̥͔̅͐̂͝m̷̢͈̣̠̃̔̓́͛͒͂̽ t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅỏ̵̝̫̹̱̲̻̗͉̓͒͘̕
> ḑ̶̙͇̰̗̦̠̽e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝s̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕y̷̢̛̪͈͒̆͝n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜c̷̯̬̮̼͆͊͋̆̊͝h̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕r̸̡̹͚̣͔͍̮̩͌͐͝ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜i̶̢͑̄̈́̾̾̅̕z̶̢̟͉̰̮̺̮̔̀͂͒̏̊̏̅̒̅A̸͕̘̻̠͎͍̾̄̉̈́̐͐̚͝ͅB̶̖̓̎͝C̵̨̨͓͇̹͖͙̘͐̓̆͜͠D̴̜̖̹̹̖̩̗͈̔͆͗͊̾̽͝E̸͙͖͕͐̔F̷̨̻̃͛̑͑̅́̓͒G̸̩̪̳͆̏H̴͎͎̦͒͑̕͠ͅI̴̡̛̲͙͖̭͑͛͐J̶̢̡̳̹͚̬̼̙͖̒͜Ḱ̷̛̝̭̈́̾̏̽̕̚L̴͈̜͍̟̜̪͌̑͋͛̋̔̊͘M̴̡̺̀͗͐͒̃ͅN̵͎̞͙̳̘͕̭̏͋̇̏̈́͘͝͝Ơ̷̙̠͇͇̼̯̖̦̌̑̊͗P̷̟̳̝̩̦͉̳̈́̽͋͝Q̶͕̳̗̦͆̋͐̓͊̇̓̊͝R̷̠͕̼̀́͌S̴̡͈͎̬͍̥͈̣͑̾͋Ṫ̸̡̤̉̐̽U̷̢̱͒̕V̴̜̘̑͑͗͝W̷̢̭̞̺̻̬̝͉̳͈̽͊̈́X̵̨̦̘̫̠͔̟̪̙́͑͆͝Y̶̘̓̔͆̿Z̴̤̜̫̯̥͕̜̝̝̈̀͂̋͘ͅe̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝,
> f̴̡̱̣͇̙̹͆́́͘͝͠ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕r̸̡̹͚̣͔͍̮̩͌͐͝ t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅh̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ g̶͎̲̲͎͍͈̱͔̭̾l̷̡̧̢̙͈͍͈͈̉̄͋̔̉̆͝ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕r̸̡̹͚̣͔͍̮̩͌͐͝y̷̢̛̪͈͒̆͝ ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕f̴̡̱̣͇̙̹͆́́͘͝͠ ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕u̸̲͓̫̙̘͉̾̈̎̇̃̽̍̃͝͝r̸̡̹͚̣͔͍̮̩͌͐͝ G̸̩̪̳͆̏i̶̢͑̄̈́̾̾̅̕à̶̜̲̈́͂̓̎͗̽n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅ G̸̩̪̳͆̏u̸̲͓̫̙̘͉̾̈̎̇̃̽̍̃͝͝r̸̡̹͚̣͔͍̮̩͌͐͝u̸̲͓̫̙̘͉̾̈̎̇̃̽̍̃͝͝.
> L̴͈̜͍̟̜̪͌̑͋͛̋̔̊͘E̸͙͖͕͐̔Ṫ̸̡̤̉̐̽ m̷̢͈̣̠̃̔̓́͛͒͂̽à̶̜̲̈́͂̓̎͗̽t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅc̷̯̬̮̼͆͊͋̆̊͝h̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝s̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕ t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅh̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ r̸̡̹͚̣͔͍̮̩͌͐͝e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝à̶̜̲̈́͂̓̎͗̽l̷̡̧̢̙͈͍͈͈̉̄͋̔̉̆͝i̶̢͑̄̈́̾̾̅̕t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅy̷̢̛̪͈͒̆͝ à̶̜̲̈́͂̓̎͗̽n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜ḑ̶̙͇̰̗̦̠̽ Ṫ̸̡̤̉̐̽h̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝ S̴̡͈͎̬͍̥͈̣͑̾͋h̷͓̗̜͚̤̣͉̦̐̈͊͗͒̓͋̑͆̕i̶̢͑̄̈́̾̾̅̕t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅ ḑ̶̙͇̰̗̦̠̽ỏ̵̝̫̹̱̲̻̗͉̓͒͘̕e̵̢͕͕̯̱̥͔̎̋̂̎͐̅͐̂͝s̸̗͙̤͍̩̤͍͍̝̖̃̐̽̌̕n̸̢͙̯͓̝͔̣͈̓̄̆̀̓̈̾̕͜'t̵̨̺̺̬̝̝̠̣̔͌̍̔̃͗́̚ͅ.

nothing.

On 7/15/21 1:29 PM, Kevin Aylward wrote:
> Coordinate systems have no physical content whatsoever. Period. They
> are simply labels on events. Events don't depend on coordinates.

Yes to all that.

> "inertial coordinates" is, technically, a meaningless statement.

No. Not even close.

Coordinates of an inertial frame are special, in that inertia is
homogeneous and isotropic relative to them, and the laws of physics take
their simplest form when projected onto such coordinates.

> Coordinates systems are abstractions, they have no physical
> properties at all.

Hmmmm. The numbers themselves have no physical properties, but
coordinates on an inertial frame have the properties I just described.

> For example, one can have a rotating coordinate system describing an
> inertial frame,

That is an oxymoron -- you need to learn what these words actually mean.

Hint: an inertial frame is a FRAME, with mutually
orthogonal coordinate axes. No rotating coordinates have
mutually orthogonal axes. Note these are all coordinates
on spacetime, not just space.

> Coordinate systems and physical reference frames are not the same.

You attempt to make a distinction without a difference. In normal usage
among physicists, inertial coordinates and the frame they implement are
synonymous.

Yes, technically there are an infinite number of
coordinate systems on a given inertial frame, differing
by spatial rotations. We ignore this technicality as it
is invariably irrelevant to the discussion.

> *Physical* "length contraction" is a feature of LET (Lorentz Ether
> Theory) not SR.

Yes.

> The "length" of an object in SR rotates in
> "space-time".

Hmmmm. Your words are too ambiguous and imprecise.

When different observers measure the length of a given object, that
object's length does not change and does not "rotate in spacetime";
rather it is the different observers' instruments that are oriented
differently in spacetime.

IOW: objects at rest in different inertial frames are oriented
differently in spacetime -- each has a constant orientation, and there
is a (constant) rotation between them. It is acceleration that rotates
an object in spacetime, not inertial motion.

> Length is an invariant in SR.

This is too ambiguous to have any meaning. The proper length of an
object is an invariant, but measurements of its length by different
observers need not be equal.

> Time "dilation" is,
> essentially an "optical illusion".

Not at all -- you REALLY need to learn what the words you use actually mean.

For instance, "time dilation" permits Fermilab and CERN to build
high-energy pion beamlines a kilometer long -- no "illusion" could do that.

> Time
> dilation *cannot* be physically real because *both* observers see the
> *other* dilated,

You are confused. Yes, for two inertial observers moving differently
they each see the other's clock ticking slower than their own. There is
no contradiction or problem here, as they are making DIFFERENT MEASUREMENTS.

"Time dilation" and "length contraction" are geometrical projections,
and must therefore behave as such projections do. That includes being
reciprocal under appropriate circumstances (such as between inertial
frames).

> much like both observers viewing the other through a
> magnifying glass see the other larger.

Not at all. Rather, this is like you and your friend seeing each other
as smaller when you are further apart. This is GEOMETRY, not optics.

> Its nonsensical for both
> observers to be physically larger.

Yes, that would be nonsensical, but relativity does not predict that.
Both "Length contraction" and "time dilation" are about the way
measurements behave under certain geometrical projections. For them, no
object changes (proper) length, and no clock changes its (proper) tick rate.
When your friend walks away from you, you see them
getting progressively smaller. Do you really think that
they are physically smaller, or is this just an artifact
of the way you are observing them? -- Ditto for "length
contraction" and "time dilation".

I repeat: you REALLY need to learn something about the subject before
attempting to write about it.

Tom Roberts

On Saturday, 17 July 2021 at 22:30:29 UTC+2, tjrob137 wrote:
> On 7/15/21 1:29 PM, Kevin Aylward wrote:
> > Coordinate systems have no physical content whatsoever. Period. They
> > are simply labels on events. Events don't depend on coordinates.
> Yes to all that.
> > "inertial coordinates" is, technically, a meaningless statement.
> No. Not even close.
>
> Coordinates of an inertial frame are special, in that inertia is
> homogeneous and isotropic relative to them, and the laws of physics take
> their simplest form when projected onto such coordinates.

And we're all FORCED!!! To THE BEST WAY!!!!
An idiot has said, must be true.

On Saturday, July 17, 2021 at 4:30:29 PM UTC-4, tjrob137 wrote:
> On 7/15/21 1:29 PM, Kevin Aylward wrote:
> > Coordinate systems have no physical content whatsoever. Period. They
> > are simply labels on events. Events don’t depend on coorat dinates.
> Yes to all that.
> > "inertial coordinates" is, technically, a meaningless statement.
> No. Not even close.
>
> Coordinates of an inertial frame are special, in that inertia is
> homogeneous and isotropic relative to them, and the laws of physics take
> their simplest form when projected onto such coordinates.
The only frame that satisfies such conditions is a frame that is constructed within the stationary aether and Einstein call such frame an inertial frame.

> > Coordinates systems are abstractions, they have no physical
> > properties at all.
> Hmmmm. The numbers themselves have no physical properties, but
> coordinates on an inertial frame have the properties I just described.
> > For example, one can have a rotating coordinate system describing an
> > inertial frame,
> That is an oxymoron -- you need to learn what these words actually mean.
>
> Hint: an inertial frame is a FRAME, with mutually
> orthogonal coordinate axes. No rotating coordinates have
> mutually orthogonal axes. Note these are all coordinates
> on spacetime, not just space.
> > Coordinate systems and physical reference frames are not the same.
> You attempt to make a distinction without a difference. In normal usage
> among physicists, inertial coordinates and the frame they implement are
> synonymous.
>
> Yes, technically there are an infinite number of
> coordinate systems on a given inertial frame, differing
> by spatial rotations. We ignore this technicality as it
> is invariably irrelevant to the discussion.
> > *Physical* "length contraction" is a feature of LET (Lorentz Ether
> > Theory) not SR.
> Yes.
> > The "length" of an object in SR rotates in
> > "space-time".
> Hmmmm. Your words are too ambiguous and imprecise.
>
> When different observers measure the length of a given object, that
> object's length does not change and does not "rotate in spacetime";
> rather it is the different observers' instruments that are oriented
> differently in spacetime.
>
> IOW: objects at rest in different inertial frames are oriented
> differently in spacetime -- each has a constant orientation, and there
> is a (constant) rotation between them. It is acceleration that rotates
> an object in spacetime, not inertial motion.
> > Length is an invariant in SR.
> This is too ambiguous to have any meaning. The proper length of an
> object is an invariant, but measurements of its length by different
> observers need not be equal.
> > Time "dilation" is,
> > essentially an "optical illusion".
> Not at all -- you REALLY need to learn what the words you use actually mean.
>
> For instance, "time dilation" permits Fermilab and CERN to build
> high-energy pion beamlines a kilometer long -- no "illusion" could do that.
> > Time
> > dilation *cannot* be physically real because *both* observers see the
> > *other* dilated,
>
> You are confused. Yes, for two inertial observers moving differently
> they each see the other's clock ticking slower than their own. There is
> no contradiction or problem here, as they are making DIFFERENT MEASUREMENTS.
>
> "Time dilation" and "length contraction" are geometrical projections,
> and must therefore behave as such projections do. That includes being
> reciprocal under appropriate circumstances (such as between inertial
> frames).
> > much like both observers viewing the other through a
> > magnifying glass see the other larger.
> Not at all. Rather, this is like you and your friend seeing each other
> as smaller when you are further apart. This is GEOMETRY, not optics.
> > Its nonsensical for both
> > observers to be physically larger.
> Yes, that would be nonsensical, but relativity does not predict that.
> Both "Length contraction" and "time dilation" are about the way
> measurements behave under certain geometrical projections. For them, no
> object changes (proper) length, and no clock changes its (proper) tick rate.
> When your friend walks away from you, you see them
> getting progressively smaller. Do you really think that
> they are physically smaller, or is this just an artifact
> of the way you are observing them? -- Ditto for "length
> contraction" and "time dilation".
>
> I repeat: you REALLY need to learn something about the subject before
> attempting to write about it.
>
> Tom Roberts

On July 9, Kevin Aylward wrote:
> Sure, when one measure clocks they are differences associated with motion.
> That is *not* in dispute. We know, clocks read different, it *why*
> is what is in debate.
>
> SR states that these differences are *not* because clocks *physically* tick
> less, but that they cover more "space-time", that is travel into the future
> say at a rate of 100sec/sec
>
> LET type approaches state that the clock really do tick less as the POR
> states that clocks *must *tick the independent of inertial motion.
> LET approaches state that clocks *do* actually slow down and achieves this
> by rejecting the POR. The POR is taken to be a measurement artefact.

Your notion that "clocks slow down" is nebulous.
I'm curious regarding your concept/definition of time and clock.

Al has a Timex, with which he times a leaky faucet.
Bob has identical clock and faucet, in his new Tesla Model S,
on the Utah salt flats.
Do they record different ticks/drip rate?

i.e. Your claim that clock rate and POR is tautological, hence
unfalsifiable, is false. The point is, the 'true clock rate' is a
vacuous concept, in isolation. Clocks have only one function:
to record process evolution. Processes evolve, at rates which
may or may not depend on frame velocity; an empirical question.

You're confused because you believe that time is something
separate from physical processes, therefore it can slow.
Modern physics denies this.

A million years of evolution is hard to overcome -

Sean Carroll suggested we banish 'time' from our vocabulary,
replacing it with 'clock states' and 'process states', observing their
correspondence. This provides a precise operational definition of
time, avoiding the semantic thorns.

--
Rich