Python <python@python.invalid> wrote:
> Richard Hertz wrote:
> ...
>> BODKIN, THE AMATEUR TRYING TO GRASP GENERAL RELATIVITY (2018)
>>
>> bod...@gmail.com
>> Mar 14, 2018, 3:07:37 PM
>>
>>> With the (-,+,+,+) signature, ds² is negative.
>>
>> It is negative for timelike intervals, not for spacelike intervals. Obviously.
>>
>>> To normal people, one would ask WTF when the distance
>>
>> What’s the connection? ds^2 is not a distance. There is no distance that’s
>> negative when ds^2 is negative. Again, you have a bad habit of looking at
>> math and then just fabricating what you think the terms mean.
>>
>> *******************************************
>>
>> Bodkin, repent!
>
> Richard, you'd better study what is a positive-definite and a
> non positive-definite bilinear form instead of making (again)
> a fool of yourself.
>
> https://en.wikipedia.org/wiki/Definite_quadratic_form
>

FWIW, I don’t think he’s actually disputing the difference in sign for
timelike and spacelike intervals. (If he did, then he’d just be revealing
yet another place, as you say, where he’s scoffing about things from an
apparent position of ignorance.) I think he’s complaining about the
*attitude* or *tone* of my responses, and his post was some attempt to
recount how that tone has changed over the years — as though that’s
material to anything. So I think his complaint is about the sentence,
“Again, you have a bad habit of looking at the math and then just
fabricating what you think the terms mean.” This is similar to his recent
foolishness where he cited a place in one of Einstein’s paper where the
term (c+v) appears and crowing that writing such a thing down is
incompatible with the maximum speed being c. And in that case also, I think
it’s appropriate to repeat: “Again, you have a bad habit of looking at the
math and then just fabricating what you think the terms mean.” At this
point, he bristles and tells me to mind my manners and respect my elders.
To which I’ve responded that once he demonstrates that he knows what he’s
talking about with regard to physics, then he’ll earn some respect. He
clearly offers no respect to physicists (unless it’s the physics he used in
his career as a EE) in a group devoted to fans of physics, so I have no
idea why he thinks this is due him.

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

On Wednesday, October 6, 2021 at 1:09:28 PM UTC-3, bodk...@gmail.com wrote:
> Python <pyt...@python.invalid> wrote:
> > Richard Hertz wrote:
> > ...
> >> BODKIN, THE AMATEUR TRYING TO GRASP GENERAL RELATIVITY (2018)
> >>
> >> bod...@gmail.com
> >> Mar 14, 2018, 3:07:37 PM
> >>
> >>> With the (-,+,+,+) signature, ds² is negative.
> >>
> >> It is negative for timelike intervals, not for spacelike intervals. Obviously.
> >>
> >>> To normal people, one would ask WTF when the distance
> >>
> >> What’s the connection? ds^2 is not a distance. There is no distance that’s
> >> negative when ds^2 is negative. Again, you have a bad habit of looking at
> >> math and then just fabricating what you think the terms mean.
> >>
> >> *******************************************
> >>
> >> Bodkin, repent!
> >
> > Richard, you'd better study what is a positive-definite and a
> > non positive-definite bilinear form instead of making (again)
> > a fool of yourself.
> >
> > https://en.wikipedia.org/wiki/Definite_quadratic_form
> >
> FWIW, I don’t think he’s actually disputing the difference in sign for
> timelike and spacelike intervals. (If he did, then he’d just be revealing
> yet another place, as you say, where he’s scoffing about things from an
> apparent position of ignorance.) I think he’s complaining about the
> *attitude* or *tone* of my responses, and his post was some attempt to
> recount how that tone has changed over the years — as though that’s
> material to anything. So I think his complaint is about the sentence,
> “Again, you have a bad habit of looking at the math and then just
> fabricating what you think the terms mean.” This is similar to his recent
> foolishness where he cited a place in one of Einstein’s paper where the
> term (c+v) appears and crowing that writing such a thing down is
> incompatible with the maximum speed being c. And in that case also, I think
> it’s appropriate to repeat: “Again, you have a bad habit of looking at the
> math and then just fabricating what you think the terms mean.” At this
> point, he bristles and tells me to mind my manners and respect my elders.
> To which I’ve responded that once he demonstrates that he knows what he’s
> talking about with regard to physics, then he’ll earn some respect. He
> clearly offers no respect to physicists (unless it’s the physics he used in
> his career as a EE) in a group devoted to fans of physics, so I have no
> idea why he thinks this is due him.
> --
> Odd Bodkin -- maker of fine toys, tools, tables

Nice try, Bodkin.

Yet, I've an edge over you about THEORETICAL and PRACTICAL physics and engineering.

While you NEVER used your textbook knowledge, I used my hands-on developed knowledge
in REAL lab experiments, and I did while you was a fantasy on your parents biology (even they
met, probably). Count the difference in years:

Me: Active working on lab since 1970 up to 2005, and being accountable for mistakes to my bosses.
You: Passive reader of science books since 2000 up to 2021 (100+ books, etc..)

My tools: Everyone that several branches of applied physics, mathematics and several branches of engineering.
Your tools: Your mind.

My written production: More than 30,000 pages of technical and scientific work, plus 300,000 lines of SW.
Your written production: About 8 x 12 x 100 posts on this site, or 9,600+ posts.

My attitude toward scientific work with others: Interact, discuss, present results, discuss outcomes of experiments, etc.
on a basis of mutual respect and collaboration.

Your attitude toward posts that hit a nerve on your "pretorian guard of relativity" reflexes: To shill, troll, produce fallacious
posts, use "ad-hominem attacks" and "straw man" rhetorical tools against anyone who dares to touch einstenian topics.
Some of your usual "forum slang" comments, along the years:

- You don't understand how science works.
- You don't known anything about modern physics.
- You don't understand the scientific method.
- You don't know physics. You need to learn.
- You can't deal even with elementary math.
- You don't know what a quantum field is.
- You are an idiot (ignorant, amateur, stupid and other variations).

Yet, you became a Supreme Thinker and an Absolute Judge of Meanings in Posts, without any MERIT.

I perceive you as some kind of Kardashian type of person. And you love it.

Richard Hertz <hertz778@gmail.com> wrote:
> On Wednesday, October 6, 2021 at 1:09:28 PM UTC-3, bodk...@gmail.com wrote:
>> Python <pyt...@python.invalid> wrote:
>>> Richard Hertz wrote:
>>> ...
>>>> BODKIN, THE AMATEUR TRYING TO GRASP GENERAL RELATIVITY (2018)
>>>>
>>>> bod...@gmail.com
>>>> Mar 14, 2018, 3:07:37 PM
>>>>
>>>>> With the (-,+,+,+) signature, ds² is negative.
>>>>
>>>> It is negative for timelike intervals, not for spacelike intervals. Obviously.
>>>>
>>>>> To normal people, one would ask WTF when the distance
>>>>
>>>> What’s the connection? ds^2 is not a distance. There is no distance that’s
>>>> negative when ds^2 is negative. Again, you have a bad habit of looking at
>>>> math and then just fabricating what you think the terms mean.
>>>>
>>>> *******************************************
>>>>
>>>> Bodkin, repent!
>>>
>>> Richard, you'd better study what is a positive-definite and a
>>> non positive-definite bilinear form instead of making (again)
>>> a fool of yourself.
>>>
>>> https://en.wikipedia.org/wiki/Definite_quadratic_form
>>>
>> FWIW, I don’t think he’s actually disputing the difference in sign for
>> timelike and spacelike intervals. (If he did, then he’d just be revealing
>> yet another place, as you say, where he’s scoffing about things from an
>> apparent position of ignorance.) I think he’s complaining about the
>> *attitude* or *tone* of my responses, and his post was some attempt to
>> recount how that tone has changed over the years — as though that’s
>> material to anything. So I think his complaint is about the sentence,
>> “Again, you have a bad habit of looking at the math and then just
>> fabricating what you think the terms mean.” This is similar to his recent
>> foolishness where he cited a place in one of Einstein’s paper where the
>> term (c+v) appears and crowing that writing such a thing down is
>> incompatible with the maximum speed being c. And in that case also, I think
>> it’s appropriate to repeat: “Again, you have a bad habit of looking at the
>> math and then just fabricating what you think the terms mean.” At this
>> point, he bristles and tells me to mind my manners and respect my elders.
>> To which I’ve responded that once he demonstrates that he knows what he’s
>> talking about with regard to physics, then he’ll earn some respect. He
>> clearly offers no respect to physicists (unless it’s the physics he used in
>> his career as a EE) in a group devoted to fans of physics, so I have no
>> idea why he thinks this is due him.
>> --
>> Odd Bodkin -- maker of fine toys, tools, tables
>
> Nice try, Bodkin.
>
> Yet, I've an edge over you about THEORETICAL and PRACTICAL physics and engineering.
>
> While you NEVER used your textbook knowledge, I used my hands-on developed knowledge
> in REAL lab experiments, and I did while you was a fantasy on your
> parents biology (even they
> met, probably). Count the difference in years:
>
> Me: Active working on lab since 1970 up to 2005, and being accountable
> for mistakes to my bosses.
> You: Passive reader of science books since 2000 up to 2021 (100+ books, etc.)
>
> My tools: Everyone that several branches of applied physics, mathematics
> and several branches of engineering.
> Your tools: Your mind.
>
> My written production: More than 30,000 pages of technical and scientific
> work, plus 300,000 lines of SW.
> Your written production: About 8 x 12 x 100 posts on this site, or 9,600+ posts.
>
> My attitude toward scientific work with others: Interact, discuss,
> present results, discuss outcomes of experiments, etc.
> on a basis of mutual respect and collaboration.
>
> Your attitude toward posts that hit a nerve on your "pretorian guard of
> relativity" reflexes: To shill, troll, produce fallacious
> posts, use "ad-hominem attacks" and "straw man" rhetorical tools against
> anyone who dares to touch einstenian topics.
> Some of your usual "forum slang" comments, along the years:
>
> - You don't understand how science works.
> - You don't known anything about modern physics.
> - You don't understand the scientific method.
> - You don't know physics. You need to learn.
> - You can't deal even with elementary math.
> - You don't know what a quantum field is.
> - You are an idiot (ignorant, amateur, stupid and other variations).

I have no doubt you have quite a bit of experience about engineering, and
the application of a lot of classical physics in practical devices.

It is still true that, from how you have presented yourself, you are also
- Lacking meaningful working knowledge of quantum mechanics or relativity
- Lacking a good understanding of the value and role of non-applied,
fundamental physics
- Unfamiliar with how scientists check the validity of their ideas, not
having to conduct yourself in that kind of research.
- Shockingly unaware of your limitations, and as a consequence carelessly
pontificating about things you know nothing about.

I’ll repeat something that has been said to many a retired engineer on this
group since I’ve been on in the last 8 years or so: Decades of experience
as an engineer might qualify you to talk about engineering with some depth
and expertise, but it does not qualify you to talk about physics with depth
and expertise. This is an admonition that quite often draws a snort from
the engineer, but it is true just the same. What would qualify you to talk
about physics with depth and expertise is dedicated study of physics as
physics, not physics in support of an engineering career. Likewise, medical
doctors have to learn a modicum of organic chemistry as part of their
training, and they use organic chemistry from time to time in their work,
but they are NOT qualified to discuss organic chemistry as a peer with
professional chemists, let alone criticizing their work.

So do an ego check yourself. You are attempting to engage in a pissing
contest, but you’re well off the mark.

>
>
> Yet, you became a Supreme Thinker and an Absolute Judge of Meanings in
> Posts, without any MERIT.
>
> I perceive you as some kind of Kardashian type of person. And you love it.
>

Speaking of judging meaning in posts, that last comment just blew the fuse
in my irony meter, and the needle is still pegged.

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

Den 05.10.2021 22:44, skrev Richard Hertz:
> On Tuesday, October 5, 2021 at 4:09:28 PM UTC-3, Paul B. Andersen wrote:
>
> <snip>
>
>> The noble art of missing the point. :-D
>>
>> § 2 in Einstein's paper is
>> a simple demonstration of the FACT that 'relativity of simultaneity'
>> is an inevitable consequence of the invariance of the speed of light.
>>
>> If two clocks A and B are synchronous in one frame of reference
>> where the speed of light is c, then they can't be synchronous in
>> a frame where the clocks are moving _if the speed of light is c
>> also in this frame_.
>>
>> This fact should be obvious for any moderately intelligent person.
>>
>> Naive cranks often seem to believe that § 2. is meant to PROVE that
>> the speed of light is invariant, so it must be wrong, because cranks
>> KNOW that the speed of light NOT is invariant.
>>
>> Whether or not the speed of light is invariant can only be tested
>> by real experiments in the real world.
>
> <snip>
>
> Paul:
>
> 1) I have no problem accepting that the speed of light in vacuum is constant and isotropic.
> But I only believe that this is true in our cosmic neighborhood, because we don't have the means
> to prove it right or wrong away from our Solar System.
>
> 2) I also believe that this value only can be obtained by averaging a round trip in short distances (like
> in a lab. This is because any experiment involving high distances prevent the one-way measurement
> due to the simple fact that what is being measured is also involved in the way that communications
> should take place to bring results to one end or the other. That is, synchronization using EM waves
> to convey information corrupts the outcome of the experiment because "c" is the target to be measured
> and also "c" is the velocity at which the maximum speed results can be communicated.

Here is some of the experimental evidence that prove you wrong.
https://paulba.no/paper/Michelson_1913.pdf
https://paulba.no/paper/Kennedy_Thorndike.pdf
https://paulba.no/paper/Babcock_Bergman.pdf
https://paulba.no/paper/Alvager_et_al.pdf
https://paulba.no/paper/Brecher.pdf

>
> That is: the delay x/c involved in the information transfer appears twice: as a target and as a vehicle to
> convey information. The larger "x" is, the larger the delay involved and the difficulties to synchronize
> emitter and receptor, so the result is (IMO) not reliable.
>
> 3) I don't know if the speed of light is affected by gravity.

But we now know that the speed of light isn't affected by gravity,
but the velocity of light is.

If the speed of light had been affected by gravity,
the GPS wouldn't work.

> Einstein seemed to have a problem with this
> concept, so in 1911 published the first formula for c being affected by gravitational potentials.
>
> It helped him to introduce c retardation under the gravity of the Sun, to prove (in a fallacious way) the
> deflection of light due to gravity in 1911 (same result as von Soldner, 100 years before) and to double
> that value in 1915, alleging additional effects due to alleged curvature of space due to Sun's gravitational
> field.

Everybody, Einstein included, has since 1915 known that Einstein's
1911 paper is wrong so why are you so obsessed with it?

>
> Since the, light deflection due to Sun's gravity stuck with a simple formula:
>
> Deflection angle = 1.75"/(R/Rs) , where Rs is the Sun's radius... and R is the impact parameter.

Quite. And you know that this formula came with GR.
But this formula is only valid for small angels between Sun-star,
and now the deflection of EM-radiation is measured for angles Sun-star
up to 90 degrees.

GR gets it right for all angles.

https://paulba.no/paper/PPN_gamma_Hipparcos.pdf
https://paulba.no/paper/PPN_gamma_Cassini.pdf
https://paulba.no/paper/Shapiro_2004.pdf
https://paulba.no/paper/GravDeflection.pdf
https://paulba.no/paper/Fomalont.pdf
https://paulba.no/paper/PPN_gamma_Cassini_2.pdf

>
> But, as Eddington and colleagues, whom wrote a detailed report of the expeditions (42 pages)
> mentioned that such effect could be explained by a refraction index of 1.00004, which they stated
> as being impossible to happen, due to impositions on composition of solar atmosphere.

Many others have tried to save the Newtonian prediction by refraction
in the solar solar atmosphere. It doesn't work.

>
> 4) I resent the use of "crank" or "crackpot" for being RACIST. Applied to "a person who holds an unshakable
> belief that most of their contemporaries consider to be false" it also can be applied to religion, politics,
> gender perception, sexuality, belief on his race, art, philosophy, mathematics, humor, diets, etc.
>
> It's widely discriminatory and a defense mechanism for persons who can't accept dissent, with the childish
> expectations that their belief will be reassured by neglecting minorities rights.
>
> I don't like the use of these words, because they hold a classism embedded, as with royalties thinking
> that those beneath them are worthless and undeserving.
>
> See? Not a crank, just a person that don't like to follow the mainstream because of its forced
> impositions to free thoughts, even when the current (and poor) mathematics supporting it points
> in one direction. Mathematics is not a language, just a mechanism. And when I say poor it's because
> it only has been around for 300 years and still can't describe nature (algebra, geometry, basic and
> advanced calculus, matrix, quaternions, vector algebra, tensor algebra, binary algebra, etc.).
>
> What is neglected today can be accepted tomorrow, as knowledge evolves (always does).
>

I haven't called you a crank.

But the hallmark of a crank is that he trust his own belief
more than the experimental evidence that prove him wrong.

It's up to you if you will belong to said group of people.

I note however that you invariably snip all references
to experimental evidence with no comment.

Like you did in your post quoted above:

You snipped _everything_ I wrote!

Paul B. Andersen wrote:
> § 2 in Einstein's paper is
> a simple demonstration of the FACT that 'relativity of simultaneity'
> is an inevitable consequence of the invariance of the speed of light.
>
> If two clocks A and B are synchronous in one frame of reference
> where the speed of light is c, then they can't be synchronous in
> a frame where the clocks are moving _if the speed of light is c
> also in this frame_.
>
> This fact should be obvious for any moderately intelligent person.
>
> Naive cranks often seem to believe that § 2. is meant to PROVE that
> the speed of light is invariant, so it must be wrong, because cranks
> KNOW that the speed of light NOT is invariant.

(It's up to you if you will belong to said group of people.)

>
> Whether or not the speed of light is invariant can only be tested
> by real experiments in the real world.
>
> Here is some of the experimental evidence:
> https://paulba.no/paper/Michelson_1913.pdf
> https://paulba.no/paper/Kennedy_Thorndike.pdf
> https://paulba.no/paper/Babcock_Bergman.pdf
> https://paulba.no/paper/Alvager_et_al.pdf
> https://paulba.no/paper/Brecher.pdf
>
> You will of course ignore this.
> Experimental evidence has no place in your world, has it?

BTW, thanks for confirming my words.

--
Paul

https://paulba.no/

Den 06.10.2021 21:58, skrev Paul B. Andersen:
>
>
>
> I haven't called you a crank.
>
> But the hallmark of a crank is that he trust his own belief
> more than the experimental evidence that prove him wrong.
>
> It's up to you if you will belong to said group of people.
>
> I note however that you invariably snip all references
> to experimental evidence with no comment.
>
> Like you did in your post quoted above:
>
> You snipped _everything_ I wrote!

You didn't snip everything I wrote,
I meant to say that you snipped every
reference to experimental evidence I wrote:

> Paul B. Andersen wrote:
>>
>> Whether or not the speed of light is invariant can only be tested
>> by real experiments in the real world.
>>
>> Here is some of the experimental evidence:
>> https://paulba.no/paper/Michelson_1913.pdf
>> https://paulba.no/paper/Kennedy_Thorndike.pdf
>> https://paulba.no/paper/Babcock_Bergman.pdf
>> https://paulba.no/paper/Alvager_et_al.pdf
>> https://paulba.no/paper/Brecher.pdf
>>
>> You will of course ignore this.
>> Experimental evidence has no place in your world, has it?
>
> BTW, thanks for confirming my words.
>

--
Paul

https://paulba.no/

On Wednesday, 6 October 2021 at 21:58:38 UTC+2, Paul B. Andersen wrote:
> Den 05.10.2021 22:44, skrev Richard Hertz:
> > On Tuesday, October 5, 2021 at 4:09:28 PM UTC-3, Paul B. Andersen wrote:
> >
> > <snip>
> >
> >> The noble art of missing the point. :-D
> >>
> >> § 2 in Einstein's paper is
> >> a simple demonstration of the FACT that 'relativity of simultaneity'
> >> is an inevitable consequence of the invariance of the speed of light.
> >>
> >> If two clocks A and B are synchronous in one frame of reference
> >> where the speed of light is c, then they can't be synchronous in
> >> a frame where the clocks are moving _if the speed of light is c
> >> also in this frame_.
> >>
> >> This fact should be obvious for any moderately intelligent person.
> >>
> >> Naive cranks often seem to believe that § 2. is meant to PROVE that
> >> the speed of light is invariant, so it must be wrong, because cranks
> >> KNOW that the speed of light NOT is invariant.
> >>
> >> Whether or not the speed of light is invariant can only be tested
> >> by real experiments in the real world.
> >
> > <snip>
> >
> > Paul:
> >
> > 1) I have no problem accepting that the speed of light in vacuum is constant and isotropic.
> > But I only believe that this is true in our cosmic neighborhood, because we don't have the means
> > to prove it right or wrong away from our Solar System.
> >
> > 2) I also believe that this value only can be obtained by averaging a round trip in short distances (like
> > in a lab. This is because any experiment involving high distances prevent the one-way measurement
> > due to the simple fact that what is being measured is also involved in the way that communications
> > should take place to bring results to one end or the other. That is, synchronization using EM waves
> > to convey information corrupts the outcome of the experiment because "c" is the target to be measured
> > and also "c" is the velocity at which the maximum speed results can be communicated.
> Here is some of the experimental evidence that prove you wrong.
> https://paulba.no/paper/Michelson_1913.pdf
> https://paulba.no/paper/Kennedy_Thorndike.pdf
> https://paulba.no/paper/Babcock_Bergman.pdf
> https://paulba.no/paper/Alvager_et_al.pdf
> https://paulba.no/paper/Brecher.pdf
>
> >
> > That is: the delay x/c involved in the information transfer appears twice: as a target and as a vehicle to
> > convey information. The larger "x" is, the larger the delay involved and the difficulties to synchronize
> > emitter and receptor, so the result is (IMO) not reliable.
> >
> > 3) I don't know if the speed of light is affected by gravity.
> But we now know that the speed of light isn't affected by gravity,

Maybe you know, but your Shit states oppositely. Doesn't matter,
of course, since GPS clocks keep measuring t'=t, just like all
serious clocks always did.

> > Deflection angle = 1.75"/(R/Rs) , where Rs is the Sun's radius... and R is the impact parameter.
>
> Quite. And you know that this formula came with GR.

According to your Shit light rays in vacuum are actually following
straight lines.

Paul B. Andersen wrote:

> § 2 in Einstein's paper is
> a simple demonstration of the FACT that 'relativity of simultaneity'
> is an inevitable consequence of the invariance of the speed of light.
>
> If two clocks A and B are synchronous in one frame of reference
> where the speed of light is c, then they can't be synchronous in
> a frame where the clocks are moving _if the speed of light is c
> also in this frame_.
>
> This fact should be obvious for any moderately intelligent person.

And if not, recently I found a very nice demonstration that should convince
such a person of that fact:

<https://www.youtube.com/watch?v=XBwGuHjwHPk>

PointedEars
--
A neutron walks into a bar and inquires how much a drink costs.
The bartender replies, "For you? No charge."

(from: WolframAlpha)

On Wednesday, October 6, 2021 at 5:08:42 PM UTC-3, Paul B. Andersen wrote:

<snip>

> > I haven't called you a crank.
> >
> > But the hallmark of a crank is that he trust his own belief
> > more than the experimental evidence that prove him wrong.
> >
> > It's up to you if you will belong to said group of people.
> >
> > I note however that you invariably snip all references to experimental evidence with no comment.
> >
> > Like you did in your post quoted above:
> >
> > You snipped _everything_ I wrote!

> You didn't snip everything I wrote, I meant to say that you snipped every reference to experimental evidence I wrote:

> > Paul B. Andersen wrote:
> >>
> >> Whether or not the speed of light is invariant can only be tested by real experiments in the real world.
> >>
> >> Here is some of the experimental evidence:
> >> https://paulba.no/paper/Michelson_1913.pdf
> >> https://paulba.no/paper/Kennedy_Thorndike.pdf
> >> https://paulba.no/paper/Babcock_Bergman.pdf
> >> https://paulba.no/paper/Alvager_et_al.pdf
> >> https://paulba.no/paper/Brecher.pdf
> >>
> >> You will of course ignore this. Experimental evidence has no place in your world, has it? BTW, thanks for confirming my words.

Paul, I don't mutilate other's people posts on purpose. I left it for Dono's kind of lifeforms.

I didn't understand that you wanted me to read and comment about your links.

I'll read them later, and let you know. It seems to be about relativistic derivation of Sagnac's formula.

On Saturday, October 9, 2021 at 3:38:12 PM UTC-3, Thomas 'PointedEars' Lahn wrote:

Thomas, I didn't apologize to you in due form for my post about errors on your derivations.

I copy my explanation, given in another thread. I apologize for not seeing the small dots.

I just didn't know that diacritics would render as v̇ or u̇, instead of ṗ, ṅ, ċ.

You can fact-check by yourself, if you make copy&paste from here: https://en.wikipedia.org/wiki/Dot_(diacritic)

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
On Saturday, October 9, 2021 at 5:38:06 PM UTC-3, Michael Moroney wrote:
<snip>
> So you blame Odd and Lahn for having either poor eyeglasses, a dirty screen or a broken web browser?

No, I don't. Now, after SEEING the dust spot on the upper left of γ, I understand that Thomas meant:

̇γ = dγ/dt = dγ/dv . dv/dt = v/c² γ³ dv/dt = v/c² γ³ a

I didn't see the tiny dot spot on the upper right or left of v and γ.
Superscript dots fail when using copy&paste from https://en.wikipedia.org/wiki/Dot_(diacritic).
Like in v̇ or u̇, but not in ṗ, ṅ, ċ.
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------

On Saturday, 9 October 2021 at 20:38:12 UTC+2, Thomas 'PointedEars' Lahn wrote:
> Paul B. Andersen wrote:
>
> > § 2 in Einstein's paper is
> > a simple demonstration of the FACT that 'relativity of simultaneity'
> > is an inevitable consequence of the invariance of the speed of light.
> >
> > If two clocks A and B are synchronous in one frame of reference
> > where the speed of light is c, then they can't be synchronous in
> > a frame where the clocks are moving _if the speed of light is c
> > also in this frame_.
> >
> > This fact should be obvious for any moderately intelligent person.
> And if not, recently I found a very nice demonstration that should convince
> such a person of that fact:
>
> <https://www.youtube.com/watch?v=XBwGuHjwHPk>

In the meantime in the real world, however, GPS clocks
keep measuring t'=t, just like all serious clocks always
did.

On October 6, Paul B. Andersen wrote:
> But we now know that the speed of light isn't affected by gravity,
> but the velocity of light is.
> If the speed of light had been affected by gravity,
> the GPS wouldn't work.

Not so.

If light speed were modulated by gravity, the receiver would
misjudge the distance to the satellite. But if we examine the
algorithms to determine the receiver's location, the set of
equations, we see that doesn't matter, because such errors
would cancel, assuming all radio signals are affected equally,
as they fall through the potential well. The receiver would still
calculate the correct {r, θ, φ} co-ordinates, in the ECI frame.

--
Rich

Richard Hertz <hertz778@gmail.com> wrote:
> On Saturday, October 9, 2021 at 3:38:12 PM UTC-3, Thomas 'PointedEars' Lahn wrote:
>
> Thomas, I didn't apologize to you in due form for my post about errors on your derivations.
>
> I copy my explanation, given in another thread. I apologize for not seeing the small dots.
>
> I just didn't know that diacritics would render as v̇ or u̇, instead of ṗ, ṅ, ċ.
>
> You can fact-check by yourself, if you make copy&paste from here:
> https://en.wikipedia.org/wiki/Dot_(diacritic)
>
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------
> On Saturday, October 9, 2021 at 5:38:06 PM UTC-3, Michael Moroney wrote:
> <snip>
>> So you blame Odd and Lahn for having either poor eyeglasses, a dirty
>> screen or a broken web browser?
>
> No, I don't. Now, after SEEING the dust spot on the upper left of γ, I
> understand that Thomas meant:
>
̇γ = dγ/dt = dγ/dv . dv/dt = v/c² γ³ dv/dt = v/c² γ³ a
>
> I didn't see the tiny dot spot on the upper right or left of v and γ.
> Superscript dots fail when using copy&paste from
> https://en.wikipedia.org/wiki/Dot_(diacritic).
> Like in v̇ or u̇, but not in ṗ, ṅ, ċ.
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>

This king of kerfuffle is why I don’t go to great pains to render math in
an unsuitable medium.

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

This king of kerfuffle is why I don’t go to great pains to render math in
an unsuitable medium. --
Odd Bodkin -- maker of fine toys, tools, tables

"The only aether which has survived is that which was invented by Huygens to explain the propagation of light. The evidence for the existence of the luminiferous aether has accumulated as additional phenomena of light and radiation have been discovered" (Maxwell, Part XCVII, p. 764).

"If we adopt either Fresnel's or Maccullagh's form of the undulatory theory, half of this energy is in the form of potential energy, due to the distortion of elementary portions of the medium, and half in the form of kinetic energy, due to the motion of the medium. We must therefore regard the aether as possessing elasticity similar to that of a solid body, and also as having a finite density." (Maxwell, Part XCVII, p. 767).

On 10/10/21 6:16 PM, RichD wrote:
> If light speed were modulated by gravity, the receiver would
> misjudge the distance to the satellite. But if we examine the
> algorithms to determine the receiver's location, the set of
> equations, we see that doesn't matter, because such errors
> would cancel, assuming all radio signals are affected equally,

No, the errors would not cancel, as each satellite must follow a valid
orbit around the earth, and that is not affected by lightspeed.

Tom Roberts

Richard Hertz wrote:

> On Saturday, October 9, 2021 at 3:38:12 PM UTC-3, Thomas 'PointedEars'
> Lahn wrote:
>
> Thomas, I didn't apologize to you in due form for my post about errors on
> your derivations.
>
> I copy my explanation, given in another thread.

You should at least have provided the Message-ID, news URI, or Google Groups
URI:

<f987aa9a-6e85-411f-ac0b-b332600cb855n@googlegroups.com>

<news:f987aa9a-6e85-411f-ac0b-b332600cb855n@googlegroups.com>

<https://groups.google.com/forum/?hl=en#!search/messageidAf987aa9a-6e85-411f-ac0b-b332600cb855n@googlegroups.com>

> I apologize for not seeing the small dots.

Apology noted and accepted.

But *please* keep (to) the thread. You are here replying *anywhere* just
because you are replying to a posting of mine. That is not appropriate in
Usenet. If you must use the horribly broken Web interface of Google Groups
instead of a proper newsreader, at least use the “Reply” button *next to the
posting that you want to reply to*.

If you do that, then there is also usually no need to refer to a precursor
by any of the IDs above.

> I just didn't know that diacritics would render as v̇ or u̇, instead of
> ṗ, ṅ, ċ.

I do not know what you mean, as I do not see a difference there: I see the
Unicode equivalents of the LaTeX commands \dot{v}, \dot{u}, \dot{p},
\dot{n}, and \dot{c}.
> You can fact-check by yourself, if you make copy&paste from here:
> https://en.wikipedia.org/wiki/Dot_(diacritic)

I am aware that copying and pasting text from the Web is not always an exact
representation of the original text – there is much to be improved in Web
browsers there.

But why have you *copied* anything in the first place? I do not see a need.
>
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------
> On Saturday, October 9, 2021 at 5:38:06 PM UTC-3, Michael Moroney wrote:
> <snip>
>> So you blame Odd and Lahn for having either poor eyeglasses, a dirty
>> screen or a broken web browser?
>
> No, I don't. Now, after SEEING the dust spot on the upper left of γ, I
> understand that Thomas meant:
>
> ̇γ = dγ/dt = dγ/dv . dv/dt = v/c² γ³ dv/dt = v/c² γ³ a

Yes, correct.
> […]
>
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------

PointedEars
--
Q: What happens when electrons lose their energy?
A: They get Bohr'ed.

(from: WolframAlpha)

Paul B. Andersen wrote:

> But we now know that the speed of light isn't affected by gravity,
> but the velocity of light is.
>
> If the speed of light had been affected by gravity,
> the GPS wouldn't work.

That is utter nonsense; you should know better.

Neither is affected by gravity as gravity does not exist in that theory,
or IOW it is reduced to an observable effect due to the curvature of
spacetime.

The coordinate speed of light in vacuum is affected by the curvature of
spacetime as well (it is less than c₀); the local speed of light in vacuum
is not. This manifests itself e.g. in Shapiro delay.

And IIUC, the velocity of light is ill-defined in curved spacetime.

PointedEars
--
“Nature uses only the longest threads to weave her patterns
so that each small piece of her fabric reveals the organization
of the entire tapestry.”
—Richard Feynman, theoretical physicist, “Messenger Lecture” 1 (1964)

On Saturday, October 16, 2021 at 7:53:32 PM UTC-5, Thomas 'PointedEars' Lahn wrote:
> Paul B. Andersen wrote:
>
> > But we now know that the speed of light isn't affected by gravity,
> > but the velocity of light is.
> >
> > If the speed of light had been affected by gravity,
> > the GPS wouldn't work.
> That is utter nonsense; you should know better.
>
> Neither is affected by gravity as gravity does not exist in that theory,
> or IOW it is reduced to an observable effect due to the curvature of
> spacetime.

You are being overly pedantic. Terms such as "speed of light" and
"velocity of light" depend on the language/theory of description.
Paul was assuming that a typical non-crackpot reader should be
perfectly capable of determining from context whether he meant
coordinate speed or local speed of light; likewise, he assumed that
a typical non-crackpot reader should be perfectly aware in what
context he meant that the velocity of light is observed to vary.

As you noted, Paul DOES know better. He also knows that being
concise in his language is often better than being overly precise
and fastidious, especially when the true audience to which he
directs his remarks consists of his peers and the non-crackpot
10% of this newsgroup's membership.

If you wish to critique another's use of language, you should not
be obnoxious about it, unless that other is a crackpot. You yourself
are not innocent of occasional laxity of expression, both deliberate
(at times) and inadvertent (at other times).

On Sunday, 17 October 2021 at 03:43:34 UTC+2, prokaryotic.c...@gmail.com wrote:
> On Saturday, October 16, 2021 at 7:53:32 PM UTC-5, Thomas 'PointedEars' Lahn wrote:
> > Paul B. Andersen wrote:
> >
> > > But we now know that the speed of light isn't affected by gravity,
> > > but the velocity of light is.
> > >
> > > If the speed of light had been affected by gravity,
> > > the GPS wouldn't work.
> > That is utter nonsense; you should know better.
> >
> > Neither is affected by gravity as gravity does not exist in that theory,
> > or IOW it is reduced to an observable effect due to the curvature of
> > spacetime.
> You are being overly pedantic. Terms such as "speed of light" and
> "velocity of light" depend on the language/theory of description.
> Paul was assuming that a typical non-crackpot reader should be
> perfectly capable of determining from context whether he meant
> coordinate speed or local speed of light; likewise, he assumed that
> a typical non-crackpot reader should be perfectly aware in what
> context he meant that the velocity of light is observed to vary.
>
> As you noted, Paul DOES know better. He also knows that being

In the meantime in the real world, however, GPS clocks keep
measuring t'=t, just like serious clocks always did.

Restoring the context.
The significant part of the posting Thomas Lahn responded to:

|>> On Tuesday, October 5, 2021 at 4:09:28 PM UTC-3, Paul B. Andersen wrote:
|>>>
|>>> Whether or not the speed of light is invariant can only be tested
|>>> by real experiments in the real world.

The issue is the invariance of the speed of light.

|> Richard Hertz responded:
|>>
|>> <snip>
|>>
|>>
|>> 3) I don't know if the speed of light is affected by gravity.

Meaning that he doesn't know if light is falling
and accelerating in a gravitational field.
(With reference to Einstein's 1911 paper.)

Note that 'gravity' is used as a synonym for 'gravitation'.

> Paul B. Andersen responded:
>
>> But we now know that the speed of light isn't affected by gravity,
>> but the velocity of light is.
>>
>> If the speed of light had been affected by gravity,
>> the GPS wouldn't work.

Den 17.10.2021 02:53, skrev Thomas 'PointedEars' Lahn:
>
> That is utter nonsense; you should know better.

No, it's correct even if it appears imprecise and ambiguous
when quoted out of context. I used the word 'gravity' because
that was the word used by Richard Hertz.

The speed of light isn't affected by gravitation,
but the velocity of light is.

>
> Neither is affected by gravity as gravity does not exist in that theory,
> or IOW it is reduced to an observable effect due to the curvature of
> spacetime.

Gravitation does indeed exist in "the theory of gravitation" GR.
Gravitation isn't "reduced to an observable effect due to
the curvature of spacetime", it IS the curvature of spacetime.

So my statement is equivalent to:
"The speed of light isn't affected by the curvature of spacetime,
but the velocity of light is.

>
> The coordinate speed of light in vacuum is affected by the curvature of
> spacetime as well (it is less than c₀); the local speed of light in vacuum
> is not. This manifests itself e.g. in Shapiro delay.

Good grief! :-D

If I say: "the speed of light is invariant",
would you then say:
"No, the coordinate speed of light isn't invariant"
Or:
"No, the speed of light in a medium like glass isn't invariant."
Or:
"No, the speed of light measured in an accelerated frame isn't invariant."

No, you wouldn't say that, because even you will know that
the "speed of light" that is invariant is the local speed of
light in vacuum measured in a momentarily co-moving inertial frame.

>
> And IIUC, the velocity of light is ill-defined in curved spacetime.

If you are in free fall somewhere in space, then
the magnitude of the velocity (speed) of the light
from a star that hits you is c, because the magnitude of
the velocity (speed) isn't affected by the curvature of
the spacetime between you and the star.

But the direction of the velocity of the light
from a star that hits you is affected by the curvature
of the spacetime between you and the star.
So even if the star is stationary relative to you
(no aberration, no parallax), the star may not be
where you see it. (Gravitational deflection of light.)

IOW:
The speed of light isn't affected by gravitation,
but the velocity of light is.

--
Paul

https://paulba.no/

On Sunday, 17 October 2021 at 15:16:19 UTC+2, Paul B. Andersen wrote:
> So my statement is equivalent to:
> "The speed of light isn't affected by the curvature of spacetime,
> but the velocity of light is.

You don't know your Shit very well, then. What, of
course, was obvious before.

On Sunday, October 17, 2021 at 10:30:17 AM UTC-3, maluw...@gmail.com wrote:
----
> On Sunday, 17 October 2021 at 15:16:19 UTC+2, Paul B. Andersen wrote:
> > So my statement is equivalent to:
> > "The speed of light isn't affected by the curvature of spacetime, but the velocity of light is.

> You don't know your Shit very well, then. What, of course, was obvious before.

Sorry, but from high-school physics: "Speed is the scalar magnitude of the velocity, which is a vector, with
components on each of the three euclidean dimensions xyz".

You just can't talk about velocity of light. This expression is not specific. You may talk about:

1. The phase velocity is the velocity with which wavefronts propagate.
2. The group velocity determines the speed with which intensity maxima propagate (e.g. the peaks of pulses).

At any case, you have to define an specific xyz point in order to assign a vector to the rate of change of position at any
orthogonal direction. So, speed has no direction and velocity of light is an incomplete expression.

Not even with photons you can do that, unless you are willing to concede that a photon is represented by a point-like entity,
which clearly is not. And attempts to assign a velocity to a photon are incorrect, as it is not known what the spatial xyz
representation of a photon (volume, shape, duration).

So, velocity of light is an incorrect expression and should be used to express either concepts 1 or 2, clearly stated.

On 10/16/21 8:43 PM, Prokaryotic Capase Homolog wrote:
> On Saturday, October 16, 2021 at 7:53:32 PM UTC-5, Thomas
> 'PointedEars' Lahn wrote:
>> Paul B. Andersen wrote:
>>> But we now know that the speed of light isn't affected by
>>> gravity, but the velocity of light is.
>>>
>>> If the speed of light had been affected by gravity, the GPS
>>> wouldn't work.
>> That is utter nonsense; you should know better.
>>
>> Neither is affected by gravity as gravity does not exist in that
>> theory, or IOW it is reduced to an observable effect due to the
>> curvature of spacetime.
>
> You are being overly pedantic.

This is not overly pedantic, the original statements quoted above are
too imprecise, and are basically false.

Note that over NON-LOCAL paths the speed and velocity of light ARE
affected by the curvature of spacetime (aka gravity). Examples: a)
Shapiro delay, b) deflection of starlight by the sun, c) imaging of
distant astronomical objects by foreground galaxies (which includes both
delays and angular deflections).

Note that the LOCAL speed of light is not affected by the curvature of
spacetime (aka gravity). Because "local" means "a region small enough
that the curvature of spacetime has no measurable effect" (the size of
a local region depends on the measurement accuracy involved, and the
values of the curvature throughout the region).

So one cannot sensibly say "the speed of light is not affected by
gravity" -- that statement is wrong due to being insufficiently
precise: it does not distinguish between local and non-local paths; it
is correct for the former but incorrect for the latter.

>>> If the speed of light had been affected by gravity, the GPS
>>> wouldn't work.

This is also insufficiently precise, and basically wrong (the non-local
speed of light is affected by gravity, yet the GPS works).

Over the distances involved, and the accuracy used in the GPS, the
NON-LOCAL speed of light could easily be measured to be different from c
[#]. But the GPS does not use such measurements. Instead they construct
an ECI coordinate system in which COORDINATE clocks (and rulers) always
measure the COORDINATE speed of light (in vacuum) to be isotropically c.
All GPS clocks are modified so they display the COORDINATE time at their
current COORDINATE location. This ECI coordinate system is valid inside
the orbits of the GPS satellites, and out to about geosynchronous
altitude; it is certainly not valid on other planets.

[#] There are serious issues with such a measurement.
No matter, as such measurements are simply not used.

Tom Roberts

On Sunday, 17 October 2021 at 18:23:55 UTC+2, tjrob137 wrote:
> On 10/16/21 8:43 PM, Prokaryotic Capase Homolog wrote:
> > On Saturday, October 16, 2021 at 7:53:32 PM UTC-5, Thomas
> > 'PointedEars' Lahn wrote:
> >> Paul B. Andersen wrote:
> >>> But we now know that the speed of light isn't affected by
> >>> gravity, but the velocity of light is.
> >>>
> >>> If the speed of light had been affected by gravity, the GPS
> >>> wouldn't work.
> >> That is utter nonsense; you should know better.
> >>
> >> Neither is affected by gravity as gravity does not exist in that
> >> theory, or IOW it is reduced to an observable effect due to the
> >> curvature of spacetime.
> >
> > You are being overly pedantic.
> This is not overly pedantic, the original statements quoted above are
> too imprecise, and are basically false.
>
> Note that over NON-LOCAL paths the speed and velocity of light ARE
> affected by the curvature of spacetime (aka gravity). Examples: a)
> Shapiro delay, b) deflection of starlight by the sun, c) imaging of
> distant astronomical objects by foreground galaxies (which includes both
> delays and angular deflections).
>
> Note that the LOCAL speed of light is not affected by the curvature of
> spacetime (aka gravity). Because "local" means "a region small enough
> that the curvature of spacetime has no measurable effect" (the size of
> a local region depends on the measurement accuracy involved, and the
> values of the curvature throughout the region).
>
> So one cannot sensibly say "the speed of light is not affected by
> gravity" -- that statement is wrong due to being insufficiently
> precise: it does not distinguish between local and non-local paths; it
> is correct for the former but incorrect for the latter.
> >>> If the speed of light had been affected by gravity, the GPS
> >>> wouldn't work.
> This is also insufficiently precise, and basically wrong (the non-local
> speed of light is affected by gravity, yet the GPS works).
>
> Over the distances involved, and the accuracy used in the GPS, the
> NON-LOCAL speed of light could easily be measured to be different from c
> [#]. But the GPS does not use such measurements. Instead they construct
> an ECI coordinate system in which COORDINATE clocks (and rulers) always
> measure the COORDINATE speed of light

Ignoring poor idiot Tom screaming that they're FORCED
to THE BEST WAY.

> All GPS clocks are modified so they display the COORDINATE time at their
> current COORDINATE location.

Ignoring poor idiot Tom screaming that they're FORCED
to THE BEST WAY. Common sense was warning your
insane guru.

On 10/17/21 10:52 AM, Richard Hertz wrote:
> You just can't talk about velocity of light. This expression is not specific. You may talk about:
> 1. The phase velocity is the velocity with which wavefronts propagate.
> 2. The group velocity determines the speed with which intensity maxima propagate (e.g. the peaks of pulses).

You forgot the important one for relativity:
3. The front velocity is the speed with which the front of a wave
propagates when it is turning on; it is also the speed with
which modulation propagates.

[All three use the word "velocity", but in the German
sense that does not distinguish velocity from speed.]

Both phase and group velocity can be either larger or smaller than c
[@], depending on the properties of the medium in which the wave is
propagating; neither of them can transfer information, as they are
properties of an established, unmodulated wave. The front velocity [#]
is the one that applies to the transfer information, and it is strictly
<= c, with equality only in vacuum.

[@] It turns out that the product (phase velocity) *
(group velocity) is equal to c^2 for any ordinary
optical medium. Both equal c in vacuum.

[#] Occasionally called the modulation velocity.

In relativity, we only discuss the front velocity, and often omit the
adjective.

> [... further nonsense omitted.]

Tom Roberts

The 43"/century DISCREPANCY is from MEASUREMENTS of Mercury's orbit and
the difference between those MEASUREMENTS and predictions of its
precession from Newtonian mechanics. The discrepancy was known LONG
before Einstein. Einstein's GR was merely the first explanation of the
discrepancy, or at least the first explanation not shown to be incorrect
later.