As Volney and I averred in a thread, "frame-jumping" is often the cause
of errors in false claims about relativity. It's also been responsible
for misstatements about FTL phenomena even by physicists well-versed in relativistic problems. Take, for example, the simple situation:

C --> v _____ u' <---- D --> v
A _____________________ B

tA = tB = tC' = 0, xA = 0, xB = L.

Figure 1.

From relativity, we know that tD' = gamma(t - vL/c^2) = - vL/c^2 for the
above figure.

At the above times, D sends a signal back to C at velocity u' = -w'.
A and B observe the velocity of this signal as

u = (u' + v)/(1 + u'v/c^2) = (-w' + v)/(1 - w'v/c^2).

If w' = c, then u = (-c + v)/(1 - vc/c^2) = -c, and since v is always
less than c, this works when w < c, too. It even works for w < -c, let
w = -10c:

u = (10c + v)/(1 + 10v/c) = (10 + v/c)/(1 + v/c) > c

But it does not work for w/c >= c/v because the denominator causes u
to approach infinity at w = c^2/v. Getting an infinite result means
something is wrong: Either the physics is impossible or the physics is
beyond the equation's domain of applicability.

Nevertheless, many have pressed forward into the unknown and ignored
the "immense" warning sign. This leads to crazy results, such as a signal being received before it's sent. Others have thrown up their hands and succumbed to the belief that it's impossible. Some have even denied and denigrated the right of others to investigate the domain, which isn't a
very dynamic plan.

"The only way of discovering the limits of the possible is to venture a
little way past them into the impossible." -- Arthur C. Clarke

Anyway, back to Figure 1, which is situated in the frame where A and B are stationary. The time at C is tC' = 0 and the time at D is tD' = -vL/c^2. According to A and B, D can send the signal to C no faster than

w = (0 - L)/(0 + vL/c^2) = -c^2/v

The Throw-Up-Their-Hands crowd would point out that an observer cannot limit what someone in a different frame can do. Clearly, if B has some technology for sending FTL signals, as does D, then nothing prevents B from sending such
a signal, maybe even infinitely fast, to A, so D should not be constrained, either.

Are we frame-jumping by saying D can send an infinitely-fast signal, too?
The reason why A and B say that D cannot send a signal to C faster than c^2/v is because of the relativity of simultaneity RoS), which is a basic conse- quence of special relativity. Does conceding D's ability to send signals faster than c^2/v violate RoS? Of course, the TUTH crowd will just deny, denigrate or claim c is the limit, or do the limits of the possible extend further?

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Are we frame-jumping by saying D can send an infinitely-fast signal, too? The reason why A and B say that D cannot send a signal to C faster than c^2/v
is because of the relativity of simultaneity RoS), which is a basic conse- quence of special relativity. Does conceding D's ability to send signals faster than c^2/v violate RoS? Of course, the TUTH crowd will just deny, denigrate or claim c is the limit, or do the limits of the possible extend further?

Ross wrote:

Seems you need better mathematics of infinity.

No problem. QFT had problems, and they were resolved. Have you studied conformal mapping and complex variables?

https://mathworld.wolfram.com/ConformalMapping.html

There are ways to get around these problems in relativity, too. See
DOI: 10.13189/ujpa.2023.170101

Also you should probably be aware of "Einstein's bridge"

Do you mean the novel by John Cramer?

and "Einstein's second mass/energy equation that's not mc^2",
about singularities and central symmetries ("without infinities,
but, well, you know, with") and "flowing not jumping".

Are you referring to the stress-energy tensor?

Mathematics OWES physics, more and better physics of infinities,
particularly continuous domains about the conceit of particles,
really.

I didn't know particles were conceted. Sounds like a lot of buzz
words to me.

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Ross Finlayson wrote - Thu, 4 Jan 2024 11:45

On Thursday, January 4, 2024 at 8:36:20 AM UTC-8, gharnagel wrote:

Ross wrote:

Seems you need better mathematics of infinity.

No problem. QFT had problems, and they were resolved. Have you
studied conformal mapping and complex variables?

https://mathworld.wolfram.com/ConformalMapping.html

There are ways to get around these problems in relativity, too.
See DOI: 10.13189/ujpa.2023.170101

Also you should probably be aware of "Einstein's bridge"

Do you mean the novel by John Cramer?

Ross wrote:

Hi Gary, thanks for your reply.

"Einstein's bridge" is his notion of combining the linear and
rotational moment. It's a fundamental concept that students of
Einstein should know.

It is usually called an Einstein-Rosen bridge, or an Einstein-Rosen-
Podolski bridge, or simply a wormhole. The only place I know of
where it's called "Einstein's bridge" is in the novel by Cramer.
John Cramer is a particle physicist who wrote two scifi novels.

and "Einstein's second mass/energy equation that's not mc^2",
about singularities and central symmetries ("without infinities,
but, well, you know, with") and "flowing not jumping".

Are you referring to the stress-energy tensor?

Einstein's "second mass/energy equation" can be found in "Out of My
Later Years" in the last chapter on science, in it.

It's all the buzz words, reduced to reflections on canon and modern-
day apologetics, part of foundations, contra "converting wall-papering
to grant-writing to wall-papering".

Doesn't sound very interesting to me.

Conformal mapping is about most representational as configuration
space to configuration space, about the manifold, and continuous
mappings, vis-a-vis twists and torsions, as we might read about in, "Rindler".

Sorry, but you're missing the point I was trying to make: The complex
variables concept has what are called "poles" -- regions that go to
infinity at particular points in the complex plane -- which cause
problems in analysis. The point is, mathematicians get "around" them
(pun intended).

Mathematics OWES physics, more and better physics of infinities, particularly continuous domains about the conceit of particles,
really.

I didn't know particles were conce[i]ted. Sounds like a lot of buzz
words to me.

A conceit, just means an abstract concesssion, not your high-falutin conceitedness,

You finally said something I didn't know. Did you mean definition 2:

"a fanciful expression in writing or speech; an elaborate metaphor:
'the idea of the wind's singing is a prime romantic conceit'"

If so, I just go by what is measured (except in this thread which is talking about the existence of FTL particles in the context of special relativity
and mass measurements of neutrinos.

Of course, it might help if you know that NIST CODATA provides the most current
measurements of fundamental particles their known quantities, and especially, that, every few years the small ones get smaller and the big ones bigger.

It's called "running constants", and about a "theory of sum potentials", which you
can wonder about as pondering the "path integral".

I'm more interested in the data that precedes that: the actual papers by those doing the experiments. And this thread began in the context of special relativity,
and GR complicates the discussion way too much

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Ross wrote:

Everybody has their own interests, I think that people not familiar with
"Out of My Later Years" don't know Einstein,

I watched Walter Isaacson's series. Maybe correct, but not too complinentary.

and without at least three definitions of continuous domains, don't know mathematics.

Mathematics is just about how to count.

Or at least the formalist foundations for analysis, generally.

Analysis is just counting correctly.

It's a continuum mechanics, ....

Which isn't the way the world is. Field theory is probably wrong, but it
works because the countable things are too small to matter very much.

The SI units these days are actually sort of tailored to keep SR simple.

The SI units preceded relativity. They were designed to make engineering simple.

All this is just prattling.

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On Friday, January 5, 2024 at 9:21:12 PM UTC-7, Ross Finlayson wrote:

On Friday, January 5, 2024 at 7:21:16 PM UTC-8, gharnagel wrote:

Ross wrote:

Everybody has their own interests, I think that people not familiar with "Out of My Later Years" don't know Einstein,

I watched Walter Isaacson's series. Maybe correct, but not too complimentary.

and without at least three definitions of continuous domains, don't know mathematics.

Mathematics is just about how to count.

Or at least the formalist foundations for analysis, generally.

Analysis is just counting correctly.

It's a continuum mechanics, ....

Which isn't the way the world is. Field theory is probably wrong, but it works because the countable things are too small to matter very much.

The SI units these days are actually sort of tailored to keep SR simple.

The SI units preceded relativity. They were designed to make engineering simple.

All this is just prattling.

Now maybe if the robot arm had to put in fifty cents for each game simulated, ....

Actually "counting" and "numbering" are two distinct, fundamental notions, with respect to numbers, with respect to integers, and magnitudes, and differences.

THIS is why you think you get the last word. I never said anything about "numbering" or robot arms, either. You drifted off in some random directions.

The SI units particularly of 2019 actually quite altogether slanted themselves
out, of various still practical empirical systems related muchly to the many lettered fields of electromagnetism, all one field, that are most useful in remote sensing, and the design of electronics.

That's strange. In getting my degree in electronic engineering, we used SI units
almost exclusively. You're drifting again.

If you think that "continuity isn't how the world works", I imagine you're one of those coat-tailing wall-paperists quite happy not having causality dictate determinism.

I don't see any connection between continuity and causality, except they both starts with c. Ooh, and that means the speed of light, so c also means that the world is not granular, and that starts with g, which means general relativity,
which is a continuous theory. So the speed of light means quantum theory is wrong because it posits the world has little indivisible things, but QFT fields are continuous, but ... and around the circle we go.

Einstein though, he is not.

"Out of My Later Years" has two parts, a personal beginning, a personal end, and science in the middle.

What you do is read it for the articles.

I'll pass, thank you.

Yeah if you're having problems with foundations of physics, then,
you might want to fix your problems in foundations of mathematics.

Ultraviolet catastrophe?

The problem was the wrong mathematics was applied to the real physics.

Infrared catastrophe.

???

About FTL now, the superluminal is widely observed in the sky survey.

Attribution without any detail, which would render the attribution void.

You know what isn't, though? Dark matter.

Yeah, if you look into neutrino physics, there's a lot going on,
and supersymmetry isn't dead, again.

I'm not so sure about SS. Maybe yes but probably no.

You know what else is used to keep engineering simple? Shut up and
compute.

Actually, that's what Mermin said about quantum mechanics. Engineers
are supposed to be smart enough to know when their calculations become unphysical.

Then double it.

Shut up twice? It's always a good idea to calculate twice.

Now, though I've exploited that it's kind of easy to make some humor at
the expense of someone just like you, please still consider that I consider it some kind of warm advice and that if you read my 10,000's posts and
watch my 100 hours, that you would be better informed both of the standard, and, the superclassical.

I'll pass, thank you.

Also you can read more my opinion in "Open Letter ..." to me, here.

Notice I mostly get the last word in, "sci.physics.relativity",
and that even practicing physicists warily observe it
being without contradiction.

As I said above, it's because you drift all over the place. Do you
have trouble staying focused?

Of course, only theoretical physicists have opinions,

Dead wrong, Ross. Only a few here are theoretical physicist, but
thear are many, many opinions :-))

experimental ones just have instructions.

Having been mostly in the experimental world, that's only partly true.
I've seen coworkers who think that A or B ought to be explored but were
told thou shalt not do A or B, thou shalt do C. And I've seen cases
where the engineer was given his head (well, some were handed their head,
too).

Warm regards
...

Is this the time that I say sayonara and let you have the last word? :-))

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On Saturday, January 6, 2024 at 5:34:23 PM UTC-7, Ross Finlayson wrote:

On Saturday, January 6, 2024 at 2:31:00 PM UTC-8, gharnagel wrote:

Is this the time that I say sayonara and let you have the last word? :-))

https://en.wikipedia.org/wiki/Faster-than-light

I guess it kind of depends whether you have an opinion, or take one.

“All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others.”
-- Douglas Adams

I "take" opinions after I test them and still consider they have some
validity.

“What I cannot create, I do not understand." -- Richard P. Feynman

The wiki article is a bit deficient. For example:

"Particles whose speed exceeds that of light (tachyons) have been hypothesized, but their existence would violate causality and would imply time travel."

Not necessarily so. That "opinion" is based on a perverted use of mathematics. The relativistic velocity composition equation, u' = (u - v)/(1 - uv/c^2), has a singularity at u = c^2/v. Infinities don't exist in the real world, so that means that the domain of applicability of the equation does not extend to that point or beyond it.

Moment and Motion: geometry and motion

https://www.youtube.com/watch?v=7E3zwENPiz0

I'll pass. I don't have time to spend an hour watching something I already know.

[buzz words deleted] geometry is motion.

Hmmm, that's a slippery one. Even though Gauss said:

“I am coming more and more to the conviction that the necessity of our geometry
cannot be demonstrated...geometry should be ranked, not with arithmetic, which is purely aprioristic, but with mechanics.” -- Carl Gauss, 1817


GR is interpreted in the sense of geometry, but I'm a bit skeptical of that. There are more ways to interprete the laws of physics than as geometry. It may be that "geometry as motion" is a bastardization of a noble branch of mathematics.

Just as proclaiming that FTL violates causality bastardizes SR.

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On Sunday, January 7, 2024 at 10:18:19 AM UTC-7, Ross Finlayson wrote:

On Sunday, January 7, 2024 at 6:47:49 AM UTC-8, gharnagel wrote:

On Saturday, January 6, 2024 at 5:34:23 PM UTC-7, Ross Finlayson wrote:

On Saturday, January 6, 2024 at 2:31:00 PM UTC-8, gharnagel wrote:

Is this the time that I say sayonara and let you have the last word? :-))

https://en.wikipedia.org/wiki/Faster-than-light

I guess it kind of depends whether you have an opinion, or take one.

“All opinions are not equal. Some are a very great deal more robust, sophisticated and well supported in logic and argument than others.”
-- Douglas Adams

I "take" opinions after I test them and still consider they have some validity.

“What I cannot create, I do not understand." -- Richard P. Feynman

The wiki article is a bit deficient. For example:

"Particles whose speed exceeds that of light (tachyons) have been hypothesized,
but their existence would violate causality and would imply time travel."

Not necessarily so. That "opinion" is based on a perverted use of mathematics.
The relativistic velocity composition equation, u' = (u - v)/(1 - uv/c^2), has
a singularity at u = c^2/v. Infinities don't exist in the real world, so that
means that the domain of applicability of the equation does not extend to that
point or beyond it.

Moment and Motion: geometry and motion

https://www.youtube.com/watch?v=7E3zwENPiz0

I'll pass. I don't have time to spend an hour watching something I already know.

[buzz words deleted] geometry is motion.

Hmmm, that's a slippery one. Even though Gauss said:

“I am coming more and more to the conviction that the necessity of our geometry
cannot be demonstrated...geometry should be ranked, not with arithmetic, which
is purely aprioristic, but with mechanics.” -- Carl Gauss, 1817

GR is interpreted in the sense of geometry, but I'm a bit skeptical of that.
There are more ways to interprete the laws of physics than as geometry. It may
be that "geometry as motion" is a bastardization of a noble branch of mathematics.

Just as proclaiming that FTL violates causality bastardizes SR.

Hm, you're smarter than the average person.

Flattery will get you everywhere.

Galilean linear motion doesn't imply closed time-like curves, no.

Drifting again. Not talking about Galilean relativity nor GR.

I sort of enjoy this now what seems coming up as your opinion
and your quoted sources and a scientific approach.

It's like when I think about my (distant) cousin Renatus DesCartes,
I'm like, yeah, kind of thinks.

The Wikipedia article that was about supraluminal motion
that now redirects to a snippet in "FTL concepts",
has that indeed it is apparent superluminal motion.

Anyways I'd encourage you to go on on this manner,
helping display your aspects of what we call "Einstein's
model physicist" and "Einstein's model philosopher",
then that really if you want to get Einstein's last word,
he wrote it in "Out of My Later Year", and, I read it,
for example in those videos reading it out.

Mathematics _owes_ physics more and better mathematics of real infinity.
This is primarily couched in definitions of continuity.
Everybody knows at least one, Dedekind's, but there's also Aristotle's,
and Nyquist/Shannon's, and Duns Scotus/Spinoza's, and du Bois-Reymond's.
This is for Euclid and Poincare, not Euclid and not-Euclid.

The practice of plagiarism is a fraud, twice.

Drifting ... drifting ... drifting

Anyways it's better your style in this manner,
then you should know your foundations of mathematics
if you expect to have a good foundations of physics,
mathematical physics.

I have a pretty good foundation in engineering, mathematics and physics.
Both in schooling and career -- but both a bit long of tooth. How about
you?

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