Clutterfreak wrote:

>> Clutterfreak wrote:
>>> Already since 1950s it became known that spherical objects, regardless
>>> of their speed relative to an observer, will look spherical to that
>>> observer.

Look is not the same as a coordinate transformation. It is the latter which
we refer to when we discuss "time dilation" and "length contraction".

> https://stuff.mit.edu/afs/athena/course/8/8.20/www/weisskopf.pdf

The official publication can be found here:

<https://physicstoday.scitation.org/doi/10.1063/1.3057105>

It cites Terrell’s paper:

<https://journals.aps.org/pr/abstract/10.1103/PhysRev.116.1041>

However, the rendering of “Terrell rotation” in the Wikipedia article on the
same lemma for speeds v ≈ c, which certainly is shortened as well, suggests
that Terrell/Weisskopf was/were wrong or at least carelessly imprecise when
they/he wrote

Terrell (abstract):

| Thus, for sufficiently small subtended solid angle, an object will appear—
| optically—the same shape to all observers. A sphere will photograph with
| precisely the same circular outline whether stationary or in motion with
| respect to the camera. […] Observers photographing the meter stick
| simultaneously from the same position will obtain precisely the same
| picture, except for a change in scale given by the Doppler shift ratio,
| irrespective of their velocity relative to the meter stick. Even if
| methods of measuring distance, such as stereoscopic photography, are used,
| the Lorentz contraction will not be visible, although correction for the
| finite velocity of light will reveal it to be present.

Weisskopf:

| A passenger in a fast space ship, looking out of the window, so it seemed
| to us, would see spherical objects contracted to ellipsoids. his is
| definitely not so according to Terrell's considerations, which for the
| special case of a sphere were also carried out by R. Penrose. […]
|
| […] In special relativity, this distortion has the remarkable effect of
| canceling the Lorentz contraction so that objects appear undistorted but
| only rotated. This is exactly true only for objects which subtend a small
| solid angle.

<https://en.wikipedia.org/wiki/Terrell_rotation>

See also:

<https://link.springer.com/article/10.1007/BF02895571>

| The two-dimensional projection (as in a photograph) of this distorted
| shape may coincide with that of the object (suitably rotated) at rest; but
| we emphasize that it would be grossly misleading to conclude from this, as
| is generally done in the literature, that distant relativistically moving
| objects appear as if simply [r]otated. […]

[I am not having the time to double-check this. However, multiple papers
have been published on that subject since then. I would be surprised if
not at least one refutes or clarifies Terrell’s/Weiskopf’s claim.
Strangely, though, no paper appears to have cited Weisskopf’s paper
according to the original publisher Physics Today, and Google Scholar,
though Terrell’s has been cited several times (those might be papers that
refute his).]

Further discussion should take place in sci.physics.relativity.

PointedEars
--
Q: What did the nuclear physicist order for lunch?
A: Fission chips.

(from: WolframAlpha)

On Wednesday, September 7, 2022 at 4:35:11 AM UTC-5, Thomas 'PointedEars' Lahn wrote:
> Clutterfreak wrote:
>
> >> Clutterfreak wrote:
> >>> Already since 1950s it became known that spherical objects, regardless
> >>> of their speed relative to an observer, will look spherical to that
> >>> observer.
>
> Look is not the same as a coordinate transformation. It is the latter which
> we refer to when we discuss "time dilation" and "length contraction".
>
> > https://stuff.mit.edu/afs/athena/course/8/8.20/www/weisskopf.pdf
>
> The official publication can be found here:
>
> <https://physicstoday.scitation.org/doi/10.1063/1.3057105>
>
> It cites Terrell’s paper:
>
> <https://journals.aps.org/pr/abstract/10.1103/PhysRev.116.1041>
>
> However, the rendering of “Terrell rotation” in the Wikipedia article on the
> same lemma for speeds v ≈ c, which certainly is shortened as well, suggests
> that Terrell/Weisskopf was/were wrong or at least carelessly imprecise when
> they/he wrote
>
> Terrell (abstract):
>
> | Thus, for sufficiently small subtended solid angle, an object will appear—
> | optically—the same shape to all observers. A sphere will photograph with
> | precisely the same circular outline whether stationary or in motion with
> | respect to the camera. […] Observers photographing the meter stick
> | simultaneously from the same position will obtain precisely the same
> | picture, except for a change in scale given by the Doppler shift ratio,
> | irrespective of their velocity relative to the meter stick. Even if
> | methods of measuring distance, such as stereoscopic photography, are used,
> | the Lorentz contraction will not be visible, although correction for the
> | finite velocity of light will reveal it to be present.
>
> Weisskopf:
>
> | A passenger in a fast space ship, looking out of the window, so it seemed
> | to us, would see spherical objects contracted to ellipsoids. his is
> | definitely not so according to Terrell's considerations, which for the
> | special case of a sphere were also carried out by R. Penrose. […]
> |
> | […] In special relativity, this distortion has the remarkable effect of
> | canceling the Lorentz contraction so that objects appear undistorted but
> | only rotated. This is exactly true only for objects which subtend a small
> | solid angle.
>
> <https://en.wikipedia.org/wiki/Terrell_rotation>
>
> See also:
>
> <https://link.springer.com/article/10.1007/BF02895571>
>
> | The two-dimensional projection (as in a photograph) of this distorted
> | shape may coincide with that of the object (suitably rotated) at rest; but
> | we emphasize that it would be grossly misleading to conclude from this, as
> | is generally done in the literature, that distant relativistically moving
> | objects appear as if simply [r]otated. […]
>
> [I am not having the time to double-check this. However, multiple papers
> have been published on that subject since then. I would be surprised if
> not at least one refutes or clarifies Terrell’s/Weiskopf’s claim.
> Strangely, though, no paper appears to have cited Weisskopf’s paper
> according to the original publisher Physics Today, and Google Scholar,
> though Terrell’s has been cited several times (those might be papers that
> refute his).]

I've been working on a 3D animation in my spare time.
(I don't seem to have very much spare time lately, so
don't expect it soon.)
The outline of a sphere remains circular, but the sphere
appears to be squashed and tilted. It's rather difficult to
understand on the basis of a strictly verbal description,
and a flat one-eyed view doesn't make things any more
clear. However, top-front-side projections can do a lot to
clarify what is going on; likewise a binocular view can help.

I don't see anything wrong with Terrell's description, the
only difficulty being that it is strictly verbal and hence
subject to misinterpretation.

On Wednesday, September 7, 2022 at 11:35:11 AM UTC+2, Thomas 'PointedEars' Lahn wrote:
> Clutterfreak wrote:
>
> >> Clutterfreak wrote:
> >>> Already since 1950s it became known that spherical objects, regardless
> >>> of their speed relative to an observer, will look spherical to that
> >>> observer.
>
> Look is not the same as a coordinate transformation. It is the latter which
> we refer to when we discuss "time dilation" and "length contraction".
>
> > https://stuff.mit.edu/afs/athena/course/8/8.20/www/weisskopf.pdf
>
> The official publication can be found here:
>
> <https://physicstoday.scitation.org/doi/10.1063/1.3057105>
>
> It cites Terrell’s paper:
>
> <https://journals.aps.org/pr/abstract/10.1103/PhysRev.116.1041>
>
> However, the rendering of “Terrell rotation” in the Wikipedia article on the
> same lemma for speeds v ≈ c, which certainly is shortened as well, suggests
> that Terrell/Weisskopf was/were wrong or at least carelessly imprecise when
> they/he wrote
>
> Terrell (abstract):
>
> | Thus, for sufficiently small subtended solid angle, an object will appear—
> | optically—the same shape to all observers. A sphere will photograph with
> | precisely the same circular outline whether stationary or in motion with
> | respect to the camera. […] Observers photographing the meter stick
> | simultaneously from the same position will obtain precisely the same
> | picture, except for a change in scale given by the Doppler shift ratio,
> | irrespective of their velocity relative to the meter stick. Even if
> | methods of measuring distance, such as stereoscopic photography, are used,
> | the Lorentz contraction will not be visible, although correction for the
> | finite velocity of light will reveal it to be present.
>
> Weisskopf:
>
> | A passenger in a fast space ship, looking out of the window, so it seemed
> | to us, would see spherical objects contracted to ellipsoids. his is
> | definitely not so according to Terrell's considerations, which for the
> | special case of a sphere were also carried out by R. Penrose. […]
> |
> | […] In special relativity, this distortion has the remarkable effect of
> | canceling the Lorentz contraction so that objects appear undistorted but
> | only rotated. This is exactly true only for objects which subtend a small
> | solid angle.
>
> <https://en.wikipedia.org/wiki/Terrell_rotation>
>
> See also:
>
> <https://link.springer.com/article/10.1007/BF02895571>
>
> | The two-dimensional projection (as in a photograph) of this distorted
> | shape may coincide with that of the object (suitably rotated) at rest; but
> | we emphasize that it would be grossly misleading to conclude from this, as
> | is generally done in the literature, that distant relativistically moving
> | objects appear as if simply [r]otated. […]

Not rotated but distorted in a certain way. This distortion is such that the
*outline* of an object with a circular outline will remain circular. But if the
surface of the object has some texture (a Picasso painting or something
on its surface) and is viewed stereoscopically, then the distortion will
be visible. This should be easy to demonstrate using computer graphics.

The circularity preservation comes from the fact that the transformation
from one observer's "visual sphere" to that of another observer is a
conformal map. Penrose calls it "sky mapping" and the general proof
of the conformality is IIRC in the first volume of his & Rindler's "Spinors
and Spacetime".

--
Jan

On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c...@gmail.com wrote:
>
> I've been working on a 3D animation in my spare time.
> (I don't seem to have very much spare time lately, so
> don't expect it soon.)
> The outline of a sphere remains circular, but the sphere
> appears to be squashed and tilted. It's rather difficult to
> understand on the basis of a strictly verbal description,
> and a flat one-eyed view doesn't make things any more
> clear. However, top-front-side projections can do a lot to
> clarify what is going on; likewise a binocular view can help.

It would be nice if you made stereo pairs (proximal, or cross-eyed,
please!) of that simulation. I don't think such images exist
on the web (meaning, in stereo). As for the image to paste
on the sphere, perhaps a simple "geographic" grid or
a Mona Lisa :-)

--
Jan

On Wednesday, September 7, 2022 at 10:23:34 AM UTC-7, JanPB wrote:
> On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c...@gmail.com wrote:
> >
> > I've been working on a 3D animation in my spare time.
> > (I don't seem to have very much spare time lately, so
> > don't expect it soon.)
> > The outline of a sphere remains circular, but the sphere
> > appears to be squashed and tilted. It's rather difficult to
> > understand on the basis of a strictly verbal description,
> > and a flat one-eyed view doesn't make things any more
> > clear. However, top-front-side projections can do a lot to
> > clarify what is going on; likewise a binocular view can help.
> It would be nice if you made stereo pairs (proximal, or cross-eyed,
> please!) of that simulation. I don't think such images exist
> on the web (meaning, in stereo). As for the image to paste
> on the sphere, perhaps a simple "geographic" grid or
> a Mona Lisa :-)
>
> --
> Jan

You are confused jan. Confused people are confusing...

Mitchell Raemsch

On Wednesday, September 7, 2022 at 2:35:11 AM UTC-7, Thomas 'PointedEars' Lahn wrote:
> Clutterfreak wrote:
>
> >> Clutterfreak wrote:
> >>> Already since 1950s it became known that spherical objects, regardless
> >>> of their speed relative to an observer, will look spherical to that
> >>> observer.
>
> Look is not the same as a coordinate transformation. It is the latter which
> we refer to when we discuss "time dilation" and "length contraction".
>
> > https://stuff.mit.edu/afs/athena/course/8/8.20/www/weisskopf.pdf
>
> The official publication can be found here:
>
> <https://physicstoday.scitation.org/doi/10.1063/1.3057105>
>
> It cites Terrell’s paper:
>
> <https://journals.aps.org/pr/abstract/10.1103/PhysRev.116.1041>
>
> However, the rendering of “Terrell rotation” in the Wikipedia article on the
> same lemma for speeds v ≈ c, which certainly is shortened as well, suggests
> that Terrell/Weisskopf was/were wrong or at least carelessly imprecise when
> they/he wrote
>
> Terrell (abstract):
>
> | Thus, for sufficiently small subtended solid angle, an object will appear—
> | optically—the same shape to all observers. A sphere will photograph with
> | precisely the same circular outline whether stationary or in motion with
> | respect to the camera. […] Observers photographing the meter stick
> | simultaneously from the same position will obtain precisely the same
> | picture, except for a change in scale given by the Doppler shift ratio,
> | irrespective of their velocity relative to the meter stick. Even if
> | methods of measuring distance, such as stereoscopic photography, are used,
> | the Lorentz contraction will not be visible, although correction for the
> | finite velocity of light will reveal it to be present.
>
> Weisskopf:
>
> | A passenger in a fast space ship, looking out of the window, so it seemed
> | to us, would see spherical objects contracted to ellipsoids. his is
> | definitely not so according to Terrell's considerations, which for the
> | special case of a sphere were also carried out by R. Penrose. […]
> |
> | […] In special relativity, this distortion has the remarkable effect of
> | canceling the Lorentz contraction so that objects appear undistorted but
> | only rotated. This is exactly true only for objects which subtend a small
> | solid angle.
>
> <https://en.wikipedia.org/wiki/Terrell_rotation>
>
> See also:
>
> <https://link.springer.com/article/10.1007/BF02895571>
>
> | The two-dimensional projection (as in a photograph) of this distorted
> | shape may coincide with that of the object (suitably rotated) at rest; but
> | we emphasize that it would be grossly misleading to conclude from this, as
> | is generally done in the literature, that distant relativistically moving
> | objects appear as if simply [r]otated. […]
>
> [I am not having the time to double-check this. However, multiple papers
> have been published on that subject since then. I would be surprised if
> not at least one refutes or clarifies Terrell’s/Weiskopf’s claim.
> Strangely, though, no paper appears to have cited Weisskopf’s paper
> according to the original publisher Physics Today, and Google Scholar,
> though Terrell’s has been cited several times (those might be papers that
> refute his).]
>
> Further discussion should take place in sci.physics.relativity.
>
>
> PointedEars
> --
> Q: What did the nuclear physicist order for lunch?
> A: Fission chips.
>
> (from: WolframAlpha)

Space contraction is ancient math science that does not exist.
It has never been measured and never will be...

Mitchell Raemsch

JanPB wrote:

> Not rotated but distorted in a certain way. This distortion is such that
> the *outline* of an object with a circular outline will remain circular.
> But if the surface of the object has some texture (a Picasso painting or
> something on its surface) and is viewed stereoscopically, then the
> distortion will be visible. This should be easy to demonstrate using
> computer graphics.

those "textures" are seemingly bas-reliefs, is a type of sculpture in a
wall surface. But you are a capitalist. For instance, a nato_member gives
100% security guaranties they will NEVER attack america or france. You
don't even know what you are paying 2% of your earned GDP for.

On Wednesday, September 7, 2022 at 12:23:34 PM UTC-5, JanPB wrote:
> On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c...@gmail.com wrote:
> >
> > I've been working on a 3D animation in my spare time.
> > (I don't seem to have very much spare time lately, so
> > don't expect it soon.)
> > The outline of a sphere remains circular, but the sphere
> > appears to be squashed and tilted. It's rather difficult to
> > understand on the basis of a strictly verbal description,
> > and a flat one-eyed view doesn't make things any more
> > clear. However, top-front-side projections can do a lot to
> > clarify what is going on; likewise a binocular view can help.
> It would be nice if you made stereo pairs (proximal, or cross-eyed,
> please!) of that simulation. I don't think such images exist
> on the web (meaning, in stereo). As for the image to paste
> on the sphere, perhaps a simple "geographic" grid or
> a Mona Lisa :-)

I came across an issue while trying to make a 3D animation.

If you could, with monocular vision, get distance information
to the various points of a sphere in rapid motion to the right,
you would "see" that the moving shape, although of circular
outline, is (ahem) "really" that of a flattened (Lorentz-
contracted) ellipsoid apparently viewed at an angle because
light from further points takes longer to reach your eye.

See figure 5 in "Visual appearance of wireframe objects in
special relativity" by Thomas Müller and Sebastian Boblest
Eur. J. Phys. 35 (2014) 065025

So one might expect that the shape when viewed from the
left eye should be broadened, while the shape when viewed from
the right eye should be narrowed. But that is not the case.
Both eyes see a circular outline.

The result is rather disturbing, like the creepy "eyes following you"
illusion exhibited by some paintings. Not to mention that I get a
bit of a headache. I'm not sure how to fix this.

On Monday, October 31, 2022 at 12:05:22 PM UTC+1, prokaryotic.c...@gmail.com wrote:
> On Wednesday, September 7, 2022 at 12:23:34 PM UTC-5, JanPB wrote:
> > On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c...@gmail.com wrote:
> > >
> > > I've been working on a 3D animation in my spare time.
> > > (I don't seem to have very much spare time lately, so
> > > don't expect it soon.)
> > > The outline of a sphere remains circular, but the sphere
> > > appears to be squashed and tilted. It's rather difficult to
> > > understand on the basis of a strictly verbal description,
> > > and a flat one-eyed view doesn't make things any more
> > > clear. However, top-front-side projections can do a lot to
> > > clarify what is going on; likewise a binocular view can help.
> > It would be nice if you made stereo pairs (proximal, or cross-eyed,
> > please!) of that simulation. I don't think such images exist
> > on the web (meaning, in stereo). As for the image to paste
> > on the sphere, perhaps a simple "geographic" grid or
> > a Mona Lisa :-)
> I came across an issue while trying to make a 3D animation.
>
> If you could, with monocular vision, get distance information
> to the various points of a sphere in rapid motion to the right,
> you would "see" that the moving shape, although of circular
> outline, is (ahem) "really" that of a flattened (Lorentz-
> contracted) ellipsoid apparently viewed at an angle because
> light from further points takes longer to reach your eye.

Yes.

> See figure 5 in "Visual appearance of wireframe objects in
> special relativity" by Thomas Müller and Sebastian Boblest
> Eur. J. Phys. 35 (2014) 065025

Looks interesting.

> So one might expect that the shape when viewed from the
> left eye should be broadened, while the shape when viewed from
> the right eye should be narrowed. But that is not the case.
> Both eyes see a circular outline.

Yes. Is the diameter of the outline the same for both eyes?

> The result is rather disturbing, like the creepy "eyes following you"
> illusion exhibited by some paintings. Not to mention that I get a
> bit of a headache. I'm not sure how to fix this.

:-)

--
Jan

On Monday, October 31, 2022 at 9:48:37 PM UTC-3, JanPB wrote:
> On Monday, October 31, 2022 at 12:05:22 PM UTC+1, prokaryotic.c...@gmail.com wrote:
> > On Wednesday, September 7, 2022 at 12:23:34 PM UTC-5, JanPB wrote:
> > > On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c...@gmail.com wrote:
> > > >
> > > > I've been working on a 3D animation in my spare time.
> > > > (I don't seem to have very much spare time lately, so
> > > > don't expect it soon.)
> > > > The outline of a sphere remains circular, but the sphere
> > > > appears to be squashed and tilted. It's rather difficult to
> > > > understand on the basis of a strictly verbal description,
> > > > and a flat one-eyed view doesn't make things any more
> > > > clear. However, top-front-side projections can do a lot to
> > > > clarify what is going on; likewise a binocular view can help.
> > > It would be nice if you made stereo pairs (proximal, or cross-eyed,
> > > please!) of that simulation. I don't think such images exist
> > > on the web (meaning, in stereo). As for the image to paste
> > > on the sphere, perhaps a simple "geographic" grid or
> > > a Mona Lisa :-)
> > I came across an issue while trying to make a 3D animation.
> >
> > If you could, with monocular vision, get distance information
> > to the various points of a sphere in rapid motion to the right,
> > you would "see" that the moving shape, although of circular
> > outline, is (ahem) "really" that of a flattened (Lorentz-
> > contracted) ellipsoid apparently viewed at an angle because
> > light from further points takes longer to reach your eye.
> Yes.
> > See figure 5 in "Visual appearance of wireframe objects in
> > special relativity" by Thomas Müller and Sebastian Boblest
> > Eur. J. Phys. 35 (2014) 065025
> Looks interesting.
> > So one might expect that the shape when viewed from the
> > left eye should be broadened, while the shape when viewed from
> > the right eye should be narrowed. But that is not the case.
> > Both eyes see a circular outline.
> Yes. Is the diameter of the outline the same for both eyes?
> > The result is rather disturbing, like the creepy "eyes following you"
> > illusion exhibited by some paintings. Not to mention that I get a
> > bit of a headache. I'm not sure how to fix this.
> :-)
>
> --
> Jan

Trying to "visualize" SR's Length Contraction can be harmful for your mental health, in particular
if you insist in thinking about electrons like "solid spheres".

You can try to assimilate the concepts of "longitudinal and traversal masses" that Lorentz conceived and Einstein plagiarized.

But, at least, Lorentz thought of electron's mass as being of "electromagnetic nature", mostly.

Heck, he even anticipated Einstein one year, as his formulae contains m = E/c2 (check it out. E is the energy of the electric field).

But, there is a conflict with "perceptions" of electrons in QFT: They are thought as "tiny propagating ripples of the quantum field".
And this perception of electrons as "energy blobs" is relativistic (Dirac).

Isn't physics marvelous? 10 different theories can live together overlapping, and nobody gets really crazy.

On Tuesday, November 1, 2022 at 7:09:12 AM UTC-7, Richard Hertz wrote:
> On Monday, October 31, 2022 at 9:48:37 PM UTC-3, JanPB wrote:
> > On Monday, October 31, 2022 at 12:05:22 PM UTC+1, prokaryotic.c...@gmail.com wrote:
> > > On Wednesday, September 7, 2022 at 12:23:34 PM UTC-5, JanPB wrote:
> > > > On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c....@gmail.com wrote:
> > > > >
> > > > > I've been working on a 3D animation in my spare time.
> > > > > (I don't seem to have very much spare time lately, so
> > > > > don't expect it soon.)
> > > > > The outline of a sphere remains circular, but the sphere
> > > > > appears to be squashed and tilted. It's rather difficult to
> > > > > understand on the basis of a strictly verbal description,
> > > > > and a flat one-eyed view doesn't make things any more
> > > > > clear. However, top-front-side projections can do a lot to
> > > > > clarify what is going on; likewise a binocular view can help.
> > > > It would be nice if you made stereo pairs (proximal, or cross-eyed,
> > > > please!) of that simulation. I don't think such images exist
> > > > on the web (meaning, in stereo). As for the image to paste
> > > > on the sphere, perhaps a simple "geographic" grid or
> > > > a Mona Lisa :-)
> > > I came across an issue while trying to make a 3D animation.
> > >
> > > If you could, with monocular vision, get distance information
> > > to the various points of a sphere in rapid motion to the right,
> > > you would "see" that the moving shape, although of circular
> > > outline, is (ahem) "really" that of a flattened (Lorentz-
> > > contracted) ellipsoid apparently viewed at an angle because
> > > light from further points takes longer to reach your eye.
> > Yes.
> > > See figure 5 in "Visual appearance of wireframe objects in
> > > special relativity" by Thomas Müller and Sebastian Boblest
> > > Eur. J. Phys. 35 (2014) 065025
> > Looks interesting.
> > > So one might expect that the shape when viewed from the
> > > left eye should be broadened, while the shape when viewed from
> > > the right eye should be narrowed. But that is not the case.
> > > Both eyes see a circular outline.
> > Yes. Is the diameter of the outline the same for both eyes?
> > > The result is rather disturbing, like the creepy "eyes following you"
> > > illusion exhibited by some paintings. Not to mention that I get a
> > > bit of a headache. I'm not sure how to fix this.
> > :-)
> >
> > --
> > Jan
> Trying to "visualize" SR's Length Contraction can be harmful for your mental health, in particular
> if you insist in thinking about electrons like "solid spheres".
>
> You can try to assimilate the concepts of "longitudinal and traversal masses" that Lorentz conceived and Einstein plagiarized.
>
> But, at least, Lorentz thought of electron's mass as being of "electromagnetic nature", mostly.
>
> Heck, he even anticipated Einstein one year, as his formulae contains m = E/c2 (check it out. E is the energy of the electric field).
>
> But, there is a conflict with "perceptions" of electrons in QFT: They are thought as "tiny propagating ripples of the quantum field".
> And this perception of electrons as "energy blobs" is relativistic (Dirac).
>
> Isn't physics marvelous? 10 different theories can live together overlapping, and nobody gets really crazy.

WE can't see what is being accelerated. How would we know where the atom lands with more energy?

[Answering the question in the subject.]

Calculations in the lab frame of space charge effects in a (bunched)
particle accelerator get the wrong answer unless the "length
contraction" of the moving bunch is included [#]

Note this is "length contraction" and not "space shrinking". The former
is precisely defined in SR, while the latter is not well defined at all.

[#] I have actually done this in the particle simulation
program I have written, and compared the calculations
to both rigorous calculations using Lenard-Wiechert
potentials, and to measurements of actual beams.

Tom Roberts

On Tuesday, November 1, 2022 at 7:09:12 AM UTC-7, Richard Hertz wrote:
> On Monday, October 31, 2022 at 9:48:37 PM UTC-3, JanPB wrote:
> > On Monday, October 31, 2022 at 12:05:22 PM UTC+1, prokaryotic.c...@gmail.com wrote:
> > > On Wednesday, September 7, 2022 at 12:23:34 PM UTC-5, JanPB wrote:
> > > > On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c....@gmail.com wrote:
> > > > >
> > > > > I've been working on a 3D animation in my spare time.
> > > > > (I don't seem to have very much spare time lately, so
> > > > > don't expect it soon.)
> > > > > The outline of a sphere remains circular, but the sphere
> > > > > appears to be squashed and tilted. It's rather difficult to
> > > > > understand on the basis of a strictly verbal description,
> > > > > and a flat one-eyed view doesn't make things any more
> > > > > clear. However, top-front-side projections can do a lot to
> > > > > clarify what is going on; likewise a binocular view can help.
> > > > It would be nice if you made stereo pairs (proximal, or cross-eyed,
> > > > please!) of that simulation. I don't think such images exist
> > > > on the web (meaning, in stereo). As for the image to paste
> > > > on the sphere, perhaps a simple "geographic" grid or
> > > > a Mona Lisa :-)
> > > I came across an issue while trying to make a 3D animation.
> > >
> > > If you could, with monocular vision, get distance information
> > > to the various points of a sphere in rapid motion to the right,
> > > you would "see" that the moving shape, although of circular
> > > outline, is (ahem) "really" that of a flattened (Lorentz-
> > > contracted) ellipsoid apparently viewed at an angle because
> > > light from further points takes longer to reach your eye.
> > Yes.
> > > See figure 5 in "Visual appearance of wireframe objects in
> > > special relativity" by Thomas Müller and Sebastian Boblest
> > > Eur. J. Phys. 35 (2014) 065025
> > Looks interesting.
> > > So one might expect that the shape when viewed from the
> > > left eye should be broadened, while the shape when viewed from
> > > the right eye should be narrowed. But that is not the case.
> > > Both eyes see a circular outline.
> > Yes. Is the diameter of the outline the same for both eyes?
> > > The result is rather disturbing, like the creepy "eyes following you"
> > > illusion exhibited by some paintings. Not to mention that I get a
> > > bit of a headache. I'm not sure how to fix this.
> > :-)
> >
> > --
> > Jan
> Trying to "visualize" SR's Length Contraction can be harmful for your mental health, in particular
> if you insist in thinking about electrons like "solid spheres".

Nobody is talking about electrons here. Read the posts you answer.

> You can try to assimilate the concepts of "longitudinal and traversal masses" that Lorentz conceived and Einstein plagiarized.

Einstein didn't "plagiarize" anything, he simply showed how to obtain LORENTZ's
result by a different approach which he described in his paper.

> But, at least, Lorentz thought of electron's mass as being of "electromagnetic nature", mostly.

"At least"?

> Heck, he even anticipated Einstein one year, as his formulae contains m = E/c2 (check it out. E is the energy of the electric field).

Formulas are not everything. That's why there is "Schwarzschild radius" and
not "Laplace radius".

> But, there is a conflict with "perceptions" of electrons in QFT: They are thought as "tiny propagating ripples of the quantum field".

Relativity is a classical theory, like Newton's and Maxwell's, so naturally all
three are in conflict with quantum theories.

> And this perception of electrons as "energy blobs" is relativistic (Dirac).

"Energy blobs"?

> Isn't physics marvelous? 10 different theories can live together overlapping, and nobody gets really crazy.

Yes, we don't have a single theory that would cover everything.

--
Jan

On Wednesday, November 2, 2022 at 3:16:22 AM UTC-3, JanPB wrote:
> On Tuesday, November 1, 2022 at 7:09:12 AM UTC-7, Richard Hertz wrote:

<snip>

> > Trying to "visualize" SR's Length Contraction can be harmful for your mental health, in particular
> > if you insist in thinking about electrons like "solid spheres".
> Nobody is talking about electrons here. Read the posts you answer.

It applies to any charged particle, asshole. Lorentz didn't even dream about protons, etc. Electrons were the hype in that epoch.

<snip>

> > But, at least, Lorentz thought of electron's mass as being of "electromagnetic nature", mostly.
> "At least"?

Read Lorentz's 1904 paper, smartass.

> > Heck, he even anticipated Einstein one year, as his formulae contains m = E/c2 (check it out. E is the energy of the electric field).
> Formulas are not everything. That's why there is "Schwarzschild radius" and not "Laplace radius".

All the marks of a delusional, conflicting, deceiver relativist in the answer from above.

> > But, there is a conflict with "perceptions" of electrons in QFT: They are thought as "tiny propagating ripples of the quantum field".
> Relativity is a classical theory, like Newton's and Maxwell's, so naturally all three are in conflict with quantum theories.

> > And this perception of electrons as "energy blobs" is relativistic (Dirac).
> "Energy blobs"?

YES! No shape, no accepted "radius" except the classic radius of 10E-15 m, so can fit with E=mc2 and energy of electric field.

You are the most stupid and arrogant relativist here, Jan. You are beating Tom, the SW developer, which says too much.

Relativists are looking like Bolsonaro and Trump, unable to concede to any given truth.

On Wednesday, November 2, 2022 at 5:59:44 AM UTC-7, Richard Hertz wrote:
> On Wednesday, November 2, 2022 at 3:16:22 AM UTC-3, JanPB wrote:
> > On Tuesday, November 1, 2022 at 7:09:12 AM UTC-7, Richard Hertz wrote:
> <snip>
> > > Trying to "visualize" SR's Length Contraction can be harmful for your mental health, in particular
> > > if you insist in thinking about electrons like "solid spheres".
> > Nobody is talking about electrons here. Read the posts you answer.
> It applies to any charged particle, asshole. Lorentz didn't even dream about protons, etc. Electrons were the hype in that epoch.

Again, read the posts you are answering to before answering.

> <snip>
> > > But, at least, Lorentz thought of electron's mass as being of "electromagnetic nature", mostly.
> > "At least"?
> Read Lorentz's 1904 paper, smartass.

I did.

> > > Heck, he even anticipated Einstein one year, as his formulae contains m = E/c2 (check it out. E is the energy of the electric field).
> > Formulas are not everything. That's why there is "Schwarzschild radius" and not "Laplace radius".
> All the marks of a delusional, conflicting, deceiver relativist in the answer from above.

Stop talking nonsense. Again, that's why there is "Schwarzschild radius" and not "Laplace radius".
Formulas are not everything. Lorentz himself remarked in 1908 that Einstein saw something
he did not (namely, that what he (Lorentz) considered an "abstract time parameter" could be
considered real).

> > > But, there is a conflict with "perceptions" of electrons in QFT: They are thought as "tiny propagating ripples of the quantum field".
> > Relativity is a classical theory, like Newton's and Maxwell's, so naturally all three are in conflict with quantum theories.
>
> > > And this perception of electrons as "energy blobs" is relativistic (Dirac).
> > "Energy blobs"?
> YES! No shape, no accepted "radius" except the classic radius of 10E-15 m, so can fit with E=mc2 and energy of electric field.
>
> You are the most stupid and arrogant relativist here, Jan. You are beating Tom, the SW developer, which says too much.
>
> Relativists are looking like Bolsonaro and Trump, unable to concede to any given truth.

Gobbledygook.

--
Jan

On Thursday, 3 November 2022 at 08:41:33 UTC+1, JanPB wrote:

> Formulas are not everything. Lorentz himself remarked in 1908 that Einstein saw something
> he did not (namely, that what he (Lorentz) considered an "abstract time parameter" could be
> considered real).

Sorry, poor halfbrain, it can only be considered real
by brainwashed morons like you (and even some of you
don't). In the meantime, in the real reality, forbidden by
your bunch of idiots real GPS and TAI keep measuring
t'=t, just like all serious clocks always did.

On Thursday, September 8, 2022 at 9:13:26 PM UTC-7, mitchr...@gmail.com wrote:
> On Wednesday, September 7, 2022 at 2:35:11 AM UTC-7, Thomas 'PointedEars' Lahn wrote:
> > Clutterfreak wrote:
> >
> > >> Clutterfreak wrote:
> > >>> Already since 1950s it became known that spherical objects, regardless
> > >>> of their speed relative to an observer, will look spherical to that
> > >>> observer.
> >
> > Look is not the same as a coordinate transformation. It is the latter which
> > we refer to when we discuss "time dilation" and "length contraction".
> >
> > > https://stuff.mit.edu/afs/athena/course/8/8.20/www/weisskopf.pdf
> >
> > The official publication can be found here:
> >
> > <https://physicstoday.scitation.org/doi/10.1063/1.3057105>
> >
> > It cites Terrell’s paper:
> >
> > <https://journals.aps.org/pr/abstract/10.1103/PhysRev.116.1041>
> >
> > However, the rendering of “Terrell rotation” in the Wikipedia article on the
> > same lemma for speeds v ≈ c, which certainly is shortened as well, suggests
> > that Terrell/Weisskopf was/were wrong or at least carelessly imprecise when
> > they/he wrote
> >
> > Terrell (abstract):
> >
> > | Thus, for sufficiently small subtended solid angle, an object will appear—
> > | optically—the same shape to all observers. A sphere will photograph with
> > | precisely the same circular outline whether stationary or in motion with
> > | respect to the camera. […] Observers photographing the meter stick
> > | simultaneously from the same position will obtain precisely the same
> > | picture, except for a change in scale given by the Doppler shift ratio,
> > | irrespective of their velocity relative to the meter stick. Even if
> > | methods of measuring distance, such as stereoscopic photography, are used,
> > | the Lorentz contraction will not be visible, although correction for the
> > | finite velocity of light will reveal it to be present.
> >
> > Weisskopf:
> >
> > | A passenger in a fast space ship, looking out of the window, so it seemed
> > | to us, would see spherical objects contracted to ellipsoids. his is
> > | definitely not so according to Terrell's considerations, which for the
> > | special case of a sphere were also carried out by R. Penrose. […]
> > |
> > | […] In special relativity, this distortion has the remarkable effect of
> > | canceling the Lorentz contraction so that objects appear undistorted but
> > | only rotated. This is exactly true only for objects which subtend a small
> > | solid angle.
> >
> > <https://en.wikipedia.org/wiki/Terrell_rotation>
> >
> > See also:
> >
> > <https://link.springer.com/article/10.1007/BF02895571>
> >
> > | The two-dimensional projection (as in a photograph) of this distorted
> > | shape may coincide with that of the object (suitably rotated) at rest; but
> > | we emphasize that it would be grossly misleading to conclude from this, as
> > | is generally done in the literature, that distant relativistically moving
> > | objects appear as if simply [r]otated. […]
> >
> > [I am not having the time to double-check this. However, multiple papers
> > have been published on that subject since then. I would be surprised if
> > not at least one refutes or clarifies Terrell’s/Weiskopf’s claim.
> > Strangely, though, no paper appears to have cited Weisskopf’s paper
> > according to the original publisher Physics Today, and Google Scholar,
> > though Terrell’s has been cited several times (those might be papers that
> > refute his).]
> >
> > Further discussion should take place in sci.physics.relativity.
> >
> >
> > PointedEars
> > --
> > Q: What did the nuclear physicist order for lunch?
> > A: Fission chips.
> >
> > (from: WolframAlpha)
> Space contraction is ancient math science that does not exist.
> It has never been measured and never will be...
>
> Mitchell Raemsch

It kind of has been, the Stanford Linear Accelerator or SLAC,
kind of has established it's so.

Le 03/11/2022 à 08:58, Maciej Wozniak a écrit :
> On Thursday, 3 November 2022 at 08:41:33 UTC+1, JanPB wrote:
>
>> Formulas are not everything. Lorentz himself remarked in 1908 that Einstein saw
>> something
>> he did not (namely, that what he (Lorentz) considered an "abstract time
>> parameter" could be
>> considered real).
>
> Sorry, poor halfbrain, it can only be considered real
> by brainwashed morons like you (and even some of you
> don't). In the meantime, in the real reality, forbidden by
> your bunch of idiots real GPS and TAI keep measuring
> t'=t, just like all serious clocks always did.

You keep repeating the same thing, it becomes spam, and it's not very
productive.

R.H.

On Thursday, November 3, 2022 at 4:58:29 AM UTC-3, maluw...@gmail.com wrote:
> On Thursday, 3 November 2022 at 08:41:33 UTC+1, JanPB wrote:

> > Formulas are not everything. Lorentz himself remarked in 1908 that Einstein saw something he did not
>> (namely, that what he (Lorentz) considered an "abstract time parameter" could be considered real).

> Sorry, poor halfbrain, it can only be considered real
> by brainwashed morons like you (and even some of you
> don't). In the meantime, in the real reality, forbidden by
> your bunch of idiots real GPS and TAI keep measuring
> t'=t, just like all serious clocks always did.

And then, Hendrik Antoon Lorentz (born in 1853, and being 55 years OLD _ Nobel), knew that he was going to
lose the Lorentz-Einstein relativity contest, because the cretin was young (28) and had all the jewish community
supporting his relentless promotion of HIS relativity.

So Lorentz, a tired horse by then, BECAME the secretary of Einstein: He promoted further Einstein's relativity everywhere;
sent jewish students or young physicist to work with Einstein (from 1912 to 1914); was used as a proxy hub to relay data
to England (Eddington) and USA (Newcomb); supporter, as advisor to Einstein during 1915 and the rest of WWI, when he
was isolated at Berlin; heavily promoted GR after Eddington'd expedition, giving numerous press conferences in
1919 and 1920; I forgot that he brought Einstein to the 1911 Solvay's conference, introducing the cretin to most
of the figures of European physics (an iconic, eccentric star in the rise).

By 1920, Lorentz was 67 yo, and actively sucked Einstein's ass. WHY? Because Einstein HELP HIM to become FAMOUS,
but he KNEW that Lorentz Transforms made him "immortal worldwide", close to Einstein.

So one cretin (Lorentz) made a life partnership with the master cretin (Einstein).

He sold out for fame, money and privileges.

On Tuesday, November 1, 2022 at 9:48:38 PM UTC-7, Tom Roberts wrote:
> [Answering the question in the subject.]
>
> Calculations in the lab frame of space charge effects in a (bunched)
> particle accelerator get the wrong answer unless the "length
> contraction" of the moving bunch is included [#]
>
> Note this is "length contraction" and not "space shrinking". The former
> is precisely defined in SR, while the latter is not well defined at all.

Both are not real. If the atom length contractions it is a problem for space travel by its distortion from round.
That is rules it out. The universe does not shrink by a local movement either...

Mitchell Raemsch
>
> [#] I have actually done this in the particle simulation
> program I have written, and compared the calculations
> to both rigorous calculations using Lenard-Wiechert
> potentials, and to measurements of actual beams.
>
> Tom Roberts

On Monday, October 31, 2022 at 7:48:37 PM UTC-5, JanPB wrote:
> On Monday, October 31, 2022 at 12:05:22 PM UTC+1, prokaryotic.c...@gmail.com wrote:
> > On Wednesday, September 7, 2022 at 12:23:34 PM UTC-5, JanPB wrote:
> > > On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c...@gmail.com wrote:
> > > >
> > > > I've been working on a 3D animation in my spare time.
> > > > (I don't seem to have very much spare time lately, so
> > > > don't expect it soon.)
> > > > The outline of a sphere remains circular, but the sphere
> > > > appears to be squashed and tilted. It's rather difficult to
> > > > understand on the basis of a strictly verbal description,
> > > > and a flat one-eyed view doesn't make things any more
> > > > clear. However, top-front-side projections can do a lot to
> > > > clarify what is going on; likewise a binocular view can help.
> > > It would be nice if you made stereo pairs (proximal, or cross-eyed,
> > > please!) of that simulation. I don't think such images exist
> > > on the web (meaning, in stereo). As for the image to paste
> > > on the sphere, perhaps a simple "geographic" grid or
> > > a Mona Lisa :-)
> > I came across an issue while trying to make a 3D animation.
> >
> > If you could, with monocular vision, get distance information
> > to the various points of a sphere in rapid motion to the right,
> > you would "see" that the moving shape, although of circular
> > outline, is (ahem) "really" that of a flattened (Lorentz-
> > contracted) ellipsoid apparently viewed at an angle because
> > light from further points takes longer to reach your eye.
> Yes.
> > See figure 5 in "Visual appearance of wireframe objects in
> > special relativity" by Thomas Müller and Sebastian Boblest
> > Eur. J. Phys. 35 (2014) 065025
> Looks interesting.
> > So one might expect that the shape when viewed from the
> > left eye should be broadened, while the shape when viewed from
> > the right eye should be narrowed. But that is not the case.
> > Both eyes see a circular outline.
> Yes. Is the diameter of the outline the same for both eyes?
> > The result is rather disturbing, like the creepy "eyes following you"
> > illusion exhibited by some paintings. Not to mention that I get a
> > bit of a headache. I'm not sure how to fix this.
> :-)

I gave up on making a 3D animation. There is NO PROBLEM in creating
the animation from the viewpoint of an infinitely distant observer,
since the sphere looks precisely as if it were rotating. But to a
close-by observer, the views from the left and right eye present
visual cues that are not consistent with normal perspective, and
these contradictory visual cues are disturbing to a person like myself
who is highly sensitive to "virtual reality sickness" and avoids video
games, 3D movies, VR headsets etc.

My older daughter celebrated her 13th birthday at a Putt Putt mini golf.
She challenged me to a wide screen speed racer game. After the game,
I left the party and spent the rest of the birthday party hunched over the
toilet. When not directly facing the bowl, I rested my face against the
coolness of the porcelain. It's hard to explain to somebody who has
not experienced VR Sickness what makes a toilet bowl so attractive...

Anyhow, here is my NON-3D animation of a Terrell-rotated sphere:
https://commons.wikimedia.org/wiki/File:Terrell_Rotation_Sphere.gif

On 11/5/2022 7:29 PM, Prokaryotic Capase Homolog wrote:
> On Monday, October 31, 2022 at 7:48:37 PM UTC-5, JanPB wrote:
>> On Monday, October 31, 2022 at 12:05:22 PM UTC+1, prokaryotic.c...@gmail.com wrote:
>>> On Wednesday, September 7, 2022 at 12:23:34 PM UTC-5, JanPB wrote:
>>>> On Wednesday, September 7, 2022 at 6:08:52 PM UTC+2, prokaryotic.c...@gmail.com wrote:
>>>>>
>>>>> I've been working on a 3D animation in my spare time.
[...]

Using PovRay might be of service to you. You can use your personal
program to dump out a file that PovRay can read. Fun things can be created:

https://youtu.be/heEPwsraZm4

https://youtu.be/HwIkk9zENcg

https://youtu.be/DUG-qnkXTF8

https://youtu.be/iF75LSbzIVM

On Thursday, November 3, 2022 at 10:21:45 AM UTC-7, Richard Hertz wrote:
> On Thursday, November 3, 2022 at 4:58:29 AM UTC-3, maluw...@gmail.com wrote:
> > On Thursday, 3 November 2022 at 08:41:33 UTC+1, JanPB wrote:
>
> > > Formulas are not everything. Lorentz himself remarked in 1908 that Einstein saw something he did not
> >> (namely, that what he (Lorentz) considered an "abstract time parameter" could be considered real).
>
> > Sorry, poor halfbrain, it can only be considered real
> > by brainwashed morons like you (and even some of you
> > don't). In the meantime, in the real reality, forbidden by
> > your bunch of idiots real GPS and TAI keep measuring
> > t'=t, just like all serious clocks always did.
> And then, Hendrik Antoon Lorentz (born in 1853, and being 55 years OLD _ Nobel), knew that he was going to
> lose the Lorentz-Einstein relativity contest, because the cretin was young (28) and had all the jewish community
> supporting his relentless promotion of HIS relativity.

No, you see in those days being Jewish was NOT what it is today.
You were subject to quotas which would be illegal today. And
Einstein was not a "cretin", you are just being infantile when you
say this, just throwing a tantrum. It's silly.

> So Lorentz, a tired horse by then, BECAME the secretary of Einstein:

Keep dreaming. Your type will accept *antyhing*, any idiocy, as long
as it manages to keep ypour idioptic ego intact. Feh.

--
Jan

On Sunday, November 6, 2022 at 12:31:42 AM UTC-3, JanPB wrote:
> On Thursday, November 3, 2022 at 10:21:45 AM UTC-7, Richard Hertz wrote:

<snip>

> > And then, Hendrik Antoon Lorentz (born in 1853, and being 55 years OLD _ Nobel), knew that he was going to
> > lose the Lorentz-Einstein relativity contest, because the cretin was young (28) and had all the jewish community
> > supporting his relentless promotion of HIS relativity.
> No, you see in those days being Jewish was NOT what it is today.
> You were subject to quotas which would be illegal today. And
> Einstein was not a "cretin", you are just being infantile when you
> say this, just throwing a tantrum. It's silly.

I didn't understand what you meant by "quotas" in that epoch, which would be illegal today. Please clarify it for me.

Plus, in that epoch, zionist movement was in the rise (Jewish and Christians that sided with the chosenites). Today, after WWI
and WWII, the control of the world by the cabal is complete (Schwab, NWO, etc,). It comprehends banking, MSM, NATO, Academia,
social movements. And it's accelerating by design since 2006, curiously with the explosion of social media and gullible people
in the west under almost absolute control and total profiling. If you fart, it can be geolocated and the person identified by Smell-ID.
Far above face recognition. Did you hear about WEF and its projects?

JanPB wrote:

> On Thursday, November 3, 2022 at 10:21:45 AM UTC-7, Richard Hertz wrote:
>> Nobel), knew that he was going to lose the Lorentz-Einstein relativity
>> contest, because the cretin was young (28) and had all the jewish
>> community supporting his relentless promotion of HIS relativity.
>
> No, you see in those days being Jewish was NOT what it is today.
> You were subject to quotas which would be illegal today. And Einstein
> was not a "cretin", you are just being infantile when you say this, just
> throwing a tantrum. It's silly.

wow, cacapitalist cacamerica gotten tire of the gay actor, khazar on
cocaine zelenske, said "president" with no party, hence no politics, hence
zero military experience. Just imagine how many tons of money this gay
actor madrefaka got for being gay, as "president" in a capitalist oligarch
nazi factitious, not existent, country. Capitalist europe poor like shit,
the gay zelenske felt with money.