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Jan 29, 2008, 1:52:36 PM1/29/08

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The FAQ claims that there are no direct tests of length contraction.

I may have found one:

I may have found one:

Jan 29, 2008, 5:23:26 PM1/29/08

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xxein: Grasping at straws.

I remember a common (in space perhaps) observation that supports LC.

Perhaps a reader can cite.

I don't need a proof for myself. Any comprehensive, logical theory

discovers this as a necessary resultant. But it is still

misunderstood by most all theories.

Jan 29, 2008, 9:16:25 PM1/29/08

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Dear Dono:

"Dono" <sa...@comcast.net> wrote in message

news:7626d732-81e0-4e16...@i29g2000prf.googlegroups.com...

> The FAQ claims that there are no direct tests of

> length contraction. I may have found one:

>

> http://prola.aps.org/abstract/PRL/v75/i7/p1372_1

http://physics.weber.edu/schroeder/mrr/MRRtalk.html

... nothing to measure in magnetism *except* length contraction,

because the charge is known...

David A. Smith

Jan 29, 2008, 9:23:48 PM1/29/08

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On Jan 29, 6:16 pm, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>

wrote:

wrote:

This is a very bad article. Hans de Vries completely rewrote this

article . He does not use length contraction in his explanation . See

here:

http://chip-architect.com/news/2007_02_27_Magnetism_as_a_Relativistic_side_effect.html

Click on the pdf.

Jan 29, 2008, 9:34:27 PM1/29/08

to

Dear Dono:

"Dono" <sa...@comcast.net> wrote in message

news:d88cc742-f703-4ba7...@y5g2000hsf.googlegroups.com...

> On Jan 29, 6:16 pm, "N:dlzc D:aol T:com \(dlzc\)"

> <dl...@cox.net>

> wrote:

>> Dear Dono:

>>

>> "Dono" <sa...@comcast.net> wrote in message

>>

>> news:7626d732-81e0-4e16...@i29g2000prf.googlegroups.com...

>>

>> > The FAQ claims that there are no direct tests of

>> > length contraction. I may have found one:

>>

>> >http://prola.aps.org/abstract/PRL/v75/i7/p1372_1

>>

>> http://physics.weber.edu/schroeder/mrr/MRRtalk.html

>> ... nothing to measure in magnetism *except* length

>> contraction, because the charge is known...

>

> This is a very bad article. Hans de Vries completely

> rewrote this article . He does not use length contraction

> in his explanation . See here:

>

> http://chip-architect.com/news/2007_02_27_Magnetism_as_a_Relativistic_side_effect.html

>

> Click on the pdf.

Yes, he says it is length contraction. "A relativistic side

effect..." What he is doing is generalizing the mathematics from

what Purcell did.

David A. Smith

Jan 29, 2008, 9:38:06 PM1/29/08

to

On Jan 29, 6:34 pm, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>

wrote:

> Dear Dono:

>

> "Dono" <sa...@comcast.net> wrote in message

>

> news:d88cc742-f703-4ba7...@y5g2000hsf.googlegroups.com...

>

>

>

> > On Jan 29, 6:16 pm, "N:dlzc D:aol T:com \(dlzc\)"

> > <dl...@cox.net>

> > wrote:

> >> Dear Dono:

>

> >> "Dono" <sa...@comcast.net> wrote in message

>

> >>news:7626d732-81e0-4e16...@i29g2000prf.googlegroups.com...

>

> >> > The FAQ claims that there are no direct tests of

> >> > length contraction. I may have found one:

>

> >> >http://prola.aps.org/abstract/PRL/v75/i7/p1372_1

>

> >>http://physics.weber.edu/schroeder/mrr/MRRtalk.html

> >> ... nothing to measure in magnetism *except* length

> >> contraction, because the charge is known...

>

> > This is a very bad article. Hans de Vries completely

> > rewrote this article . He does not use length contraction

> > in his explanation . See here:

>

> >http://chip-architect.com/news/2007_02_27_Magnetism_as_a_Relativistic...

>

> > Click on the pdf.

>

> Yes, he says it is length contraction. "A relativistic side

> effect..." What he is doing is generalizing the mathematics from

> what Purcell did.

>

> David A. Smith

wrote:

> Dear Dono:

>

> "Dono" <sa...@comcast.net> wrote in message

>

> news:d88cc742-f703-4ba7...@y5g2000hsf.googlegroups.com...

>

>

>

> > On Jan 29, 6:16 pm, "N:dlzc D:aol T:com \(dlzc\)"

> > <dl...@cox.net>

> > wrote:

> >> Dear Dono:

>

> >> "Dono" <sa...@comcast.net> wrote in message

>

> >>news:7626d732-81e0-4e16...@i29g2000prf.googlegroups.com...

>

> >> > The FAQ claims that there are no direct tests of

> >> > length contraction. I may have found one:

>

> >> >http://prola.aps.org/abstract/PRL/v75/i7/p1372_1

>

> >>http://physics.weber.edu/schroeder/mrr/MRRtalk.html

> >> ... nothing to measure in magnetism *except* length

> >> contraction, because the charge is known...

>

> > This is a very bad article. Hans de Vries completely

> > rewrote this article . He does not use length contraction

> > in his explanation . See here:

>

>

> > Click on the pdf.

>

> Yes, he says it is length contraction. "A relativistic side

> effect..." What he is doing is generalizing the mathematics from

> what Purcell did.

>

> David A. Smith

Hans' demonstration does not use length contraction, please read

carefully.

Jan 29, 2008, 11:08:51 PM1/29/08

to

Dear Dono:

"Dono" <sa...@comcast.net> wrote in message

news:6be333b9-75bd-4e7a...@k2g2000hse.googlegroups.com...

> Hans' demonstration does not use length contraction,

> please read carefully.

Read again. Started with a particle with a velocity, and got a

net charge density change. Length contraction. Since length

contraction and time dilation are two sides of the same coin, he

also arrives (explicity) at time dilation.

Choose your weapons, but they are all the same.

David A. Smith

Jan 29, 2008, 11:34:36 PM1/29/08

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On Jan 29, 11:08 pm, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>> David A. Smith- Hide quoted text -

>

> - Show quoted text -

>

> - Show quoted text -

xxein: LC and TD are not two sides of the same coin. Their

dimensional aspects demand separation from such a physical and

mathematical construct.

Jan 29, 2008, 11:41:15 PM1/29/08

to

"xxein" <xx...@comcast.net> wrote in message

news:cd819dcb-7c24-4aac...@v67g2000hse.googlegroups.com...

news:cd819dcb-7c24-4aac...@v67g2000hse.googlegroups.com...

Well .. in one sense they are .. in that they need to go together .. along

with relativity of simultaneity. If you have one without the others, then

things fall apart and make no sense. Many anti-relativists fall into that

trap. Basically all three are results of minkowski space / lorentz

transforms .. that is the 'coin' that they can be considered 'sides' of.

Jan 30, 2008, 12:00:24 AM1/30/08

to

Dear xxein:

"xxein" <xx...@comcast.net> wrote in message

news:cd819dcb-7c24-4aac...@v67g2000hse.googlegroups.com...

...

> xxein: LC and TD are not two sides of the

> same coin. Their dimensional aspects

> demand separation from such a physical and

> mathematical construct.

We see the lifetime of the muon "time dilated". The muon sees

our atmosphere as "length contracted" to a few tens of meters,

and its lifetime unaffected.

Same coin, two sides.

David A. Smith

Jan 30, 2008, 12:01:19 AM1/30/08

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On Jan 29, 8:08 pm, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>

I read it several times , perhaps you will care to point out the exact

formula where Hans invokes length contraction. They are numbered, so

it should be easy.

Jan 30, 2008, 8:22:21 AM1/30/08

to

Dear Dono:

"Dono" <sa...@comcast.net> wrote in message

news:0a4c7819-a92c-4bcd...@l32g2000hse.googlegroups.com...

> I read it several times , perhaps you will care to point out

> the exact formula where Hans invokes length contraction.

> They are numbered, so it should be easy.

between (1) and (2), and shown in Figure 1.

He handwaves at equations (2), and notes that he likes the shape

of the time dilation formula, because it has the exact term

(v/c^2) that he is looking for. When the length contraction

formula does also:

x = gamma * (x' - vt') equates to ...

(gamma * x' - x) / (t' * c^2) = v / c^2

... now compare that to the resultant of his (1)

qL / I = v / c^2

It is the same coin, Dono. It has *two* sides. One is length

contraction, the other time dilation.

David A. Smith

Jan 30, 2008, 10:16:37 AM1/30/08

to

On Jan 30, 5:22 am, "N:dlzc D:aol T:com \(dlzc\)" <dl...@cox.net>

This is relativity of simulatneity, all right. Note his title as well.

You are wasting my time (and yours)

Jan 30, 2008, 5:06:44 PM1/30/08

to

"Dono" <sa...@comcast.net> wrote in message

news:978fe97d-2b98-464b...@v67g2000hse.googlegroups.com...I agree with Dono .. the analysis does not make use of length contraction

per-se. One could possibly say that if one is using one part of the Lorentz

transform, one must be using all of it, so implicitly it is using length

contraction .. but that's not a direct use (as is what appears to have been

claimed).

Feb 2, 2008, 8:03:22 AM2/2/08

to

I disagree with their analysis and claims, and do not consider this to

be truly Lorentz contraction. That's because their factor is

sqrt(1-v^2/cbar^2) where cbar is the speed of light in their junction

(about 0.05 c). True Lorentz contraction involves the vacuum speed of

light, c, not cbar. I consider this an electromagnetic phenomenon that

uses a formula similar to Lorentz contraction, and not Lorentz

contraction itself. This is supported by their entire approach, which is

based on wave equations in the junction -- clearly electromagnetic

phenomena, and not the underlying structure of spacetime -- their wave

equation is NOT Lorentz invariant, as it inherently involves a special

frame, the rest frame of the junction.

The local structure of spacetime is related to c (the invariant speed of

the Lorentz transform), not any electromagnetic properties of materials

or optical media. Lorentz contraction is related to the structure of

spacetime, not any materials or media.

Tom Roberts

Feb 2, 2008, 10:10:59 AM2/2/08

to

On Feb 2, 3:03 pm, Tom Roberts <tjroberts...@sbcglobal.net> wrote in

sci.physics.relativity:

sci.physics.relativity:

But Roberts Roberts this contradicts a recent breathtaking discovery

of yours that confirmed an earlier breathtaking discovery of Jean-Marc

Levy-Leblond:

Tom Roberts' breathtaking discovery: Even if "light in vacuum does not

travel at the invariant speed of the Lorentz transform", Special

Relativity "would be unaffected":

http://groups.google.ca/group/sci.physics.relativity/browse_frm/thread/8034dc146100e32c?

Tom Roberts, Feb 1, 2006: "If it is ultimately discovered that the

photon has a nonzero mass (i.e. light in vacuum does not travel at the

invariant speed of the Lorentz transform), SR would be unaffected but

both Maxwell's equations and QED would be refuted (or rather, their

domains of applicability would be reduced)."

http://o.castera.free.fr/pdf/chronogeometrie.pdf

Jean-Marc Levy-Leblond: "D'autre part, nous savons aujourd'hui que

l'invariance de la vitesse de la lumiere est une consequence de la

nullite de la masse du photon. Mais, empiriquement, cette masse, aussi

faible soit son actuelle borne superieure experimentale, ne peut et ne

pourra jamais etre consideree avec certitude comme rigoureusement

nulle. Il se pourrait meme que de futures mesures mettent en evidence

une masse infime, mais non-nulle, du photon ; la lumiere alors n'irait

plus a la "vitesse de la lumiere", ou, plus precisement, la vitesse de

la lumiere, desormais variable, ne s'identifierait plus a la vitesse

limite invariante. Les procedures operationnelles mises en jeu par le

"second postulat" deviendraient caduques ipso facto. La theorie elle-

meme en serait-elle invalidee ? Heureusement, il n'en est rien ; mais,

pour s'en assurer, il convient de la refonder sur des bases plus

solides, et d'ailleurs plus economiques. En verite, le "premier

postulat" suffit, a la condition de l'exploiter a fond."

http://o.castera.free.fr/pdf/onemorederivation.pdf

Jean-Marc Levy-Leblond: "This is the point of view from wich I intend

to criticize the overemphasized role of the speed of light in the

foundations of the special relativity, and to propose an approach to

these foundations that dispenses with the hypothesis of the invariance

of c....We believe that special relativity at the present time stands

as a universal theory discribing the structure of a common space-time

arena in which all fundamental processes take place....The evidence of

the nonzero mass of the photon would not, as such, shake in any way

the validity of the special relativity. It would, however, nullify all

its derivations which are based on the invariance of the photon

velocity."

Pentcho Valev

pva...@yahoo.com

Feb 3, 2008, 1:39:20 AM2/3/08

to

Good point.

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