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On length contraction

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  On length contraction kenseto <setoken@att.net> - 2015-12-05 07:55 -0800
    Re: On length contraction Maciej Woźniak <mlwozniak@wp.pl> - 2015-12-05 18:40 +0100
    Re: On length contraction kenseto <setoken@att.net> - 2015-12-05 15:49 -0800
    Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-05 22:39 -0600
      Re: On length contraction Maciej Woźniak <mlwozniak@wp.pl> - 2015-12-06 10:28 +0100
      Re: On length contraction alsor@interia.pl - 2015-12-06 05:40 -0800
        Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-06 09:03 -0600
          Re: On length contraction alsor@interia.pl - 2015-12-09 02:37 -0800
        Re: On length contraction fuller.david@hotmail.com - 2015-12-06 08:14 -0800
          Re: On length contraction fuller.david@hotmail.com - 2015-12-06 08:27 -0800
            Re: On length contraction fuller.david@hotmail.com - 2015-12-06 10:37 -0800
      Re: On length contraction kenseto <setoken@att.net> - 2015-12-06 06:21 -0800
        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-06 08:19 -0800
          Stephane Baune tries to correct Ken Shito and, in the process, embarrasses himself "Dono," <sa_ge@comcast.net> - 2015-12-07 08:35 -0800
    Re: On length contraction Thomas Heger <ttt_heg@web.de> - 2015-12-06 08:24 +0100
      Re: On length contraction Poutnik <poutnik4nntp@gmail.com> - 2015-12-06 08:41 +0100
      Re: On length contraction kenseto <setoken@att.net> - 2015-12-06 07:06 -0800
      Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-06 09:20 -0600
        Re: On length contraction Thomas Heger <ttt_heg@web.de> - 2015-12-06 21:43 +0100
          Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 09:46 -0600
      Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-06 15:09 -0600
        Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 09:49 -0600
    Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-06 08:10 -0800
      Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 10:01 -0600
        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-07 08:28 -0800
          Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-07 10:57 -0600
            Re: On length contraction mlwozniak@wp.pl - 2015-12-07 22:58 -0800
            Re: On length contraction Thomas Heger <ttt_heg@web.de> - 2015-12-08 08:44 +0100
            Re: On length contraction kenseto <setoken@att.net> - 2015-12-08 14:33 -0800
              Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-08 17:56 -0600
              Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-10 20:07 +0000
                Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 13:13 -0800
                  Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-10 17:19 -0600
                    Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-11 02:45 +0000
                      Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 21:11 -0800
                        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-11 06:57 -0800
                          Re: On length contraction kenseto <setoken@att.net> - 2015-12-11 19:20 -0800
                        Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-11 19:55 +0000
                          Re: On length contraction Plexippus Kritikos <plexik@laertesegidio.org> - 2015-12-11 23:25 +0000
                          Re: On length contraction kenseto <setoken@att.net> - 2015-12-11 19:25 -0800
                            Re: On length contraction pnalsing@gmail.com - 2015-12-11 19:48 -0800
                              Re: On length contraction pnalsing@gmail.com - 2015-12-13 14:33 -0800
                            Re: On length contraction moroney@world.std.spaamtrap.com (Michael Moroney) - 2015-12-12 17:27 +0000
                            Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-14 10:12 -0600
                    Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 21:08 -0800
                      Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-11 08:04 -0600
      Re: On length contraction kenseto <setoken@att.net> - 2015-12-08 14:26 -0800
        Re: On length contraction Plexippus Kritikos <plexik@laertesegidio.org> - 2015-12-08 22:40 +0000
          Re: On length contraction kenseto <setoken@att.net> - 2015-12-09 06:50 -0800
            Re: On length contraction alsor@interia.pl - 2015-12-09 09:06 -0800
        Re: On length contraction rotchm <rotchm@gmail.com> - 2015-12-09 09:47 -0800
          Re: On length contraction Plexippus Kritikos <plexik@laertesegidio.org> - 2015-12-09 18:11 +0000
            Re: On length contraction Sam Wormley <swormley1@gmail.com> - 2015-12-09 12:32 -0600
              Re: On length contraction alsor@interia.pl - 2015-12-09 11:18 -0800
              Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 06:57 -0800
          Re: On length contraction kenseto <setoken@att.net> - 2015-12-10 06:46 -0800
    Re: On length contraction wugi <brol@brol.be> - 2015-12-06 18:18 +0100
      Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-06 12:35 -0600
        Re: On length contraction wugi <brol@brol.be> - 2015-12-06 21:58 +0100
          Re: On length contraction wugi <brol@brol.be> - 2015-12-06 22:31 +0100
          Re: On length contraction Tom Roberts <tjroberts137@sbcglobal.net> - 2015-12-07 10:16 -0600
        Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 13:08 -0800
          Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 14:26 -0800
            Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 14:38 -0800
            Re: On length contraction John Gogo <jfgogo22@yahoo.com> - 2015-12-06 15:39 -0800
    Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-06 15:07 -0600
      Re: On length contraction benj <none@gmail.com> - 2015-12-14 02:21 -0500
        Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-14 10:44 -0600
          Re: On length contraction alsor@interia.pl - 2015-12-14 08:59 -0800
          Re: On length contraction kenseto <setoken@att.net> - 2015-12-14 09:05 -0800
            Re: On length contraction alsor@interia.pl - 2015-12-14 09:48 -0800
            Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-14 12:18 -0600
              Re: On length contraction kenseto <setoken@att.net> - 2015-12-15 05:49 -0800
                Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-15 08:21 -0600
                  Re: On length contraction mlwozniak@wp.pl - 2015-12-15 23:29 -0800
                  Re: On length contraction kenseto <setoken@att.net> - 2015-12-16 07:04 -0800
                    Re: On length contraction Odd Bodkin <bodkinodd@gmail.com> - 2015-12-16 09:14 -0600

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#371462 — On length contraction

On length contraction according to SR:
1. A meter stick M is moving wrt observers A, B and C.

2. A predicts (SRians claim "Measures") the contracted length of M is 1/gamma_am.

3. B predicts (SRians claim "Measures") the contracted length of M is 1/gamma_bm.

4. C predicts (SRians claim "Measures") the contracted length of M is 1/gamma_cm.

It is obvious that M cannot have different contracted material lengths as predicted by the different observers. That means that length contraction in SR is not material (not real). So what is length contraction in SR? SRians claim that length contraction is the geometric projection of the meter stick onto the x-axis of observer's coordinate system.

IRT provide a more logical explanation of the length contraction equation as follows:
1. A predicts that the light-path length of M is 1/gamma_am meters and A assumes that the light-path length of his meter stick is its material length.
2. B predicts that the light-path length of M is 1/gamma_bm meters and B assumes that the light-path length of his meter stick is its material length.
3. C predicts that the light-path length of M is 1/gamma_bm meters and C assumes that the light-path length of his meter stick is its material length.

These IRT predictions eliminate all the paradoxes of SR derived from the constant light speed postulate. A paper on IRT is available in the following link:
http://www.modelmechanics.org/2015irt.pdf

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#371464

Użytkownik "kenseto"  napisał w wiadomości grup 
dyskusyjnych:480b34d8-19e3-4189-a293-4cf298956389@googlegroups.com...

|On length contraction according to SR:

Well, relativistic morons admit, that it is only result of
using inproper measurement apparature. Nothing more.

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#371468

On Saturday, December 5, 2015 at 10:55:53 AM UTC-5, kenseto wrote:
> On length contraction according to SR:
> 1. A meter stick M is moving wrt observers A, B and C.
> 
> 2. A predicts (SRians claim "Measures") the contracted length of M is 1/gamma_am.
> 
> 3. B predicts (SRians claim "Measures") the contracted length of M is 1/gamma_bm.
> 
> 4. C predicts (SRians claim "Measures") the contracted length of M is 1/gamma_cm.
> 
> It is obvious that M cannot have different contracted material lengths as predicted by the different observers. That means that length contraction in SR is not material (not real). So what is length contraction in SR? SRians claim that length contraction is the geometric projection of the meter stick onto the x-axis of observer's coordinate system.
> 
> IRT provide a more logical explanation of the length contraction equation as follows:
> 1. A predicts that the light-path length of M is 1/gamma_am meters and A assumes that the light-path length of his meter stick is its material length.
> 2. B predicts that the light-path length of M is 1/gamma_bm meters and B assumes that the light-path length of his meter stick is its material length.
> 3. C predicts that the light-path length of M is 1/gamma_bm meters and C assumes that the light-path length of his meter stick is its material length.

Sorry.....C predicts that the light-path length of M is "1/gamma_cm".
> 
> These IRT predictions eliminate all the paradoxes of SR derived from the constant light speed postulate. A paper on IRT is available in the following link:
> http://www.modelmechanics.org/2015irt.pdf

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#371473

On 12/5/15 12/5/15   9:55 AM, kenseto wrote:
> [...]So what is length contraction in SR? [...]

In SR, "length contraction" is a GEOMETRICAL PROJECTION. So it does not affect 
the object in any way. Nonetheless it is "real" in the sense that it affects 
physical measurements. The "contracted" length is what an observer moving 
relative to the object is predicted to measure for its length; this is a 
geometrical projection -- in SR relative motion involves a difference in 
orientation (in the 4-d spacetime), which affects the projection.

BTW the same is true for "time dilation", and that has been measured zillions of 
times, with results accurately agreeing with the predictions of SR.

Note there are also zillions of indirect measurements of "length contraction". 
But at present we do not have technology to measure it directly.


	I have told you this literally dozens of times. As you are
	apparently unable to remember anything, you will remain
	confused and befuddled. And unaware of it. I suggest you
	find a hobby more suited to your abilities.


Tom Roberts

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#371478

Użytkownik "Tom Roberts"  napisał w wiadomości grup 
dyskusyjnych:8KKdnZMuCL9sJv7LnZ2dnUU7_82dnZ2d@giganews.com...

|physical measurements. The "contracted" length is what an observer moving
|relative to the object is predicted to measure for its length; this is a

Remember, however, that if observer decide to measure
"proper length" instead "length", he will get different result...

Let's praise the incredible wisdom of a relativistic moron. 

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#371481

W dniu niedziela, 6 grudnia 2015 05:39:17 UTC+1 użytkownik tjrob137 napisał:
> On 12/5/15 12/5/15   9:55 AM, kenseto wrote:
> > [...]So what is length contraction in SR? [...]
> 
> In SR, "length contraction" is a GEOMETRICAL PROJECTION. So it does not affect the object in any way.

Unfortunately, but such projection is impossible in the 3D space, babe.
> Nonetheless it is "real" in the sense that it affects
> physical measurements.
None of measurement can affect a physical quantity.
> The "contracted" length is what an observer moving
> relative to the object is predicted to measure for its length; this is a
> geometrical projection -- in SR relative motion involves a difference in
> orientation (in the 4-d spacetime), which affects the projection.
The contraction is real/physical, but unmeasurable in the SR framework convention.

> BTW the same is true for "time dilation",
> and that has been measured zillions of times,
> with results accurately agreeing with the predictions of SR.

In the experiments has been detected the clock-slow down effect only.
Never any time dilation, which is just an improvised at hoc term...
in the pseudoscience.

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#371485

On 12/6/15 12/6/15   7:40 AM, alsor@interia.pl wrote:
> W dniu niedziela, 6 grudnia 2015 05:39:17 UTC+1 użytkownik tjrob137 napisał:
>> On 12/5/15 12/5/15   9:55 AM, kenseto wrote:
>>> [...]So what is length contraction in SR? [...]
>> In SR, "length contraction" is a GEOMETRICAL PROJECTION. So it does not
>> affect the object in any way.
>
> Unfortunately, but such projection is impossible in the 3D space, babe.

But since we seem to live in a 4-D spacetime, it's OK. Note that the directly 
analogous measurement of "time dilation" has been performed zillions of times.


>> Nonetheless it is "real" in the sense that it affects physical
>> measurements.
> None of measurement can affect a physical quantity.

This depends only on the meanings of your words. Moreover, measurements of a 
quantum system CLEARLY do affect its physical state, so your claim is 
fundamentally wrong.

In SR neither "time dilation" nor "length contraction" affect the object itself, 
yet they can AND DO have physical consequences. One consequence of "time 
dilation" is the existence of pion beams almost a kilometer long. One 
consequence of "length contraction" is the magnetic force between 
current-carrying conductors; another is the agreement between differential 
cross-sections in fixed-target and colliding-beam experiments at the same 
center-of-mass energy.

	Geometrical projections often have physical consequences. For
	instance, a ladder can or can not be carried through a narrow
	doorway depending on the GEOMETRICAL PROJECTION of the ladder's
	length onto the doorway's width. Yet the ladder OBVIOUSLY is
	not itself "changed" by rotating it wrt the doorway.


> In the experiments has been detected the clock-slow down effect only. Never
> any time dilation, which is just an improvised at hoc term...

But that _IS_ what we mean by "time dilation". Again you focus on the meanings 
of words and not the underlying physical concepts. What really matters is 
agreement between measurements and the predictions of the theory -- the words 
one uses to describe the effect cannot possibly affect that.


Tom Roberts

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#371642

W dniu niedziela, 6 grudnia 2015 16:03:22 UTC+1 użytkownik tjrob137 napisał:
> > Unfortunately, but such projection is impossible in the 3D space, babe.
> 
> But since we seem to live in a 4-D spacetime, it's OK. Note that the directly 
> analogous measurement of "time dilation" has been performed zillions of times.

Your 4-D spacetime is simply a name of a space in the math sense,
so, your improvisation is fallacious, because that '4D spacetime'
is not the simple 4D geometric space - euclidean,
where distance is defined as: sqrt(dx^2+dy^2+dz^2+dw^2), but a quite different.

"time dilation" = a clock slow-down/speed-up.
 
> > None of measurement can affect a physical quantity.
> 
> This depends only on the meanings of your words. Moreover, measurements of a 
> quantum system CLEARLY do affect its physical state, so your claim is 
> fundamentally wrong.

The weird mind strongly affects the diablo activity... :)

 
> In SR neither "time dilation" nor "length contraction" affect the object itself,

Indeed... because there is no a bit of reality in the SR.
  
> > In the experiments has been detected the clock-slow down effect only. Never
> > any time dilation, which is just an improvised at hoc term...
> 
> But that _IS_ what we mean by "time dilation". Again you focus on the meanings 
> of words and not the underlying physical concepts. What really matters is 
> agreement between measurements and the predictions of the theory -- the words 
> one uses to describe the effect cannot possibly affect that.

No. Because the clock-slow down effect just implies: t = inv.
You don't understand the SR-model logics at all.

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#371493

> In SR, "length contraction" is a GEOMETRICAL PROJECTION. So it does not affect the object in any way. 

Unfortunately, but such projection is impossible in the 3D space, babe. 

When SR & GR are applied "in reality" that would seem to be not the case. 

As in water ice under pressure (non-relativistic) from Gravity (GR) will retain its liquid form at a lower temperature than ice not under pressure. 
As the electron shells are spatially compressed by gravitational pressure, the distance traveled is shortened raising the effective speed, causing an equivalent time dilation. 
More gravitational pressure = more photon per m^2 per second 

For the earth to keep the moon in orbit, The gravitational energy (joules) required to warp space time, if the moon were in physical contact as one unit (m1 * m2) to (1/mass^2) would become inverse square law for energy over distance, causing an effective decrease in the vacuum impedance of the system. 
Mass would become (Time)
Length contraction would become length dilation for the other party .... Mass causes space time through dilation. 

Energy / gravity
Conductance /  (1/ Impedance) 
Kinetic energy
Ke = (conductance - impedance)*m*v^2

http://www.indiana.edu/~minimal/archive/Triply/genus3/PLines/web/600b.png

Space (length^(-3*-2)) = 1/Time
Time = 1/Space (length^(-3*-2)
(-2)*(Space + Time) = 14D

14D - 11D = 3D spatially
14D -   3D = 11D temporally 


pi / (((3 * 10) / 14) + 1) = 0.9995976625

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#371495

http://www.indiana.edu/~minimal/archive/Triply/genus3/PLines/web/600b.png 

Space (length^(-3*-2)) = 1/Time 
Time = 1/Space (length^(-3*-2) 
(-2)*(Space + Time) = 14D 

14D - 11D = 3D spatially 
14D -   3D = 11D temporally 


pi / (((3 * 10) / 14) + 1) = 0.9995976625 

pi / (11*2)/(11-4) = 0.9995976625
11^2 + 4^2 = 137
137 * (11/4) = 376.75
1/((88/7) * 10^-7) * 376.75) = 299687500

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#371499

pi / (((3 * 10) / 14) + 1) = 0.9995976625

((29.96875 / 14) + 1) / pi = 0.99969198629

(1 / (88 / 7)) * 376.75 = 29.96875

376.75 / (88/7) = 29.96875

376.730313 / 376.75 = 0.99994774518

299792458 / 0.99994774518 = 299808347.842

1/0.99994774518 =  1.00005225755


1 - ((376.75^2) / 299 792 458) = 0.99952653724
pi/(22/7) = 0.9995976625

Horse shoes & hand grenades

2*10^-7  

The ampere is that constant current which, if maintained in two straight parallel conductors (Schwartz minimal surface = 4pi / 2)  of infinite length, of negligible circular cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2×10^-7 newton per meter of length.

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#371482

On Saturday, December 5, 2015 at 11:39:17 PM UTC-5, tjrob137 wrote:
> On 12/5/15 12/5/15   9:55 AM, kenseto wrote:
> > [...]So what is length contraction in SR? [...]
> 
> In SR, "length contraction" is a GEOMETRICAL PROJECTION. So it does not affect 
> the object in any way. 

So there is no material contraction....then there is no need for the bogus concept of relativity of simultaneity to explain the paradoxes of SR....right?

>Nonetheless it is "real" in the sense that it affects 
> physical measurements. 

No it is not real....it does not affect physcal measurements. It affects the light-path length of a moving meter stick.


>The "contracted" length is what an observer moving 
> relative to the object is predicted to measure for its length; this is a 
> geometrical projection -- in SR relative motion involves a difference in 
> orientation (in the 4-d spacetime), which affects the projection.
> 
> BTW the same is true for "time dilation", 

But a clock will accumulate less clock seconds after a journey. So that means that "time dilation" is real.


>and that has been measured zillions of 
> times, with results accurately agreeing with the predictions of SR.
> 
> Note there are also zillions of indirect measurements of "length contraction". 
> But at present we do not have technology to measure it directly.

That's because material length contraction is not real....the equation predicts the light-path length of a moving meter stick.

> 	I have told you this literally dozens of times. As you are
> 	apparently unable to remember anything, you will remain
> 	confused and befuddled. And unaware of it. I suggest you
> 	find a hobby more suited to your abilities.
> 
> 
> Tom Roberts

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#371494

On Sunday, December 6, 2015 at 9:21:54 AM UTC-5, kenseto wrote:

> So there is no material contraction....

SR never said so, nor otherwise. SR says that if you *measure* it, you will get this or that value.


> then there is no need for the bogus concept of relativity of 
> simultaneity to explain the paradoxes of SR....right?

Since there are no paradoxes [contradictions] in SR, RoS is not used to explain away the said paradoxes. 

> No it is not real....it does not affect physcal measurements. 

SR simply says that that if you *measure* it, you will get this or that value.
SR says " L = L/g". It says nothing about the very ambiguous expression "real".

> It affects the light-path length of a moving meter stick.

Another irrelevant expression. SR simply says that if you measure it you will get the value "L = Lo/g"


> But a clock will accumulate less clock seconds after a journey. 
> So that means that "time dilation" is real.

Irrelevant expressions. SR simply says that if you measure it, you will get the value "T = To/g". 

> That's because material length contraction is not real....

"because", "material length", "real" are all irrelevant words, and of which you dont understand their meanings. SR simply says that if you measure it, you will get the value "L = Lo/g". 

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#371543 — Stephane Baune tries to correct Ken Shito and, in the process, embarrasses himself

On Sunday, December 6, 2015 at 8:19:55 AM UTC-8, rotchm wrote:
> 
> SR says " L = L/g". It says nothing about the very ambiguous expression "real".
>

Stephane,

SR doesn't say the above imbecility. It is the idiot "rotchm" who says that.

 

> Irrelevant expressions. SR simply says that if you measure it, you will get the value "T = To/g". 
> 

Err, a second strike from the Stephane Baune pretender.

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#371475

Am 05.12.2015 16:55, schrieb kenseto:
> On length contraction according to SR:
> 1. A meter stick M is moving wrt observers A, B and C.
>
> 2. A predicts (SRians claim "Measures") the contracted length of M is 1/gamma_am.
>
> 3. B predicts (SRians claim "Measures") the contracted length of M is 1/gamma_bm.
>
> 4. C predicts (SRians claim "Measures") the contracted length of M is 1/gamma_cm.
>
> It is obvious that M cannot have different contracted material lengths as predicted by the different observers. That means that length contraction in SR is not material (not real). So what is length contraction in SR? SRians claim that length contraction is the geometric projection of the meter stick onto the x-axis of observer's coordinate system.
>

There is a circular definition hidden in the term 'length'.

The meter was once defined by a Platin-Iridum bar in Paris and was meant 
as 1/10000 of the distance from pole to equator.

This was a very pragmatic definition, but difficult to use, since copies 
of this bar were very expensive.

Then the speed of light was used to define length and a certain wave to 
measure time.

Now this is 'circular' and such a length could eventually shrink.

The reason is, that 'speed of light' (used in that definition) already 
contains length and time.

But we have in fact still this bar in Paris.

But could this material object shrink as well?

I would say: yes, it can vanish (in a black hole). After this 'length 
contraction' occurs.


TH

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#371476

Dne 06/12/2015 v 08:24 Thomas Heger napsal(a):
> 
> There is a circular definition hidden in the term 'length'.

It there is, you would not be able to tell how is 1 m long.
Like  y = 3.x,  x=y/3, how much is y ?
This is circular definition.
> 
> The meter was once defined by a Platin-Iridum bar in Paris and was meant 
> as 1/10000 of the distance from pole to equator.
> 
> This was a very pragmatic definition, but difficult to use, since copies 
> of this bar were very expensive.

No, it was abandoned because of low accuracy and long term drift,
limiting the measurements where the accuracy was already limited
just by accuracy of meter definition.

> 
> Then the speed of light was used to define length and a certain wave to 
> measure time.
> 
> Now this is 'circular' and such a length could eventually shrink.

It would be circular, if length, derived from light speed,
was than used to define light speed.
What is not the case.

Referring to the trivial example above,
there were used the first-like equation in past,
the second-like equation today,
but never both, to become circular.

> Now this is 'circular' and such a length could eventually shrink.

The meter standard rod was shrinking all the time.
It caused the light speed was slowly raising.

-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes great men humble, but small men arrogant.

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#371486

On Sunday, December 6, 2015 at 2:24:25 AM UTC-5, Thomas Heger wrote:
> Am 05.12.2015 16:55, schrieb kenseto:
> > On length contraction according to SR:
> > 1. A meter stick M is moving wrt observers A, B and C.
> >
> > 2. A predicts (SRians claim "Measures") the contracted length of M is 1/gamma_am.
> >
> > 3. B predicts (SRians claim "Measures") the contracted length of M is 1/gamma_bm.
> >
> > 4. C predicts (SRians claim "Measures") the contracted length of M is 1/gamma_cm.
> >
> > It is obvious that M cannot have different contracted material lengths as predicted by the different observers. That means that length contraction in SR is not material (not real). So what is length contraction in SR? SRians claim that length contraction is the geometric projection of the meter stick onto the x-axis of observer's coordinate system.
> >
> 
> There is a circular definition hidden in the term 'length'.
> 
> The meter was once defined by a Platin-Iridum bar in Paris and was meant 
> as 1/10000 of the distance from pole to equator.
> 
> This was a very pragmatic definition, but difficult to use, since copies 
> of this bar were very expensive.
> 
> Then the speed of light was used to define length and a certain wave to 
> measure time.
> 
> Now this is 'circular' and such a length could eventually shrink.
> 
> The reason is, that 'speed of light' (used in that definition) already 
> contains length and time.

The meter was redefined to be 1/299,792,458 light-seconds. This circular definition garantees the speed of light to be constant in all frames. 
For example: I can walk at the speed of c by redefine my walk-meter to be 1/299,792,458 walk-seconds.

> 
> But we have in fact still this bar in Paris.
> 
> But could this material object shrink as well?
> 
> I would say: yes, it can vanish (in a black hole). After this 'length 
> contraction' occurs.
> 
> 
> TH

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#371487

On 12/6/15 12/6/15   1:24 AM, Thomas Heger wrote:
> There is a circular definition hidden in the term 'length'.

No. The circularity is only in your personal misconceptions.


> The meter was once defined by a Platin-Iridum bar in Paris and was meant as
> 1/10000 of the distance from pole to equator.
> This was a very pragmatic definition, but difficult to use, since copies of this
> bar were very expensive.

And also there are implied uncertainties in every copy.


> Then the speed of light was used to define length and a certain wave to measure
> time.

You skipped the 1960 definition, based on the wavelength of light from a 
specific quantum transition in Krypton.

	This taught metrologists an important lesson: having an
	easily-reproducible standard is MUCH better than basing
	units on artifacts (such as the bar in Paris). They
	intend to apply this to all units in a proposed set of
	redefinitions for 2018, basing all units on defined
	values of physical constants. The most urgent is the
	definition of the kilogram, as the artifact in Paris
	is changing mass; it is also the unit for which
	errorbars in applying the definition are largest.


> Now this is 'circular' and such a length could eventually shrink.
> The reason is, that 'speed of light' (used in that definition) already contains
> length and time.

Not really. This depends on one's choice of base units. NATURE does not select 
any, so this is purely a HUMAN choice. There is nothing wrong in considering 
time and speed to be basic, rather than time and length.


> But we have in fact still this bar in Paris.
> But could this material object shrink as well?

It is OBSERVABLY changing length. There are several known processes that cause this.


> I would say: yes, it can vanish (in a black hole). After this 'length
> contraction' occurs.

That's downright silly, and COMPLETELY UNRELATED to the real issue: the FACT 
that the bar in Paris is changing length. Your statement also ignores the other 
reason for the redefinitions: the difficulty of applying the standard.


You REALLY should learn something about the subject before attempting to write 
about it. Your GUESSES are wrong.


Tom Roberts

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#371502

Am 06.12.2015 16:20, schrieb Tom Roberts:

>> But we have in fact still this bar in Paris.
>> But could this material object shrink as well?
>
> It is OBSERVABLY changing length. There are several known processes that
> cause this.

>> I would say: yes, it can vanish (in a black hole). After this 'length
>> contraction' occurs.
>
> That's downright silly, and COMPLETELY UNRELATED to the real issue: the
> FACT that the bar in Paris is changing length. Your statement also
> ignores the other reason for the redefinitions: the difficulty of
> applying the standard.

The bar in Paris is actually unrelated, (as is this nasty black hole in 
that bar.)

But length contraction does occur. Really, this is an observed fact!

>
> You REALLY should learn something about the subject before attempting to
> write about it. Your GUESSES are wrong.

Well, actually yes. But how should I prove experience?


TH

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#371538

On 12/6/15 12/6/15 - 2:43 PM, Thomas Heger wrote:
> But length contraction does occur. Really, this is an observed fact!

Sure. But why bring up irrelevancies? As I have said so often, "length 
contraction" does not affect the object, it only affects MEASUREMENTS OF MOVING 
OBJECTS. Nobody in their right mind would use moving objects in defining a unit 
of length, and certainly ISO did not.


>> You REALLY should learn something about the subject before attempting to
>> write about it. Your GUESSES are wrong.
>
> Well, actually yes. But how should I prove experience?

I don't know what "prove experience" means. But the way to learn about a subject 
is to STUDY it. That is, get books by knowledgeable authors and READ them. This 
is math and physics, so you MUST do the exercises, as that is the way to ensure 
you actually understand what you have read (i.e. "read with pencil in hand").

	For SR, I recommend:
		Taylor and Wheeler, _Spacetime_Physics_.
	For GR, start with:
		Geroch, _General_Relativity_From_A_to_B_.
	Then:
		Misner, Thorne, and Wheeler, _Gravitation_

After you have a basis in basic physics and relativity, you can venture into the 
literature for descriptions of metrology and other topics.


Tom Roberts

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