### 1 Re: SR is succesfully debunked, spread the word.

Van: "Robert J. Kolker"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 28 augustus 2002 20:54

josX wrote:

 > Both is true. There are no prediction coming from SR really because it is a paradoxical theory, which only produces conflictiing predictions.

Mathematically SR is a theory of invariants under the Lorentz group. Examined independtly of whether it predicts correctly (i.e. its soundness), it is precisely as consistent as the theory of real variables under all topological groups defined on the the reals.

So if SR is inconsistent (internally) so the rest of real variable mathematics which takes down all of physics.

The only way to take down SR is to show one of its predictions is factually incorrect.

Bob Kolker

### 2 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zondag 1 september 2002 11:10

"Robert J. Kolker" schreef in bericht news:3D6D1C57.2050003@attbi.com...
 > Mathematically SR is a theory of invariants under the Lorentz group. Examined independtly of whether it predicts correctly (i.e. its soundness), it is precisely as consistent as the theory of real variables under all topological groups defined on the the reals. So if SR is inconsistent (internally) so the rest of real variable mathematics which takes down all of physics. The only way to take down SR is to show one of its predictions is factually incorrect.

I expect you mean: is experimental incorrect.

Theories are very often "based on" thought experiments.

Consider two points A and B at the same large distance R from an observer O.
The distance in the rest frame of O between the two points A and B is l
You move a rod with length l (in rest frame of O) starting left from A with high speed in straight line towards B. When front of rod reaches B "you" sent out a lightsignal.
When back of rod reaches A "you" sent out a lightsignal. Will the two lightsignals reach the observer simultaneous ?

When length contraction is involved IMO the answer is NO.

This is actual a good way IMO to demonstrate length contraction. Has such an experiment actual been performed ?

If the answer is No how would you (someone) propose an experiment to demonstrate length contraction.

The book Was Einstein Right (By Clifford M. Will) does (almost) not discuss length contraction except at page 273 under the subject Lorentz-FitzGerald contraction.
Here is written:
"On the other hand it is rather difficult effect to see experimentally because it is hard to accelerate macroscopic rods to high enough velocities to make the effect noticeable."

In the above thought experiment I wrote that the path between A and B is straight.
Consider that the path between A and B is slowly bended curved at is always a distance R from the observer.

Will there still be length contraction involved ?

The maximum is that the rod moves over a cirkel with radius R with markers a distance l apart ?

 > Bob Kolker

### 3 Re: SR is succesfully debunked, spread the word.

Van: "Robert J. Kolker"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zondag 1 september 2002 13:15

 > I expect you mean: is experimental incorrect.

Yes.

The chances of coming up with a mathematically based theory that is logically incosistent (or less consistent than the theory of real variables) is down in the noise. The way to break a theory is to show, by experiment, that one of its predictions is wrong and that the wrongness cannot be accounted for by an auxillary condition.

Example: The discoveries of Uranus. The visible planets did show a strange trajectory. Not what Newtonian gravity would predict. Is Newtonian gravity wrong? Or is there an auxillary condition like an unseen planet in the neigborhood.

When a theory mispredicts, the physicists have a lot of splainin' to do.

Bob Kolker

### 4 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zondag 1 september 2002 15:55

"Robert J. Kolker" schreef in bericht news:3D71F6EF.7030804@attbi.com...
 > Nicolaas Vroom wrote:
 > > I expect you mean: is experimental incorrect.
 > Yes.
SNIP
 > When a theory mispredicts, the physicists have a lot of splainin' to do.

When the predictions of a theory are not accordingly to the results of actual performed experiments ( by different experimentors) the theory is wrong.

But what if you can not (?) experimental demonstrate a theory ? As an example length contraction. See my previous posting

https://www.nicvroom.be/ See: Changing Length part 1 and part 2

Nick

### 5 Re: SR is succesfully debunked, spread the word.

Van: "Robert J. Kolker"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zondag 1 september 2002 15:59

 > But what if you can not (?) experimental demonstrate a theory ? As an example length contraction. See my previous posting

For things not directly demonstrable by experiment, you assume them as a hypothesis and test their -consequences- experimentally. If supported, you are safe for the day. If refuted the hypothesis goes down in flames.[1]

Bob Kolker

[1] Unless the discrepancy can be otherwise explained.

### 6 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: maandag 2 september 2002 23:05

"Robert J. Kolker" schreef in bericht news:3D721D71.9040007@attbi.com...
 > Nicolaas Vroom wrote:
 > > But what if you can not (?) experimental demonstrate a theory ? As an example length contraction. See my previous posting
 > For things not directly demonstrable by experiment, you assume them as a hypothesis and test their -consequences- experimentally. If supported, you are safe for the day. If refuted the hypothesis goes down in flames.

The issue under discussion is:
> Based on actual experiments: is SR correct, is SR wrong or state undecided.
To be more specific: Is length correction correct, wrong or undecided.

I suggested a way to test length contraction, Based on litterature (See previous post) it is not possible to test length contraction.

Using that same test (with an added observer in the middle of rod with length l) it is also possible (in principle) to demonstrate relativity of simultaneity (see Ray d' Inverno)
However because it is not possible to test length contraction it is also not possible to test Relativity of simultaneity.

Implying that both are still in experimental state as undecided.

It is interesting to know how different observers (in relative motion) would test that speed of light is c.
Can they perform such an test on earth ? Can they perform such a test using space (ie a planet)

Nick

### 7 Re: SR is succesfully debunked, spread the word.

Van: "Robert J. Kolker"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: dinsdag 3 september 2002 0:08

 > I suggested a way to test length contraction, Based on litterature (See previous post) it is not possible to test length contraction.

The number of muons makeing down to the test station on Mt. Washington test both length contraction and time dilation.

Bob Kolker

### 8 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: dinsdag 3 september 2002 7:59

"Robert J. Kolker" schreef in bericht news:3D73E17D.6010101@attbi.com...
 > Nicolaas Vroom wrote:
 > > I suggested a way to test length contraction, Based on litterature (See previous post) it is not possible to test length contraction.
 > The number of muons makeing down to the test station on Mt. Washington test both length contraction and time dilation.

Please supply the details. (IMO this experiment only tests time dilation) An url ? However be carefull. I did not ask for experimental results for time dilation. I asked for an experiment which demonstrates only length contraction. I also asked for an experiment which tests only relativity of simulataneity.

In addition I want to discuss how do you measure c by two different observers In addition I want to know if there still is length contraction when the path of the moving object is slightly bended.

Nick

### 9 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: dinsdag 3 september 2002 8:18

 > I did not ask for experimental results for time dilation. I asked for an experiment which demonstrates only length contraction. I also asked for an experiment which tests only relativity of simulataneity. In addition I want to discuss how do you measure c by two different observers In addition I want to know if there still is length contraction when the path of the moving object is slightly bended.

You have been posting on this group (sci.physics.relativity) for almost five years. Have you ever considered reading a text on the subject?

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 10 Re: SR is succesfully debunked, spread the word.

Van: "Jan C. Bernauer"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: dinsdag 3 september 2002 9:50

 > "Robert J. Kolker" schreef in bericht news:3D73E17D.6010101@attbi.com...
 >> Nicolaas Vroom wrote:
 >> > I suggested a way to test length contraction, Based on litterature (See previous post) it is not possible to test length contraction.
 >> The number of muons makeing down to the test station on Mt. Washington test both length contraction and time dilation.
 > Please supply the details. (IMO this experiment only tests time dilation) An url ?

You have to look at the experiment from the muons point of view. It doesnīt "see" itīs own time slowed, nor does it see the earth come in faster than light. No, it sees the distance to earth shortened!

 > However be carefull. I did not ask for experimental results for time dilation. I asked for an experiment which demonstrates only length contraction. I also asked for an experiment which tests only relativity of simulataneity.

I donīt think you can test these predictions without the other ones happening. They are like both sides of a coin.

----
Jan C. Bernauer

### 11 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: dinsdag 3 september 2002 22:35

"Jan C. Bernauer" schreef in bericht news:78q8nu8pn9vg353jiv4i2pucmtu1b63uum@4ax.com...
 > On Tue, 03 Sep 2002 05:59:57 GMT, "Nicolaas Vroom" wrote:
 > > "Robert J. Kolker" schreef in bericht news:3D73E17D.6010101@attbi.com...
 > >> Nicolaas Vroom wrote:
 > >> > I suggested a way to test length contraction, Based on litterature (See previous post) it is not possible to test length contraction.
 > >> The number of muons makeing down to the test station on Mt. Washington test both length contraction and time dilation.
 > > Please supply the details. (IMO this experiment only tests time dilation) An url ?
 > You have to look at the experiment from the muons point of view. It doesnīt "see" itīs own time slowed, nor does it see the earth come in faster than light. No, it sees the distance to earth shortened!

The book "Was Einstein Right" discusses at page 262 and 271 the muon. At page 271 is written: "The observational evidence for time dilation is overwelming... It is time dilation that slows down the decay rates of unstable muons generated by cosmic rays etc. "

Who do I have to believe ?

 >
 > > However be carefull. I did not ask for experimental results for time dilation. I asked for an experiment which demonstrates only length contraction. I also asked for an experiment which tests only relativity of simulataneity.
 > I donīt think you can test these predictions without the other ones happening. They are like both sides of a coin.

What you are claiming is that you can not perform any test which only demonstrates length contraction Nor can you perform any test which only test which only demonstrates relativity of simultaneity You can only perform tests which demonstrates both: length contraction and relativity of simultaneity together.

What is the description of this test ? Is this the Michelson-Morley experiment ?

Nick

### 12 Re: SR is succesfully debunked, spread the word.

Van: "MasterCougar"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 4 september 2002 3:45

On the dark and dreary 03 Sep 2002 Stephen Speicher posted news:Pine.GSO.4.42.0209022314390.9998- 100000@inky:

 > You have been posting on this group (sci.physics.relativity) for almost five years. Have you ever considered reading a text on the subject?

What and actually try to learn something about the subject?

--
Marc,
This is where I would normally put a funny sig, but now I just don't have it in me.

### 13 Re: SR is succesfully debunked, spread the word.

Van: "Randy Poe"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 4 september 2002 18:59

Nicolaas Vroom wrote:
 > "Jan C. Bernauer" schreef in bericht news:78q8nu8pn9vg353jiv4i2pucmtu1b63uum@4ax.com...
 > > On Tue, 03 Sep 2002 05:59:57 GMT, "Nicolaas Vroom" wrote:
 > > > "Robert J. Kolker" schreef in bericht news:3D73E17D.6010101@attbi.com...
 > > >> Nicolaas Vroom wrote:
 > > >> > I suggested a way to test length contraction, Based on litterature (See previous post) it is not possible to test length contraction.
 > > >> The number of muons makeing down to the test station on Mt. Washington test both length contraction and time dilation.
 > > > Please supply the details. (IMO this experiment only tests time dilation) An url ?
 > > You have to look at the experiment from the muons point of view. It doesnīt "see" itīs own time slowed, nor does it see the earth come in faster than light. No, it sees the distance to earth shortened!
 > The book "Was Einstein Right" discusses at page 262 and 271 the muon. At page 271 is written: "The observational evidence for time dilation is overwelming... It is time dilation that slows down the decay rates of unstable muons generated by cosmic rays etc. " Who do I have to believe ?

Both. The description of the same experiment from the earth's and the muon's point of view must lead to the same events.

From the earth point of view, muon time is dilated, and so it traverses a longer path during its lifetime.

The muon (or, equivalently, a spaceship travelling the same path at the same speed before the catastrophic collision with the earth at the end) would measure an unchanged lifetime. It would describe a contraction of the distance from outer atmosphere to ground.

 > What you are claiming is that you can not perform any test which only demonstrates length contraction Nor can you perform any test which only test which only demonstrates relativity of simultaneity You can only perform tests which demonstrates both: length contraction and relativity of simultaneity together.

Both happen together. If SR is correct, then you can't get one without the other. If you try, you'll get the contradictions that poor josX thinks he's seeing.

 > What is the description of this test ? Is this the Michelson-Morley experiment ?

Which test? This appears to be an alternate-physics textbook covering just about everything.

- Randy

### 14 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 4 september 2002 21:21

"Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209022314390.9998-100000@inky...
 > On Tue, 3 Sep 2002, Nicolaas Vroom wrote:
 > > I did not ask for experimental results for time dilation. I asked for an experiment which demonstrates only length contraction. I also asked for an experiment which tests only relativity of simulataneity. In addition I want to discuss how do you measure c by two different observers In addition I want to know if there still is length contraction when the path of the moving object is slightly bended.
 > You have been posting on this group (sci.physics.relativity) for almost five years. Have you ever considered reading a text on the subject?

Your reply gives the impression (?) that there are books which give the answers ? Where can I find the information about an experiment on length contraction ? "Was Einstein Right" tells that those tests are very difficult.

The document (mentioned dy Dirk VdM) http://physics.syr.edu/courses/PHY312.01Spring/MasterNotes.pdf discusses at page 72 the muon, but only to demonstrate time dilation and that is not what I want.

If you go to my home page you will find all the books that I have, but I do not think I will find there an answer on my questions.

How to measure c is for example described in the book "Einsteins Theory of Relativity" by Max Born at page 91-93. Those pages describe the methode used by Olaf Romer, where he uses the satelites of Jupiter. The question is if that method demonstrates the statement that the laws of physics are the same for all inertial observers.

Nick

### 15 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: donderdag 5 september 2002 6:07

 > "Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209022314390.9998-100000@inky...
 > > You have been posting on this group (sci.physics.relativity) for almost five years. Have you ever considered reading a text on the subject?

Indeed, that is so, which of course is the reason I suggested you read them. You might want to start with the recommended list in the FAQ, provided at URL

I also have an enormous personal library of books and papers about relativity, so if there is something specific you would like to study, please just ask.

 > Where can I find the information about an experiment on length contraction ?

Well, if you discount things such as relativistic bond length contractions, due to s and p orbital contractions, then you will not find any direct measurements of length contraction on a macroscopic scale. If you want to learn about some of the difficulties involved, you can start by reading James Terrell's classic paper, "Invisibility of the Lorentz Contraction," _Physical Review_, Volume 116, Number 4, November 15, 1959, pp. 1041-1045. If you want to see a more modern treatment, with references to some of the work inbetween, see "Projection of relativistically moving objects on a two-dimensional plane, the 'train' paradox and the visibility of the Lorentz contraction," E.B. Manoukian and S. Sukkhasena, _European Journal of Physics_, 23, pp. 103-110, 11 January 2002.

 > If you go to my home page you will find all the books that I have, but I do not think I will find there an answer on my questions.

Then you could benefit from reading more books and papers.

 > How to measure c is for example described in the book "Einsteins Theory of Relativity" by Max Born at page 91-93. Those pages describe the methode used by Olaf Romer, where he uses the satelites of Jupiter. The question is if that method demonstrates the statement that the laws of physics are the same for all inertial observers.

I actually enjoy Born's book, but only because of my interest in understanding his thinking in an historical context. If this book is an example of what you use to understand experimental relativity, then it is not surprising that you are so confused. Do yourself a favor; purchase and _study_ Y. Z. Zhang's "Special Relativity and its Experimental Foundations," _World Scientific_, 1997.

You have to spend some time and effort reading books and papers other than popularizations and historical artifacts.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 16 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: maandag 9 september 2002 16:08

"Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209042024410.8485-100000@inky...
 > On Wed, 4 Sep 2002, Nicolaas Vroom wrote:
 > > Where can I find the information about an experiment on length contraction ?
 > Well, if you discount things such as relativistic bond length contractions, due to s and p orbital contractions,
(It will be interesting to study this case and to "see" that the s and p orbits contract in the direction of movement of an elementary particle.)

 > then you will not find any direct measurements of length contraction on a macroscopic scale. If you want to learn about some of the difficulties involved, you can start by reading James Terrell's classic paper, "Invisibility of the Lorentz Contraction," _Physical Review_, Volume 116, Number 4, November 15, 1959, pp. 1041-1045.
This document is avalaible at University of Antwerp I will try to study it as soon as possible.

 > If you want to see a more modern treatment, with references to some of the work inbetween, see "Projection of relativistically moving objects on a two-dimensional plane, the 'train' paradox and the visibility of the Lorentz contraction," E.B. Manoukian and S. Sukkhasena, _European Journal of Physics_, 23, pp. 103-110, 11 January 2002.
This document is availble at Universtity in Hasselt (LUC) I will try to study it as soon as possible.

 > > How to measure c is for example described in the book "Einsteins Theory of Relativity" by Max Born at page 91-93. Those pages describe the methode used by Olaf Romer, where he uses the satelites of Jupiter. The question is if that method demonstrates the statement that the laws of physics are the same for all inertial observers.
 > I actually enjoy Born's book, but only because of my interest in understanding his thinking in an historical context. If this book is an example of what you use to understand experimental relativity, then it is not surprising that you are so confused. Do yourself a favor; purchase and _study_ Y. Z. Zhang's "Special Relativity and its Experimental Foundations," _World Scientific_, 1997.
This book is availble at Universtity in Hasselt (LUC)

I will study it as soon as possible.

I hope your documents also give an anwer on my question if there still is length contraction if the path of the rod is slightly bended ie follows a circle.

### 17 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: maandag 9 september 2002 17:25

On Mon, 9 Sep 2002, Nicolaas Vroom wrote:
 > "Stephen Speicher" schreef in bericht
 > > I actually enjoy Born's book, but only because of my interest in understanding his thinking in an historical context. If this book is an example of what you use to understand experimental relativity, then it is not surprising that you are so confused. Do yourself a favor; purchase and _study_ Y. Z. Zhang's "Special Relativity and its Experimental Foundations," _World Scientific_, 1997.
 > This book is availble at Universtity in Hasselt (LUC) I will study it as soon as possible. Thanks for your answers. I hope your documents also give an anwer on my question if there still is length contraction if the path of the rod is slightly bended ie follows a circle.

Did you miss the _extensive_ threads on the rotating disk which appeared here recently? Search for them on google.com and read the detailed analysis by Einstein I provided, as well as discussions by others. Another related question to ask -- and this too you must learn to answer -- is: Will a clock which is placed on the rotating circle tick at the same rate as determined by an observer at the center comparing the rate to his own clock?

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 18 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 11 september 2002 20:42

"Nicolaas Vroom" schreef in bericht news:dX1f9.109498\$8o4.15265@afrodite.telenet-ops.be...
 > "Stephen Speicher" schreef in bericht

 > > then you will not find any direct measurements of length contraction on a macroscopic scale. If you want to learn about some of the difficulties involved, you can start by reading James Terrell's classic paper, "Invisibility of the Lorentz Contraction," _Physical Review_, Volume 116, Number 4, November 15, 1959, pp. 1041-1045.
 > This document is avalaible at University of Antwerp I will try to study it as soon as possible.

I received a free copy of the article today.

My understanding of the aricle is that you can not see (visible observe) length contraction in principle and certainly not in practice.

Page 1043 discusses:
Appearance of a moving meter stick.

The book "Introducing Einstein's Relativity" by D'Inverno at page 23 discusses 2.10 "The relativity of simultaneity". In that chapter we have a train of lenght l, identical of the difference between the difference l between the two Firing Devices 1 and 2 (all in the rest frame or track frame) There is an Observer A in the middle between those two FD's The train has a velocity v (0.8*c) relative to observer A.

IMO is it not true that when the FD's fire and activate the two light sources the Observer A does not SEE the two signals simultaneous, because of length contraction of the train ? (Assuming the train moves from left to right, than FD1 (left) will be activated before FD2 (right)) (Contrary what the book suggests)

IMO this setup is in principle a method to visible demonstrate and to observe length contraction.

### 19 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: donderdag 12 september 2002 0:51

On Wed, 11 Sep 2002, Nicolaas Vroom wrote:
 > "Nicolaas Vroom" schreef in bericht
 > > "Stephen Speicher" schreef in bericht
 > > > then you will not find any direct measurements of length contraction on a macroscopic scale. If you want to learn about some of the difficulties involved, you can start by reading James Terrell's classic paper, "Invisibility of the Lorentz Contraction," _Physical Review_, Volume 116, Number 4, November 15, 1959, pp. 1041-1045.
 > > This document is avalaible at University of Antwerp I will try to study it as soon as possible.
 > I received a free copy of the article today. My understanding of the aricle is that you can not see (visible observe) length contraction in principle and certainly not in practice.

Just to be clear, the focus here is on "see (visible observe)" not measurement as performed by a standard observer.

 > Page 1043 discusses: Appearance of a moving meter stick. The book "Introducing Einstein's Relativity" by D'Inverno at page 23 discusses 2.10 "The relativity of simultaneity". In that chapter we have a train of lenght l,

d'Inverno does not specify "a train of lenght l." You have added that on your own.

 > identical of the difference between the difference l between the two Firinlength equal to the length of the carriage.
g Devices 1 and 2 (all in the rest frame or track frame)

This is so garbled I am not sure of what you mean to say. There is an observer B, at the center of one of the train carriages, and two electrical devices on the track, device 1 and device 2, separated by a
 > There is an Observer A in the middle between those two FD's

And observer A is on the bank of the track, not on the train.

 > The train has a velocity v (0.8*c) relative to observer A.

Unless you have a different edition than mine (reprinted 1999) which specifies the problem differently, you have again added something which d'Inverno does not. The velocity is only given as v, not as "(0.8*c)."

 > IMO is it not true that when the FD's fire and activate the two light sources the Observer A does not SEE the two signals simultaneous, because of length contraction of the train ?

First, d'Inverno is not referring to what observer A _sees_ (as with his eyes), but to what observer A _measures_. An "observer" in special relativity refers to a full grid array of synchronized clocks and standard rods which record the location and time of events which occur. This is different from "visual" observation in that "seeing" means the entire collection of light rays which converge upon one's eyes.

Second, d'Inverno refers to the light observed by A, not any measurements A makes as to the length of the train carriage. He stipulates that the proper length of the carriage is equal to the proper distance between the electrical devices, and therefore A being equidistant from each event will observe that they occurred simultaneously.

 > (Assuming the train moves from left to right, than FD1 (left) will be activated before FD2 (right)) (Contrary what the book suggests)

You misunderstand. In order to measure the length of an object you must mark its endpoints simultaneously. That is, in effect, what observer A has done by observing the two light sources to have switched on simultaneously. Observer A will _therefore_ measure a different length of the carriage than will be measured by observer B. However, observer B will not agree that the two events occurred simultaneously. They each have a different mixture of space and time, but they will both agree on the spacetime interval between the events.

 > IMO this setup is in principle a method to visible demonstrate and to observe length contraction.

In my opinion you are terribly confused, and asking for sophisticated references, as the paper's which I gave, is way beyond your ken. I would suggest you back up and start from the beginning. Although d'Inverno's book has some nice qualities, you would benefit a great deal more by a better systematic approach such as that presented by Taylor and Wheeler in "Spacetime Physics."

It might also help if you made an attempt to change your overall attitude, from trying to show what is wrong with relativity, to trying to understand what it actually is.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 20 Re: SR is succesfully debunked, spread the word.

Van: "Jan Bielawski" Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: donderdag 12 september 2002 3:19

"Nicolaas Vroom" wrote in message news:...
 > "Nicolaas Vroom" schreef in bericht
 > > "Stephen Speicher" schreef in bericht
 > > > then you will not find any direct measurements of length contraction on a macroscopic scale. If you want to learn about some of the difficulties involved, you can start by reading James Terrell's classic paper, "Invisibility of the Lorentz Contraction," _Physical Review_, Volume 116, Number 4, November 15, 1959, pp. 1041-1045.
 > > This document is avalaible at University of Antwerp I will try to study it as soon as possible.
 > I received a free copy of the article today. My understanding of the aricle is that you can not see (visible observe) length contraction in principle

That can't be right. I haven't seen this paper (yet) but in principle length contraction is visible (compunded with distortions due to signal delay). It is only invisible if the object is far enough so that it does not subtend a large angle of view plus the observation is monocular (no stereo vision). Enough discernible surface detail would also betray a net distortion, I think.

Jan Bielawski

### 21 Re: SR is succesfully debunked, spread the word.

Van: "Russell Blackadar" Onderwerp: Re: SR is succesfully debunked, spread the word. Datum: donderdag 12 september 2002 22:50

(Removing sci.physics. Do not cross-post!)

Jan Bielawski wrote:
 > "Nicolaas Vroom" wrote in message news:..

[snip]

 > > My understanding of the aricle is that you can not see (visible observe) length contraction in principle
 > That can't be right. I haven't seen this paper (yet) but in principle length contraction is visible (compunded with distortions due to signal delay). It is only invisible if the object is far enough so that it does not subtend a large angle of view plus the observation is monocular (no stereo vision).

Terrell agrees with you, Jan. He explicitly says that the effect he's talking about only applies in cases where perspective can be neglected. A lot of folks around here seem to miss that disclaimer in his paper.

 > Enough discernible surface detail would also betray a net distortion, I think.

Well, I'm not quite sure what you mean here, but indeed even at a great distance there can be unmistakable clues that the rotation is an illusion. For example, imagine looking at the pole-and-barn scenario from the side, in the barn's frame. If you were a long distance away, the pole might look exactly as if it had its original length but is rotated so that its leading end is away from you. And yet, you can watch it pass through a tiny door in the barn that is no larger than the pole's diameter, something it could never do unless it were truly oriented parallel to the direction of its motion.

### 22 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 13 september 2002 2:50

 > (Removing sci.physics. Do not cross-post!) Jan Bielawski wrote:
 > > "Nicolaas Vroom" wrote in message news:..
 > [snip]
 > > > My understanding of the aricle is that you can not see (visible observe) length contraction in principle
 > > That can't be right. I haven't seen this paper (yet) but in principle length contraction is visible (compunded with distortions due to signal delay). It is only invisible if the object is far enough so that it does not subtend a large angle of view plus the observation is monocular (no stereo vision).
 > Terrell agrees with you, Jan.

In his paper, Terrell states:

"Quite generally, objects will appear the same shape, visually, to all observers, no matter what the relative motion of object and unaccelerated observer may be. ... In this way the apparent shape of an object is invariant to the Lorentz transformation, although the 'actual' shape, as given by careful measurement, will vary due to the Lorentz contraction"

The only qualifications which he makes are those for simplicity of analysis, not for generality of conclusion. What exactly is it in Terrell's paper which leads you to conclude that he agrees with Jan that "length contraction is visible?"

 > He explicitly says that the effect he's talking about only applies in cases where perspective can be neglected. A lot of folks around here seem to miss that disclaimer in his paper.

What he "explicitly says" is:

"Thus the Lorentz contraction is effectively invisble. Only when stereoscopic vision or photography is used, combining observations from two different locations, can any distortion of the object due to motion be seen, and even this is not the expected contraction, as will be discussed in a later section."

The "combining observations from two different locations" is hardly what is meant when Lorentz contraction is discussed in special relativity.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 23 Re: SR is succesfully debunked, spread the word.

Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 13 september 2002 3:55

Stephen Speicher wrote:
 > On Thu, 12 Sep 2002, Russell Blackadar wrote:
 > > (Removing sci.physics. Do not cross-post!) Jan Bielawski wrote:
 > > > "Nicolaas Vroom" wrote in message news:..
 > > [snip]
 > > > > My understanding of the aricle is that you can not see (visible observe) length contraction in principle
 > > > That can't be right. I haven't seen this paper (yet) but in principle length contraction is visible (compunded with distortions due to signal delay). It is only invisible if the object is far enough so that it does not subtend a large angle of view plus the observation is monocular (no stereo vision).
 > > Terrell agrees with you, Jan.
 > In his paper, Terrell states: "Quite generally, objects will appear the same shape, visually, to all observers, no matter what the relative motion of object and unaccelerated observer may be. ... In this way the apparent shape of an object is invariant to the Lorentz transformation, although the 'actual' shape, as given by careful measurement, will vary due to the Lorentz contraction" The only qualifications which he makes are those for simplicity of analysis, not for generality of conclusion. What exactly is it in Terrell's paper which leads you to conclude that he agrees with Jan that "length contraction is visible?"

Hmm, I don't seem any longer to have access to the website where I read the paper in PDF version, early this year. But my recollection is that there is a whole section of the paper -- near the end of it -- devoted to a discussion of the effects where perspective is important. My earlier post on this topic is

 >
 > > He explicitly says that the effect he's talking about only applies in cases where perspective can be neglected. A lot of folks around here seem to miss that disclaimer in his paper.
 > What he "explicitly says" is: "Thus the Lorentz contraction is effectively invisble. Only when stereoscopic vision or photography is used, combining observations from two different locations, can any distortion of the object due to motion be seen, and even this is not the expected contraction, as will be discussed in a later section."

That later section must be the one I'm remembering. As I recall (sorry I can't verify it) the point he makes in that section is that his analysis in the paper is only good if the subtended solid angle is small. In other words (IIRC) he was actually more restrictive, in that section, than in his brief comment that you quoted above.

 > The "combining observations from two different locations" is hardly what is meant when Lorentz contraction is discussed in special relativity.

Well, that's a debatable point IMO since with Terrell rotation (a "seen" effect) we are already pretty much out of that realm from the get-go.

In any case, whether or not Terrell said so, Jan is right. Just take a look at the (nonstereographic, but nearby) view of a relativistic tram car on http://www.anu.edu.au/Physics/Searle/ and you can immediately see the perspective is all wrong for a rotation; it is obviously a shortening and shear. Of course we can say that because we know what the tram should look like in its own frame, and that might not be so clear for (say) a celestial body -- and in particular the difference would indeed be invisible for a sphere. Perhaps that's what Jan had in mind when he mentioned surface features.

### 24 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 13 september 2002 5:10

 > Stephen Speicher wrote:
 > > On Thu, 12 Sep 2002, Russell Blackadar wrote:
 > > > (Removing sci.physics. Do not cross-post!) Jan Bielawski wrote:
 > > > > "Nicolaas Vroom" wrote in message news:..
 > > > [snip]
 > > > > > My understanding of the aricle is that you can not see (visible observe) length contraction in principle
 > > > > That can't be right. I haven't seen this paper (yet) but in principle length contraction is visible (compunded with distortions due to signal delay). It is only invisible if the object is far enough so that it does not subtend a large angle of view plus the observation is monocular (no stereo vision).
 > > > Terrell agrees with you, Jan.
 > > In his paper, Terrell states: "Quite generally, objects will appear the same shape, visually, to all observers, no matter what the relative motion of object and unaccelerated observer may be. ... In this way the apparent shape of an object is invariant to the Lorentz transformation, although the 'actual' shape, as given by careful measurement, will vary due to the Lorentz contraction" The only qualifications which he makes are those for simplicity of analysis, not for generality of conclusion. What exactly is it in Terrell's paper which leads you to conclude that he agrees with Jan that "length contraction is visible?"
 > Hmm, I don't seem any longer to have access to the website where I read the paper in PDF version, early this year. But my recollection is that there is a whole section of the paper -- near the end of it -- devoted to a discussion of the effects where perspective is important. My earlier post on this topic is
 > >
 > > > He explicitly says that the effect he's talking about only applies in cases where perspective can be neglected. A lot of folks around here seem to miss that disclaimer in his paper.
 > > What he "explicitly says" is: "Thus the Lorentz contraction is effectively invisble. Only when stereoscopic vision or photography is used, combining observations from two different locations, can any distortion of the object due to motion be seen, and even this is not the expected contraction, as will be discussed in a later section."
 > That later section must be the one I'm remembering. As I recall (sorry I can't verify it) the point he makes in that section is that his analysis in the paper is only good if the subtended solid angle is small. In other words (IIRC) he was actually more restrictive, in that section, than in his brief comment that you quoted above.

Terrell assumes that "the object subtends an angle sufficiently small" so as "to simplify matters," because "whether to use photographic film which lies in a plane or is curved so that allpoints are at the same distance from the lens (or pinhole), and whether to use a lens corrected to eliminate oprical distortions," that these such matters could be "troublesome."

 > > The "combining observations from two different locations" is hardly what is meant when Lorentz contraction is discussed in special relativity.
 > Well, that's a debatable point IMO since with Terrell rotation (a "seen" effect) we are already pretty much out of that realm from the get-go. In any case, whether or not Terrell said so, Jan is right. Just take a look at the (nonstereographic, but nearby) view of a relativistic tram car on http://www.anu.edu.au/Physics/Searle/ and you can immediately see the perspective is all wrong for a rotation; it is obviously a shortening and shear. Of course we can say that because we know what the tram should look like in its own frame, and that might not be so clear for (say) a celestial body -- and in particular the difference would indeed be invisible for a sphere. Perhaps that's what Jan had in mind when he mentioned surface features.

The link shows what we would see if we were in a world where we were able to see length contraction. This is a visualization site, not a theoretical presentation. According to Terrell -- and to many others who have studied this later -- the shear is not length contraction, but rather an effect of stereoscopic vision. There is a lot of literature on this in the field. For an example of a presentation which _does_ think that length contraction _can_ be seen, see "Projection of relativistically moving objects on a two-dimensional plane, the 'train' paradox and the visibility of the Lorentz contraction," E. B. Manoukian and S. Sukkhasena, _European Journal of Physics_, 23 (2): pp. 103-110, March 2002. But, even there, going against the more standard interpretation, the authors argue for visibility of length contraction which is only visible in the small neighborhood surrounding a critical point. Certainly not general visibility of length contraction.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 25 Re: SR is succesfully debunked, spread the word.

Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 13 september 2002 6:48

Stephen Speicher wrote:
 > On Thu, 12 Sep 2002, Russell Blackadar wrote:
 > > Stephen Speicher wrote:

[on whether Terrell rotation requires objects to be distant]

 > Terrell assumes that "the object subtends an angle sufficiently small" so as "to simplify matters," because "whether to use photographic film which lies in a plane or is curved so that allpoints are at the same distance from the lens (or pinhole), and whether to use a lens corrected to eliminate oprical distortions," that these such matters could be "troublesome."

Ok, thanks for checking. I can't argue over what Terrell said, since you have the source and I don't. I probably must concede that I read more into the word "troublesome" than was merited.

 >
 > > > The "combining observations from two different locations" is hardly what is meant when Lorentz contraction is discussed in special relativity.
 > > Well, that's a debatable point IMO since with Terrell rotation (a "seen" effect) we are already pretty much out of that realm from the get-go. In any case, whether or not Terrell said so, Jan is right. Just take a look at the (nonstereographic, but nearby) view of a relativistic tram car on http://www.anu.edu.au/Physics/Searle/ and you can immediately see the perspective is all wrong for a rotation; it is obviously a shortening and shear. Of course we can say that because we know what the tram should look like in its own frame, and that might not be so clear for (say) a celestial body -- and in particular the difference would indeed be invisible for a sphere. Perhaps that's what Jan had in mind when he mentioned surface features.
 > The link shows what we would see if we were in a world where we were able to see length contraction. This is a visualization site, not a theoretical presentation.

Obviously. Still, the picture looks correct to me. It's pretty easy to trace the rays manually for a few points and verify that it's not grossly wrong.

 > According to Terrell -- and to many others who have studied this later -- the shear is not length contraction, but rather an effect of stereoscopic vision.

Hmm? I never said it was length contraction. I said it was *superimposed* on the length contraction. The sum of the two effects is what gives the appearance of a rotation.

Regarding whether it has anything to do with stereo vision, I believe there may be a misunderstanding between us, and perhaps the authors you are referring to here, over what would constitute *observation* of length contraction (vs. rotation). I will say that if you do not know a priori and in considerable detail what shape the object has in its rest frame, then yes you do need some method of rangefinding (stereo vision will do) to tell the difference between a contraction+shear vs. a rotation. But, if you *do* know the object's actual shape, then perspective in a single view is enough, assuming the object is close enough.

 > There is a lot of literature on this in the field. For an example of a presentation which _does_ think that length contraction _can_ be seen, see "Projection of relativistically moving objects on a two-dimensional plane, the 'train' paradox and the visibility of the Lorentz contraction," E. B. Manoukian and S. Sukkhasena, _European Journal of Physics_, 23 (2): pp. 103-110, March 2002.

I do not wish to put myself up against all this literature, since my arguments are quite naive, but really....

 > But, even there, going against the more standard interpretation, the authors argue for visibility of length contraction which is only visible in the small neighborhood surrounding a critical point. Certainly not general visibility of length contraction.

I never said *general*.

Look, imagine you are watching 4x8 sheet of plywood fly by, oriented normal to your line of sight, with its center on that line, and moving in the direction of its long axis at gamma=2. Close one of your eyes if you wish. ;-)

The four corners of the plywood are equidistant from your eye at this instant; call that distance L. At time L/c, you will see an image of those four points arrayed in the shape of a square, thanks to contraction. Now, if the plywood were its proper length but just rotated 60 degrees, it would also look like a square *if L is large*. OTOH if L is small, the image should be a trapezoid due to geometric perspective. This is an observable difference, if L is small.

(Note, my plywood is like the near side of the tram, at the SR visualization site. The fact that this side looks like a rectangle and not a trapezoid proves that it is not really rotated. Note btw that the visible end of the car *does* show perspective, which is why the distortion is so obvious to the eye.)

Yes you *do* have to know beforehand that the plywood is not itself a trapezoid in its rest frame, in order to reach such a conclusion. As I mentioned before, this may be the explanation of some of the differences between what I have said, and what is said in the literature.

### 26 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 13 september 2002 22:23

"Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209111454290.14377-100000@blinky...
 > On Wed, 11 Sep 2002, Nicolaas Vroom wrote:
 > > "Nicolaas Vroom" schreef in bericht My understanding of the aricle is that you can not see (visible observe) length contraction in principle and certainly not in practice.
 > Just to be clear, the focus here is on "see (visible observe)" not measurement as performed by a standard observer.
 > > Page 1043 discusses: Appearance of a moving meter stick. The book "Introducing Einstein's Relativity" by D'Inverno at page 23 discusses 2.10 "The relativity of simultaneity". In that chapter we have a train of lenght l,
 > d'Inverno does not specify "a train of lenght l." You have added that on your own.
The length of the train should have been l0 ie the proper length in the restframe measured with v=0

 > > identical of the difference between the difference l between the two Firing Devices 1 and 2 (all in the rest frame or track frame)
 > This is so garbled I am not sure of what you mean to say. There is an observer B, at the center of one of the train carriages, and two electrical devices on the track, device 1 and device 2, separated by a length equal to the length of the carriage.

Again I should have written: the difference l0 between the two FD's 1 and 2. This means when the train is at rest the two lightsources should be on.

 > > There is an Observer A in the middle between those two FD's
 > And observer A is on the bank of the track, not on the train.
 > > The train has a velocity v (0.8*c) relative to observer A.
 > Unless you have a different edition than mine (reprinted 1999) which specifies the problem differently, you have again added something which d'Inverno does not. The velocity is only given as v, not as "(0.8*c)."

Correct.
I have added 0.8*c to make it compatible with the document by James Terrell

 > > IMO is it not true that when the FD's fire and activate the two light sources the Observer A does not SEE the two signals simultaneous, because of length contraction of the train ?
 > First, d'Inverno is not referring to what observer A _sees_ (as with his eyes), but to what observer A _measures_. An "observer" in special relativity refers to a full grid array of synchronized clocks and standard rods which record the location and time of events which occur. This is different from "visual" observation in that "seeing" means the entire collection of light rays which converge upon one's eyes.

The difference between sees and measures is rather "tricky". d'Inverno writes:
"Since the speed of light is a constant, B will see the light from source 2 before seeing the light from source 1 etc." That means B needs two detectors and two clocks to measure when the light source signals reach him.

d'Inverno also writes:
"From the configuration it is clear that A will judge that the two events when the light sources first switch on, occur simultaneously" IMO (I agree) d'Inverno does not write what A actual sees. IMO he also does not write what A observes nor what A measures. However my interpretation of the text is that if "you" perform this experiment A actual sees the light sources simultaneous. (measures it arrive time)

 > Second, d'Inverno refers to the light observed by A, not any measurements A makes as to the length of the train carriage. He stipulates that the proper length of the carriage is equal to the proper distance between the electrical devices, and therefore A being equidistant from each event will observe that they occurred simultaneously.

IMO the drawing the drawing does not reflect the situation when v>0 IMO as I already stated before when v>0 there is length contraction implying that the firing devices do not fire simulataneous and that A does not see the lights simultaneous.

IMO the real question to be answered is: Is length contraction involved in the train experiment ie fig 2.13 (Part of 2.10 The relativity of simultaneity)

 > > (Assuming the train moves from left to right, than FD1 (left) will be activated before FD2 (right)) (Contrary what the book suggests)
 > You misunderstand. In order to measure the length of an object you must mark its endpoints simultaneously. That is, in effect, what observer A has done by observing the two light sources to have switched on simultaneously. Observer A will _therefore_ measure a different length of the carriage than will be measured by observer B. However, observer B will not agree that the two events occurred simultaneously. They each have a different mixture of space and time, but they will both agree on the spacetime interval between the events.

IMO (I agree) if v>0 and if A observes the two light simultaneous than B (moving observer) will not see the two light simultaneous.

 > > IMO this setup is in principle a method to visible demonstrate and to observe length contraction.
 > In my opinion you are terribly confused, and asking for sophisticated references, as the paper's which I gave, is way beyond your ken.
I have studied the paper by James Terrell. The conclusion of that paper is that you can not "make length contraction visible" IMO this is not true if you perform the experiment as described by d'Inverno.

I do not fully understand the final sentence of the document: "None of the statements here should be construed as casting any doubt on either the observability or the reality of the Lorentz contraction as all the results given are derived from the special theory of relativity"

 > I would suggest you back up and start from the beginning. Although d'Inverno's book has some nice qualities, you would benefit a great deal more by a better systematic approach such as that presented by Taylor and Wheeler in "Spacetime Physics."

I have the book "A Journey into Gravity and Spacetime" by Wheeler

 > It might also help if you made an attempt to change your overall attitude, from trying to show what is wrong with relativity, to trying to understand what it actually is.

### 27 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zaterdag 14 september 2002 6:10

[Big snip of pointless repetition and further confusion.]

 > IMO (I agree) d'Inverno does not write... IMO he also does not write... However my interpretation... IMO the drawing the drawing does not... IMO as I already stated before... IMO the real question to be answered... IMO (I agree) if v>0 and if A observes... IMO this is not true if you perform...
 > > It might also help if you made an attempt to change your overall attitude, from trying to show what is wrong with relativity, to trying to understand what it actually is.
 >

IMO, you should have listened to what I wrote above instead of continuing to write lines of "IMO." Unless you wipe your mind clean of all the misconceptions about relativity which you have accumulated in the past five years, and unless you study the subject from a proper perspective (such as is presented in the book I recommended), you are doomed to repeat your same mistakes over and over again. But, without me, at least until you show some indication that you are capable of and willing to learn.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 28 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zaterdag 14 september 2002 16:44

"Stephen Speicher" schreef in bericht
 > IMO, you should have listened to what I wrote above instead of continuing to write lines of "IMO." Unless you wipe your mind clean of all the misconceptions about relativity which you have accumulated in the past five years, and unless you study the subject from a proper perspective (such as is presented in the book I recommended),
The book by Wheeler as suggested is available at the University of Antwerp. In due time I will study it.

 > you are doomed to repeat your same mistakes over and over again. But, without me, at least until you show some indication that you are capable of and willing to learn. -- Stephen sjs@compbio.caltech.edu

The sad thing about this thread that still I do not know, when you perform the train experiment, as described by d'Inverno if you have to take length contraction into account.

### 29 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zaterdag 14 september 2002 21:51

On Sat, 14 Sep 2002, Nicolaas Vroom wrote:
 > "Stephen Speicher" schreef in bericht
 > > IMO, you should have listened to what I wrote above instead of continuing to write lines of "IMO." Unless you wipe your mind clean of all the misconceptions about relativity which you have accumulated in the past five years, and unless you study the subject from a proper perspective (such as is presented in the book I recommended),
 > The book by Wheeler as suggested is available at the University of Antwerp. In due time I will study it.

The sooner the better. However, to reiterate, your mental set must be such that you are able and willing to take a fresh look at the subject. If you bring your years of accumulated baggage to the learning experience, I strongly suspect you will wind up right back where you started.

 > > you are doomed to repeat your same mistakes over and over again. But, without me, at least until you show some indication that you are capable of and willing to learn.
 > The sad thing about this thread that still I do not know, when you perform the train experiment, as described by d'Inverno if you have to take length contraction into account.

No. The really sad thing is that after five years you continue to remain focused on what you suppose is wrong with relativity, rather than actually learning what the theory advocates. I suspect that what you "do not know" has more to do with you not wanting to know than just lack of knowledge.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 30 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zondag 15 september 2002 12:43

"Jan Bielawski" schreef in bericht news:db455fa2.0209111719.4efae99d@posting.google.com...
 > "Nicolaas Vroom" wrote in message
news:...

 > > My understanding of the aricle is that you can not see (visible observe) length contraction in principle
 > That can't be right. I haven't seen this paper (yet) but in principle length contraction is visible (compunded with distortions due to signal delay). It is only invisible if the object is far enough so that it does not subtend a large angle of view plus the observation is monocular (no stereo vision). Enough discernible surface detail would also betray a net distortion, I think.

The article starts with a distinction between observing and seeing. Observing involves what is observed when the photons leave the 3D object simultaneous and reach the observer at different times. Seeing involves what you see when the photons reach the observer simultaneous. Those photons left the 3D object at different times.

At page 1044 in paragraph "Stereoscopic Vision" is written: "This produces curious visual distortions ...., constituting shear (meaning cuts ?) and contraction or elongation. See the actual article for more details.

In this respect it is interesting to read and study the simulation that is part of my home page https://www.nicvroom.be/ In the paragraphs length contraction part 1 and part 2 this same problem is discussed (I wrote the simulation 10 years ago) In the paragraph length contraction part 2 specific is discussed what you "see" when you move a stick under a slight angle away or towards an observer.
In the first case the stick is "seen shorter as stick is without taken length contraction into account" and in the second case the stick is "seen longer as the stick is etc"
That means when length contraction is taken into account when the stick moves away there are two effects which amplify each other and when the stick moves towards you the two effects tend to elimate each other.
This ofcourse makes observation of only length contraction very difficult.

The only way IMO if you want to observe length contaction is when you move a stick in the x direction and when there is an observer at the position x1,y1
The moment when the centre of the stick is than approx at pos (x1,0) is than the most interesting.
What you need is something as the train experiment described by d'Inverno. You need two contacts a distance l0 appart. l0 being also the length of the train (stick) with v=0.
When you this experiment with v>0 and when the light signals reach the observer simultaneous there is no length contraction involved.
When the light signals do not reach the observer simultaneous than you know that the reason is length contaction.

However Stephen Speicher tells me there is NO length contraction involved in this experiment, implying (my conclusion) that independent of any speed of the train the observer always sees the two light signals simultaneous.
(Assuming one specific length l0 of the train)

I do not understand that within the frame of SR.

### 31 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zondag 15 september 2002 15:34

"Russell Blackadar" schreef in bericht news:3D814590.2C379162@mdli.com...

 > In any case, whether or not Terrell said so, Jan is right. Just take a look at the (nonstereographic, but nearby) view of a relativistic tram car on http://www.anu.edu.au/Physics/Searle/ and you can immediately see the perspective is all wrong for a rotation; it is obviously a shortening and shear.

Can someone explain me what the word shear means. Read in the Webster it means to cut.

I'am studying this url. It is all very interesting.

### 32 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: zondag 15 september 2002 17:26

"Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209141245190.29743-100000@blinky...
 > On Sat, 14 Sep 2002, Nicolaas Vroom wrote:
 > > The sad thing about this thread that still I do not know, when you perform the train experiment, as described by d'Inverno if you have to take length contraction into account.
 > No.

That is a straight forward reply.
Your reply implies, assuming at a certain speed (including v=0) that Observer A sees the two light simultaneous and assuming that the same physical train is used, that than Observer A will see the two lights simultaneous at any speed of this experiment.
The explanation is that no length contraction is involved. I do not understand this within the framework of SR.

Hopefully your suggested litterature will solve this.

Nick

### 33 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: maandag 16 september 2002 2:57

On Sun, 15 Sep 2002, Nicolaas Vroom wrote:
 > However Stephen Speicher tells me there is NO length contraction involved in this experiment...

I said nothing of the kind, and I would appreciate you not attributing to me your own personal misunderstandings. If you want to appeal to something I said then, instead of presenting your confused interpretation, please quote me exactly, and in full context.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons.
-----------------------------------------------------------

### 34 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: maandag 16 september 2002 3:10

On Sun, 15 Sep 2002, Nicolaas Vroom wrote:
 > "Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209141245190.29743-100000@blinky...
 > > On Sat, 14 Sep 2002, Nicolaas Vroom wrote:
 > > > The sad thing about this thread that still I do not know, when you perform the train experiment, as described by d'Inverno if you have to take length contraction into account.
 > > No.
 > That is a straight forward reply.

If so, then why did you snip the full context of my reply? I reinstate it below.

"No. The really sad thing is that after five years you continue to remain focused on what you suppose is wrong with relativity, rather than actually learning what the theory advocates. I suspect that what you "do not know" has more to do with you not wanting to know than just lack of knowledge."

 > Your reply implies, assuming at a certain speed (including v=0) that Observer A sees the two light simultaneous and assuming that the same physical train is used, that than Observer A will see the two lights simultaneous at any speed of this experiment.

No. My reply implies -- or, rather, states explicitly -- that you are ignorant of relativity and that seems to be your chosen state. Please stop taking a small piece of my words, as you have done here, and make it appear that they imply something else than my words really do.

 > The explanation is that no length contraction is involved. I do not understand this within the framework of SR.

You do not seem to understand plain English, much less relativity.

 > Hopefully your suggested litterature will solve this.

The suggested literature explains relativity in a clear, rational manner. Whether or not you choose to understand it is up to you.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons. -----------------------------------------------------------

### 35 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: donderdag 19 september 2002 11:06

"Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209111454290.14377-100000@blinky...
 > On Wed, 11 Sep 2002, Nicolaas Vroom wrote:
 > > Page 1043 discusses: Appearance of a moving meter stick. The book "Introducing Einstein's Relativity" by D'Inverno at page 23 discusses 2.10 "The relativity of simultaneity". In that chapter we have a train of lenght l,
 > d'Inverno does not specify "a train of lenght l." You have added that on your own.
SNIP

 > > IMO is it not true that when the FD's fire and activate the two light sources the Observer A does not SEE the two signals simultaneous, because of length contraction of the train ?
 > First, d'Inverno is not referring to what observer A _sees_ (as with his eyes), but to what observer A _measures_. An "observer" in special relativity refers to a full grid array of synchronized clocks and standard rods which record the location and time of events which occur. This is different from "visual" observation in that "seeing" means the entire collection of light rays which converge upon one's eyes. Second, d'Inverno refers to the light observed by A, not any measurements A makes as to the length of the train carriage. He stipulates that the proper length of the carriage is equal to the proper distance between the electrical devices, and therefore A being equidistant from each event will observe that they occurred simultaneously.
SNIP

 > > IMO this setup is in principle a method to visible demonstrate and to observe length contraction.
 > In my opinion you are terribly confused, and asking for sophisticated references, as the paper's which I gave, is way beyond your ken. I would suggest you back up and start from the beginning. Although d'Inverno's book has some nice qualities, you would benefit a great deal more by a better systematic approach such as that presented by Taylor and Wheeler in "Spacetime Physics."

Yesterday I studied (part of) this book by T&W.

At page 62-63 "Relativity of Simultaneity" and the train experiment is discussed.
The two experiments are slightly different. IMO the experiment by T&W works and the experiment by d'Inverno does not work assuming my understanding is correct.

In the experiment by T&W there are two lightning flashes which hit the ends of the train (one lightning the front end one lightning the back end) and which leave two marks on the track.
Observer A near track, which stands in the middle of those two marks sees those two flashes simultaneous.

In actual fact this is a very difficult experiment to perform but in principle it is possible.

For me the question is: When you stop the train and you compare the two marks with the length of the train. Do they match ?

The experiment by d'Inverno starts from two electrical devices. If those two electrical devices are the length of the carriage appart as measured in the rest frame (track frame) than IMO the experiment will not work when the train has a speed v. In that case Observer A will not see the two lights simultaneous.

IMO for each specific speed of the train you have to adjust the position (and the distance between) of both electrical devices in order for Observer A to see the two signals simultaneous.

If you do that and Observer A sees the two light signals (or lightning flashes simultaneous) than ofcourse Observer B (on the moving train) will not see the two lights simultaneous.

Paragraph 3-17 is called: "contraction or rotation ?"

There is written:
Hence, when one sees the cube to be overhead one will see the Lorentz contraction of the bottom edge.

Near the figure part of excercise 3-17 is written: "How the visual observer can interpret the projection of the second figure"

The second figure shows (part of) the angle of apparant rotation Theta.

### 36 Re: SR is succesfully debunked, spread the word.

Van: "Stephen Speicher"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: donderdag 19 september 2002 23:47

On Thu, 19 Sep 2002, Nicolaas Vroom wrote:
 > Yesterday I studied (part of) this book by T&W. At page 62-63 "Relativity of Simultaneity" and the train experiment...

Look, Nicolaas, I tried to get across that you need to change your entire attitude, and instead of trying to explain what is wrong with relativity, you need to wipe your mind clean and actually learn the subject from the beginning. Instead of taking my advice, you went straight to the "train" problem about which you are obsessed, instead of first trying to understand the basis for the theory.

I have no further interest in discussing this with you, until and unless you first educate yourself as to what relativity is, on a basic level. If you want to discuss your own misconceptions and relate them to the "train" problem, I'm sure you can find some who will enjoy doing this with you. You might try josX, for starters.

--
Stephen
sjs@compbio.caltech.edu

Printed using 100% recycled electrons. -----------------------------------------------------------

### 37 Re: SR is succesfully debunked, spread the word.

Van: "Spaceman"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 20 september 2002 17:21

 > Look, Nicolaas, I tried to get across that you need to change your entire attitude, and instead of trying to explain what is wrong with relativity, you need to wipe your mind clean and actually learn the subject from the beginning.

Translation,
for you to think "Sherlock Holmes was real" you need to start from the beginnings and read all his books.
:)

In other words.
He wants you to "try and get brainwashed again"
:)

James M Driscoll Jr
Spaceman
http://www.realspaceman.com

### 38 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 25 september 2002 14:18

"Stephen Speicher" schreef in bericht news:Pine.GSO.4.42.0209191438470.403-100000@sue...
 > On Thu, 19 Sep 2002, Nicolaas Vroom wrote:
 > > Yesterday I studied (part of) this book by T&W. At page 62-63 "Relativity of Simultaneity" and the train experiment...
 > Look, Nicolaas, I tried to get across that you need to change your entire attitude, and instead of trying to explain what is wrong with relativity, you need to wipe your mind clean etc.

I tried to compare to identical subjects in two different books and I found some discrepancies. I did what you can call a literature study.

The sad thing is that I still do not know if those discrepancies are real or if they are caused by lack of understanding from my part.

As part of the book by T&W they discussed how to measure Length Contraction. In order to do that you need a 3D grid (latticework) with clocks synchronised in the frame of the Observer (My words, the book is in the library). They showed a 3D view of such a latticework. The thought came up in my mind:

How do you do that in practice ?
Has it ever been done ?

For any one who wants to see a simulation of Terrell Rotation please go to: https://www.nicvroom.be/terrell.htm
or go to https://www.nicvroom.be/ and select and select question 7: Changing Length

Nick

### 39 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: dinsdag 8 oktober 2002 23:10

"Nicolaas Vroom" schreef in bericht news:dQhk9.131493\$8o4.19573@afrodite.telenet-ops.be...
 > I tried to compare to identical subjects in two different books and I found some discrepancies. I did what you can call a literature study. The sad thing is that I still do not know if those discrepancies are real or if they are caused by lack of understanding from my part.

In order to solve (?) this issue please fill in this questionary: https://www.nicvroom.be/trainfb_form.htm You can also go to this page via 7 Changing Length

Your effort will be very much appreciated.

### 40 Re: SR is succesfully debunked, spread the word.

Van: "rryker"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 9 oktober 2002 0:33

 > "Nicolaas Vroom" schreef in bericht news:dQhk9.131493\$8o4.19573@afrodite.telenet-ops.be...
 > > I tried to compare to identical subjects in two different books and I found some discrepancies. I did what you can call a literature study. The sad thing is that I still do not know if those discrepancies are real or if they are caused by lack of understanding from my part.
 > In order to solve (?) this issue please fill in this questionary: https://www.nicvroom.be/trainfb_form.htm You can also go to this page via 7 Changing Length Your effort will be very much appreciated.

Rod: Length contraction does not occur, period. --
Rod Ryker...
It is reasoning and faith that bind truth. http://herr_ryker.tripod.com/

### 41 Re: SR is succesfully debunked, spread the word.

Van: "Nicolaas Vroom"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: woensdag 9 oktober 2002 21:07

"rryker" schreef in bericht news:3DA35D52.9A3712B6@fuse.net...
 > Nicolaas Vroom wrote:
 > > In order to solve (?) this issue please fill in this questionary: https://www.nicvroom.be/trainfb_form.htm You can also go to this page via 7 Changing Length Your effort will be very much appreciated.
 > Rod: Length contraction does not occur, period.

Thanks with your reply. I understand your point of view based on your posting in sci.physics.relativity: "Length contraction reality". (In short you do not agree with SR) But that does not mean I agree with you.

I hope people fill in the questionary and maybe if they are lucky......

 > -- Rod Ryker... It is reasoning and faith that bind truth. http://herr_ryker.tripod.com/

This url does not work.

### 42 Re: SR is succesfully debunked, spread the word.

Van: "rryker"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: donderdag 10 oktober 2002 3:16

 > "rryker" schreef in bericht news:3DA35D52.9A3712B6@fuse.net...
 > > Nicolaas Vroom wrote:
 > > > In order to solve (?) this issue please fill in this questionary: https://www.nicvroom.be/trainfb_form.htm You can also go to this page via 7 Changing Length Your effort will be very much appreciated.
 > > Rod: Length contraction does not occur, period.
 > Thanks with your reply. I understand your point of view based on your posting in sci.physics.relativity: "Length contraction reality". (In short you do not agree with SR) But that does not mean I agree with you.

Rod: Hi Nick, it does not matter what I think, my examples on my web site show some of what SR claims is not accurate.

 > I hope people fill in the questionary and maybe if they are lucky......
 > > -- Rod Ryker... It is reasoning and faith that bind truth. http://herr_ryker.tripod.com/
 > This url does not work.

Rod: My URL works fine. There is an underscore between herr and ryker. Or try:
http://herr_ryker.tripod.com/herrryker --
Rod Ryker... It is reasoning and faith that bind truth. http://herr_ryker.tripod.com/

Created: 16 September 2002