| 1 "Robert J. Kolker" |
Re: SR is succesfully debunked, spread the word. | woensdag 28 augustus 2002 20:54 |
| 2 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | zondag 1 september 2002 11:10 |
| 3 "Robert J. Kolker" |
Re: SR is succesfully debunked, spread the word. | zondag 1 september 2002 13:15 |
| 4 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | zondag 1 september 2002 15:55 |
| 5 "Robert J. Kolker" |
Re: SR is succesfully debunked, spread the word. | zondag 1 september 2002 15:59 |
| 6 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | maandag 2 september 2002 23:05 |
| 7 "Robert J. Kolker" |
Re: SR is succesfully debunked, spread the word. | dinsdag 3 september 2002 0:08 |
| 8 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | dinsdag 3 september 2002 7:59 |
| 9 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | dinsdag 3 september 2002 8:18 |
| 10 "Jan C. Bernauer" |
Re: SR is succesfully debunked, spread the word. | dinsdag 3 september 2002 9:50 |
| 11 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | dinsdag 3 september 2002 22:35 |
| 12 "MasterCougar" |
Re: SR is succesfully debunked, spread the word. | woensdag 4 september 2002 3:45 |
| 13 "Randy Poe" |
Re: SR is succesfully debunked, spread the word. | woensdag 4 september 2002 18:59 |
| 14 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | woensdag 4 september 2002 21:21 |
| 15 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | donderdag 5 september 2002 6:07 |
| 16 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | maandag 9 september 2002 16:08 |
| 17 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | maandag 9 september 2002 17:25 |
| 18 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | woensdag 11 september 2002 20:42 |
| 19 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | donderdag 12 september 2002 0:51 |
| 20 "Jan Bielawski" |
Re: SR is succesfully debunked, spread the word. | donderdag 12 september 2002 3:19 |
| 21 "Russell Blackadar" |
Re: SR is succesfully debunked, spread the word. | donderdag 12 september 2002 22:50 |
| 22 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | vrijdag 13 september 2002 2:50 |
| 23 "Russell Blackadar" |
Re: SR is succesfully debunked, spread the word. | vrijdag 13 september 2002 3:55 |
| 24 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | vrijdag 13 september 2002 5:10 |
| 25 "Russell Blackadar" |
Re: SR is succesfully debunked, spread the word. | vrijdag 13 september 2002 6:48 |
| 26 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | vrijdag 13 september 2002 22:23 |
| 27 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | zaterdag 14 september 2002 6:10 |
| 28 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | zaterdag 14 september 2002 16:44 |
| 29 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | zaterdag 14 september 2002 21:51 |
| 30 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | zondag 15 september 2002 12:43 |
| 31 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | zondag 15 september 2002 15:34 |
| 32 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | zondag 15 september 2002 17:26 |
| 33 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | maandag 16 september 2002 2:57 |
| 34 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | maandag 16 september 2002 3:10 |
| 35 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | donderdag 19 september 2002 11:06 |
| 36 "Stephen Speicher" |
Re: SR is succesfully debunked, spread the word. | donderdag 19 september 2002 23:47 |
| 37 "Spaceman" |
Re: SR is succesfully debunked, spread the word. | vrijdag 20 september 2002 17:21 |
| 38 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | woensdag 25 september 2002 14:18 |
| 39 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | dinsdag 8 oktober 2002 23:10 |
| 40 "rryker" |
Re: SR is succesfully debunked, spread the word. | woensdag 9 oktober 2002 0:33 |
| 41 "Nicolaas Vroom" |
Re: SR is succesfully debunked, spread the word. | woensdag 9 oktober 2002 21:07 |
| 42 "rryker" |
Re: SR is succesfully debunked, spread the word. | donderdag 10 oktober 2002 3:16 |
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
"Robert J. Kolker"
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.
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.
In the above thought experiment I wrote that the path between A and B
is straight.
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 ?
Nicolaas Vroom wrote:
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
"Robert J. Kolker"
Nicolaas Vroom wrote:
I expect you mean: is experimental incorrect.
Yes.
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
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.[1]
Bob Kolker
[1] Unless the discrepancy can be otherwise explained.
"Robert J. Kolker"
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:
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)
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.
Nick
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.
Bob Kolker
"Robert J. Kolker"
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
On Tue, 3 Sep 2002, Nicolaas Vroom wrote:
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?
--
Printed using 100% recycled electrons.
On Tue, 03 Sep 2002 05:59:57 GMT, "Nicolaas Vroom"
"Robert J. Kolker"
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!
I donīt think you can test these predictions without the other ones
happening. They are like both sides of a coin.
----
"Jan C. Bernauer"
"Robert J. Kolker"
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
On the dark and dreary 03 Sep 2002 Stephen Speicher
What and actually try to learn something about the subject?
--
Nicolaas Vroom wrote:
"Jan C. Bernauer"
"Robert J. Kolker"
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.
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
"Stephen Speicher"
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
On Wed, 4 Sep 2002, Nicolaas Vroom wrote:
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 ?
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
http://math.ucr.edu/home/baez/physics/Administrivia/rel_booklist.html
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.
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.
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.
--
Printed using 100% recycled electrons.
"Stephen Speicher"
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,
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.
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.
On Mon, 9 Sep 2002, Nicolaas Vroom wrote:
"Stephen Speicher"
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?
--
Printed using 100% recycled electrons.
"Nicolaas Vroom"
"Stephen Speicher"
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:
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.
On Wed, 11 Sep 2002, Nicolaas Vroom wrote:
"Nicolaas Vroom"
"Stephen Speicher"
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.
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.
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.
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
And observer A is on the bank of the track, not on the train.
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)."
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.
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.
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.
--
Printed using 100% recycled electrons.
"Nicolaas Vroom"
"Stephen Speicher"
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.
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
(Removing sci.physics. Do not cross-post!)
Jan Bielawski wrote:
"Nicolaas Vroom"
[snip]
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.
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.
On Thu, 12 Sep 2002, Russell Blackadar wrote:
Jan Bielawski wrote:
"Nicolaas Vroom"
[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?"
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.
--
Printed using 100% recycled electrons.
Stephen Speicher wrote:
On Thu, 12 Sep 2002, Russell Blackadar wrote:
(Removing sci.physics. Do not cross-post!)
Jan Bielawski wrote:
"Nicolaas Vroom"
[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
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3C3DFBA9.9BAB723B%40REMOVEmdli.com
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.
On Thu, 12 Sep 2002, Russell Blackadar wrote:
On Thu, 12 Sep 2002, Russell Blackadar wrote:
(Removing sci.physics. Do not cross-post!)
Jan Bielawski wrote:
"Nicolaas Vroom"
[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
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=3C3DFBA9.9BAB723B%40REMOVEmdli.com
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.
--
Printed using 100% recycled electrons.
Stephen Speicher wrote:
On Thu, 12 Sep 2002, Russell Blackadar wrote:
Stephen Speicher wrote:
[on whether Terrell rotation requires objects to be distant]
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.
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.
I do not wish to put myself up against all this literature,
since my arguments are quite naive, but really....
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.
"Stephen Speicher"
"Nicolaas Vroom"
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.
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.
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.
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:
d'Inverno also writes:
On the other hand in my opinion the drawing is only correct
for v=0. (See also your next reply)
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)
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.
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 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 have the book "A Journey into Gravity and Spacetime"
by Wheeler
On Fri, 13 Sep 2002, Nicolaas Vroom wrote:
[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.
--
Printed using 100% recycled electrons.
"Stephen Speicher"
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 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.
On Sat, 14 Sep 2002, Nicolaas Vroom wrote:
"Stephen Speicher"
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 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.
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.
--
Printed using 100% recycled electrons.
"Jan Bielawski"
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.
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
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.
I do not understand that within the frame of SR.
"Russell Blackadar"
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.
"Stephen Speicher"
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.
Hopefully your suggested litterature will solve this.
Nick
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.
--
Printed using 100% recycled electrons.
On Sun, 15 Sep 2002, Nicolaas Vroom wrote:
"Stephen Speicher"
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."
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.
You do not seem to understand plain English, much less
relativity.
The suggested literature explains relativity in a clear, rational
manner. Whether or not you choose to understand it is up to you.
--
Printed using 100% recycled electrons.
-----------------------------------------------------------
"Stephen Speicher"
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.
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.
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.
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.
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:
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.
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.
--
Printed using 100% recycled electrons.
-----------------------------------------------------------
Stephen Speicher sjs@compbio.caltech.edu wrote:
Translation,
In other words.
James M Driscoll Jr
"Stephen Speicher"
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:
For any one who wants to see a simulation of Terrell Rotation
please go to: https://www.nicvroom.be/terrell.htm
Nick
"Nicolaas Vroom"
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.
Nicolaas Vroom wrote:
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.
--
"rryker"
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......
This url does not work.
Nicolaas Vroom wrote:
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:
Back to my home page Contents of This Document
>
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 ?
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."
Consider that the path between A and B is slowly bended curved
at is always a distance R from the observer.
>
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
>
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
>
> >
SNIP
>
>
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
>
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
>
> >
>
>
Based on actual experiments:
is SR correct, is SR wrong or state undecided.
To be more specific:
Is length correction correct, wrong or undecided.
However because it is not possible to test length contraction
it is also not possible to test Relativity of simultaneity.
Can they perform such an test on earth ?
Can they perform such a test using space (ie a planet)
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
>
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
>
> >
>
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.
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
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
>
>>
>> >
>>
>
>
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.
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
>
On Tue, 03 Sep 2002 05:59:57 GMT, "Nicolaas Vroom"
> >
> >>
> >> >
> >>
> >
>
>
> >
>
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
>
You have been posting on this group (sci.physics.relativity) for
almost five years. Have you ever considered reading a text on
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
>
> >
On Tue, 03 Sep 2002 05:59:57 GMT, "Nicolaas Vroom"
> > >
> > >>
> > >> >
> > >>
> > >
> >
>
>
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.
>
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
>
On Tue, 3 Sep 2002, Nicolaas Vroom wrote:
> >
>
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"
> >
>
>
Where can I find the information about an experiment on
length contraction ?
>
>
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.
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
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
>
On Wed, 4 Sep 2002, Nicolaas Vroom wrote:
> >
(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.)
>
This document is avalaible at University of Antwerp
I will try to study it as soon as possible.
>
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 availble at Universtity in Hasselt (LUC)
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.
> >
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.
This book is availble at Universtity in Hasselt (LUC)
>
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
>
> >
>
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
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
>
> >
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.
Appearance of a moving meter stick.
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
>
> >
> > >
> >
This document is avalaible at University of Antwerp
I will try to study it as soon as possible.
>
>
Page 1043 discusses:
Appearance of a moving meter stick.
g Devices 1 and 2 (all in the rest frame or track frame)
>
identical
of the difference between the difference l between the two
Firinlength equal to the length of the carriage.
>
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.
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
20 Re: SR is succesfully debunked, spread the word.
Van: "Jan Bielawski"
Datum: donderdag 12 september 2002 3:19
>
"Nicolaas Vroom"
> >
> > >
> >
This document is avalaible at University of Antwerp
I will try to study it as soon as possible.
>
21 Re: SR is succesfully debunked, spread the word.
Van: "Russell Blackadar"
>
> >
My understanding of the aricle is that you can not
see (visible observe) length contraction in principle
>
>
Enough discernible surface detail would
also betray a net distortion, I think.
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!)
> >
>
> > >
> >
>
>
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.
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
23 Re: SR is succesfully debunked, spread the word.
Van: "Russell Blackadar"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 13 september 2002 3:55
>
> >
> > >
> >
> > > >
> > >
> >
>
>
> >
>
>
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:
> >
> > >
> > > >
> > >
> > > > >
> > > >
> > >
> >
>
> >
> > >
> >
>
> >
>
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
25 Re: SR is succesfully debunked, spread the word.
Van: "Russell Blackadar"
Onderwerp: Re: SR is succesfully debunked, spread the word.
Datum: vrijdag 13 september 2002 6:48
>
> >
>
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."
>
> > >
> >
>
>
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.
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
>
On Wed, 11 Sep 2002, Nicolaas Vroom wrote:
> >
>
> >
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)
>
> >
There is an Observer A in the middle between those two FD's
>
> >
>
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 ?
>
"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.
"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.
> >
(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.
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 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.
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
>
> >
>
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
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
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
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
>
> >
>
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
-----------------------------------------------------------
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
news:
>
"Nicolaas Vroom"
> >
My understanding of the aricle is that you can not
see (visible observe) length contraction in principle
>
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 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.
(Assuming one specific length l0 of the train)
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
>
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.
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
>
On Sat, 14 Sep 2002, Nicolaas Vroom wrote:
> >
>
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.
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
>
Stephen
sjs@compbio.caltech.edu
-----------------------------------------------------------
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 Sat, 14 Sep 2002, Nicolaas Vroom wrote:
> > >
> >
>
>
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.
Stephen
sjs@compbio.caltech.edu
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
>
On Wed, 11 Sep 2002, Nicolaas Vroom wrote:
> >
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 ?
SNIP
>
> >
IMO this setup is in principle a method to visible demonstrate
and to observe length contraction.
>
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.
Observer A near track, which stands in the middle
of those two marks sees those two flashes simultaneous.
IMO the answer is NO.
Hence, when one sees the cube to be overhead one will see
the Lorentz contraction of the bottom edge.
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
>
Stephen
sjs@compbio.caltech.edu
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.
for you to think "Sherlock Holmes was real"
you need to start from the beginnings and
read all his books.
:)
He wants you to "try and get brainwashed again"
:)
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
>
On Thu, 19 Sep 2002, Nicolaas Vroom wrote:
> >
>
or go to https://www.nicvroom.be/
and select and select question 7: Changing Length
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
>
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"
> >
>
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
>
> >
>
>
--
Rod Ryker...
It is reasoning and faith that bind truth.
http://herr_ryker.tripod.com/
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"
> >
> > >
> >
>
>
> >
>
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