Why Einstein Proposed That Speed Of Light Is Invariable....
jpk
is constant.
I believed that he reached that conclusion after Michelson Morley
experiment. But the fact is that, he postulated it before that
experiment.
Note: while posting your comments, please stick to the topic.
Dirk Van de moortel
8e761a07-3df3-4fbd...@f24g2000prh.googlegroups.com
> Let us discuss How Einstein come to the conclusion that speed of light
> is constant.
> I believed that he reached that conclusion after Michelson Morley
> experiment. But the fact is that, he postulated it before that
> experiment.
Michelson Morley: 1887
Einstein: 1905
>
> Note: while posting your comments, please stick to the topic.
Warning:
http://i263.photobucket.com/albums/ii144/assorted_mine/troll5d.jpg
Dirk Vdm
Mike
> Let us discuss How Einstein come to the conclusion that speed of light is constant.
Postulates are not a conclusion of anything. Conclusions can be
theorems, corrolalaries, etc.
> I believed that he reached that conclusion after Michelson Morley
> experiment. But the fact is that, he postulated it before that
> experiment.
So you think he was able to travel in time?
My suggestion:
The bell t[r]olls for thee.
Mike
Androcles
The raving lunatic said
the speed of light from A to B is c-v,
the speed of light from B to A is c+v,
the "time" taken each way is the same.
"the ``time'' required by light to travel from A to B equals the ``time''
it requires to travel from B to A."
"But the ray moves relatively to the initial point of k, when measured in
the stationary system, with the velocity c-v"
Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/
Note:
The ``time'' required by a turtle to travel from A to B equals the ``time''
it requires to travel from B to A,
but the turtle moves relatively to the initial point of k, when measured in
the stationary system, with the velocity
u-v.
The speed of turtles is a universal constant.
Any another insanity you wish to discuss? Yours perhaps?
Tom Roberts
> Let us discuss How Einstein come to the conclusion that speed of light
> is constant.
Einstein was enthralled by the beauty, elegance, and generality of
Maxwell's equations of electromagnetism, which were then just entering
into the physics curriculum. He noted that they predict that the speed
of an electromagnetic wave is c in whatever (inertial) coordinates are
used. As he had great faith in the Principle of Relativity, he explored
the possibility that both the PoR and Maxwell's equations are valid; SR
was the result. He phrased his postulates as he did in order to both
derive the desired result and make them acceptable to then-mainstream
physicists.
> I believed that he reached that conclusion after Michelson Morley
> experiment. But the fact is that, he postulated it before that
> experiment.
No. He was only 8 years old when they published. There were, however, in
1905 several then-current experiments that failed to find the aether of
Maxwell's theory. Lorentz and Poincare' (and others) were thinking along
similar lines in 1905 -- relativity was "in the air" at that time -- but
Einstein was the one that had the audacity to approach the problem in a
whole new say (no aether, re-definition of space and time).
BTW he did not propose "the speed of light is invariable", he postulated
that the speed of light is independent of the motion of its source. This
is an important distinction, because his phrasing was directly
accessible to his peers (being familiar with this property of aether
theories and Maxwell's equations); phrasing this in terms of
"invariance" came MUCH later.
Tom Roberts
papa...@gmail.com
I also like the explanation about this, given by Landau and Lifshitz
in their book "The Classical Theory of Fields", chapter 1, that reads:
“…experiment shows that instantaneous interactions do not exist in
nature. Thus a mechanics based on the assumption of instantaneous
propagation of interactions contains within itself a certain
inaccuracy. In actuality, if any change takes place in one of the
interacting bodies, it will influence the other bodies only after the
lapse of a certain interval of time. It is only after this time
interval that processes caused by the initial change begin to take
place in the second body. Dividing the distance between the two bodies
by this time interval, we obtain the velocity of propagation of the
interaction.
We note that this velocity should, strictly speaking, be called the
maximum velocity of propagation of interaction. It determines only
that interval of time after which a change occurring in one body
begins to manifest itself in another. It is clear that the existence
of a maximum velocity of propagation of interactions implies, at the
same time, that motions of bodies with greater velocity than this are
in general impossible in nature. For if such a motion could occur,
then by means of it one could realize an interaction with a velocity
exceeding the maximum possible velocity of propagation of
interactions.
Interactions propagating from one particle to another are frequently
called "signals", sent out from the first particle and "informing" the
second particle of changes which the first has experienced. The
velocity of propagation of interaction is then referred to as the
signal velocity.
From the principle of relativity it follows in particular that the
velocity of propagation of interactions is the same in all inertial
systems of reference. Thus the velocity of propagation of interactions
is a universal constant. This constant velocity (as we shall show
later) is also the velocity of light in empty space. The velocity of
light is usually designated by the letter c, and its numerical value
is……”
Miguel Rios
xxein
xxein: Thx Tom. Now you can see why nobody 'knows' anything
(including yourself). Source independency does not confer any other
attribute to light except the ability to function apart from the
source. Any other attributes are derived prematurely and separately
by various other notions of physics.
Hmm. Does an energy space exist within an empty space to guide such a
transaction of energy? Is this energy space static or is it flowing
of its own primordial volition?
Tom Roberts
> Source independency does not confer any other
> attribute to light except the ability to function apart from the
> source.
Hmm. That plus the PoR implies that the vacuum speed of light is
invariant (i.e. has the value c in any inertial frame). It is rather
silly to separate one statement from a theory and attempt to interpret
it apart from the rest of the theory....
As for any physical theory (which is a collection of mathematical
theorems and the interpretations of their symbols), one has many choices
for the set of equations one takes as postulates. Einstein selected his
postulates to accord with then-current theoretical expectations and
prejudices.
Today we can select a rather different set of postulates that completely
avoids criticisms about "assuming the speed of light is constant":
1) the PoR
2) pion beams exist
These are sufficient to derive all of SR, when combined with:
* the definition of inertial frames
* Einstein's "hidden postulates"
- clocks and rulers have no memory
- space is isotropic and homogeneous
- time is homogeneous and monotonic
* knowledge of what a pion is.
Einstein, of course, had no access to the last of these, nor sufficient
knowledge of group theory to apply them properly.
Indeed, SR became the first major application of group
theory in theoretical physics, first as a transformation
group (Lorentz invariance), and then as angular momentum
in non-relativistic quantum mechanics (!), and ultimately
in QED and other QFTs.
Today, with knowledge gained from GR, we can see the limitations of
inertial frames and the PoR. This relegates SR to being merely a LOCAL
theory.
Tom Roberts
Simple Simon
"Tom Roberts" <tjrobe...@sbcglobal.net> wrote in message
news:%O7Wj.3373$J16....@newssvr23.news.prodigy.net...
> xxein wrote:
> > Source independency does not confer any other
> > attribute to light except the ability to function apart from the
> > source.
>
> Hmm. That plus the PoR implies that the vacuum speed of light is
> invariant (i.e. has the value c in any inertial frame). It is rather
> silly to separate one statement from a theory and attempt to interpret
> it apart from the rest of the theory....
>
> As for any physical theory (which is a collection of mathematical
> theorems and the interpretations of their symbols), one has many choices
> for the set of equations one takes as postulates. Einstein selected his
> postulates to accord with then-current theoretical expectations and
> prejudices.
>
> Today we can select a rather different set of postulates that completely
> avoids criticisms about "assuming the speed of light is constant":
> 1) the PoR
> 2) pion beams exist
> These are sufficient to derive all of SR, when combined with:
> * the definition of inertial frames
> * Einstein's "hidden postulates"
> - clocks and rulers have no memory
I fail to understand the need to refer to clocks and rulers in the theory.
That is, the theory and relationships between relative temporal and spatial
displacements exists even if we didn't exist and weren't here to measure
them. The theory of their operation might be necessary to run experiments in
order to (in)validate a theory, but they are merely artifacts. No?
Mike
> > Let us discuss How Einstein come to the conclusion that speed of light
> > is constant.
>
> Einstein was enthralled by the beauty, elegance, and generality of
> Maxwell's equations of electromagnetism, which were then just entering
> into the physics curriculum. He noted that they predict that the speed
> of an electromagnetic wave is c in whatever (inertial) coordinates are
> used. As he had great faith in the Principle of Relativity, he explored
> the possibility that both the PoR and Maxwell's equations are valid; SR
> was the result. He phrased his postulates as he did in order to both
> derive the desired result and make them acceptable to then-mainstream
> physicists.
Tell the OP also that the principle of relativity combined with the
constancy of the speed of light result in paradoxical conclusions like
the bug-rivet paradox, the barn-pole paradox, the twin paradox etc.
Tell the OP also that the principle of relativity fails in the case of
acceleration, so it cannot be a principle of physics/ Acceleration is
absolute. When we have A and B observers moving towards eachother, and
one of them accelerates, things happen in his frame of reference that
do not happen in the frame that is moving inertially. Thus, the
principle does not apply.
Tell the OP also there is a set of theories that produce the same
predictions with SR but require neither the principle of relativity
nor the principle of the constancy of the speed of light.
Because when you tell a "story" it is good if it is complete and not
tailored to your agenda...
Mike
Pentcho Valev
sci.physics.rlativity:
Always devising new camouflage Roberts Roberts? Why do Einsteinians
need "a rather different set of postulates that completely avoids
criticisms about "assuming the speed of light is constant"? Are they
afraid of something? Old camouflage:
http://groups.google.com/group/sci.physics.relativity/browse_frm/thread/1cb971595bf0fe4?
If I were you Roberts Roberts, I would immediately adopt the
"different set of postulates" that Brother Jean Eisenstaedt offers:
http://ustl1.univ-lille1.fr/culture/publication/lna/detail/lna40/pgs/4_5.pdf
Jean Eisenstaedt: "Il n'y a alors aucune raison théorique à ce que la
vitesse de la lumière ne dépende pas de la vitesse de sa source ainsi
que de celle de l'observateur terrestre ; plus clairement encore, il
n'y a pas de raison, dans le cadre de la logique des Principia de
Newton, pour que la lumière se comporte autrement - quant à sa
trajectoire - qu'une particule matérielle. Il n'y a pas non plus de
raison pour que la lumière ne soit pas sensible à la gravitation.
Bref, pourquoi ne pas appliquer à la lumière toute la théorie
newtonienne ? C'est en fait ce que font plusieurs astronomes,
opticiens, philosophes de la nature à la fin du XVIIIème siècle. Les
résultats sont étonnants... et aujourd'hui nouveaux."
IN ENGLISH: "Therefore there is no theoretical reason why the speed of
light should not depend on the speed of the source and the speed of
the terrestrial observer as well; even more clearly, there is no
reason, in the framework of the logic of Newton's Principia, why light
should behave, as far as its trajectory is concerned, differently from
a material particle. Neither is there any reason why light should not
be sensible to gravitation. Briefly, why don't we apply the whole
Newtonian theory to light? In fact, that is what many astronomers,
opticians, philosophers of nature did by the end of 18th century. The
results are surprising....and new nowadays."
Pentcho Valev
pva...@yahoo.com
PD
> "Tom Roberts" <tjroberts...@sbcglobal.net> wrote in message
Yes and no.
The structure of spacetime is there with or without experiments, but
the laws of physics usually pertain to that which is *measured*. And
then you have to be careful about what you mean by certain things that
you measure -- such as length, duration, simultaneity. For physical
quantities that get measured, there is no useful independent meaning
other than through the essential elements of what the measurement
entails.
This key statement is central to the frame-dependence of some physical
quantities and the frame-independence of other physical quantities.
There are many here who believe that physical quantities must have
some absolute independence of measurement. This turns out to be not
so.
jpk
> Michelson Morley: 1887
> Einstein: 1905
Though Michelson Morley experiment was before 1905, Einstein's
theories doesn't depend on it. Actually he was unaware of that
experiment. Later Einstein told that Michaelson Morley experiment is a
confirmation of his theories....
I found it on one of the biography of Einstein.
jpk
> acceleration, so it cannot be a principle of physics/ Acceleration is
> absolute. When we have A and B observers moving towards eachother, and
> one of them accelerates, things happen in his frame of reference that
> do not happen in the frame that is moving inertially. Thus, the
> principle does not apply.
There are two versions of Relativity. 1)Special 2)General.
Special Theory of relativity deals with systems with constant
velocities(ie no accelerating systems considered).
General Theory of relativity deals with the acceleration and gravity,
and is applicable to any kind of systems. So special theory of
relativity becomes a specific situation of General Theory of
relativity(or General Theory of relativity includes Special Theory of
relativity).
So, Mike, what you said is right if we consider only special theory of
relativity. But General Theory of relativity precisely deals with the
accelerating bodies....
Tom Roberts
> I fail to understand the need to refer to clocks and rulers in the theory.
To be useful, a physical theory must relate to measurements. Clocks and
rulers are what we use to measure time intervals and distances.
> That is, the theory and relationships between relative temporal and spatial
> displacements exists even if we didn't exist and weren't here to measure
> them. The theory of their operation might be necessary to run experiments in
> order to (in)validate a theory, but they are merely artifacts. No?
Certainly the relationships hold whether they are measured or not, and
whether humans observe them or not. But it's not clear how to define
space or time intervals without rulers and clocks.
Tom Roberts
Tom Roberts
> Tell the OP also that the principle of relativity combined with the
> constancy of the speed of light result in paradoxical conclusions like
> the bug-rivet paradox, the barn-pole paradox, the twin paradox etc.
Hmmm. Be sure also to mention that the use of the word "paradox" here
means "seeming contradiction that turns out to NOT be a contradiction
upon analysis". These are cases where SR is fully consistent, but does
not conform to common sense -- that's OK, because common sense was not
developed with any phenomena involving speeds approaching c. The moral
is to NOT expect common sense to apply in regimes far removed from where
it was developed -- after all, flies _DO_ walk on the ceiling, and the
earth _IS_ round.
> Tell the OP also that the principle of relativity fails in the case of
> acceleration, so it cannot be a principle of physics/ Acceleration is
> absolute.
The PoR explicitly references inertial frames, and there can be no
relative acceleration between inertial frames. The PoR _CAN_ most
definitely be a principle of physics; with careful analysis one can
deduce from SR the way accelerated systems behave. Saying "acceleration
is absolute" involves a PUN on the 3rd word -- not all of the attributes
of "absolute" apply.
> When we have A and B observers moving towards eachother, and
> one of them accelerates, things happen in his frame of reference that
> do not happen in the frame that is moving inertially. Thus, the
> principle does not apply.
The PRINCIPLE still applies, but the physical situation you describe
does not meet the conditions of the principle. And you are confused --
things do not "happen" because of the accelerated frame, they happen
because of the mechanism used to accelerate the observer. The two
observers are in DIFFERENT PHYSICAL SITUATIONS and you cannot expect
them to observe things identically.
The phrasing of your last sentence could be interpreted as a general
claim, not specific to the physical situation you gave -- that's wrong,
and the PRINCIPLE is quite general, but not all physical situations meet
its conditions.
> Tell the OP also there is a set of theories that produce the same
> predictions with SR but require neither the principle of relativity
> nor the principle of the constancy of the speed of light.
But they require other, less appealing assumptions. Such as an
invisible, completely unobservable aether that magically controls
everything.
As I pointed out elsewhere in this thread, SR does not need to assume
the constancy of the speed of light. The only assumptions needed are the
PoR and some experimental fact that distinguishes the Lorentz group from
the Galilei group (plus a bunch of postulates that are not at issue
because every theory of this class assumes them).
> Because when you tell a "story" it is good if it is complete and not
> tailored to your agenda...
You need to take your own advice here. And you need to learn what SR
actually is.
Tom Roberts
Pentcho Valev
sci.physics.relativity:
> Mike wrote:
> > Tell the OP also that the principle of relativity combined with the
> > constancy of the speed of light result in paradoxical conclusions like
> > the bug-rivet paradox, the barn-pole paradox, the twin paradox etc.
>
> Hmmm. Be sure also to mention that the use of the word "paradox" here
> means "seeming contradiction that turns out to NOT be a contradiction
> upon analysis".
Of course Roberts Roberts. These are "paradoxes" only in Einstein
zombie world. In any other world they would not be contradictions;
they would be just "idiocies". Only in Einstein zombie world
"scientists" can trap a long train inside a short tunnel:
http://www.youtube.com/watch?v=VSRIyDfo_mY&mode=related&search
and also a 80m long pole inside a 40m long barn:
http://www.math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html
"These are the props. You own a barn, 40m long, with automatic doors
at either end, that can be opened and closed simultaneously by a
switch. You also have a pole, 80m long, which of course won't fit in
the barn....So, as the pole passes through the barn, there is an
instant when it is completely within the barn. At that instant, you
close both doors simultaneously, with your switch. Of course, you open
them again pretty quickly, but at least momentarily you had the
contracted pole shut up in your barn."
> These are cases where SR is fully consistent, but does
> not conform to common sense -- that's OK, because common sense was not
> developed with any phenomena involving speeds approaching c. The moral
> is to NOT expect common sense to apply in regimes far removed from where
> it was developed...
http://www.online-literature.com/orwell/1984/ George Orwell "1984":
"In the end the Party would announce that two and two made five, and
you would have to believe it. It was inevitable that they should make
that claim sooner or later: the logic of their position demanded it.
Not merely the validity of experience, but the very existence of
external reality, was tacitly denied by their philosophy. The heresy
of heresies was common sense. And what was terrifying was not that
they would kill you for thinking otherwise, but that they might be
right. For, after all, how do we know that two and two make four? Or
that the force of gravity works? Or that the past is unchangeable? If
both the past and the external world exist only in the mind, and if
the mind itself is controllable what then?"
Pentcho Valev
pva...@yahoo.com
Puppet_Sock
> On May 13, 5:19 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote in
> sci.physics.rlativity:
> > Today, with knowledge gained from GR, we can see the limitations of
> > inertial frames and the PoR. This relegates SR to being merely a LOCAL
> > theory.
>
> > Tom Roberts
>
> Always devising new camouflage Roberts Roberts?
You know, sensible people, intelligent people, sane people, can handle
that a person has a first and last name that are not the same. But I
suppose the notion of Tom Roberts overamps your tiny brain.
Go and learn something. Anything. Don't come back till you do.
Socks
Mike
> Mike wrote:
> > Tell the OP also that the principle of relativity combined with the
> > constancy of the speed of light result in paradoxical conclusions like
> > the bug-rivet paradox, the barn-pole paradox, the twin paradox etc.
>
> Hmmm. Be sure also to mention that the use of the word "paradox" here
> means "seeming contradiction that turns out to NOT be a contradiction
> upon analysis".
No. It is not saeemign contradiction, it is a violation of the law of
excluded middle. Either the bug is dead smashed by the river or not
dead.
> These are cases where SR is fully consistent, but does
> not conform to common sense -- that's OK, because common sense was not
> developed with any phenomena involving speeds approaching c. The moral
> is to NOT expect common sense to apply in regimes far removed from where
> it was developed -- after all, flies _DO_ walk on the ceiling, and the
> earth _IS_ round.
Listen, a theory that generates two contradictiory statements p and ~p
is inconcistent. You need to "refresh" your basics.
You argument is rediculus to say the least because it is a sophism. If
the laws of physics are to be the same in all moving inertial
reference frames so it should the underline common sense.
DO you think Roberts, common sense changes when approching the speed
of light? Do not try this at home.
But I sense what is happening here: YOu are responding like a defense
lawyer in a court, not as a true scientist. Won't get you too far.
> > Tell the OP also that the principle of relativity fails in the case of
> > acceleration, so it cannot be a principle of physics/ Acceleration is
> > absolute.
>
> The PoR explicitly references inertial frames, and there can be no
> relative acceleration between inertial frames. The PoR _CAN_ most
> definitely be a principle of physics; with careful analysis one can
> deduce from SR the way accelerated systems behave. Saying "acceleration
> is absolute" involves a PUN on the 3rd word -- not all of the attributes
> of "absolute" apply.
This is not linguistic aanalyis you are trying to turn it into. I
guess the same breed of people who mixed linguistic analysis with
physics and turned science into a mess use these arguments.
Ansolute here has an accepted meaning. It is not absolute vodka. It is
absolute in the sense that teh principle of relativity does not apply.
It is absolute, because it is NOT Relative.
> > When we have A and B observers moving towards eachother, and
> > one of them accelerates, things happen in his frame of reference that
> > do not happen in the frame that is moving inertially. Thus, the
> > principle does not apply.
>
> The PRINCIPLE still applies, but the physical situation you describe
> does not meet the conditions of the principle. And you are confused --
> things do not "happen" because of the accelerated frame, they happen
> because of the mechanism used to accelerate the observer. The two
> observers are in DIFFERENT PHYSICAL SITUATIONS and you cannot expect
> them to observe things identically.
I think you are confused. One cannot use a principle in physics and
then claim there are situations it does not apply.
Tell the stupid heads they distorted even the meaning of the term
principle that they shoudl merge physics and law schools.
>
> The phrasing of your last sentence could be interpreted as a general
> claim, not specific to the physical situation you gave -- that's wrong,
> and the PRINCIPLE is quite general, but not all physical situations meet
> its conditions.
I am sorry to see that you are proving again to be mor eof a lawyer
than a physicist.
>
> > Tell the OP also there is a set of theories that produce the same
> > predictions with SR but require neither the principle of relativity
> > nor the principle of the constancy of the speed of light.
>
> But they require other, less appealing assumptions. Such as an
> invisible, completely unobservable aether that magically controls
> everything.
Yet, they have no inconsistencies. A sane person should prefer an
invisible eather than an inconsistent theory full of paradoxes.
A deranged, insane man, will prefer a paradoxical theory.
Bith produce the same experimental predictions. People should know
that the price for not accepting an invisible aether IS TOO HIGH.
> As I pointed out elsewhere in this thread, SR does not need to assume
> the constancy of the speed of light. The only assumptions needed are the
> PoR and some experimental fact that distinguishes the Lorentz group from
> the Galilei group (plus a bunch of postulates that are not at issue
> because every theory of this class assumes them).
You are wrong in this. Many people have told you you are wrong. You
repeat this over and over. Your panic to escpae paradoxes forces you
to say funny things.
SR requires an upper speed limit of some kind. It turns out this is c.
If you do not consider the limit, you get some other theory, not
Einstein's.
Talking about experimental facts that have implicit justification
based on a constant c, is a ridiculus statement to make.
>
> > Because when you tell a "story" it is good if it is complete and not
> > tailored to your agenda...
>
> You need to take your own advice here. And you need to learn what SR
> actually is.
I studies SR already in my freshman year of college, ignoring protests
of professors that it was a senior course.
I studies SR before you decided to drop out of law school and to studt
physics. I never intended to study law or become a lawyer.
You are doing a good job at that.
SR should be taught in schools with great reservations, as one theory
of a general class of theories, because of its paradoxes, and GR
should be dropped altogether because it is falsified already.
But hey, maybe it's too early. Maybe that will take place during the
next Empire.
Mike
>
> Tom Roberts
Dirk Van de moortel
ea8d444e-1278-4f1c...@8g2000hse.googlegroups.com
[snip]
> A deranged, insane man, will prefer a paradoxical theory.
Actually, a deranged, insane man would be "hidding behind his
own ratten fingure", right?
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/RattenFingure.html
Dirk Vdm
Mike
SperM.hotmail.com> wrote:
> Mike <elea...@yahoo.gr> wrote in message
>
> ea8d444e-1278-4f1c-b602-678031585...@8g2000hse.googlegroups.com
>
> [snip]
>
> > A deranged, insane man, will prefer a paradoxical theory.
>
> Actually, a deranged, insane man would be "hidding behind his
> own ratten fingure", right?
or maybe a racist, an elementary algebra physicist wannabe, a square-
rooter, a chess player or a poster to alt.music.kylie.minogue:
http://groups.google.co.uk/group/sci.physics.relativity/msg/22f97e426496efb3=
http://groups.google.gr/group/sci.physics.relativity/msg/415dc591b91cad72?dm=
ode=3Dsource
http://groups.google.gr/group/sci.physics.relativity/msg/146912dbeef0d08b?dm=
ode=3Dsource
http://groups.google.gr/group/alt.jokes/msg/abd6fadea0a31456?dmode=3Dsource
http://groups.google.gr/group/rec.puzzles/msg/19bebf2b4b47a83e?dmode=3Dsourc=
e
You have been exposed loonie.
Mike
>
> Dirk Vdm
Simple Simon
>"Puppet_Sock" <puppe...@hotmail.com> wrote in message
news:178a0dd6-a05f-4606...@j22g2000hsf.googlegroups.com...
>On May 13, 2:40 am, Pentcho Valev <pva...@yahoo.com> wrote:
>> On May 13, 5:19 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote in
>> sci.physics.rlativity:
>[snip]
>> > Today, with knowledge gained from GR, we can see the limitations of
>> > inertial frames and the PoR. This relegates SR to being merely a LOCAL
>> > theory.
>>
>> > Tom Roberts
>>
>> Always devising new camouflage Roberts Roberts?
>[snip remaining crap]
>
>You know, sensible people, intelligent people, sane people, can handle
>that a person has a first and last name that are not the same. But I
>suppose the notion of Tom Roberts overamps your tiny brain.
I would expect puppet sock to refer to him as Bob Thomas.
Mike
[snip apologies]
>
> Today, with knowledge gained from GR, we can see the limitations of
> inertial frames and the PoR. This relegates SR to being merely a LOCAL
> theory.
"But your Honor, my client is not a thief, he just stole 'locally'"
Judge: "you should be jailed along with your client for trying to
differentiate between local and non-local theft"
SR is a local joke. GR is a global joke.
Mike
>
> Tom Roberts
Tom Roberts
> There are two versions of Relativity. 1)Special 2)General.
Yes. Moreover, SR is the local limit of GR, and is wholly contained in it.
> Special Theory of relativity deals with systems with constant
> velocities(ie no accelerating systems considered).
This is not true. One can easily use calculus to handle non-inertial
motion and non-inertial coordinate systems in SR.
What SR cannot handle is gravitation, and the curvature it introduces.
That requires GR.
> So, Mike, what you said is right if we consider only special theory of
> relativity.
No, it is not right.
Tom Roberts
Dono
> jpk wrote:
> > There are two versions of Relativity. 1)Special 2)General.
>
> Yes. Moreover, SR is the local limit of GR, and is wholly contained in it.
>
> > Special Theory of relativity deals with systems with constant
> > velocities(ie no accelerating systems considered).
>
> This is not true. One can easily use calculus to handle non-inertial
> motion and non-inertial coordinate systems in SR.
>
I have been trying to get a textbook that deals with SR in rotating
frames (I have plenty of experience with linearly uniformly
accelerated frames). I couldn't find anything, can you recommend a
book? Thanks
Tom Roberts
> On May 13, 10:58 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>> Mike wrote:
>>> Tell the OP also that the principle of relativity combined with the
>>> constancy of the speed of light result in paradoxical conclusions like
>>> the bug-rivet paradox, the barn-pole paradox, the twin paradox etc.
>> Hmmm. Be sure also to mention that the use of the word "paradox" here
>> means "seeming contradiction that turns out to NOT be a contradiction
>> upon analysis".
>
> No. It is not saeemign contradiction, it is a violation of the law of
> excluded middle.
No, it isn't. But you clearly do not understand SR sufficiently well to
know that. <shrug>
> Either the bug is dead smashed by the river or not
> dead.
I don't understand this. Perhaps it's related to your "bug-rivet
paradox", which I have never heard of.
> Listen, a theory that generates two contradictiory statements p and ~p
> is inconcistent.
I agree that such a theory is inconsistent. But SR never makes such
contradictory statements: A) nobody, including yourself, has ever
demonstrated such a contradiction in SR [#], B) it has been proven that
SR [@] is as self-consistent as is Euclidean geometry, C) it has been
proven that SR [@] is as self-consistent as is real analysis.
[#] The REAL theory known as SR, not a comic-book version.
[@] The underlying mathematics, including the Lorentz transform.
It is not possible to prove that SR applies to the world we
inhabit, or that inertial frames as defined do actually exist
(indeed they don't exist, but are only an approximation).
> If
> the laws of physics are to be the same in all moving inertial
> reference frames so it should the underline common sense.
What aspect of your common sense includes objects moving with speeds
faster than (say) 0.001 c?
Yes, in SR the laws of physics are the same in all moving inertial
frames, but that is irrelevant to the failure of your commons sense to
include relativistic effects. Those of us who DO work routinely with
such objects know that SR is absolutely essential in describing them
(modulo equivalences, of course).
> DO you think Roberts, common sense changes when approching the speed
> of light? Do not try this at home.
You need to improve the accuracy of your reading. I never said anything
like that. What aspect of your common sense includes objects moving with
speeds faster than (say) 0.001 c? When did YOU approach such a speed so
that you could test your common sense as such a speed?
> But I sense what is happening here: YOu are responding like a defense
> lawyer in a court, not as a true scientist. Won't get you too far.
You haven't a clue.... I cannot help it if the language you use is too
loose and ambiguous, forcing me to point out YOUR linguistic failures.
This is not "lawyerish", this is NECESSARY -- precision in language and
thought is absolutely essential to understand relativity.
>> Saying "acceleration
>> is absolute" involves a PUN on the 3rd word -- not all of the attributes
>> of "absolute" apply.
>
> This is not linguistic aanalyis you are trying to turn it into.
_I_ did not make that pun, YOU DID. And the discussion cannot continue
with such a pun being left unacknowledged.
> Ansolute here has an accepted meaning.
Not really. It has several accepted meanings, and not all of them apply.
> It is
> absolute in the sense that teh principle of relativity does not apply.
> It is absolute, because it is NOT Relative.
There are several types of acceleration. Some are invariant, some are
not (i.e. they are frame/observer/coordinate dependent). You attempt to
make a general statement when no such general statement can be made.
Yes, the property acceleration=0 is invariant and has the same value to
all observers, but the VALUE of a nonzero acceleration can be frame
dependent (e.g. the usual 3-acceleration), and the VALUE of acceleration
can be invariant (either proper acceleration or 4-acceleration).
>> The PRINCIPLE still applies, but the physical situation you describe
>> does not meet the conditions of the principle. And you are confused --
>> things do not "happen" because of the accelerated frame, they happen
>> because of the mechanism used to accelerate the observer. The two
>> observers are in DIFFERENT PHYSICAL SITUATIONS and you cannot expect
>> them to observe things identically.
>
> One cannot use a principle in physics and
> then claim there are situations it does not apply.
THAT'S WHAT I SAID!!! -- look at my first 4 words in that quotation.
The world does not consist of just inertial objects. The PoR EXPLICITLY
says it applies to inertial coordinate systems, and the WHOLE PRINCIPLE
always applies. But for non-inertial objects or coordinates one cannot
obtain anything useful from it. This is just basic logic:
The statement "for all a, B" means B applies to every a. But
it does not give any useful conclusion from !a. The PoR is
of this form, where a is "inertial coordinate system" and
!a is your accelerated observer. So the PoR APPLIES, but
does not say anything useful for that case. <shrug>
>> As I pointed out elsewhere in this thread, SR does not need to assume
>> the constancy of the speed of light. The only assumptions needed are the
>> PoR and some experimental fact that distinguishes the Lorentz group from
>> the Galilei group (plus a bunch of postulates that are not at issue
>> because every theory of this class assumes them).
>
> You are wrong in this. Many people have told you you are wrong.
Not true. This _IS_ correct, and nobody has ever "told me this is wrong"
and been able to support that claim. Nor have you.
> SR requires an upper speed limit of some kind. It turns out this is c.
> If you do not consider the limit, you get some other theory, not
> Einstein's.
Sure. And based on the postulates I mentioned earlier one can derive
such a speed limit. I cannot help it if you are unable to see it, it
_IS_ there. Admittedly it is subtle and rather far removed from those
postulates....
> Talking about experimental facts that have implicit justification
> based on a constant c, is a ridiculus statement to make.
How is the postulate "pion beams exist" based on c? To me it looks like
a claim about certain equipment at CERN, Fermilab, and many other
laboratories around the world, and the particles transported. No "c" there.
But if you don't like that second postulate, there are many other
possible choices:
2a: the Fermilab Tevatron works, the CERN SPS works, the ... works
2b: the GPS works (this one has thorns, as it involves GR)
2c: no object travels faster than c relative to an inertial frame
2d: no signal travels faster than c relative to an inertial frame
2e: there is a finite upper bound to any signal speed relative to
an inertial frame
2f: there is a finite upper bound to the relative speed between any
pair of inertial frames
In some ways, 2f is the easiest to work with....
> [... further nonsense]
Tom Roberts
Pentcho Valev
sci.physics.relativity:
Try first Divine Albert's Divine Analysis:
http://www.bartleby.com/173/23.html
Divine Albert: "Moreover, at this stage the definition of the space co-
ordinates also presents unsurmountable difficulties. If the observer
applies his standard measuring-rod (a rod which is short as compared
with the radius of the disc) tangentially to the edge of the disc,
then, as judged from the Galileian system, the length of this rod will
be less than 1, since, according to Section XII, moving bodies suffer
a shortening in the direction of the motion. On the other hand, the
measuring-rod will not experience a shortening in length, as judged
from K, if it is applied to the disc in the direction of the radius.
If, then, the observer first measures the circumference of the disc
with his measuring-rod and then the diameter of the disc, on dividing
the one by the other, he will not obtain as quotient the familiar
number pi = 3.14 …, but a larger number, whereas of course, for a disc
which is at rest with respect to K, this operation would yield pi
exactly."
Do you find Divine Albert's text silly? Extremely silly? Incredibly
silly? Do you know of Poincaré's text where exactly the same result
("...not obtain as quotient the familiar number pi = 3.14 …, but a
larger number....") is deduced from an esentially different thought
experiment (a disc which is heated, does not rotate etc.)? Was Divine
Albert in fact Divine Plagiarist who was not able to intoduce non-
Euclidean geometry in a way different fom Poincaré's:
Divine Plagiarist: "This proves that the propositions of Euclidean
geometry cannot hold exactly on the rotating disc, nor in general in a
gravitational field, at least if we attribute the length 1 to the rod
in all positions and in every orientation."
Pentcho Valev
pva...@yahoo.com
Mike
> Mike wrote:
> > On May 13, 10:58 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
> >> Mike wrote:
> >>> Tell the OP also that the principle of relativity combined with the
> >>> constancy of the speed of light result in paradoxical conclusions like
> >>> the bug-rivet paradox, the barn-pole paradox, the twin paradox etc.
> >> Hmmm. Be sure also to mention that the use of the word "paradox" here
> >> means "seeming contradiction that turns out to NOT be a contradiction
> >> upon analysis".
>
> > No. It is not saeemign contradiction, it is a violation of the law of
> > excluded middle.
>
> No, it isn't. But you clearly do not understand SR sufficiently well to
> know that. <shrug>
Please, do not start with an "appeal to ingorance" Any knind of appeal
is an informal fallacy. You need to prove in science.
>
> > Either the bug is dead smashed by the river or not
> > dead.
>
> I don't understand this. Perhaps it's related to your "bug-rivet
> paradox", which I have never heard of.
Funny, le tres savant Roberts have never heard of the bug-rivet
paradox:
Woooooooooooooooooooooaaaaaaaaaaaaaaaaaaaaaaouaaaaaaaaaaaaaaaa
You got some reading to do before we can continue talking. It seems
you have no clue:
http://hyperphysics.phy-astr.gsu.edu/Hbase/Relativ/bugrivet.html
Let me also record your post in my immortal fumbles list.
We relly cannot continue this conversation as you have demonstrated
severe lack of knowledge and only an urge to linguistically support
your dead theory with fallacies, presumptions, attacks on common
sense, distrortion of words, distortion of concepts, etc.
Mike
[snip out of context answers]
Mike
> jpk wrote:
> > There are two versions of Relativity. 1)Special 2)General.
>
> Yes. Moreover, SR is the local limit of GR, and is wholly contained in it.
There is no convincing proof that SR is the local limit of GR. ONLY AN
ASSUMPTION that the GR psacetime locally can be broken down to
Minkowski spacetime and a pertrubation.
WARNING; this is an assumption. sing an assumption as a conclusiuon is
called a petittio principii in logic, very severe form of fallacy.
>
> > Special Theory of relativity deals with systems with constant
> > velocities(ie no accelerating systems considered).
>
> This is not true. One can easily use calculus to handle non-inertial
> motion and non-inertial coordinate systems in SR.
>
Of course, but then the PoR and constancy of speed of light postulates
do not apply.
DO NOT come back and say they apply "locally' unless you define it and
prove it.
> What SR cannot handle is gravitation, and the curvature it introduces.
> That requires GR.
WAIT A SECOND. If SR is the local limit of GR, as you already
asserted, and SR cannot handle gravitation, what happens to gravity in
the WEAK FIELD LIMIT?
I know you will say it is described by Newton's law of gravitation.
Can I laugh? Why is it that the scientific community keeps up with
this kind of BS? It is beyond comprehension that soo many people keep
quite.
> > So, Mike, what you said is right if we consider only special theory of
> > relativity.
>
> No, it is not right.
Yes, it is right. You ahve not proven otherwise. You just want to
convince people by claiming some kind of authority on the subject
while you prove nothing. YOur statements are linguistic games. No
proofs of any kind. Don't refer to pion beams. Those are not proofs of
your ridiculus claims.
Mike
> Tom Roberts
Tom Roberts
> I have been trying to get a textbook that deals with SR in rotating
> frames (I have plenty of experience with linearly uniformly
> accelerated frames). I couldn't find anything, can you recommend a
> book? Thanks
I don't know of any. MTW discusses the (lack of) redshift for a light
signal sent from one point to any other point on the rim of a rotating
disk. But that's the only example I'm sure of.
There is a rather larger literature on this, but beware that some
papers, even in reputable journals, have mistakes (typos, algebra
errors, and at least one has a gross conceptual blunder).
Tom Roberts
Dono
Thank you,
This is surprising ....and disappointing. I found one book of
collected papers but no consistent treatment.
http://digilander.libero.it/solciclos/
Not clear how many of the papers are serious and how many are crackpot
in the above....
Tom Roberts
> On May 13, 7:41 pm, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>> jpk wrote:
>>> There are two versions of Relativity. 1)Special 2)General.
>> Yes. Moreover, SR is the local limit of GR, and is wholly contained in it.
>
> There is no convincing proof that SR is the local limit of GR. ONLY AN
> ASSUMPTION that the GR psacetime locally can be broken down to
> Minkowski spacetime and a pertrubation.
This is just plain not true. In any manifold, one can always find
Riemann normal coordinates at any point. In GR, those coordinates are
the Minkowski coordinates of a locally-inertial frame. It is RIGOROUSLY
TRUE that SR is the local limit of GR in this sense. There is no
"assumption" here, this is one of the properties of the semi-Riemannian
manifolds used in GR (in essence this is part of the definition of
"manifold").
If you are going to try to discuss these theories, you REALLY should
learn what they are. You display a serious ignorance of the basics of
both SR and GR.
>>> Special Theory of relativity deals with systems with constant
>>> velocities(ie no accelerating systems considered).
>> This is not true. One can easily use calculus to handle non-inertial
>> motion and non-inertial coordinate systems in SR.
>
> Of course, but then the PoR and constancy of speed of light postulates
> do not apply.
This depends on what you mean by "apply". Both postulates state
properties of inertial frames, which clearly need not hold for
non-inertial frames.
> DO NOT come back and say they apply "locally' unless you define it and
> prove it.
Both postulates are of the from "for all a, B", where a is "inertial
frames" and B is a specific statement about them. Non-inertial frames
are !a, and so while the postulates logically apply, one obtains no
useful inference from them for the case of non-inertial frames. <shrug>
To be clear, I mean Einstein's original postulates.
>> What SR cannot handle is gravitation, and the curvature it introduces.
>> That requires GR.
>
> WAIT A SECOND. If SR is the local limit of GR, as you already
> asserted, and SR cannot handle gravitation, what happens to gravity in
> the WEAK FIELD LIMIT?
SR is NOT the weak field limit of GR. It is the LOCAL limit.
What happens is that in the weak field limit, with v/c<<1 for all
objects, one can use "background" Minkowski coordinates and express the
metric to lowest order in small quantities such that only the g_tt
component differs from Minkowski (involving \phi, the Newtonian
gravitational potential); the Einstein field equation reduces to
Poisson's equation and the grad \phi = dp/dt of Newtonian mechanics. The
assumptions of this limit require that the size of the volume of
spacetime be small compared to the typical curvature radius of the
manifold; near earth that is on the order of a light year, so this can
be used accurately for the solar system but not the galaxy.
The TimeLord
8e761a07-3df3-4fbd...@f24g2000prh.googlegroups.com:
> Let us discuss How Einstein come to the conclusion that speed of light
> is constant.
> I believed that he reached that conclusion after Michelson Morley
> experiment. But the fact is that, he postulated it before that
> experiment.
Albert Einstein was asked about that. His claim was that he didn't know
about the Michelson-Morley Experiment as he was thinking about Relativity.
>
> Note: while posting your comments, please stick to the topic.
I try.
Mike
> Mike wrote:
> > On May 13, 7:41 pm, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
> >> jpk wrote:
> >>> There are two versions of Relativity. 1)Special 2)General.
> >> Yes. Moreover, SR is the local limit of GR, and is wholly contained in it.
>
> > There is no convincing proof that SR is the local limit of GR. ONLY AN
> > ASSUMPTION that the GR psacetime locally can be broken down to
> > Minkowski spacetime and a pertrubation.
>
> This is just plain not true. In any manifold, one can always find
> Riemann normal coordinates at any point. In GR, those coordinates are
> the Minkowski coordinates of a locally-inertial frame. It is RIGOROUSLY
> TRUE that SR is the local limit of GR in this sense. There is no
> "assumption" here, this is one of the properties of the semi-Riemannian
> manifolds used in GR (in essence this is part of the definition of
> "manifold").
>
> If you are going to try to discuss these theories, you REALLY should
> learn what they are. You display a serious ignorance of the basics of
> both SR and GR.
You will get embarashed once more because you underestimate your
opponents and you continuously fall into traps you create for
yourself.
You should agree that a Theory is a set of principles (can be a set of
axioms and empirical statements) from which all theorems and
predictions of the theory can be derived.
Now, having said that, listen carefully: Physics is not just plain
geometry. What you say is true but SR has 4 principles. Starting from
GR, without any knowledge of SR, one can only derive the first
principle dealing with the geometry of spacetime:
Principle 1: Spacetime is a 4-D continuum. Indeed, one can show that
locally, this principle can be derived from GR.
BUT YOU CANNOT DERIVE SR. To derive locally SR from GR you must also
derive the following principles:
(2) There are globally inertial reference frames
(3) PoR
(4) Constancy of c in all globally IFoR
Actually, (2) cannot be rived at all, since one is working locally
only.
(3) Cannot be derived at all from GR, since at a local limit paradoxes
arise, like bug-river paradox and anti-symmetrical situation that
defeat the PoR.
(4) You need to make assumptions to derive constancy of c. Actually, I
do not think is can be derived, since the principle deals with
constancy of c is ALL GLOBALLY INERTIAL FoR and locally such
conclusion cannot be derived.
Now you see, how naive you are. Physics is not just geometry. It does
not suffice to reduce one maniford to another to go from one theory to
another. It requires much more.
There is more to physical theories than geometry. Your expertise in
topology will gets you nowhere with me, only with people you can
succeed to intimidate from start by attacking their knoweledge about
the subject.
> >>> Special Theory of relativity deals with systems with constant
> >>> velocities(ie no accelerating systems considered).
> >> This is not true. One can easily use calculus to handle non-inertial
> >> motion and non-inertial coordinate systems in SR.
>
> > Of course, but then the PoR and constancy of speed of light postulates
> > do not apply.
>
> This depends on what you mean by "apply". Both postulates state
> properties of inertial frames, which clearly need not hold for
> non-inertial frames.
>
> > DO NOT come back and say they apply "locally' unless you define it and
> > prove it.
>
> Both postulates are of the from "for all a, B", where a is "inertial
> frames" and B is a specific statement about them. Non-inertial frames
> are !a, and so while the postulates logically apply, one obtains no
> useful inference from them for the case of non-inertial frames. <shrug>
The above statement is pure non-sense.
>
> To be clear, I mean Einstein's original postulates.
>
> >> What SR cannot handle is gravitation, and the curvature it introduces.
> >> That requires GR.
>
> > WAIT A SECOND. If SR is the local limit of GR, as you already
> > asserted, and SR cannot handle gravitation, what happens to gravity in
> > the WEAK FIELD LIMIT?
>
> SR is NOT the weak field limit of GR. It is the LOCAL limit.
Who said so? It's not the local limit and NM is not the weak field
limit either. relativists have succeeded to fool so many people, it's
mind boggling.
[snip apologetic talk]
Mike
Dirk Van de moortel
> On May 14, 10:48 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>> Mike wrote:
>>> On May 13, 7:41 pm, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>>>> jpk wrote:
>>>>> There are two versions of Relativity. 1)Special 2)General.
>>>> Yes. Moreover, SR is the local limit of GR, and is wholly contained in it.
>>
>>> There is no convincing proof that SR is the local limit of GR. ONLY AN
>>> ASSUMPTION that the GR psacetime locally can be broken down to
>>> Minkowski spacetime and a pertrubation.
>>
>> This is just plain not true. In any manifold, one can always find
>> Riemann normal coordinates at any point. In GR, those coordinates are
>> the Minkowski coordinates of a locally-inertial frame. It is RIGOROUSLY
>> TRUE that SR is the local limit of GR in this sense. There is no
>> "assumption" here, this is one of the properties of the semi-Riemannian
>> manifolds used in GR (in essence this is part of the definition of
>> "manifold").
>>
>> If you are going to try to discuss these theories, you REALLY should
>> learn what they are. You display a serious ignorance of the basics of
>> both SR and GR.
>
> You will get embarashed once more because you underestimate your
> opponents and you continuously fall into traps you create for
> yourself.
I think that Tom wildly OVER-estimates his "opponents".
Here is what his current "opponent" has in store:
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/BrainHoles.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/StudyReason.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/AndroclesTeach.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Physics101quater.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Physics101ter.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Physics101bis.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Physics101.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Sociology.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/IdiotsAndrocles.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/RattenFingure.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/StockWithIt.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/EleatisStyle.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/OfCourseBozzo.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Bourbaki.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Psychotic.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Learned.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Playground.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Dirt.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/Imbecile.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/HiPsycho.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/DinkDonk.html
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/RealTroubles.html
Some "oppenent" :-)
Dirk Vdm
Mike
>
>
>
>
>
> > On May 14, 10:48 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
> >> Mike wrote:
> >>> On May 13, 7:41 pm, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
> >>>> jpk wrote:
> >>>>> There are two versions of Relativity. 1)Special 2)General.
> >>>> Yes. Moreover, SR is the local limit of GR, and is wholly contained in it.
>
> >>> There is no convincing proof that SR is the local limit of GR. ONLY AN
> >>> ASSUMPTION that the GR psacetime locally can be broken down to
> >>> Minkowski spacetime and a pertrubation.
>
> >> This is just plain not true. In any manifold, one can always find
> >> Riemann normal coordinates at any point. In GR, those coordinates are
> >> the Minkowski coordinates of a locally-inertial frame. It is RIGOROUSLY
> >> TRUE that SR is the local limit of GR in this sense. There is no
> >> "assumption" here, this is one of the properties of the semi-Riemannian
> >> manifolds used in GR (in essence this is part of the definition of
> >> "manifold").
>
> >> If you are going to try to discuss these theories, you REALLY should
> >> learn what they are. You display a serious ignorance of the basics of
> >> both SR and GR.
>
> > You will get embarashed once more because you underestimate your
> > opponents and you continuously fall into traps you create for
> > yourself.
>
> I think that Tom wildly OVER-estimates his "opponents".
I agree wuth that.
By the way, are you a racist, an imbecile, a square-rooter, a chess-
player, a minogue fan?
http://groups.google.co.uk/group/sci.physics.relativity/msg/22f97e426496efb3=3D
http://groups.google.gr/group/sci.physics.relativity/msg/415dc591b91cad72?dmode=3D3Dsource
http://groups.google.gr/group/sci.physics.relativity/msg/146912dbeef0d08b?dmode=3D3Dsource
http://groups.google.gr/group/alt.jokes/msg/abd6fadea0a31456?dmode=3D3Dsource
http://groups.google.gr/group/rec.puzzles/msg/19bebf2b4b47a83e?dmode=3D3Dsource
Eric Gisse
[snip]
Why don't you open a textbook on GR and explore the section that
discusses Riemann normal coordinates?
Pentcho Valev
> On May 13, 10:10 pm, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>
> > Mike wrote:
> > > Either the bug is dead smashed by the river or not
> > > dead.
>
> > I don't understand this. Perhaps it's related to your "bug-rivet
> > paradox", which I have never heard of.
>
> Funny, le tres savant Roberts have never heard of the bug-rivet
> paradox:
>
> Woooooooooooooooooooooaaaaaaaaaaaaaaaaaaaaaaouaaaaaaaaaaaaaaaa
>
> You got some reading to do before we can continue talking. It seems
> you have no clue:
>
> http://hyperphysics.phy-astr.gsu.edu/Hbase/Relativ/bugrivet.html
>
> Let me also record your post in my immortal fumbles list.
Note that Roberts is the only Einsteinian that would discuss barn-
pole, bug-rivet etc. idiotic corollaries of Einstein's 1905 false
light postulate. All other Einsteinans have been silent for a long
time and some of them have officially abandoned Einstein cult. So let
us appreciate Roberts' courage.
Pentcho Valev
pva...@yahoo.com
Tom Roberts
>> Mike wrote:
>>> Either the bug is dead smashed by the river or not
>>> dead.
OK. That is a rather bad gedanken, because a) it assumes seriously
impossible properties of the rivet, and b) there is no inertial frame in
which the rivet REMAINS at rest. I have no desire to discuss it because
it is so bad. That's probably why I had forgotten it.
If you want to discuss the pole-barn paradox, be sure to use the version
that has equal-length barn and pole (in their respective rest frames),
with barn door 1 initially closed and door 2 initially open. The pole
enters through door 2, and immediately after the back of the pole passes
door 2 it is closed and then door 1 is opened (VERY short delay, VERY
fast doors). So the pole sails through without ever touching either
door, yet there was an instant in the barn frame when both doors were
closed and the (shortened) pole was between them. In the pole frame, of
course, this is described as door 1 opening before the front of the pole
reaches it, and there is a period of time during which both barn doors
are open and the (unshortened) pole slides through the (shortened) barn
with both doors open; after the back of the pole passes door 1 it closes
and the pole continues out of the barn.
My point is: some things are reasonable to assume in a gedanken, and
some are not. It is reasonable to assume that doors can open and close
arbitrarily quickly, because they need not really be physical doors. But
it is not reasonable to assume a rivet is prefectly rigid, because that
is inconsistent with SR (the speed of sound cannot exceed the speed of
light, which makes a perfectly rigid object impossible). And it is not
reasonable in a gedanken to expect the student to wrestle with
accelerating frames (such as that of the rigid rivet after its head
stops by hitting the wall).
Of course in the bug-and-rivet gedanken, if one does not
assume infinitely-rigid rivet and wall, the bug is
always crushed as the rivet and wall disintegrate upon
impact. A 10-gram rivet traveling at 0.9 c would have a
kinetic energy comparable to that of a small atomic bomb.
Tom Roberts
Mike
> Mike wrote:
> >> Mike wrote:
> >>> Either the bug is dead smashed by the river or not
> >>> dead.
> >http://hyperphysics.phy-astr.gsu.edu/Hbase/Relativ/bugrivet.html
>
> OK. That is a rather bad gedanken, because a) it assumes seriously
> impossible properties of the rivet, and b) there is no inertial frame in
> which the rivet REMAINS at rest. I have no desire to discuss it because
> it is so bad. That's probably why I had forgotten it.
A) Nothing impossible is assumes. It is a straight forward situation.
Istead of a bug you can have a switch to turn on a light.
B) For God's shake. What a panic excuse is that? The river is at rest
in it's own frame. It moves uniformly towards the bug.
You have no desire to discuss it because even hypephysics falsifies
your statement.
And you forget what does not suit your agenda.
SR IS AN INCONSISTENT PHYSICAL THEORY.
FOR HOW LONG WILL THE SCIENTIFIC COMMUNITY CONTINUE TO WORSHIP AN
INCONSISTENT THEORY ABOUT PHYSICAL REALITY?
FOR HOW LONG WILL THE SCIENTIFIC COMMUNITY CONTINUE TO BE SERVANTS OF
UNSCIENTIFIC AGENDAS?
SR IS A SPECIFIC INCONSISTENT THEORY OUT OF A GENERAL CLASS OF
THEORIES THAT ALL PRODUCE THE SAME EXPERIMENTAL PREDICTIONS BUT WITH
THE IMPORTANT DISTINCTION THAT SOME OF THEM ARE NOT INCONSISTENT.
Mike
Albertito
Don't worry about that, Mike, the bug-rivet paradox
will be brilliantly resolved by a relativist claiming there
will be a bifurcation of the reality into two parallel worlds.
In one of those worlds, the bug is smashed by the
rivet, and in the other it isn't. The former world will
be that of the proper bug's frame, and the latter will
be that of the proper rivet's frame. For each paradox
in SR, there always will be at least a suitable branching
of reality into as many parallel worlds as required :-)
Pentcho Valev
sci.physics.relativity:
Roberts Roberts the irrelevancy and idiocy of your last argument (Tom
Roberts: "the bug is always crushed as the rivet and wall disintegrate
upon impact") can be seen even by the silliest zombies in Einstein
criminal cult, and you are not among them. So the question is: Why are
you so dishonest Roberts Roberts?
Pentcho Valev
pva...@yahoo.com
Tom Roberts
> A) Nothing impossible is assumes.
Yes, a perfectly rigid rivet and wall are assumed, which are impossible
in SR, and TO APPLY SR one cannot assume things that are IMPOSSIBLE IN
SR. Without those assumptions, the bug is always crushed as rivet and
wall disintegrate on impact. <shrug>
> Istead of a bug you can have a switch to turn on a light.
Then the switch is destroyed, perhaps making contact, perhaps not.
> B) The river is at rest
> in it's own frame. It moves uniformly towards the bug.
Not once its rigid head hits the rigid wall and forces the rivet head to
stop instantaneously, while the body of the RIGID rivet continues moving
for a (very) short time. Rigidity normally applies in the rivet rest
frame, but during the interval just after the head stops at the wall,
the ENTIRE rivet is not at rest in any inertial frame. THAT'S one reason
why this is such a bad gedanken (assuming rigidity is another such reason).
> You have no desire to discuss it because even hypephysics falsifies
> your statement.
As I said, I have no desire to discuss it as it makes such unreasonable
assumptions. Ones that are INCONSISTENT with SR. <shrug>
> SR IS AN INCONSISTENT PHYSICAL THEORY.
You need to show this. Nobody has ever done so, and it has been proved
that it is impossible to do so (unless you can similarly show an
inconsistency in Euclidean geometry and also real analysis). <shrug>
Making impossible assumptions, such as rigid rivet and wall, show an
inconsistency IN THE GEDANKEN, not in SR itself.
> FOR HOW LONG WILL THE SCIENTIFIC COMMUNITY CONTINUE TO WORSHIP AN
> INCONSISTENT THEORY ABOUT PHYSICAL REALITY?
No "worship" is involved. UNDERSTANDING is the proper word.
Unfortunately, that seems to be beyond you. So STUDY. Or find another hobby.
Tom Roberts
Mike
> Mike wrote:
> > A) Nothing impossible is assumes.
>
> Yes, a perfectly rigid rivet and wall are assumed, which are impossible
> in SR, and TO APPLY SR one cannot assume things that are IMPOSSIBLE IN
> SR. Without those assumptions, the bug is always crushed as rivet and
> wall disintegrate on impact. <shrug>
hahahahahahahahaha
>
> > Istead of a bug you can have a switch to turn on a light.
>
> Then the switch is destroyed, perhaps making contact, perhaps not.
>
> > B) The river is at rest
> > in it's own frame. It moves uniformly towards the bug.
>
> Not once its rigid head hits the rigid wall and forces the rivet head to
> stop instantaneously, while the body of the RIGID rivet continues moving
> for a (very) short time. Rigidity normally applies in the rivet rest
> frame, but during the interval just after the head stops at the wall,
> the ENTIRE rivet is not at rest in any inertial frame. THAT'S one reason
> why this is such a bad gedanken (assuming rigidity is another such reason).
hahahahahahahahahahaha
> > You have no desire to discuss it because even hypephysics falsifies
> > your statement.
>
> As I said, I have no desire to discuss it as it makes such unreasonable
> assumptions. Ones that are INCONSISTENT with SR. <shrug>
hahahahahahahahahahahaha
> > SR IS AN INCONSISTENT PHYSICAL THEORY.
>
> You need to show this. Nobody has ever done so, and it has been proved
> that it is impossible to do so (unless you can similarly show an
> inconsistency in Euclidean geometry and also real analysis). <shrug>
>
> Making impossible assumptions, such as rigid rivet and wall, show an
> inconsistency IN THE GEDANKEN, not in SR itself.
hahahahahahahahahaha
> > FOR HOW LONG WILL THE SCIENTIFIC COMMUNITY CONTINUE TO WORSHIP AN
> > INCONSISTENT THEORY ABOUT PHYSICAL REALITY?
>
> No "worship" is involved. UNDERSTANDING is the proper word.
> Unfortunately, that seems to be beyond you. So STUDY. Or find another hobby.
IT appears that yout hobby is to try to defend inconsistent theories
in a remarkably hillarious way.
Get serious, drop either the PoR or the constancy of c or both. Be
brave, or find another hobby.
and while we are on that, don't ever tell anyone on a rollocoster that
force they FEEL is an artifact of reference frame.
IT THE CENTRIFUGAL FORCE. More tahn real, regardless of whether or not
some succeeded to take down the NASA page declaring so.
THERE IS NOTHING FICTICIOUS ABOUT THE BULDGE OF THE EARTH AT THE
EQUATOR.
hahahahahahahaha
sci.physcis.relativity is a lot of fun.
Mike
>
> Tom Roberts
Mike
I will be very dissapointed but since his last statement I think there
may be an issue of dishonesty here, something I did not want to accept
before.
However, I am thinking: how come so many people ware controlled by so
few and cannot voice their concerns.
The argument about all SR predictions being validated or so has
nothing to do. These are also the predictions of a general class of
theories that do not use contancy of c.
What's going on?
Mike
>
> Pentcho Valev
> pva...@yahoo.com- Hide quoted text -
>
> - Show quoted text -
Mike
>
> - Show quoted text -
Hmmmm.... those others cannot claim expert stautus in here. Give it a
few days and the hyperphysics web page with the paradox will be down.
Just save a copy for reference. Same happened to NASA page that
insisted there is nothing ficticious about the centrifugal force since
the effects are very real. Page is down since the discussion here.
Something is going on.
Mike
Pentcho Valev
I have referred to Big Brother's story too many times but, in my view,
Orwell's explanation remains closest to the truth:
http://www.online-literature.com/orwell/1984/ George Orwell "1984":
"In the end the Party would announce that two and two made five, and
you would have to believe it. It was inevitable that they should make
that claim sooner or later: the logic of their position demanded it.
Not merely the validity of experience, but the very existence of
external reality, was tacitly denied by their philosophy. The heresy
of heresies was common sense. And what was terrifying was not that
they would kill you for thinking otherwise, but that they might be
right. For, after all, how do we know that two and two make four? Or
that the force of gravity works? Or that the past is unchangeable? If
both the past and the external world exist only in the mind, and if
the mind itself is controllable what then?"
Pentcho Valev
pva...@yahoo.com
Mike
> "In the end the Party would announce that two and two made five, and
> you would have to believe it. It was inevitable that they should make
> that claim sooner or later: the logic of their position demanded it.
> Not merely the validity of experience, but the very existence of
> external reality, was tacitly denied by their philosophy. The heresy
> of heresies was common sense. And what was terrifying was not that
> they would kill you for thinking otherwise, but that they might be
> right. For, after all, how do we know that two and two make four? Or
> that the force of gravity works? Or that the past is unchangeable? If
> both the past and the external world exist only in the mind, and if
> the mind itself is controllable what then?"
>
> Pentcho Valev
>
> - Show quoted text -
Is that maybe why there is a parallel effort to convince people that
reality is mind created?
In such reality, the bug can be dead and not dead, depending on
reference frame, as it is that cat in QM, dead and alive, both when
nobody is looking.
I think we need more psychiatric clinics than universities.
Mike
Dirk Van de moortel
7f4c4a44-d649-4087...@u36g2000prf.googlegroups.com
Because he can't even do calculation problems for 10 years olds:
http://users.telenet.be/vdmoortel/dirk/Physics/Fumbles/BrainHoles.html
Dirk Vdm
Dirk Van de moortel
UPWWj.3341$7k7....@flpi150.ffdc.sbc.com
> Mike wrote:
[snip]
>> FOR HOW LONG WILL THE SCIENTIFIC COMMUNITY CONTINUE
>> TO WORSHIP AN
>> INCONSISTENT THEORY ABOUT PHYSICAL REALITY?
>
> No "worship" is involved. UNDERSTANDING is the proper word.
> Unfortunately, that seems to be beyond you. So STUDY. Or find another hobby.
Tom, his current hobby is "Trying to upset you" :-)
Dirk Vdm
PD
> Mike wrote:
> > A) Nothing impossible is assumes.
>
> Yes, a perfectly rigid rivet and wall are assumed, which are impossible
> in SR, and TO APPLY SR one cannot assume things that are IMPOSSIBLE IN
> SR. Without those assumptions, the bug is always crushed as rivet and
> wall disintegrate on impact. <shrug>
And in fact, perfectly rigid objects are impossible not only in SR but
also among the other laws of physics. (And in fact, a moment's thought
will tell you that SR is little more than the invocation of the laws
of physics and the principle of relativity.) This is true not just as
a practical matter but even in principle. There are several puzzles in
relativity that explicitly remind the student that rigidity is
inherently anathema in the real world.
mitch.nico...@gmail.com
> Let us discuss How Einstein come to the conclusion that speed of light
> is constant.
> I believed that he reached that conclusion after Michelson Morley
> experiment. But the fact is that, he postulated it before that
> experiment.
>
The speed of light is absolute through uncontracting space. This is
Einstein's constancy.
Mike
> On May 15, 8:23 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>
> > Mike wrote:
> > > A) Nothing impossible is assumes.
>
> > Yes, a perfectly rigid rivet and wall are assumed, which are impossible
> > in SR, and TO APPLY SR one cannot assume things that are IMPOSSIBLE IN
> > SR. Without those assumptions, the bug is always crushed as rivet and
> > wall disintegrate on impact. <shrug>
>
> And in fact, perfectly rigid objects are impossible not only in SR but
> also among the other laws of physics. (And in fact, a moment's thought
> will tell you that SR is little more than the invocation of the laws
> of physics and the principle of relativity.) This is true not just as
> a practical matter but even in principle. There are several puzzles in
> relativity that explicitly remind the student that rigidity is
> inherently anathema in the real world.
You sound full of tears...
What real world? This is a mathematical inconsistency illustrated by
an example.
Don't cry now. You want to go back and change all of mechanics?
T+You do not seem to say the same things about falling elevators and
the "feel" that free fall = acceleration.
When it suits you, you get as anthropocentri as you want, mixing
physics with feelings and perception.
This attitude will gets you nowhere.
Prety soon some Chineese or Indian who is not threatened by the
establishement with losing his job will falsify you experimentally.
Physical theories are associated with empire rise and fall...
Mike
>
>
>
>
>
> > > Istead of a bug you can have a switch to turn on a light.
>
> > Then the switch is destroyed, perhaps making contact, perhaps not.
>
> > > B) The river is at rest
> > > in it's own frame. It moves uniformly towards the bug.
>
> > Not once its rigid head hits the rigid wall and forces the rivet head to
> > stop instantaneously, while the body of the RIGID rivet continues moving
> > for a (very) short time. Rigidity normally applies in the rivet rest
> > frame, but during the interval just after the head stops at the wall,
> > the ENTIRE rivet is not at rest in any inertial frame. THAT'S one reason
> > why this is such a bad gedanken (assuming rigidity is another such reason).
>
> > > You have no desire to discuss it because even hypephysics falsifies
> > > your statement.
>
> > As I said, I have no desire to discuss it as it makes such unreasonable
> > assumptions. Ones that are INCONSISTENT with SR. <shrug>
>
> > > SR IS AN INCONSISTENT PHYSICAL THEORY.
>
> > You need to show this. Nobody has ever done so, and it has been proved
> > that it is impossible to do so (unless you can similarly show an
> > inconsistency in Euclidean geometry and also real analysis). <shrug>
>
> > Making impossible assumptions, such as rigid rivet and wall, show an
> > inconsistency IN THE GEDANKEN, not in SR itself.
>
> > > FOR HOW LONG WILL THE SCIENTIFIC COMMUNITY CONTINUE TO WORSHIP AN
> > > INCONSISTENT THEORY ABOUT PHYSICAL REALITY?
>
> > No "worship" is involved. UNDERSTANDING is the proper word.
> > Unfortunately, that seems to be beyond you. So STUDY. Or find another hobby.
>
> > Tom Roberts- Hide quoted text -
xxein
> xxeinwrote:
> > Source independency does not confer any other
> > attribute to light except the ability to function apart from the
> > source.
>
> Hmm. That plus the PoR implies that the vacuum speed of light is
> invariant (i.e. has the value c in any inertial frame). It is rather
> silly to separate one statement from a theory and attempt to interpret
> it apart from the rest of the theory....
>
> As for any physical theory (which is a collection of mathematical
> theorems and the interpretations of their symbols), one has many choices
> for the set of equations one takes as postulates. Einstein selected his
> postulates to accord with then-current theoretical expectations and
> prejudices.
>
> Today we can select a rather different set of postulates that completely
> avoids criticisms about "assuming the speed of light is constant":
> 1) the PoR
> 2) pion beams exist
> These are sufficient to derive all of SR, when combined with:
> * the definition of inertial frames
> * Einstein's "hidden postulates"
> - clocks and rulers have no memory
> - space is isotropic and homogeneous
> - time is homogeneous and monotonic
> * knowledge of what a pion is.
> Einstein, of course, had no access to the last of these, nor sufficient
> knowledge of group theory to apply them properly.
>
> Indeed, SR became the first major application of group
> theory in theoretical physics, first as a transformation
> group (Lorentz invariance), and then as angular momentum
> in non-relativistic quantum mechanics (!), and ultimately
> in QED and other QFTs.
>
> Today, with knowledge gained from GR, we can see the limitations of
> inertial frames and the PoR. This relegates SR to being merely a LOCAL
> theory.
>
> Tom Roberts
xxein: So? You said SR is local. You mean local measurement, don't
you? How is GR not anything else when it uses SR as a local
measurement of a change?
Geez, Tom, your stricture of/to the physic is pitiful.
Relativity and Q theories cannot co-exist as you attempt to decribe
them. The measurement becomes subjective to the conditions in
relativity and yet a Q theory has no relativity to measure or
consider.
Would you like to explain this?
PD
> On May 15, 4:52 pm, PD <TheDraperFam...@gmail.com> wrote:
>
>
>
> > On May 15, 8:23 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>
> > > Mike wrote:
> > > > A) Nothing impossible is assumes.
>
> > > Yes, a perfectly rigid rivet and wall are assumed, which are impossible
> > > in SR, and TO APPLY SR one cannot assume things that are IMPOSSIBLE IN
> > > SR. Without those assumptions, the bug is always crushed as rivet and
> > > wall disintegrate on impact. <shrug>
>
> > And in fact, perfectly rigid objects are impossible not only in SR but
> > also among the other laws of physics. (And in fact, a moment's thought
> > will tell you that SR is little more than the invocation of the laws
> > of physics and the principle of relativity.) This is true not just as
> > a practical matter but even in principle. There are several puzzles in
> > relativity that explicitly remind the student that rigidity is
> > inherently anathema in the real world.
>
> You sound full of tears...
>
> What real world? This is a mathematical inconsistency illustrated by
> an example.
Which goes to show you can show anything you want with mathematics as
long as it doesn't involve objects that are constrained by the laws of
physics -- that is, as long as you're talking about unphysical things.
>
> Don't cry now. You want to go back and change all of mechanics?
>
> T+You do not seem to say the same things about falling elevators and
> the "feel" that free fall = acceleration.
That's right. There is no implicit assumption in falling objects that
inherently includes unphysical objects.
>
> When it suits you, you get as anthropocentri as you want, mixing
> physics with feelings and perception.
>
> This attitude will gets you nowhere.
>
> Prety soon some Chineese or Indian who is not threatened by the
> establishement with losing his job will falsify you experimentally.
Then we'd all win, with something exciting.
Notice how sure you are of your position, even before having any
evidence in hand. That is the difference.
Pentcho Valev
sci.physics.relativity:
Roberts Roberts you feel so good in Einstein zombie world don't you.
Zombies would never consider a very thin "bug" and, accordingly, a
lower, non-disintegrating speed. Yet some time ago an exception
occurred: a zombie calling himself "Dono" sudenly discovered that,
although Divine Albert's Divine theory predicts that a 80m long pole
can gloriously be trapped inside a 40m long barn, there is still
something awkward about this prediction:
http://www.math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html
"These are the props. You own a barn, 40m long, with automatic doors
at either end, that can be opened and closed simultaneously by a
switch. You also have a pole, 80m long, which of course won't fit in
the barn....So, as the pole passes through the barn, there is an
instant when it is completely within the barn. At that instant, you
close both doors simultaneously, with your switch. Of course, you open
them again pretty quickly, but at least momentarily you had the
contracted pole shut up in your barn."
Who cares about zombie Dono's discovery now? Nobody. Even zombie Dono
himself has forgotten it and is fighting even more fiercely against
those who claim that Divine Albert's Divine Theory is an
inconsistency. Nice place Einstein zombie world isn't it Roberts
Roberts.
Pentcho Valev
pva...@yahoo.com
Simple Simon
> Simple Simon wrote:
> > I fail to understand the need to refer to clocks and rulers in the
theory.
>
> To be useful, a physical theory must relate to measurements. Clocks and
> rulers are what we use to measure time intervals and distances.
>
>
> > That is, the theory and relationships between relative temporal and
spatial
> > displacements exists even if we didn't exist and weren't here to measure
> > them. The theory of their operation might be necessary to run
experiments in
> > order to (in)validate a theory, but they are merely artifacts. No?
>
> Certainly the relationships hold whether they are measured or not, and
> whether humans observe them or not. But it's not clear how to define
> space or time intervals without rulers and clocks.
Can't the whole thing be done using coordinates?
>
>
> Tom Roberts
Mike
The evidence has been presented to you many times but you dismiss it.
You label PoR and c physical principles but when presented with an
inconsistency you try to find ways to declare it non-physical.
The bug-rivet paradox illustrates a LOGICAL CONTRADICTION arising from
SR. Two contradictory propositions are derived mathematically from the
same theory from logical premises.
The deduction is sound and valid.
Excuses are just excuses.
Mike
> > > - Show quoted text -- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
papa...@gmail.com
There is no paradox. "The correct solution works like this:
In the rivet frame, the end of the rivet reaches the bottom of the
well and crushes the bug because of the shortened depth of the well.
( The end hits the bottom of the well before the head reaches the top
of the well.)
In the bug frame, the head of the rivet hits the top of the well while
the end of the rivet is still 3/4cm from the bottom of the well. But
because of the speed of light restrictions, the fastest the
information that the rivet head has stopped can reach the end of the
rivet is at c. Since we are dealing with the bug's frame, this means c
with respect to the bug. The end of the rivet continues to move (at .
866c) until it gets this information. The time it takes for this
information to catch up with the moving end is equal to:
t=\frac{0.25cm}{(c-0.866c)}
And the distance the end of the rivet travels in this time is
t=0.866c\frac{0.25cm}{(c-0.866c)}
This works out to about 1.6 cm.
Thus the end of the rivet reaches the bottom of the well before it
ever finds out that the head of the rivet has stopped and crushes the
bug."
Miguel Rios
Mike
Paparios, In SR, c is constant, it does not depend on reference frame
speed. So t = 0.25cm/c, unfortunately for the bug and you.
What you wrote applies in Gallilean relativity.
>
> And the distance the end of the rivet travels in this time is
>
> t=0.866c\frac{0.25cm}{(c-0.866c)}
>
> This works out to about 1.6 cm.
>
> Thus the end of the rivet reaches the bottom of the well before it
> ever finds out that the head of the rivet has stopped and crushes the
> bug."
Your analysis is wrong. No cigar for you.
Mike
>
> Miguel Rios- Hide quoted text -
Tom Roberts
> There is no paradox. "The correct solution works like this:
No, it doesn't. You made a very basic mistake. One that's EASY to make
because of the VERY bad gedanken and the impossible assumptions it
makes, including the fact that the rivet does not stop instantaneously
in ANY inertial frame.
> In the rivet frame, the end of the rivet reaches the bottom of the
> well and crushes the bug because of the shortened depth of the well.
While the rivet is stopping, THERE IS NO "RIVET FRAME" in which the
rivet is at rest.
> ( The end hits the bottom of the well before the head reaches the top
> of the well.)
This simply is not true, as long as one assumes the rivet is perfectly
rigid.
> [...]
> This works out to about 1.6 cm.
That's the inconsistency in your analysis -- the rivet is now at rest in
the bug frame, but you have it being 1.6 cm long, which is wrong.
> Thus the end of the rivet reaches the bottom of the well before it
> ever finds out that the head of the rivet has stopped and crushes the
> bug."
This is not true.
Considered in the bug frame, the (short) rivet's head hits the wall and
stops. The part of the rivet body immediately ahead of the head stops,
and in the process of doing so, expands (in this frame). then the part
of the rivet immediately ahead of that stops and expands (in this
frame), etc. all the way to the end of the rivet. It should be clear
that in the bug frame the expansion of the rivet while it is stopping is
MONOTONIC, and so the rivet never crushes the bug. Note this has nothing
to do with elastic deformation of the rivet, it's just that different
regions of the rivet stop in the bug frame at different times in the bug
frame.
In the INITIAL rivet frame [#], one finds that the end of the rivet
stops before the head. This seeming violation of causality is due to the
impossible assumption of perfect rigidity. This is a simple consequence
of the previous discussion in the bug frame, transformed to the rivet frame.
[#] I of course mean the inertial frame of the rivet
before it begins stopping, and REMAINING in this frame
until after the rivet is stopped. This is NOT the "rest
frame of the rivet" while it is stopping.
As I said earlier, assuming perfect rigidity is incompatible with SR. So
the whole gedanken is ridiculous, because it inherently violates SR, and
also because this rivet has a kinetic energy comparable to a small
atomic bomb (!), and cannot possibly stop. In addition, the fact that
there _IS_ no "rivet frame" makes the analysis not elementary.
This does not illustrate any problem with SR. It merely illustrates the
fact that this is a VERY BAD gedanken.
Tom Roberts
papa...@gmail.com
I totally agree with you in that this gedanken is bad. It is true that
you can't stop a rivet when it hits a wall, without destroying it and
generating a big big crater on the wall. However, what I see in the
explanation of the Hyperphysics page is that they are considering both
the rivet and the wall just before they make physical contact and so,
in this manner, they do not need to take into account the rigidity
problem and can apply Lorentz relations. Of course, just a little tiny
bit of time later the rivet hits the wall and the atomic bomb
explodes, so the bug history is really irrelevant in practical terms.
Miguel Rios
Darwin123
> Let us discuss How Einstein come to the conclusion that speed of light
> is constant.
> I believed that he reached that conclusion after Michelson Morley
> experiment. But the fact is that, he postulated it before that
> experiment.
>
> Note: while posting your comments, please stick to the topic.
He came to that conclusion on the assumption that electrical
properties are invariant to velocity. If the speed of light wasn't
constant (i.e., there was an ether wind), then the electrical
properties of circuits and materials would also be affected by the
velocity.
Although this is a conjecture, I think a surprising number of
people find it intuitive. If there was an ether wind, there would be
light would be the limiting velocity of travel anyway. Suppose you are
in a rocket ship moving at 99% of the speed of light. Now suppose the
laws of electricity varies with the speed of the observer. In other
words, put a Galilean transformation on all the electrical properties
in the materials of your body. Puff, your nerve cells stop working.
You drop dead. The ether wind killed you.
I am not sure where this came from, but I read somewhere the
following thought experiment supposedly formulated by Einstein.
Suppose you are looking in a mirror in a rocket that is moving as fast
as the speed of light in the direction defined by an arrow from you to
the mirror. If there is an ether wind, you would never see your own
reflection.
The problems mostly had to do with the ether theory. While the
ether theory explained some optical phenomena, it couldn't be extended
to other manifestations of electricity and magnetism.
The point is that if there is no special relativity, and there is
an ether wind, all the electromagnetic properties have to have a term
that varies with the ether wind. The MM experiment is one you know
about. However, the same logic applies to all the optical properties.
This includes reflectivity (consider that mirror) and refraction. Not
only that, it includes all the electrical properties. The law of
capacitances also has to have an ether wind corrections. All the
magnetic properties have to have an ether wind correction.
It wasn't just the MM experiment. There were experiments
involving the torque on an electrical coil that indicated the absense
of ether wind. Every single electromagnetic property should have shown
some evidence of ether wind.
Not only that, astronomical observation should have shown
evidence of ether wind. I mean, the sunspots (which are magnetic)
should have been moved around by the ether wind caused by the velocity
of the sun through the galaxy.
Just about everything should have been influenced by an ether
wind. But no experiment seemed to show the existence of an ether
wind.
There were other problems with the ether theory. H. A. Lorentz
mentioned one. You can not derive the force law between a charged
particle, an electric field, and a magnetic field using the concept of
ether (Theory of Electrons). Einstein was more specific about it. The
force law for the interaction between electric charges, electric
fields, and magnetic fields was observer dependent. The force wasn't
observer dependent, but the ratio between electric and magnetic fields
changed with velocity. Why would the field change but not the force?
Explain that with ether wind.
A scientist called Lorenz came up with still another objection
to ether theory. How come light in a vacuum has two transverse
polarizations and only one longitudinal polarization? There was no way
to explain this with ether theory. The same goes for radio waves,
which are even more clearly a manifestation of electricity and
magnetism. If there was an ether wind, it could mix up the
polarizations so the polarization vectors were not orthogonal. Again,
ether failed.
I propose that what inspired Einstein was more of the general
failing of ether theory, not the specific failure of the MM experiment
to find ether wind. The MM experiment probably was in the back of his
mind. The MM experiment would have made his articles even stronger if
he had remembered it. However, the total absence of ether wind in ANY
experiment or observation probably bothered him more. It was a
negative result. The ether wind never turned up in any earthbound
experiment or astronomical observation. Other people were bothered by
it absence, too.
I am not trying to take any credit from Lorentz or Lorenz.
However, Einstein came up with the most general theory to explain why
the ether wind NEVER seemed to show itself anywhere.
Darwin123
> "Tom Roberts" <tjroberts...@sbcglobal.net> wrote in message
>
> news:%O7Wj.3373$J16....@newssvr23.news.prodigy.net...
> I fail to understand the need to refer to clocks and rulers in the theory.
There is a general name for such a theory. It is called a
symmetry. A symmetry is a repetitious pattern that is embedded in the
physical system being studied. It is a redundancy in certain physical
properties. If the measuring instruments have the same symmetry as the
system being studied, one can use that redundancy to simplify any
description of the experiment.
I have worked with crystals, so I know symmetries. If a crystal
has a six-fold axis, I only have to do measurements on one of the six
sections. The other measurements tend to repeat. If I know before hand
that the crystal is six-fold, I can make a measurement over all six
sections and then average the six measurements for greater accuracy.
The redundancy of the six sections helps me simplify the problem.
Although I could do the measurements and then assume six fold
symmetry, what is practical is to do some experiments early on,
recognize the symmetry early and then do other measurements that use
the six-fold symmetry.
In the case of relativity, Einstein assumed that all electrical
properties in a vacuum was invariant to the velocity of the observer
(not to the acceleration, but that is another study). Since all
observers see the same speed of light, measurement by any one observer
is redundant. On the assumption that the speed of light is the same
for all inertial observers, a surprising amount of simplification can
be obtained.
Including the clock and ruler is simply saying that all forces,
including the forces in the clocks and rulers, are Lorentz invariant.
This is a symmetry.
Lorentz derived the special relativity symmetry for a particular
case. He did not prove it in general, he proved it for a specific case
and then said that the symmetry was useful. Einstein flat out started
with the symmetry. Lorentz thought this little step was brilliant.
Maybe, but I personally like Lorentz's approach better. It was more
complicated, but more satisfying for me.
Mike
>
> - Show quoted text -
Before the bomb explodes, the data has been sentout and read as
follows:
P: The bug is dead
~P: The bug is not dead
This rigidity think is a =n outrageous effort from the part of Roberts
to dismiss what is obvious a simple description of the mathematical
inconcistencies in SR.
SR people claim it is as consistent as Euclidean geometry. This is
false, because SR is NOT only geometry. Yes, the geometrical part is
consistent.
BUT when you add the physical part, which is constancy of speed of
light, you get an inconsistent theory.
But you seem not to understand SR. Otherwise you would have not made
such an elementary mistake and use Galilean Relativity.
Mike
PD
No, both observers agree the bug is dead. In the rivet frame, this is
clear. In the bug frame, this observer notes that the foot of the
rivet continues moving after the head of the rivet comes to a stop.
This is identical to the pole and barn paradox where the barn doors
are actually closed. A lot of authors don't like to close the barn
doors because it introduces dynamics into what's going on and it isn't
as clean in terms of reference frames, but it can be handled just as
well.
papa...@gmail.com
Well...this thing has been discussed several times before, for
instance see:
http://www.physicsbanter.com/theory-relativity/32864-seeming-sr-paradox-unresolved.html
where S. Carlip takes a similar approach to the one I put in my
previous post which, by the way, I took from (notice the " before and
after the text in my post?):
http://www.physicsforums.com/archive/index.php/t-57063.html
So either you take the position of considering the rivet and wall as
indestructible (remember that in that case when the rivet or the wall
stops moving, contraction should disappear, so Lorentz equations are
not longer valid), or you consider that for a very brief instant of
time the rivet is still moving inertially and has entered the hole in
the wall and Lorentz equations are valid for a nanosecond. That means
nobody agrees on what happens (not Carlip nor Roberts nor you) and for
that reason it is a bad example of a paradox. The only thing that it
is sure is that an object like a rivet (let us say with a mass of
50grams) moving at 0.9c has a lot of kinetic energy to disipate, and
if, as the description of the "paradox" states, the rivet stops when
its head hits the wall, that energy has to go somewhere (usually that
would mean heat and shock waves).
Miguel Rios
Miguel Rios
Pentcho Valev
sci.physics.relativity:
No the approach is entirely different: Steve Carlip introduces a red
herring by asking an irrelevant question:
Steve Carlip: "It's really the same as the barn-and-pole paradox, in
the variant
in which the person at rest wit respect to the barn waits until the
pole is inside and closes the door. Here's a hint: in the bug's frame
of reference, what happens to the tip of the rivet when the head hits
the wall? Remember, the information that the head has hit the wall
can't travel down the rivet faster than light."
Steve Carlip is a silly Einsteinian but still he is much cleverer than
you.
Pentcho Valev
pva...@yahoo.com
Pentcho Valev
sci.physics.relativity:
A very bad gedanken Roberts Roberts, an awful gedanken indeed:
http://hyperphysics.phy-astr.gsu.edu/Hbase/Relativ/bugrivet.html
Roberts Roberts your atomic bomb argument is so desperate.... You are
not so silly Roberts Roberts you surely have noticed that the bug is
unimportant: "squashing the bug" can be replaced by "contact betwen
the end of the rivet and the bottom of the hole" and then, not so
silly Roberts Roberts, if the proper length of the rivet is very close
to the proper length of the hole, the speed could be much lower than
0.9c.
By the way Roberts Roberts your cleverer brothers in Einstein criminal
cult do not care much about your atomic bomb argument - see:
http://www.people.fas.harvard.edu/~djmorin/book.html
Chapter 11, p. 42, Problem 11.7: "Seeing behind the stick"
The stick hits the wall Roberts Roberts, stops and....nothing. No
atomic explosion.
Pentcho Valev
pva...@yahoo.com
mitch.nico...@gmail.com
> On May 15, 9:23 am, Tom Roberts <tjroberts...@sbcglobal.net> wrote:
>
> > Mike wrote:
> > > A) Nothing impossible is assumes.
>
> > Yes, a perfectly rigid rivet and wall are assumed, which are impossible
> > in SR, and TO APPLY SR one cannot assume things that are IMPOSSIBLE IN
> > SR. Without those assumptions, the bug is always crushed as rivet and
> > wall disintegrate on impact. <shrug>
>
>
>
>
> > > Istead of a bug you can have a switch to turn on a light.
>
> > Then the switch is destroyed, perhaps making contact, perhaps not.
>
> > > B) The river is at rest
> > > in it's own frame. It moves uniformly towards the bug.
>
> > Not once its rigid head hits the rigid wall and forces the rivet head to
> > stop instantaneously, while the body of the RIGID rivet continues moving
> > for a (very) short time. Rigidity normally applies in the rivet rest
> > frame, but during the interval just after the head stops at the wall,
> > the ENTIRE rivet is not at rest in any inertial frame. THAT'S one reason
> > why this is such a bad gedanken (assuming rigidity is another such reason).
>
>
> > > You have no desire to discuss it because even hypephysics falsifies
> > > your statement.
>
> > As I said, I have no desire to discuss it as it makes such unreasonable
> > assumptions. Ones that are INCONSISTENT with SR. <shrug>
>
>
> > > SR IS AN INCONSISTENT PHYSICAL THEORY.
>
> > You need to show this. Nobody has ever done so, and it has been proved
> > that it is impossible to do so (unless you can similarly show an
> > inconsistency in Euclidean geometry and also real analysis). <shrug>
>
> > Making impossible assumptions, such as rigid rivet and wall, show an
> > inconsistency IN THE GEDANKEN, not in SR itself.
>
>
> > > FOR HOW LONG WILL THE SCIENTIFIC COMMUNITY CONTINUE TO WORSHIP AN
> > > INCONSISTENT THEORY ABOUT PHYSICAL REALITY?
>
> > No "worship" is involved. UNDERSTANDING is the proper word.
> > Unfortunately, that seems to be beyond you. So STUDY. Or find another hobby.
>
> in a remarkably hillarious way.
>
> Get serious, drop either the PoR or the constancy of c or both. Be
> brave, or find another hobby.
>
> and while we are on that, don't ever tell anyone on a rollocoster that
> force they FEEL is an artifact of reference frame.
>
> IT THE CENTRIFUGAL FORCE. More tahn real, regardless of whether or not
> some succeeded to take down the NASA page declaring so.
>
> THERE IS NOTHING FICTICIOUS ABOUT THE BULDGE OF THE EARTH AT THE
> EQUATOR.
>
> hahahahahahahaha
>
> sci.physcis.relativity is a lot of fun.
>
> Mike
>
>
>
>
>
> > Tom Roberts- Hide quoted text -
>
> - Show quoted text -
Traveling behind light.
BradGuth
limited to something less than 300,000 km/s.
Get past the local ISM of dark matter and the photon race is on.
Possibly 1,000,000 km/s.
. - Brad Guth
Pentcho Valev wrote:
> On May 13, 5:19�am, Tom Roberts <tjroberts...@sbcglobal.net> wrote in
> sci.physics.rlativity:
> Always devising new camouflage Roberts Roberts? Why do Einsteinians
> need "a rather different set of postulates that completely avoids
> criticisms about "assuming the speed of light is constant"? Are they
> afraid of something? Old camouflage:
>
> http://groups.google.com/group/sci.physics.relativity/browse_frm/thread/1cb971595bf0fe4?
>
> If I were you Roberts Roberts, I would immediately adopt the
> "different set of postulates" that Brother Jean Eisenstaedt offers:
>
> http://ustl1.univ-lille1.fr/culture/publication/lna/detail/lna40/pgs/4_5.pdf
> Jean Eisenstaedt: "Il n'y a alors aucune raison th�orique � ce que la
> vitesse de la lumi�re ne d�pende pas de la vitesse de sa source ainsi
> que de celle de l'observateur terrestre ; plus clairement encore, il
> n'y a pas de raison, dans le cadre de la logique des Principia de
> Newton, pour que la lumi�re se comporte autrement - quant � sa
> trajectoire - qu'une particule mat�rielle. Il n'y a pas non plus de
> raison pour que la lumi�re ne soit pas sensible � la gravitation.
> Bref, pourquoi ne pas appliquer � la lumi�re toute la th�orie
> newtonienne ? C'est en fait ce que font plusieurs astronomes,
> opticiens, philosophes de la nature � la fin du XVIII�me si�cle. Les
> r�sultats sont �tonnants... et aujourd'hui nouveaux."
> IN ENGLISH: "Therefore there is no theoretical reason why the speed of
> light should not depend on the speed of the source and the speed of
> the terrestrial observer as well; even more clearly, there is no
> reason, in the framework of the logic of Newton's Principia, why light
> should behave, as far as its trajectory is concerned, differently from
> a material particle. Neither is there any reason why light should not
> be sensible to gravitation. Briefly, why don't we apply the whole
> Newtonian theory to light? In fact, that is what many astronomers,
> opticians, philosophers of nature did by the end of 18th century. The
> results are surprising....and new nowadays."
>
> Pentcho Valev
> pva...@yahoo.com
BradGuth
> "In the end the Party would announce that two and two made five, and
> you would have to believe it. It was inevitable that they should make
> that claim sooner or later: the logic of their position demanded it.
> Not merely the validity of experience, but the very existence of
> external reality, was tacitly denied by their philosophy. The heresy
> of heresies was common sense. And what was terrifying was not that
> they would kill you for thinking otherwise, but that they might be
> right. For, after all, how do we know that two and two make four? Or
> that the force of gravity works? Or that the past is unchangeable? If
> both the past and the external world exist only in the mind, and if
> the mind itself is controllable what then?"
>
> Pentcho Valev
> pva...@yahoo.com
Orwell wasn't off by all that much. Mike however seems in love with
you.
. - BG