Bill Hobba writes

"John Kennaugh" wrote in message
o.uk...
Bill Hobba writes

Axiom (2) Constancy of speed of light

No. Why describe it Axiomatic? It was the result of reasoning from
observation. That reasoning might, or might not, have been flawed.

That suic a constant exists follows form hte POR alone.

Prove it!

The paper I linked to did.

No it doesn't.
Maybe you should ask yourself why the paper was written, why you think
it is important and why you (and several others) have brought it to my
attention. Essentially it goes like this. Light experiments were
interpreted as indicating that light is a propagated wave. This led to
belief in the ether and that led to belief in source independence.
Einstein incorporated source independence into his second postulate.
Minkowski found you could put Einstein's equations in the form of a
diagram and mix time with linear dimensions by multiplying it by c which
according to the second postulate gives you a unique value for a given t
because c is constant in the FoR of any measurement. This in turn
developed into spacetime geometry.

Now the problem is that a theory should be traceable. If you trace the
logical steps to relativity you find that it is all dependent on there
being an ether. Once that is realised you have 3 choices. You can
reinstate the ether - in which case SR is simply the maths of LET. You
can reject SR on the grounds that you have rejected its basis the ether
or you can try and find an alternative rationale on which to base your
belief. Even if you succeed the implication is that science has, by some
incredible good fortune come across the right theory for all the wrong
reasons. If it was a fairly obvious, intuitive theory one might believe
that to be possible but it isn't. As I said to Bilge if relativity is
correct it can only be so, either because the ether does exist or
because of divine inspiration.

Now let us look at your http://arxiv.org/abs/physics/0110076.

"Status of the invariance of the speed of light was reduced from a
foundation of the Special Theory of Relativity to just a property which
allows to determine a value of the physical constant [3]".

[3] Schroder U.E. Special Relativity

In other words in respect of the relevant bit he quotes someone else so
I still don't know the argument.

Did you read it or is calculus beyond you?

You obviously didn't.

Then there is the little statement:

"In this paper the following convention is used for
representation of co-ordinates: xo = t ......"

What he has done has he not has normalised c to be 1 and xo = ct. Even
if c is normalised you should still include it in all expressions to
keep dimensions correct. xo = ct is assuming the second postulate. If
you take ballistic theory then the speed of light is only c to an
observer in the same FoR as the source.



For
another proof based on group theory see an ancient post by Tom Roberts

http://groups.google.com/groups?q=A+...on+of+Special+
Relativity&hl=en&lr=&group=sci.physics.relativity &c2coff=1&selm=54jfst%2
4glp%40ssbunews.ih.lucent.com&rnum=1

I haven't time at the moment to look at this. I have saved it for
further study. It seems to assume space-time which as I state above has
the second postulate built in. I hope to study it further but I know it
will not show

"That such a constant exists follows form the POR alone."

For one very simple reason and that while the first postulate follows
from the PoR, the second postulate, the one which is a consequence of
believing in the ether, is actually an exception to the PoR. If the
speed of light acts in accordance with the PoR it is c relative to the
source, adds to the source, is not source independent.

both http://arxiv.org/abs/physics/0110076 and what Tom Roberts writes
must make an assumption which is the equivalent of the second postulate
otherwise they would end up with Galilao-Newtonian Transforms rather
than Lorentz's.


--
John Kennaugh
to email convert the number from hex to decimal

John Kennaugh:

For one very simple reason and that while the first postulate follows
from the PoR, the second postulate, the one which is a consequence of
believing in the ether, is actually an exception to the PoR. If the
speed of light acts in accordance with the PoR it is c relative to the
source, adds to the source, is not source independent.

both http://arxiv.org/abs/physics/0110076 and what Tom Roberts writes
must make an assumption which is the equivalent of the second postulate
otherwise they would end up with Galilao-Newtonian Transforms rather
than Lorentz's.

The galilean transforms are simply a limiting case of the lorentz
transforms, in which c-\infty. The underlying affine space is the
same. Now, for a more pertinent question, there are several different
forms the galilean group could take. In particular, the form used
in classical physics contains an additional conserved quantity due
to galilean boost symmetry. What is it and why does that suggest a
finite value for `c', by virtue of that quantity not being conserved?

"John Kennaugh" wrote in message
.uk...
Bill Hobba writes

"John Kennaugh" wrote in message
o.uk...
Bill Hobba writes

Axiom (2) Constancy of speed of light

No. Why describe it Axiomatic? It was the result of reasoning from
observation. That reasoning might, or might not, have been flawed.

That suic a constant exists follows form hte POR alone.

Prove it!

The paper I linked to did.

No it doesn't.
Maybe you should ask yourself why the paper was written, why you think
it is important and why you (and several others) have brought it to my
attention.

I stated regarding an invarient speed existing in all inertial frames:

'That suic a constant exists follows form hte POR alone.'

You responded:

'Prove it!'

That is exactly what the papers I linked to did eg in Tom Roberts paper he
stated and proved:

'Many criticisms of Special Relativity center on the "assumption" that the
speed of light is constant in all reference frames. The derivation given
here does not make that assumption; the existence of a universal speed (c)
is a natural consequence of the Postulates forming the basis of the
derivation.'

The other paper said:

'Status of the invariance of the speed of light was reduced from a
foundation of the Special Theory of Relativity to just a property which
allows to determine a value of the physical constant.'

The fact you seem incapable of reading and understanding English indicates
understanding relativity is probably beyond you.

Essentially it goes like this. Light experiments were
interpreted as indicating that light is a propagated wave. This led to
belief in the ether and that led to belief in source independence.
Einstein incorporated source independence into his second postulate.
Minkowski found you could put Einstein's equations in the form of a
diagram and mix time with linear dimensions by multiplying it by c which
according to the second postulate gives you a unique value for a given t
because c is constant in the FoR of any measurement. This in turn
developed into spacetime geometry.

And other researches showed this stuff about light is irrelevant.


Now the problem is that a theory should be traceable. If you trace the
logical steps to relativity you find that it is all dependent on there
being an ether.

That is simply not true.

Once that is realised you have 3 choices.

You have another choice - realize you are simply incapable of understanding
relativity or even probably simple English.

You can
reinstate the ether - in which case SR is simply the maths of LET. You
can reject SR on the grounds that you have rejected its basis the ether
or you can try and find an alternative rationale on which to base your
belief. Even if you succeed the implication is that science has, by some
incredible good fortune come across the right theory for all the wrong
reasons. If it was a fairly obvious, intuitive theory one might believe
that to be possible but it isn't. As I said to Bilge if relativity is
correct it can only be so, either because the ether does exist or
because of divine inspiration.

Now let us look at your http://arxiv.org/abs/physics/0110076.

"Status of the invariance of the speed of light was reduced from a
foundation of the Special Theory of Relativity to just a property which
allows to determine a value of the physical constant [3]".

[3] Schroder U.E. Special Relativity

In other words in respect of the relevant bit he quotes someone else so
I still don't know the argument.

That is because you obviously are unable to think.


Did you read it or is calculus beyond you?

You obviously didn't.

Yea right.


Then there is the little statement:

"In this paper the following convention is used for
representation of co-ordinates: xo = t ......"

What he has done has he not has normalised c to be 1 and xo = ct. Even
if c is normalised you should still include it in all expressions to
keep dimensions correct. xo = ct is assuming the second postulate. If
you take ballistic theory then the speed of light is only c to an
observer in the same FoR as the source.

What the paper did was:

'We have found the form of transformation functions between two frames in
the standard configuration. The only remaining unknown is the value of the
universal
constant u. From the transformation functions we can make a number of
conclusions, for example about possibility of time dilation. Then we could
use time dilation experiments (involving decay of stationery and moving
mesons) to measure the value of u. Another (but not the only) way to find a
value of u is by deriving velocity addition formula and observing that if
c^2 = -u and an object moves with speed c in one inertial frame, then it
moves with the same speed in all others. This would enable us to identify c
as the speed of light in vacuum. But I stress once again that other
experiments could be used to find the value of the constant.'

The fact you wish to doubt the above indicates either you can not understand
simple English or are incapable of the most basic of reasoning - probably
both.

Bill




For
another proof based on group theory see an ancient post by Tom Roberts

http://groups.google.com/groups?q=A+...on+of+Special+
Relativity&hl=en&lr=&group=sci.physics.relativity &c2coff=1&selm=54jfst%2
4glp%40ssbunews.ih.lucent.com&rnum=1

I haven't time at the moment to look at this. I have saved it for
further study. It seems to assume space-time which as I state above has
the second postulate built in. I hope to study it further but I know it
will not show

"That such a constant exists follows form the POR alone."

For one very simple reason and that while the first postulate follows
from the PoR, the second postulate, the one which is a consequence of
believing in the ether, is actually an exception to the PoR. If the
speed of light acts in accordance with the PoR it is c relative to the
source, adds to the source, is not source independent.

both http://arxiv.org/abs/physics/0110076 and what Tom Roberts writes
must make an assumption which is the equivalent of the second postulate
otherwise they would end up with Galilao-Newtonian Transforms rather
than Lorentz's.


--
John Kennaugh
to email convert the number from hex to decimal

Androcles wrote:

Kolker cannot read:
"light is always propagated in empty space with a definite velocity c
which is independent of the state of motion of the emitting body"
Reference :

It is implicit in the mathematics. Light has a definite speed in vaccuo
when measured in inertial frames. The relative motion of the observer or
the light source does does matter. Measurement in vacuou will always
produce the same number.

Bob Kolker

(Bilge) wrote in message ...
John Kennaugh:
robert j. kolker writes


John Kennaugh wrote:

OK lets analyse it. Newton assumed that all speed was relative. The
PoR implies that all speed is relative. If all speed is relative then
the speed of light adds to that of the source.

Only if you assume velocities add.

They do in case you hadn't noticed. Light was made an exception because
it was assumed to travel in the ether and have a speed constant w.r.t
the ether.

Light was postulated to propagate at `c', because (1) maxwell's
equations were believed to be correct, (2) einstein's goal in that
paper was to explain maxwell's equations as a consequence of geometry.

(which he did after Minkowski's 1908 paper on spacetime)

and (3) to accept the existence of a mechanical ether whose rest frame
is the embodiment of a preferred inertial frame would be to undermine
the lack of a need for one either empirically or theoretically in
Newton's theory of mechanics. To claim that such an ether was needed
for charged mass particles but not for neutral mass particles seemed
to Einstein to be dis-harmonious, and changed the concept of (and
fundamental role of) inertiality in physics:

H. A. Lorentz even discovered the "Lorentz transformation,"
later called after him, though without recognizing its group
character. To him Maxwell's equations in empty space held only
for a particular coordinate system distinguished from all other
coordinate systems by its state of rest. This was a truly
paradoxical situation because the theory seemed to RESTRICT
THE INERTIAL SYSTEM more strongly than did classical mechanics.
This circumstance, which from the empirical point of view
appeared completely unmotivated, was bound to lead to the
theory of special relativity.
---- Einstein in: H. A. Lorentz, Creator and Personality,
Ideas and Opinions, p. 75 (emphasis mine).

What was the restriction that bothered Einstein so much? Only that all
inertial frames would no longer be considered as equivalent for the
invention of the laws of physics, which would be a direct violation of
the PoR. Technically, in LET Maxwell's laws only hold in the rest
frame on the ether (that preferred inertial frame of reference where
clocks and measuring rod behave "normally").

(4) ether theories violated Einstein's sense of minimality, or
simplicity. If he could invent a theory that didn't need a preferred
inertial frame, then that would be one less axiom in the system. Of
course, the reasons for simplicity are formal and suit
instrumentalists, but do not seem to suit realists.

The group property that Einstein mentioned refers to the use of form
invariance (covariance) of the equations used to state physical laws.
It is used heuristically and is a weaker form of the PoR, though it is
much more readily used for equation invention. The local laws of
physics are Lorentz covariant regardless of the nature of the forces
involved. From a strictly formal point of view, this principled
heuristic is vastely superior for theory invention than is the
constructive approach of LET. History has decided that unequivocally
long ago.

Patrick

"robert j. kolker" wrote in message
...
:
:
: Androcles wrote:
:
: Kolker cannot read:
: "light is always propagated in empty space with a definite
velocity c
: which is independent of the state of motion of the emitting body"
: Reference :


You snip the reference? LOL.

: It is implicit in the mathematics. Light has a definite speed in
vaccuo
: when measured in inertial frames. The relative motion of the
observer or
: the light source does does matter. Measurement in vacuou will always
: produce the same number.
:
: Bob Kolker

Anyone that ever measured the speed of light measured it
with respect to the source. And yes, I agree, it does does matter.

Androcles.

"John Kennaugh" wrote in message
.uk...
Bill Hobba writes

"John Kennaugh" wrote in message
o.uk...
Bill Hobba writes

[....]

The other paper said:

'Status of the invariance of the speed of light was reduced from a
foundation of the Special Theory of Relativity to just a property
which
allows to determine a value of the physical constant.'

And that simplistic proof-by-assertion is incorrect.

The papers demonstrate otherwise.

No it doesn't it quotes a reference. That reference may or may not
demonstrate otherwise but I haven't seen it. Have you?

John as pointed out in another post it is obvious you did not read the
paper. Anyone that does will see it does exactly what I claim.

OK I have now managed to take a look at Tom Robert's piece. Start with
Einstein:

"... the same laws of electrodynamics and optics will be valid for all
frames of reference for which the equations of mechanics hold good. We
will raise this conjecture (the purport of which will hereafter be
called the 'Principle of Relativity') to the status of a postulate, and
also introduce another postulate, which is only apparently
irreconcilable with the former, namely, that light is always propagated
in empty space with a definite velocity c which is independent of the
state of motion of the emitting body."

The way he did reconcile the second postulate was by assuming that time
was not universal (formally an axiom) nor length but they are dependent
upon relative velocity.

Hey John are you listening? Hello Hello anyone there? Forget Einstein's
paper - the purpose of Toms post was to demonstrate what was laid out in its
introduction and Bilge, myself and others have been trying to tell you for
ages - the speed of light thing is not the basis of SR. Understand it first
then try to link it to what Einstein says. As Toms paper says:

'Many criticisms of Special Relativity center on the "assumption" that the
speed of light is constant in all reference frames. The derivation given
here does not make that assumption; the existence of a universal speed (c)
is a natural consequence of the Postulates forming the basis of the
derivation. General symmetry properties of space-time are sufficient to
determine the equations of the Lorentz Transformation [to within a
topological choice - see below]. The bottom line is that it is IMPOSSIBLE to
formulate an alternative to Special Relativity, while obeying the observed
symmetries of space-time and agreeing with the experimental evidence [see
below about the limitations of the symmetry postulates used in this
derivation].'

100 years down the line we are perhaps over
familiar with that idea and are so used to applying transforms that we
have forgotten how revolutionary they were and how specific they are to
relativity. Clearly if you start with Lorentz transforms and work
backwards you can get back to the idea that c is a constant in all
frames. Superficially that is not what Tom Roberts does.

He starts by assuming that transforms are everyday mathematical
operators with an existence outside of relativity and proposes a
completely general form:

x' = A(u)*x + D(u)*t + E(u)
t' = B(u)*x + C(u)*t + F(u)

These follow from the calculus and the homogeneity properties of an inertial
frame - the other paper I referenced provides the details although it is
more complex than it needs to be - but it will do for a start.


By making x = 0 t = 0 coincident with x' = 0 t' = 0 it simplifies to:

x' = A(u)*x + D(u)*t
t' = B(u)*x + C(u)*t

At this point he is not saying that time _does_ vary with relative
velocity he has merely allowing for the possibility that it might.

He derives a series of such equations transforming between 3 FoR and
essentially works out a series of relationships which are necessary for
the transforms to be internally consistent. e.g. that if you transform S
to S' you can use the same transforms in reverse and that if you
transform S to S' to S'' to S you again end up back where you started
from. So far so good. Along the way he defines a factor q

q = B(u)/(u*A(u))

He then says "Choosing q0 yields the Lorentz transformation".


Correct - and he demonstrates it does.

If q0 then B cannot be 0 so that is the equivalent of saying "if we
assume that time is dependent upon relative velocity"

Yes that is an implication of B 0. So? Is it not the job of experiment
to determine if that is true ie to determine the value of q?

Which is a
prediction of relativity based upon the second postulate and from which
you can work back and conclude that there must be a speed which is the
same in all FoR and when you find its value it turns out to be c.

Sure


What Tom has done is shown that the set of transforms Einstein derived
were the only set of transforms he could have derived to reconcile the
seemingly irreconcilable. That is in effect saying that Einstein had to
use all the degrees of freedom available.

What he showed is that from the assumptions he detailed - none of which
involved anything to do with light - the Lorentz transformations results up
to a choice of constant. The choice of the value of the constant comes from
experiment and is examined later. Tom also demonstrates the assumptions he
made are not irreconcilable.


Even if you derive dilation equations using a train, a light clock, and
the observer on the embankment you reach that conclusion.

This derivation specifically stays away from that approach - as stated in
the beginning its purpose was to show that the light thing really has
nothing to do with it. You keep wanting to introduce it for you own
purposes. It is not required - forget about it.

With the light
clock vertical, in order for both the observer on the train and the
observer on the embankment to determine the same value for the speed of
light either the clock must be shorter or the time dilated. If you try
it with the light clock shorter you run out of options. Basically you
can make length get shorter in one direction and not in another but you
cannot do that for time and the only way round you can make it all work
is to assume time dilation for the vertical clock, you then have to
assume the same time dilation for the horizontal clock and use length
dilation to reconcile the speed of light for the two observers observing
the horizontal clock.

Where do you get this light rubbish from? As Tom says at the end:

'Identifying the actual topology of space-time can only be done by resorting
to physical observations of phenomena in the real world (i.e. by doing an
experiment). There is a tremendous body of experimental evidence that shows
that the speed of light is independent of the velocities of either the
source or observer (there are also many other, equivalent observations).
This compels us to choose the Lorentz Transformation (Eqns 38-41), and to
identify the arbitrary constant "c" with the speed of light. No other choice
is possible, while satisfying the four Postulates and the experimental
evidence.'

As the other link I gave you says when it reaches a similar point in its
derivaiton (what Tom calls q it calls u).

'We have found the form of transformation functions between two frames in
the standard configuration. The only remaining unknown is the value of the
universal
constant u. From the transformation functions we can make a number of
conclusions, for example about possibility of time dilation. Then we could
use time dilation experiments (involving decay of stationery and moving
mesons) to measure the value of u. Another (but not the only) way to find a
value of u is by deriving velocity addition formula and observing that if u
= 1/c^2 and an object moves with speed c in one inertial frame, then it
moves with the same speed in all others. This would enable us to identify c
as the speed of light in vacuum. But I stress once again that other
experiments could be used to find the value of the constant.'

It is obvious you need to work on your comprehension ability. You obviously
are not reading the papers correctly. Forget what you have read previously
about relativity and approach the papers fresh. After you understand them
then try and connect it with what Einstein says.

Bill


--
John Kennaugh
to email convert the number from hex to decimal

robert j. kolker:


Bilge wrote:

Actually, velocities _do_ add - precisely the way one would expect
the slopes of two lines, with slopes tanh(A) and tanh(B). Tell me
something. If I have two lines in a plane, one with slope,

That is not arithmetic addition. I prefer to refer to compositon by the
tanh rule as composition of velocities. The use of hyperbolic functions
as slopes or velocities is not intuitive.

It is if you make it point to try and understand the geometry in the
same way you understand 3-d euclidean geometry. I used to dislike the
hyperbolic form, but I've come to believe that by stressing the fact
that the derivation of the lorentz boosts and spatial rotations is
the _same_ derivation, it emphasizes the geometric content explicitly.
Oviously, the usual way the transforms are derived and written fails
to make an impression of the geometric nature of special relativity and
gives people the wrong idea that it's essential that `c' be the speed
of light.

It only works in connection with hyperbolic geometry which follows
from the invariance of the Minkowski Interval (a non-positive definite
quadratic form).

Well, those are hyperbolic functions. What do you expect? In general,
the way you add two numbers depends upon the rules of addition you define.

Androcles writes

"robert j. kolker" wrote in message
...
:
:
: John Kennaugh wrote:
:
:
: OK lets analyse it. Newton assumed that all speed was relative.
The PoR
: implies that all speed is relative. If all speed is relative then
the
: speed of light adds to that of the source.
:
: Only if you assume velocities add. Under Lorentz transforms
velocities
: do not add. Who needs aether?
:
: At no point does Einstein assume an aether. He assumes the velocity
of
: light is constant in inertial frames regardless of the motion of the
source.
:
: Bob Kolker

Kolker cannot read:
"light is always propagated in empty space with a definite velocity c
which is independent of the state of motion of the emitting body"
Reference :
http://www.fourmilab.ch/etexts/einstein/specrel/www/
Nowhere in that paper does the term "inertial" appear.

That is perfectly true and the above quote is horribly ambiguous. If
with hindsight we know what he intended to say then his second attempt
is better:

"Any ray of light moves in the ''stationary'' system of co-ordinates
with the determined velocity c, whether the ray be emitted by a
stationary or by a moving body."

The use of the phrase 'stationary system' is perhaps unfortunate in a
theory which is arguing that there is no such thing as absolute motion
and hence no such thing as stationary. However to be fair he has defined
'stationary system' thus:

"Let us take a system of co-ordinates in which the equations of
Newtonian mechanics hold good. In order to render our presentation more
precise and to distinguish this system of co-ordinates verbally from
others which will be introduced hereafter, we call it the ''stationary
system.''"

That surely is a definition of what is called in modern terminology an
'Inertial FoR' is it not. It is certainly justified to find an
alternative phrase to the terribly confusing 'stationary system'. As far
as I can see Bob has quite legitimately substituted a modern term with
the same definition for the unfortunate one Einstein used.


Kolker is making up his own interpretation and doesn't understand that
he is, well... lying, is the only word for it.

OTT.

--
John Kennaugh
to email convert the number from hex to decimal

In message , robert j. kolker
writes


Androcles wrote:

Kolker cannot read:
"light is always propagated in empty space with a definite velocity c
which is independent of the state of motion of the emitting body"
Reference :

It is implicit in the mathematics.

Cart before horse. Einstein's 'assumption' is naturally reflected in the
maths which came from that assumption. You cannot suggest that the maths
justifies the assumption they are based upon. That is circular. That is
of course what Bilge tries to do. It is rather less obvious because the
maths has metamorphosed several times and is several generations down
the line but it is still circular. They attempt to break the circle by
trying to derive the maths from a different starting point because the
original starting point is an embarrassment. If you trace where
Einstein's assumption came from it is a belief that the speed of light
could not be affected by the source because it is constant w.r.t the
ether and of course the ether is something no self respecting relativist
will admit to believing in.

Light has a definite speed in vaccuo when measured in inertial frames.

..... when measured over a fixed distance i.e. with no relative motion
between source and detector. It is rather hard to measure the speed of
light from a moving source.

The relative motion of the observer or the light source does does
matter.

There was no experimental evidence for that when Einstein made his
assumption. The only experimental evidence was that offered by DeSitter
after SR was published and that was discredited in 1965 by Fox.

Measurement in vacuou will always produce the same number.

Again when measured over a fixed distance i.e. with no relative motion
between source and detector.
--
John Kennaugh
to email convert the number from hex to decimal