"greywolf42" wrote in message
news
"Bill Hobba" wrote in message
...

wrote in message
om...
(Bilge) wrote in message
...
:
Dear Mr. Keynon and sirs!

In order to construct the Special theory of relativity (SR),
Einstein
advanced two axiom assumption which be called SR's two postulates
in
which the second one is "the speed of light c in vacuum is
invariant
in all of the inertial reference frames."

The second postulate is unnecessary. It's sufficient to assume the
first and determine `c' from experiment.

No, actually no!

Please see the following ancient post by Tom Roberts:


http://groups.google.com/groups?q=ph...ty&hl=en&lr =

&group=sci.physics.relativity&selm=54jfst%24glp%40 ssbunews.ih.lucent.com&rnu
m=4

And note from the introduction:

'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].'

Unfortunately, that ancient post has been shown to be defective in several
respects. In this old derivation, Tom refers to 'coordinate systems.'
However, since that time, Tom has had to modify his viewpoint to require
'inertial frames.'

There is no incompatibly between an inertial frame and inertial coordinate
system - an inertial coordinate system is simply a (usually Cartesian)
system contained in an inertial frame.

Once Tom requires the Lorentz Transform (which is the
historical basis for the 'general symmetry properties of space-time'),
there's nothing left to do. Tom simply reversed the historical basis of
spacetime. Which is trivial, and meaningless.

So what you are saying is the derivation follows from the assumptions so it
is trivial and meaningless.

Bill



--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

greywolf42 wrote:
"Paul Bramscher" wrote in message
...

greywolf42 wrote:


"Martin Hogbin" wrote in message
...


{snip higher and uncommented levels}


OK, I accept all your notes. However, there aren't any measurements
that have been made in pure vacuum or in inertial frames. So where is
your evidence?

Quite simply, you have made a bald statement-by-assertion: "Light speed
is constant for all observers in an inertial frame in a pure vacuum."
Hence, it is up to you to support this claim. As far as I know, all you
have going for you is Einstein's postulate.

Perhaps many models describe an idealized and abstract set of
circumstances to one degree or another. I'm somewhat astounded how
idealized (non-extistent vaccuum) and how abstract (inertial frames)
this one happens to be.

This makes assumptions required for relativity very powerful (indeed,
non-falsifiable by empirical/experimental evidence), since conditions
sufficient to disprove this assumption are either non-existent or
arbitrary.


I wouldn't consider that 'powerful'. Tautologies may be fun philosophy, but
they have no place in the scientific method.

I agree. I have a B.S. in CSci and have taken both calc and discrete
math (matrices, combinatorics, etc.). But the physics stuff is somewhat
mystical to me. Operations and variables which aren't defined anywhere
in a key. I'm certain the math is not particularly profound, it's only
the shorthand that makes no sense to someone not accustomed to what each
symbol references. There should be a basic key somewhere, defining all
symbols and all operations beyond ordinary math (+, -, /, *, squares,
logs, trig, sums, limits, etc.)

If they'd demystify the damned formula, it might be open to greater
scrutiny -- but they seem to take delight in "you don't understand"'s.
Like the mystics of old, perhaps.

Paul Bramscher:

I agree. I have a B.S. in CSci and have taken both calc and discrete
math (matrices, combinatorics, etc.). But the physics stuff is somewhat
mystical to me. Operations and variables which aren't defined anywhere
in a key.

That's odd. I have lots of textbooks that define these things.
Do you expect every computer program to come with complete reference
to the language in which it's written and examples from the standards
committe regarding implementation issues? Do you expect every micro-
controller to use the same assembly instructions because no chip
vendor would consider it advantageous to exploit the advantages of
the chip if it meant being arcane?

I'm certain the math is not particularly profound, it's only
the shorthand that makes no sense to someone not accustomed to what each
symbol references. There should be a basic key somewhere, defining all
symbols and all operations beyond ordinary math (+, -, /, *, squares,
logs, trig, sums, limits, etc.)

Which ones in particular?

If they'd demystify the damned formula, it might be open to greater
scrutiny -- but they seem to take delight in "you don't understand"'s.
Like the mystics of old, perhaps.

There is nothing any more mystical about the formulae in physics
that there is in the difference between p, p[], *p, &p. If someone
walked up to you and said that programming was deliberately made
mysterious because he/she didn't understand the symbols, despite
having many years experience using word perfect,what do you suppose
you'd say?

Do you think that by simply telling someone the meaning of a
declaration, like: char (*(*x[3])())[5] (a real example from K&R), along
with a few syntax rules, that person will be able to write programs just
because he recite the definitions and type up something which is
syntactically correct using his vast word perfect computer experience?

If I tell you that a p/ (``p slash'') is the scalar product of a dirac
matrix and the four-momentum, are you going to be able to do relativistic
quantum mechanics? How about if I tell you the dirac matrices can be
obtained via the commtation and anti-commutation relations of the
coefficients in the dirac equation? How about if I also tell you what the
dirac equation is? What if I also tell you what that a commutator is like
a poisson bracket in classical physics? Basically, you are the equivalent
of the person described above who believes being able to program at the
level of a programmer only requires knowing a few definitions, some syntax
and combining it with several years of experience using word perfect to
type memos.

I'll define any formulae you wish, if you think it will help. However,
I think it's not going to help. Most physicists have to take at least
one night per month off from the constant drinking, womanizing and partying
in graduate school to work a homework problem in which these symbols
are occasionally used, in order to remember what the symbols look like.
If your schedule doesn't allow for that, you might have some difficulty.

Dear Bilge:

"Bilge" wrote in message
...
....
I'll define any formulae you wish, if you think it will help. However,
I think it's not going to help. Most physicists have to take at least
one night per month off from the constant drinking, womanizing and
partying
in graduate school to work a homework problem in which these symbols
are occasionally used, in order to remember what the symbols look like.
If your schedule doesn't allow for that, you might have some difficulty.

And *that* is why I went into mechanical engineering! ;)

David A. Smith

Bilge wrote:

Paul Bramscher:

I agree. I have a B.S. in CSci and have taken both calc and discrete
math (matrices, combinatorics, etc.). But the physics stuff is somewhat
mystical to me. Operations and variables which aren't defined anywhere
in a key.

That's odd. I have lots of textbooks that define these things.
Do you expect every computer program to come with complete reference
to the language in which it's written and examples from the standards
committe regarding implementation issues? Do you expect every micro-
controller to use the same assembly instructions because no chip
vendor would consider it advantageous to exploit the advantages of
the chip if it meant being arcane?

I'm certain the math is not particularly profound, it's only
the shorthand that makes no sense to someone not accustomed to what each
symbol references. There should be a basic key somewhere, defining all
symbols and all operations beyond ordinary math (+, -, /, *, squares,
logs, trig, sums, limits, etc.)

Which ones in particular?

If they'd demystify the damned formula, it might be open to greater
scrutiny -- but they seem to take delight in "you don't understand"'s.
Like the mystics of old, perhaps.

There is nothing any more mystical about the formulae in physics
that there is in the difference between p, p[], *p, &p. If someone
walked up to you and said that programming was deliberately made
mysterious because he/she didn't understand the symbols, despite
having many years experience using word perfect,what do you suppose
you'd say?

Depends on who my audience is. In programming we define our own
variables. I use meaningful names only.

I have no problem with physicsts using shortcuts for other physicists.
I've just not seen much effort to render much of QM -- in undiluted
format -- intelligible to someone with a reasonable amount of
math/science background, but not a physics background.

This is somewhat unique to physics. Most of the other sciences seem to
have a much more intelligible and universal symbolic math about them.


Do you think that by simply telling someone the meaning of a
declaration, like: char (*(*x[3])())[5] (a real example from K&R), along
with a few syntax rules, that person will be able to write programs just
because he recite the definitions and type up something which is
syntactically correct using his vast word perfect computer experience?

I never use "x", since it's totally devoid of any semantic content --
worthless by itself except as a placeholder. My variables read like a
book: fileName, author, title, annotation, booleanString, recordID, etc.
Most of the old c programmers write only for themselves (not even
other programmers).

So the example you cite above is unreadable without some deciphering,
overly obtuse, and semantically lacking at the same time. Why do it,
except for job security?

"Bill Hobba" wrote in message
...

"greywolf42" wrote in message
news
"Bill Hobba" wrote in message
...

{snip higher levels}

Please see the following ancient post by Tom Roberts:

http://groups.google.com/groups?q=ph...ty&hl=en&lr =
&group=sci.physics.relativity&selm=54jfst%24glp%40 ssbunews.ih.lucent.com&rnu
m=4

And note from the introduction:

'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].'

Unfortunately, that ancient post has been shown to be defective in
several respects. In this old derivation, Tom refers to 'coordinate
systems.' However, since that time, Tom has had to modify his
viewpoint to require 'inertial frames.'

There is no incompatibly between an inertial frame and inertial coordinate
system

No one said there was. But then, Tom's ancient post never mentioned
'inertial' coordinate systems. He had more general 'coordinate systems.'
Which was the point I was making.

- an inertial coordinate system is simply a (usually Cartesian)
system contained in an inertial frame.

That is a false statement. An inertial frame can contain a coordinate
system, and even an inertial coordinate system. But a coordinate system is
not presumed to extend rigidly through the entire universe. While an
'inertial frame' is presumed to extend rigidly throughout the universe.

Once Tom requires the Lorentz Transform (which is the
historical basis for the 'general symmetry properties of space-time'),
there's nothing left to do. Tom simply reversed the historical basis of
spacetime. Which is trivial, and meaningless.

So what you are saying is the derivation follows from the assumptions so
it is trivial and meaningless.

No, I'm saying that the paper assumes it's own conclusions as a starting
point. So the paper is trivial and meaningless. If the assumptions were
not originally based upon the conclusions that Tom wanted to obtain, then
the paper might have been useful.

--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

"Martin Hogbin" wrote in message
...

"greywolf42" wrote in message
...
"Martin Hogbin" wrote in message
...


OK, I accept all your notes. However, there aren't any measurements
that have been made in pure vacuum or in inertial frames.

Of course not, because there is no such think as a perfect
vacuum or inertial frame

Then you have no experimental basis for your claim that it never changes.

What specific, scientific support do you think you have?

just like there is no such thing as
a point mass, a frictionless surface or a massless inextensible
string. This is how physics works; we start with
idealisations and then add in the complications one by one.

That's the Platonic (philosophical) method, not the scientific method.

And it doesn't address your claim at all, either.

So where is your evidence?

I am sure you must be familiar with the evidence that supports
Einstein's postulate by now.

I'm not aware of any, that's the point. Every experiment that I've seen as
claimed support for SR, is only support for one leg of the Lorentz
transform -- not Einstein's. *YOU* are claiming that such support exists.
Where is it?

Your complaint seems to be that
none of the tests were performed in a perfect vacuum or an
inertial frame.

Nope. I never made this complaint.

This is true but, of course, the experimenters
(and later physicists) were aware of this.

I gave you many experiments that contradict your claim. You simply avoided
them by stating that they weren't done in a perfect inertial frame or a
perfect vacuum.

In some cases this
throws doubt on the validity of the results but it is possible to
calculate (independently of relativity)

What theory would you use to make this calculation?

the effects for example
of a medium on the speed of an electromagnetic wave and
in some cases this can be shown to be negligible.

We aren't discussing theoretical calculations of relativity.

This is no different to the evidence that supports Newtonian
physics.

Certainly it's different. We see a wavelike effect that changes just like
all other known wavelike effects. Newtonian dynamics can calculate wavelike
effects (including light, according to Maxwell's derivations). Now you make
a claim that light has a unique property that is not contained in any other
known physical process. Even though light otherwise acts just like every
other physical or wave property observed in the universe.

Where is your support for this unique claim?

It is never possible to do a perfect experiment;
we do the best we can and then try to estimate the causes of
error.

True, but irrelevant.

Quite simply, you have made a bald statement-by-assertion: "Light speed
is constant for all observers in an inertial frame in a pure vacuum."
Hence, it is up to you to support this claim.

You have, no doubt, seen the FAQ on this.

Yes. The FAQ smiply posts a bald claim -- without support. Statements by
authority (even if contained in a "FAQ") are not scientific support. It is
still up to you to support your claim.

--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

"Paul Bramscher" wrote in message
...
greywolf42 wrote:
"Paul Bramscher" wrote in message
...

{snip higher levels}

Perhaps many models describe an idealized and abstract set of
circumstances to one degree or another. I'm somewhat astounded how
idealized (non-extistent vaccuum) and how abstract (inertial frames)
this one happens to be.

This makes assumptions required for relativity very powerful (indeed,
non-falsifiable by empirical/experimental evidence), since conditions
sufficient to disprove this assumption are either non-existent or
arbitrary.

I wouldn't consider that 'powerful'. Tautologies may be fun philosophy,
but they have no place in the scientific method.

I agree. I have a B.S. in CSci and have taken both calc and discrete
math (matrices, combinatorics, etc.). But the physics stuff is somewhat
mystical to me. Operations and variables which aren't defined anywhere
in a key. I'm certain the math is not particularly profound, it's only
the shorthand that makes no sense to someone not accustomed to what each
symbol references. There should be a basic key somewhere, defining all
symbols and all operations beyond ordinary math (+, -, /, *, squares,
logs, trig, sums, limits, etc.)

If they'd demystify the damned formula, it might be open to greater
scrutiny -- but they seem to take delight in "you don't understand"'s.
Like the mystics of old, perhaps.

I agree that's one of the reasons. Other reasons include laziness (can't
be bothered to write out constants in equations); unwillingness to tolerate
contradictions (the units are wrong, but I want to use the equation anyway);
and Religion ('pure' math is more beautiful than 'messy' math).

--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}

"greywolf42" wrote in message .. .

Yes. The FAQ smiply posts a bald claim -- without support. Statements by
authority (even if contained in a "FAQ") are not scientific support. It is
still up to you to support your claim.


The link below gives a long list of experiments that support SR.
http://www.physics.adelaide.edu.au/~...periments.html

Martin Hogbin

"Martin Hogbin" wrote in message
...

"greywolf42" wrote in message
.. .

Ah, the standard Relativist snip-and-ignore.

Yes. The FAQ smiply posts a bald claim -- without support. Statements
by authority (even if contained in a "FAQ") are not scientific support.
It
is still up to you to support your claim.

The link below gives a long list of experiments that support SR.

http://www.physics.adelaide.edu.au/~...periments.html

1) None of these experiments address constant light speed in a vacuum.

2) They also support Lorentz' 1904 Electrodynamic theory.

I'm still waiting for you to support your explicit claim that light speed is
constant.

--
greywolf42
ubi dubium ibi libertas
{remove planet for e-mail}