"SRdude" wrote in message oups.com...
.................Simple Math Derivation Needed..................

Even after deliberately disregarding all preceding and subsequent
words in the book, the fact remains that Einstein at one point
definitely derived the very simple equation w = c - v.

Here are his own words:
"w is the required velocity of light with respect to the carriage,
and we have w = c - v.
The velocity of propagation of a ray of light relative to the carriage
thus comes out smaller than c."
---------------http://www.bartleby.com/173/7.html---------------------
All I am looking for is one brave soul who will show this derivation.

Well, my dear Cadwgan Gedrych (aka Edward Travis (aka Ron
Aikas (aka Roy Royce (aka Martin Miller (aka John Reid (aka
Brian D. Jones)))))), this has been explained before.

This w is a so-called third party observed velocity:
http://hermes.physics.adelaide.edu.a...ght/FTL.html#2
It is the rate of change of a velocity between two things, as seen
by the observer on the embankment. The first object is a light
signal and the second object is the carriage.
The light signal has velocity c w.r.t. the embankment.
The carriage has velocity v w.r.t. the embankment.
After 0 seconds, the distance as calculated or measured by the
embankment between the signal and the carriage is 0 meters.
After 1 second, the distance is c meters - v meters = (c-v) meters.
After 2 seconds, the distance is 2c meters - 2v meters = 2(c-v) meters.
...
After t seconds, the distance is tc meters - tv meters = t(c-v) meters.
The distance between them "increases at a rate of c-v meters per
second". That is safer terminology than what Einstein used: "the
velocity of light with respect to the carriage".
But Einstein was talking to physicists, not to laymen.

See also
http://groups-beta.google.com/group/...8?dmode=source
and
http://groups-beta.google.com/group/...0?dmode=source

or on the original google groups (UK version):
http://groups.google.co.uk/groups?as...t01.boi.hp.com
and
elenet-ops.be

Dirk Vdm

Wrong answer, Dirk Vdm. (And I seriously doubt that anyone else
will concur with you.)

At that point in his book, Einstein had yet to even mention the
relativistic velocity composition theorem, let alone derive it.

w = c - v is a direct measurement of the one-way speed of a
departing light ray wrt a single frame (the carriage).

Further note, Dirk Vdm, that if the result had been - as you claim -
compatible with special relativity, then Einstein would not have
lamented that "...this result comes into conflict with the principle
of relativity...."

Quit trying to rewrite SR history in order to squirm out of my
challenge.

"SRdude" wrote in message oups.com...
Wrong answer, Dirk Vdm. (And I seriously doubt that anyone else
will concur with you.)

At that point in his book, Einstein had yet to even mention the
relativistic velocity composition theorem, let alone derive it.

Well, my dear troll (aka Cadwgan Gedrych (aka Edward Travis
(aka Ron Aikas (aka Roy Royce (aka Martin Miller (aka John
Reid (aka Brian D. Jones))))))), this has been explained befo
there is *nothing* relativistic to this derivation at all. It is not a
velocity composition *at all*.


w = c - v is a direct measurement of the one-way speed of a
departing light ray wrt a single frame (the carriage).

Well, my dear idiot (aka Cadwgan Gedrych (aka Edward Travis
(aka Ron Aikas (aka Roy Royce (aka Martin Miller (aka John
Reid (aka Brian D. Jones))))))), this has been explained befo
it is the distance between two objects having two different
velocities with respect to the same observer, exactly like I
explained it to you.


Further note, Dirk Vdm, that if the result had been - as you claim -
compatible with special relativity, then Einstein would not have
lamented that "...this result comes into conflict with the principle
of relativity...."

Well, my dear donkey (aka Cadwgan Gedrych (aka Edward Travis
(aka Ron Aikas (aka Roy Royce (aka Martin Miller (aka John
Reid (aka Brian D. Jones))))))), this has been explained befo
There is a huge difference between this "third party velocity" where
two object have two velocities w.r.t. one observer, and the other
case where one object has a velocity w.r.t. one oberserver, who
has in turn a velocity w.r.t. another observer.


Quit trying to rewrite SR history in order to squirm out of my
challenge.

Well, my dear bigot (aka Cadwgan Gedrych (aka Edward Travis
(aka Ron Aikas (aka Roy Royce (aka Martin Miller (aka John
Reid (aka Brian D. Jones))))))), this has been explained befo
quit showing how stupid you are and how little you even understand
of basic baby physics.

Dirk Vdm

"SRdude" wrote in message
oups.com...
Wrong answer, Dirk Vdm. (And I seriously doubt that anyone else
will concur with you.)

At that point in his book, Einstein had yet to even mention the
relativistic velocity composition theorem, let alone derive it.

w = c - v is a direct measurement of the one-way speed of a
departing light ray wrt a single frame (the carriage).

Further note, Dirk Vdm, that if the result had been - as you claim -
compatible with special relativity, then Einstein would not have
lamented that "...this result comes into conflict with the principle
of relativity...."

Quit trying to rewrite SR history in order to squirm out of my
challenge.

Quit trying to understand relativity buy reading Einstein's ancient popular
writings. Do something daring and study modern presentations.

http://arxiv.org/abs/physics/0110076,
and ancient, but I still think excellent post by Tom Roberts
http://groups.google.com/groups?hl=e....ih.lucent.com
and chapter 10 of
http://www.courses.fas.harvard.edu/~phys16/Textbook/
under the heading of Relativity without c.

However I have been dealing with cranks long enough on
sci.physics.relativity to know understanding relativity is not their aim.
This is the very reason they like to examine ancient popular writings.
Firstly it allows them to shift discussion to what Einstein may (and I
emphasis may) have thought 80 years ago rather that what we now know.
Secondly physicists have been known to be less than rigorous in what they
say in popular writings so they can pick up on such and claim it is some
fundamental problem with relativity.

Bill

Age, correctness, source, and whatever other straws you may
desperately try to grasp are all irrelevant; all that matters
is that somehow, somewhere, sometime, someone (named Einstein)
*derived* the simple equation w = c - v for light's one-way
speed wrt a carriage frame, and it is this very same derivation
that I want some brave relativist to step forward and show today.
Forget about all that modern junk. It has not a thing to do with
my challenge.

"SRdude" wrote in message
oups.com...
Wrong answer, Dirk Vdm. (And I seriously doubt that anyone else
will concur with you.)

You'll find Dinky van de Torquemada to be a bitter, twisted, pathetic
excuse for a turd, loaded with wrong answers.

At that point in his book, Einstein had yet to even mention the
relativistic velocity composition theorem, let alone derive it.

Here you have the better of me, I don't know to which book you
refer.
In "Electrodynamics"
ref http://www.fourmilab.ch/etexts/einstein/specrel/www/
he vagues refers to the PoR (his first postulate) by example of
the reciprocal action between a magnet and a conductor (it is
by relative movement between the two that produces a current),
states his second postulate and declares his intent to show
it is compatible with the first.
In section 3 he makes use of c+v in the equation
½[tau(0,0,0,t)+tau(0,0,0,t+x'/(c-v)+x'/(c+v))] = tau(x',0,0,t+x'/(c-v))
and derives 1/sqrt(1-v^2/c^2). This he then uses in section 5 to
give c = (c+v)/(1 +v/c), stating that his use of c+v in section 3 was
not legitimate.
In words, he states:
"But the ray moves relatively to the initial point of k, when measured
in the stationary system, with the velocity c-v, so that x'/(c-v) = t."
and
"It follows, further, that the velocity of light c cannot be altered by
composition with a velocity less than that of light.
For this case we obtain V = (c+w)/(1+w/c) = c."

w = c - v is a direct measurement of the one-way speed of a
departing light ray wrt a single frame (the carriage).

Further note, Dirk Vdm, that if the result had been - as you claim -
compatible with special relativity, then Einstein would not have
lamented that "...this result comes into conflict with the principle
of relativity...."

Which it does of course, although in 1905 he stated it was
"only apparently irreconcilable".


Ah... I googled the phrase and found your reference.
http://www.ivorix.com/en/einstein/contents/ch07.html
Relativity: The Special and General Theory © 1920
This is 15 years later.

"Prominent theoretical physicists were therefore more inclined to reject
the principle of relativity, in spite of the fact that no empirical data
had been
found which were contradictory to this principle. "

The empirical data was always there, it was misunderstood.
http://www.androc1es.pwp.blueyonder....ctual_data.htm
In 1920, "prominent theoretical physicists" (de Sitter notably)
lacked a computer to analyze the effect we can expect to see from
a point source of light moving in an elliptical orbit that obeys
Kepler's laws, preferring to believe what they see with their eyes
rather than a distortion caused by a varying speed of light.
http://www.ebicom.net/~rsf1/desit-1e.htm
Upon reading that article, you will find reference to Algol-type
variables which is embedded in the program Copernicus.exe.
http://www.androc1es.pwp.blueyonder....irus_alert.htm

What we have here is Einstein convincing deSitter who convinces
Einstein.
Androcles.

Quit trying to rewrite SR history in order to squirm out of my
challenge.
You are wasting your fingers typing anything to moortel.
Androcles.

"SRdude" wrote in message
oups.com...
Age, correctness, source, and whatever other straws you may
desperately try to grasp are all irrelevant; all that matters
is that somehow, somewhere, sometime, someone (named Einstein)
*derived* the simple equation w = c - v for light's one-way
speed wrt a carriage frame, and it is this very same derivation
that I want some brave relativist to step forward and show today.
Forget about all that modern junk. It has not a thing to do with
my challenge.

Oh but it does. As I said physicists have been known to be less than
rigorous in popular presentations so any problems you may find in those are
not worth much (and I emphasize MAY - in this case their is no problem). I
have read Dirks refutation and agree with it so it is not necessary for me
to go down that path. What is necessary if for people to understand the
attitude of cranks like yourself.

BTW if I recall correctly Einstein said it is the apparent velocity (ie the
velocity common sense tells us) of the velocity of light wrt to the frame.
This follows from the Galilean transformations usually assumed in physics
prior to relativity. However what experiment tells us is that a speed
exists that is measured the same in all inertial frames and to a very high
degree of accuracy that speed is found experimentally to be the speed of
light. Note that experiments to determine that speed need not have anything
to do with the speed of light eg the decay of muons can be used to determine
it. That such a speed exists (it may be infinity in which case the Galilean
transformations result) follows directly from the POR; which is a
foundational axiom of classical mechanics and something we have strong
experimental support for.

If Einstein said anything else than what I said above then he is wrong -
simple as that. Of course it is highly doubtful he would have - any claims
otherwise are simply misinterpretations trotted out for the purpose of
cranks.

Of course I do not expect someone of the ilk of this crank who posts under a
number of different names to understand it but the detail is fully developed
in the links I gave previously.

Bill

"SRdude" wrote in message oups.com...
Age, correctness, source, and whatever other straws you may
desperately try to grasp are all irrelevant; all that matters
is that somehow, somewhere, sometime, someone (named Einstein)
*derived* the simple equation w = c - v for light's one-way
speed wrt a carriage frame, and it is this very same derivation
that I want some brave relativist to step forward and show today.
Forget about all that modern junk. It has not a thing to do with
my challenge.

I have explained it often enough. I can't help it if you are
are so utterly hopelessly spectacularly stupid.
Actually ,I think you are even more stupid than Androcles.
I suggest that you give priority to trying to understand how
silly this one is:
http://users.pandora.be/vdmoortel/di...MathProof.html

Dirk Vdm

"Androcles" wrote in message . uk...

"SRdude" wrote in message
oups.com...
Wrong answer, Dirk Vdm. (And I seriously doubt that anyone else
will concur with you.)

You'll find Dinky van de Torquemada to be a bitter, twisted, pathetic
excuse for a turd, loaded with wrong answers.

Bitter?
You mean sweet:
http://www.google.com/search?&q=andr...ers.pandora.be

Dirk Vdm

"SRdude" wrote in message
oups.com...
Wrong answer, Dirk Vdm. (And I seriously doubt that anyone else
will concur with you.)

Dude, as usual with this kind of stuff, he is fully correct.
You should thank Dirk for patiently explaining to you the ABC of velocity
measurement.

At that point in his book, Einstein had yet to even mention the
relativistic velocity composition theorem, let alone derive it.

Exactly, Einstein *used* "c - v" for deriving that.

Harald