Tom Roberts wrote in sci.physics.relativity:
David wrote:
If I have a disk that has a rotational velocity V at its outer
edge, does someone who is at rest with respect to the center of the
disk conclude that some sort of length contraction occurs because of V
and therefore the rotating disk has a smaller circumference than the
same disk when it is not rotating?

Normally when one says "the circumference of this disk", they mean a
measurement made _simultaneously_ around the entire edge of the disk.
For an inertial observer (e.g. of the inertial frame in which the center
is at rest) this is easy; for a rotating observer on the disk itself
this is impossible -- there is no single self-consistent definition of
simultaneity for a rotating system.

So you _must_ change your notion of what "circumference" means for a
rotating disk.

So for an inertial observer the measurement is easy but Tom Roberts the
relativist would never say "Length contraction occurs", or "Length
dilation occurs", or something similar to Einstein's conclusion in
Chapter 23 in Einstein's "Relativity", e.g. "Length contraction occurs
and therefore the circumference is longer than 2(pi)R which means that
length dilation occurs". The reason is that Chapter 23 is too idiotic
(Einstein's attempt to plagiarize Poincare was a total failure in this
case) and some relativists know that.

Pentcho Valev

"Pentcho Valev" wrote in message ups.com...
Tom Roberts wrote in sci.physics.relativity:
David wrote:
If I have a disk that has a rotational velocity V at its outer
edge, does someone who is at rest with respect to the center of the
disk conclude that some sort of length contraction occurs because of V
and therefore the rotating disk has a smaller circumference than the
same disk when it is not rotating?

Normally when one says "the circumference of this disk", they mean a
measurement made _simultaneously_ around the entire edge of the disk.
For an inertial observer (e.g. of the inertial frame in which the center
is at rest) this is easy; for a rotating observer on the disk itself
this is impossible -- there is no single self-consistent definition of
simultaneity for a rotating system.

So you _must_ change your notion of what "circumference" means for a
rotating disk.

So for an inertial observer the measurement is easy but Tom Roberts the
relativist would never say "Length contraction occurs", or "Length
dilation occurs", or something similar

Remember your heroic struggle with time constriction, imbecile?
http://groups.google.com/groups?q=au...v+constriction

Dirk Vdm

Pentcho Valev wrote:
Tom Roberts wrote in sci.physics.relativity:
David wrote:
If I have a disk that has a rotational velocity V at its outer
edge, does someone who is at rest with respect to the center of the
disk conclude that some sort of length contraction occurs because of V
and therefore the rotating disk has a smaller circumference than the
same disk when it is not rotating?

Normally when one says "the circumference of this disk", they mean a
measurement made _simultaneously_ around the entire edge of the disk.
For an inertial observer (e.g. of the inertial frame in which the center
is at rest) this is easy; for a rotating observer on the disk itself
this is impossible -- there is no single self-consistent definition of
simultaneity for a rotating system.

So you _must_ change your notion of what "circumference" means for a
rotating disk.

So for an inertial observer the measurement is easy but Tom Roberts the
relativist would never say "Length contraction occurs", or "Length
dilation occurs", or something similar to Einstein's conclusion in
Chapter 23 in Einstein's "Relativity", e.g. "Length contraction occurs
and therefore the circumference is longer than 2(pi)R which means that
length dilation occurs". The reason is that Chapter 23 is too idiotic
(Einstein's attempt to plagiarize Poincare was a total failure in this
case) and some relativists know that.

Pentcho Valev

Indeed... Einstein violates his own Chapter 17 admonition about
application of the imaginary operator:

To start with, he places one of two identically constructed
clocks at the centre of the circular disc, and the other on the
edge of the disc, so that they are at rest relative to it. We now
ask ourselves whether both clocks go at the same rate from the
standpoint of the non-rotating Galileian reference-body K. As
judged from this body, the clock at the centre of the disc has no
velocity, whereas the clock at the edge of the disc is in motion
relative to K in consequence of the rotation. According to a result
obtained in Section XII, it follows that the latter clock goes at a
rate permanently slower than that of the clock at the centre of the
circular disc, i.e. as observed from K. It is obvious that the same
effect would be noted by an observer whom we will imagine sitting
alongside his clock at the centre of the circular disc. Thus on our
circular disc, or, to make the case more general, in every
gravitational field, a clock will go more quickly or less quickly,
according to the position in which the clock is situated (at rest).
For this reason it is not possible to obtain a reasonable definition
of time with the aid of clocks which are arranged at rest with
respect to the body of reference. A similar difficulty presents
itself when we attempt to apply our earlier definition of
simultaneously
in such a case, but I do not wish to go any farther into this
question.
http://www.bartleby.com/173/23.html

The real Coulomb effects that attach to an observer of light
and also invoke application of a proper imaginary operator
are completly ignored.

"Incident Wave Impedance"
http://www.conformity.com/0102reflectionsfig3.gif
http://www.conformity.com/0102reflections.html
"Speed of Light"
http://www.nrao.edu/~smyers/courses/...edoflight.html

The false logic follows the same lines of the paper
"The Photoelectric effect" where a particle nature is concluded
because the writer can't think of any alternatives. Fortunately,
some scientists find that an unsatisfactory basis from which
to draw conclusions.

The Nobel Committee avoids committing itself to the
particle concept. Light-quanta or with modern terminology,
photons, were explicitly mentioned in the reports on
which the prize decision rested only in connection with
emission and absorption processes.
http://nobelprize.org/physics/articl...ong/index.html

Sue...

Pentcho Valev wrote:
Tom Roberts wrote in sci.physics.relativity:
David wrote:
If I have a disk that has a rotational velocity V at its outer
edge, does someone who is at rest with respect to the center of the
disk conclude that some sort of length contraction occurs because of V
and therefore the rotating disk has a smaller circumference than the
same disk when it is not rotating?
Normally when one says "the circumference of this disk", they mean a
measurement made _simultaneously_ around the entire edge of the disk.
For an inertial observer (e.g. of the inertial frame in which the center
is at rest) this is easy; for a rotating observer on the disk itself
this is impossible -- there is no single self-consistent definition of
simultaneity for a rotating system.

So you _must_ change your notion of what "circumference" means for a
rotating disk.

Tom Roberts continued:
| If instead of a solid disk you imagine a "disk" made up of thin radial
| fibers with increasing widths such that together they make up the disk
| when not rotating, then as the set of fibers starts rotating, small gaps
| will appear between the fibers, getting larger as the tangential velocity
| increases. Of course in practice this is immeasurably small, and for practical
| materials the fibers will be torn apart long before either an appreciable
| fraction of c is achieved or the gaps are observable.

Lorentz contraction of the fibres does occur.

So for an inertial observer the measurement is easy but Tom Roberts the
relativist would never say "Length contraction occurs", or "Length
dilation occurs", or something similar to Einstein's conclusion in
Chapter 23 in Einstein's "Relativity", e.g. "Length contraction occurs
and therefore the circumference is longer than 2(pi)R which means that
length dilation occurs".

So what's wrong with that?
In Tom's scenario, the Lorentz contraction of the fibres will
make gaps between the fibres.
But imagine that we have a circular slot in a very solid material.
In this slot there is a circular ribbon just fitting into the slot.
The ribbon is free of mechanical stresses when it is stationary.
So what happens when the ribbon is set in rapid rotation?
It will Lorentz contract, but since it is restricted by the slot, it is
not allowed to contract. So there will mechanical stress in the ribbon.
The ribbon will be mechanically stretched to compensate for the Lorentz
contraction. If you imagine that a number of short (compared to
the circumference) measuring rods were laid out end to end along
the ribbon, and moving along with the ribbon, these measuring rods
will be Lorentz contracted. So the observer on the ribbon will measure
the circumference to be longer than 2pi.r.
So indeed, a loose (and confusing) description of this might be:
"Length contraction occurs and therefore the circumference is longer
than 2(pi)R which means that length dilation occurs".
The "Length contraction" is a Lorentz contraction.
The "Length dilation" is a mechanical stretch.

The reason is that Chapter 23 is too idiotic
(Einstein's attempt to plagiarize Poincare was a total failure in this
case) and some relativists know that.

It's confusing maybe, but not idiotic.

Paul

"Paul B. Andersen" wrote in message
...
| Pentcho Valev wrote:
| Tom Roberts wrote in sci.physics.relativity:
| David wrote:
| If I have a disk that has a rotational velocity V at its outer
| edge, does someone who is at rest with respect to the center of the
| disk conclude that some sort of length contraction occurs because of V
| and therefore the rotating disk has a smaller circumference than the
| same disk when it is not rotating?
| Normally when one says "the circumference of this disk", they mean a
| measurement made _simultaneously_ around the entire edge of the disk.
| For an inertial observer (e.g. of the inertial frame in which the
center
| is at rest) this is easy; for a rotating observer on the disk itself
| this is impossible -- there is no single self-consistent definition of
| simultaneity for a rotating system.
|
| So you _must_ change your notion of what "circumference" means for a
| rotating disk.
|
| Tom Roberts continued:
|| If instead of a solid disk you imagine a "disk" made up of thin radial
|| fibers with increasing widths such that together they make up the disk
|| when not rotating, then as the set of fibers starts rotating, small gaps
|| will appear between the fibers, getting larger as the tangential velocity
|| increases. Of course in practice this is immeasurably small, and for
practical
|| materials the fibers will be torn apart long before either an appreciable
|| fraction of c is achieved or the gaps are observable.
|
| Lorentz contraction of the fibres does occur.
|
| So for an inertial observer the measurement is easy but Tom Roberts the
| relativist would never say "Length contraction occurs", or "Length
| dilation occurs", or something similar to Einstein's conclusion in
| Chapter 23 in Einstein's "Relativity", e.g. "Length contraction occurs
| and therefore the circumference is longer than 2(pi)R which means that
| length dilation occurs".
|
| So what's wrong with that?
| In Tom's scenario, the Lorentz contraction of the fibres will
| make gaps between the fibres.
| But imagine that we have a circular slot in a very solid material.
| In this slot there is a circular ribbon just fitting into the slot.
| The ribbon is free of mechanical stresses when it is stationary.
| So what happens when the ribbon is set in rapid rotation?
| It will Lorentz contract, but since it is restricted by the slot, it is
| not allowed to contract. So there will mechanical stress in the ribbon.
| The ribbon will be mechanically stretched to compensate for the Lorentz
| contraction. If you imagine that a number of short (compared to
| the circumference) measuring rods were laid out end to end along
| the ribbon, and moving along with the ribbon, these measuring rods
| will be Lorentz contracted. So the observer on the ribbon will measure
| the circumference to be longer than 2pi.r.
| So indeed, a loose (and confusing) description of this might be:
| "Length contraction occurs and therefore the circumference is longer
| than 2(pi)R which means that length dilation occurs".
| The "Length contraction" is a Lorentz contraction.
| The "Length dilation" is a mechanical stretch.
|
| The reason is that Chapter 23 is too idiotic
| (Einstein's attempt to plagiarize Poincare was a total failure in this
| case) and some relativists know that.
|
| It's confusing maybe, but not idiotic.
|
| Paul

Hahaha! It's idiotic, but not confusing. Back arsewards again, confused
idiot.

Paul B. Andersen wrote:
Pentcho Valev wrote:
Tom Roberts wrote in sci.physics.relativity:
David wrote:
If I have a disk that has a rotational velocity V at its outer
edge, does someone who is at rest with respect to the center of the
disk conclude that some sort of length contraction occurs because of V
and therefore the rotating disk has a smaller circumference than the
same disk when it is not rotating?
Normally when one says "the circumference of this disk", they mean a
measurement made _simultaneously_ around the entire edge of the disk.
For an inertial observer (e.g. of the inertial frame in which the center
is at rest) this is easy; for a rotating observer on the disk itself
this is impossible -- there is no single self-consistent definition of
simultaneity for a rotating system.

So you _must_ change your notion of what "circumference" means for a
rotating disk.

Tom Roberts continued:
| If instead of a solid disk you imagine a "disk" made up of thin radial
| fibers with increasing widths such that together they make up the disk
| when not rotating, then as the set of fibers starts rotating, small gaps
| will appear between the fibers, getting larger as the tangential velocity
| increases. Of course in practice this is immeasurably small, and for practical
| materials the fibers will be torn apart long before either an appreciable
| fraction of c is achieved or the gaps are observable.

Lorentz contraction of the fibres does occur.

So for an inertial observer the measurement is easy but Tom Roberts the
relativist would never say "Length contraction occurs", or "Length
dilation occurs", or something similar to Einstein's conclusion in
Chapter 23 in Einstein's "Relativity", e.g. "Length contraction occurs
and therefore the circumference is longer than 2(pi)R which means that
length dilation occurs".

So what's wrong with that?
In Tom's scenario, the Lorentz contraction of the fibres will
make gaps between the fibres.
But imagine that we have a circular slot in a very solid material.
In this slot there is a circular ribbon just fitting into the slot.
The ribbon is free of mechanical stresses when it is stationary.
So what happens when the ribbon is set in rapid rotation?
It will Lorentz contract, but since it is restricted by the slot, it is
not allowed to contract. So there will mechanical stress in the ribbon.
The ribbon will be mechanically stretched to compensate for the Lorentz
contraction. If you imagine that a number of short (compared to
the circumference) measuring rods were laid out end to end along
the ribbon, and moving along with the ribbon, these measuring rods
will be Lorentz contracted. So the observer on the ribbon will measure
the circumference to be longer than 2pi.r.
So indeed, a loose (and confusing) description of this might be:
"Length contraction occurs and therefore the circumference is longer
than 2(pi)R which means that length dilation occurs".
The "Length contraction" is a Lorentz contraction.
The "Length dilation" is a mechanical stretch.

The reason is that Chapter 23 is too idiotic
(Einstein's attempt to plagiarize Poincare was a total failure in this
case) and some relativists know that.

It's confusing maybe, but not idiotic.

Paul

Contriving a mechanism to rescue Einstein's absurd mechanism
hardly seems equivalent to a valid explanation in terms of Maxwell's
equations and the finite speed of light.

Sue...

"Sue..." wrote in message
oups.com...

[snip]