(EL) wrote in message . com...
Richard wrote in message ...

You are probably correct EL, but I don't believe that it's that
complicated. All you need to measure is the dispersion, from there you
can calculate the group velocity, as demonstrated nicely by this applet

http://gregegan.customer.netspace.ne...ETS/20/20.html

[EL]
Ah! The applet.
It is quite an amusing view, BUT.
Let us analyze that applet to find out how tricky wave mechanics can
be.
Firstly, that applet is simply a dynamic graph.
So let us assign some physical meanings to it before we proceed.
The horizontal axis should be definitely TIME.

BZZZZZT!

(Starblade Darksquall) wrote in message . com...
I know what goes faster than the speed of light.

The stars really really far from me all go faster than the speed of
light when I spin around in circles because my spinning reference
frame is just as good as anybody else's.

(...Starblade Riven Darksquall...)

Sure. From a non-inertial frame of reference, you can observe massive
objects traveling faster than c. So?

Richard wrote in message ...
EL wrote:

This restricts experiments to law frequency waves to guarantee that a
phase shift is that of a single wave, which is based on our empirical
knowledge that the wave must travel at less than [c] in caesium or any
medium other than vacuum.

So I was not surprised to read that they obtained a delay of 62 ns
inside the tube.

I tried to follow the equations but I stopped at being disgusted from
the relentless attempts to fit the results to a hypothesis.

Any way, thank you for your response Richard.

sigh

EL

You are probably correct EL, but I don't believe that it's that
complicated. All you need to measure is the dispersion, from there you
can calculate the group velocity, as demonstrated nicely by this applet

http://gregegan.customer.netspace.ne...ETS/20/20.html

According to the link on that page, the group velocity is given by

v_g = c / (n(v) + vdn(v)/dv)

and can be greater than c.

OTOH, I have a problem with their explanation of why this doesn't
contradict SR. Let's suppose that wrt some given wave the speed of the
group wave is less than c.

That supposition contradicts SR. Thus the richard perry has assumed his conclusion.

(Paul Cardinale)

Farted after a heavy meal and produced a congested sound

in message . com...


BZZZZZT!


[EL]
Ah!
I see that your knowledge is shrinking and your power of argumentation
have been reduced to what a fly can produce passing by an ear.

Good.

Then we have one less asshole cancelled from the list of the credible
scientists.

Bye.

EL

[EL]
Ah! The applet.
It is quite an amusing view, BUT.
Let us analyze that applet to find out how tricky wave mechanics can
be.
Firstly, that applet is simply a dynamic graph.
So let us assign some physical meanings to it before we proceed.
The horizontal axis should be definitely TIME.
The vertical axis could be the amplitude of differently offseted
waves.
This is rather very easy to demonstrate on a multi-channel
oscilloscope.
Since our screen image is a raster then the horizontal scan
time-window must be a single finite value.
Now let us assume that that oscilloscope's screen is subdivided
horizontally to 20 equal divisions.
We now lock our time-window onto twenty cycles of the highest
frequency displayed.
If it was for example 100MHz then each cycle takes 10 ns and we need a
horizontal sweep time of 200 ns.
That highest frequency must appear stationary on the scope's screen.
The applet shows a group of waves slipping backwards, which means that
they are slower than the reference frequency and the wavelengths are
not integer multiples of that wave length.
So we have a group of waves propagating at the same speed in the same
homogenous and isotropic medium but they have different frequencies
and they superimpose.
The group phase amplitude then is the sum of all superimposed phases
at any time. Therefore at any point in time we have a summed wave
propagating at [c] and the modulation is static over space while
changing over time.

Out of synch waves may slip backwards or forward depending on the sign
of the frequency delta with respect to the time-window of the
oscilloscope.
We chose for our example a 5 MHz reference frequency for the
oscilloscope and we choose our group to be based on a reference wave
frequency of 100 MHz and a band width less than 5MHz such that all
other group waves take frequencies less than 100 MHz but not less than
[95 MHz + epsilon].
This guaranties that the slipping effect is distributed over a single
division and is moving backwards (left side of screen).
The resulting interference-modulated wave, however, may be a new
frequency and we find Modulo 5 of that frequency to know the direction
of the slip of the resulting wave. If it was between .1 to 2.4 it
slips forward and if it was between 2.6 and to 4.9 it slips backwards.
The slipping speed is directly proportional to the delta of the modulo
and the horizontal scan frequency and it has absolutely nothing to do
with wave propagation time.

So this should take care of the fancy applet that means **** nothing
relevant to the being claimed hoopla.





According to the link on that page, the group velocity is given by

v_g = c / (n(v) + vdn(v)/dv)

and can be greater than c.

[EL]
What velocity is that v?
If it was the modulation frequency I fail to relate propagating it at
any other velocity than [c] in vacuum or less in caesium.
How in hell do they ambitiously wish to make us believe that a
modulation result at time [T] can appear forward at time [T- t]? All
interfering waves at any moment has a finite superposition and at the
next time event has another superposition that follows the first at
the same space coordinates while the previous one propagates at [c]
forward in space.
We either monitor space from an inertial frame and observe changes to
that locked space of time or we monitor time from a moving frame such
that we lock time [freeze time] and inspect a paper tape graph record
of changing space.

Doing both concurrently is reckless and irresponsible child's play.



OTOH, I have a problem with their explanation of why this doesn't
contradict SR. Let's suppose that wrt some given wave the speed of the
group wave is less than c. Thus wrt that wave a massive particle may be
moving in tandem with that group wave. According to SR velocity
addition, that particle is thus traveling at less than c wrt lab frame
as well, and thus the group wave is also moving at less than c wrt lab
frame because it is perpetually adjacent to the particle, which is
simply an invariant condition. Thus, according to SR and simple logic, a
group wave cannot move at greater than c wrt lab frame, 'unless' it is
also moving at greater than c wrt any single phase wave involved in the
group wave propagation. Thus the equation above cannot be
relativistically correct.

[EL]
The equation above is meaningless because I have no freaking idea how
they fill in the values of the variables.
That hoopla does not shake a hair.
Group velocity is an Oxymoron from scratch because there are no
different wave velocities in one and the same homogenous and isotropic
medium.
Any phase velocity expressed in distance over time is zero because a
phase change takes place at a fixed coordinate while the invariant
phase-state is what propagates space over time.
Therefore wave velocity in [L/T] dimensions is the same as the phase
velocity in [L/T] dimensions.
It is the phase rate of change in [L=0 /T] (we call it the Slew Rate)
that is erroneously labelled as a velocity.
It is in units of wave Amplitude/Time, like volts per second.



OTOH, there is no doubt that the group wave
can indeed empirically surpass c,

[EL]
Objection, because I have amply demonstrated that that is impossible
too.

so that if SR is valid, then there is
a speed of the group wave that cannot be accompanied by the moving
particle. Once again this can only result in the group wave propagating
at greater than c wrt 'all' frames at the very instant that it exceeds c
wrt any one frame.

[EL]
I am not a fan of SR either but c is a scalar constant of vacuum, and
we should never argue a constant by definition.
What is the meaning of group velocity!
Tow inertially locked light sources radiating expanding spherical
wavefronts must have the spherical shells approaching each other at 2c
by simple arithmetic. However, each sphere's radius must be increasing
length over time at [c].
I also give no flying monkey's fart to Einstein's observers and twins.

snip

It is easy to say, "Well, the SR speed limit applies only to massive
particles and information", it is quite another to prove that statement,
and to be quite honest, in retrospect, I've not only never seen such a
proof, I've never even seen a citation of such a proof. This seems to be
one of those, "well it sounds reasonable so it must be correct" laws.
Never once questioned as it is being questioned now. And it would seem
that it was very easy to discredit it all this time. Hmmm...Sometimes I
wonder if man will ever actually be even half of what believes himself
to be

Deal with that EL, and leave your condescending tone out of it, I didn't
buy. Superiority isn't a matter of one's technobabble cache'.

'sigh'

Richard Perry

[EL]
SR has nothing to do with asserting the fact that electromagnetic
waves propagate at c in vacuum.
You are giving Albert the credits of Maxwell by doing so.
There is nothing faster than light to accelerate anything faster than
light or are we going to violate the fact that energy may not be
created or destroyed now?

If you are driving a truck with speed limit 200 Km/h you may catch up
with a Fiat and give it a push and accelerate it to death, but when
you are in a Fiat how you, can catch up with a corvette zapping by at
180 km/h?
To apply a force to a particle you need to catch up with the particle
first and then push.
Nothing can be accelerated to more than [c] because [c] itself cannot
catch up with [c].

EL

EL wrote:

[EL]
Ah! The applet.
It is quite an amusing view, BUT.
Let us analyze that applet to find out how tricky wave mechanics can
be.
Firstly, that applet is simply a dynamic graph.
So let us assign some physical meanings to it before we proceed.
The horizontal axis should be definitely TIME.
The vertical axis could be the amplitude of differently offseted
waves.
This is rather very easy to demonstrate on a multi-channel
oscilloscope.
Since our screen image is a raster then the horizontal scan
time-window must be a single finite value.
Now let us assume that that oscilloscope's screen is subdivided
horizontally to 20 equal divisions.
We now lock our time-window onto twenty cycles of the highest
frequency displayed.
If it was for example 100MHz then each cycle takes 10 ns and we need a
horizontal sweep time of 200 ns.
That highest frequency must appear stationary on the scope's screen.
The applet shows a group of waves slipping backwards, which means that
they are slower than the reference frequency and the wavelengths are
not integer multiples of that wave length.
So we have a group of waves propagating at the same speed in the same
homogenous and isotropic medium but they have different frequencies
and they superimpose.
The group phase amplitude then is the sum of all superimposed phases
at any time. Therefore at any point in time we have a summed wave
propagating at [c] and the modulation is static over space while
changing over time.

Out of synch waves may slip backwards or forward depending on the sign
of the frequency delta with respect to the time-window of the
oscilloscope.
We chose for our example a 5 MHz reference frequency for the
oscilloscope and we choose our group to be based on a reference wave
frequency of 100 MHz and a band width less than 5MHz such that all
other group waves take frequencies less than 100 MHz but not less than
[95 MHz + epsilon].
This guaranties that the slipping effect is distributed over a single
division and is moving backwards (left side of screen).
The resulting interference-modulated wave, however, may be a new
frequency and we find Modulo 5 of that frequency to know the direction
of the slip of the resulting wave. If it was between .1 to 2.4 it
slips forward and if it was between 2.6 and to 4.9 it slips backwards.
The slipping speed is directly proportional to the delta of the modulo
and the horizontal scan frequency and it has absolutely nothing to do
with wave propagation time.

So this should take care of the fancy applet that means **** nothing
relevant to the being claimed hoopla.


According to the link on that page, the group velocity is given by

v_g = c / (n(v) + vdn(v)/dv)

and can be greater than c.

[EL]
What velocity is that v?
If it was the modulation frequency I fail to relate propagating it at
any other velocity than [c] in vacuum or less in caesium.
How in hell do they ambitiously wish to make us believe that a
modulation result at time [T] can appear forward at time [T- t]? All
interfering waves at any moment has a finite superposition and at the
next time event has another superposition that follows the first at
the same space coordinates while the previous one propagates at [c]
forward in space.
We either monitor space from an inertial frame and observe changes to
that locked space of time or we monitor time from a moving frame such
that we lock time [freeze time] and inspect a paper tape graph record
of changing space.

Doing both concurrently is reckless and irresponsible child's play.


OTOH, I have a problem with their explanation of why this doesn't
contradict SR. Let's suppose that wrt some given wave the speed of the
group wave is less than c. Thus wrt that wave a massive particle may be
moving in tandem with that group wave. According to SR velocity
addition, that particle is thus traveling at less than c wrt lab frame
as well, and thus the group wave is also moving at less than c wrt lab
frame because it is perpetually adjacent to the particle, which is
simply an invariant condition. Thus, according to SR and simple logic, a
group wave cannot move at greater than c wrt lab frame, 'unless' it is
also moving at greater than c wrt any single phase wave involved in the
group wave propagation. Thus the equation above cannot be
relativistically correct.

[EL]
The equation above is meaningless because I have no freaking idea how
they fill in the values of the variables.
That hoopla does not shake a hair.
Group velocity is an Oxymoron from scratch because there are no
different wave velocities in one and the same homogenous and isotropic
medium.
Any phase velocity expressed in distance over time is zero because a
phase change takes place at a fixed coordinate while the invariant
phase-state is what propagates space over time.
Therefore wave velocity in [L/T] dimensions is the same as the phase
velocity in [L/T] dimensions.
It is the phase rate of change in [L=0 /T] (we call it the Slew Rate)
that is erroneously labelled as a velocity.
It is in units of wave Amplitude/Time, like volts per second.

OTOH, there is no doubt that the group wave
can indeed empirically surpass c,

[EL]
Objection, because I have amply demonstrated that that is impossible
too.

so that if SR is valid, then there is
a speed of the group wave that cannot be accompanied by the moving
particle. Once again this can only result in the group wave propagating
at greater than c wrt 'all' frames at the very instant that it exceeds c
wrt any one frame.

[EL]
I am not a fan of SR either but c is a scalar constant of vacuum, and
we should never argue a constant by definition.
What is the meaning of group velocity!
Tow inertially locked light sources radiating expanding spherical
wavefronts must have the spherical shells approaching each other at 2c
by simple arithmetic. However, each sphere's radius must be increasing
length over time at [c].
I also give no flying monkey's fart to Einstein's observers and twins.

snip

It is easy to say, "Well, the SR speed limit applies only to massive
particles and information", it is quite another to prove that statement,
and to be quite honest, in retrospect, I've not only never seen such a
proof, I've never even seen a citation of such a proof. This seems to be
one of those, "well it sounds reasonable so it must be correct" laws.
Never once questioned as it is being questioned now. And it would seem
that it was very easy to discredit it all this time. Hmmm...Sometimes I
wonder if man will ever actually be even half of what believes himself
to be

Deal with that EL, and leave your condescending tone out of it, I didn't
buy. Superiority isn't a matter of one's technobabble cache'.

'sigh'

Richard Perry

[EL]
SR has nothing to do with asserting the fact that electromagnetic
waves propagate at c in vacuum.
You are giving Albert the credits of Maxwell by doing so.
There is nothing faster than light to accelerate anything faster than
light or are we going to violate the fact that energy may not be
created or destroyed now?

If you are driving a truck with speed limit 200 Km/h you may catch up
with a Fiat and give it a push and accelerate it to death, but when
you are in a Fiat how you, can catch up with a corvette zapping by at
180 km/h?
To apply a force to a particle you need to catch up with the particle
first and then push.
Nothing can be accelerated to more than [c] because [c] itself cannot
catch up with [c].

EL

My apologies EL, apparently I misread your reply. I mistook you for
the.... LOL, now I'm at a loss for a word to apply to them, I don't
regard them as enemies, even if that is functionally what they are,
enemies of truth, I guess. OTOH, as I said, the argument can be
transferred to the superluminal light beam spot, whether or not the
waves spoken of above are superluminal.

Here's something interesting to play with:

Suppose an observer is moving at 0.5c wrt lab frame. A superluminal beam
spot is moving wrt him at 2c.

Plugging these into the SR velocity equation:

W = (v+w)/(1 + vw/c^2)

gives

W ~ 2.5c

IOW we get a result that approximates normal velocity addition. I think
this is enough to show that the ticking rate dilations and length
contractions are now contradictory, since it is the same length of road,
fence, ground, etc. being contracted wrt the moving observer, by a
factor 1/gamma in the subluminal case, and virtually 1 in the
superluminal case. Different contractions, even though the observer
never changes speed wrt the background (lab frame).

Now plug in c and 'any' value, for v and w, in either order, you get

W=c

Thus even though a spot may be moving at any arbitrary speed wrt the
moving observer, including superluminally, then that same spot will be
moving at exactly c wrt lab frame. Thus it follows that all motions
occurring objectively wrt the moving observer are fictitious changes wrt
lab frame, since the lab frame observer sees all of these other points
(i.e. those that the moving observer sees as moving wrt him) as moving
at the same speed as the moving observer.

Need I continue?

Once again EL, pardon my grouping you in, I plead 'temporarily at my
wits end dealing with crackpots', hope you accept my sincerest apology
I've always found you to be one of the most level-headed amongst us, I
should've known better.

Richard Perry

Hello holog,

Why do people think if you go faster than light you can immediately go
back in time?
i.e. if you could travel at twice the speed of light it would still take
two years to get to alpha centuri, right?

That´s from the earth´s point of view. If you could travel to alpha
centauri at twice the speed of ligtht, the events "departure from
earth" and "arrival at alpha centauri" would be spacelike seperated
events. This means that their temporal sequence depends on the frame
of reference you choose. The violation of causality becomes obvious if
you immediately travel back from alpha centauri to earth, again at
twice the speed of light: Then your arrival on earth would be *before*
your departure from earth. SR avoids such violations of causality by
limiting the maximum speed at which you possibly can travel to the
speed of light.

regards,
Jürgen

Hello holog,

sorry, I made a mistake: Don´t travel to alpha centauri but rather to
a star which itself recedes from earth at *almost* the speed of light.
Let your speed be twice the speed of light *with respect to the earth*
for your way to the star and twice the speed of light *with respect to
this star* when you travel back to earth. Then you will come back
before you started.

regards,
Jürgen

Hello Richard,

[...]
Now as I see it, a group velocity was measured at greater than c, and
thus, in contrast to the Fizeau near fit, the relativistic velocity
addition equation fails in this current experiment. Not only that, but
the whole of special relativity has been proved false.

No, it hasn´t. SR forbids *transport of energy-momentum at
superluminal speeds*, and in the case of anomalous dispersion, as in
this experiment, energy-momentum is not transported with the group
velocity of the wave package. So superluminal group velocities don´t
violate SR.

regards,
Jürgen

(J?rgen Clade) wrote in message . com...
Hello holog,

Why do people think if you go faster than light you can immediately go
back in time?
i.e. if you could travel at twice the speed of light it would still take
two years to get to alpha centuri, right?

That´s from the earth´s point of view. If you could travel to alpha
centauri at twice the speed of ligtht, the events "departure from
earth" and "arrival at alpha centauri" would be spacelike seperated
events. This means that their temporal sequence depends on the frame
of reference you choose. The violation of causality becomes obvious if
you immediately travel back from alpha centauri to earth, again at
twice the speed of light: Then your arrival on earth would be *before*
your departure from earth. SR avoids such violations of causality by
limiting the maximum speed at which you possibly can travel to the
speed of light.

regards,
Jürgen

[EL]
Hi Jürgen,
I hope that you do not seriously believe in this chicken poop.
The distance between Earth and Alpha Centauri is a quantified
dimension of length that exists at once.
It is rather ridiculous to talk about a distance that shrinks in its
physical nature if an observer perceives it as shrunk.
Your perception may shrink indeed but the distance may not shrink and
if you do believe that poop then you do certainly need a shrink.

If the minimum distance is taken as a physical invariant then with a
constant velocity quantified in distance over time must take time by
simple division.

That time is a positive quantity that does not give a **** to who is
assigning a sign to it and who is observing it.
SR takes no credit for the constancy of electromagnetic waves in
vacuum but Maxwell does.
SR takes credit to the waste of time and bandwidth and the chicken
poop you posted.


EL