Starblade Darksquall wrote:

(Paul Cardinale) wrote in message . com...

Richard wrote in message ...

[snip]


Who knows? What I do know is that upon reflection, SR is incompatible
with any superluminal speed, even of a non-thing.

Wrong. As always. The speed limit of c in SR applies to matter,
energy, and information. The limit does not apply to interference
patterns, shadows, projections, and cuts.

Paul Cardinale


BTW, SR alone doesn't limit things to light speed. However, if we add
the restriction that there are no causal loops, IE, instances in which
a proceeds b, b proceeds c, and c proceeds a, then it does. However,
if Lorentz Symmetry was broken, like a spontaneously broken symmetry,
then this wouldn't necessarily be true.

(...Starblade Riven Darksquall...)

correct, what there doing is manipulating data transfer speeds.
see next post-it has become a concern to control light data to improve
efficiency.

holog

Starblade Darksquall wrote:
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.

You are not talking about the motion of the stars. You are talking about
changing coordinate systems.

Bob Kolker

Robert J. Kolker wrote:



Starblade Darksquall wrote:

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.


You are not talking about the motion of the stars. You are talking about
changing coordinate systems.

Bob Kolker

I thought he was just dizzy.

holog

holog wrote:

I thought he was just dizzy.

She

(Paul Cardinale) wrote in message . com...
Richard wrote in message ...

[snip]


Who knows? What I do know is that upon reflection, SR is incompatible
with any superluminal speed, even of a non-thing.

Wrong. As always. The speed limit of c in SR applies to matter,
energy, and information. The limit does not apply to interference
patterns, shadows, projections, and cuts.

Paul Cardinale

[EL]
Excuse me Paul Cardinale sir, but I am not used to read blabbering in
your posts, so are you fine!
If you are talking about another [c] else than the one that Maxwell
calculated from vacuum's permeability and permittivity then you should
let us know first but if it is the same thing as that then it is a
constant speed of electromagnetic waves' propagation in vacuum and it
is a scalar and it is a constant by definition that describes the
SPEED OF EM WAVES in vacuum.

It is not up to SR or you to decide what a constant by definition is
and we are not waiting for your consent either.

So it is not SR that limits "things" to [c] and it is definitely not
up to SR to assume authority to twist arbitrated standards.

Air-force jets do occasionally break the sound speed barrier because
sound has such a barrier speed limit and that is why it is breakable.
Similarly, electromagnetic waves do have a scalar speed in vacuum and
it is [c].

This means that it is forbidden for any electromagnetic field of any
topological form to propagate changes of state in vacuum at faster
than [c], so let us not play with words concerning delta-opposite
velocities, shadows, projections and patterns because that is
irrelevant and nonsensical as an argument for FASTER THAN LIGHT or you
would be comparing between oranges blue cheese cylindrical sectors.

As for your claim on matter, energy and information to be limited to
[c] I can hardly see how is that physics!

We have confidence that [c] is the maximal OBSERVABLE scalar speed of
electromagnetic wave's propagation in vacuum because we have
confidence that vacuum is the most primordial continuum of space.

Exceeding that speed by particles is to tear the fabric of that
continuum rendering it discontinuous, which is neither tenable nor
logically acceptable. Information in its purest form is a set of coded
time-dependant or space-dependant variations of state and information
itself does not propagate but the carrier of that information is what
propagates so there is no sense in claiming that SR limits what is
irrelevant to begin with.

I am sorry to have found your attack on Richard as mere emotional
blabbering.

EL

Perfectly Innocent:

I wonder if this is all nonsensical hoopla based on the antiquated
wave theory of light or if there is a real, measurable
faster-than-light particle view of quantum mechanical tunneling going
on.

What do you mean by 'faster than light'? SR does not forbid considering
things happening faster than light (eg the sweep of a torch over clouds) but
the sending of information faster then light is not what is allowed. The
effects your alluded to can not be used to send information faster than
light.

Thanks
Bill


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"Robert J. Kolker" wrote in message ...
Starblade Darksquall wrote:
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.

You are not talking about the motion of the stars. You are talking about
changing coordinate systems.

Bob Kolker

Motion is relative. They are not moving in their own reference frame,
but they are in mine.

(...Starblade Riven Darksquall...)

Sam Wormley wrote in message ...
holog wrote:

I thought he was just dizzy.

She

Thanks.

I really shouldn't spin around so much all the time.

(...Starblade Riven Darksquall...)

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.
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 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!