Androcles wrote:

"Jesse Mazer" wrote in message
...



Of course, before Einstein physicists didn't think Maxwell's laws
would be correct in every observer's reference frame--they thought
they would only hold exactly in the rest frame of the aether. They
would have believed that to state the laws of electromagnetism in a
way that would hold in all frames, you'd have to replace every x in
Maxwell's laws with (x - v*t), where v represents the observer's
velocity relative to the rest frame of the aether...any derivatives of
x would have to be replaced in the same way, like replacing dx/dt with
(dx/dt - v). This would give a new set of electromagnetic laws which
would be Galilei-invariant, and which would reduce to Maxwell's laws
in the case where v=0.

But a prediction of this Galilei-invariant analogue of Maxwell's laws
would be that for an observer in motion relative to the aether, light
will be observed to move at different speeds in different directions,
relative to himself. Unfortunately this was not supported by the
Michelson-Morley experiment.



The speed of light in diamond, water, air, any transparent medium is
constant with respect to the medium. MMX fails to support aether.
In MMX, the medium is air. It is as simple as that.


What do you mean "the medium is air"? My point was that when waves are
considered as a vibration in a medium, like sound waves, the speed of
any wave will be constant with respect to the rest frame of the medium.
I assume you're not saying light waves are just vibrations in the air?






Androcles proposes to explain this negative result with the suggestion
that the velocity of light depends on the velocity of the source,


Since source, medium and detector are all relatively at rest, MMX
disposes of the aether only.
1) speed of light relative to source.
2) speed of light relative to medium.
3) speed of light relative to detector.


MMX satisfies all three.
SR fails to satisfy MMX, however.


What do you mean by "satisfies all three"? Those are sentence fragments,
I don't know what it would mean to satisfy "speed of light relative to
detector", for example.

In any case, if you're just saying MMX is consistent with your idea that
the speed of light depends on the source velocity, I wouldn't disagree,
but the point is that Maxwell's laws are *not* consistent with that
idea, whether you assume Maxwell's laws hold in all frames (as in
relativity) or you assume they only hold in a particular frame, and you
have to do a Galilei transform on them to describe E&M in other frames
(as physicists assumed would be true before relativity). Maxwell's laws
are very successful at predicting all sorts of electromagnetic behavior,
so if you want to throw them out, you'd better have a good alternative
which can make most of the same predictions.




but this would be false according to both Maxwell's laws *and* the
modified Galilei-invariant analogue of Maxwell's laws (which says that
light waves, like sound waves, always travel at the same speed in the
rest frame of the aether/air,



Forget aether, it doesn't exist. Air does, though. So does water.
A stick passing through the air-water interface appears bent.
That is empirical evidence that the speed of light is medium dependent.


I don't think aether exists either, I was just describing what would be
predicted by the modified Galilei-invariant analogue of Maxwell's laws
which physicists believed in before relativity.






regardless of the velocity of their source).



Source dependency only applies in the absence of a medium. There is
no aether.


Both Maxwell's laws and the Galilei-invariant analogue of Maxwell's laws
predict that the velocity of a light wave is independent of the velocity
of the source. This can be proved mathematically just by looking at the
equations of the laws, it's irrelevant whether you conceive of these
laws as describing "vibrations in aether" or if you conceive of them in
a different way.






So unless he can find a theory that gives correct predictions for all
the various experiments in classical electromagnetism, and yet does
not have the feature that the velocity of light is independent of the
source velocity, then his ideas wouldn't even have seemed plausible to
a physicist in a time before the theory of relativity had been
published (but after the Michelson-Morley experiment had been done).



Nobody has a computer then. Today we can calculate what the result
would be if a bullet stream from a moving machine gun moving in an
elliptical
orbit that obeyed Kepler's laws were to arrive at any distance.
The intensity of arriving bullets (grey line) looks like this.


http://www.androc1es.pwp.blueyonder....r/V1493Aql.JPG

If you examine the image closely, you'll see a crossover where the
faster bullets
has caught up with and passed the slower bullets.
That is a simple distance / time plot, distance vertical and time
horizontal.
What you would see is a sudden increase in the rate of arrival of
bullets,
then a second maximum, eventually tailing off.
A star in elliptical orbit would do the same thing.
Androcles.






What does this have to do with the comment you were responding to?
Either you have a complete theory of electromagnetism, which can make
correct predictions about all the experiments in classical
electromagnetism that have been done to date (which Maxwell's laws can
do), or you don't. And I'm pretty sure you don't. So why would you
expect physicists to abandon Maxwell's laws in favor of your ideas?

Jesse

"Timo Nieminen" wrote in message
news:Pine.LNX.4.50.0501111129440.1887-100000@localhost...
On Tue, 11 Jan 2005, Androcles wrote:

"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:

The speed of light in diamond, water, air, any transparent medium
is
constant with respect to the medium.

Loosely phrased, and wrong. The phase speed of light of a given
frequency
in diamond, water, air, any stationary medium, is constant with
respect to
the stationary medium.

Good enough to explain MMX.

So is SR, so is a fully-dragged Galilean ether, so is a Lorentz
ruler-shrinking clock-slowing ether, and so is just about any emission
theory.

Ordinarily, it would be somewhat pedantic point, but empirical
observations of the speed of light in a moving medium were
historically
important, and continue to be theoretically important, in chosing
which of
the above explanations of MMX could be correct. In the context of
using an
emission theory to explain MMX, it's a worthwhile point.

SR isn't good enough, and doesn't.
Hint: the fringe shift is a beat frequency.
Androcles.

"Androcles" wrote in message k...

"Timo Nieminen" wrote in message
news:Pine.LNX.4.50.0501111102040.1887-100000@localhost...
On Tue, 11 Jan 2005, Androcles wrote:

The speed of light in diamond, water, air, any transparent medium is
constant with respect to the medium.

Loosely phrased, and wrong. The phase speed of light of a given
frequency
in diamond, water, air, any stationary medium, is constant with
respect to
the stationary medium.

--
Timo Nieminen - Home page:
http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits:
http://www.users.bigpond.com/timo_nieminen/spirits.html

Good enough to explain MMX.
Androcles.

Just like this picture is good enough to illustrate MMX:
http://www.androc1es.pwp.blueyonder.co.uk/MMX.GIF
http://users.pandora.be/vdmoortel/di.../AndroMMX.html
;-)

Dirk Vdm

Androcles wrote:




I don't believe in magic. If c = c+v and c = c-v, then v = 0.
If V = (c+v)/(1+v/c) then use that to derive the LTs.
If the system of equations is linear as Einstein claims, it shoud be
no trouble.

....

If you can use
1/2[tau(0,0,0,t)+tau(0,0,0,t+x'/V+x'/V)] = tau(x',0,0,t+x'/V)
since "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."
to derive the Lorentz Transforms, I'll take another look.

Go ahead. I'm amenable to reason.
Explain to me how the two velocities of light, c-v and c+v, measured
over a single distance, are really only one, c.


OK, so in these quotes you asked me to derive the Lorentz
transformations from V = (c+v)/(1+v/c), but like I said, I'm not sure
what you meant by this, since by simple algebra (c+v)/(1+v/c) reduces to
c, so this equation is really just V = c. Again, were you just asking if
I could derive the LTs from the assumption that the velocity of light
must be the same in all reference frames? If not, please explain exactly
what starting assumption you were asking me to derive the Lorentz
transformations from, if you were serious about being "amenable to reason".

Jesse

"Jesse Mazer" wrote in message
...


Androcles wrote:

"Jesse Mazer" wrote in message
...


Of course, before Einstein physicists didn't think Maxwell's laws
would be correct in every observer's reference frame--they thought
they would only hold exactly in the rest frame of the aether. They
would have believed that to state the laws of electromagnetism in a
way that would hold in all frames, you'd have to replace every x in
Maxwell's laws with (x - v*t), where v represents the observer's
velocity relative to the rest frame of the aether...any derivatives
of x would have to be replaced in the same way, like replacing dx/dt
with (dx/dt - v). This would give a new set of electromagnetic laws
which would be Galilei-invariant, and which would reduce to Maxwell's
laws in the case where v=0.

But a prediction of this Galilei-invariant analogue of Maxwell's laws
would be that for an observer in motion relative to the aether, light
will be observed to move at different speeds in different directions,
relative to himself. Unfortunately this was not supported by the
Michelson-Morley experiment.


The speed of light in diamond, water, air, any transparent medium is
constant with respect to the medium. MMX fails to support aether.
In MMX, the medium is air. It is as simple as that.


What do you mean "the medium is air"?

I mean that air was used as a medium for light,
by Michelson, in his interferometer, of course.
He did not perform the experiment in an evacuated chamber, on the
surface
of the moon, or aboard the ISS.



My point was that when waves are considered as a vibration in a
medium, like sound waves, the speed of any wave will be constant with
respect to the rest frame of the medium.

Your points are invariance, x-vt, Maxwell's laws, derivatives, aether
and
anything else you can mention hoping to cover the issue, but you omitted
to say anything about the physical medium used and asked me what I
meant by it, so clearly it was NOT your point, it is MY point.

Recall that Einstein's second postulate is
"light is always propagated in empty space with a definite velocity c
which is independent of the state of motion of the emitting body".

It is not "light is always propagated in air with a definite velocity c
which is independent of the state of motion of the emitting body".

MMX has nothing to do with SR at all.

I assume you're not saying light waves are just vibrations in the air?

You can assume I'm not a fool. That's about all you can assume abut me.



Androcles proposes to explain this negative result with the
suggestion that the velocity of light depends on the velocity of the
source,

Since source, medium and detector are all relatively at rest, MMX
disposes of the aether only.
1) speed of light relative to source.
2) speed of light relative to medium.
3) speed of light relative to detector.


MMX satisfies all three.
SR fails to satisfy MMX, however.


What do you mean by "satisfies all three"? Those are sentence
fragments, I don't know what it would mean to satisfy "speed of light
relative to detector", for example.

All speeds are relative to something.
When requesting a drink on a plane, my speed relative to the flight
attendant is also zero, even though travelling at 500 mph ground speed
and 250 mph by the air speed indicator.
The speed of light inside a plane, as with the speed of sound, is
relative.
There is no doppler shift to observe for either sound or light, nor do
I expect there to be.
MMX is an attempt to measure doppler shift. It failed.
There is no aether.
Shall I then say, the speed of sound is invariant because there is no
doppler shift aboard a plane?


In any case, if you're just saying MMX is consistent with your idea
that the speed of light depends on the source velocity, I wouldn't
disagree,

Good. So why complicate matters?
"Everything should be made as simple as possible, but not
simpler." -Einstein.
Pity he didn't take his own advice.

but the point is that Maxwell's laws are *not* consistent with that
idea,

"It is known that Maxwell's electrodynamics--as usually understood
at the present time--when applied to moving bodies, leads to
asymmetries
which do not appear to be inherent in the phenomena." - Einstein.

"It is known that Einstein's electrodynamics--as usually understood
at the present time--when applied to moving bodies, leads to
asymmetries
which do not appear to be inherent in the phenomena" - Androcles.

So, something is wrong with Maxwell's equations that Einstein attempts
to fix, but in doing so introduces absurdities that are obvious to the
meanest intelligence, but accepted by "theoretical" physicists. Wrong
fix.
Maxwell was an aetherialist, and there is no aether.


whether you assume Maxwell's laws hold in all frames (as in
relativity) or you assume they only hold in a particular frame, and
you have to do a Galilei transform on them to describe E&M in other
frames (as physicists assumed would be true before relativity).
Maxwell's laws are very successful at predicting all sorts of
electromagnetic behavior, so if you want to throw them out, you'd
better have a good alternative which can make most of the same
predictions.

I do.



but this would be false according to both Maxwell's laws *and* the
modified Galilei-invariant analogue of Maxwell's laws (which says
that light waves, like sound waves, always travel at the same speed
in the rest frame of the aether/air,


Forget aether, it doesn't exist. Air does, though. So does water.
A stick passing through the air-water interface appears bent.
That is empirical evidence that the speed of light is medium
dependent.


I don't think aether exists either, I was just describing what would
be predicted by the modified Galilei-invariant analogue of Maxwell's
laws which physicists believed in before relativity.

What Galilean invariance are you talking about?
Time, length and mass are invariant. length/time is not, time/mass is
not,
mass/length is not.






regardless of the velocity of their source).


Source dependency only applies in the absence of a medium. There is
no aether.


Both Maxwell's laws and the Galilei-invariant analogue of Maxwell's
laws predict that the velocity of a light wave is independent of the
velocity of the source.

You have yet to show what you mean by "Galilei-invariant analogue "


This can be proved mathematically just by looking at the equations of
the laws, it's irrelevant whether you conceive of these laws as
describing "vibrations in aether" or if you conceive of them in a
different way.

I conceive of them a different way, and you will not mathematically
disprove that dfferent way.



So unless he can find a theory that gives correct predictions for all
the various experiments in classical electromagnetism, and yet does
not have the feature that the velocity of light is independent of the
source velocity, then his ideas wouldn't even have seemed plausible
to a physicist in a time before the theory of relativity had been
published (but after the Michelson-Morley experiment had been done).


Nobody has a computer then. Today we can calculate what the result
would be if a bullet stream from a moving machine gun moving in an
elliptical
orbit that obeyed Kepler's laws were to arrive at any distance.
The intensity of arriving bullets (grey line) looks like this.


http://www.androc1es.pwp.blueyonder....r/V1493Aql.JPG

If you examine the image closely, you'll see a crossover where the
faster bullets
has caught up with and passed the slower bullets.
That is a simple distance / time plot, distance vertical and time
horizontal.
What you would see is a sudden increase in the rate of arrival of
bullets,
then a second maximum, eventually tailing off.
A star in elliptical orbit would do the same thing.
Androcles.





What does this have to do with the comment you were responding to?
Either you have a complete theory of electromagnetism, which can make
correct predictions about all the experiments in classical
electromagnetism that have been done to date (which Maxwell's laws can
do), or you don't. And I'm pretty sure you don't.

Guessing again, are you not?


So why would you expect physicists to abandon Maxwell's laws in favor
of your ideas?

You did not address the point I made. How can you expect to know
what a physicist will accept without being aware if what I have said?
I'll repeat:
Today we can calculate what the result would be if a bullet stream
from a moving machine gun moving in an elliptical orbit that obeyed
Kepler's laws were to arrive at any distance.
The intensity of arriving bullets (grey line) looks like this.


http://www.androc1es.pwp.blueyonder....r/V1493Aql.JPG

If you examine the image closely, you'll see a crossover where the
faster bullets has caught up with and passed the slower bullets.
That is a simple distance / time plot, distance vertical and time
horizontal.
What you would see is a sudden increase in the rate of arrival of
bullets, then a second maximum, eventually tailing off.

A star in elliptical orbit would do the same thing.
Androcles.

Androcles wrote:

"Jesse Mazer" wrote in message
...


Androcles wrote:



"Jesse Mazer" wrote in message
...




Of course, before Einstein physicists didn't think Maxwell's laws
would be correct in every observer's reference frame--they thought
they would only hold exactly in the rest frame of the aether. They
would have believed that to state the laws of electromagnetism in a
way that would hold in all frames, you'd have to replace every x in
Maxwell's laws with (x - v*t), where v represents the observer's
velocity relative to the rest frame of the aether...any derivatives
of x would have to be replaced in the same way, like replacing dx/dt
with (dx/dt - v). This would give a new set of electromagnetic laws
which would be Galilei-invariant, and which would reduce to Maxwell's
laws in the case where v=0.

But a prediction of this Galilei-invariant analogue of Maxwell's laws
would be that for an observer in motion relative to the aether, light
will be observed to move at different speeds in different directions,
relative to himself. Unfortunately this was not supported by the
Michelson-Morley experiment.



The speed of light in diamond, water, air, any transparent medium is
constant with respect to the medium. MMX fails to support aether.
In MMX, the medium is air. It is as simple as that.



What do you mean "the medium is air"?



I mean that air was used as a medium for light,
by Michelson, in his interferometer, of course.
He did not perform the experiment in an evacuated chamber, on the
surface
of the moon, or aboard the ISS.





My point was that when waves are considered as a vibration in a
medium, like sound waves, the speed of any wave will be constant with
respect to the rest frame of the medium.



Your points are invariance, x-vt, Maxwell's laws, derivatives, aether
and
anything else you can mention hoping to cover the issue, but you omitted
to say anything about the physical medium used and asked me what I
meant by it, so clearly it was NOT your point, it is MY point.

Recall that Einstein's second postulate is
"light is always propagated in empty space with a definite velocity c
which is independent of the state of motion of the emitting body".


Maxwell's laws also say that light's velocity is independent of the
state of motion of the emitting body, regardless of whether you have the
relativistic understanding of these laws (that they hold in all
reference frames) or the pre-relativistic understanding of them (that
they only hold in one preferred frame, and in other frames the velocity
of light would be c+v in one direction and c-v in the other).




All speeds are relative to something.
When requesting a drink on a plane, my speed relative to the flight
attendant is also zero, even though travelling at 500 mph ground speed
and 250 mph by the air speed indicator.
The speed of light inside a plane, as with the speed of sound, is
relative.


That's because the plane carries its own little pocket of air with it,
so inside the plane you are at rest relative the local medium. If you
were skydiving and you tried to yell out to a fellow skydiver below you,
if you were both moving down at velocity v relative to the rest frame of
the atmosphere, then you would observe the soundwaves to be going at s-v
downward and s+v upwards, in your reference frame (s is the speed of
sound in the air's rest frame).

There were some attempts to explain the MMX by suggesting the earth
dragged a pocket of aether along with it as it orbited, just like a
plane carries a pocket of air, so people on earth were always at rest in
relation to the local aether.

There is no doppler shift to observe for either sound or light, nor do
I expect there to be.
MMX is an attempt to measure doppler shift. It failed.


No it isn't. Doppler shift is only about change in frequency--you tried
to prove otherwise with an equation, but you didn't answer where you got
the equation when I asked (it was not the same as the doppler shift
equation I found when I looked it up), and I also didn't understand how
you were trying to use it to prove that the frequency wouldn't change.

Would you agree that if I hear the whistle of a train coming towards me,
the pitch will be changed but the speed of the sound wave will not be an
different than the speed of a sound wave from a train standing still?


There is no aether.
Shall I then say, the speed of sound is invariant because there is no
doppler shift aboard a plane?


Again, the explanation for that is just that the plane carries its own
pocket of air along with it, so you are still at rest relative to the
medium of soundwaves inside the plane.





In any case, if you're just saying MMX is consistent with your idea
that the speed of light depends on the source velocity, I wouldn't
disagree,



Good. So why complicate matters?
"Everything should be made as simple as possible, but not
simpler." -Einstein.
Pity he didn't take his own advice.



but the point is that Maxwell's laws are *not* consistent with that
idea,



"It is known that Maxwell's electrodynamics--as usually understood
at the present time--when applied to moving bodies, leads to
asymmetries
which do not appear to be inherent in the phenomena." - Einstein.

"It is known that Einstein's electrodynamics--as usually understood
at the present time--when applied to moving bodies, leads to
asymmetries
which do not appear to be inherent in the phenomena" - Androcles.

So, something is wrong with Maxwell's equations that Einstein attempts
to fix, but in doing so introduces absurdities that are obvious to the
meanest intelligence, but accepted by "theoretical" physicists. Wrong
fix.
Maxwell was an aetherialist, and there is no aether.



Maxwell's laws are just equations for predicting the dynamical behavior
of a system of charges. It is totally irrelevant whether you interpret
them in terms of aether or not.

Again, when Einstein said "as usually understood at the present time",
he was referring to the idea that Maxwell's laws would only hold in a
single preferred reference frame (which most physicists imagined to be
the rest frame of the aether, but again, this is irrelevant) and in
other frames they'd have to be modified using the Galilei transformation
(substituting x + vt for x in the equations).





whether you assume Maxwell's laws hold in all frames (as in
relativity) or you assume they only hold in a particular frame, and
you have to do a Galilei transform on them to describe E&M in other
frames (as physicists assumed would be true before relativity).
Maxwell's laws are very successful at predicting all sorts of
electromagnetic behavior, so if you want to throw them out, you'd
better have a good alternative which can make most of the same
predictions.



I do.


OK, present the complete equations of your theory, that I can use to
calculate the dynamics of an arbitrary system of moving charges.
Otherwise no, you don't.







but this would be false according to both Maxwell's laws *and* the
modified Galilei-invariant analogue of Maxwell's laws (which says
that light waves, like sound waves, always travel at the same speed
in the rest frame of the aether/air,



Forget aether, it doesn't exist. Air does, though. So does water.
A stick passing through the air-water interface appears bent.
That is empirical evidence that the speed of light is medium
dependent.



I don't think aether exists either, I was just describing what would
be predicted by the modified Galilei-invariant analogue of Maxwell's
laws which physicists believed in before relativity.



What Galilean invariance are you talking about?
Time, length and mass are invariant. length/time is not, time/mass is
not,
mass/length is not.


I already explained Galilean invariance in a previous post. Here's the
definition of a Galilei transformation again, followed by an explanation
of what it means for a set of laws to be Galilei-invariant:

x'=x - vt
y'=y
z'=z
t'=t

x=x' + vt'
y=y'
z=z'
t=t'

To say a certain physical equation is "Galilei-invariant" just means the
form of the equation is unchanged if you make these substitutions. For
example, suppose at time t you have a mass m1 at position (x1, y1, z1)
and another mass m2 at position (x2, y2, z2) in your reference frame.
Then the Newtonian equation for the gravitational force between them
would be:

F = Gm1m2/[(x1 - x2)2 + (y1 - y2)2 + (z1 - z2)2]

Now, suppose we want to transform into a new coordinate system moving at
velocity v with respect to the first one. In this coordinate system, at
time t' the mass m1 has coordinates (x1', y1', z1') and the mass m2 has
coordinates (x2', y2', z2'). Using the Galilei transformations, we can
figure how the force would look in this new coordinate system, by
substituting in x1 = x1' + vt', x2 = x2' + vt', y1 = y1', y2 = y2', and
so forth. With these substitutions, the above equation becomes:

F = Gm1m2/[(x1' + vt' - (x2' + vt'))2 + (y1' - y2')2 + (z1' - z2')2]

and you can see that this simplifies to:

F = Gm1m2/[(x1' - x2')2 + (y1' - y2')2 + (z1' - z2')2]

In other words, the equation has exactly the same form in both
coordinate systems. This is what it means to be "Galilei invariant".
More generally, if you have *any* physical equation which computes some
quantity (say, force) as a function of various space and time
coordinates, like f(x,y,z,t) [of course it may have more than one of
each coordinate, like the x1 and x2 above, and it may be a function of
additional variables as well, like m1 and m2 above] then for this
equation to be "Galilei invariant", it must satisfy:
f(x'+vt',y',z',t') = f(x',y',z',t')


And to clear up a point you misunderstood earlier, the statement "f(x' +
vt',y',z',t') = f(x',y',z',t')" must hold true for *all* values of v in
order for a given physics equation to have the property of "Galilei
invariance".

Maxwell's laws are not Galilei-invariant, but if you take the equations
of Maxwell's laws and replace x with x + vt, and dx/dt with dx/dt + v (I
got the sign wrong in the other post), then this modified version of
Maxwell's laws should have the property of Galilei-invariance (for
example, since the ordinary version of Maxwell's laws predicts that
dx/dt = c for an electromagnetic wave, these modified laws would say
that dx/dt + v = c, which means that the velocity of the wave will be
dx/dt = c - v, if you are in a frame moving at v with respect to the
preferred frame where Maxwell's laws hold exactly). As I said before,
the common belief about Maxwell's laws before Einstein was that they
would only hold in a preferred frame, so if you jumped to a different
frame which was related to the preferred frame by a certain Galilei
transformation, you'd have to use these modified Maxwell's equations to
make predictions about electromagnetic behavior in your frame.









regardless of the velocity of their source).



Source dependency only applies in the absence of a medium. There is
no aether.



Both Maxwell's laws and the Galilei-invariant analogue of Maxwell's
laws predict that the velocity of a light wave is independent of the
velocity of the source.



You have yet to show what you mean by "Galilei-invariant analogue "


I have explained several times that if you substitute x + vt for x in
Maxwell's equations, and dx/dt + v for dx/dt (I actually said x - vt and
dx/dt - v earlier, but that was a sign mistake), you should get an
analogue of Maxwell's laws that is Galilei-invariant.






This can be proved mathematically just by looking at the equations of
the laws, it's irrelevant whether you conceive of these laws as
describing "vibrations in aether" or if you conceive of them in a
different way.



I conceive of them a different way, and you will not mathematically
disprove that dfferent way.


You can't mathematically prove or disprove a physical theory, only that
the theory makes certain predictions, which could be right or wrong. Do
you agree that Maxwell's laws predict, rightly or wrongly, that the
velocity of an electromagnetic wave such as light is always independent
of the velocity of the source, regardless of whether you take the
relativistic view that Maxwell's laws work in every frame, or the
pre-relativistic view that they only hold exactly in a certain preferred
frame, and that in other frames the velocity of light would be c+v in
one direction and c-v in the other?





So unless he can find a theory that gives correct predictions for all
the various experiments in classical electromagnetism, and yet does
not have the feature that the velocity of light is independent of the
source velocity, then his ideas wouldn't even have seemed plausible
to a physicist in a time before the theory of relativity had been
published (but after the Michelson-Morley experiment had been done).



Nobody has a computer then. Today we can calculate what the result
would be if a bullet stream from a moving machine gun moving in an
elliptical
orbit that obeyed Kepler's laws were to arrive at any distance.
The intensity of arriving bullets (grey line) looks like this.


http://www.androc1es.pwp.blueyonder....r/V1493Aql.JPG

If you examine the image closely, you'll see a crossover where the
faster bullets
has caught up with and passed the slower bullets.
That is a simple distance / time plot, distance vertical and time
horizontal.
What you would see is a sudden increase in the rate of arrival of
bullets,
then a second maximum, eventually tailing off.
A star in elliptical orbit would do the same thing.
Androcles.






What does this have to do with the comment you were responding to?
Either you have a complete theory of electromagnetism, which can make
correct predictions about all the experiments in classical
electromagnetism that have been done to date (which Maxwell's laws can
do), or you don't. And I'm pretty sure you don't.



Guessing again, are you not?


Sure, but I'd bet $100 that you don't have a complete set of equations
for predicting the dynamics of an arbitrary system of charges, with the
theory making the same predictions as Maxwell's laws for every
experimental setup which has been tested and found to agree with these
predictions. Will I have to pay up?





So why would you expect physicists to abandon Maxwell's laws in favor
of your ideas?



You did not address the point I made. How can you expect to know
what a physicist will accept without being aware if what I have said?


You either have a complete set of equations which can make predictions
about arbitrary systems of charges, or you just have a toy model which
you are applying to a particular case (a star in an elliptical orbit
emitting light waves in our direction). I read what you wrote, and it
only suggested the latter.

Jesse

"Jesse Mazer" wrote in message
...


Androcles wrote:

"Jesse Mazer" wrote in message
...

Androcles wrote:


"Jesse Mazer" wrote in message
...



Of course, before Einstein physicists didn't think Maxwell's laws
would be correct in every observer's reference frame--they thought
they would only hold exactly in the rest frame of the aether. They
would have believed that to state the laws of electromagnetism in a
way that would hold in all frames, you'd have to replace every x in
Maxwell's laws with (x - v*t), where v represents the observer's
velocity relative to the rest frame of the aether...any derivatives
of x would have to be replaced in the same way, like replacing
dx/dt with (dx/dt - v). This would give a new set of
electromagnetic laws which would be Galilei-invariant, and which
would reduce to Maxwell's laws in the case where v=0.

But a prediction of this Galilei-invariant analogue of Maxwell's
laws would be that for an observer in motion relative to the
aether, light will be observed to move at different speeds in
different directions, relative to himself. Unfortunately this was
not supported by the Michelson-Morley experiment.


The speed of light in diamond, water, air, any transparent medium is
constant with respect to the medium. MMX fails to support aether.
In MMX, the medium is air. It is as simple as that.


What do you mean "the medium is air"?


I mean that air was used as a medium for light,
by Michelson, in his interferometer, of course.
He did not perform the experiment in an evacuated chamber, on the
surface
of the moon, or aboard the ISS.




My point was that when waves are considered as a vibration in a
medium, like sound waves, the speed of any wave will be constant with
respect to the rest frame of the medium.


Your points are invariance, x-vt, Maxwell's laws, derivatives, aether
and
anything else you can mention hoping to cover the issue, but you
omitted
to say anything about the physical medium used and asked me what I
meant by it, so clearly it was NOT your point, it is MY point.

Recall that Einstein's second postulate is
"light is always propagated in empty space with a definite velocity c
which is independent of the state of motion of the emitting body".


Maxwell's laws also say that light's velocity is independent of the
state of motion of the emitting body,

For light in a medium. Maxwell believed in aether.


regardless of whether you have the relativistic understanding of
these laws (that they hold in all reference frames)

Michelson was intending to use doppler shift to measure the
the speed of light in the aether as the Earth flew through it. He was
certainly NOT claiming the speed of light was invariant. Neither was
Maxwell. Both believed time and distance are invariant, as indeed
they are.

or the pre-relativistic understanding of them (that they only hold in
one preferred frame, and in other frames the velocity of light would
be c+v in one direction and c-v in the other).

Both are wrong. The speed of light is source dependent in a vacuum,
and medium dependent when passing though a medium. The medium
becomes the new source, of course.




All speeds are relative to something.
When requesting a drink on a plane, my speed relative to the flight
attendant is also zero, even though travelling at 500 mph ground speed
and 250 mph by the air speed indicator.
The speed of light inside a plane, as with the speed of sound, is
relative.


That's because the plane carries its own little pocket of air with it,

So does MMX, so we can put that one to bed. MMX has nothing
whatever to do with Einstein's relativity. Have it struck from the
FAQ's, which are a biased and prejudiced sham, a disgrace to science.



so inside the plane you are at rest relative the local medium. If you
were skydiving and you tried to yell out to a fellow skydiver below
you, if you were both moving down at velocity v relative to the rest
frame of the atmosphere, then you would observe the soundwaves to be
going at s-v downward and s+v upwards, in your reference frame (s is
the speed of sound in the air's rest frame).

There were some attempts to explain the MMX by suggesting the earth
dragged a pocket of aether along with it as it orbited, just like a
plane carries a pocket of air, so people on earth were always at rest
in relation to the local aether.

There is no doppler shift to observe for either sound or light, nor do
I expect there to be.
MMX is an attempt to measure doppler shift. It failed.


No it isn't.
Yes it is.
The anticipated fringes are a beat frequency between the light doppler-
shifted in the direction of motion through the aether and light that is
transverse to it.


Doppler shift is only about change in frequency--you tried to prove
otherwise with an equation, but you didn't answer where you got the
equation when I asked (it was not the same as the doppler shift
equation I found when I looked it up), and I also didn't understand
how you were trying to use it to prove that the frequency wouldn't
change.

Would you agree that if I hear the whistle of a train coming towards
me, the pitch will be changed but the speed of the sound wave will not
be an different than the speed of a sound wave from a train standing
still?

Would you agree that if I hear the whistle of a stationary train
I'm driving toward, the pitch will be changed and the speed of the sound
wave will be very different than the speed of a sound wave from a train
standing still in my frame of reference?
Doppler's equation is
c+u
f' = f -------------
c+v
u the speed of my car, v the speed of the train, c the speed of sound in
the
medium.
Thus I can drive alongside the train alongs Route 65 approaching
Pittsburgh at 45 mph and perceive no shift as the train approaches the
crossing at Leetsdale, where I'll have to wait as I have done on
numerous
occasions.


There is no aether.
Shall I then say, the speed of sound is invariant because there is no
doppler shift aboard a plane?


Again, the explanation for that is just that the plane carries its own
pocket of air along with it, so you are still at rest relative to the
medium of soundwaves inside the plane.

There is no doppler shift for the light, either. Same reason.
Hence the speed of light is not invariant.






In any case, if you're just saying MMX is consistent with your idea
that the speed of light depends on the source velocity, I wouldn't
disagree,


Good. So why complicate matters?
"Everything should be made as simple as possible, but not
simpler." -Einstein.
Pity he didn't take his own advice.


but the point is that Maxwell's laws are *not* consistent with that
idea,


"It is known that Maxwell's electrodynamics--as usually understood
at the present time--when applied to moving bodies, leads to
asymmetries
which do not appear to be inherent in the phenomena." - Einstein.

"It is known that Einstein's electrodynamics--as usually understood
at the present time--when applied to moving bodies, leads to
asymmetries
which do not appear to be inherent in the phenomena" - Androcles.

So, something is wrong with Maxwell's equations that Einstein attempts
to fix, but in doing so introduces absurdities that are obvious to the
meanest intelligence, but accepted by "theoretical" physicists. Wrong
fix.
Maxwell was an aetherialist, and there is no aether.


Maxwell's laws are just equations for predicting the dynamical
behavior of a system of charges.

I have no objection to dB/dt = E or dE/dt = B.
The solutions are E.sin(omega t) and B.cos(omega t)
Once it is realized that an electric field can exist in a vacuum, a
magnetic
field can exist in a vacuum, and that sin^2 + cos^2 = 1, that being
constant energy and conserved, there is no requirement for c at all.
The photon exists and propagates with whatever velocity was imparted
to it.

It is totally irrelevant whether you interpret them in terms of aether
or not.

We don't need any aether. The electric field collapses and creates the
magnetic field, and the two leapfrog one over the other.
http://www.androc1es.pwp.blueyonder.co.uk/Photon.jpg


Again, when Einstein said "as usually understood at the present time",
he was referring to the idea that Maxwell's laws would only hold in a
single preferred reference frame (which most physicists imagined to be
the rest frame of the aether, but again, this is irrelevant) and in
other frames they'd have to be modified using the Galilei
transformation (substituting x + vt for x in the equations).




whether you assume Maxwell's laws hold in all frames (as in
relativity) or you assume they only hold in a particular frame, and
you have to do a Galilei transform on them to describe E&M in other
frames (as physicists assumed would be true before relativity).
Maxwell's laws are very successful at predicting all sorts of
electromagnetic behavior, so if you want to throw them out, you'd
better have a good alternative which can make most of the same
predictions.


I do.


OK, present the complete equations of your theory,

I don't have a theory. All theories are the work of others.
I have good alternatives which make the same predictions, but I lay
no claim to ownership. Newton said time is invariant. I agree
with him. Distances are invariant too. Speed is not invariant, speed
is relative. Galileo said so.


that I can use to
calculate the dynamics of an arbitrary system of moving charges.
Otherwise no, you don't.






but this would be false according to both Maxwell's laws *and* the
modified Galilei-invariant analogue of Maxwell's laws (which says
that light waves, like sound waves, always travel at the same speed
in the rest frame of the aether/air,


Forget aether, it doesn't exist. Air does, though. So does water.
A stick passing through the air-water interface appears bent.
That is empirical evidence that the speed of light is medium
dependent.


I don't think aether exists either, I was just describing what would
be predicted by the modified Galilei-invariant analogue of Maxwell's
laws which physicists believed in before relativity.


What Galilean invariance are you talking about?
Time, length and mass are invariant. length/time is not, time/mass is
not,
mass/length is not.


I already explained Galilean invariance in a previous post. Here's the
definition of a Galilei transformation again, followed by an
explanation of what it means for a set of laws to be
Galilei-invariant:

x'=x - vt
y'=y
z'=z
t'=t

Yes, ok, t is invariant, distance is invariant. You missed out mass,
though.

x=x' + vt'
y=y'
z=z'
t=t'

To say a certain physical equation is "Galilei-invariant" just means
the
form of the equation is unchanged if you make these substitutions.
For
example, suppose at time t you have a mass m1 at position (x1, y1,
z1)
and another mass m2 at position (x2, y2, z2) in your reference frame.
Then the Newtonian equation for the gravitational force between them
would be:

F = Gm1m2/[(x1 - x2)2 + (y1 - y2)2 + (z1 - z2)2]

Now, suppose we want to transform into a new coordinate system moving
at
velocity v with respect to the first one. In this coordinate system,
at
time t' the mass m1 has coordinates (x1', y1', z1') and the mass m2
has
coordinates (x2', y2', z2'). Using the Galilei transformations, we
can
figure how the force would look in this new coordinate system, by
substituting in x1 = x1' + vt', x2 = x2' + vt', y1 = y1', y2 = y2',
and
so forth. With these substitutions, the above equation becomes:

F = Gm1m2/[(x1' + vt' - (x2' + vt'))2 + (y1' - y2')2 + (z1' - z2')2]

and you can see that this simplifies to:

F = Gm1m2/[(x1' - x2')2 + (y1' - y2')2 + (z1' - z2')2]

In other words, the equation has exactly the same form in both
coordinate systems. This is what it means to be "Galilei invariant".
More generally, if you have *any* physical equation which computes
some
quantity (say, force) as a function of various space and time
coordinates, like f(x,y,z,t) [of course it may have more than one of
each coordinate, like the x1 and x2 above, and it may be a function
of
additional variables as well, like m1 and m2 above] then for this
equation to be "Galilei invariant", it must satisfy:
f(x'+vt',y',z',t') = f(x',y',z',t')


And to clear up a point you misunderstood earlier, the statement "f(x'
+ vt',y',z',t') = f(x',y',z',t')" must hold true for *all* values of v
in order for a given physics equation to have the property of "Galilei
invariance".

I have no idea what your function f is, but the arguments (x' + vt') and
(x') do not appear to be relevant. The remaining arguments being
identical,
I expect equality.

Maxwell's laws are not Galilei-invariant, but if you take the
equations of Maxwell's laws and replace x with x + vt, and dx/dt with
dx/dt + v (I got the sign wrong in the other post), then this modified
version of Maxwell's laws should have the property of
Galilei-invariance (for example, since the ordinary version of
Maxwell's laws predicts that dx/dt = c for an electromagnetic wave,
these modified laws would say that dx/dt + v = c, which means that the
velocity of the wave will be dx/dt = c - v, if you are in a frame
moving at v with respect to the preferred frame where Maxwell's laws
hold exactly). As I said before, the common belief about Maxwell's
laws before Einstein was that they would only hold in a preferred
frame, so if you jumped to a different frame which was related to the
preferred frame by a certain Galilei transformation, you'd have to use
these modified Maxwell's equations to make predictions about
electromagnetic behavior in your frame.

The common belief before Einstein was correct, then, although I fail
to see how dB/dt = E is frame dependent.





regardless of the velocity of their source).


Source dependency only applies in the absence of a medium. There is
no aether.


Both Maxwell's laws and the Galilei-invariant analogue of Maxwell's
laws predict that the velocity of a light wave is independent of the
velocity of the source.


You have yet to show what you mean by "Galilei-invariant analogue "


I have explained several times that if you substitute x + vt for x in
Maxwell's equations, and dx/dt + v for dx/dt (I actually said x - vt
and dx/dt - v earlier, but that was a sign mistake), you should get an
analogue of Maxwell's laws that is Galilei-invariant.

Here' a little something to think on.
Imagine a standing wave in a long tank of water.
\/\/\/\/\/\/\/\/\/\/\ t=0
/\/\/\/\/\/\/\/\/\/\/ t=1

It has a frequency 1 Hz and wavelength 1 metre, but it is a
standing wave.
Now imagine you are alongside a crest at t0 and intend to
walk the length of the tank to count crests and divide the
tank length (10 metres) by the count to get the wavelength.
/\ /\
/ \ / \
/ x \ / y \
/ \/ \

You walk to the next crest at y, but guess what? It isn't there.
It became a trough while you moved.
\ /\ /\
\ x / \ y / \
\ / \ / \
\/ \/ \

So you don't count it. When you get to the end of the tank
your wavelength will be 10 metres /5(counts) = 2 metres.
You check your watch and find that 10 seconds have elapsed.
So the frequency is 5/10 = 0.5 Hz.
Ok, so c = wf = 2 * 0.5 = 1. The speed of the wave going past you
is the same as the speed of you going past the tank.
You stroll down to the middle of the tank and tell me about it.
I count crests right in front of me, 1 a second. I get out tape
measure, stretch it across the tank, 10 metres. I stand back and
count the crests, 10 of them. I DO agree with your speed. I do
NOT agree with your frequency and I do NOT agree with your
wavelength.
Henri arrives, and says "What speed? It's a standing wave!"

Homework:
Prove that the speed of all waves, not just light, is invariant.






This can be proved mathematically just by looking at the equations of
the laws, it's irrelevant whether you conceive of these laws as
describing "vibrations in aether" or if you conceive of them in a
different way.


I conceive of them a different way, and you will not mathematically
disprove that dfferent way.


You can't mathematically prove or disprove a physical theory, only
that the theory makes certain predictions, which could be right or
wrong.

Maybe not, but Occam's Razor can shave mightly close.


Do you agree that Maxwell's laws predict, rightly or wrongly, that the
velocity of an electromagnetic wave such as light is always
independent of the velocity of the source, regardless of whether you
take the relativistic view that Maxwell's laws work in every frame, or
the pre-relativistic view that they only hold exactly in a certain
preferred frame, and that in other frames the velocity of light would
be c+v in one direction and c-v in the other?

I don't know what you mean by laws. The speed of light in a medium
is medium dependent and that takes care of MMX. The speed of
light in a vacuum (or as Einstein would say "empty space") is source
dependent, as variable stars do not intrinsically vary. Time (certainly
for Maxwell) is invariant. So is distance. Those are the laws.


So unless he can find a theory that gives correct predictions for
all the various experiments in classical electromagnetism, and yet
does not have the feature that the velocity of light is independent
of the source velocity, then his ideas wouldn't even have seemed
plausible to a physicist in a time before the theory of relativity
had been published (but after the Michelson-Morley experiment had
been done).


Nobody has a computer then. Today we can calculate what the result
would be if a bullet stream from a moving machine gun moving in an
elliptical
orbit that obeyed Kepler's laws were to arrive at any distance.
The intensity of arriving bullets (grey line) looks like this.


http://www.androc1es.pwp.blueyonder....r/V1493Aql.JPG

If you examine the image closely, you'll see a crossover where the
faster bullets
has caught up with and passed the slower bullets.
That is a simple distance / time plot, distance vertical and time
horizontal.
What you would see is a sudden increase in the rate of arrival of
bullets,
then a second maximum, eventually tailing off.
A star in elliptical orbit would do the same thing.
Androcles.





What does this have to do with the comment you were responding to?
Either you have a complete theory of electromagnetism, which can make
correct predictions about all the experiments in classical
electromagnetism that have been done to date (which Maxwell's laws
can do), or you don't. And I'm pretty sure you don't.


Guessing again, are you not?


Sure, but I'd bet $100 that you don't have a complete set of equations
for predicting the dynamics of an arbitrary system of charges, with
the theory making the same predictions as Maxwell's laws for every
experimental setup which has been tested and found to agree with these
predictions. Will I have to pay up?

No. I do not have all the answers and never claimed to. I certainly do
not
have a complete set of equations, it took me ages to understand
Kepler's
equation M = E-e.sin(E). However, I do claim that Einstein's equation,
½[tau0+tau2] = tau1
is fallacious and nonsensical. The ½ is meaningless drivel.


So why would you expect physicists to abandon Maxwell's laws in favor
of your ideas?


You did not address the point I made. How can you expect to know
what a physicist will accept without being aware if what I have said?


You either have a complete set of equations which can make predictions
about arbitrary systems of charges, or you just have a toy model which
you are applying to a particular case (a star in an elliptical orbit
emitting light waves in our direction). I read what you wrote, and it
only suggested the latter.

It applies to flare stars, cepheids, eclipsing variables and recurrent
novae.
Only the orbital parameters and distance change.
Androcles.

On Tue, 11 Jan 2005, Androcles wrote:

"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:
"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:

The speed of light in diamond, water, air, any transparent medium
is
constant with respect to the medium.

Loosely phrased, and wrong. The phase speed of light of a given
frequency
in diamond, water, air, any stationary medium, is constant with
respect to
the stationary medium.

Good enough to explain MMX.

So is SR, so is a fully-dragged Galilean ether, so is a Lorentz
ruler-shrinking clock-slowing ether, and so is just about any emission
theory.

Ordinarily, it would be somewhat pedantic point, but empirical
observations of the speed of light in a moving medium were
historically
important, and continue to be theoretically important, in chosing
which of
the above explanations of MMX could be correct. In the context of
using an
emission theory to explain MMX, it's a worthwhile point.

SR isn't good enough, and doesn't.

That's simply wrong. Pretty much any theory that doesn't assume that there
is a medium in which the electromagnetic waves move that is in motion wrt
the apparatus explains MMX.

SR doesn't assume there is any medium. Emission theories don't assume
there is any medium. There explanation is the same.

Hint: the fringe shift is a beat frequency.

Given that the source in not in motion relative to the rest of the
apparatus, I'm not aware of any post-1800 theory that was ever a serious
contender for explaining electromagnetism or light that would have
predicted any frequency shifts. To get a beat frequency, you need to have
two different frequencies present. With a monochromatic source, to get two
different frequencies, you need a frequency shift.

If your above incorrect statements are simply honest mistakes, I assume
that you'll be willing to discuss some physics related to these.

--
Timo Nieminen - Home page: http://www.physics.uq.edu.au/people/nieminen/
Shrine to Spirits: http://www.users.bigpond.com/timo_nieminen/spirits.html

"Timo Nieminen" wrote in message
news:Pine.LNX.4.50.0501120833570.8834-100000@localhost...
On Tue, 11 Jan 2005, Androcles wrote:

"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:
"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:

The speed of light in diamond, water, air, any transparent
medium
is
constant with respect to the medium.

Loosely phrased, and wrong. The phase speed of light of a given
frequency
in diamond, water, air, any stationary medium, is constant with
respect to
the stationary medium.

Good enough to explain MMX.

So is SR, so is a fully-dragged Galilean ether, so is a Lorentz
ruler-shrinking clock-slowing ether, and so is just about any
emission
theory.

Ordinarily, it would be somewhat pedantic point, but empirical
observations of the speed of light in a moving medium were
historically
important, and continue to be theoretically important, in chosing
which of
the above explanations of MMX could be correct. In the context of
using an
emission theory to explain MMX, it's a worthwhile point.

SR isn't good enough, and doesn't.

That's simply wrong.

SR isn't good enough, and doesn't.

Androcles.

On Wed, 12 Jan 2005, Androcles wrote:

"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:

"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:
"Timo Nieminen" wrote:
On Tue, 11 Jan 2005, Androcles wrote:

The speed of light in diamond, water, air, any transparent
medium
is
constant with respect to the medium.

Loosely phrased, and wrong. The phase speed of light of a given
frequency
in diamond, water, air, any stationary medium, is constant with
respect to
the stationary medium.

Good enough to explain MMX.

So is SR, so is a fully-dragged Galilean ether, so is a Lorentz
ruler-shrinking clock-slowing ether, and so is just about any
emission
th