Franz Heymann wrote:

"Androcles" wrote in message
. uk...

[snip]



Which is logically impossible. So forget Lorentz invariance, it is
sci-fi.



I see you have never tried to see if Maxwell's equations obey Lorentz
or Galilean invariance.
Have a shot at it if you want to give yourself an unpleasant surprise.


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

Jesse