Re: Tom Van Flandern and Newtonian Gravity
From: Gerald Lasser (antispam_at_nospam.com)
Date: 09/21/04
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Date: Tue, 21 Sep 2004 02:20:30 GMT
On Mon, 20 Sep 2004 "Tom Van Flandern" wrote:
> ...You are saying that the observable results will be different
> depending on whether the charge is at rest and the sensor moving,
> or the sensor is at rest and the charge moving.
No, I said the equations of electrostatics are not applicable to
coordinate systems with respect to which the charges are moving -
a plain statement of fact. Maxwell's equations are relativistic, but
the equations of electrostatics (e.g., Coulomb's force law) are not,
because they omit all the time-dependent terms. Coulomb's force law
applies only in terms of coordinates with respect to which all the
charges involved are at rest, so nothing depends on time.
>Electric forces are not a wave phenomenon, and therefore have no
>natural nearfield/farfield distinction.
Non-sequitur. Again, the far field is a synonym for the radiation
field, i.e., the region of predominantly wave-like propagation,
whereas the near field is predominantly NON-wave-like propagation.
All these are fluctuations in the electromagnetic field in accord with
Maxwell's equations. All propagate at c.
>> According to those equations (with which you claim to agree), the
>> fields at the other particle are totally unaffected until a time D/c
>> after the first particle was moved.
>Why do we regress on this point with every message?
Because it's an excellent demonstration of the fact that all your
ideas are erroneous. According to you, the fields at the other
particle would change almost instantly when the first particle is
moved, but Maxwell's equations (with which you claim to agree) say
the fields at the other particle will be totally unaffected until a
time D/c later. Commonplace observations show that this D/c delay
actually occurs. Therefore, your position is both logically
self-contradictory and empirically falsified.
> In point of fact, lightwaves of any wavelength carry no charge and no
> magnetic field.
You are very confused. Maxwell's equations (with which you claim to
agree) state that a changing electric field produces a magnetic field
and vice versa, and this leads to traveling waves of transverse
oscilating electric and magnetic fields moving at the speed c.
Electromagnetic waves are routinely produced by oscillating electric
and magnetic fields, and the electromagnetic nature of these waves was
confirmed over a century ago by showing how we can re-orient the
polarization of EM waves by passing them near an electromagnet, all
precisely in accord with the predictions of Maxwell's equations.
And now you announce that lightwaves carry no magnetic field! You also
say they "carry no charge", which of course is ridiculous; no one ever
said they carry charge. They consist of oscilating electric and
magnetic FIELDS (not charges).
>The forces they apply are purely radiation pressure, not electric or
>magnetic forces.
Are you actually saying you believe radios and televisions work by
radiation pressure? Is THAT what you believe causes the electrons in
the receiving antenna to oscilate? It seems to me you know nothing at
all about electromagnetism. Did you never adjust a rabbit ear antenna
on an old TV set? Did you never notice that the reception was best
when you aligned the antenna perpendicular to the direction of the
broadcasting antenna, and then rotated it about that axis to line up
with the polarity? If the signal consisted of radiation pressure, this
would be the worst possible orientation for picking up a signal (and
you wouldn't be able to account for the polarity effect at all).
So, according to you, electromagnetic waves do NOT consist of
oscillating electric and magnetic fields? Is that right? And STILL you
claim to agree with Maxwell's equations?
>And no experiment has ever measured an electric force propagating
>as slowly as speed c. But it is easy to prove me wrong by citing one.
You mean one MORE? I've already pointed out that near field radar
falsifies your silly claims. You seem to think this involves some kind
of exotic "experiment". This is just commonplace stuff.
Here's another empirical confirmation for you to ignore: Michelson and
Morley, who showed that the equiibrium configurations of matter are
Lorentz covariant, which can only be true if all the forces
responsible for the configurations of matter are Lorentz covariant.
The electric field surrounding a charge MUST be contracted into an
elipsoid in the direction of motion with respect to a coordinate
system in which it is in motion... and the field does this because of
the retarded potential, i.e., the D/c delay in the propagation of the
electric force. If the electric force was not delayed by D/c, the
electric field would not be Lorentz covariant, so all the experiments
proving Lorentz covariance prove that the electric force has a D/c
delay.
> ... the speed of those waves has no relationship whatever to the
> speed of the force that displaced the body.
You're confused. The "displaced body", like the moved charge in my
first example and the piston in my second example, is stipulated to
be displaced by direct manipulation, so there is no propagation
involved. The subject at hand is how the effect of this given
displacement propagates to the OTHER body. In the case of the piston
and cylinder, the force propagates at the speed of sound in the gas.
In the case of the charges particles the force propagates at c in the
electric field.
>> [Lasser]: Now suppose a particle is moving through the point (2,7,-4)
>> with the speed v in the positive x direction. What now is the gradient
>> of f at the point (2,7,-4)?
> It is the same.
Right. Now let's get down to business: What is the gradient of f with
respect to the rest frame inertial coordinates of the moving particle?
>It is still a static field with a fixed value at every fixed point in the
>source's coordinate frame. But it must continually regenerate to
>maintain that static situation...
If you apply a static force to the ceiling of your room with a
broom handle, there is no "continual regeneration". The broom
is in a static equilibrium configuration. If you increase the force on
your end of the broom, the force on the ceiling will not change until
L/V later, where L is the length of the broom and V is the speed of
sound in the broom material.
There is more than one way of modeling electric and magnetic forces,
but no matter how you choose to model them, if you want to be
empirically viable you need to have a D/c delay. The way Maxwell
conceived of it is that a static electric field is an equilibrium
configuration of its different parts, each of which has its own energy
and momenta and inertia. When some boundary condition changes,
the field re-configures (just like the broom handle). Changes in the
field propagate at the speed c. (Mind you, Maxwell's conception of
electromagnetism is not the best, but if you could at least bring
yourself up to his level, you would have made HUGE progress. He at
least had a theory that was more or less consistent with empirical
facts.)
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