Re: Tom Van Flandern and Newtonian Gravity
From: Gerald Lasser (antispam_at_nospam-me.com)
Date: 08/19/04
- Next message: Albert: "Re: The Emptiness of Theology"
- Previous message: Albert: "Re: The Emptiness of Theology"
- In reply to: Tom Van Flandern: "Re: Tom Van Flandern and Newtonian Gravity"
- Next in thread: Eugene: "Re: Tom Van Flandern and Newtonian Gravity"
- Reply: Eugene: "Re: Tom Van Flandern and Newtonian Gravity"
- Messages sorted by: [ date ] [ thread ]
Date: Thu, 19 Aug 2004 20:19:44 GMT
On Thu, 19 Aug 2004 "Tom Van Flandern" wrote:
> I understand your point about electrostatics. But I do not agree
> with your inference that "propagation speed has no significance"
> in electrostatics...
To say "propagation speed has no significance in electrostatics" is
not to say there is no propagation speed - in fact, I've already shown
you that the electrostatic force DOES have a finite propagation speed,
namely c - but this propagation speed has no empirical significance in
the absence of any motions, because in such a context we can equally
well imagine any propagation speed we like, without fear of being
contradicted by observations. Only when things change with time can
we observe the effects of a specific propagation speed. Once we have
determined this speed by observing the time-dependent responses
of objects, and once we have found that this propagation speed is the
same regardless of how slowly things are moving, then we can hardly
avoid the conclusion that the propagation speed is the same even when
things are not moving at all (when the propagation speed is, strictly
speaking, unobservable).
Since confusion can arise over the significance of source motions
versus motions of test particles, I gave you a concrete physical
example of the effect of finite propagation speed, with two initially
stationary charged particles separated by a distance D, and I stated
that Maxwell's equations imply that if we abruptly change the position
of one of the particles, the other experiences no change until a time
D/c later. You agreed (then) that the length of time before the
second particle experiences a change is a valid measure of the
propagation delay of the electric force, but you disagreed that
Maxwell's equations predict this delay will be D/c. I then explained
in detail why, according to Maxwell's equations, the delay is D/c, so
now you're trying to discount this. I don't think you're being
intellectually honest.
>>> [tvf]: If you can show me a propagation delay of D/c for forces in
>the existing Maxwell equations (for a target body/charge with a relative
>motion), my whole argument fails.
>> [Lasser]: Done.
> Please try one more time, respecting the terms of the challenge.
I don't think you are being honest with yourself... let alone with me.
I gave a clear and precise explanation of the "propagation delay of
D/c for forces in the existing Maxwell equations (for a target
body/charge with a relative motion)", and now it seems to me you are
just covering your ears and making loud whooping noises to avoid
hearing it. Please try one more time to search your soul for a shred
of intellectual honesty and admit that Maxwell's equations imply a
propagation delay of D/c for the electric force.
> To keep things as simple as possible, I want to stick with the non-
>time-varying potential field from a single static (non-moving) charge,
>and use an electric force sensor moving uniformly through the field
>without changing the field.
This confirms that your entire position is based on the erroneous
application of electrostatic concepts and formulas to electrodynamics.
The full time-dependent equation for the electric field (with which
you claim to agree) clearly contains a propagation speed of c. If you
cannot acknowledge this plain fact, you can hardly expect to be
regarded as a rational person.
What you seem to want to discuss now is not a propagation delay in the
potential field, per se, but a velocity-dependent potential. This is
a different concept altogether. A velocity-dependent potential may or
may not have a propagation delay. You are basically claiming (now)
that the electric potential is velocity-dependent, in the sense that
the force on a test particle depends not only on its position but also
on its velocity. You relate this to a finite propagation speed in
your own mind because you ensivion the velocity dependence as similar
to a particle flying through a radiation field, and encountering a
transverse drag as well as a force in the direction of the radiation.
The problem is that it's well known the electric force is not the same
as a radiation pressure.
You seem to be commited to a particular model of force conveyance
(such as a radiation field) that implies a stationary central field
would impart some tangential momentum to a tangentially moving test
particle. However, that type of force model is both logically and
empirically untenable, whereas there are other models of force
conveyance that do NOT entail such tangential drag, and that are
perfectly logical and consistent with all empirical evidence, as well
as locality, causality, momentum conservation laws, etc. The fact
that you are unacquainted with these models is not the fault of the
models.
> I stressed several times before that we are not interested
>here in retardation in the potential field....
You have indeed stated this, and it's been explained to you repeatedly
and in detail why your statement is insane. A force potential is
DEFINED as a function whose partial derivatives equal the components
of the force. Your assertion that the force can change before the
force potential changes is therefore insane. Do you understand this?
A given potential function at a given point cannot have two different
derivatives. If you can't bring yourself to acknowledge this plain
fact, then you can hardly expect to be regarded as a rational person.
The main thing you need to reconcile yourself to is the D/c delay in
the propagation of the electric force, as is plainly required by
Maxwell's equations (not to mention observed continuously in daily
life). If your position is that the electric force experienced by the
second particle actually responds with a delay many orders of
magnitude less than D/c, then you are in direct conflict with
observation. The propagation delay in the electric (as well as the
magnetic) field is an inherent part of how electromagnetism works.
The world would not look anything like it does if this delay were not
present - in fact, nothing would LOOK like anything, because there
would be no light. So if you want to claim that there is some OTHER
delay, in addition to the delay implied by Maxwell's equations, then
you are really claiming TWO separate delays. Maxwell's delay is
necessary and sufficient to account for all the relevant phenomena,
(and by the way it is also sufficient to ensure that classical
electrodynamics satisfies locality, causality, conservation of energy
and momentum, etc.). From what I can tell, your hypothesis of a
mysterious and unobservable second delay is motivated solely by your
lack of understanding of present theory.
Good luck in your studies.
- Next message: Albert: "Re: The Emptiness of Theology"
- Previous message: Albert: "Re: The Emptiness of Theology"
- In reply to: Tom Van Flandern: "Re: Tom Van Flandern and Newtonian Gravity"
- Next in thread: Eugene: "Re: Tom Van Flandern and Newtonian Gravity"
- Reply: Eugene: "Re: Tom Van Flandern and Newtonian Gravity"
- Messages sorted by: [ date ] [ thread ]
Relevant Pages
|
