There is nothing in Newton's laws (to which TVF adhers to) that
assigns a speed to force. In NM, force and acceleration are considered
instantenuous cause-effect relationship - or to be more precise, it is
a streched causality.

Only crackpots believe force is a real thing that has a speed, so much
for potential.

As many published experiments have demonstrated, gravitational forces
can not possibly
propagate at c. I consider this as a scientific fact, indeed.

There is no propagation of gravitational forces in NM. The effect is
instantenuous,it's called action_at_a_distance. Where in the world and
from which crackpot did you hear that? Central forces in NM must apply
instantenuously and induce a centripetal acceleration to a body
instantenuously. There is no such thing as "speed of gravity" in
Newtonian mechanics.

In GR, there is also no such thing as "speed of gravity" because in GR
there is no gravity. Gravitational effects - something not equivalent
to gravity in the usual sense - are caused by spacetime curvature,
i.e. GR is a purely geometrical theory of gravitational effects -- and
dynamical motion in general.

Tom Van Flandern <to...@metaresearch.org> wrote:

Playing with the definitions of words does no one trying to follow this
discussion any good. You avoid defining "gravitational influences" and just
cite a reference. However, no one is disputing that changes in gravitational
potential (the subject of the field equations) propagate at the speed of
light, c. I am always careful to state that "the speed of gravity" measured
by the six available experiments always means the 3-space propagation speed
of gravitational force, and has nothing to do with changes in gravitational
potential.

That's garbage, Tom.

I used the term "gravitational influence" simply to avoid getting into a
pointless debate about whether gravity in GR is "really" or force or not.
If you would go and read Low's paper, you would see that he is clearly
contradicting your claim.

What Low shows is the following:

Let R be an arbitrary region in space (at a fixed time, say t=0) containing
some sources of gravitation. Let p be a point outside R, at a distance d
from R -- that is, for which the closest point in R is a distance d away.

At time t=0, change conditions in R any way you want -- move the masses
around, add more masses, take some away, anything at all, as long as you
don't change anything outside R. What happens at p? Low shows that it
is a clear, unequivocal, unambiguous prediction of GR that nothing
whatsoever changes at p until a time d/c has passed.

To repeat: change the source of gravity in R any way you want. According
to GR, nothing at all happens at a point p outside R until the time for a
light signal to reach p from R has passed. By any sensible definition of
"speed" I can imagine, that means that gravity propagates at the speed
of light.

If you accept this, then we are merely arguing over semantics (although I
would add that your definition of "speed of gravity" must be truly bizarre).
If you don't accept this, then you don't accept "the mathematics of GR."
Period.

Tom Van Flandern <to...@metaresearch.org> wrote:

[...]

[Carlip]: There is a rigorous proof, using the full Einstein field
equations (and not just a low-order approximation that can hide the
underlying structure), that gravitational influence propagates at the
speed of light
    Playing with the definitions of words does no one trying to follow this
discussion any good. You avoid defining "gravitational influences" and just
cite a reference.  However, no one is disputing that changes in gravitational
potential (the subject of the field equations) propagate at the speed of
light, c. I am always careful to state that "the speed of gravity" measured
by the six available experiments always means the 3-space propagation speed
of gravitational force, and has nothing to do with changes in gravitational
potential.

That's garbage, Tom.

I used the term "gravitational influence" simply to avoid getting into a
pointless debate about whether gravity in GR is "really" or force or not.

If you would go and read Low's paper, you would see that he is clearly
contradicting your claim.

What Low shows is the following:

Let R be an arbitrary region in space (at a fixed time, say t=0) containing
some sources of gravitation.  Let p be a point outside R, at a distance d
from R -- that is, for which the closest point in R is a distance d away.  

At time t=0, change conditions in R any way you want -- move the masses
around, add more masses, take some away, anything at all, as long as you
don't change anything outside R.  What happens at p?  Low shows that it
is a clear, unequivocal, unambiguous prediction of GR that nothing
whatsoever changes at p until a time d/c has passed.

To repeat: change the source of gravity in R any way you want.  According
to GR, nothing at all happens at a point p outside R until the time for a
light signal to reach p from R has passed.  By any sensible definition of
"speed" I can imagine, that means that gravity propagates at the speed
of light.

If you accept this, then we are merely arguing over semantics (although I
would add that your definition of "speed of gravity" must be truly bizarre).
If you don't accept this, then you don't accept "the mathematics of GR."
Period.

    Then in Ref. [3], Vigier and I carefully showed exactly where in GR the
switch is made from the speed of changes in gravitational potential (c) to
the propagation speed of gravitational force (infinity).

No, you don't.  You just demonstrate that you don't understand the math,
and that you don't know the difference between speed and direction.

[...]

[Carlip]: If you really "agree[d] with GR as a mathematical theory," the
argument would be over.
    Apparently, it would not, because I do agree with GR as a mathematical
theory, but have taken great pains to show (as others before me have done)
that the mathematical theory has more than one physical interpretation; and
that one of those interpretations (the "geometric") has now been falsified
in favor of another (the "field" interpretation). In short, GR as Einstein
taught it is just fine; but much of the post-Einstein evolution of GR has
been unproductive or outright wrong.

The issue has nothing to do with interpretation.  Go *read* Low's paper
(better yet -- read it and try to actually understand it).  The GR prediction
is unequivocal.

Steve Carlip

On Apr 18, 4:09 pm, carlip-nos...@physics.ucdavis.edu wrote:





Tom Van Flandern <to...@metaresearch.org> wrote:
    Playing with the definitions of words does no one trying to follow this
discussion any good. You avoid defining "gravitational influences" and just
cite a reference.  However, no one is disputing that changes in gravitational
potential (the subject of the field equations) propagate at the speed of
light, c. I am always careful to state that "the speed of gravity" measured
by the six available experiments always means the 3-space propagation speed
of gravitational force, and has nothing to do with changes in gravitational
potential.

That's garbage, Tom.

I used the term "gravitational influence" simply to avoid getting into a
pointless debate about whether gravity in GR is "really" or force or not..
If you would go and read Low's paper, you would see that he is clearly
contradicting your claim.

Low’s paper is full of handwaving.  Your proposal to nullify the speed
of gravity through aberration is even more faulty.  As a scientist,
how can you live with that?  Where is your ethics?





What Low shows is the following:

Let R be an arbitrary region in space (at a fixed time, say t=0) containing
some sources of gravitation.  Let p be a point outside R, at a distance d
from R -- that is, for which the closest point in R is a distance d away..

At time t=0, change conditions in R any way you want -- move the masses
around, add more masses, take some away, anything at all, as long as you
don't change anything outside R.  What happens at p?  Low shows that it
is a clear, unequivocal, unambiguous prediction of GR that nothing
whatsoever changes at p until a time d/c has passed.

To repeat: change the source of gravity in R any way you want.  According
to GR, nothing at all happens at a point p outside R until the time for a
light signal to reach p from R has passed.  By any sensible definition of
"speed" I can imagine, that means that gravity propagates at the speed
of light.

What you are saying is equally valid for anything including Newton’s
law of gravity.  It is an extension to the theory of non-causality.
shrug

If you accept this, then we are merely arguing over semantics (although I
would add that your definition of "speed of gravity" must be truly bizarre).
If you don't accept this, then you don't accept "the mathematics of GR."
Period.

If you accept there is no paradox in causality or in anything, a well
thought-out experiment would have no problem measuring the propagation
speed of gravitational effect.  As Dr. Van Flandern has pointed out,
all indicate this speed to be magnitudes higher.  If aberration does
not work for you, you must accept the experimental results which would
falsify GR in doing so.  If not, you have no right to claim yourself a
physicist.  <shrug

You are guilty of

**  MYSTICISM IS WIDSOM
**  FAITH IS THEORY- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

Tom Van Flandern <to...@metaresearch.org> wrote:

Playing with the definitions of words does no one trying to follow
this
discussion any good. You avoid defining "gravitational influences" and
just
cite a reference. However, no one is disputing that changes in
gravitational
potential (the subject of the field equations) propagate at the speed of
light, c.

Mystery of the day: what do Erica Gissa and Dirt of ther Mootel have
in common?

I mean besides being the same person.

Mike

That's garbage, Tom.

I used the term "gravitational influence" simply to avoid getting into a
pointless debate about whether gravity in GR is "really" or force or
not.

What Low shows is the following:

Let R be an arbitrary region in space (at a fixed time, say t=0)
containing some sources of gravitation. Let p be a point outside R, at
a distance d from R -- that is, for which the closest point in R is a
distance d away.

At time t=0, change conditions in R any way you want -- move the masses
around, add more masses, take some away, anything at all, as long as you
don't change anything outside R. What happens at p? Low shows that it
is a clear, unequivocal, unambiguous prediction of GR that nothing
whatsoever changes at p until a time d/c has passed.

To repeat: change the source of gravity in R any way you want.
According to GR, nothing at all happens at a point p outside R until the
time for a light signal to reach p from R has passed. By any sensible
definition of "speed" I can imagine, that means that gravity propagates
at the speed of light.

On Apr 19, 2:56 am, Mike <elea...@yahoo.gr> wrote:

[snip]

Mystery of the day: what do Erica Gissa and Dirt of ther Mootel have
in common?

I mean besides being the same person.

Another sad little person who doesn't understand the concept of
"headers" or how to use them.

I know what your response is going to be since I haven't seen you give
me another yet. Don't disappoint me.



Mike- Hide quoted text -

- Show quoted text -

On Apr 19, 8:24 am, Eric Gisse <jowr...@gmail.com> wrote:

On Apr 19, 2:56 am, Mike <elea...@yahoo.gr> wrote:

[snip]

Mystery of the day: what do Erica Gissa and Dirt of ther Mootel have
in common?

I mean besides being the same person.

Another sad little person who doesn't understand the concept of
"headers" or how to use them.

You know my response:

http://groups.google.gr/group/sci.physics.relativity/msg/dd24a9cdf16c...

You do not know the difference between an ODE and a mom-linear DE.
Moreover, that you think the free-fall equation is an ODE and that you
are " bored, walking to the toilet and peeing takes longer, and
required the same amount of mental horsepower."

I guess the only use of your mental horse power is for going to the
toilet. You said it, not me.

Mike



I know what your response is going to be since I haven't seen you give
me another yet. Don't disappoint me.

Mike- Hide quoted text -

- Show quoted text -- Hide quoted text -

- Show quoted text -

On Apr 18, 7:09 pm, carlip-nos...@physics.ucdavis.edu wrote:
Tom Van Flandern <to...@metaresearch.org> wrote:

[...]

[Carlip]: There is a rigorous proof, using the full Einstein field
equations (and not just a low-order approximation that can hide the
underlying structure), that gravitational influence propagates at the
speed of light
Playing with the definitions of words does no one trying to follow this
discussion any good. You avoid defining "gravitational influences" and just
cite a reference. However, no one is disputing that changes in gravitational
potential (the subject of the field equations) propagate at the speed of
light, c. I am always careful to state that "the speed of gravity" measured
by the six available experiments always means the 3-space propagation speed
of gravitational force, and has nothing to do with changes in gravitational
potential.

That's garbage, Tom.

I used the term "gravitational influence" simply to avoid getting into a
pointless debate about whether gravity in GR is "really" or force or not.

Gravity in GR in a form of "action", like in NM, does not exist.
Gravity in 3-D space + time, according to GR, is a perceived
phenomenon due to spacetime curvature. Notice the choice and ordering
of words. Gravity exists only in 3-D space and time. In GR, all there
is, is motion. Some of that motion, observers in 3-D space attribute
(right or wrongly) to grabitational forces.


If you would go and read Low's paper, you would see that he is clearly
contradicting your claim.

What Low shows is the following:

Let R be an arbitrary region in space (at a fixed time, say t=0) containing
some sources of gravitation. Let p be a point outside R, at a distance d
from R -- that is, for which the closest point in R is a distance d away.

At time t=0, change conditions in R any way you want -- move the masses
around, add more masses, take some away, anything at all, as long as you
don't change anything outside R. What happens at p? Low shows that it
is a clear, unequivocal, unambiguous prediction of GR that nothing
whatsoever changes at p until a time d/c has passed.

Correct. But you are talking in 4-D spacetime and the TFV team is
talking in 3-D space and time. You have no common ground. In the
former, it is d/c in the latter it is infinite.

[Wublee]: As you have correctly pointed out, LR does not manifest the
twin's paradox. However, it manifests the time dilation.

[Prime Mover]: As many published experiments have demonstrated,
gravitational forces cannot possibly propagate at c.

[Roberts]: True, _IF_AND_ONLY_IF_ one assumes that they propagate at all.

[Roberts]: In GR, the gravitational fields "here and now" do not propagate
from any source "over there". The fields "here and now" depend ONLY on the
fields "right near here a short time ago". So there is no need for
propagation from a source.

[Prime Mover]: As Tom Van Flandern has said, gravitational potential and
gravitational force are two distinct concepts and as such their speeds
does not have to be the same.

[Roberts]: I disagree. If "gravitational force" is to be the spatial
gradient of "gravitational potential", then they cannot have different
"propagation
speeds".

[Roberts]: When different people use different meanings of words, the
discussion can extend forever, as they talk right past each other. TVF
seems to be incapable of recognizing the puns he uses, even when pointed
out to him, so he repeats his same invalid claims.

[Prime Mover]: By the way, I read his papers on the subject and I saw no
apparent fraud, quite the contrary. They were fairly conducted, in my
opinion.

[Roberts]: Including his nonsense about Cydonia? Any "astronomer" who
writes such drivel is not trustworthy in my book. I don't mean the fact
that he is demonstrably wrong, for that can happen to anybody -- I mean
the fact that he claims "proof", and was as strident in claiming that as
he is
"speed of gravity".

[Albertito]: It is very easy to measure the gravitational force. You can
measure a force F, if you know the mass of the body and the acceleration
that force exerts on that body.

[Roberts]: That is a measurement of the acceleration, not the force.

[Tom VF]: no one is disputing that changes in gravitational potential
(the subject of the field equations) propagate at the speed of light, c.
I am always careful to state that "the speed of gravity" measured by the
six available experiments always means the 3-space propagation speed of
gravitational force, and has nothing to do with changes in gravitational
potential.

[Carlip, summarizing Low's paper]: change the source of gravity in R any
way you want. According to GR, nothing at all happens at a point p outside
R until the time for a light signal to reach p from R has passed. By any
sensible definition of "speed" I can imagine, that means that gravity
propagates at the speed of light.

[Carlip]: If you accept this, then we are merely arguing over semantics
...

[Carlip]: You just demonstrate that you don't understand the math,
and that you don't know the difference between speed and direction.

    If this force, or "gravitational influences" (your term), propagates
from source mass to target body at speed c, then we must use the retarded
gradient, which leads to wrong answers (outward spiraling orbits). If
force/gravitational influences propagate >> c, as in GR, then we get the
correct orbits.