On Apr 24, 6:30 am, "Juan R." González-Álvarez
juan...@VEcanonicalscience.com> wrote:
Ken S. Tucker wrote on Thu, 24 Apr 2008 04:33:53 -0700:

That rigorous mathematical and physical analysis has been confirmed
using a Liouville space extension of mechanics, and also extended to
gravity. One obtain basically the same conclusions: the speed of
gravity is not c.

Needs evidence.

You are not reading.

I already explained what are the physical and mathematical problems
with Low/Carlip analysis of gravitational interactions and how a more
*general* and *rigorous* model do *not* support their claims about
speed of gravity.

My own independent calculations support Low/Carlip's conclusions.
In addition to 99.999999% of experiments.

But you are not reading.

Oh I have read. At this time, I find a significant
FTL physical transmission effect to be theortically
and experimentally implausible, I'm NOT saying you
are wrong though. I'd be on your and TVF's ban-wagon
if I could see any "plausible" reason.

I did not said that GR is implausible. You *misread* me.

OK, good. then we're all in agreement. Regards

At least you read that part.

Juan, it's rather judgemental to decide what I've
read. I've been engaged in scientific study for
nearly 50 years now.

Nearly every day, I see a
new thing or a different way of seeing an old
thing.
Regards
Ken S. Tucker

[Mike]: There is nothing in Newton's law, F = dp/dt, that says forces
propagate at any speed.

[Mike]: You keep talking about "speed of gravity" but you never justified
why gravity must have a speed in the first place.

[Mike]: action_at_a_distance is sufficient for NM for all practical
purposes

[Mike]: In GR, there is only motion, induced by curvature of spacetime due
to the presence of mass-energy distribution, and vice versa. It is just a
clever model. No connection to reality necessarily.

[Mike]: We do not even know what gravity is.

[TomVF]: in LR, the transformations operate in only one direction, from
the local gravitational potential field to the moving frame. They do not
work in reverse.

[Wublee]: It is very clear from the following that LR manifests time
dilation. ** dt' = dt / sqrt(1 - v^2 / c^2) I don't know how you can
argue otherwise.

[Wublee]: In your LR equations, there is no mention of gravitational
potential. Thus, what you believe in does not really apply to the
equations of LR which you have published.

[Wublee]: Because of the twin's paradox, SR does not agree with anything.
It is utterly absurd of a conjecture.

[Wublee]: LR does not even degenerate to the Galilean transform at low
speeds.

[Wublee]: Yes, the Aether model of GR does seem to explain a great deal.
However, in this model, you will find the deflected angle of a photon
follows Snell's law. Thus, it is only the Newtonian result not what you
are expecting of GR result of twice the Newtonian.

[Wublee]: What you have described does not work for the curvature in
spacetime. This is why it was quickly abandoned by the founding fathers of
GR which does not include Einstein. Einstein was a nobody. He was a
nitwit, a plagiarist, and a liar.

[Carlip]: Let R contain a single mass M moving at a constant velocity. ...
Then both GR and Newtonian gravity agree that a test mass at p will
experience an acceleration toward the "instantaneous" position of M. In
particular, the direction of that acceleration will track the motion of M.

[Carlip]: Now, at time t=0, make the following change in R: stop the
motion of M. You apparently agree that this change will have no affect at
p until the time for a light signal to reach p from R.

If you really "agree completely with Low's mathematical reasoning," then
you accept this direct consequence of that reasoning.

[Carlip]: Write down the exact solution of the Einstein field equations
for a mass M that initially moves at a constant velocity and then abruptly
stops. ... Now just compute the acceleration at p.

[Carlip]: This is not a question of an "interpretation" -- it is a direct,
unambiguous mathematical prediction.

[TomVF]: The one and only mathematical question of importance here to the
speed of gravity issue is this: For a target body with a transverse
motion relative to the source mass, should we use the retarded gradient
or the instantaneous gradient to get the force?

[Carlip]: There is no such thing as a "retarded gradient." The gradient of
a function is the vector of its spatial derivatives. Time doesn't come
into it.

[Carlip]: It is also an elementary mathematical fact, of course, that if a
function at x at time t is determined by the behavior of some source at an
earlier time t', then the gradient of the function of x at time t is also
determined by the behavior of some source at time t'.

[TomVF]: 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).

[Carlip]: You can, in fact, do all of the calculations without ever using
a potential.

“Koobee Wublee" wrote:

[Wublee]: It is very clear from the following that LR manifests time
dilation. ** dt' = dt / sqrt(1 - v^2 / c^2) I don't know how you can
argue otherwise.

You have taken the meaning of "t" too literally. "t" is really "time"
itself in special relativity (SR) because it applies universally. But
because there is no reciprocity to the transformations in Lorentzian
relativity (LR), "t" in LR means only the reading on clocks in a single
frame. Those clocks are slowed by any motion that the frame might have
relative to the local gravitational potential field. And this clock-slowing
effect is just like the slowing a pendulum clock experiences when the
temperature increases: the clock slows, but nothing happens to real time as
used to measure change in the universe at large. So in LR, there is no time
dilation, only clock-slowing. The clocks in the local gravitational
potential field are "standards", and clocks with a relative motion run slow
relative to the standards.

For example, in the Global Positioning System (GPS), which uses LR clock
synchronization, all clocks in all orbits are rate-corrected once after
launch to agree with a ground master clock. Ever thereafter, all clocks on
the ground and in orbit run at the same average rate. GPS then continues to
operate without time dilation.

[Wublee]: In your LR equations, there is no mention of gravitational
potential. Thus, what you believe in does not really apply to the
equations of LR which you have published.

SR and LR are about the relativity of motion -- only. GR is about the
effect of gravitational potential on clocks. All my papers recognize this
difference, and most of them mention both effects on clock rates. The same
one-time corrections apply both to clock-slowing from motion and
clock-speed-up from orbiting in a weaker gravitational potential. See for
example Ref. [3].

[Wublee]: Because of the twin's paradox, SR does not agree with anything..
It is utterly absurd of a conjecture.

Then you are in the majority of people who have been taught SR but never
really understood it.

I agree SR is wrong, but only because it was recently
falsified by experiment.

I sharply disagree that it is absurd.

It is an
internally consistent model of nature that might have been right.

Read my
article in Ref. [4], which is designed specifically to explain SR to people
who do not understand how it can make sense. It uses a GPS-type
rate-corrected clock on board the spacecraft along with a "normal" clock so
the traveling twin always knows what time it is back on Earth "right now",
to help show how the twin's paradox plays out.

[Wublee]: LR does not even degenerate to the Galilean transform at low
speeds.

It doesn't need to. Think of LR as simply a way of describing what
happens to the rate of atomic clocks when immersed in a gravitational
potential field, or when moving through one. It doesn't have anything to say
about "time" per se.

[Wublee]: Yes, the Aether model of GR does seem to explain a great deal.
However, in this model, you will find the deflected angle of a photon
follows Snell's law. Thus, it is only the Newtonian result not what you
are expecting of GR result of twice the Newtonian.

Take a look at Eddington's derivation, Ref. [5]. The
refraction-in-an-optical-medium model gives double the Newtonian deflection,
just as observed.

[Wublee]: What you have described does not work for the curvature in
spacetime. This is why it was quickly abandoned by the founding fathers of
GR which does not include Einstein. Einstein was a nobody. He was a
nitwit, a plagiarist, and a liar.

Your hostility is misplaced.

Einstein eventually accepted aether,

accepted that it was represented by the gravitational potential field,

decried the geometric interpretation of GR, and wrote a paper showing why
"black holes" are impossible.

Most of the stuff you hate, attributed to
Einstein, is actually due to his followers, especially since 1970, who have
run amok with the theory but continue to get published and get funding by
claiming they are just testing and verifying "Einstein's theory".

The continual usage of "spacetime" with a double meaning, and switching
meanings as needed to settle any argument with students, is what you should
target. There is only one legitimate physical meaning of "spacetime" in GR,
and it has nothing to do with space. In brief, it means proper time
multiplied by c to express it in space-like units. See Ref. [6].

The math of GR works very nicely. The physical meaning of that math has
become so muddled by post-Einstein relativists that we'll have to bring
Einstein back from the dead to get it straightened out.

[This replies to Mike, Koobee Wublee, and Steve Carlip.]

"Mike" writes:
[Mike]: There is nothing in Newton's law, F = dp/dt, that says forces
propagate at any speed.

To truly understand physics, we must place its laws onto a foundation
based on logic. In the discipline known as "deep reality physics", there is
only one assumption: "no miracles allowed".

The premises that arise from logic alone rather than from experiments or
observations or philosophy or mathematics include these:

** Causality: Every effect has an antecedent, proximate cause.
** Creation: No creation ex nihilo; and no demise ad nihil

For the reasoning behind these and the other principles of physics, see
Ref. [1].

As this applies to your statement, when a force is applied to a target
body to change its momentum, that new momentum cannot arise from nothing
because that is creation ex nihilo. The momentum must be delivered by the
force. That means the force itself must have momentum (the product of mass
and velocity), which necessitates that the force propagates.

Students often object "What about the force of gravity holding a rock on
the ground?" (or some similar example). Even a rock is mostly empty space
and can be crushed into a much smaller volume. Gravity forces all its
free-to-move entities (such as atomic nuclei or vibrating molecules) to
fall. They do so until they collide with a neighbor entity, and they pass
along their momentum when they do so. That momentum continues to exist and
is passed from entity to entity until it reaches any point of rock-contact
with the ground. The ground is held in place by electrostatic forces and
sends the received momentum back into the rock, which pushes back on the
entities. As long as the force of gravity continues, this cycle of
exchanging momentum back and forth continues also, and is responsible for
the pressure the rock continually applies to the ground. If there were no
gravity to make rock constituents fall, the rock could apply no pressure to
another body. Even with gravity, if all rock constituents could be held
immobile (say, suspended from above by tiny "strings"), the rock could apply
no pressure. It is the (usually unobserved) motion of free rock constituents
within the rock that creates any pressure the rock applies and we measure as
"weight".

The downward pressure caused by gravity exists in every atom of the rock
on the ground, and it flattens or reshapes the rock to the extent that it
can. Only the back-force from the ground prevents the whole rock from moving
downward. So the net force on the rock and its net momentum are both zero.
But individual atoms or molecules are continually moving or vibrating to the
extent they can within the rock in response to these active forces and the
momentum they carry.

[Mike]: You keep talking about "speed of gravity" but you never justified
why gravity must have a speed in the first place.

Gravitation originates in a source mass and affects a target body at
some distance. Because action at a distance without intermediaries is a
logical impossibility, the force of gravity must propagate from the source
mass to the target body and transfer momentum to the latter by contact.

[Mike]: action_at_a_distance is sufficient for NM for all practical
purposes

Yes, but that is a form of miracle because it violates the "proximate"
part of the causality principle. As Newton himself said: "That one body may
act upon another at a distance through a vacuum, without the mediation of
anything else, by and through which their action and force may be conveyed
from one to the other, is to me so great an absurdity, that I believe no man
who has in philosophical matters a competent faculty of thinking, can ever
fall into it."

In other words, it requires a miracle. What is your justification for
allowing action at a distance as an explanation for any real, physical
process? Do you propose to allow miracles, or can you describe a way (that
no one else can) for one body to act on another without something passing
between them? Think about it.

"Mike" writes:
[Mike]: There is nothing in Newton's law, F = dp/dt, that says forces
propagate at any speed.

    To truly understand physics, we must place its laws onto a foundation
based on logic. In the discipline known as "deep reality physics", there is
only one assumption: "no miracles allowed".

    The premises that arise from logic alone rather than from experiments or
observations or philosophy or mathematics include these:
** Causality: Every effect has an antecedent, proximate cause.
** Creation: No creation ex nihilo; and no demise ad nihil

    For the reasoning behind these and the other principles of physics, see
Ref. [1].

    As this applies to your statement, when a force is applied to a target
body to change its momentum, that new momentum cannot arise from nothing
because that is creation ex nihilo. The momentum must be delivered by the
force. That means the force itself must have momentum (the product of mass
and velocity), which necessitates that the force propagates.

[Mike]: You keep talking about "speed of gravity" but you never justified
why gravity must have a speed in the first place.

    Gravitation originates in a source mass and affects a target body at
some distance. Because action at a distance without intermediaries is a
logical impossibility, the force of gravity must propagate from the source
mass to the target body and transfer momentum to the latter by contact.

[Mike]: action_at_a_distance is sufficient for NM for all practical
purposes

    Yes, but that is a form of miracle because it violates the "proximate"
part of the causality principle.

As Newton himself said: "That one body may
act upon another at a distance through a vacuum, without the mediation of
anything else, by and through which their action and force may be conveyed
from one to the other, is to me so great an absurdity, that I believe no man
who has in philosophical matters a competent faculty of thinking, can ever
fall into it."

    In other words, it requires a miracle. What is your justification for
allowing action at a distance as an explanation for any real, physical
process? Do you propose to allow miracles, or can you describe a way (that
no one else can) for one body to act on another without something passing
between them? Think about it.

[Mike]: In GR, there is only motion, induced by curvature of spacetime due
to the presence of mass-energy distribution, and vice versa. It is just a
clever model. No connection to reality necessarily.

    This mixes concepts badly. "Motion" in spacetime is nothing like motion
in 3-space. So you are using the terms "motion" and/or "spacetime" and or
"mass-energy" inappropriately. Indeed, no connection to reality is possible
without defining terms in a clear, unambiguous way. That is why I specify
"3-space" or "4-space" when I use such terms.

    One of the objections to the geometric interpretation of GR is that
spacetime curvature alone cannot initiate 3-space motion. Only a 3-space
force can do that.

[Mike]: We do not even know what gravity is.

    Many of us have had the pleasure of discovering what gravity is
physically during the past decade. See 20-author Ref. [2] for the latest
research results. In a nutshell, the apple falls from the tree because there
is a net graviton wind blowing down toward Earth because Earth blocks part
of the graviton wind coming up from below. The fact that this elegant,
intuitive picture also gives all the GR effects too is simply a delight.

    Perhaps you can express why this fundamental understanding of gravity
offends your sensibilities so much, especially now that all classical
objections have been answered in a satisfactory way.

and "Koobee Wublee" writes:
[TomVF]: in LR, the transformations operate in only one direction, from
the local gravitational potential field to the moving frame. They do not
work in reverse.
[Wublee]: It is very clear from the following that LR manifests time
dilation.  **  dt' = dt / sqrt(1 - v^2 / c^2)  I don't know how you can
argue otherwise.

    You have taken the meaning of "t" too literally. "t" is really "time"
itself in special relativity (SR) because it applies universally. But
because there is no reciprocity to the transformations in Lorentzian
relativity (LR), "t" in LR means only the reading on clocks in a single
frame. Those clocks are slowed by any motion that the frame might have
relative to the local gravitational potential field. And this clock-slowing
effect is just like the slowing a pendulum clock experiences when the
temperature increases: the clock slows, but nothing happens to real time as
used to measure change in the universe at large. So in LR, there is no time
dilation, only clock-slowing. The clocks in the local gravitational
potential field are "standards", and clocks with a relative motion run slow
relative to the standards.

    For example, in the Global Positioning System (GPS), which uses LR clock
synchronization, all clocks in all orbits are rate-corrected once after
launch to agree with a ground master clock. Ever thereafter, all clocks on
the ground and in orbit run at the same average rate. GPS then continues to
operate without time dilation.

[Wublee]: In your LR equations, there is no mention of gravitational
potential. Thus, what you believe in does not really apply to the
equations of LR which you have published.

    SR and LR are about the relativity of motion -- only. GR is about the
effect of gravitational potential on clocks. All my papers recognize this
difference, and most of them mention both effects on clock rates. The same
one-time corrections apply both to clock-slowing from motion and
clock-speed-up from orbiting in a weaker gravitational potential. See for
example Ref. [3].

[Wublee]: Because of the twin's paradox, SR does not agree with anything..
It is utterly absurd of a conjecture.

    Then you are in the majority of people who have been taught SR but never
really understood it. I agree SR is wrong, but only because it was recently
falsified by experiment. I sharply disagree that it is absurd. It is an
internally consistent model of nature that might have been right. Read my
article in Ref. [4], which is designed specifically to explain SR to people
who do not understand how it can make sense. It uses a GPS-type
rate-corrected clock on board the spacecraft along with a "normal" clock so
the traveling twin always knows what time it is back on Earth "right now",
to help show how the twin's paradox plays out.

[Wublee]: LR does not even degenerate to the Galilean transform at low
speeds.

    It doesn't need to. Think of LR as simply a way of describing what
happens to the rate of atomic clocks when immersed in a gravitational
potential field, or when moving through one. It doesn't have anything to say
about "time" per se.

[Wublee]: Yes, the Aether model of GR does seem to explain a great deal.
However, in this model, you will find the deflected angle of a photon
follows Snell's law. Thus, it is only the Newtonian result not what you
are expecting of GR result of twice the Newtonian.

    Take a look at Eddington's derivation, Ref. [5]. The
refraction-in-an-optical-medium model gives double the Newtonian deflection,
just as observed.

[Wublee]: What you have described does not work for the curvature in
spacetime. This is why it was quickly abandoned by the founding fathers of
GR which does not include Einstein. Einstein was a nobody.  He was a
nitwit, a plagiarist, and a liar.

    Your hostility is misplaced. Einstein eventually accepted aether,
accepted that it was represented by the gravitational potential field,
decried the geometric interpretation of GR, and wrote a paper showing why
"black holes" are impossible. Most of the stuff you hate, attributed to
Einstein, is actually due to his followers, especially since 1970, who have
run amok with the theory but continue to get published and get funding by
claiming they are just testing and verifying "Einstein's theory".

    The continual usage of "spacetime" with a double meaning, and switching
meanings as needed to settle any argument with students, is what you should
target. There is only one legitimate physical meaning of "spacetime" in GR,
and it has nothing to do with space. In brief, it means proper time
multiplied by c to express it in space-like units. See Ref. [6].

    The math of GR works very nicely. The physical meaning of that math has
become so muddled by post-Einstein relativists that we'll have to bring
Einstein back from the dead to get it straightened out.

and Steve Carlip writes:
[Carlip]: Let R contain a single mass M moving at a constant velocity. ....
Then both GR and Newtonian gravity agree that a test mass at p will
experience an acceleration toward the "instantaneous" position of M. In
particular, the direction of that acceleration will track the motion of M.

    Correct. The same would be true if M moved with arbitrary acceleration.
There was no need for the "constant velocity" assumption except to keep the
example simple. As for p, I'm assuming you mean it to be at rest in the
selected coordinate system, because moving with M would defeat the purpose
of the example.

[Carlip]: Now, at time t=0, make the following change in R: stop the
motion of M. You apparently agree that this change will have no affect at
p until the time for a light signal to reach p from R.

    Nonsense. What I agreed to was that the gravitational potential field at
p would not change until one light-time later than t = 0. However, it is
clear from logic, observation, and computer experiments that the force
operating at point p changes almost instantly, and any body at point p would
cease to accelerate toward mass M almost instantly. Your message fails
totally to recognize that field and force are independent physical concepts.
These two concepts have a mathematical connection, but one that is ambiguous
on the critical point of this discussion: instantaneous or retarded
gradient.

    A scenario very similar to yours and attempting to illustrate the same
points is illustrated in a caption and short animation at Ref. [7]. This
animation shows how force changes almost instantly, whereas field effects
such as light-bending experience light-speed propagation delay.

If you really "agree completely with Low's mathematical reasoning," then

you accept this direct consequence of that reasoning.

    No, Low made the same oversight you just did. Field and force are two
different things. One is retarded and the other is nearly instantaneous. But
the physics is very comfortable with that as long as force shapes field and
not vice versa.

[Carlip]: Write down the exact solution of the Einstein field equations
for a mass M that initially moves at a constant velocity and then abruptly
stops. ... Now just compute the acceleration at p.

    Same issue. More on this below.

[Carlip]: This is not a question of an "interpretation" -- it is a direct,
unambiguous mathematical prediction.

    You can only say that because you have apparently not understood the
real issue. (More below.)

[TomVF]: The one and only mathematical question of importance here to the
speed of gravity issue is this: For a target body with a transverse
motion relative to the source mass, should we use the retarded gradient
or the instantaneous gradient to get the force?
[Carlip]: There is no such thing as a "retarded gradient." The gradient of
a function is the vector of its spatial derivatives. Time doesn't come
into it.

    Here you make an elementary mistake. It takes two points (or one point
and a direction) to determine a vector. So there is most definitely a "time"
issue because there is no remote simultaneity in relativity. That means if
the two points are synchronized in M's frame, they are not synchronized in p's
frame; and vice versa. So the "gradient" cannot be the same for both frames
if they have a relative transverse motion.

    Please reflect on this point because it appears to be the key to
understanding why the speed of gravity issue cannot be reduced to semantics
or swept under the rug in the way that you suggest.

[Carlip]: It is also an elementary mathematical fact, of course, that if a
function at x at time t is determined by the behavior of some source at an
earlier time t', then the gradient of the function of x at time t is also
determined by the behavior of some source at time t'.

    In accord with the relativity principle, you are not entitled to adopt
the source mass frame as special and ignore the view from the target body
frame, or vice versa. Because of their relative transverse motion, each
frame gets a different direction for the gradient function.

[TomVF]: 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).
[Carlip]: You can, in fact, do all of the calculations without ever using

a potential.

    Of course. Potentials are simply a mathematical convenience. The core
point is that gravitational force shapes the gravitational potential field
(the subject of the field equations), and not vice versa. The latter has
light-speed propagation delay, the former does not.

    Once that distinction is made, the existing equations work. But if you
force a light-speed propagation delay onto the force, the equations go badly
wrong right away. (Orbits spiral.)

    However, I'm telling you little if anything you don't already know.. Why
the resistance to the obvious? Does tradition outweigh logic? -|Tom|-

REFERENCES:

[1] "Physics has its principles", in "Gravitation, Electromagnetism and
Cosmology", K. Rudnicki, ed., C. Roy Keys Inc., Montreal, 87-101 (2001);
also athttp://metaresearch.org/cosmology/PhysicsHasItsPrinciples.asp.

[2] "Pushing Gravity: New Perspectives on Le Sage's Theory of Gravitation",
M. Edwards, ed., Apeiron Press, Montreal (2002).

[3] "Gravitational force vs. gravitational potential",http://www.schriever..af.mil/GPS/PAWG/PAWG%201998/Papers/vanflandern.ppt.

[4] "What the GPS tells us about the twin's paradox", in "Einstein,
Relativity and Absolute Simultaneity" edited by W.L. Craig and Q. Smith,
Routledge, London & New York, pp. 212-228 (2008); also athttp://metaresearch.org/cosmology/gravity/gps-twins.asp.

[5] Sir Arthur Eddington, "Space, Time & Gravitation", Cambridge Univ.
Press, first published 1920, reprinted 1987, p. 109.

[6] "Does space curve?",http://metaresearch.org/cosmology/gravity/spacetime.asp.

[7] "What if the Sun suddenly disappeared?" Read animation #6 caption athttp://metaresearch.org/media%20and%20links/animations/animations.asp, then
view animation.

Tom Van Flandern - Sequim, WA - see our web site on frontier astronomy
research athttp://metaresearch.org