Kopeikin and "the speed of gravity"

Tom Van Flandern,

You say gravitational potential travels at c but gravity forces travel at billion times c. Then, if you got a disturbance in the potential then a disturbance in gravity which is manifested by a resulting gravity forces can only travel at the speed limit of what is causing it, because should it go faster, causality will be violated.

Then the fact is...

who cares of "morbid" potentials. all we care about is disturbances. gravity is a disturbance of the "morbid" cosmological gravity field.

and the question is:

I've been reading your answers to Jim's questions about gravity. Why are you saying to him to think at gravity as an acceleration while you're talking about the "speed of gravity" forces? If gravity is like in GR, all we care is potential disturbances. There is simply no force (period) and the issue of "speed of gravity" is meaningless.

Some people want their cake and eat it too....

Your trully

Mark

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">You say gravitational potential travels at c but gravity forces travel at billion times c. Then, if you got a disturbance in the potential then a disturbance in gravity which is manifested by a resulting gravity forces can only travel at the speed limit of what is causing it, because should it go faster, causality will be violated.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

It is almost never true in physics (as opposed to mathematics) that a function and its derivative have the same properties. For example, in SR, there are clear limits on speed (&lt;= c), but none on acceleration.

More to the point, in physical models of gravitation (unlike mathematical models), the gravitational potential field is equated with the "light-carrying medium" or the "space-time medium". Gravitational force, by contrast, is associated with high-speed momentum carriers called "gravitons" that shape the potential field, but obviously cannot <i>ne</i> the potential field.

Note also that the relation "force is the gradient of potential" has never been expected to hold in detail for gravitational waves, for example. If it did, a gravitational force would accompany every gravitational wave, and detection would be easy.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">who cares of "morbid" potentials. all we care about is disturbances. gravity is a disturbance of the "morbid" cosmological gravity field.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

?? Whatever that means, I'd like to see you try to make a physical model of gravitation out of it. See <i>Pushing Gravity</i> for a complete physical model of gravitation, including quantum gravity, that meets all experimental constraints and makes physical sense.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">I've been reading your answers to Jim's questions about gravity. Why are you saying to him to think at gravity as an acceleration while you're talking about the "speed of gravity" forces? If gravity is like in GR, all we care is potential disturbances. There is simply no force (period) and the issue of "speed of gravity" is meaningless.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

I find it strange that so many relativists don't realize that GR could never be compared to observations if you didn't take the gradient and derive equations of motion. But some of them like to confine their interests to their comfortable mathematical shell and ignore messy reality.

In our latest paper, “Experimental Repeal of the Speed Limit for Gravitational, Electrodynamic, and Quantum Field Interactions”, T. Van Flandern and J.P. Vigier, Found.Phys. 32(#7), 1031-1068 (2002), we show that the geometric interpretation of GR violates the causality principle and the "no creation ex nihilo" principle, and is therefore not physically viable. That leaves only the force interpretation of GR, the one favored by Einstein, Dirac, Feynman and others.

"Force" here is used in the broad and familiar sense. Strictly speaking, we are talking about acceleration, not force, at the macroscopic level. Only in the microscopic details can we see something with the nature of force acting. Even then, it can be regarded as a series of momentum impulses.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Some people want their cake and eat it too....<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

Delicious! -|Tom|-

It would seems that the 'claims' by Kopeikin were taken up by space.com as well. They have an article about it claiming it to be the first 'true' measurement of the speed of gravity. The link is [url] www.space.com/scienceastronomy/gravity_speed_030107.html [/url].
Perhaps Meta Research can get them to post the response article on their site as well.

Rudolf

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">[mark]There is simply no force (period) and the issue of "speed of gravity" is meaningless. <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">Quite the opposite - there are no potentials, they are no more than energy-related mathematical abstractions, forces/accelerations are the true observables.
Gravity can be easily modelled as instantaneous momentum exchange with subsequent energy redistribution through a slow inertial medium (aether/spacetime/vacuum). GR deals only with the energy-related facet of gravity, it's a purely phenomenological theory that purposefully doesn't deal with the true hidden cause of gravity.

First off I’m an idiot. I’m just a dumb mechanical engineer with no formal education in physic, science, etc, etc. I’m just an ol’Georgia boy living in Kansas.

CNN.com just issued the Kopeikin article on their website. My first impression of the Kopeikin article was that it was wrong and there was no way the “Speed of Gravity” was the same as the “Speed of Light”. I did a quick search on the Internet and came across Tom Van Flandern’s dissertation on the speed of gravity and by way of that to this board.

Anyway, I’m still digesting both the kopeikin info and Tom Van Flandern’s “The Speed of Gravity, but I tend to see Toms reasoning if for no other reason then that it follows closer to my sometimes faulty world view. I think black holes would have a problem with gravitational attraction external of the event horizon, if the gravity acceleration were not quite a bit higher then the speed of light. Actually I’m still not sure what exactly gravity it. But like I said I’m in idiot.

Thanks for making me think. I’ll go back and lurk in the background.



Ben

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">First off I’m an idiot. I’m just a dumb mechanical engineer with no formal education in physic, science, etc, etc. I’m just an ol’Georgia boy living in Kansas.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

And Einstein was once just a lowly clerk in the Patent Office.

<blockquote id="quote"><font size="2" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote">Actually I’m still not sure what exactly gravity it.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">

You might really enjoy the new book <i>Pushing Gravity</i>, which has a complete model of exactly what gravity probably is. It's available at the Meta Research store (as one of only three books we recommend to our members), as well as at Amazon and lots of other places. -|Tom|-