Gravity speed vs light speed experiment

In summary, if the steady state pull peak is determined, it can be used to measure the speed of gravity. However, if the peaks are not coincidental, then there may be something wrong with general relativity.

Is this a valid experiment for testing gravity speed.

  • Are gravimeters sensitive enough?

    Votes: 1 100.0%
  • Can a gravity peak be determined?

    Votes: 0 0.0%
  • Can extrapolation methods be accurate?

    Votes: 0 0.0%
  • Has this experiment been done before?

    Votes: 0 0.0%

  • Total voters
    1
  • #36
1bobwhite said:
Nearly all of the responses to this experiment have apparently been made from theory only, and with an irritation that an attempt is being made at possibly showing that the GR theory may be in need of reconsideration.

That doesn't describe any of the response that I've seen. I think you've mis-read and/or mis-interpreted the responses.

1bobwhite said:
Well my "agenda" is to try to establish a repeatable demonstration of the real world forces that can be compared to the theoretical assertions.

You've missed the points that have been made. First, the thing you say you are trying to demonstrate was already demonstrated over 200 years ago by Laplace, when he showed that the stability of the planetary orbits imply virtually no aberration in the force of gravity. This is a well-known fact. Second, the results of this demonstration have already been "compared to the theoretical assertions". In particular, the absence of discernable aberration is consistent with the only empirically viable theories of gravity that we possess, in which the propagation speed if c. There is no known empirically viable theory of gravity in which the propagation speed differs from c, which is one of the things that makes it so difficult and contentious when trying to design experiments to test for the speed being different from c. But for the purposes of this thread, all of that is irrelevant, because the one thing we know for sure is that the proposal you are discussing, to infer the speed of propagation from simple force aberration, is untenable.

1bobwhite said:
Whether the results confirm or refute the supposed facts of these theories will have to be determined after the data is in.

Again, you've missed the point. The data you're discussing is already "in". It's been "in" for over 200 years. And the theoretical implications of this particular bit of data are well understood (by physicists).

1bobwhite said:
Many of my references and reasons for making the attempt at the experiment are contained in the following article: http://iopscience.iop.org/0004-637X/590/2/683/fulltext

All the excerpts you quoted from that reference simply confirm what people here have been telling you. None of those proposed observations are of the kind that you are discussing. You are talking about measuring the direction of the force, i.e., simple force aberration, which is already well known. There is no appreciable aberration in any relativistic force, and this applies to electromagnetism as well as gravity and the strong and weak nuclear forces.


1bobwhite said:
Excerpt: 1 A similar conclusion was reached by Carlip (2000) in the context of binary motion, in esponse to a proposed bound on the speed of gravity by Van Flandern (1998).

A foot note to show that Van Flandern's proposal was being considered with recognition for his work, that has been referred to here as "crackpot".

Again, the excerpt you quoted simply confirms what people have been telling you. Van Flandern was indeed a crackpot, as can be inferred from the excerpt that you quoted. He made the same elementary mistake that you are making, i.e., he supposed that the absence of aberration in the force implies a Laplacian lower bound on the propagation speed. The is a well known fallacy for over a century, and was even described as a fallacy in the paper that Van Flandern cited as his source.


1bobwhite said:
All I have heard on this forum so far is the negatives of how wrong I am in my thinking and how impossible and worthless the experiment is.

Your thinking IS wrong. As to the experiment, it isn't so much that it's worthless or impossible, it's just redundant. The absence of gravitational aberration has been a well established empirical fact for centuries.

1bobwhite said:
Not one single post has been made for how to design a workable experiment or how to improve a procedure to make extremely sensitive measurements.

That's simply not true. Many people have pointed out the most sensitive way of determining the aberration of the gravitational force, namely, by observing the orbital stability of the planets, from which we can say that there is no discernable (first order) aberration in the force of gravity. And of course this is entirely consistent with general relativity and with a propagation speed of c.

1bobwhite said:
Why are there so few amateurs taking up this challenge?

I think you underestimate the intelligence of most amateurs, who are fully capable of grasping that the absence of aberration in the force of gravity is (1) perfectly well established by observation, and (2) perfectly consistent with general relativity and a propagation speed of c.
 
Physics news on Phys.org
  • #37
Russell E,

Thank you for your point by point explanation. But just a few more questions though.

Does the article : http://iopscience.iop.org/0004-637X/590/2/683/fulltext agree with or disagree with the Fomalont and Kopeikin experiment?

If there in no apparent aberration in the gravity force in the solar system even at the extreme distances of Uranus and Neptune, how is that consistent with the speed of light that has such a time delay at those distances?

If there is a propagation speed of gravity, what is it?

Finally, I have full faith in the efforts of our amateur community, and in no way am I underestimating their intelligence.

Thank you DaleSpam, for your answer.

Bob.
 
Last edited:
  • #38
1bobwhite said:
If there in no apparent aberration in the gravity force in the solar system even at the extreme distances of Uranus and Neptune, how is that consistent with the speed of light that has such a time delay at those distances?
The time delay to Neptune is nothing compared to the age of the sun.

Maybe this analogy will help. Let's say that you have a metal plate that you can push down on. If you push on it briefly you will get a ripple which goes outward at the speed of sound in the plate. However, if you push and hold it you will get a momentary ripple followed by a static deformation. Measurements of the static deformation, such as the direction of the path of steepest descent, will tell you nothing about the speed of sound in the metal.

Similarly, suppose that you were to charge up a sphere with an electrostatic charge. Measurements of the static e-field cannot give you any information about the speed of light.

In this case, the gravitational field of the sun has been essentially static for eons. Measurements of it will not give you information about the speed of gravity.

Do you see the similarity in these situations and understand why none of them provide any information about the characteristic wave speed?
 
Last edited:
  • #39
DaleSpam,
Your analogies are good, but they also show the possibilities for further experimentation.
For instance, let's say gravity between the sun and the Earth is static as you say and under tension and distorted, it is nevertheless still a continuous connection between the two bodies. As with the steel plate or a drum head that is under stress distortion, any further momentary distortion or "ripple" will proceed from the source and radiate through the material at the speed of that materials propagation rate.

The search for gravity waves is a search for these ripples. And although the proposed experiment misses the point as you have said, the search for the ripples may also be directed to the noise and unexplained gravity signals of the sensitive gravimeters that will be used in the experiment.
The next logical step would be to learn how to induce the ripples so that the experiments already in place could detect them. But that is for another forum.
 
  • #40
1bobwhite said:
any further momentary distortion or "ripple" will proceed from the source and radiate through the material at the speed of that materials propagation rate.

The search for gravity waves is a search for these ripples.
Exactly, yes.
 

Similar threads

Replies
8
Views
2K
Replies
22
Views
3K
Replies
66
Views
12K
Replies
18
Views
4K
Replies
10
Views
3K
Replies
29
Views
4K
Back
Top