A theory of gravity based on special relativity

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Discussion Overview

The discussion revolves around a proposed theory of gravity based on special relativity, presented by Hai-Long Zhao. The theory aims to integrate the effects of time dilation and length contraction with the law of universal gravitation, leading to predictions that differ from general relativity, particularly in the context of the Gravity Probe B experiment. The conversation includes comparisons of predictions from Zhao's theory, general relativity, and Self Creation Cosmology regarding geodetic and frame-dragging effects.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Exploratory

Main Points Raised

  • Some participants note that Zhao's theory predicts a geodetic effect of zero and a frame-dragging effect that is only 1/4 of that predicted by general relativity.
  • Garth provides specific predictions for the Gravity Probe B experiment, comparing the expected results of general relativity, Self Creation Cosmology, and Zhao's theory.
  • Participants inquire about the expected error bars on the Gravity Probe B measurements, with Garth indicating that the expected accuracy is 0.01% for geodetic measurements and 1% for frame-dragging measurements.
  • Garth expresses a willingness to reconsider his theory if the results confirm general relativity, mentioning the Thomas precession and its implications for predictions.
  • RB seeks clarification on the distinctions between Zhao's theory and Self Creation Cosmology, questioning the interpretations of gravitational waves emitted by binary stars.
  • Garth asserts that both SCC and MVSR are expected to yield similar predictions regarding gravitational radiation as general relativity.

Areas of Agreement / Disagreement

Participants express differing views on the implications of the Gravity Probe B results for the competing theories. There is no consensus on whether the results would completely falsify any of the theories discussed, and multiple competing views remain regarding the interpretations of gravitational phenomena.

Contextual Notes

Participants note that the predictions of the theories may be falsified based on the outcomes of the Gravity Probe B experiment, which is still in the data analysis stage. The discussion highlights the complexity of the theories and the potential for differing interpretations of experimental results.

Who May Find This Useful

This discussion may be of interest to those studying gravitational theories, experimental physics related to gravity, and the implications of special relativity in gravitational contexts.

Garth
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A paper by Hai-Long Zhao A theory of gravity based on special relativity
We obtain the effects of time dilation and length contraction starting with the law of universal gravitation and based on the influence of gravitational field on the light. Covariant theory of gravity is obtained by combining law of universal gravitation with special relativity. We calculate the standard tests of general relativity, which basically agree with general relativity. However, our theory differs from general relativity in the predictions for GP-B test, with the geodetic effect is zero and frame-dragging effect only 1/4 of the result in general relativity. The anomalous precession of DI Herculis and origin of quasars are also explained in the paper.
This is an alternative gravitational theory that has incorporated the conservation of gravitational energy (Zhao's "mass variance") in SR, Self Creation Cosmology has done so in GR (see Resolving the Degeneracy: Experimental tests of the New Self Creation Cosmology and a heterodox prediction for Gravity Probe B).

Both theories may be falsified - along with GR - in the geodetic and frame-dragging measurements of the Gravity Probe B experiment, which at present is in the data analysis stage.

We wait and see!

Garth
 
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Just to make it absolutely clear when the GP-B results are published:
The predictions of three competing theories, General Relativity (GR), Self Creation Cosmology (SCC) and Zhao's 'Mass Variance SR theory (MVSR) now read:

1. GPB Geodetic precession
GR = 6.6144 arcsec/yr
SCC = 4.4096 arcsec/yr
MVSR = 0.0000 arcsec/yr


2. GPB gravitomagnetic frame dragging precession
GR = 0.0409 arcsec/yr
SCC = 0.0409 arcsec/yr
MVSR = 0.0102 arcsec/yr


So there does seem to have been a point in carrying out that experiment, all three theories may be falsified by the results.

We wait and see! :smile:

Garth
 
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Garth, do you know the expected error bars on these measurements?
 
SpaceTiger thank you for your question.

The error bars will be evaluated when the data is processed, the data is in a highly compact and concatenated form at present (see Bob Kahn's paper "Gravity Probe B mission ends" in Matters of Gravity (page 12)). They have carried out calibration trials of many kinds (see their website past highlights for details) in order to evaluate the errors.

They have published an expected accuracy of the geodetic measurement of 0.01% and the frame-dragging measurement of 1%. These two alternative theories above make gross deviations from the GR predictions and so the results should be clear to many many sigma!

Garth
 
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Garth said:
They have published an expected accuracy of the geodetic measurement of 0.01% and the frame-dragging measurement of 1%. These two alternative theories above make gross deviations from the GR predictions and so the results should be clear to many many sigma!

Ok, that's all I wanted to know. So...if the results confirm GR, will you consider your theory completely falsified?
 
SpaceTiger said:
Ok, that's all I wanted to know. So...if the results confirm GR, will you consider your theory completely falsified?
Basically yes, but first I would look into the Thomas precession again. If you have followed my meanderings on the Self Creation Cosmology thread you will have seen that whereas SCC predicts a geodetic precession of 5/6 that of GR, in SCC, but not GR, there is also a Thomas precession to allow for, which works out as 1/6 the GR geodetic precession. If you compare the literature (MTW page 1119 eq 40.34) and Will Covariant Calculation of General Relativistic Effects in an Orbiting Gyroscope Experiment eq 21 you will see the same expression for the geodetic precession but with a reversed sign convention. There are double negatives all over the place!

When I added the Thomas precession initially I used the wrong convention and added the two precessions making the SCC prediction equal to that of GR. I have since reworked the Thomas precession and am convinced that it should be subtracted, making the SCC prediction 2/3 that of GR.

If the experiment actually does turn up the 6.6 arcsec/yr value (as everybody expects) I shall look at that one more time before putting SCC to bed for good.

The definitive test is to see whether particles and photons fall at the same rate or not, SCC predicts photons should fall (accelerate) at a rate 3/2 that of particles. One consequence of this is the LIGO laser half-beams should be attracted towards the Sun daily by 10-12 metres, I have contacted Kip Thorne at LIGO about this and he replied "we do not have very good accuracy on transverse position of the LIGO beam; nowhere nearly good enough to test your predictions."

If someone did measure the transverse movement and prove that its upper limit is less than the SCC prediction at 3 sigma confidence then that would be an absolute falsification of the theory.

The really interesting question of course is: "If the results are 4.4"/yr or Zhao's 0"/yr would everybody else consider GR theory to be completely falsified - or would they simply add another epicycle?" :wink:

Garth
 
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Garth
Just to be clear it’s MVSR that is based on SR
SCC is based on GR with some modifications, right.

Is SCC primarily ‘yours’ or is this something several are looking/working at?

For both SCC and MVSR do you know if the theories have an opinion on the GR prediction of relativistic binary stars accelerating into smaller orbits emitting energy as Gravity Waves; and was ‘measured’ by http://nobelprize.org/physics/laureates/1993/index.html" (the accelerating part not the wave)?
Do they agree or have a different interpretation.

Myself I’m having trouble buying into any energy needing to leave the binary system at all, but we don’t need to deal with that here.
RB
 
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RandallB said:
Garth
Just to be clear it’s MVSR that is based on SR
SCC is based on GR with some modifications, right.
Is SCC primarily ‘yours’ or is this something several are looking/working at?
The theory is primarily 'mine' and the published papers are:-
On Two Self Creation Cosmologies
http://www.kluweronline.com/oasis.htm/5092775
and here:
http://novapublishers.com/catalog/product_info.php?products_id=1869
You may not be able to access these, however there is free access of the last two of these papers on the physics ArXiv and the published work can be recovered from there as follows:
1. gr-qc/0212111 ] The Principles of Self Creation Cosmology and its Comparison with General Relativity[/URL]
2. gr-qc/0302026 ]Resolving the Degeneracy: Experimental tests of the New Self Creation Cosmology and a heterodox prediction for Gravity Probe B[/URL]
3. gr-qc/0302088 ]The derivation of the coupling constant in the new Self Creation Cosmology[/URL]
4. astro-ph/0401136] The Self Creation challenge to the cosmological concordance model[/URL]
5. gr-qc/0405094] Self Creation Cosmology - An Alternative Gravitational Theory[/URL] however others have also worked on the theory since 1982, there have been to my knowledge 54 other author citations.
For both SCC and MVSR do you know if the theories have an opinion on the GR prediction of relativistic binary stars accelerating into smaller orbits emitting energy as Gravity Waves; and was ‘measured’ by http://nobelprize.org/physics/laureates/1993/index.html" (the accelerating part not the wave)?
Do they agree or have a different interpretation.
Myself I’m having trouble buying into any energy needing to leave the binary system at all, but we don’t need to deal with that here.
RB
SCC is conformally equivalent to canonical GR in vacuo so it is expected that the gravitational radiation from two point masses orbiting in vacuo would be the same as GR. MVSR also seems to predict the same gravitational radiation as GR.
Garth
 
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