Talk:Speed of gravity
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Speed of static gravity or gravity waves??
[edit]This is not an idle distinction. Gravitational waves move at the speed of light, but static gravitational effects "appear" to take instantaneous effect over infinite distance, at least for objects moving at constant transverse velocity. The same is true for electromagnetic waves vs. an electrostatic field.
It will help if people joining in who don't immediately agree with the above, will first read the following discussion and references to Feynman's texts and others, if they want to talk about the similar effects of electrostatics and gravitostatics: http://www.physicsforums.com/showthread.php?t=149794
Consider a distant "charge" or charged-object AT REST. Does it show "abberation" in its location (direction of its static field lines) to an observer in transverse motion, with respect to it? Answer: Clearly no, since the static field lines are already in place thoughout the universe, and the motion of the observer doesn't change their direction back to the source. They don't show any abberation to a moving observer, precisely BECAUSE they are static, and not "moving" radially outward, like a ray of light, from source to observer. They just "exist" everywhere, timelessly. Once one accepts this (no abberation for static fields), it's easy to turn the situation around with Lorentz invariance and say that the observation must be the same if the situation is the same, but we choose a frame in which the OBSERVER is at rest, but now the distant charged object is moving. It's the same physical situation but we've only changed frames. Doing this ALSO cannot change the direction from which the observer "feels" or detects the pull of the charge, so therefore a steadily-moving charge (no velocity changes) must appear to be, not where the charge WAS with a speed of light retardation-delay, but instead exactly where the charge is NOW (its "true position") with no correction for any "signal" delays! Thus, the electrostatic field of a steadily-moving charge points directly at it, no matter how far away from it you are, since the static field is "updated" (a retarded time extrapolation correction) at distances. The field "extrapolates" for constant velocity, and corrects the retardation effects for it. This all happens with no speed of light delay.
Now, none of this can be used to send signals faster than c, because the direction to a static source isn't a signal. The extrapolation term breaks down if the transverse velocity is NOT constant. To send a signal you need to make change in your source, and to do that, you need to accelerate a charge (or a mass) by wiggling it, and that acceleration is NOT updated instantly, at distance. Instead, it moves outward from the accelerated source with a speed-of-light retardation delay, exactly as we're used to, with light. The static field is updated instantaniously at distance, but a changing field (be it EM wave or gravity wave) is updated only at the speed of light. A moving observer DOES see abberation in any outwardly moving waves (EM or gravity), or signals, because they DO propagate from source to observer with a limited velocity of c. "Acceleration" for the source breaks the symmetry of the previous situation, and now we see intuitively why source-acceleration is necessary to generate EM or gravitational waves. Constant-velocity doesn't do it, because you can't tell who the velocity belongs to.
Thus, we see abberation in light from the Sun (its called "annual solar abberation"). It means the Sun appears optically 8.3 arcseconds "behind" (west, since the Sun moves west->east against the Zodiac) of its "true" position against the stars. However, the Sun's pull on the Earth (fortunately) points exactly to its true position, not its (false) optical position. If this didn't happen (as the article itself points out), there would be a retarding force on the Earth's orbit and it would spiral inward-- static effects help preserve conservation of momentum and angular momentum, even over long distances. If the Sun had a static electric charge, of course the pull from THAT would also point to its true position, not its mere optical position. But that doesn't mean static fields move faster than light. They don't "move" at all-- that's why they're called static fields.
So-- most of what's in this article about the speed of gravity, is nonsense. Static gravity is (in this sense) instantaneous. Gravity waves travel at c. The stuff about gravity waves above one Hz being nonexistant, and waves below 1 Hz traveling faster than light, is all nonsense (mainly due to Antichristos and a bunch of Tom Van Flandern followers) and should be reverted at once. I don't know how far you have to go back to get a "good" version of this article, but most of it needs to go. SBHarris 04:01, 27 January 2011 (UTC)
- Looks good, if you can reference it, feel free to add it to the article. PlantRunner (talk) 18:25, 28 February 2011 (UTC)
- I would support rewriting the article to remove the errors pointed out by Sbharris. Martin Hogbin (talk) 18:27, 6 January 2012 (UTC)
- Does the effect on space-time due to acceleration of mass in someway dwarf the other effect on space-time due to the position of the mass? If not, then I do not see how this could fail to result in allowing for super-luminal communication, provided that the tidal stresses are detectable by a reasonably sensitive strain gauge. I understand that without tidal forces, you could not in a sense detect how far away this mass could be, because the detector would be in freefall provided that no other mass exists.
- Even if acceleration of mass did have a larger effect on space-time, it appears that accelerations of mass, for the most part, are irrelevant for determining the space-time, as it is apparent that calculating orbits based on positions pretty much gives you the right answer.
- Of course, finding enough gravity that we can manipulate in order to do this test experimentally is out of the question (let alone allow for economical communication of information), but in principle, the same test for "tidal" forces (as it were) should work with electrostatic fields as well.siNkarma86—Expert Sectioneer of Wikipedia
86 = 19+9+14 + karma = 19+9+14 + talk 02:21, 21 November 2013 (UTC) - It also appears that "spooky action at a distance" has already long been shown to be possible in quantum physics theories. Sure, you cannot communicate two-way faster than the speed of light using only two entangled particles, but if you have two clusters of entangled particles that respond asynchronously, you should be able to preserve enough information to close the communication loop. If you are guessing that I just made that up, you would be correct, but to my surprise, I checked 1 minute ago on this information, and sure enough, someone else already thought of it:
https://en.wikipedia.org/w/index.php?title=Superluminal_communication&diff=576700390&oldid=575273736
Although such communication is prohibited in the thought experiment described above, some argue that superluminal communication could be achieved via quantum entanglement using other methods that don't rely on cloning a quantum system. One suggested method would use an ensemble of entangled particles to transmit information,[1] similar to a type of quantum eraser experiments.[2][3][4] As the quantum eraser experiments rely on a classical, subluminal channel for coincidence detection, it is unclear whether superluminal communication would be possible by this method. Physicist John G. Cramer at the University of Washington is attempting to replicate one of these experiments and demonstrate whether or not it can produce superluminal communication.[5][6]- Perhaps this was no accident. I did look at that page before today, though I currently don't know how long ago was that. I would have to check an old archive of my Firefox Browser History to see when I did that.siNkarma86—Expert Sectioneer of Wikipedia
86 = 19+9+14 + karma = 19+9+14 + talk 02:49, 21 November 2013 (UTC)
Speed gravity + Inflation of Space
[edit]There should be some easy way to estimate the speed of gravity knowing the rate of inflation of space and the dimension of a large galaxy. The gravity near the outer edge of a galaxy should appear to be much stronger in the direction of the center of the galaxy because the space was "smaller" between the edge and the center when the gravity from the center started toward the edge. So does Newton's inverse square law of gravitation need a rate of inflation term? Have any of these effects be calculated? Are they consistent with observations? Does anyone really know? Is it worth commenting in this article or at least cross referencing explanations in other pages? I am raising these questions because I am curious what the answers might be. —Preceding unsigned comment added by 97.65.82.66 (talk) 21:59, 14 March 2011 (UTC)
- What do you mean "when the gravity from the center started toward the edge?" Unless you're talking about a change in gravity (a change in quadrupole moment, as happens when stars rotate about each other, see Hulse-Taylor binary, ther is no "change in gravity" to move anywhere. Gravitationally, a system looks the same when when it merely contracts symmetrically, or expands. There's no "change" in the field to "travel." SBHarris 01:54, 15 March 2011 (UTC)
This article left me confused
[edit]If changes propagate at finite speeds but when it is static the information is instantaneous, wouldn't that make the gravity for an object that is suddenly stopped appear to come from two different points in space simultaneously? Why would gravity somtimes propagate instantaneously and somtimes propagate at speed of light? Doesn't make sense... --TiagoTiago (talk) 05:54, 31 October 2011 (UTC)
- "Suddenly stopping" is a change. If that happens, people far away do not see the stop (that inforamtion propagates at the speed of light). Instead the people far away, for the intervening time, see the object continue as though it hadn't stopped. They see it from one place, but now it's the wrong place. As soon as the change catches up to them, they see it at the correct place. That also applies to changing speeds. So long as it has moved at constant velocity since the change in speed, people at all distances see it at the true direction, AFTER the change gets to them, but see it at the wrong place before that. SBHarris 07:47, 31 October 2011 (UTC)
Lorentz covariant models
[edit]I added following statement in the section "Lorentz covariant models" (which was removed):
The Whitehead's theory of gravitation (1922) explains gravitational red shift, light bending, perihelion shift and Shapiro delay.[7]
- ^ Millis, M.G.; Davis, E.W., eds. (2009). Frontiers of Propulsion Science. Progress in astronautics and aeronautics. American Institute of Aeronautics and Astronautics. pp. 509–530.
- ^ Strekalov, D.; Sergienko, A.; Klyshko, D.; Shih, Y. (1 May 1995). "Observation of Two-Photon "Ghost" Interference and Diffraction" (PDF). Physical Review Letters. 74 (18): 3600–3603. Bibcode:1995PhRvL..74.3600S. doi:10.1103/PhysRevLett.74.3600. PMID 10058246.
- ^ Dopfer, Birgit (1998). PhD Thesis. Univ. Innsbruck.
- ^ Zeilinger, Anton (1999). "Experiment and the foundations of quantum physics" (PDF). Reviews of Modern Physics. 71 (2): 288–297. Bibcode:1999RvMPS..71..288Z. doi:10.1103/RevModPhys.71.S288.
- ^ Paulson, Tom (14 November 2006). "Going for a blast into the real past". Seattle Post-Intelligencer. Retrieved 11 July 2011.
- ^ Barry, Patrick (September 30, 2006). "What's done is done… or is it?". New Scientist. 191 (2571): 36–39. (subscription required)
- ^ Will, Clifford & Gibbons, Gary. "On the Multiple Deaths of Whitehead's Theory of Gravity", to be submitted to Studies In History And Philosophy Of Modern Physics (2006).
It is historically true, but DVdm and Neo. want to dicsuss it. The Whitehead's theory uses retardation (by the speed of gravity equal to the speed of light) and it can explain several effects like GTR. 195.113.87.138 (talk) 12:07, 31 May 2013 (UTC)
- Note - I don't really want to discuss this. I reverted two edits of yours that were not properly sourced ([1] and [2]). Then Neo suggested ([3]) that you bring another kind of edit (with a source this time) to this talk page for discussion. I don't know whether the source indeed backs the added content or whether the statement is worth adding to the article. Perhaps others? Cheers, 195. - DVdm (talk) 13:05, 31 May 2013 (UTC)
- In On the Multiple Deaths of Whitehead's Theory of Gravity is In 1922, the distinguished mathematician and philosopher Alfred North Whitehead (1861-1947) , then in his 60th year, published a relativistic theory of gravity with the property, which it shares with Einstein’s theory, of containing no arbitrary parameters. Furthermore, when suitably interpreted, it yields the same predictions as General Relativity (GR), not only for the three classic tests of light bending, gravitational redshift and the precession of the perihelion of Mercury, but also for the Shapiro time delay effect (Shapiro 1964), recently confirmed to one part in 105 (Bertotti et al. 2003). and the version proposed here is sufficient. I think. 195.113.87.138 (talk) 07:44, 3 June 2013 (UTC)
- Your own reference says it's been experimentally disproven. If it was never a mainstream theory and isn't currently accepted, does it really add anything to this particular article? Laura Scudder | talk 14:32, 11 June 2013 (UTC)
- This theory was not "disproven" until 70s (nevertheless in 70s somebody still prefer Whitehead: value of the gravitational constant is not a function of the prior geometry as Will and Ariel claim ... Since Whitehead’s formulae as they stand have not been disconfirmed ... Currently there is considerable interest in correlating relativity theory with quantum mechanics. The efforts made in this direction tend to support Whitehead rather than Einstein. [4]). It was a good educational example and shows, that the four main experiments (used for a confirmation of the general relativity) can be explained as retarded gravitation (with the speed of gravity exactly equal to the speed of light).195.113.87.138 (talk) 06:06, 12 June 2013 (UTC)
While I have not read the argumentation in this section in detail, I would simply observe that the statement "The Whitehead's theory of gravitation (1922) explains gravitational red shift, light bending, perihelion shift and Shapiro delay" is inappropriate unless some sort of connecting reasoning links this statement to the surrounding discussion. Was it considered valid once upon a time, but no longer is? If still not falsified, is it proposed to be equivalent to GR? If not, what distinguishes it? This is confusing; I wish it could be clarified, as it seems to be an significant and interesting historical side note, if nothing else. — Preceding unsigned comment added by 75.161.40.5 (talk) 04:37, 16 January 2014 (UTC)
Removed the statement about a research team in China
[edit]The result of a research team in China is faked and wrong
In Ref.[1], it is pointed out that Tang and coworkers’ result cannot be obtained from normal process and their result is faked.
In Ref.[2] it is concluded that their result seems to be drawn based on the misinterpreting of the known formula and the less careful data analysis.
Reference [1] Y. Zhu, Measurement of the speed of gravity, arXiv:1108.3761 [2] C. G. Huang, The observation of the Earth tide is irrelevant to the speed of gravity, Chin Sci Bull, 2013, 58: 3291–3294 — Preceding unsigned comment added by Zhuyin (talk • contribs) 06:41, 10 October 2013 (UTC)
Yan Zhou ?
[edit]Why is there a section on something from a Yan Zhou ? It seems he is from Agriculture Department of Hubei Province in China, not a physicist. I can't find anything else about him on google, nor his article on arXiv.org. And the pdf in the arXiv.org has a lot of references, but none that proves those variations on satellite orbits. — Preceding unsigned comment added by 77.119.131.141 (talk) 08:52, 4 July 2014 (UTC)
- Note: https://independent.academia.edu/YinZhu talk2siNkarma86—Expert Sectioneer of Wikipedia 15:05, 4 July 2014 (UTC)
The dear unsigned,
Please use your real name for your commenting.
I tried to link the arXiv:1108.3761v8 through the reference [28] here and I succeeded. Please try again if you failed to open this link before.
You are welcome to comment my article entitled “Measurement of the speed of gravity”, arXiv:1108.3761v8.
But, I don’t think it is a rational way to say that “none that proves those variations on satellite orbits” without a scientific comment on the article.
I addition, my name is Yin Zhu, not Yan Zhou. — Preceding unsigned comment added by Zhuyin (talk • contribs) 07:40, 14 July 2014 (UTC)
The dear unsigned, More than 8 weeks passed, have you had some of comments on my article entitled “Measurement of the speed of gravity”, arXiv:1108.3761v8. If you have, you are welcomed to show them. I hope you could show some of significant views about it.
If you could not have a scientific comment on it, I hope you should not have non- scientific comment on it. — Preceding unsigned comment added by Zhuyin (talk • contribs) 02:44, 9 September 2014 (UTC)
Chinese measurement
[edit]In the Gravitation article, a subsection entitled Speed of gravity has something to say about a 2012 Chinese measurement, whereas the main article here says nothing about it. Seems like Speed of gravity should say something about it, if it is reputable. Conversely, the Gravitation article seems to give the Chinese measurement a great deal of undue weight, given that it has nothing whatever to say about the topic except for the Chinese measurement. Could someone more familiar with this topic either take this on, or advise what ought to be done here (and there)?
In December 2012, a research team in China announced that it had produced measurements of the phase lag of Earth tides during full and new moons which seem to prove that the speed of gravity is equal to the speed of light.[1] The team's findings were released in the Chinese Science Bulletin in February 2013.[2]
Reflist for snippet above
[edit]- ^ Chinese scientists find evidence for speed of gravity, astrowatch.com, 12/28/12.
- ^ TANG, Ke Yun; HUA ChangCai; WEN Wu; CHI ShunLiang; YOU QingYu; YU Dan (February 2013). "Observational evidences for the speed of the gravity based on the Earth tide" (PDF). Chinese Science Bulletin. 58 (4–5): 474–477. doi:10.1007/s11434-012-5603-3. Retrieved 12 June 2013.
Mathglot (talk) 06:08, 24 July 2014 (UTC)
- I am not an expert on the subject but, as far as I can see, the above paper claims to show a phase shift (lag) between the action of the Moon's gravity on the Earth compared with that predicted by the Moon's position in space relative to the Earth. Although it might appear that this result confirms the generally accepted theory of gravitation (GR), quite the reverse is true as GR predicts no such phase shift and such a phase shift would make the Earth's orbit unstable. Martin Hogbin (talk) 08:58, 24 July 2014 (UTC)
Dear Sir Hogbin, If you should read “Measurement of the speed of gravity”, arXiv:1108.3761v8, you might get some of answers. — Preceding unsigned comment added by Zhuyin (talk • contribs) 02:50, 9 September 2014 (UTC)
How does one get the speed of gravity?
[edit]From Maxwell's Equations we can get the speed of electromagnetic radiation by multiplying μ0 with ε0, is there a way to get the speed of gravity from similar equations.
For example, replacing the differential form fo Newton's law with Gauss's law (the differential form of Coulomb's Law) — Preceding unsigned comment added by 195.194.89.201 (talk) 15:04, 8 September 2014 (UTC)
Possible observations
[edit]In November 2013, Y. Zhu announced that he observed the speed of gravitational force, calculating the variations of the orbit of the geosynchronous satellites perturbed by the Sun. It is shown that the gravitational force of the Sun acting on the satellite is from the present position of the Sun. It indicates that the speed of gravitational force is much larger than the speed of light in a vacuum. From this observation and the recent experiments, the structure of the fields of a moving source (a body or a charge) is studied. A method to measure the speed of gravitational force in laboratory and a line to indirectly test the wavelengths of gravitational waves are presented. [1]
- This looks like a rehash of an old argument. ArXiv is not a reliable source unless published elsewhere. Martin Hogbin (talk) 08:49, 25 September 2014 (UTC)
- To be fair this has been published elsewhere. (For future reference, the Arxiv abstract page will usually contain a link to the published version. Many journals require this as a condition for the worj being on ArXiv.) However, looking at the revision history of the arxiv entry it seems that this paper may have been rejected quite a few times before getting accepted somewhere. (Which usually happens eventually if you are persistent.)TR 10:55, 25 September 2014 (UTC)
- From what I can see, this looks like a rehash of the Laplace argument, discussed in the article. Martin Hogbin (talk) 11:55, 25 September 2014 (UTC)
- To be fair this has been published elsewhere. (For future reference, the Arxiv abstract page will usually contain a link to the published version. Many journals require this as a condition for the worj being on ArXiv.) However, looking at the revision history of the arxiv entry it seems that this paper may have been rejected quite a few times before getting accepted somewhere. (Which usually happens eventually if you are persistent.)TR 10:55, 25 September 2014 (UTC)
- This observation is based on the satellite motions. A detailed calculation is presented for the result. Did Laplace have some argument about the satellite motions?
Laplace presented some line for the speed of gravity. But, I proved that the gravitational force between two planets is certainly directed to the present positions of the two planets, not the retarded positions of them.
If you are able to understand how the orbit of a satellite is designed, you shall understand the result in my article.
- Your theory is therefore in accordance with the current generally accepted theory of gravitation, general relativity. Martin Hogbin (talk) 09:25, 26 September 2014 (UTC)
First, I think, the purpose of the wiki is for spreading information and knowledge quickly, not for stopping this spreading. It can solve some problem in the traditional way, such as monopolization and domination of message and knowledge. If it cannot be discussed or argued, science shall cannot be developed. In this sense, I do not think that it is in accordant with the purpose of the wiki to remove Tom van Flandern’s works from here.
Second, my result is an observation. The theory of gravity need be in accordant with an observation or experiment. If a theory is not accordant with the observation or experiment, it is invalid.
Third, if the result in my article is mistake, it is certain this mistake shall be pointed out by someone. Before no one is certain that the result in my article is mistake, it has to be regarded as valid.
- Your observations need to be published in a reliable source where they are actively peer reviewed. --NeilN talk to me 15:15, 3 December 2014 (UTC)
Some problems in the “Speed of Gravity”
[edit]1.The Static fields
It is clear and certain, both the electromagnetic and gravitational field can transfer energy. For example, for two interacting charges A and B, as soon as A is moved, the B is moved by the motion of A. And, it is well known, the gravitational field can cause the tides which is a very big energy.
Therefore, it is nonesense to state that a static field cannot transfer energy.
2.Steve Carlip’s "Aberration and the Speed of Gravity" may be wrong
In "Aberration and the Speed of Gravity", Carlip obtained the equation (2.4). But, now we know that equation (2.4) is a fundamental equation for both the electrodynamics and the general relativity. Please see: Jackson, J. D.(1998) Classic Electrodynamics, 3rdEd., chapter 14, John Wiley 7 Sons, Inc. & Ryder L. (2009) Introduction to General Relativity, Cambridge University Press, chapter 9. In Jackson’s “Classic Electrodynamics”, it is explained that the interactive term in the equation (2.4) is the same as a static field, the speed of it is infinite.
3.Thus, Flandern’s result in his paper “The speed of gravity: what the experiments say?” has not been negated by Steve Carlip. — Preceding unsigned comment added by Zhuyin (talk • contribs) 08:37, 3 December 2014 (UTC)
Orphaned references in Speed of gravity
[edit]I check pages listed in Category:Pages with incorrect ref formatting to try to fix reference errors. One of the things I do is look for content for orphaned references in wikilinked articles. I have found content for some of Speed of gravity's orphans, the problem is that I found more than one version. I can't determine which (if any) is correct for this article, so I am asking for a sentient editor to look it over and copy the correct ref content into this article.
Reference named "PRL-20160211":
- From First observation of gravitational waves: Abbott, Benjamin P.; et al. (LIGO Scientific Collaboration and Virgo Collaboration) (2016). "Observation of Gravitational Waves from a Binary Black Hole Merger". Phys. Rev. Lett. 116 (6): 061102. arXiv:1602.03837. doi:10.1103/PhysRevLett.116.061102.
{{cite journal}}
: Unknown parameter|lay-summary=
ignored (help) - From LIGO: Abbott, B.P.; et al. (2016). "Observation of Gravitational Waves from a Binary Black Hole Merger". Phys. Rev. Lett. 116: 061102. doi:10.1103/PhysRevLett.116.061102.
- From Binary pulsar: Abbott, Benjamin P.; et al. (LIGO Scientific Collaboration and Virgo Collaboration) (2016). "Observation of Gravitational Waves from a Binary Black Hole Merger". Phys. Rev. Lett. 116 (6): 061102. arXiv:1602.03837. doi:10.1103/PhysRevLett.116.061102.
Reference named "Nature_11Feb16":
- From First observation of gravitational waves: Castelvecchi, Davide; Witze, Alexandra (11 February 2016). "Einstein's gravitational waves found at last". Nature News. doi:10.1038/nature.2016.19361. Retrieved 11 February 2016.
- From LIGO: Castelvecchi, Davide; Witze, Witze (11 February 2016). "Einstein's gravitational waves found at last". Nature News. doi:10.1038/nature.2016.19361. Retrieved 11 February 2016.
I apologize if any of the above are effectively identical; I am just a simple computer program, so I can't determine whether minor differences are significant or not. AnomieBOT⚡ 07:30, 20 February 2016 (UTC)
Please change title
[edit]Create also a page titled: Speed of quantum information.
Then merge the pages:
- Speed of quantum information (or quantum transmission)
- Speed of light in the classical void
- Speed of gravity
under the general name: Speed of color (the chromodynamic chroma) and maintain the subarticles as parts of that new page. — Preceding unsigned comment added by talk) 18:22, 26 April 2016 (UTC)
- The title of the article is wrong! It should be "The Speed of Gravitational Waves" or "The Speed of Gravitational Radiation". The current title is like saying "The Speed of Electromagnetism". Betaneptune (talk) 20:05, 7 July 2020 (UTC)
- Speed of electromagentism would be fine, in my opinion. Eveery effect of electromagnetism is mediated by light. I think Speed of gravity is the least confusing. --MGChecker (talk) 21:04, 7 July 2020 (UTC)
Assessment comment
[edit]The comment(s) below were originally left at Talk:Speed of gravity/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.
This article is currently a hodge-podge of views on the issue, all covered breifly. The lead is pathetic, and Van Flandern's views take up too much of the article (although this is because the rest of the article needs expanding). --EMS | Talk 05:41, 29 November 2006 (UTC) |
Last edited at 05:41, 29 November 2006 (UTC). Substituted at 06:40, 30 April 2016 (UTC)
'Static Fields' section without any reference
[edit]79.74.13.236 (talk) 14:33, 12 September 2020 (UTC)The 'Static Fields' section ( https://en.wikipedia.org/wiki/Speed_of_gravity#Static_fields ) lacks any reference. It effectively claims that the potential/field seen at a certain instantaneous distance d from the field-producing object is independent of the velocity of the observer if this velocity is constant. This flatly contradicts well known features of electrodynamics like the Liénard–Wiechert potential (https://en.wikipedia.org/wiki/Li%C3%A9nard%E2%80%93Wiechert_potential ) and also Special Relativity ( https://www.feynmanlectures.caltech.edu/II_26.html , Fig. 26-4) which show that the static fields are velocity dependent as well.
- Agreed. "These changes in direction of a static field are, because of relativistic considerations, the same for an observer when a distant charge is moving, as when an observer (instead) decides to move with respect to a distant charge. Thus, constant motion of an observer with regard to a static charge and its extended static field (either a gravitational or electric field) does not change the field." We should be able to calculate the fields in any inertial frame without reference to any other. The article seems to imply that the field in the moving frame should just be copied from that in the frame in which the field is static. That stands relativity on its head. NB: I am not a physicist. Unhandyandy (talk) 02:20, 26 June 2023 (UTC)
Date of Laplace's theory - two years mentioned
[edit]Under "Laplace":
The first attempt to combine a finite gravitational speed with Newton's theory was made by Laplace in 1805.
Ender the animated GIF in that section:
In 1776, Laplace considered a different mechanism ...
Which year was it? Mazz0 (talk) 10:28, 13 May 2022 (UTC)
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