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7th May 2014, 08:02 AM | #2521 |
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30th July 2014, 01:05 PM | #2522 |
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I'm not certain that this has been mentioned before.
A hallmark characteristic of crackpots seems to be their total unwillingness or incapability to recognize and understand even the the most simple and stark demonstration that any facet of their dogma is false. This inability to yield on even the most trivial detail regarding their fantasies is quite remarkable. |
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30th July 2014, 01:32 PM | #2523 |
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It's true. The problem is that they will not accept that their fantasies are just that. If somebody shows them Einstein saying space is inhomogeneous or the speed of light varies with position, the crackpot will utterly reject it, and comfort themselves by calling the other guy a crackpot. Even though what Einstein said is there in black and white and a matter of public record, with professional endorsement. It is truly bizarre.
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30th July 2014, 02:58 PM | #2524 |
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The funny thing is, I don't believe in GR just because Einstein said it. I believe in GR because it's been carefully tested, by people (a) checking its equations for internal consistency and (b) devising experimental measurements and comparing them to GR calculations.
The thing I strongly believe to be true is that actual GR calculations, using Einstein's GR equations, are internally consistent and have passed extraordinarily-stringent experimental tests. The equations, in the form used to make the predictions, are widely taught, researched, explained in standard textbooks, and the meaning thus conveyed is uncontroversial. This is what I mean when I say "I believe GR is true" or "I know/understand GR". I know the same version everyone else knows, the version that's passed experimental tests. I furthermore believe that Einstein was talking about the same GR that I believe in, and that his words have a reasonably clear meaning to people other than yourself, you being a hostile witness who's actively mining for things to misunderstanding. However, my belief in the latter is much weaker than my belief in the former. The standard version of GR, the equationy version, the Misner Thorne and Wheeler version, has been tested, and I'm happy to have learned it and to understand it well and to be confident in its reliability (within the domains in which such confidence is warranted), and everyone who claims to know GR will say the same thing. If it were true that Einstein's popular writings describe something else---some equationless theory that's not the one MTW picked up on---well, this "something else" theory would be untested, undeveloped, cannot be called "General Relativity", and would not inherit the intellectual heritage of the known/tested/taught version of GR. (I reiterate that you have not identified a "something else" in Einstein's writings, only familiar things that you personally misunderstood.) Can you take your interpretation of Einstein's words and make your prediction for, say, the inspiral of the Hulse-Taylor binary pulsar? Go ahead. |
30th July 2014, 03:58 PM | #2525 |
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Me too. I've said repeatedly that GR is one of the best-tested theories we've got, and that the evidence is actually more important than what Einstein said.
Me too. I've referred to Clifford Will's Confrontation between General Relativity and Experiment on many occasions. That isn't true. The meaning is controversial. And one thing at the heart of that controversy is the speed of light. Only I'm not the hostile witness, and I don't misunderstand. I point to what Einstein actually said about the speed of light varying with position, and I point to Magueijo and Moffat and Ned Wright and the Baez website and the NIST optical clocks and more to back up what I'm saying. You know, this kind of thing: "Einstein talked about the speed of light changing in his new theory. In his 1920 book "Relativity: the special and general theory" he wrote: "... according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity [...] cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity [Einstein means speed here] of propagation of light varies with position." This difference in speeds is precisely that referred to above by ceiling and floor observers."
Originally Posted by ben m
Originally Posted by ben m
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30th July 2014, 04:31 PM | #2526 |
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This is clearly the opposite of what you have repeatedly said. You routinely repudiate contemporary physics, indeed any physics since 1920, and any use of GR out of the hands of Einstein. This means that you reject the theory as it is tested.
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I think that it might be nice to adopt a slogan from another realm: Cranks believe their theory works because it seems right, scientists believe their theory is right because it seems to work. |
30th July 2014, 06:46 PM | #2527 |
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I have spent a good deal of my time over the last three years studying physics (call it a hobby). The dozens of lectures, texts and papers I have studied from around the world include physics concepts and principles defined by mathematical equations and mathematical descriptions of physical phenomena. Never do the authors and professors say, "Newton wrote this," "Einstein said this" or "Maxwell believed that."
The physical systems are described and analyzed mathematically. It does not matter if the subject is statistical mechanics, relativity, quantum field theory, etc.; it's the mathematics that defines and describes the physical systems. It seems that using and depending on the words of the "masters" is exclusively a crackpot indulgence. |
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30th July 2014, 07:00 PM | #2528 |
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I have sat in on many academic lectures and seminars where people did discuss what Newton believed and what Maxwell believed. The evidence for the discussion was, for the majority of claims, a rigourous analysis of the mathematics presented in their works.
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30th July 2014, 07:01 PM | #2529 |
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An important part of Farsight's method is what may be called scriptural exegesis, sacred-book interpretation, or in more blunt terms, book-thumping. Complete with saying how wrong it is to deny the authors of the thumped books. If my experience is any guide, it is *very* rare in physics crackpottery, and indeed most forms of crackpottery, though it is common in creationism.
Physics crackpots usually argue more like their mainstream counterparts, addressing theories without considering their favorite theorists to be inspired prophets of revealed truth whom it would be wrong to question. However, they may also make lots of ad hominem arguments, like what orthodox oxen mainstream physicists are. |
30th July 2014, 07:43 PM | #2530 |
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Funny that you fail to quote the following paragraph (by bold)
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30th July 2014, 09:36 PM | #2531 |
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31st July 2014, 12:52 AM | #2532 |
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Yes. The Baez website has been referred to here because it includes a crackpot index. Only when it comes to what Einstein said and the speed of light varying in the room you're in, the Baez website agrees with me. The irony is delicious. It means I'm not the crackpot. So if I'm not the crackpot, who is?
Originally Posted by Perpetual Student
Originally Posted by Kwalish Kid
Originally Posted by Kwalish Kid
Originally Posted by lpetrich
Originally Posted by Russ Dill
"From quantum electrodynamics it can be found that photons cannot couple directly to each other, since they carry no charge, but half wavelength is a positive charge and the next half wavelength is a negative charge". The issue we were discussing was that the QED given explanation says pair production occurs because pair production occurs, spontaneously like worms from mud. There's an obviously tautology with that. It's crackpot, it's cargo-cult science. What actually happens is that one photon interacts with the other. PS: this forum is very slow. |
31st July 2014, 02:06 AM | #2533 |
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Is The Speed of Light Everywhere the Same? stated "Given this situation, in the presence of more complicated frames and/or gravity, relativity generally relinquishes the whole concept of a distant object having a well-defined speed." Farsight, however, seems to think that the variation of the speed of light in general relativity is well-defined. He ought to stop thumping his heroes' writings and work out how to calculate this variation. He won't get taken seriously by anyone working on general relativity unless he does so.
Disdain for math again. If math is an important part of a theory, then a rigorous analysis of it is a Good Thing.
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31st July 2014, 05:30 AM | #2534 |
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Farsight has expressed a curious set of opinions on what constitutes physics crackpottery. He has described supersymmetry, magnetic monopoles, string theory, multiverses, etc. as crackpottery, because there is no evidence for them, or at least so he claims.
That is strange, because that would consign *any* untested prediction of a theory to crackpottery status, and because that would imply that theorizing is not allowed to get ahead of observation and experiment. I've seen some criticisms of string theory that it's too far ahead of observation and experiment, but what Farsight seems to propose goes too far in the opposite direction. So would these hypotheses be crackpottery?
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31st July 2014, 05:41 AM | #2535 |
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The point is that Einstein "talked about the speed of light changing". And that this doesn't just apply to distant objects, it applies to the room you're in. Hence "this difference in speeds is precisely that referred to above by ceiling and floor observers". The Baez article backs me up. Not Perpetual Student.
I wouldn't consign *any* untested prediction of a theory to crackpottery status. |
31st July 2014, 07:05 AM | #2536 |
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31st July 2014, 07:28 AM | #2537 |
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Excuse me! I have never rendered any opinion on the speed of light in GR, simply because it is not a question I have studied. However, I do see that the authors of the article you linked do say this:
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31st July 2014, 08:28 AM | #2538 |
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I'm not at all confused, and I reiterate this: yes, "relativity generally relinquishes the whole concept of a distant object having a well-defined speed". But we aren't talking about distant objects. We're talking about light in the room you're in. The light at the ceiling goes faster than the light at the floor. If it didn't light wouldn't curve, your pencil wouldn't fall down, and the NIST optical clocks would stay synchronised. Remember you said "A hallmark characteristic of crackpots seems to be their total unwillingness or incapability to recognize and understand even the most simple and stark demonstration"? The parallel-mirror gif is the simple stark demonstration.
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31st July 2014, 08:40 AM | #2539 |
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That passage is a canonical example of Farsight confusion: you are talking about distances, yet you claim that you are not talking about distances.
In order to study physics, one has to study how physics problems are presented and solved and how physics applications are considered and implemented. If one has never done this, as Farsight seems not to have done, then one misses the very basic elements of physics. Of course, many physicists also miss the fundamental operations of their own discipline when asked to consciously consider it, but they at least have the opportunity and the basic knowledge to be lead to a proper consideration.
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31st July 2014, 08:51 AM | #2540 |
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Since I'm only an amateur studying textbooks, lectures and papers that I can find online, my experience is limited. It's true that Newton, Einstein, Maxwell, Heisenberg, etc. may be discussed in passing when the equations describing the physics are developed and discussed, but the real physics is based on the equations and experiments, not the words of the "Masters."
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31st July 2014, 09:11 AM | #2541 |
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I thought what you wrote was clear and insightful: if one is studying physics, then you study the theory and its relationship to observations. Who came up with the theory is interesting, but not necessary for comprehension and use. It is not merely in amateur study of physics that one experiences things as you described.
As the philosophers say, you are describing the study of physics qua physics (i.e., physics as itself), where as I was trying to add to the discussion by describing the study of physics as a conceptual, rhetorical, historical or sociological subject or a study of physicists themselves. I am perhaps biased to a certain type of study that takes physics seriously as a means of generating reliable knowledge rather than a study of it as a means of producing text, but given what I have seen the majority of scholars studying physics in these secondary manners share my bias. What I sought to point out was that when one is studying physicists, then one studies their statements and their statements as expressed in the structure of their theories. Sometimes there are aspects to the structure of their theories that they miss, but the "masters" were pretty good about understanding the structures of their theories. I can't remember the reference, but Einstein noted a debt to Maxwell in pointing out where relativity theory made its conceptual advances and one can indeed find places in Maxwell (early in Matter and Motion, for example) where he points out necessary assumptions in the structure of classical physics, assumptions that were later replaced by Einstein. If we are interested in studying Einstein, then we should look carefully at what he had to say and how he commented on and personally used relativity theory. If we want to study relativity theory, we should look carefully at an accepted presentation of the theory (one isomorphic to, or that otherwise preserves the content of, other presentations) and its relationship to observations, regardless of whether or not it matches Einstein's peculiar commentary. Einstein's comments might produce an effective teaching tool (though the more I read, the less I find Einstein's conceptual choices helpful), but they can at best be an aid to understanding the structure and the empirical evidence. |
31st July 2014, 10:00 AM | #2542 |
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The question seems to come down to this:
In my own frame of reference, whether in an inertial frame, accelerating, rotating or in a gravitational field, will I measure any source of light from any direction traveling by me at anything other than c? I admit that I have not really studied this question, however I believe, based on what I've read, that no source of light from any direction would be measured at anything other then c. Is that not correct? |
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31st July 2014, 12:18 PM | #2543 |
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Please explain how you have applied this quote to the "front" and "back" of a photon and how you chose front-positive back-negative.
ETA: Also, why are you referring to a specific revision of a WP page with an edit that has been removed. I'm not able to find any substance to what the WP editor added which was later removed. Can you link to an actual source? |
31st July 2014, 01:01 PM | #2544 |
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Still a very simple answer for a very easy question: there are plenty of incompetents who sew words together that were never sewn up that way by real scientists. But because they have seen some words and have a vague knowledge of what the words mean out in the normal not very scientific world, they go on to misuse those words (use them in non-scientific ways /with non-scientific meanings to explain how they think real things and real science works). They have no clue as to how to develop and test hypotheses, a high school regular class knowledge of testing a hypothesis and no idea of the complexity involved in truly doing the research to verify that a hypothesis is verified or not verified. How can they, they are trying to mix writings with each other, not trying to actually perform the necessary experiments. They are doing nothing more than science by text borrowing and rearranging. Not science, just old fashioned and completely irrelevant word games. OR: Q: Why is there so much crackpot science? A: Because there are so many crackpots.
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31st July 2014, 03:26 PM | #2545 |
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Yep, it's really bizarre. An anonymous Spanish IP address adds one sentence of nonsense to a stub of a Wikipedia page. Four edits later someone removes it. For the year it was up there it was practically a case study of why Wikipedia is a complicated reference source for the unwary. But to mine this of the past-versions log and treat it as a citation ... well, if you go looking for nonsense you can find it.
It's particularly amusing to see anonymous deleted wikicruft quoted as a source, given that Farsight's usual weapon is "argument from authority"; he acts as though any Einstein quotation automatically defeats any subsequent research result. I'm sure we can find a deleted Wikipedia edit that states clearly that Einstein was a reptoid. Irrefutable, really. |
31st July 2014, 08:14 PM | #2546 |
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Here's an example from one of Einstein's pop-science lectures that Farsight cited earlier today:
Originally Posted by Einstein
I'm interested in both (studying Einstein and studying relativity theory). My interest in Einstein was rekindled by Farsight's dogmatic insistence that Einstein's general theory of relativity is quite different from what is taught by modern textbooks. Farsight's wrong about that, but seeing the equivalence between Einstein's presentations and that of (for example) Misner, Thorne, and Wheeler (MTW) does require some mathematical sophistication. Einstein's early papers on general relativity were fairly rough, and a few of his earliest contain outright errors. Einstein had fixed most of these errors by 1916, in Die Grundlage der allgemeinen Relativitätstheorie, but some notations of that paper are so different from modern notation that reconciling its equations with those of MTW isn't always obvious. Five years later, Einstein delivered the lectures collected in The Meaning of Relativity. Those lectures mostly follow the structure of Die Grundlage der allgemeinen Relativitätstheorie, but Einstein had modernized his notation to such an extent that the correspondence between his 1921 equations and those of MTW or Weinberg is far easier to see. I agree that Einstein's prose is often more confusing than his equations, partly because Einstein wasn't consistent. Consider, for example, the question of what Einstein meant by "the gravitational field". In one paper he refers to Christoffel symbols as "the components of the gravitational field". In another lecture he refers to components of the pseudometric tensor as "the gravitational potentials". In 1916, Einstein uses the word "curvature" only when talking about the curvature of light within a gravitational field. By 1921, Einstein uses the word "curvature" only when talking about the Riemann curvature tensor and its contractions. I think it's fair to say that Einstein's notation and terminology changed as much in those five years as those notations and terminologies would change in the next fifty (after which, MTW's Gravitation devoted two red pages of front matter to summarizing 37 notational conventions). It's easy to understand how crackpots are confused by all this. |
31st July 2014, 08:49 PM | #2547 |
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No debate known by this person who studied relativity theory many many years ago!
And can read Wikipedia: Propagation of light in non-inertial reference frames |
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31st July 2014, 09:04 PM | #2548 |
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Sorry, Farsight, but:
Being wrong about what Einstein in a speech puts you on the crackpot side of the fence. Relying on Einstein quotes rather then modern textbooks puts you on the crackpot side of the fence. Displaying the inability to get past the third equation in an Einstein paper and thinking that you know about GR puts you on the crackpot side of the fence. Then there are the many other indictors of which side of the fence you are in the Relativity+ thread (e.g. the cartoon of the EM field around a particle that just adds up the E field from a particle + the B field from a current!) Evidence for a position consists of experimental results and observations and citations of "rigorous analysis of the mathematics". IOW: Evidence for a position consists of citations to both the experimental and theoretical scientific literature. Russ Dill is talking about a strange new idea from you: "The front portion of a photon is a little like a partial positron, the back is a little like a partial electron" and the lie about "But the main point is that photons interact with photons, and QED doesn't cover it". The point is that QED does cover photon-photon interactions and says that photons do interact as you cited Two-photon physics
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1st August 2014, 03:59 AM | #2549 |
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1st August 2014, 06:19 AM | #2550 |
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No, because of the tautology described by Magueijo and Moffat in http://arxiv.org/abs/0705.4507 . Imagine you get down near the floor, then you define your second as the duration of 9192631770 periods of radiation going past you. Then you define your metre as the length travelled by this radiation in 1/299,792,458th of a second. You've used the motion of light to define your second and your metre. Then you use them to measure the motion of light. Hence the tautology, wherein you always measure the local speed of light to be 299,792,458 m/s.
You get up near the ceiling and repeat. Again you're using the second and the metre defined using the motion of light, to measure the motion of light. Again you measure the local speed of light to be 299,792,458 m/s. But one 299,792,458 m/s isn't the same as the other. The speed of light at floor level is slower than up at the ceiling, hence the second is bigger down there. The metre is the same because the slower light and the bigger second cancel each other out. Yes. See the Wikipedia article on gravitational time dilation. "The speed of light in a locale is always equal to c according to the observer who is there. The stationary observer's perspective corresponds to the local proper time. Every infinitesimal region of space time may have its own proper time that corresponds to the gravitational time dilation there, where electromagnetic radiation and matter may be equally affected, since they are made of the same essence[5] (as shown in many tests involving the famous equation E=mc²)". The points to note are the infinitesimal region and the same essence. The room you're in is not an infinitesimal region. The same essence means you're affected just like light. When light goes slower so do you, so you don't notice it. |
1st August 2014, 06:58 AM | #2551 |
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No. It's just something that came up in the conversation. We were talking about gamma-gamma pair production, and some Wikipedia guy had said something about half wavelength is a positive charge and the next half wavelength is a negative charge. I don't go round saying a photon is half a positron followed by half an electron.
Originally Posted by W.D.Ciinger
Originally Posted by Reality Check
"Einstein talked about the speed of light changing in his new theory. In his 1920 book "Relativity: the special and general theory" he wrote: "... according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity [...] cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity [Einstein means speed here] of propagation of light varies with position." This difference in speeds is precisely that referred to above by ceiling and floor observers.". |
1st August 2014, 11:05 AM | #2552 |
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I didn't say anything about positrons or electrons. You said that 'The front portion of a photon is a little like a partial positron, the back is a little like a partial electron.' I'm trying to find out why you assigned "a little like a partial positron" to the front and "a little like a partial electron" to the back. It would seem that this would be arbitrary and if it were true, there should be an anti-photon that is "a little like a partial positron" in the back and "a little like a partial electron" in the front.
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1st August 2014, 11:51 AM | #2553 |
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It is hard to respond with anything but "lol". The complete rejection of using mathematics to support/refute arguments is stunning (on a certain nay-sayer's part).
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1st August 2014, 12:55 PM | #2554 |
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As a wave packet passes a particular point where there is no non-zero background field, the magnitude of the field briefly increases and then returns to zero. If I had to guess, I'd say that someone mistakenly conflated the idea of a negative rate of change with that of a negative charge.
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1st August 2014, 01:23 PM | #2555 |
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Actually, my guess was that someone saw a cartoon illustration of a wavepacket --- a little snippet of sine wave, maybe made of little arrows representing field vectors --- and saw that (in this particular cartoon) on one end of the packet the arrows were pointing up, and on the other end they were pointing down. The person says "OK, positive arrows on this end and negative arrows on this end" and thinks that means positive charge and negative charge.
Farsight himself has made cartoon-wave-interpretation mistakes---I forget the details and won't go hunting for the link. IIRC, he linked to a cartoon showing several sine waves at different frequencies; in the cartoon, the waves were all drawn at the same amplitude. He mistakenly thought this was evidence for some sort of constant-amplitude-vs-frequency effect in Nature and made some nonsensical claim for which that was the premise. |
1st August 2014, 01:31 PM | #2556 |
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1st August 2014, 01:54 PM | #2557 |
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It seems that this effect happens in a gravitational field:
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The above would hold even if the meter were still based on some length of platinum in Paris. So, it seems that there is no tautology: the velocity of light is constant in all frames in GR (just as in SR) as both time and space are transformed by the influence of gravity. |
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1st August 2014, 04:00 PM | #2558 |
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I think the "all frames in GR" part is a misleading generalization of what your cited paper claims:
Originally Posted by Richard J Cook
In SR, we speak only of inertial frames, and fall into the habit of dropping the "inertial" qualifier. In GR, inertial frames are rare. In GR, a frame is highly arbitrary. A GR frame (aka coordinate patch, map) can be any smooth mapping from an open subset of spacetime to R4. The coordinate velocities of light within a GR frame are therefore equally arbitrary. Your cited paper points out that a GR frame plus knowledge of the pseudometric tensor field's components throughout that frame allows the local velocity of light to be computed at any point of spacetime within the domain of the frame, and that this (often daunting) computation will result in the standard value c. In my opinion, that's not quite the same as saying the velocity of light is constant in all GR frames. |
1st August 2014, 05:07 PM | #2559 |
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I have assumed the phrase "the velocity of light is constant in all frames in GR" implies that c is being measured by someone in each frame. Is not the "distant observer" you refer to in some other frame? By frame in this context do we not mean some infinitesimal patch of spacetime? Perhaps I'm missing something.
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1st August 2014, 06:16 PM | #2560 |
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Disclaimer: I am not a physicist.
The highlighted question is key. The paper you cited uses the word "frame" three times, and I do think it's possible the author of that paper tends to think of frames as infinitesimal patches of spacetime. If so, then he's probably thinking of what MTW refer to as a "moving, infinitesimal reference frame, or tetrad" in sections 6.4 and 6.5. MTW section 6.3 introduces those sections by talking about the difficulty of understanding what might be meant by "the coordinate system of an accelerated observer". It took me a few years to figure out that some physicists' habit of talking about "the reference frame of an observer" as if it were well-defined was an artifact of the historical progression from SR to GR, and that the concept of an "infinitesimal reference frame" is mostly an artifact of (mostly futile) attempts to come up with a well-defined notion of an arbitrary observer's reference frame. See, for example, MTW section 13.6 on "The Proper Reference Frame of an Accelerated Observer". That section tells how to construct an extended (non-infinitesimal) "proper reference frame" but warns:
Originally Posted by Misner, Thorne, and Wheeler
Note, however, that a Schwarzschild coordinate patch is far from infinitesimal. Although it does not and cannot cover all of spacetime (despite crackpot claims that it does), a Schwarzschild coordinate patch does cover all of the (idealized) spacetime outside of a hypothetical black hole's event horizon except for those points that lie on the coordinate singularities of the space-like spherical coordinates. (We are also familiar with the crackpot consequences of failing to understand that the coordinate singularities at the event horizon are no more meaningful than coordinate singularities of spherical coordinates.) As I say, it took years for me to figure out that the notion of a reference frame in general relativity is best identified with the notion of a coordinate patch (aka map) in differential geometry. That's the notion of reference frame assumed by the FLRW metrics and by all of the standard metrics that generalize the Schwarzschild metric. That notion is not infinitesimal; for the spacetime manifolds of general relativity, a coordinate patch is defined on an open subset of spacetime. In practice, that open set is (implicitly) taken to be the largest connected open set that avoids the coordinate singularities of the pseudometric form. I think it's mostly a semantic question, and I think it's a dangerous question to try to answer because (1) there's more than one possible interpretation of "all GR frames" and (2) there's more than one possible interpretation of what is meant by "the velocity of light is constant" in a frame. For someone like me, who takes "all GR frames" to mean all possible maps of all complete atlases of all possible spacetimes and takes "the velocity of light is constant" within a frame to mean the coordinate velocity is constant throughout the frame, then "the velocity of light is constant in all GR frames" is trivially false. |
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