Why is there so much crackpot physics?

[Kwalish Kid]

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."

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.

 

[Perpetual Student]

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.

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?

 

[RussDill]

There aren't any. What you found related to gamma gamma pair production where the Wikipedia article used to say this:

"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".

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?

 

[fuelair]

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.

 

[ben m]

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?

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.

 

[W.D.Clinger]

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.

Here's an example from one of Einstein's pop-science lectures that Farsight cited earlier today:

The first stage, the special theory of relativity, owes its origin principally to Maxwell's theory of the electro-magnetic field. From this, combined with the empirical fact that there does not exist any physically distinguishable state of motion which may be called "absolute rest", arose a new theory of space and time.

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.

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.

 

[Reality Check]

You have yet to demonstrate that anyone who has studied relativity theory believes that there is something to be debated about the speed of light in the theory.

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

 

[Reality Check]

No, saying Einstein was wrong is the crackpot indulgence. And I'm on the right side of that fence.

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

From quantum electrodynamics it can be found that photons cannot couple directly to each other, since they carry no charge, but they can interact through higher-order processes.

 

[Kwalish Kid]

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

I think I'd prefer it if you reference an older edit of wikipedia.

 

[Farsight]

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?

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.

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?

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.

 

[Farsight]

Please explain how you have applied this quote to the "front" and "back" of a photon and how you chose front-positive back-negative.

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.

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...

I'm not. Einstein really did say the speed of light varies with position. He really did describe a gravitational field as inhomogeneous space. But many physicists today will tell you that the speed of light is absolutely constant, And they will confuse space and spacetime. Then they'll wax lyrical about curved space. Or moving through spacetime. Or how the principle of equivalence is sacrosanct, forgetting that it applies to an infinitesimal region. A region of zero extent.

Sorry, Farsight, but: Being wrong about what Einstein in a speech puts you on the crackpot side of the fence.

I'm not wrong. I'm on the right side of the fence. The same side as this Baez article:

"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.".

 

[RussDill]

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.

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.

 

[Almo]

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).

 

[ctamblyn]

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.

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.

 

[ben m]

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.

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.

 

[ctamblyn]

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.

Oh yes, the "common amplitude" debacle. This was one of those posts. Unfortunately the link to the original image is now dead, but it was something like this.

 

[Perpetual Student]

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.

It seems that this effect happens in a gravitational field:

Gravitational Space Dilation

Richard J. Cook

We point out that, if one accepts the view that the standard second on an atomic clock is dilated at low gravitational potential (ordinary gravitational time dilation), then the standard meter must also be dilated at low gravitational potential and by the same factor (gravitational space dilation). These effects may be viewed as distortions of the time and length standards by the gravitational field, and measurements made with these distorted standards can be "corrected" by means of a conformal transformation applied to the usual spacetime metric of general relativity.

LINK

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.

 

[W.D.Clinger]

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.

I think the "all frames in GR" part is a misleading generalization of what your cited paper claims:

The notion of gravitational space dilation derives from a single observer’s view that, when a distant observer’s standard time interval is dilated by a gravitational field, his standard length must be dilated as well and by the same factor. If this were not so, the distant observer could not understand how the local observer obtains the invariant value c for the locally measured light speed.

That's true enough, but the fact remains that the frame chosen by the single observer is probably showing a coordinate velocity of light other than c at the distant observer. So I don't think you should say the velocity of light is constant within the frame.

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.

 

[Perpetual Student]

I think the "all frames in GR" part is a misleading generalization of what your cited paper claims:


That's true enough, but the fact remains that the frame chosen by the single observer is probably showing a coordinate velocity of light other than c at the distant observer. So I don't think you should say the velocity of light is constant within the frame.

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.

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.

So, if an observer at any point in spacetime will compute the standard value of c, what else might we mean by saying "the velocity of light is constant in all GR frames."? Is this merely a semantic question? Again, I may be missing something (or lots of things).

 

[W.D.Clinger]

Disclaimer: I am not a physicist.

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.

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:

Only a foolish observer would try to use his own proper reference frame far from his world line, where its grid ceases to be orthonormal and its geodesic grid lines may even cross!

Consider, for example, a Schwarzschild coordinate patch. That's the proper reference frame for an observer observing a spherically symmetric, non-rotating and uncharged star or black hole from infinitely far away, and serves as an excellent approximation to the proper reference frame for observers observing from a great distance. Thanks to some of the crackpot physics we've discussed in this thread, we are familiar with the folly of trying to use that reference frame to reason about physics near the event horizon of a black hole.

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.

So, if an observer at any point in spacetime will compute the standard value of c, what else might we mean by saying "the velocity of light is constant in all GR frames."? Is this merely a semantic question? Again, I may be missing something (or lots of things).

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.