classical physics vs relativity: parallel electron beams

[Nereid]

Indeed. Perhaps. When the science has not been settled, there are contrary views among experts and those involved in the research.

Which leads, I think, to the question of how a TB Forum member goes about making decisions on topics like this (and the more general one in this post I'm quoting).

For example, without a good grasp of the relevant background math, how could anyone judge the merits, or non-merits, of what S. Crothers has written?

Another example: without a good understanding of the details of a 'bending of light by the Sun' experiment (or observation), how could anyone judge the merits, or non-merits, of Mermet's paper?

[solrey]

Or put another way...Without a good understanding of the details of the Electric Universe or Plasma Cosmology, how could anyone judge the merits, or non-merits, of those theories?

[Aristarchus]

Which leads, I think, to the question of how a TB Forum member goes about making decisions on topics like this (and the more general one in this post I'm quoting).

The papers I have linked and others on this board gives more than ample evidence that the TB Forum members make very valid points that are open to an objective inquiry. The fact that very recently the Plasma Universe has been accepted by The American Institute of Physics as a legimate field of physics demonstrates that there is some head way being made. We are now revisiting the genius of Nikola Tesla.

For example, without a good grasp of the relevant background math, how could anyone judge the merits, or non-merits, of what S. Crothers has written?

This is a subjective statment that stands behind an assumed authority, not an objective positing that attempts to dispute the specifics of what has been thus far discussed. It's an easy way out of engaging your fellow posters. Sydney Chapman's beautiful mathematical equations regarding magnetic storms and aurorae was finally more than ruled out more than thirty-years later in favor of the intuitive insights of Hannes Alfven. Empiricism ruled the day. Hey, one bitten, twice shy.

[Physicist]

Aristarchus - your misunderstanding is so severe that I can't resist one more post

Here's an excellent explanation of the relevant issue (emphasis is mine):

http://www.xs4all.nl/~johanw/PhysFAQ/Re ... light.html

Einstein went on to discover a more general theory of relativity which explained gravity in terms of curved spacetime, and he talked about the speed of light changing in this new theory. In the 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 of propagation of light varies with position. Since Einstein talks of velocity (a vector quantity: speed with direction) rather than speed alone, it is not clear that he meant the speed will change, but the reference to special relativity suggests that he did mean so. This interpretation is perfectly valid and makes good physical sense, but a more modern interpretation is that the speed of light is constant in general relativity.

The problem here comes from the fact that speed is a coordinate-dependent quantity, and is therefore somewhat ambiguous. To determine speed (distance moved/time taken) you must first choose some standards of distance and time, and different choices can give different answers. This is already true in special relativity: if you measure the speed of light in an accelerating reference frame, the answer will, in general, differ from c.

In special relativity, the speed of light is constant when measured in any inertial frame. In general relativity, the appropriate generalisation is that the speed of light is constant in any freely falling reference frame (in a region small enough that tidal effects can be neglected). In this passage, Einstein is not talking about a freely falling frame, but rather about a frame at rest relative to a source of gravity. In such a frame, the speed of light can differ from c, basically because of the effect of gravity (spacetime curvature) on clocks and rulers.

If general relativity is correct, then the constancy of the speed of light in inertial frames is a tautology from the geometry of spacetime. The causal structure of the universe is determined by the geometry of "null vectors". Travelling at the speed c means following world-lines tangent to these null vectors. The use of c as a conversion between units of metres and seconds, as in the SI definition of the metre, is fully justified on theoretical grounds as well as practical terms, because c is not merely the speed of light, it is a fundamental feature of the geometry of spacetime.

Like special relativity, some of the predictions of general relativity have been confirmed in many different observations. The book listed below by Clifford Will is an excellent reference for further details.

Finally, we come to the conclusion that the speed of light is not only observed to be constant; in the light of well tested theories of physics, it does not even make any sense to say that it varies.

While I'm sure you can continue the quote mining ad infinitum

It's not called "quote mining." It's called citing sources/references.

I'm curious as to YOUR opinion. Do you think that the speed of light is constant in GR? How would YOU define it?

I'm offering authoritative cited sources that appear to defy your previous comment (viz), "The gravitational field does NOT affect the speed of light - light always travels past any observer at the same speed c." My previous cited sources was from Warren F. Davis who obtained his PhD in Physics from M.I.T.

It's not for me to define, but for you to have an understanding of how this is actually understood in your field of physics. For example - here's more:

http://arxiv.org/PS_cache/math-ph/pdf/0 ... 0054v1.pdf

Three Tests of General Relativity via Fermat’s
Principle and the Phase of Bessel Functions

The slowing down of clocks in a gravitational field will result in an apparent reduction in the speed of light. Light will therefore travel at the phase velocity u(r) = c/η(r), rather than c, as it would in vacuum.

What you stated above, i.e., "The gravitational field does NOT affect the speed of light - light always travels past any observer at the same speed c.", is patently untrue. This is according to the GR theory.

So the question becomes, how is it that in your internet research you were able to find so many references to light slowing down in a gravitational field?

The answer is that in applications like gravitational lensing, an approximation to GR is made. The approximation is that curved space is treated as flat space, but with an effective refractive index derived from the Newtonian gravitational potential. Hence that pesky word "apparent" in your quote above. The abstract of that paper makes it clear that the author is working in that approximation from the beginning.

If an observer is in the geometry in question, he or she will certainly see light going by at speed c. Assuming of course that you define the speed of light in an appropriate coordinate-independent fashion.

In conclusion - I think that you're certainly guilty of quote mining, although you probably weren't aware of it. There is no way you could have known the context of your quotes without putting in a great deal more work.

I'll skip a response to the rest of your post - this discussion is nasty enough already

For example, without a good grasp of the relevant background math, how could anyone judge the merits, or non-merits, of what S. Crothers has written?

Another example: without a good understanding of the details of a 'bending of light by the Sun' experiment (or observation), how could anyone judge the merits, or non-merits, of Mermet's paper?

I was wondering that too. But I think the main motivation of our friend Aristarchus, as well as of the aforementioned authors, is to create the impression that there is some kind of controversy wrt these issues in GR. I don't think that's the case.

Now I really am going to do some work

Later.

[mharratsc]

I think we all bring a certain bias to the table...

Standard model proponents stand on the mathematics and corroboration of thousands of people over several decades to justify their stance.
EU/PC model proponents stand on the scalar nature of plasma physics and elecrodynamics, and the amazing similarities seen between cosmic phenomena and laboratory phenomena, and feel that empiricism guides them.

We can feel threatened by the differing opinions voiced by others, or we can see it as an engaging challenge to face! However, just because someone is 'challenging' us or our views most assuredly doesn't mean that we have to react negatively- that simply makes us appear insecure, and emboldens our opponents as though they have discovered a weakness in us. :\

In the end- it isn't being challenged that will have traumatized us, but rather it will be what we discover when Truth is finally revealed and we stand naked with our conceits- were we correct, or no? o.O

[Aristarchus]

The answer is that in applications like gravitational lensing, an approximation to GR is made. The approximation is that curved space is treated as flat space, but with an effective refractive index derived from the Newtonian gravitational potential. Hence that pesky word "apparent" in your quote above. The abstract of that paper makes it clear that the author is working in that approximation from the beginning.

First, that section you're re-quoting from the paper is not taken from the abstract of the paper, unless you're referring to something I cannot distinguish from your post as not provided by you. In other words, you need to be clearer. Second, the point I was making was in refutation of your generalization to the following statement by you (viz), "Ugh! Now it becomes clear where his misunderstanding lies. The gravitational field does NOT affect the speed of light - light always travels past any observer at the same speed c."

Here is what the author also wrote:

If a light signal is sent from the earth, located along the x-axis at −xE, to Venus, which is located behind the sun at xV , the light ray will be bent as it passes the gravitational field of the sun. Clocks will be slowed down and the time it takes the ray to bounce off Venus’ surface and return to earth will be longer than if the sun were not present.

Let's not lose sight of the fact that you were making this statement to reject the positing of Hynecek in his paper that I linked, which you before made a blanket statement that was a follow up for what you already precluded as him not being adept in the field of physics - although he was an assistant professor in physics at CTU and awarded with three distinct recognitions from NASA. Obviously, Hynecek is absolutely correct in the statement he put forth, which you attempted to refute, against the fact that Hynecek is beyond question making it in light of the detail: "So, it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]."

Found at the following, which I already quoted: http://www.physlink.com/Education/AskExperts/ae13.cfm

You know, the PhD in Physics from M.I.T. guy I had already pointed out to you.

Me thinks you obfuscate a bit too much. I think we're heading in the direction now where you attempt to make Hynecek's argument for him, without ever deferring to his credentials, or the specifics of his paper.

[Nereid]

Or put another way...Without a good understanding of the details of the Electric Universe or Plasma Cosmology, how could anyone judge the merits, or non-merits, of those theories?

They can't (or couldn't).

[Nereid]

Which leads, I think, to the question of how a TB Forum member goes about making decisions on topics like this (and the more general one in this post I'm quoting).

The papers I have linked and others on this board gives more than ample evidence that the TB Forum members make very valid points that are open to an objective inquiry.

So, and I hope I'm not putting words in your mouth (I'm sure you'll correct me if I do), they judge on the basis of objective evidence.

The fact that very recently the Plasma Universe has been accepted by The American Institute of Physics as a legimate field of physics demonstrates that there is some head way being made.

I have no idea what this means, especially the bit about "the Plasma Universe" (capital P, capital U); would you say a bit more please?

We are now revisiting the genius of Nikola Tesla.

What does that have to do with either the Plasma Universe or the AIPS?

For example, without a good grasp of the relevant background math, how could anyone judge the merits, or non-merits, of what S. Crothers has written?

This is a subjective statment that stands behind an assumed authority, not an objective positing that attempts to dispute the specifics of what has been thus far discussed.

I don't follow; for starters, what you quoted is a question (not a statement) - and objectively so.

For seconds, if you assume authority, that's something subjective (i.e. created by you), not objective, right?

For thirds, I did not intend to "dispute" any "specifics", whether they have been thus far discussed or not.

For fourths, nearly all the material written by S. Crothers that I have read concerns General Relativity (GR), and is based on his views of some math-based aspects of GR.

It's an easy way out of engaging your fellow posters. Sydney Chapman's beautiful mathematical equations regarding magnetic storms and aurorae was finally more than ruled out more than thirty-years later in favor of the intuitive insights of Hannes Alfven. Empiricism ruled the day. Hey, one bitten, twice shy.

I'm afraid you've completely lost me; are you saying we should all ignore the parts of Crothers' published material which include mathematical equations (whether beautiful or not)? If not, what are you saying?

[Nereid]

Light Deflection Near the Sun's Limb: Refraction by the Solar Atmosphere

Light refraction by the Sun's atmosphere is calculated.As detected from the Earth, the refraction can deflect a light ray emitted from the Sun's limb by 13'' or a starlight ray grazing the solar limb by 26'', an effect 15 times larger than the gravitational deflection.

Now, the point is, if anything is being overlooked or unaccounted for, we might find there's a plasma refraction that's the same as the alleged gravitational deflection.

I've now read this.

Would you mind saying a few words on why you think this is relevant to the specific question of what the observations of the bending of light by the Sun are?

Also, isn't it more important that models involving plasma refraction account for the objective, published, observational results (than whether they match what GR predicts)?

[Aristarchus]

I have no idea what this means, especially the bit about "the Plasma Universe" (capital P, capital U);

Are you serious? You're now digressing to discuss the proper use of capitalizations? More amusing is that you're playing this game as if it actually makes a difference in your understanding of what has been posted.

It's my understanding that the term Plasma Universe was coined by Hannes Alfven, and depending on the citation style that is used (APA, MLA, AMA, Chicago, etc) it isn't written in stone on how to use capitalization - and even that is subject to change over time.

What next? We're going to discuss the use of capitalization use in the English as opposed to the German?

would you say a bit more please?

Nah. I'm comfortable with what I documented on this thread and where I'm at in the discussion. I'll just sit back and be entertained by reading the barrage of questions you throw out in an attempt to somehow legitimize your responses without ever directly relating to the material.

For now, my focus is on how these two statments will comport themselves:

"Ugh! Now it becomes clear where his misunderstanding lies. The gravitational field does NOT affect the speed of light - light always travels past any observer at the same speed c."

As oppsed to ...

"So, it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]."

[Physicist]

Aristarchus - if you took the time to learn the subject you wouldn't have to make these little decisions based on competing arguments from authority

Let's put your quote in context:

The result is _not_ the same in general relativity. In general relativity, the statement becomes that the speed of light is the same (i.e., good old 'c') for all observers in _local_ inertial frames.

Local inertial frames in general relativity are just those frames of reference in which the observer is in gravitational free fall. A fancy way of looking at it is that the _local_ frame of reference of a free falling observer corresponds to a small patch of _flat_ spacetime tangent to the globally curved spacetime. As long as the observer confines measurements to a small enough local region, the approximation provided by the small tangent patch of flat spacetime can be made to be an arbitrarily good approximation to the true spacetime, which is actually curved in the main. The speed of light in flat spacetime is, of course, the usual value of c.

For example, if one had a closed laboratory in orbit (i.e., in free fall) around the earth and one did an experiment inside that laboratory to measure the speed of light, one would get the usual published value of c. All such observers would get one and the same value for c.

If, however, the distance through which the light travelled in the course of measuring its speed was too great, the deviation of the reference frame from being 'flat' would become apparent. That is, gravitational effects would begin to become apparent.

So, it is absolutely true that the speed of light is _not_ constant in a gravitational field

In the first two paragraphs he gets it absolutely right. In the second to last paragraph, his observer is not making an accurate measurement of the speed of light, precisely because he is not making a local measurement. It is this INCORRECT value for the speed of light that is not constant. Otherwise we have a contradiction between his first and last paragraphs.

[mharratsc]

It really seems that this argument has digressed to an argument for argument's sake now. :\

What exactly IS the point trying to be made here? It seems as though there is an argument about whether Relativity calls for a static vs dynamic 'speed of light'.

Since it's known that light can be slowed almost to a stop by the medium of its conduction, I'm confused as to why anyone would belabor it further? o.O

[Aristarchus]

Aristarchus - if you took the time to learn the subject you wouldn't have to make these little decisions based on competing arguments from authority

Well, it appears I'm in good company, since you also question the knowledge base of someone that taught physics at CTU, and was dintinguished with three distinct accolades from NASA.

You stated previously:

Physicist wrote:
"Ugh! Now it becomes clear where his misunderstanding lies. The gravitational field does NOT affect the speed of light - light always travels past any observer at the same speed c."

Wrong. The gravitational field does effect the speed of light.

"So, it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]."

It is this INCORRECT value for the speed of light that is not constant. Otherwise we have a contradiction between his first and last paragraphs.

You didn't even post the entire last paragrpah. Shall we?

So, it is absolutely true that the speed of light is _not_ constant in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]. If this were not so, there would be no bending of light by the gravitational field of stars. One can do a simple Huyghens reconstruction of a wave front, taking into account the different speed of advance of the wavefront at different distances from the star (variation of speed of light), to derive the deflection of the light by the star.

Reading emphasis, mine, it's more than apparent that Hynecek was aware of this when he made his statement, unless, of course, you want to question the credentials of a Phd graduate from M.I.T., i.e., Warren Davis.

It really seems that this argument has digressed to an argument for argument's sake now.

I apologize, mharratsc, but it appears beyond the pale that when I post something, e.g., from a distinguished person, such as, Hynecek, the responses from Physicist are on the level of (viz).

Without having checked through all his math, my initial impression is that this one is pure pseudoscience.

Is it your opinion that because you can find someone with any given crackpot opinion on the internet, that makes the relevant science controversial?

[Physicist]

Aristarchus - I notice that you didn't respond to my points - however if you do so I'd still be delighted to discuss the speed of light in GR with you.

However I did look up the Hynecek paper where the derivation of his metric was supposed to be -

http://www.wbabin.net/physics/hynecek5.pdf

and found that it was NOT there. Perhaps this is an honest mistake.

Nevertheless I read the paper above quite closely, and again in my opinion it is pure pseudoscience. The author presents an incorrect derivation of the energy stored in the electric field inside a moving parallel plate capacitor. Having reached his incorrect result, he reaches the startling conclusion that gravitational mass is not the same as inertial mass. The correct conclusion would have been that he used the wrong formula.

The problem is that he hasn't transformed the electromagnetic energy density in a covariant way. The correct way to do that has been discussed many times in the literature - for example here:

http://muj.optol.cz/~richterek/data/med ... er1958.pdf

If you don't do it correctly, you end up with what's called the "Trouton - Noble paradox" - which asserts that a parallel plate capacitor has a torque on it that depends on your frame of reference. If you do it correctly, you get the expected result - from which (presumably) Mr Hynecek would conclude that gravitational mass and inertial mass are the same after all.

I suspect that if Mr Hynecek had tried to publish this one in a real journal, the referees would have been good enough to point out that his problem has been thought about, solved (correctly) and written up.

There's also some funny stuff like "millions of dollars are spent every year to support the activities based on the obviously flawed theory" on which I'll refrain from passing comment

[mharratsc]

I'm a little confused by this experiment. They're talking about a pair of charged plates that are allowed to freely spin. If current is induced to flow (i.e.- that suspended capacitor is allowed to become a part of a circuit with the Earth) then is it not going to start spinning from Lorentz force, behaving as a homopolar motor?