# Wikipedia talk:WikiProject Physics/Archive November 2010

## banned user

This banned user has continued to edit science articles since his ban some 3 years ago. Some recent contributions by him are listed here and here and here and here and here and here and here and here and here (a small sample). He has been subjected to a recent 'hardblock' but I suggest project members should become familiar with his interests, methods etc so as to keep an eye on his antics as he is likely to go on reinventing himself indefinitely. McZeus (talk) 02:02, 1 November 2010 (UTC)

I don't see any problems with Rbj editing science articles. I think he was blocked a long time ago for incivily on some gay marriage talk page but I don't see the logic of keeping him banned. Now, there are rules on Wikipedia for dealing with these sorts of issues, but it has become clear to me in recent days that some problems/anomalies I've experienced here some time ago were not an accident, there is a systemic problem with the Arbitration system here. See e.g. here, this Wiki user quite a respectable person who in real life is an atmospheric science professor with hundreds of publications, certainly not a "usual suspect" whose statements you would have to take with a pinch of salt.

I have therefore decided that I will no longer recognize the validity of the blocks/topic bans on people like Rbj, William Connolley, Brews Ohare, Likebox, Polargeo, etc. etc. etc. etc. I encourage all of them to ignore any bans/blocks as that only poses a problem for the corrupted processes that lead to these people being bocked, which can only be a good thing. Count Iblis (talk) 18:53, 1 November 2010 (UTC)

Of course if they actually do what you suggest, this will just further confirm the legitimacy of their blocks in the eyes of quite a few and meanwhile people like scibaby will see this sockpuppetry as justification for their sockpuppetry and proof those who've been active in blocking them are no better. Nil Einne (talk) 23:31, 1 November 2010 (UTC)
Scibaby is happy as things are right now. William was judged to have violated his topic ban for merely pointing to a Scibaby like edit, see here. The edit in questions was only reverted because William reported it (it takes time for the community to take over the task of patrolling all climate science articles). William was reported at AE by an editor who, while not a Scibaby sock, could easily pass for Scibaby based on his editing record here. Then William gets blocked for two weeks and the two problematic editors are still free to edit here.
It may be that William will ask for clarification and the Arbitrators will be reasonable and e.g. rule that if William notes that a Scibaby-like edit hasn't been reverted in, say, 12 hours time, he is allowed to post a diff on his talk page. But that will only happen as a result of the bad block and the fallout that triggered.
And all this is only one of the problematic issues that have surfaced since the end of the CC case. Count Iblis (talk) 00:10, 2 November 2010 (UTC)

Bans that can't be enforced should be lifted and I don't oppose lifting the ban on Rbj if it can't be enforced. He does some good work here whether banned or not - he can always be relied on to revert bad edits. On the other hand, others are capable of doing that too and often he reverts even good edits for personal reasons or because he feels ownership of some articles. I don't think his disappearance from the scene would amount to a real loss for WP. His bullying, his subterfuges, his misrepresentation of other viewpoints, his edit warring and incivility are certainly not needed and his disappearance in that case would represent a big plus for WP. I don't edit science articles any longer and I posted this information for others here to use as they see fit. I'm done with this issue. McZeus (talk) 01:01, 2 November 2010 (UTC)

I agree. See The Governance Model of Wikipedia. —Moulton 06:03, 2 November 2010 (UTC) —Preceding unsigned comment added by 68.160.163.173 (talk)
I respectfully request that any extended discussion about how Wikipedia is or should be governed be moved to User Talk or another relevant venue. --Christopher Thomas (talk) 06:10, 2 November 2010 (UTC)

## BRST Formalism

A articles for deletion discussion ended with the conclusion that BRST formalism should be merged to BRST quantization. I've merged all that I actually understand (two entire sentences!!), but there is still quite a bit to do. We need some real physicists to merge these together to BRST quantization. D O N D E groovily Talk to me 01:37, 2 November 2010 (UTC)

I'm inclined to think that there is not much else that needs to be done. Xxanthippe (talk) 01:42, 2 November 2010 (UTC).

## Grashof number

I think it's important to mention Bejan's definition of Grashop number. In his book Convection Heat Transfer, Bejan argues that Grashof number is not the ration of the Buoyancy to viscous forces, he says that based on that definition of Grashof number, air, which has a Gr of 10^8-10^10 has viscous forces neglegible in comparison with body force, which is not true since the Prandtl number is almost 1 and hence using his scaling analysis there will always exist a balance between interia and buoyancy as well as friction and buoyancy. According to him the meaning of Gr is purely geometric and is scaled as wall height divided by Wall shear layer thicknes.

Michael1408 03:07, 2 November 2010 (UTC) —Preceding unsigned comment added by Michael1408 (talkcontribs)

## Edit war at Absolute zero / Absolute hot

Me and another editor are edit warring at Absolute zero and Absolute hot. Some help would be appreciated. 07:29, 2 November 2010 (UTC)

Kbrose (talk · contribs) and you have not discussed your dispute on the talk pages and I find it hard to read the diffs in the histories. So what is the essence of your disagreement? JRSpriggs (talk) 14:35, 3 November 2010 (UTC)
It's probably best to take "encyclopedic or not" out of the equation in these discussions :) As far as the physics is concerned, temperature is the reciprocal of dLog(Omega)/dE. If you have a system that can hold a maximum amount of energy in a particular state then Omega will be 1 for that state. So, Omega will reach some maximum at some intermediary E, at that point you thus have that dLog(Omega)/dE = 0, so the temperature will be singular at that point. It jumps from positive infinity to negative infinity and it stays negative for larger E. I think this is simple enough to be included in the article... Count Iblis (talk) 15:01, 3 November 2010 (UTC)
It seems mostly resolved now. 15:14, 3 November 2010 (UTC)
I don't see how it's resolved. Kbrose's version was still in place. I have reverted to your version.
I'll summarize here: Kbrose's explanation is pretty much illegible. It goes as follows:
However, some spin systems achieve states of higher order by the process of population inversion when excited by electromagnetic radiation. The temperature function in such cases exhibits a singularity, approaching positive infinity and abruptly switching to negative infinity before asymptotically converging towards zero temperature in the negative domain.
What the "temperature function" is is not explained (function of what?). More importantly, negative temperature is not limited to "spin systems"; it occurs in any system in which adding internal energy reduces entropy. The system of excitations of electrons in a lasing medium is at negative temperature, as I understand it, for the very same reason.
Please also take a look at signed zero, where Kbrose has also attempted to water down the very clear statement from a very standard source, Kittel and Kroemer's Thermal Physics. --Trovatore (talk) 09:16, 4 November 2010 (UTC)

## Planetary Orbits

Planetary orbits is a topic which seems to cause alot of confusion. I found this reference here on the centripetal force article. [1]. It's called the 'Complete Idiot's Guide to Physics'. The author seems to think that one component of gravity acts to change the direction of a planet whereas another component acts to speed it up along its path. In actual fact, gravity only ever acts radially, and in doing so, it may or may not change the speed of a planet. It can of course contribute to an increase in speed in the radial direction, but the overall increase in speed in a non-circular planetary orbit comes from a combination of gravity and one of the transverse inertial forces. It would strike me that this author is totally confused.

There is no splitting of the gravity force into two components, one of which causes a change in speed and one of which causes a change in direction. Orbits aren't calculated on that kind of thinking. Orbits are calculated on the basis of a transverse equation and a radial equation. The two transverse inertial forces cancel out mathematically leading to Kepler's law of areal velocity and an associated angular momentum constant. This constant can then be used in the radial equation, and the radial equation is solved to yield a general solution of conic orbits. That means ellipses, hyperbolae, or parabolae, depending on initial conditions, with the circle being a special case of the ellipse. This highlights the problem of using modern sources. David Tombe (talk) 01:04, 5 November 2010 (UTC)

The only confusion here seems to be yours. Orbits can be calculated in various different ways. Polar coordinates (around the center of mass) are convenient when trying to solve the 2-body problem analytically, in this case the gravitational force only acts radially. Other approaches are however equally valid. Since the gravitational force (like any force) is a vector it can be decomposed in any way is deemed convenient. For example, in the way done in the source, there is nothing wrong with that at all.TimothyRias (talk) 02:11, 5 November 2010 (UTC)
There is nothing wrong with the decomposition of gravity into two components. Besides, "The two transverse inertial forces" makes no sense as no one calculates the orbit in a noninertial frame.--Netheril96 (talk) 03:04, 5 November 2010 (UTC)
@David Tombe: The article mentioned does not talk about circular motion. Both for elliptical and parabolic motions the focal point of the curve (that is where the center of gravity sits, e.g. the sun) and the center of the local curvature do not coincide. Although the sun's gravitational force on e.g. Mercury always points to wards the sun, only one component is needed to keep Mercury on its local curvature whereas the remaining component speeds him up or slows him down. Why else would Mercury be faster at the perihel than at the aphel of its path. --Dogbert66 (talk) 09:13, 5 November 2010 (UTC)

You all seem to be overlooking three points,

(1) The source (Idiot's Guide to Physics) was supposed to apply to the central force orbit scenario, but in actual fact it deals with the simplistic case at the Earth's surface where we treat gravity as a downward vertical force.

(2) And yes, gravity can indeed be resolved into components. But it is gravity itself that is the centripetal force. We cannot deem one component of gravity to be a centripetal force and the other component not to be. In the simplistic Earth's surface scenario described in the source, we have a gravitational force acting downwards. And yes, we can resolve it into two components. But the only change of velocity is in the vertical direction. We cannot deem one of the components to be a centripetal force and the other component to be causing a change in the speed.

(3) Gravity acts towards the focus of the conic section. The simplistic Earth's surface scenario is merely an approximation for a section of a Keplerian ellipse. The centripetal force is acting towards the focus of the ellipse, which in this simplistic case means downwards. There is no centripetal force acting at right angles to the direction of motion of the trajectory. David Tombe (talk) 10:14, 5 November 2010 (UTC)

The confusion appears to be about the meaning of tangential/radial: they can mean either "perpendicular/parallel to the line joining the star and the planet" or "parallel/perpendicular to the planet's instantaneous velocity". (The two definitions only agree at the apsides.) It is true that the gravitational force is entirely radial according to the first meaning, but the book you're citing is using the second meaning. A. di M. (talk) 14:12, 5 November 2010 (UTC)

A. di M., Yes indeed, the source (Idiot's Guide) does not apply to the situation which it was supposed to be applying to in that section at centripetal force. The source was supplied in relation to the central force problem, whereas, just as you say, it is actually talking about the simplified case in which gravity is a vertically downward force, and in which the horizontal speed and the upward centrifugal force are negligible. So let's now concentrate on the example in the source. We have a downward force of gravity. This is the only force that is involved in making the speed of the projectile faster, yet the author claims that the increase in speed is being caused by a tangential force which is a component of the gravitational force. That is not true. The speed increase is exclusively being caused by the total downward gravitational force which is causing an increase in the vertical component of the projectile's velocity. And the other component of gravity perpendicular to the projectile's motion is not a centripetal force and it is not acting towards any centre. This author has split gravity into two components, which in itself is not a problem, but then he has ascribed a separate physical role for each of the two components. That is where he goes wrong. David Tombe (talk) 14:27, 5 November 2010 (UTC)

When the projectile is at the top, the derivative of its speed is zero, as gravity has no component along the direction of motion at that point. The derivative of the speed is equal to the component of acceleration along the direction of the velocity, whatever it's caused by: that's just kinematics. A. di M. (talk) 15:43, 5 November 2010 (UTC)

A.diM., I see now what has happened. In Newton's time it was assumed that a centripetal force acted towards the physical origin of the rotating system and that gravity was a centripetal force. But now they are using normal and tangential unit vectors, and centripetal force has been re-defined as being the inward force acting in the normal direction to a motion. Such a system doesn't necessarily have a fixed origin, and as such it can lose synchronization with the physical origin of that system. Centripetal force in a Keplerian orbit can then become merely a component of gravity, as opposed to gravity itself. In my view, this concept of centripetal force loses the physical connection with cause and effect, and I would imagine that it would be very awkward trying to express Kepler's laws in such a system without the focus of the ellipses being the origin. But that is my own view. Having now studied it all more carefully, I am in agreement with you that it nevertheless gives a correct mathematical description of the motion. On the centripetal force article, it would be helpful if a distinction were to be made between these two concepts of centripetal force. That is (1) a force acting towards the centre of a rotating system, such as the focus in a Keplerian orbit, or the pole around which a swinging rope is attached, and (2) a force which acts at right angles to the direction of motion of an object, causing its path to curve. The two concepts can of course overlap, but it seems that clarification of the two definitions needs to be made for cases when they don't overlap. David Tombe (talk) 23:40, 5 November 2010 (UTC)

## Stern-Gerlach Experiment Results Inaccuracy

I believe the description at the top of Stern-Gerlach_Experiment is inaccurate. I've explained my proposal and reasoning and provided secondary references in the talk page for that article. To summarize, though, the existing description perpetuates the misunderstanding that the Stern-Gerlach experiment is a demonstration of spin quantization that is known from other phenomena and not, as it was, a demonstration of a separate quantum phenomena: the quantization of the *projection* of the angular momentum vector of a particle onto a coordinate axis parallel to an applied magnetic field. This is sometimes called "quantization of space." In any case, this is a significant difference from the current article and I would like to propose it be reviewed by this group. Porcelain mouse (talk) 18:52, 5 November 2010 (UTC)

You will have to produce sources for your arguments. Xxanthippe (talk) 21:57, 5 November 2010 (UTC).
He said that he provided references in the talk page thread. Checking, this is at Talk:Stern–Gerlach experiment#Description Inaccurate. --Christopher Thomas (talk) 22:22, 5 November 2010 (UTC)

## Heim theory (again)

My feeling, per my comments User talk:Terra Novus#Links to Heim theory with regard to other articles (diff hardlink), is that Heim theory is not notable enough to be mentioned at that article and that template (which discuss ToE options and standard model extensions that appear in mainstream literature, for the most part). That said, a) I could be wrong, and b) I might count as "involved" at this point, so additional eyes/opinions would be handy. --Christopher Thomas (talk) 07:04, 24 October 2010 (UTC)

I agree, a second opinion on the issue would be helpful. I have my rationale for including the template and link in the article at Talk:Heim theory...--Novus Orator 03:28, 7 November 2010 (UTC)

## Faster-than-light

A prolific anon has (re-)surfaced at Talk:Faster-than-light, restarting years-stale arguments, and mostly demonstrating that they don't grasp several of the concepts involved. I've attempted to consolidate their additions into a new thread (leaving the ones from a 2010 thread in place), and have set up Miszabot to archive anything older than 6 months. That said, I expect lots of further traffic before the dust settles. --Christopher Thomas (talk) 22:25, 5 November 2010 (UTC)

In order to avoid needles dust, in case of talk page abuse, one should not engage in any technical discussions, but just point to the talk page guidelines, suggesting the reference desk, and giving formal warnings on the user talk page. I have given a friendly first level chat-template warning. DVdm (talk) 23:33, 5 November 2010 (UTC)
I've found that it's usually faster just to answer the question being asked, with talk page guidelines being brought out only after the first few "ask for more details elsewhere" statements have been ignored.
In this case, though, the anon (in both present and past incarnations) feels that the article's content is incorrect, and is loudly arguing about it. The talk page is the place to discuss article content; the problem is that they seem to be immune to reason, and have in the past disrupted the page to make their point. That said, it's possible that the anon's confusion represents points where the article is not sufficiently clear, so I'd suggest being careful when evaluating whether or not behavior is disruptive.
I'd be happy if they just stuck with current threads and standard talk page ettiquette, myself. --Christopher Thomas (talk) 00:24, 6 November 2010 (UTC)
I agree. I have added an extra explanation to JR's and tried to explain why the article talk page is not the place to discuss this. DVdm (talk) 11:52, 6 November 2010 (UTC)

OK Chris, I'll take a look and see if I can help. David Tombe (talk) 10:47, 6 November 2010 (UTC)

## Centrifugal Force

A couple of years back, there was a prolonged discussion at the centrifugal force page. One of the issues raised was the fact that centrifugal force arises in the context of polar coordinates without involving a rotating frame of reference. For some reason, that viewpoint was strongly resisted. The article as it now stands claims in the lead that there are only two concepts of centrifugal force. I ammended this to five and supplied a source.[2]

The third paragraph from the bottom of the source reads,

Thus Newton uses the term “centrifugal force” in the Principia to describe three very distinct concepts. First, he uses it to refer to a hypothetical repulsive force (such as the force between two electrons), which would result in a hyperbolic path, accelerating away from the source of the “central” repulsive force. Second, he uses the term to refer to the outward force exerted by a revolving object on some framework (such as the force exerted by a roulette marble on the housing). Third, he uses the term to refer to the “fictitious” outward force on a revolving object when viewed from a revolving frame of reference. A fourth context in which the concept of “centrifugal force” may arise is when phenomena are described in terms of curved coordinate systems, such as polar coordinates. Such non-linear coordinate systems are not inertial in the spatial sense, even though they may be static (i.e., not accelerating), as discussed in the note on Curved Coordinate Systems and Fictitious Forces. A fifth usage of the term “centrifugal force” occurs when the inertial forces on an object, relative to a momentarily co-moving inertial frame, are de-composed into tangent and normal components (in the osculating plane). The normal component is called centrifugal force. There is no Coriolis force with this convention, because the particle is always at rest with respect to the co-moving inertial coordinates. Needless to say, all these usages are very closely related, and differ only by context and convention.

The edit was removed by John Blackburne on the grounds that it was confusing, and he questioned where the number 5 appeared in the source. I personally don't find this confusing. Does anybody else here find it confusing? Can we have polar coordinates mentioned in the centrifugal force article as a circumstance in which centrifugal force arises? David Tombe (talk) 17:40, 6 November 2010 (UTC)

If you want to write history of the evolving concept of centrifugal force, the source above is acceptable. Otherwise stick to modern concept, for we are not in 17th century anymore.--Netheril96 (talk) 02:33, 7 November 2010 (UTC)
Netheril96, The fourth context listed above is not history. David Tombe (talk) 10:25, 7 November 2010 (UTC)
Well, I have never seen such an interpretation of centrifugal force before. I personally won't consent to adding that content to Wiki's article unless corroborated by several other sources.--Netheril96 (talk) 11:33, 7 November 2010 (UTC)
David - yes, your changes were confusing, the lead was better as it was previously. The lead made clear that the term was used for your (2) and (3) in Newtonian mechanics, which is as far as your source claims.
Your (1) is not referred to as a centrifugal force in modern physics terminology. It's a repulsive central force. In the same way, gravitation is an attractive central force, and can provide the centripetal force in to keep the earth in its orbit, but in general gravitation is not referred to as a centripetal force. I appreciate that "central, repulsive" can be translated into Latin as "centrifugal", but as your source above says, "it must be remembered that Newton was writing in Latin, using the word centrifugal simply as a literally descriptive adjective signifying the direction away from the center."
Your (4) is already covered in the next sentence in the lead: "The term is also sometimes used in Lagrangian mechanics..." although this could be made clearer by mentioning polar coordinates in the lead (they are already discussed in section 4).
Are the 5 concepts in your lead the same as the 5 concepts listed in your source? Djr32 (talk) 14:01, 7 November 2010 (UTC)

Djr32, I would agree with you about Newton's number (1), and I was not counting it in my count of five. I was making up the five with the Lagrangian which was already mentioned in the lead. As regards number (4), it's interesting that you should equate it to the Lagrangian case. So would I. In fact, my own personal view is that there is only one centrifugal force and that there should only be one article on the topic. This so-called 'reactive centrifugal force' concept is somewhat of a misnomer because it is never a reaction. It is always a pro-active outward force which induces the centripetal force as a reaction. It is in fact a knock-on effect from the one and only inertial centrifugal force.

Anyway, let's get to the point. The existing lead states that there are two concepts of centrifugal force and then it goes on to mention a third concept ie. Lagrangian. Now I am quite happy to merge the Lagrangian and the polar coordinate concepts, but it is important that the readers understand that these concepts do not require a rotating frame of reference. Let me now address the points which Netheril96 has raised. He says that he has never encountered the polar coordinate concept and so he wants an additional source. I will supply two more at the end of this paragraph. He also says further up the page that we don't use a rotating frame of reference in planetary orbital analysis. Correct. We can, but we generally don't. But then when faced with the question which I asked Netheril96 on my talk page as to what is the name of the outward radial force in the planetary orbital equation, he stated that he didn't want to talk about it. That is exactly where the problem lies. There seems to be a school of thought which believes that centrifugal force must be treated within the context of a rotating frame of reference. But it doesn't, and the lead needs to be altered to mention at least three concepts of centrifugal force, because there is clearly a concept in planetary orbital theory which is neither the so-called reactive force nor the fictitious force in a rotating frame of reference.

Here are two more references which an editor supplied to the article in August 2008 but which seem to have disappeared,

"An Introduction to the Coriolis Force" By Henry M. Stommel, Dennis W. Moore, 1989 Columbia University Press. "In this chapter we have faced the fact that there is something of a crisis in intuition that arises from the introduction of the polar coordinate system, even in a non-rotating system or reference frame. When we first use rectilinear coordinates to understand the dynamics of a particle, we commit our minds to the simple expressions x" = F_x, y" = F_y. We think of the accelerations as time rate-of change [per unit mass] of the linear momentum X' and y'. Then we express the same situation in polar coordinates that partly restore the wanted form. In the case of the radial component of the acceleration we move the r(theta')^2 term to the right hand side and call it a "centrifugal force." And "Statistical Mechanics" By Donald Allan McQuarrie, 2000, University Science Books. "Since the force here is radial, it is convenient to use polar coordinates. Taking x = r cos(theta) and y = r sin(theta) [i.e., stationary polar coordinates] then... If we interpret the term [r(theta')^2] as a force, this is the well-known centrifugal force..." David Tombe (talk) 14:52, 7 November 2010 (UTC)

You produced a reference which claimed 5, but now you say that you recognise that only 4 of those should be included, but to get it back up to 5 you double counted one of them. I'm not sure this is the starting point for a productive discussion...
That aside, the thing that you are now complaining is missing (the additional terms that appear when you express Newton's laws in non-Cartesian coordinates) already has a section in the article and is also covered in the third sentence of a lead which is 3 sentences long. No doubt it could be expressed better (e.g. by making the polar coordinates example more explicit), but your edit didn't do this, it just made the lead more confused, and so I agree with John Blackburne that it was better to revert it. Djr32 (talk) 17:53, 7 November 2010 (UTC)

Djr32, There probably would never have been a problem in the first place if it hadn't been for the fact that the idea of centrifugal force in polar coordinates, in the absence of a rotating frame of reference, had met with such strenuous resistance. This latest problem in the lead is the kind of problem which arises when one is forced to word things exactly as per what it says in a source. And for the very same reason, the article lead is still unsatisfactory, because although it mentions three concepts of centrifugal force, it also explicitly states that there are only two. In the past, I wanted to make it three, but since a source specifically said that there were two concepts, then we had to write 'two', and then mention the third one afterwards. And quite frankly, I wouldn't ideally bother mentioning any number in the lead at all. Finally, I'm glad you agree with me that there could be a more explicit treatment of the polar coordinate centrifugal force in the article. Regarding your words No doubt it could be expressed better (e.g. by making the polar coordinates example more explicit), it took nearly four years to get somebody else to admit that. And I apologize that I didn't try and address that issue in the main article yesterday, but if you look at my block record, every single one of those blocks, bar the arbitration ones, was directly or indirectly because I was just trying to do exactly that. So I'll now leave you guys to sort out the centrifugal force article whatever way you please. David Tombe (talk) 19:29, 7 November 2010 (UTC)

Your claims of strenuous resistance are simply not true - the subject you feel is being excluded is discussed in the fourth section and in 1 of the 3 sentences in the lead, and there don't seem to have been any significant changes to either of these over the last year. (I think the "two concepts" sentence is using "Newtonian mechanics" to exclude the use of curvilinear coordinates.) Djr32 (talk) 21:55, 7 November 2010 (UTC)

Djr32, I'm sorry that you weren't around three years ago. I'll repeat below the quote which you made above,

No doubt it could be expressed better (e.g. by making the polar coordinates example more explicit) Djr32

That was my position from the outset. That is the position that resulted in false accusations of 'fringe point of view' and original research and a lengthy block record. I can assure you, contrary to what you say, that that position was strenuously resisted. The Lagrangian section arrived late in the article, around about June 2009, as a consequence of lengthy and productive discussions, and I did consider the Lagrangian section to go about 90% of the way towards settling the issue. But the finalization discussions were rudely halted by an AN/I thread in which two of the editors (myself included) were accused of disruption by a non-physicist. Threats of sanctions prevented any further discussion of the topic.

Just like yourself, I believe that the Lagrangian section could be expressed better by making the polar coordinates example more explicit. But I will not be the one to make the necessary improvement. If you genuinely believe in your statement above and you wish to help wikipedia by expanding the knowledge pool for the benefit of the readers, then you will be the one to do it, because if you do it, it will not be reverted. David Tombe (talk) 00:22, 8 November 2010 (UTC)

## Einstein-Maxwell-Dirac equations?

See Einstein-Maxwell-Dirac equations for a "super-classical theory". Is this a joke or what? JRSpriggs (talk) 14:51, 7 November 2010 (UTC)

## WikiProject cleanup listing

I have created together with Smallman12q a toolserver tool that shows a weekly-updated list of cleanup categories for WikiProjects, that can be used as a replacement for WolterBot and this WikiProject is among those that are already included (because it is a member of Category:WolterBot cleanup listing subscriptions). See the tool's wiki page, this project's listing in one big table or by categories and the index of WikiProjects. Svick (talk) 20:48, 7 November 2010 (UTC)

## The Lorentz Force Equation and Maxwell's Equation (77)

Take a look at equation (77) in Maxwell's 1861 paper On Physical Lines of Force. It can be found on page 342 which is on page 31 of the pdf file. This same equation appears again as equation (D) in the list of eight original Maxwell's equations in his 1864/65 paper [3]. It can be found at page 484 of the original paper on the supplied web link (page 26 of the pdf file). I'd be interested to hear comments on the similarity between this equation and the Lorentz force equation. The Lorentz force equation looks like this,

${\displaystyle \mathbf {F} =q\left(\mathbf {v} \times \mathbf {B} -{\frac {\partial \mathbf {A} }{\partial t}}-\nabla \psi \right)}$

Below equation (D) in the 1864/5 paper, Maxwell writes,

The first term on the right hand side of each equation (he splits it into the three cartesian components x, y, and z) represents the electromotive force arising from the motion of the conductor itself. This electromotive force is perpendicular to the direction of motion and to the lines of magnetic force; - - - - - The second term in each equation indicates the effect of changes in the position or strength of magnets or currents in the field. The third term shows the effect of the electric potential Ψ. David Tombe (talk) 00:17, 23 October 2010 (UTC)

In view of the fact (see Electromagnetic four-potential) that
${\displaystyle \mathbf {E} =-\mathbf {\nabla } \phi -{\frac {\partial \mathbf {A} }{\partial t}}\,}$
this is not at all surprising. The usual expression for Lorentz force is
${\displaystyle \mathbf {F} =q[\mathbf {E} +(\mathbf {v} \times \mathbf {B} )]\,}$
which is equivalent as our article on that mentions. So what is your point or question? JRSpriggs (talk) 07:13, 23 October 2010 (UTC)

JRSpriggs, Thank you very much indeed. That is exactly the answer I was hoping to hear. I was worried that some people might have tried to argue that the equation which I listed above was not the Lorentz force. And if that had happened, I had planned to produce exactly the equation,

${\displaystyle \mathbf {E} =-\mathbf {\nabla } \phi -{\frac {\partial \mathbf {A} }{\partial t}}\,}$

which you have just produced above in order to show them how it relates to the form that they are more familiar with.

OK. The point of my enquiry was to establish that it is perfectly in order for me to go now to the Lorentz force article and to record the fact in the history section that in 1861 Maxwell produced an equation which is mathematically identical to the Lorentz force equation. And that I can do so without being accused of inserting original research. As the Lorentz force article stands right now, Maxwell's involvement with this equation has been totally erased from the history section, and the history section is extremely misleading in that it gives the impression that it wasn't until 1881 that a half baked version of the Lorentz force first arrived on the stage in the hands of JJ Thomson. And as an aside, I don't doubt that JJ Thomson turned up with that half baked version of the Lorentz force, but what I do doubt is that he derived it in relation to any considerations regarding the displacement current. The reason for my doubts is that the dispalcement current is closely connected with that other Maxwell equation known as Ampère's circuital law whereas the Lorentz force is closely connected with the Maxwell equation which was originally referred to as Faraday's law by Oliver Heaviside. David Tombe (talk) 10:55, 23 October 2010 (UTC)

Well, I do see the equations there on page 484. So if we were allowed to use primary sources, then you would be good to go. However, we are supposed to use secondary sources. That is, you need to find a reliable source (someone commenting on Maxwell, rather than Maxwell himself) which says what you and I have both seen for ourselves. JRSpriggs (talk) 11:34, 23 October 2010 (UTC)

JRSpriggs, That of course is exactly the problem. But I think that you may be applying too strict an interpretation of the rule on primary sources. You of course would not be alone in doing so. I once read the rules on primary sources and it was quite clear about the fact, that where the information is unambiguous, there is no problem in using a primary source for verification. I think that this is one such case in which the interpretation is totally unambiguous. It would be a shame to have to mislead readers at the Lorentz force article when we all know that Maxwell came up with this equation in 1861. It would be a shame to hide this information from the readers purely on the basis of an overly strict interpratation of the rules on primary sources. Meanwhile, I have left an enquiry at the 'no original research' noticeboard because I believe that there are editors there who know exactly where to draw the line. All too often I have seen good physics in primary sources being distorted by modern sources often written in the last 15 years. There should be more of a collective effort made to examine the contents of primary sources, especially when the contents are written in plain English. I would have taken 'original research' more to have been something like making further inferences from the material in primary sources, but not to be merely pointing out the obvious existence of an equation or a statement. David Tombe (talk) 12:04, 23 October 2010 (UTC)

Well obviously if you just want to say that Maxwell derived this in 1864/5 and established that this was done before Thomson in 1881, there's no problem. For anything more (i.e. interpretations), you should have solid sources for it. Personally, I'm fine with the original papers for this topic, as long as we keep in mind that they were written in the pre-relativity era (i.e. often written with the aether mindset).
And as a general note, I hope there is no need to remind you that Wikipedia is not the General Science Journal. 12:29, 23 October 2010 (UTC)

Headbomb, Thanks for your response. I'll insert the material into the article while keeping your comments in mind. I'm actually glad that FyzixFighter drew my attention to JJ Thomson's half baked version of the Lorentz force because I didn't previously known about it, and I intend to fully investigate it. But I believe that nevertheless it is important to let the readers know that the full equation in its correct form had been around since Maxwell's 1861 paper. David Tombe (talk) 14:40, 23 October 2010 (UTC)

There is no absolute bar on using primary sources, just that secondary sources are preferred. Logically, of course, the Lorentz force law can't post-date Maxwell's equations, since there is no coefficient between E and B in the Lorentz force. --Michael C. Price talk 15:11, 23 October 2010 (UTC)

Michael, I've got a pdf file with Heaviside's 1889 paper. Is there any way that I can get it into a form that the readers here can read, because it contains some very interesting information. Equation (5) is the v×B aspect of the Lorentz force as applied to charged particles and he comments how this is Maxwell's electromagnetic force equation, and he notes that it is double JJ Thomson's result. It would be good to have a direct link to this paper, because there seems to be no end of confusion regarding these historical subtleties. David Tombe (talk) 15:47, 23 October 2010 (UTC)

Perhaps upload it to Wikisource, or commons? --Michael C. Price talk 16:25, 23 October 2010 (UTC)
Is it one of these two (already at Wikisource)?:
--Michael C. Price talk 04:48, 24 October 2010 (UTC)

Despite this exchange, and despite the fact that it has been agreed that Maxwell's 1861 paper can be used for verification in the circumstances, FyzixFighter as usual has completely desecrated all my corrections at Lorentz force. The history section is now inaccurate and omits any mention of Maxwell's important historical role in this equation. The section now wrongly states that Heaviside invented the Lorentz force.

Now I don't intend to involve myself any further in this matter. FyzixFighter has done this to my physics edits consistently since I began at wikipedia. What he is doing is wrong, but at the end of the day, it is not my personal responsibility to ensure that the electromagnetic history sections are correct. You guys here can see exactly what has been going on. I was lured into a physics topic ban for a year because of this kind of behaviour on the part of FyzixFighter, and so I will leave you guys to sort the matter out whatever way you all see fit. Wikipedia needs to make its mind up as to whether readers should be allowed to read what Oliver Heaviside says, or whether they should be reading what FyzixFighter says that Darigol says that Heaviside says. And who is Darigol anyway? I gave a reference which said verbatim what Heaviside said. Heaviside said that the v×B force is Maxwell's electromagnetic force and that it is double the JJ Thomson result. But FyzixFighter is saying that Darigol says that Heaviside invented the v×B force, and FyzixFighter is ensuring that the readers don't get to know about Maxwell's involvement. Is that the way you all want wikipedia to operate? David Tombe (talk) 19:08, 23 October 2010 (UTC)

Michael, Thanks alot for obtaining that source. The second one of the two is exactly the one that I wanted, and the relevant section is section 5. On the Electromagnetic Effects due to the Motion of Electrification through a Dielectric
Section 5., which is very short, tells the story from the horse's mouth. Heaviside has derived the v×B force on a charged particle, and he acknowledges that it is Maxwell's electromagnetic force. This ties in with the Maxwell sources listed above which tell us that Maxwell produced that force at equation (77) in his 1861 paper. But if you go now to the history section at Lorentz force, you will see that FyzixFighter has erased Maxwell's contribution. FyzixFighter argues that we can't use primary sources. If that were true, then it would mean that we would have to heed what we hear from the likes of Darrigol even though we all know that Darrigol is wrong, since what he says contradicts what we can clearly see written in the primary source. This means that all the history sections in physics articles can be very easily vandalised by anybody who knows how to selectively use secondary sources. And we all know that very few secondary sources ever agree with each other on historical details. So basically, wikipedia has a problem. Having said that, I also understood that sources are not actually needed at all unless somebody doubts the material and demands verification. But in this particular case does FyzixFighter actually doubt the material? David Tombe (talk) 12:55, 24 October 2010 (UTC)
As even basic physics text books (I can give some examples from German text books) contain some observations about this issue, inter alia that the Maxwell equations are invariant with regard to Lorentz transformations, it should be possible to find secondary sources on this.  14:55, 24 October 2010 (UTC)
In fairness to the other side, I should say that: although the mathematical form of the equations on page 484 is correct, someone might doubt whether the variables used in it were given the modern meaning by Maxwell. To decide that would require, at least, a careful study of the whole paper. JRSpriggs (talk) 15:43, 24 October 2010 (UTC)

Cs32en, Thanks for your help. But the issue of Maxwell's equations being invariant with regard to Lorentz transformations is further along in the historical chronology. As a quick summary, the chronology seems to be,

(1) In 1861, Maxwell derives what later became known as 'The Lorentz Force'. It contains three terms on the rhs. One of these terms is v×B. He derives it in relation to the force on electric currents as opposed to the force on charged particles.

(2) In 1881, JJ Thomson derives a half baked version of the v×B force in relation to a charged object.

(3) In 1889, Heaviside derives the Maxwell version for the purpose of applying it to a charged particle, and notes that it is Maxwell's electromagnetic force.

(4) Heaviside, just like Maxwell, drops the v×B term when deriving the EM wave equation.

(5) Heaviside selects a group of 4 equations which are used in the derivation of the EM wave equation/telegraphy equation. This group of 4 of course does not include the v×B term.

(6) Lorentz uses the Heaviside 4, without the v×B term, and he produces the v×B term by subjecting them to a Lorentz transformation. Hence v×B becomes associated with Lorentz.

The major omission in the history section at Lorentz force is the fact that Maxwell's specific role has been eliminated from the chronology, and credit for the v×B term has been falsely ascribed to Heaviside. And Lord Kelvin is largely irrelevant in the context, but has been elevated to a parallel position to Maxwell, hence diluting the importance of Maxwell in the context. David Tombe (talk) 15:58, 24 October 2010 (UTC)

JRSpriggs, Heaviside himself was happy enough that it was the same equation. He said so in section 5 of that web link which is supplied above. What else could the variables mean? I don't get your point. It's a force equation. The terms correspond exactly to the modern form. Maxwell even describes the parallegram of the cross product vividly. We can see the v×B term, the -(partial)dA/dt term, and the grad(phi) term. There is no doubt about this issue. If you leave the history chronology as it stands now, it will be wrong, plain and simple. David Tombe (talk) 16:03, 24 October 2010 (UTC)
Maybe a possible starting point for content based on secondary sources is E. T. Whittaker: A History of the Theories of Aether and Electricity. Relying exclusively on primary source carries the risk of attributing things to Lorentz which have been discovered by Clausius or attributing things to Maxwell which have first been described by Faraday. The term ${\displaystyle v\times B}$ can appear in disguise, of course, as ${\displaystyle B=curl\;A}$ 22:35, 27 October 2010 (UTC)

Cs32en, Just as a point of correction, the term ${\displaystyle v\times B}$ appears in the fourth of Maxwell's original equations, whereas the equation ${\displaystyle B=curl\;A}$ is the second of his original eight equations. The two concepts are not each other in disguise by any stretch of the imagination. The first is about an electromagnetic force acting at right angles to the magnetic field, whereas the second leads to the observation that the magnetic field is solenoidal and leads to the equation div B = 0. David Tombe (talk) 10:24, 28 October 2010 (UTC)

That may be a misunderstanding. I did not want to imply that both equations would mean the same thing. What I wanted to say is that it is possible to express relations that contain ${\displaystyle B}$ in terms of ${\displaystyle A}$ 20:58, 31 October 2010 (UTC)

Cs32en, That's correct. You can indeed. Maxwell believed that ${\displaystyle A}$ was what Faraday referred to as the electrotonic state. By the way, you mentioned virtual particles further down. What is the difference between a particle and a virtual particle? David Tombe (talk) 22:14, 31 October 2010 (UTC)

I'm not an expert in virtual particles, but my guess is that the notion of a virtual particle presupposes the concept of Wave–particle duality, while concepts of the aether do not.  22:46, 31 October 2010 (UTC)

And if we pre-suppose the concept of Wave–particle duality, how does a virtual particle differ from a particle? David Tombe (talk) 22:54, 31 October 2010 (UTC)

As I've said, I'm not an expert in these things, so it's probably best to consult an advanced physics textbook. Don't rely on Wikipedia for that kind of information ;-) The (brief) presentation of Maxwell's contribution in Wave–particle duality may need to be stated in more precise terms, btw.  23:06, 31 October 2010 (UTC)

Yep, I had a look. It seems that they have mixed up Maxwell's original works with Heaviside's four 'Maxwell's equations' that are used in modern textbooks to derive the EM wave equation. Somebody has obviously learned EM theory from a textbook and then presumed to write what is in their textbook, into the history, as if that this is exactly how Maxwell did it. David Tombe (talk) 23:15, 31 October 2010 (UTC)

It's a good example that shows why things that may seem obvious or trivial should be cited to reliable sources. Then we would at least know where the faulty information originated from.  23:46, 31 October 2010 (UTC)

A secondary source has now been found [4]. Problem solved. David Tombe (talk) 09:44, 9 November 2010 (UTC)

## Golden age of general relativity

There seems to be a systematic removal of mentions of the "golden age of general relativity" underway, most recently by Steve Quinn (talk · contribs). I don't recall seeing any discussion of this, and I'm pretty sure I've seen the term used outside of Wikipedia. A quick check of Google Scholar finds a few mentions (the earliest I've seen being an academic paper from 1982), and vanilla Google for the term (with "-wikipedia" to filter out wiki mirrors) finds many general mentions (albeit with several either derived from wiki text or using the same reference the wiki text was derived from).

Does anyone have their copy of MTW or more recent texts handy to see if the term has been used in teaching materials? I'm not sure where my copy of MTW went, and it may predate use of the term (not sure what edition it is). --Christopher Thomas (talk) 07:06, 2 November 2010 (UTC)

As far as I know, the term "Golden age" when referring to the rapid development in general relativity in the 60s and 70s is quite common. MTW will be of little help since it was published at the end of what is now considered the golden age. (The fact that it is still THE text on the subject tells us how remarkable the development in that period was.) Some googling suggests that the use of the term may have originated with Kip Thorne in Black holes and time warps: Einstein's outrageous legacy. I suggest that these edits be reversed.TimothyRias (talk) 07:49, 2 November 2010 (UTC)
Speaking of MTW, a sentence in Sign_convention#Metric_signature reads "Regarding the choice of − + + + versus + − − −, a survey of some classic textbooks reveals that Misner, Thorne and Wheeler chose − + + + while Weinberg chose + + + − (with the understanding that the last sign corresponds to "time")." which seems like either a mistake, or something in need of clarification (if they are not arguing about wheter to user +--- or -+++, but rather the order of coordinates). 08:01, 2 November 2010 (UTC)
It is a mistake, as it says 'with the understanding that the last sign corresponds to "time"'. A. di M. (talk) 11:07, 2 November 2010 (UTC)
Here's an article that uses the term: [5] --Steve (talk) 08:06, 2 November 2010 (UTC)

Surely today's age is as golden as any. According to MATHEMATICAL GENERAL RELATIVITY: A SAMPLER: "There has recently been spectacular progress in the field on many fronts, including the Cauchy problem, stability, cosmic censorship, construction of initial data, and asymptotic behaviour". 89.241.239.125 (talk) 13:22, 3 November 2010 (UTC)

Sorry to jump in so late here. I haven't been on Wikipedia much lately - taking a break. I was unable to find anything on the Golden Age of General relativity. It appears to me to be a made-up term. And even more so any reference to the this "golden age" occuring during the 60's and 70's does not seem to exist. If anything I would think that we are still in the golden age of relativity if there were such a thing - as far as I can determine there is not one. The article for which this was the title was a point of view essay type thing. I merged the content, after making some changes, to the History of General Relativity. The "Golden age of relativity" is now a redirect. I thought there was some discussion about this when I discussed some content forks and merging one article into another, earlier in this thread. In any case I think this needs to be removed from articles given the lack of sources. ---- Steve Quinn (talk) 06:28, 6 November 2010 (UTC)
Also, the redirect probably needs to be deleted. I really thought I was clear about this. Also, in the PROD tag I wrote: "There is no such thing as the "Golden age of relativity", this is a made up term see: WP:MADEUP."
I also made a similar comment in the edit history earlier. When I come across original reasearch I am not required to discuss removing it here, as far as I know. In any case, I did bring it up earlier, in the same thread (section) as the content forks. I have to admit this thing about the "Golden age of general relativity" has become a bit frustrating. I have discussed deleting this redirect with two admins prior to my PROD, and all I got was ignored by one, and another who didn't seem to understand. Now, an editor declined my PROD a few days ago. I know this project does not find made up, POV, commentary acceptable. But, this issue has been a tough one to deal with for some reason. ---- Steve Quinn (talk) 07:06, 6 November 2010 (UTC) 07:04, 6 November 2010 (UTC)
The reason you added the tag was very clear; I simply think that you are mistaken about the term not being used, and it seems that I am not the only one who feels that way. The Kip Thorne book alone is sufficient for demonstrating use and notability, assuming we can get a proper page citation for it (that book was famous, and so is Thorne). --Christopher Thomas (talk) 07:10, 6 November 2010 (UTC)
The only reference I came across which uses this term, was published in July 2007, on page 8:
Walecka, John Dirk (July 2007). Introduction to general relativity (342pp). World Scientific Publishing Company. ISBN 9789812705846.
It says: "Ours might be called the golden age of general relativity. Satelite observations continue to push the boundaries of our understanding".
This single source indicates that we might be in a golden age of general relativity at this time. My intution says the same thing. But my intution is not verifiable. And this source is not actually making any kind of claim. So, with all due respect, all I am seeing is general assumptions by other editors, that use of this term must be accurate. It appears to me, after conducting various searches, that there are no sources, which say that any period of time is really the "golden age of general relativity". It does not appear to have widespread usage. Therefore, it is a made-up, POV, term and so is any content that could be written about it. Hence, I am going to put this up for RfD (redirects for discussion). ---- Steve Quinn (talk) 01:10, 7 November 2010 (UTC)
If you found only a single source, then frankly, you haven't looked. Did you miss the 1982 article that was the first hit on Google Scholar for the term, as one example? Please take care to perform due diligence before a) unilaterally deleting these terms from Wikipedia articles, and b) claiming that they're WP:MADEUP. --Christopher Thomas (talk) 08:13, 7 November 2010 (UTC)
Here is another source which implies to me that a "golden age" of general relativity is not clearly defined, might be related to different time period, and is still not in widespread use [6]. ---- Steve Quinn (talk) 01:10, 7 November 2010 (UTC)
The link just above is the first hit on Google Scholar. Therefore, I did care to perform due dilegence. Also, I am not "unilarterly" deleting these terms from Wikipedia - I don't have that kind of power, nor do I have tools to carry out such a thing. And, yes, the more I search the more I see that this term is WP:MADEUP. There is a dearth of sources that use this term. Of the very few that do use it, there is no defined Golden age of General Relativity. I think that you need to perform due dilegence before making such claims, regarding me, and sources in this matter. Also, there is a whole set of books on Google Books that have copied the unsoruced OR article that used this term, and put it in print. I would appreciate it if you would not make it seem that there are more clear sources available regarding this term, than there really are. One source on Google Scholar demonstrates nothing. Did you see the other sources listed on that page, and the following page. There is nothing on this. The one google scholar source is ambiguous at best, and does not support golden age between '60's and 70's. ---- Steve Quinn (talk) 04:17, 8 November 2010 (UTC)
Also, yes, I did remove this term from some pages, because I assessed this term as unsourced POV and OR, after reviewing the article, checking the sources, and doing some searches (before the merge). Removeing the this term from articles, after assessing it as nothing more than someone's made-up term, for some made-up time period, appears to be appropriate to me. Also, I thought this was understood from my first entry some time ago. So, to say that I unilaterely made some sort of decision is not accurate. And this is what happens to unsourced OR anyway. So I don't get the contradiction in attitude here. ---- Steve Quinn (talk) 05:22, 8 November 2010 (UTC)
It does not seem appropriate to me. Discuss on the article talk pages, at minimum, before doing a wholesale merge plus scrubbing of links to the term. Preferably, ask people here if they've heard of the term too, as last I checked there were at least a couple of lurkers whose field of study is relativity. As far as I can tell, the article was merged by you with little to no discussion, and all references to the term were removed by you, not by other editors. Bold changes like this are sometimes appropriate, but very often not. That's why discussion is encouraged first.
Have you even checked Kip Thorne's book, as Timothy suggested? Searching for "+"Kip Thorne" +"golden age" -wikipedia" comes up with quite a few references to his popularization of the term (variously quoted as "golden age of relativity research" and "golden age of black hole research" for most of these secondary references).
I don't doubt your good intentions. However, you seem to be running the "investigate/discuss/change" cycle exactly backwards. --Christopher Thomas (talk) 05:42, 8 November 2010 (UTC)
• Unfortunately, the Kip Thorne references are about "Golden Age of black hole theory." (one says 1964 to 1974). This is basically what I have been talking about. The search term "goldan age of general relativity" leads to other references, nostly not that phrase. Here are some reviews for Kip Thorne's book, and it can be seen these refer to "Golden age of black holes" or... black hole theory - [7], [8], [9],. Here is some sort of encyclopedia article pertaining to General relativity. [10]. This is just bibliographic and summary information [11]. And there is still the other reference on the Project talk page which alludes to the fact that we may currently be in a golden age of general relativity. Next, might be called "History of mathematical general relativity" in the introduction [12]. ---- Steve Quinn (talk) 07:01, 8 November 2010 (UTC)
• (Inserting high, rather than low, so context is visible.) ...Please re-read my response. Kip Thorn is referenced as referring to both a "golden age of black hole research" and a "golden age of relativity research". If you run the search I described, or click on the link I provided for it at the RfD, this will be immediately apparent. Search without "general" to find more of these. It is causing me concern that I'm having to point this out, as it indicates that you either did not run any such search or did not examine the results in detail. --Christopher Thomas (talk) 23:32, 8 November 2010 (UTC)
• Christopher, at least all of us( Timothy Rias, you, and I) agree that Kipp Thorn discusses a "golden age of black hole resarch". Now moving to the next phase of our development:
I am basing the following search on your link, looking for "golden age of relativity research" and you may be happy with the results:
1. The first hit "Catching waves with Kip Thorne" : "The gravitational wave detectors being built by Thorne's colleagues will provide the first opportunity to test theoretical predictions made during the "Golden Age" of black hole theory, 1964 to 1974", and "It was then that the theoretical study of black holes was accelerated into what Thorne calls the "Golden Age".
2. The second hit, is the same document as the first, but longer and yeilds the same results.
3. Third hit "The future of theoretical physics and cosmology: celebrating..." using your search term results in Golden age of black hole research, or black hole theory. Using the search term "golden age of relativity" yeilds the same results, except there are references to "classical general relativity". This term is probably worth investigating.
4. Fourth hit - this is a Caltech site and it actually uses "The Golden Age of General Relativity" as a title for this page [13]. There is also a reference to "a golden age of relativity research" - very interesting. I admit that I overlooked this during my last search. This is definitely a relevant piece of information. Also the time period is a little different "1965 into the 1980s", but that is not a problem. I reccomend combining this, with content related to "classical general relativity" for an article. As it stands I may have to take a giant step backwards, with egg on my face. OK I am going to do a change up on search terms here.---- Steve Quinn (talk) 06:03, 9 November 2010 (UTC)
Here are some search results for "Golden age of relativity" (from your comment in the edit history): These use the term [14], [15], [16], [17]. This last link also mentions John Wheeler, Charles Misner, and Kip Thorne.
I have come across this next link at least several times, and it appears to be a mix of information not related to the title is purports to be about, "Golden age of general relativity" - it makes no sense [18]. ---- Steve Quinn (talk) 07:08, 9 November 2010 (UTC)
• Even though I don't see a consensus here for doing so - I will see if I can undo the merge, so that you and others may inspect the article for yourselves. In fact I should probably defer the delete discussion until I get some sort of thumbs up. I suppose it is possible to defer the delete discussion? ---- Steve Quinn (talk) 07:23, 8 November 2010 (UTC)
• I am not going to attempt to undo the merge. The article was POV and and unsourced OR, and the appropriate action was to merge the salvagable contents. Perhaps, I should have been clearer regarding my actions, and in the future I intend to do so. However, now that it is done I cannot support re-creating an unsourced OR or POV article. As I stated below, this inaccurate information has already found its way into print, because of this article. ---- Steve Quinn (talk) 19:29, 8 November 2010 (UTC)
• Pre-merge article - Coincidentally, there is another redirect with this same title except for Captial letters (as for proper nouns). Here is the article just before I merged it. I didn't undo the merge, I just copy and pasted this version onto the redirect with capitals. I removed the redirect for the time being. [19]. ---- Steve Quinn (talk) 07:47, 8 November 2010 (UTC)
• This is what I wrote in the section above entitled Possible content forks: "Also, you might be interested that I just merged content into History of general relativity from an article which consisted of someone's POV commentary, and a timeline. You can read about in the edit histories. I had to request speedy delete for the resulting redirect because it appears to be synthesis of some sort. I might need to leave a comment on the History of GR's talk page. "
OK, I failed to leave a comment on the History of general relativity talk page. I did intend to. I don't know what happened, except I forgot to do this. ---- Steve Quinn (talk) 08:03, 8 November 2010 (UTC)
• So, in the future I will make sure to discuss after investigating, and before I make any changes - such as clearly indicating that I wish to merge, or that I wish to remove content from several articles (which isn't vandalism). And I will wait for responses before merging, and agreement on the appearance of WP:OR. I pretty much did this in the past except (apparently) in this instance. (investigate/discuss/change) ---- Steve Quinn (talk) 08:27, 8 November 2010 (UTC)
By making your various contoversial moves and copy and paste mergers, you have all but destroyed the article history. I suggest that the situation be restored to the situation as it existed prior to your unilateral action. (This means that that History of GR needs to be moved back to Golden age of general relativity, for which the current redirect at Golden age of general relativity needs to be deleted (and thus needs an admin to do it)) We can then discuss what to do with the situation.
It is clear that there was period in the 1960s and 1970s in which exceptional progress was made in GR in particular in relation to black holes. This period is clear identified as special by various authors but known under slight different names: "Golden age of general relativity", "Golden age of black hole research" or simply as "the golden age". Some use of these terms is documented by Brandon Carter in [20], who alse describes what is special about that period and would serve as an excellent source to improve the article when it is restored. But whatever it is named this period in the developement is clearly notable enough to deserve it own article.TimothyRias (talk) 09:40, 8 November 2010 (UTC)

Just some more sources mentioning this "non-existant" golden age:

Also, I don't have a problem with keeping the redirect, since it appears to already get 1000 hits per month. As Boing! points out a redirect does not have to be notable. It is just a way for people to arrive at their target article. ---- Steve Quinn (talk) 19:00, 8 November 2010 (UTC)
So, I really don't want to see that content merged back under the title "Golden age of general relativity". I think the better course of action is rename the redirect entitled "History of GR", (to "Golden age of black hole something or other") since this already contains the article history. I think "Golden age of general relativity" would have to be renamed anyway, and this saves a step. I still think merging the salvagable contents of that article into History of general relativity was the appropriate course of action, simply because it was POV and unsourced OR. ---- Steve Quinn (talk) 19:11, 8 November 2010 (UTC)
I struck one of my comments above. This is because, I am not going to attempt to undo the merge. I think it is best to just move forward and use the History of GR redirect to make a new article.---- Steve Quinn (talk) 19:45, 8 November 2010 (UTC)
Based on searches with positive results (see above) I am going to seek out an Admin so that the situation be restored to the situation as it existed prior to my action. (This means that that History of GR needs to be moved back to Golden age of general relativity, for which the current redirect at Golden age of general relativity needs to be deleted. Also, the previously merged material can be merged back. And as Timothy Rias stated above, we can then discuss what to do with the situation. ---- Steve Quinn (talk) 07:23, 9 November 2010 (UTC)
• In order to, hopefully, fix this problem I have requested Administrator assistance here. -------- Steve Quinn (talk) 08:00, 9 November 2010 (UTC)
• I apologize for creating this mess, and causing extra work for other people. ---- Steve Quinn (talk) 08:25, 9 November 2010 (UTC)
The article has been restored to its premerger state. It has many issues, but I suggest we continue any discussion of how to deal with them on the talk:Golden age of general relativity.TimothyRias (talk) 09:07, 9 November 2010 (UTC)

### RfD

For interested persons:

---- Steve Quinn (talk) 03:24, 7 November 2010 (UTC)

### Merge proposal

I've added proposed-merge templates to the GAoGR and HoGR, with more detailed comments at Talk:Golden age of general relativity#Proposed merge with History of general relativity. I've also sent email to the original author of GAoGR (User:Hillman) asking for pointers towards the references he used, but the email address I have on file looks like it went stale a couple of years ago.

Long story short, User:Steve Quinn has convinced me that the references aren't strong enough to have an entire article on the subject (though I support preserving its contents). I invite anyone who can spare a few moments to comment at the talk page thread. --Christopher Thomas (talk) 23:20, 9 November 2010 (UTC)

Good catch with adding merge templates to Golden Age of General Relativity (capitalized title). However, a manual diff showed that all content from that version was already present in the new version. I've stuck a speedy-deletion tag on the capitalized page, as it doesn't seem to have an edit history that needs preserving either (it was created after the original was moved, has two or three minor tweaks as a redirect, then had a cut-and-paste copy of the original content added). --Christopher Thomas (talk) 22:53, 10 November 2010 (UTC)

## AfD

For interested persons:

---- Steve Quinn (talk) 03:24, 7 November 2010 (UTC)

I think I can do a workable re-write of this article to match some sources. It appears "Golden age of physics" can fit different time periods, and stating that in the form of an article may be the best approach. ---- Steve Quinn (talk) 05:49, 11 November 2010 (UTC)

## Is the age of the universe relative?

I asked this question at the reference desk, but got two contradictory responses... Please, what is the definitive answer? Thanksverymuch (talk) 03:10, 8 November 2010 (UTC)

As BenRG (talk · contribs) said at Wikipedia:Reference desk/Science#Is the age of the universe relative?, "the usual quoted age of the universe is the maximum elapsed time from the big bang" along any path from the Big Bang to here and now. If you want more explanation, then please tell us what you mean by "relative". JRSpriggs (talk) 07:11, 8 November 2010 (UTC)
Please see the response by Red Act. Thanksverymuch (talk) 12:35, 8 November 2010 (UTC)
By my reading, Red Act said almost exactly the same thing as BenRG. However, if you think their responses are contradictory, you should ask for clarification back at the Science Ref Desk, so that the discussion stays in one place. Gandalf61 (talk) 12:53, 8 November 2010 (UTC)

## Templates for specific books

Lately I have been quite irritated by typing out the same thing over and over for references. I have a tendency of using the same books quite a lot for references and I am lazy. (By lazy I mean I am willing to spend hours of time finding ways to do 5 minutes of boring work.) I know about the cite templates which help, but I am always forgetting something and I still have to look up the ISBN number, etc. I suppose I could make a specific cite Jackson template designed for subst, but I am worried about plugging up the template space. Any thoughts. How do others get around this. I am trying to do the right thing with references. Any help simplifying the process before I go batty (oops too late) would help. Thanks. TStein (talk) 23:23, 9 November 2010 (UTC)

I've just run a quick test, and confirmed my vague memories that curly-braces will transclude from anywhere, not just template-space. If you set up sub-pages in your userspace, {{subst:User:TStein/AReferenceName}} should do the job. --Christopher Thomas (talk) 23:29, 9 November 2010 (UTC)
Most of the time DOI bot, activated for a certain page, finds the correct ISBN numbers. -- Crowsnest (talk) 23:33, 9 November 2010 (UTC)\
Maybe you could try Zotero if you are using Firefox. It is an open source add-on to organize references and the most important, able to export in Wikipedia citation template form.--Netheril96 (talk) 03:06, 10 November 2010 (UTC)
To TStein: You could keep copies of all your standard citations on a subpage of your user page and then just cut and paste them when you need to put one into an article. JRSpriggs (talk) 10:06, 10 November 2010 (UTC)

Thanks for all of the suggestions. I will give them a try soon.TStein (talk) 18:01, 10 November 2010 (UTC)

## In the Template:Particles, should Superatom be listed there?

In the Template:Particles, should Superatom be listed there? —Preceding unsigned comment added by Marasama (talkcontribs) 18:42, 11 November 2010

I'd say "yes", given that various other atoms and atom-like composites are also listed, but I'd be equally happy to see all of those moved off to a "condensed matter" template. --Christopher Thomas (talk) 19:41, 11 November 2010 (UTC)
What Thomas said. A. di M. (talk) 01:41, 12 November 2010 (UTC)

## Book:Landmark experiments in physics

I recently created this book about landmarks/famous experiments of physics. I'd appreciate it if you could give it a look, see if I missed anything, or if some of these should be left out. Thanks. 01:17, 12 November 2010 (UTC)

• Since I am helping and editing articles in the field of general relativity at the moment, I may be able to suggest some theoretical landmarks, and maybe some experiments in this area. What about landmarks or experiments in Tests of general relativity? Also, I am trying to find a good article for experiments pertaining to Gravitational time dilation. Hope this helps. --- Steve Quinn (talk) 07:53, 12 November 2010 (UTC)
I notice that your book links to Two-body problem in general relativity. Since that is a theoretical problem rather than an experiment, I have to ask why? If there is an experiment mentioned in that article which you consider to be a landmark, does it not have its own article? JRSpriggs (talk) 09:00, 12 November 2010 (UTC)
Ah I didn't notice that... I wanted Perihelion precession of Mercury, which redirects to the two-body problem in GR. It really should be its own article. 16:39, 12 November 2010 (UTC)

Headbomb, What about the experiment in 1856 by Wilhelm Eduard Weber and Rudolf Kohlrausch in which they established the link between the speed of light and the electromagnetic constants? It involved discharging a Leyden jar. That is a landmark experiment in the history of electromagnetism. David Tombe (talk) 16:45, 12 November 2010 (UTC)

There's no article on it. You can't include what doesn't exist. 17:12, 12 November 2010 (UTC)

I see. It's a book with links to already existing wikipedia articles. Just while we're on the subject, I wonder does anybody here have a link to the original 1856 Weber/Kohlrausch paper. David Tombe (talk) 19:43, 12 November 2010 (UTC)

## Magnetic_accelerator_gun

FYI Magnetic_accelerator_gun has been prodded for deletion. 76.66.203.138 (talk) 06:36, 12 November 2010 (UTC)

## Fearture article review of Herbig-Haro object

I have nominated Herbig-Haro object for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Delist" the article's featured status. The instructions for the review process are here. Tom B (talk) 22:50, 14 November 2010 (UTC)

## Dark matter

Please see the last few edits to . There is disagreement over whether a recent addition is appropriate. --Christopher Thomas (talk) 23:58, 14 November 2010 (UTC)

Not without a proper source (one which would also explain what the hell such a curvature of space would be caused by). A. di M. (talk) 00:42, 15 November 2010 (UTC)
The editor inserting the material now seems to be active on the talk page, so by all means quiz them about it. --Christopher Thomas (talk) 01:12, 15 November 2010 (UTC)

## Astronomy 533 at University of Michigan

FYI, at WT:WikiProject Astronomy, there is a notice that this class will be editing several astronomy articles (which covers astrophysics as well). 76.66.203.138 (talk) 07:14, 19 November 2010 (UTC)

## Quantum field theories template

Hi all, currently the link to Minimal model in {{Quantum field theories}} is a disambig. Any suggestions on how to fix it? I was considering replacing Minimal model with Conformal field theory. Also, shouldn't redlink Lower dimensional quantum field theory go? Thanks, --JaGatalk 03:23, 20 November 2010 (UTC)

Took care of it. --JaGatalk 22:50, 22 November 2010 (UTC)

## Gyrovector space

Hi, an IP has posted at the conflict of interest noticeboard here saying that they think the gyrovector space article is a piece of self-promotion by Abraham Albert Ungar. I can't really see it, at least not obviously, but if someone who knows something about it could check to see if it is neutral and not giving undue weight to his publications it would be appreciated. Thanks SmartSE (talk) 20:27, 21 November 2010 (UTC)

## Wikipedia:Scientific citation guidelines

(Just a courtesy note.) There has been some discussion recently about whether Wikipedia:Scientific citation guidelines needs to be updated to reflect current practice. This wikiproject is one of the projects that had signed on to this guideline in the past. If you have any comments or concerns about the guideline, please feel free to comment at Wikipedia talk:Scientific citation guidelines. If this project no longer wants to be named on the guideline page, you may remove yourself from the list at the top of the guideline page. — Carl (CBM · talk) 18:54, 22 November 2010 (UTC)

## Standard-Model Extension and related articles

There are a whole bunch of effectively orphaned articles on this topic that were added earlier this year: Standard-Model Extension, Bumblebee models, Lorentz-violating neutrino oscillations, Antimatter tests of Lorentz violation. They only seem to have links between themselves, and aren't linked to any of the wider articles on the topic, e.g. Standard Model, Beyond the Standard Model, etc. I don't have the background to do much here, but perhaps someone who knows this area a bit better than I do could add some links to put the articles in context? Djr32 (talk) 12:28, 21 November 2010 (UTC)

They have been brought up before here. As I said then: These articles set of all sorts of alarm bells, for example, each of them has been created by a single-purpose account around the same time. Moreover, the subjects are a bit fringy. However, on the surface there does not seem to be much wrong with the articles themselves. The subjects seem to pass WP:N and the articles are pretty well referenced (although mostly with primary sources, which is a reason for concern). Most likely the articles suffer from WP:UNDUE issues.
I'm not entirely sure how to deal with these articles.TimothyRias (talk) 09:18, 22 November 2010 (UTC)
See the link above for the old discussions on the topic. Perhaps we should consider merging them all with Beyond the Standard Model. 23:09, 22 November 2010 (UTC)
I don't think merging into beyond the Standard Model is a good idea. "Beyond the Standard Model" is a very broad topic, any extensive discussion of these ideas in that article would lead to WP:UNDUE issues.TimothyRias (talk) 06:45, 23 November 2010 (UTC)
Outside the standard model would be a better title. Xxanthippe (talk) 07:16, 23 November 2010 (UTC).
Oops, yes, I had forgotten that these had been mentioned before. However, I think that this is separate to my point - given that these articles do exist (and have been around for several months) then it's undesirable to leave them as a completely walled garden - if they were linked from articles which provided a wider context, they are more likely to be fixed / improved / merged / deleted (pick as appropriate). Perhaps the simplest thing to do is just to put them as see also's in Beyond the Standard Model. Djr32 (talk) 20:34, 23 November 2010 (UTC)
If you want to link them from some where, then Lorentz covariance#Lorentz violation would be the natural place to do so, I think.TimothyRias (talk) 10:59, 26 November 2010 (UTC)

## New category: Metric tensors?

Headbomb (talk · contribs) has created a new category, Category:Metric tensors, and is populating it with articles such as Kerr metric. It is not clear to me why we need such a category at all. But if we are going to have one, I think it would be better for him to just make Category:Exact solutions in general relativity a subcategory of it rather than adding each of those articles individually. JRSpriggs (talk) 12:57, 26 November 2010 (UTC)

Moving on, I intended this category to contain metrics in general (so the name Category:Metrics would be better, but it's taken so I went with Category:Metric tensors, although perhaps Category:Metrics (mathematics) would be the best choice for what I meant in the long run), not only those of General Relativity. I just had the time to hunt down the GR-metrics last night, I'll add the others over the course of the day/weekend. 17:27, 26 November 2010 (UTC)
Hyperbolic & spherical geometries: Do you intend to include the various models listed at hyperbolic geometry#Models of the hyperbolic plane and similar models of (hyper)spheres? And Minkowski metric. JRSpriggs (talk) 13:04, 27 November 2010 (UTC)
A book that could be useful here: Encyclopedia of Distances, By Michel M. Deza, Elena Deza 2.97.29.182 (talk) 14:07, 27 November 2010 (UTC)
Also consider Euclidean geometry, and Nambu–Goto action which is based on a metric on the two dimensional world sheet of the super-strings. JRSpriggs (talk) 15:06, 28 November 2010 (UTC)

## Article proposal: Roger Penrose's Conformal Cyclic Cosmology

I'd like to propose an article about the Conformal Cyclic Cosmology recently postulated by Roger Penrose. I stumbled across it in this article on bbc.co.uk but couldn't find any more than a few articles here mentioning it, without elaborating. (Here's some more information: arxiv.org) It looks sufficiently relevant to warrant its own article, IMO. I'd do it myself, but beside a tremendous curiosity, I don't know enough about cosmology in order to even write a convincing stub about it... -- megA (talk) 17:07, 27 November 2010 (UTC)

Don't let that stop you. It doesn't stop anyone else. Haven't you read WP:How to write stubs without really knowing anything about anything. 2.97.27.161 (talk) 22:31, 27 November 2010 (UTC)
I'd have to do quite a lot of archive-digging to find it, but this looks a lot like a reference to a paper that already came up either here or at Talk:Big Bang or similar, that attempted to construct a situation where a universe at low-density heat death can be considered mathematically equivalent to a universe with a high-density primordial plasma. The problem is that this requires there to be no absolute references for energy scale, and we do have such references (the Planck energy, the masses of the various particles, etc).
With regards to notability, this is a popular press article about a preprint (not even a published paper, much less a group of such papers). I'd hold off on writing an article about it until more academic papers about the idea are found. --Christopher Thomas (talk) 23:32, 27 November 2010 (UTC)

## FLRC

I have nominated Timeline of discovery of Solar System planets and their moons for featured list removal here. Please join the discussion on whether this article meets the featured list criteria. Articles are typically reviewed for two weeks; editors may declare to "Keep" or "Delist" the article's featured status. The instructions for the review process are here. The Rambling Man (talk) 13:56, 28 November 2010 (UTC)

## WPAstronomy

FYI, at WT:WPSPACE there is a proposal to abolish WPAstronomy, while at WT:Astronomy there is a suggestion to remove Astronomy from WPSpace heirarchy entirely. These proposals may be of interest to you, because of the joint coverage of Astrophysics articles between WPAstronomy and WPPhysics. 76.66.194.212 (talk) 08:14, 22 November 2010 (UTC)

This has expanded into a full WP:RFC ... see Wikipedia talk:WikiProject Space/2010 Reorganisation . -- 76.66.202.72 (talk) 02:42, 30 November 2010 (UTC)

## Cepheid variable

FYI, Cepheid variable has been suggested to be renamed and rescoped. 76.66.194.212 (talk) 06:13, 23 November 2010 (UTC)

• Anonymous IP 99.192.66.42 has rewritten parts of this article. Cephid variable has been changed to "Classical cephids" in the introduction, and throughout the article (see edit history) - along with supporting content. Then this anonymous IP has placed a requested move tag on the talk page. The move is proposed to be from Cepheid variable to Classical Cepheid variables. I have objected to the move because the rationale is misleading. First, they rewrote the article to suit themselves. Then they requested a move in such a manner, as if the content of the article were about Classic Cephid variables all along. This looks like some form of POV pushing. It also appears that some of the references have been changed to support this person's content, but I can't be absolutely sure about that. Someone familiar with this article could probably make that determination better than I. If the anonymous IP wishes to have an article on "Classical cephids" then the anonymous IP is encouraged to write one. I am inclined to undo this person's changes, mainly because of the alterations in the introduction from Cephid variables in general, to only Classical Cephids. The changes, and requested move don't make sense to me other than POV pushing. ---- Steve Quinn (talk) 06:18, 26 November 2010 (UTC)
Cepheid variable was rewritten again, this time by 142.177.21.25 (talk · contribs) ; making the article about classical cepheids. 76.66.202.72 (talk) 03:19, 30 November 2010 (UTC)

## Vacuum airship

I have tagged Vacuum airship with {{Expert}} requesting help from Wikipedia:WikiProject Physics with this reason: "after checking some of the citations I am doubtful they are useful sources; some appear to be just the blind leading the blind and vague hand-waving; also this article needs specific cites and not original research". The latest addition of an unsourced table of calculations prompted me to do this. I also added (yet more) {{Citation needed}} tags and noted a possible contradiction with what Pressure vessel#Scaling claims. I have watched this article for over one year but have never seen a scientifically reasoned justification for the claims made. I am hoping a physics expert can help here. -84user (talk) 20:57, 28 November 2010 (UTC)

These show up quite a lot in science fiction, but I can't point to any serious proposals for them. I'd run numbers myself a while back and concluded that they could be built with carbon-fiber composites, so I wouldn't say they're out of reach of present materials (as the article claims). That said, without proper engineering-related sources discussing vacuum balloons/vacuum bubbles, I'd suggest rewriting this to describe it as a fictional technology. --Christopher Thomas (talk) 21:36, 29 November 2010 (UTC)

I removed the table and its description since none of it made any sense from the perspective of a pressure vessel. I moved it to the talk page in case I missed something of merit. I agree with Christopher Thomas that I can't imagine these being useful. The extra material needed for the 100 fold increase of pressure and to prevent buckling is significant even for the strongest of materials. (Air ships typically have gauge pressures that are only a few percent of atmospheric pressure.) TStein (talk) 22:13, 29 November 2010 (UTC)

This source might be useful: [22]. Also this [23]. Arthur De Bausset and the Transcontinental Aerial Navigation Company of Chicago is an interesting story. --Kkmurray (talk) 22:30, 29 November 2010 (UTC)

## Macrocarpum laws of astronomy

FYI, Macrocarpum laws of astronomy has been prodded for deletion... (though it might qualify for speedy deletion... I can't read Russian, and the source paper is in Russian) 76.66.194.128 (talk) 08:40, 29 November 2010 (UTC)

## Nucleosynthesis

In nucleosynthesis, is there a Y-process? Was reading it on this [24], though not sure about since I think it is part of a supernova process? Y-process does not exist in Wiki. Thanks, Marasama (talk) 16:04, 29 November 2010 (UTC)

The Google hits I can find for "Y process" all seem to be describing photodisintegration, so I'd suggest redirecting "Y process" to there. The paper link you give does not use the term "Y process", and also does not appear to be describing photodisintegration, so I'm puzzled as to what you want people to look at in it. --Christopher Thomas (talk) 21:32, 29 November 2010 (UTC)
Used google cache to not view it in Adobe. Appearently it made an error. However I've seen it on other papers, but after searching some more, it appears to be a "gamma", not a letter "y". Based on this paper, [25]. Also appears in the reference paper on Supernova page, [26]. Sorry for the confusion. But "γ-process" does not pull any hits on wiki, and not sure where it would fit to or at least mentioned if it is not a significant process. Thanks, Marasama (talk) 22:42, 29 November 2010 (UTC)
Your first link explicitly mentions the p-process, and discusses photodisintegration. The second paper appears to be describing photodisintegration as well, so I'd say that this is already adequately covered in Wikipedia. If you want to create redirects pointing to photodisintegration, go ahead. I'm just not sure they're widely used enough as search terms for that to be worth the trouble. --Christopher Thomas (talk) 00:40, 30 November 2010 (UTC)