# Wikipedia talk:WikiProject Physics/Archive 8

Archive 7 | Archive 8 | Archive 9

## Event horizon rewrite

The event horizon article was recently rewritten. An anon has voiced concerns about it. Just to make sure it's correct, could a few of the GR-types here please take a look at it, and comment on the talk page? --Christopher Thomas 17:26, 3 July 2006 (UTC)

The anon is still present and still making objections. My math isn't good enough to tell for certain whether or not he has a point (though I'm pretty sure he's mistaken, and the article did get a vote of confidence from the other editors reviewing it). I know there are GR types here. Could a couple of you please take a quick look at event horizon and talk:event horizon? --Christopher Thomas 15:38, 6 July 2006 (UTC)
I couldn't immediately tell what objection you're referring to, by skimming the talk page. Is it "Infinite tidal forces simply do not exist at the S R location"? Tidal forces do indeed approach infinity as you approach the singularity (they go as 1/R^4), but nothing in the article is about the singularity. The article is about the horizon, so I can't figure out what the complaint actually is. Also, I am baffled by this initialism SR. What does it stand for? Usually in relativity, SR means special relativity, but clearly here it refers to some feature of black holes. What is it? -lethe talk + 16:22, 7 July 2006 (UTC)
Schwarzchild radius, I guess. You're right it should be explicit. --Michael C. Price talk 16:27, 7 July 2006 (UTC)
Of course the article should be explicit, but it's OK for people to use jargon on the talk page. I've just never seen this initialism before. OK, SR means horizon. I don't like it, it seems to limit us to horizons nonrotating uncharged static classical black holes (the Schwarzschild solution), but at least now I know what anon is saying. Thank you, Michael, for cluing me in. -lethe talk + 16:35, 7 July 2006 (UTC)
The anon thinks I'm claiming infinite tidal forces in the article. I'm not, and have made this clear numerous times. I _do_ claim that a rigid rod that is stationary with respect to a distant observer that is placed through the horizon would experience infinite tensile forces (in addition to falling apart because photons couldn't propagate between all parts of it). The anon disagrees. It's possible that I'm mistaken, but I trust the GR crew here more than I trust an anon. --Christopher Thomas 16:27, 7 July 2006 (UTC)
So you're looking for backup on this assertion, for example: the boosting force to keep your rocket ship stationary (with respect to asymptotic Minkowski space) approaches infinity as you approach the horizon. Yeah, I'm pretty sure that is correct. -lethe talk + 16:38, 7 July 2006 (UTC)
Lethe is right, I beleive. The anon seems to be saying that, in the reference frame of the person holding the rigid rod, the rod would not be long enough to actually cross the event horizon. Err.. indeed this is confusing. Basically, the anon is claiming that, if I unreeled a very very long spool of "steel tape" (ruler) down towards the event horizon, the tip of the ruler would never actually cross!? In the frame of a distant observer, the rules on the ruler would appear to get more and more compressed as the tip approached the SR (swar. rad). From the point of view of an obsrever hanging from the end of the ruler, the SR appears to "very far away". I think anon might be right, because that's how I remember it being taught in school. So maybe everyone is right? Although the forces would get infinite for the person hanging off the end of the ruler, fortunately, the person hanging off the end of the ruler can never get near enough to the SR to feel those "infinite forces". The closer he tried to get, the farther away the SR would get, the greater the forces would get, but he'd never actually get there. He'd have to "let go" and fall in order to fall in; but, while falling the forces would no longer be actualy infinite. The infinity is "potential" not "real", the falling observer does not feel infinite tensile forces. Only the rocket ship attempting to stay away from SR exteriences the need for more and more and more thrust, and unbounded amount of thrust, to keep at a safe distance. linas 00:03, 8 July 2006 (UTC)
I.E. there is no actual infinity, because either the ruler breaks and falls in (and feels no infinite force on crossing the SR), or the ruler is infinitely strong, in which case the unwary holder of the ruler will eventually feel a force that overwhelms his grip/ his rocket engines, and will have to cut the ruler free and let it fall. At no point does the ruler experience infinite force (before contact with the essential singularity). At no point does the non-falling ruler ever actually cross the SR, and a non-falling ruller can never be made long enough to cross the SR, because, in the non-moving ruler's reference frame, the SR is infinitely far away. linas 00:42, 8 July 2006 (UTC)
I'm puzzled by your (apparent?) statement that the ruler does have to be infinitely strong, but that the force is finite. That the non-moving ruler measures the horizon as infinitely far away is more reasonable, but that would lead to force on the ruler tending towards infinity as you integrated force along its (infinite) length, unless something strange was going on. This also seems to say that the situation where a non-falling ruler exists that crosses the horizon from the viewpoint of a distant observer can't be constructed/described, which seems odd to me. To see why I'm confused about this, consider the related situation of a rigid rod that, from the distant stationary observer's viewpoint, appears be stationary and to connect the distant observer to the singularity, and spell out to me how the rod is described in the various relevant regions. I'm really wishing my math was good enough to see all of the implications involved directly, as this really seems to be a coordinate systems issue more than anything else. --Christopher Thomas 02:45, 8 July 2006 (UTC)

Enough with the SR abbreviation, linas. I'm glad MCP told me what it means, but that doesn't mean that we have to start using nonstandard notation. -lethe talk + 04:21, 8 July 2006 (UTC)

Why would the dude hanging off the end see the horizon as far away? I think you should be able to lower him right up to it (assuming infinite tensile strength). -lethe talk + 04:31, 8 July 2006 (UTC)
Because the hanging dude is radially contracted he sees the horizon as infinitely distant. --Michael C. Price talk 06:53, 8 July 2006 (UTC)

--Michael C. Price talk 16:25, 8 July 2006 (UTC)

Michael is right. In fact, this whole confusion has a historical basis: when Schwarzschild first published his result, the initial interpretation was of an actual singularity at the SR. Later, when it was realized that a free-falling observer felt nothing unusual on crossing the SR, that's when the true debate started. To go back to Chris Thomas question about math: in the Schwarzschild metric, the spatial distance goes as 1/(1-R/r) and as r approaches R, the distance becomes infinite. That's why the event horizon is infinitely far away for an observer attempting to hover above the black hole. The observer is accelerating away from the black hole, accelerating at precisely such a rate that a constant position is maintained with respect to the black hole: this is what "hovering" means. In a way, this makes common sense: if you're trying to run away from something, accelerate away, you shouldn't be surprised that the something becomes "far away" as you run away.

There is a way to extend a finite length rod so that it crosses the SR. Suppose I had many thousands of miles of fishing line, with a little weighty hook on the end. I maintain a safe distance away from the black hole, where the gravity is not particularly strong, and start reeling out the fishing line. Suppose I reel it out so that the hook at the end goes into free fall, and crosses the SR. Because the weight (and line) was free-falling, I did not need an infinite length of line to pay out, before having the hook cross the SR. I now give the line a tug, hoping to pull the fish-hook out. As I tug on the line, a stress wave starts propagating down the line, moving more or less at the speed of sound. As the stress wave approaches the black hole, the stress becomes increasingly large; at some point, outside of the SR, it becomes so large that the line snaps, and the hook falls in the rest of the way. There's no "actual" infinity, because the fishing line never felt an infinite stress. It broke first, and after it broke, it felt only a small stress until it hit the true singularity. linas 16:57, 8 July 2006 (UTC)

Apparently I haven't made the scenario I'm trying to discuss clear enough. I'm looking at the _limit_ as tensile strength of the line approaches infinity, and the rate of initial lowering approaches zero, and so on and so forth, of the forces required to maintain the scenario described. Stating that the line snaps, rod breaks, or what-have-you violates the constraints of the question. As far as I can tell, for nonzero cable mass-per-unit-length, the tensile force on the cable tends towards infinity (with a description that was different from my original picture). Per discussion on talk:event horizon, we mainly seem to be arguing about terminology, and it's moot point anyways because I'm satisfied with your rewrite of the section involved. --Christopher Thomas 22:45, 10 July 2006 (UTC)

## Afshar POV

User:Afshar has reverted a POV tag on Afshar experiment on the grounds that it was anonymous. Could an admin revert/add it to make it "official"? --Michael C. Price talk 06:13, 6 July 2006 (UTC)

On the talk page, another user says there is no NPOV problem and has removed the notice. If you, or the anon, disagrees, feel free to use the talk page to discuss it. An NPOV notice without any attempt to discuss and resolve doesn't accomplish much. -lethe talk + 06:25, 6 July 2006 (UTC)
Hmm.. I see also that in the section of the talk page immediately preceding Sededeo's, you did engage in discussion about the issue. I apologize for the above comment which may have been superfluous. -lethe talk + 06:43, 6 July 2006 (UTC)
It's worth noting that nothing an administrator does, contentwise, is more "official" than anyone else. Anons have equal standing with other users as well; in practice they're often ignored if they do something controversial without leaving an explanation on the talk page, because it's often impossible to engage them in discussion later. The upshot of all this is that you can restore the NPOV tag as well as anyone else. (Discussion, as lethe notes and you apparently already knew, is also important for such tags.) -- SCZenz 08:03, 6 July 2006 (UTC)

The discussion with Afshar is, as expected, going nowhere. Linas has suggested that everybody agree that the whole article be rewritten from a decoherence POV, but given that Afshar can't understand the basic idea of OR, this seems doomed. Anyway I updated the critiques section with nod to the decoherence POV. I'm not hopeful that Afshar will respect Wiki policy and let it stand. --Michael C. Price talk 18:31, 7 July 2006 (UTC)

As expected, he reverted it. --Michael C. Price talk 21:12, 7 July 2006 (UTC)
I did not mean to suggest that the article be re-written from the decoherence pont of view. I wanted to suggest that Afshar study decoherence in his own spare time, and write about it in some other forum, ideally in a journal, and not here. linas 23:33, 7 July 2006 (UTC)
The article has been in an acceptable shape for quite a while, the POV tag is undeserved. I do not think amateur debunking attempts in the critique section would be appropriate at this time. If there is a critique that is posted off-site, and is somewhat deeper and more insightful than a few paragraphs of hand-waving, then a reference to it can be included. But short, hit-n-run critiques aren't helpful. linas 23:37, 7 July 2006 (UTC)
I disagree -- see my response on the Afshar experiment talk page. --Michael C. Price talk 23:45, 7 July 2006 (UTC)

There is a general issue here of the appropriateness of critique sections in controversial articles. And of their length. I have written a short one (for Afshar experiment) and had it deleted for being too short and handwavy. Yet if I lengthen it I am told that it still won't be appropriate and should be in an external link. It seems that no critique will be acceptable, yet other controversial articles have them (e.g. Bohmian mechanics - which I did not write, Modern Galilean relativity -- which I wrote). What gives? --Michael C. Price talk 00:55, 8 July 2006 (UTC)

Write it so that the section accurately represents or summarizes the four published critiques out there. People love to come by and take pot-shots at this topic. Going with this one variant, as opposed to the dozens of others, does not improve the article or add balance. linas 16:15, 8 July 2006 (UTC)
I have not just "come by" and taken a "pot-shot", I have been trying for weeks to get Afshar to see beyond his own POV. As for whether it improves the balance, I disagree with your POV. What part of:
The modern understanding of quantum decoherence and its destruction of quantum interference provides a mechanism for understanding the appearance of wavefunction collapse and the transition from quantum to classical. As such there is no need, in the decoherence view, for an a priori introduction of a classical-quantum divide as enshrined by complementarity. Any experiment that claims to violate complementarity needs to address this issue.
do you find "pure, unsubstantiated OR"? --Michael C. Price talk 16:25, 8 July 2006 (UTC)
Hmm. The standard mathematics of QM does not enshrine complementarity. The Copenhagen interpretation does enshrine wave function collapse. Any experiment that claims to violate complementarity is "boring" unless it somehow addresses the issue of wave-function collapse. Shall we add a sentence to the article stating that, as far as the Copenhagen interpretation is concerned, the Afshar experiment is "boring", because it sheds no light on wave function collapse? I suspect that the Afshar experiment is also boring if you view it in the light of the transactional interpretation of quantum mechanics; likewise for most of the other interpretations. The one place where the experiment seems to get possibly interesting is with the Englert relationship. There's lots of things that one might say that are true about the Afshar experiment; the mention of decoherence seems to be some random factoid that floats in from left field. I suppose we could start a list of factoids about the Afshar experiment, but I'm concerned that it could easily spiral out of control again. The other problem I had was that the sentences were vaguely insulting and condescending: that they're promoted as "general criticisms", when in fact, if one examines the record of the specific criticisms, they don't match these general criticisms at all. However, I tire of this debate. You've been championing decoherence recently, in many other articles, and, as a hammer, perhaps everything looks like a nail. Put yourself in someone else's shoes for a while: then the "general criticisms" just don't look very general at all, and they don't appear to accurately reflect the actual debate either. linas 17:34, 8 July 2006 (UTC)
Hi linas, I appreciate the change in tone. Yes, the Afshar experiment and my mini-critique are boring to anyone who has a good grasp of QM (such as yourself, for ex.) but what about the others whose POV you ask me to consider? Believe it or not they are precisely the target audience who require an accessible quick critique with links for depth as required. And just to correct a couple of misapprehensions, yes I think decoherence is important and not a random factoid, but I am hardly alone in this view. One other thing, you misunderstood what I meant by "general" vs "specific" -- which was my fault and I'll try to clarify that here and elsewhere. By "specific" I meant that many of the links were critical of specific aspects of the construction of Afshar's experiment, whereas my points were of a more general nature and insensitive to these minor details. And finally, the point that the experiment didn't violate the Schrodinger equation was something that had been highlighted on the talk page at least twice and in one of the external links. --Michael C. Price talk 19:42, 8 July 2006 (UTC)

## Scalars

A proposal to merge Scalar has turned into a protracted discussion of whether or not the term 'scalar' means the same thing in different disciplines. See Talk:Scalar. --Smack (talk) 05:13, 10 July 2006 (UTC)

## Massive insertion of Scientific American links

208.241.19.100 (talkcontribs) seems to be adding links to Scientific American articles about appropriate topics to a very large number of science- and physics-related articles. While these don't seem to be vandalism per se (being appropriate links), I'm not quite sure how to react to it, as it does seem to be linkspamming. Links are added roughly every 3 minutes, suggesting script assistance (or someone really bored). --Christopher Thomas 16:40, 11 July 2006 (UTC)

They're relevant, and Sci Am writes reasonably good popular articles that may be helpful/interesting to our readers. I very much doubt this is Scientific American trying to advertize itself, so I don't really think it's linkspam. I think it's just a user trying to improve the encyclopedia in a small systematic way, and succeeding. No action necessary unless there's something I'm missing. -- SCZenz 16:44, 11 July 2006 (UTC)
They continued after the first warning, I've given another. The IP is registered to Scientific American, this definitely qualifies as commercial spamming and needs to be watched. Femto 17:34, 11 July 2006 (UTC)
Even if it is linkspamming wouldn't Wikipedia readers benefit? SciAm is quite accessible. just be thankful it's not the Fortean Times. --Michael C. Price talk 17:42, 11 July 2006 (UTC)
I think the only thing we need to worry about is whether the links are to free articles. If WP policy would somehow require to unlink these articles, then IMHO, there is something strange about WP policy.--CSTAR
I disagree strongly with the above warnings. Links to relevant Sci Am articles are useful to Wikipedia, regardless of their source. -- SCZenz 17:59, 11 July 2006 (UTC)
PS When I looked at one of the linked SciAm articles, a advertising banner partially obstructed the text. Even though that obstruction is likely only temporary, in my view that is not a "free" link. --CSTAR 18:01, 11 July 2006 (UTC)
People can read the article. Do we really have a rule that says too much advertizing makes a link unacceptable? If so please point me to it. -- SCZenz 18:03, 11 July 2006 (UTC)
I'm not objecting to advertising accompanying the text. I'm objecting to advertising blocking the text. There is a policy against links to advertising.--CSTAR 18:06, 11 July 2006 (UTC)
This is how they display their articles, as many websites do. The blocking goes away after a short while. So the advertizing is a little bit obtrusive, it's not like there isn't an article there. I don't see the problem. -- SCZenz 18:09, 11 July 2006 (UTC)
Well, it's clearly a matter of interpretation. I think we should be hard-nosed. We should tell them: If you want links to your articles from WP, then you can keep your advertising so long as it doesn't obstruct the text. That's a fair bargain, in my view.--CSTAR 18:15, 11 July 2006 (UTC)
Even then, there's only one side that truly benefits from bargaining over unfree content for external linking. The "content instead of links" rule is there for a reason in the free encyclopedia. It holds true not only, but especially, for content providers that will have a commercial or promotional gain from links. Femto 18:36, 11 July 2006 (UTC)
Since this is turning into a policy debate, may I suggest moving the discussion to WP:AN/I to get more eyes on it? --Christopher Thomas 20:46, 11 July 2006 (UTC)
I've gone ahead and added a section there at Wikipedia:Administrators' noticeboard/Incidents#Apparent SEO/Linkspam to Scientific American articles with pointers to prior discussion here and at the IP's talk page. GRBerry 18:59, 12 July 2006 (UTC)

While I may have your attention, may I re-open the case of the xstructure links, see [1]? --Pjacobi 18:27, 11 July 2006 (UTC)

• I haven't yet decided what I think about this; the links themselves are fine and contribute to the articles, but I generally consider it to be bad form to link to your own sites, and WP:NOT a collection of external links. There's also the slippery-slope problem of where to draw the line. What happens when the next magazine want to link their content into article? Furthermore, as noted, this appears to be either bot assisted or a dedicated effort (paid by SciAm?) to systematically link a *large* number of article, which in my mind smacks of search-engine optimization. I guess that's the part that really rubs me the wrong way. --Alan Au 02:24, 12 July 2006 (UTC)
Just to provide some references for this discussion, first, yes there is a guideline that indicates sites with objectionable amount of advertising should be avoided: WP:EL, "links to normally be avoided", point #4. Coincidentally, also covered in the same point are "links that are added to promote a site."
If these links are being added by a bot, this taints their additions even further. Per WP:SPAM, "external links spamming": "Spam bots should be treated equivalently as vandalbots. Edits by spambots constitute unauthorised defacement of websites, which is against the law in many countries, and may result in complaints to ISPs and (ultimately) prosecution." What I don't see anywhere is a qualification there that says "unless the links could be useful".
One other guideline reference:
• WP:EL, "links normally to be avoided": "A website that you own or maintain, even if the guidelines above imply that it should be linked to. This is because of neutrality and point-of-view concerns"
SEO is a serious problem, and we ought not ignore the possibility that is is exactly what we're looking at. Even if the articles are relevant, Wikipedia is not here to promote another website, which is exactly what SEO does. Considering that these edits are coming from Sci Am themselves, and are occuring between the hours of 9-5 EST (the time zone that SciAm's located in [2]), does anyone really think that this is some editor trying to help out Wikipedia on his/her own time? --AbsolutDan (talk) 04:12, 12 July 2006 (UTC)

Based on the edit histories, this is clearly a spambot at work, and so sets a bad precedent. As long as the SciAm article provides substaintially more, or better information than the WP article, having such a link is acceptable. However, when a linked website, any linked website, is information-poor as compared to WP, it should not be linked. Its not obvious that some of the SciAm links are really head-n-shoulders above what's in WP. linas 18:31, 12 July 2006 (UTC)

This is an ugly case and bad precedent. Unfortuntely, just like in the law, it is usually the bad cases that go to court. If there is a bot, it is human attended. I haven't found a clearly irrelevant linkage and it is 3-5 minutes per article, which isn't unattended computer speed. But it appears as a linkspam campaign, and ought to be treated as such. If the articles are that valuable, someone not associated with SA will eventually find a reason to add them again, we should take them out. GRBerry 18:56, 12 July 2006 (UTC)

This is pretty much what we had already inferred. Although I personally think that useful links are a good thing, there was substantial disagreement about this linking. I am going to paste your comment into one of our policy discussion forums; hopefully we'll reach some consensus on this and let you know. -- SCZenz 18:46, 13 July 2006 (UTC)
See Wikipedia:Village pump (policy)#Scientific American linking. -- SCZenz 19:03, 13 July 2006 (UTC)
FYI AciAm was not the first. A couple of authors from the Russian on-line differential equations website spammed a number of articles on differential equations a year ago. For the most part, the links were relevant, if poorly formatted. At this point, my major concern is that they at least format the inserted links properly, instead of adding to the mess that is known as "external links" (which mess I would dearly like to see abolished). linas 01:35, 14 July 2006 (UTC)
Reliable external sources can increase quality and I do use this tool. In my opinion it is better to emphasize some standards for external links (see them as freely available non-wikipedia article) if they do not reach at least good article criteria or a barnstar, delete them. Of course they should have some concern with the topic and POV should be avoided. That somebody tries to put here his own research should not be objected as long as he obeys the rules and gives a fair presentation (what others did and do) of the topic. (visiting military history member) Wandalstouring 16:03, 14 August 2006 (UTC)

## Quantum Theory Parallels to Consciousness

Anybody feel up to tackling Quantum Theory Parallels to Consciousness and making it into something encyclopedic, if that is even possible? Anville 17:03, 13 July 2006 (UTC)

I don't think it is possible. It should most likeley be deleted. --Philosophus T 17:15, 13 July 2006 (UTC)
A quick glance at the references shows at least half of them to fail WP:RS. I'd be tempted to just AfD this article, but I don't feel up to another pseudoscience battle right now. In an ideal world, the article would just neutrally describe the fact that a small but (hopefully) notable number of people believe that quantum mechanical thought processes allow ESP, but good luck getting the article into anything resembling that form. --Christopher Thomas 17:18, 13 July 2006 (UTC)
Is there already a decent discussion of this sort in some article? We could probably turn this one into a redirect. Anville 17:26, 13 July 2006 (UTC)
Yes, anyone object to redirecting it to Consciousness causes collapse? --Michael C. Price talk 17:26, 13 July 2006 (UTC)
Yes, I do. The articles do not appear to be related. One is about consciousness causing collapse, the other is about psychic nonsense. By the way, the Consciousness causes collapse article seems quite bad as well. --Philosophus T 17:33, 13 July 2006 (UTC)
No disputing that, but it's less bad. --Michael C. Price talk 17:47, 13 July 2006 (UTC)
It's already up for AfD. --Philosophus T 17:29, 13 July 2006 (UTC)
On which I voted to delete. I don't feel like trying to turn this dreary pageant of bad thinking into something scientific and encyclopedic. . . maybe I'm just getting old? Anville 17:31, 13 July 2006 (UTC)
Unscientific yes, but unencyclopedic? Eugene Wigner published stuff on consciousness and QM. So I say redirect and the number of pseudoscience articles is reduced by one. --Michael C. Price talk 17:36, 13 July 2006 (UTC)
The most sensible redirect I can find is to point the "Parallels" page to Orch-OR, another page which needs serious de-POVing by a real science person. Anville 17:40, 13 July 2006 (UTC)

## Yet another AfD

An AfD has been started for Cognitive-Theoretic Model of the Universe. Evaluate as you see fit. --Christopher Thomas 15:29, 14 July 2006 (UTC)

That's quite an overbearing AfD page. The sockpuppets are out in force today, I see. Anville 18:37, 14 July 2006 (UTC)
You're doing a great job of flagging them so far. A batch-AfD of related pages might be in order once the fuss dies down for this one (unless of course any of them happen to actually be encyclopedic). --Christopher Thomas 19:28, 14 July 2006 (UTC)
Judging by the media coverage metric, the guy who cooked up the Cognitive-Theoretic Whizbang of the Wangdoodle may be notable. Once this furor dies down, we could probably roll all the related pages into his biography and leave a few redirects. I don't think The Ultranet and Mega Foundation can or need to stand on their own, for example.
Side note: if all the people involved with this guy's high-IQ societies are as unpleasant as the sockpuppets mucking up this corner of the Wikipedia, I'm sure glad I'm dumb. Anville 19:34, 14 July 2006 (UTC)

Well, as the redlink above shows, the CTMU was deleted. However, it has been proposed for undeletion (can you believe it?) over here. Why can this unpleasantness just not end? Byrgenwulf 07:40, 20 July 2006 (UTC)

Undoubtedly one factor is the unpleasantess and lack of civility from both sides. Perhaps a lesson for the future for all concerned. --Michael C. Price talk 09:24, 20 July 2006 (UTC)

## Problems at string theory

The editor zelos (talk · contribs), who also edits as 217.208.244.136 (talk · contribs), has been aggressively removing information he considers to be unfounded "rumour" from string theory and other articles. For all I know he may be correct, but he isn't providing citations, just re-inserting when reverted and making statements on talk pages. If additional people familiar with the topic could take a look at the (short) edit histories of these two users and sanity-check them, it would be greatly appreciated. In the meantime, I've left messages attempting to clue him in. --Christopher Thomas 19:06, 15 July 2006 (UTC)

Linas pointed out that the tone of the statements at string theory was a bit sensationalistic, so I replaced it with text based on the much more neutral statements at Gabriele Veneziano (which the above editors also don't like). --Christopher Thomas 21:54, 15 July 2006 (UTC)

## Definition of physics

I wish to propose changing the definition of physics on the physics page. The current definition (as of 16 July) is:

Physics…is the science of Nature, from the quarks to the cosmos. Physics deals with the elementary constituents of the universe and their interactions, as well as the analysis of systems which are best understood in terms of these fundamental principles.

My main objections are that a definition of physics should be independent of our current description of it, and it is too vague: “from the quarks to the cosmos,” tells you nothing. I propose the following:

In everyday terms, physics is the science of the world around us that attempts to describe how objects behave under different situations. To illustrate, physics tells us that objects at rest like to remain at rest (Newton's First Law of Motion), or that all known processes increase the total entropy of the system and its surroundings (the Second Law of Thermodynamics).
You say "physics should be independent of our current description of it", yet now you are talking about Newton's Laws and thermodynamics.  ??? Just accept "from the quarks to the cosmos" as poetical if you have problems with quarks. --Michael C. Price talk 23:27, 15 July 2006 (UTC)
However, a more formal definition would be that physics is merely the description of, or the desire to acquire knowledge of, how physical objects interact, if they indeed do so. The word "interaction" is understood to mean the influence of one "physical object" on another such "physical object"; and "physical objects" are objects that have been observed to have "interacted" in some way with other such "physical objects". It should be noted that the definition makes no predictions about nature: it does not say what form the "interactions" take, or what the "physical objects" are.
Physics, as defined above, appears to be based on a circular definition between the terms "interaction" and "physical objects". To explain the reason for this, let us remark that we would like physics to be the description of how nature truly behaves, and, as a first attempt at a definition, this is what we may naively assert. However, such an ideal is not thought to presently be possible. If, as observed, no person (or more generally no "entity", which we do not elaborate further on, which can inquire about physics) has any prior, inherent knowledge of the true behaviour of nature, then they may only infer what laws are likely to be followed by nature solely through an act of observation. This conclusion inevitably leads one to accept that it is not currently possible to give any intrinsic meaning to the words "interaction" or "physical objects" that is independent of the other.

Krea 23:18, 15 July 2006 (UTC)

It needs some work, but I like your definition better. "the science of Nature, from the quarks to the cosmos" is meaningless. — Omegatron 23:26, 15 July 2006 (UTC)
Not meaningless, just an expression of the fact that physics is the fundamental empirical science of everything (as opposed to mathematics, which is tautological or, say, biology which has a narrower domain). --Michael C. Price talk 01:11, 16 July 2006 (UTC)

The first paragraph is merely an introduction for the lay, the more formal part is "independent of our current description of it". Any suggestions for improvement? Krea 01:09, 16 July 2006 (UTC)

Physics…is the empirical science of the fundamentals of Nature, i.e. of everything. --Michael C. Price talk 01:18, 16 July 2006 (UTC)
Ok, its not completely meaningless, but I don't think it's really required. Where do you want to put your suggested sentence? As an addition or a replacement?
Krea 01:22, 16 July 2006 (UTC)
A rewording of the opening sentence. I thought that was clear. --Michael C. Price talk 01:41, 16 July 2006 (UTC)
In everyday terms, physics is the science of the world around us that attempts to describe how objects behave under different situations; which it does through empirical observations with the ultimate aim of describing the entirety of nature. To illustrate, physics tells us that objects at rest like to remain at rest (Newton's First Law of Motion), or that all known processes increase the total entropy of the system and its surroundings (the Second Law of Thermodynamics).
Krea 01:33, 16 July 2006 (UTC)
May I suggest we take this to talk:physics and I'll see you there? --Michael C. Price talk 01:41, 16 July 2006 (UTC)
I've copied this section to talk:physics. Anyone interested can take the conversation there. --Michael C. Price talk 01:54, 16 July 2006 (UTC)

## Hyperwarp 6D & AfD

A wonderfully exciting new theory of spacetime, which solves all the problems faced by modern physics by positing an extra two temporal dimensions. Designed by a "chaos magician", this one is quite bizarre. I have added tags, infobox, etc., but it's going to need a lot of help. Moreover, since it isn't published anywhere except on the chap's own website (with all of 608 google hits); should it be here? Byrgenwulf 13:53, 16 July 2006 (UTC)

As I just said on the article's Talk page, Hyperwarp 6D would be a good title for an arcade game, but as pseudophysics, it's not even widespread enough to be notable "quantum flapdoodle". AfD is only a template away. . . . Anville 14:11, 16 July 2006 (UTC)
In progress. Byrgenwulf 14:12, 16 July 2006 (UTC)

Right, the AfD nomination is here, for anyone who's bothered. Wikipedia:Articles_for_deletion/Hyperwarp_6D Byrgenwulf 14:23, 16 July 2006 (UTC)

## Metric expansion

Help us edit, expand, and reference a new article on Metric expansion of space. --ScienceApologist 18:18, 16 July 2006 (UTC)

I'd like to, but I'm not qualified. (Brits will understand if I say that I failed physics A-level. Well, I did pass it the second time around.) Still, I think I recognize rather silly objections to certain aspects of ScienceApologist's work when I see them. One or two more people well up in physics may wish to chime in there. -- Hoary 14:41, 18 August 2006 (UTC)

## Wikiproject on Physical Chemistry

There is a proposal on Wikipedia:WikiProject/List of proposed projects at the bottom of a long list for a Wikiproject on Physical Chemistry. Discussion on it is at Wikipedia talk:WikiProject Chemistry. This would look at all articles in the general area of Physical Chemistry and this includes a lot of articles that are more linked to Physics articles. The project will be a sub project of Wikipedia:WikiProject Chemistry but maybe it should also be a sub-project of Wikipedia:WikiProject Physics. Please comment on all aspects of this proposal. --Bduke 08:40, 18 July 2006 (UTC)

## Wikiproject on Spectroscopy

I just started a new WikiProject for WikiProject Spectroscopy. I am hoping that efforts can be focused from this project and WikiProject Chemistry. I am new to editing and may have taken too big of a bite. --Tjr9898 00:52, 21 July 2006 (UTC)

## AfD: Mass of the observable universe

The article Mass of the observable universe is up for AfD: Wikipedia:Articles_for_deletion/Mass_of_the_observable_universe. It might be useful if some one with a cosmology background can inform about the hoax/original research status of this article. -- Koffieyahoo 05:27, 21 July 2006 (UTC)

## Request for physics input at physics/chemistry interface

I am looking for quality rational input from a very physics perspective on physics related articles that have components that fall at the interface between physics and chemistry. It does involve content disputes however I am not looking for mediation. I am interested in including your perspectives in my position on the issue. In other words I am very open minded and actively seeking input. It is important to understand the difference between truth and verifiability and to be able to parse the two. Please contact me on my talk page to start collaborating on this and hopefully other interfacial articles.--Nick Y. 22:29, 21 July 2006 (UTC)

This is the third request for physicists to assist at the physics/chemistry interface - see the two proposals for new WikiProjects above. There has not been a single response to any one of the three as far as I can see. Are no physicists here interested in helping chemists at the interface? --Bduke 02:11, 28 July 2006 (UTC)

I'm afraid I'm not knowledgeable enough in these fields to contribute usefully. User:DV8 2XL would have been a good choice, but he seems to have left Wikipedia (after the depleted uranium debacle). --Christopher Thomas 02:59, 28 July 2006 (UTC)

## Time again

There's now a discussion going on at talk:time about revising the introduction and definition of time (again). It could use review by actual physics-types, as this article has always had a high amount of attention from philosophers, and that seems to now be exclusively the case. --Christopher Thomas 05:47, 23 July 2006 (UTC)

Wow, you weren't kidding. I loved the line, "Christopher Thomas, you are saying that a phenomenon can exist without a brain in which it appears as a phenomenon? That would be a non-phenomenal phenomenon. Time, though, is not a phenomenon. Time is the possibility of an animal brain's experience of the succession of phenomena." Zippy! Sadly, reading the article and talk page left me numb and useless for further editing today. I'll try this weekend. Adelord 21:40, 27 July 2006 (UTC)

## Need eyes on a merge attempt

Alcubierre drive: I've got Spacewarp and Alcubierre metric merged in where it could best fit, but it needs serious verification and cleanup by people who have degrees or books handy. Cwolfsheep 03:06, 24 July 2006 (UTC)

## Flow of contribs is mangled

19:06, 23 July 2006 Cwolfsheep (Talk | contribs) (Need eyes on a merge attempt)
01:37, 23 July 2006 Bduke (Talk | contribs) (Phys Chem Project started)
01:17, 23 July 2006 MichaelCPrice (Talk | contribs) (?Yet another AfD)
^^^^^^^^^^^^^^^^^^^problematic edit
01:11, 23 July 2006 Hillman (Talk | contribs)
01:00, 23 July 2006 MichaelCPrice (Talk | contribs) (?Yet another AfD)


When 01:17 was made, an unarchiving, it wiped out some Hillman text, inadvertently. Please restore; if you need help, maybe one of your Megafriends can help. --GangofOne 22:43, 24 July 2006 (UTC)

A massive linking campaign seems to be underway by 202.137.162.250 (talk · contribs), who is adding links to articles about nuclear rockets and interstellar travel at high speed (top speed: twice a minute, though not necessarily bot assisted). I'm in the middle of a deadline crunch at work, so I'm not in a position to vet these changes right now. Anyone care to take a look at it? --Christopher Thomas 16:20, 27 July 2006 (UTC)

Some of the links seem to be (sometimes marginally) pertinent to the topics of the articles - I'm leaving those; but there is also a link to some web-forum ([http://www.atomicrockets.com "Atomic Rockets"]), which pops up on each edit, and which I am removing from all the articles. Common courtesy says, I think, to put a new link, especially one of that nature, at the bottom of the list, after all the more relevant ones (like to NASA sites and things). Byrgenwulf 17:33, 27 July 2006 (UTC)
A (very) new user has left a note on my talk page claiming that this is IP address belongs to a banned user by the name of Wayne Smith (flying fox (talkcontribs), blocked for vandalism and name-calling after disputes stemming from Project Orion (nuclear propulsion). I have no way of assessing the truthfulness of this accusation. I directed them to AN/I. --Christopher Thomas 02:57, 28 July 2006 (UTC)
User:Universe Daily sock and one of his spam links. They all lead to the same website. I removed one from a salt water nuclear rocket article. They're usually deceptive in their naming, and multiple may be added at once with different address that go to the same forum. He's indef blocked by some admins. If you see lots of wierd spam being added to physics articles, drop us a line over at the WikiProject Spam talk page for some investigation. Kevin_b_er 07:30, 8 August 2006 (UTC)

From time to time I have seen angry cranks complain in AfD that asking others to comment in a physics-related AfD is somehow inappropriate. A possibly relevant ArbCom precedent which might be worth bookmarking:

Aggressive point-of-view editing can produce widespread reactions as editors attempt to combat an outbreak of it, mobilizing others to join the fray. While this creates the appearance of disorder, it is better seen as an attempt to deal with a refractory problem.

I didn't previously know about Wikipedia:Arbitration_policy/Precedents. Some editors feel that precedents from previous ArbCom cases should guide admins in other cases which have not been taking to RfA, but one admin I asked to comment says he does not agree with that claim. Still, from the viewpoint of citing community norms and practices wrt say WP:IAR, the above link might be useful.

Wikipedia has become a regulatory thicket, complete with an elaborate hierarchy of users and policies about policies.

— Stacy Schiff, KNOW IT ALL Can Wikipedia conquer expertise?, New Yorker, July 31, 2006

Indeed ;-/ ---CH 02:02, 28 July 2006 (UTC)

Isn't one of the main purposes of this page to ask people for help? And just wherefore is a dividing line drawn between AfDs and all other pages?? Sheesh. I guess expecting good sense from "angry cranks" is a bit much to ask. Anville 02:45, 30 July 2006 (UTC)

Hi all, I think you might be interested in this MfD. ---CH 23:56, 28 July 2006 (UTC)

## Problematic articles relating to time and spacetime.

A number of articles have been recently created by Alvatros (talkcontribs) on topics relating to time and spacetime. These articles for the most part have content that is a mixture of poorly phrased duplication of ideas from time, spacetime, and quantum gravity, and of original research. Problematic contributions to dimension have also been made. As this is a new user, the edits are probably being made in good faith, but the mess still needs cleaning up. I'll try to explain WP:NOR on this user's talk page. --Christopher Thomas 21:05, 1 August 2006 (UTC)

Quantic space-time has been recreated. I'm attempting to explain, for the second time, that this isn't the place for original research and that he should go through deletion review instead of just recreating the content, but I don't seem to be getting through. --Christopher Thomas 00:23, 2 August 2006 (UTC)
Wow, that was quick :). Someone's watching the "speedy deletion" queue.--Christopher Thomas 00:25, 2 August 2006 (UTC)

After many, many attempts, this user is showing signs of being willing to learn how to interact with Wikipedia. Still quite a long ways to go, but further disruption should be minimal (I hope). --Christopher Thomas 04:11, 2 August 2006 (UTC)

## Black holes and MECOs

Kazvorpal (talkcontribs) keeps modifying the black hole article to emphasize MECOs. I've already reverted once before. Someone else can take a look at this, as I'm going on vacation soon. --Christopher Thomas 18:01, 2 August 2006 (UTC)

ObCaveat to check carefully to make sure any genuinely valid points are kept, of course. --Christopher Thomas 18:59, 2 August 2006 (UTC)
The MECO article needs severe cleanup: am embarking on a bit of that, but by Lucifer some people need to learn what a bibliography is. I have added a link to MECOs in the article. There was apparently a New Scientist article about it, but New Scientist does have a tendency to blow new borderline discoveries out of all proportion with wow-gee-whiz reporting. Google gets about 30 000 hits for ("MECO" "black hole") but about 20 000 000 for "black hole": as yet they surely do not merit mention as a serious alternative to black holes? (Have posted this same one on the black hole talk page) Byrgenwulf 19:35, 2 August 2006 (UTC)

## "Symmetrical Relativity"

There's a new article called Symmetrical Relativity, which I assert is original research and hence unsuitable for Wikipedia. If you have a background in the subject your review and opinions would be welcome on the talk page. Thanks! --Craig Stuntz 17:18, 3 August 2006 (UTC)

First of all, the article is wrong: special relativity is not the same as general relativity, and GR is indeed founded upon the principle of equivalence (what the article confusingly calls "the General Principle of Relativity"). After it begins in the wrong, it segues into being just confusing:
Under unconstrained general relativity, black holes cannot exist. Black holes are defined as objects whose escape velocities exceed the speed of light. It is well known in special relativity that objects cannot accelerate to the speed of light, so the symmetrical theory of general relativity bars objects from acquiring an escape velocity in excess of the speed of light.
Er. No.
My cruel and heartless recommendation as a card-carrying physicist bastard is WP:AFD, on the basis of WP:NOR. Anville 18:08, 3 August 2006 (UTC)
Well, it seems that our intrepid researcher hasn't even made his mind as to what his supertheory is called yet...a new article, absolutely identical, has sprung up at Relativity (consistent with the general principle).
Wikipedia, last time I checked, isn't a published of cutting edge scientific research like this. What fools the entire corpus of physicists this last century have been, to not realise that general and special relativity are symmetric, and therefore the same thing.
So we have two articles for deletion, it seems. Can we make them symmetric, or should we just combine them into one grand unified AfD? Byrgenwulf 18:34, 3 August 2006 (UTC)

## Quantum =/= Modern Physics

The physics article is under attack by an anon, 61.1.232.81, who confuses modern physics (a somewhat loose term) with quantum physics and shows no inclination to discuss things. I'd revert them again but I'll be bumping up against 3RR soon. --Michael C. Price talk 12:04, 5 August 2006 (UTC)

## Thermodynamic temperature

This article has a strange preamble that seems to serve no purpose at all other than being ugly and unencyclopedic. Do you think it is needed? Loom91 18:26, 6 August 2006 (UTC)

## VFD List of non-mainstream theories underway

Please come and vote :) Count Iblis 20:51, 6 August 2006 (UTC)

## Physics Article WIP proposal

I thought it would be pertinent to post this here given that it is the project page. Over the past few months the Physics article has suffered from a lack of focus and direction. Unfortunately the article is now judged by a number of editors to be in a relatively poor state. There is currently a proposal to start a full consensus based review of the article. That review and consensus process has been proposed here, editors thoughts on the proposal and participation in the WIP review of the article would be much appreciated. It disappoints me that an article on one of the fundamental sciences here at wikipedia is in such a relatively poor state, and I hope other editors can have a browse by the page to offer their views and hopefully participate. Thanks, SFC9394 22:22, 7 August 2006 (UTC)

## Edit war at "Photon"

(Pardon me for writing here since I am normally a mathematician rather than a physicist.)
There is an edit war going on at the article Photon and to a lesser extent at Mass in special relativity between User:Ati3414 on one side and User:Dicklyon with several others (including myself) on the other side. The issue is whether a composite system, such as a box containing a "photon gas", has a mass which includes contributions from the energy of the massless components, that is, the photons. My side says yes. Ati3414 says no. Both sides keep reverting each other. Please intervene. JRSpriggs 06:30, 9 August 2006 (UTC)

I suggest another one-month ban might be appropriate for Ati3414. --Michael C. Price talk 08:55, 9 August 2006 (UTC)
Hi, this is Willow. As far as I can tell, the debate at Photon seems to devolve to one of pedagogy: how to explain to lay-people the apparent contradiction that photons are massless, yet the absorption of a photon increases the inertial mass of the absorbing body. I tried to lay out the present understanding of physicists of the Talk page Talk:Photon, but the atmosphere there is rather hot and I'm not sure if I'm getting through. I'm really, really busy at home, too. Can someone more experienced please help out? Thanks muchly! Willow 20:29, 9 August 2006 (UTC)
OK, the "mass of the photon" debates at Talk:Photon seems to have been resolved; the text of the debate has been archived in five subpages listed at the top of Talk:Photon. Unfortunately, there was a Wiki-casualty; User:Ati3414 has been banned indefinitely.
In a curious sidelight of the debate, a few editors ascribed relativistic mass to massless particles such as the photon. I had never heard of that being done, so I surveyed ~20 common physics textbooks and review articles from 1921 to the present (as well as the original articles by Einstein and Planck) and have not been able to find a single instance where "relativistic mass" was applied to massless particles in the scientific literature, although the heuristic derivation of the gravitational red shift might be construed as such. But given my all-too-limited search, I'm ready to believe that I missed something. Is anyone aware of such an application in the scientific literature — you know, in an article of Phys. Rev. or another peer-reviewed physics journal? Thanks for your help! Willow 22:02, 16 August 2006 (UTC)
I don't have any physics journals lying around the house (I'm a mathematician), but I found something in SciAm. See my note at talk:photon#Reference for application of relativistic mass to photon. --Trovatore 04:32, 21 August 2006 (UTC)

## Milne cosmology

User:JDoolin is pushing his "Milne cosmology" into inappropriate physics articles e.g. [3]. Keep an eye on him, guys. --Michael C. Price talk 19:20, 9 August 2006 (UTC)

Phew! Thanks for the warning, that would have been bad. Exactly what is the danger here? User:JDoolin 20:22, 16 August 2006 (UTC)

## WP:AfD: Electrical Discharge Machining in Space

Oops. I apologize for accidentally removing this section; I was trying to get rid of a bit of junk inserted at the very top which I noticed had interfered with the Archive box. I didn't notice that this had been inserted with the same edit — mea culpa. I have commented on the AfD now. Again, many apologies, and best wishes. Anville 17:17, 10 August 2006 (UTC)
No worries. Sorry, looking at the history it appears that junk came in with my edit though I don't recall entering any templates up there. Anyhow, thanks for participating in th AfD -- it's good to have some project folks looking at it. zowie 17:51, 10 August 2006 (UTC)

## Strange edits at Modern geocentrism

User:Lucaas, who I believe to be a sockpuppet of User:Tercross, keeps making edits at Modern geocentrism that seem nonsensical to me. I've reverted three times now. --LambiamTalk 22:32, 10 August 2006 (UTC)

## Special relativity - simple explanation

An article called Special relativity - simple explanation was created by a user today. I marked the article for prod stating the reason "The topic of this article is already covered by Special relativity and Introduction to special relativity". The prod was challenged by the user claiming that the introduction article is too technical. Please see the discussion on Talk:Special relativity - simple explanation. The user has posted a message at Talk:Introduction to special relativity too. It would help if some members of this project can handle the issue. Thanks, and I hope I have come to the correct wikiproject. - Aksi_great (talk - review me) 13:27, 11 August 2006 (UTC)

## Discussion at talk:quasar

A new editor is posting on talk:quasar asserting that the supermassive black hole explanation of AGNs is a "crock of shit" and accepted only as the least ugly of several bad explanations. If any lurking astrophysicists can spell out the evidence for him/her, that would potentially forestall difficulties with the article itself. My understanding was that this model was nearly universally accepted, due to the sources being both compact and distant, and relativistic jets being a well-documented effect. --Christopher Thomas 06:51, 13 August 2006 (UTC)

Still going. Another new user has chimed in supporting the first. An edit to the article by this user has been reverted (not by me).--Christopher Thomas 17:02, 18 August 2006 (UTC)
Revert war appears to be in progress. --Christopher Thomas 21:08, 18 August 2006 (UTC)

This problem is ongoing, with Lengis (talkcontribs) and Malamockq (talkcontribs) being the primary antagonists. When pressed for literature references, one of them cited an anti-evolution web page. I'm attempting to explain how WP:RS in this context. More help would be greatly appreciated.--Christopher Thomas 04:32, 19 August 2006 (UTC)

I've posted about this problem on WP:AN/I, as Lengis (talkcontribs) doesn't appear to be taking the hint from multiple editors reverting his/her contributions, and keeps reinserting the same material. Their latest source is a book from 1983 (i.e., more than two decades out of date). More statements from bona fide astrophysics types would be appreciated. --Christopher Thomas 02:12, 21 August 2006 (UTC)

## Help for Military History project

In the military history projects we have articles about weapons like bows, crossbows, ballistae, etc. Many people do believe a ballista shoots straight and a catapult for example in an eclipse. Well, it is simple mechanics, but I would appreciate if you find a way to add some explanations or links to explanations, so even the average reader gets some mathematical background. For bows, crossbows, etc. heavier projectiles have an increased efficiency in getting the stored energy from relaxing the material into their kinetic energy. If someone could write this in simple mathematics, it would make some people a lot smarter. There are also some mathematical models on the ideal construction of a bow, that should be beter explained by somebody concerned with physics. Of course, I have further ideas where we could make use of some help. Greetings Wandalstouring 18:29, 14 August 2006 (UTC)

Ballistics and trajectory would be good pages to link to. For transfer of energy and momentum to the projectile, I can outline the mathematics involved here, and the military history crew can apply parts of it where needed.
The key is that energy and momentum are two different values, with different applications. Energy would be most closely tied to the total cost or amount of work needed to fire a projectile, while momentum would be most closely tied to the amount of damage a projectile does to the target. For purposes of most weapons, these are calculated using classical mechanics as follows:
${\displaystyle E=\left({\frac {1}{2}}\right)mv^{2}}$
${\displaystyle P=mv}$
For a fixed amount of energy, a large, slower-moving projectile will have more momentum than a small, fast-moving projectile. For a fixed amount of momentum, a small, fast-moving projectile requires more invested energy than a large, slower-moving projectile.
For transferring energy and momentum to a projectile, three more equations help clarify things:
${\displaystyle E=Fd}$
${\displaystyle P=Ft}$
${\displaystyle d=\left({\frac {1}{2}}\right)\left({\frac {F}{m}}\right)t^{2}}$ (Corrected 16:32, 16 August 2006 (UTC))
If projectiles are accelerated with a constant force over a constant distance (as may be approximately the case with a gun barrel operating at maximum pressure, or a crossbow at maximum tension), the energy imparted to the projectile is the same regardless of the projectile's weight, but the larger projectiles are accelerated more slowly and gain more momentum. Most other projectile weapons that I can think of offhand end up delivering more or less constant energy, but I could easily be overlooking something. --Christopher Thomas 20:47, 14 August 2006 (UTC)
Is not the equation ${\displaystyle d={\frac {a\cdot t^{2}}{2}}}$ (including dividing by two)? With ${\displaystyle a={\frac {F}{m}}}$ and assuming that one starts at rest. Or am I missing something? JRSpriggs 06:56, 15 August 2006 (UTC)
You're right. I've made a suitable revision above. --Christopher Thomas 16:32, 16 August 2006 (UTC)
No pictures there. I am sure our clients do need things visually. Well, these are basics. Usually I tell these, the reader does not fully understand what it means, but math sounds good and he believes me the rest. Furthermore there are theoretical works on the ideal bow, do you know more about that? Wandalstouring 21:11, 16 August 2006 (UTC)
Not offhand, sorry. The mathematics are straightforward to analyze, but the upshot is the "fixed energy" picture outlined above. The strength of the bow arm material tells you the maximum amount you can bend it, the stiffness tells you how much Work (with a capital W) you have to do to bend it to maximum extent, and that gives you the amount of energy delivered to the projectile, independent of projectile weight. There's a loss factor based on bow geometry and so forth, but that's a constant. You get the same kind of situation pulling the bow back with any given strength of pull, instead of to its breaking point, with the amount of stored energy being a function of the force applied. --Christopher Thomas 21:28, 16 August 2006 (UTC)

## Remove "nuclear" from "Weak nuclear force"

I would like to standarize all articles to use the term "weak force" or "weak interaction" instead of "weak nuclear force", since we now know that it does not affect nuclear processes exclusively. (There's no nucleus in the process νe μ → νμ e, for instance.) I believe that "weak nuclear force" has also fallen out of common usage among physicists (although I haven't done a survey). Before I go on my little anti-nuclear rampage, would anyone like to object? --Strait 04:12, 15 August 2006 (UTC)

Just mention the old usage once for those who do not know that they mean the same thing. JRSpriggs 06:58, 15 August 2006 (UTC)
Of course. I will leave it in the main article on the weak force as well as anywhere else where discussion of the historical name is appropriate.
Ok, hearing no dissent, I will start doing this. Strait 15:45, 16 August 2006 (UTC)
No dissent, but please realize that some of us project regulars might not read this page daily, or even weekly. Also, please do be sensitive to historical usage and history. While learning physics in grad school, history may seem utterly unimportant in comparison to the difficulty of mastering the material. When one is older, the history becomes much more interesting, as one learns about who thought what about what, when. Sometimes, the crazier formulas (and names of things) start making sense when placed in proper historical context. linas 04:16, 17 August 2006 (UTC)
Of course. I wouldn't advocate renaming "Compton scattering" to "electron photon scattering." But I don't think any historical interest is lost in this case while I think that a significant amount of clarity is gained. I guess you agree (at least enough not to object).
I will wait longer than 36 hours in the future if I have some similar question, but I won't wait several weeks unless there is an obvious consensus that that is appropriate. What do you think an appropriate wait time is? --Strait 04:29, 17 August 2006 (UTC)

Well, its been a week since I last visited this page so ...

But the question is strange. If some edit is a good idea, it should be done. If its a bad idea, you'll find yourself in an edit war before long. Changes should be menitioned on this talk page if you have reason to beleive tht an edit war may develop, or if the discussion has already factionalized, in which case it won't matter much if you wait or not. linas 23:57, 24 August 2006 (UTC)

## Physics-stubs oversized again

I note the Category:physics stubs are up to five pages again; I've crunched some numbers based on perm-cat membership, and I don't see any obvious holes in the stub type coverage, though Category:Mathematical physics stubs (205), Category:Atomic, molecular, and optical physics stubs (82) and Category:Astrophysics stubs (80) might be viable, depending how riddled those counts are with false positives. Mainly I suspect there's a large amount of under-sorting to existing stub-types. Certainly I note over 100 in each of Category:Relativity, Category:Particle physics, Category:Quantum mechanics, Category:Thermodynamics and Category:Classical mechanics -- lists available on request, if someone with expert knowledge would be good enough to sift wheat from chaff. Alai 00:24, 17 August 2006 (UTC)

I think a change in the stub sub-categories could help: I dislike the 'Nuclear and Atomic physics' category nuclear-stub. Wouldn't make sense to make it solely 'nuclear' and make an 'Atomic, molecular, and optical physics' sub-category? This is how most physics sub-departments are broken up. There are many articles that are 'physics stubs' that I would move to a AMO sub-category but currently can't get moved because they fall in both optics and nuclear/atomic (unless we just put them in both).Waxigloo 20:42, 26 August 2006 (UTC)
Sounds sensible; hopefully it won't deplete the nuclear-stub type too seriously. I just realized we don't actually have a thermodynamics-stub, so I've proposed both of these here. Please add any comments there. In the meantime, if anyone would be inclined to volunteer to double-check lists of potential re-sortees to the existing stub types, I could opload these, and if they're OK, restub them by bot. Alai 09:09, 13 September 2006 (UTC)

## Meaning of QED

Should QED be:

1. a page about the phrase quod erat demonstrandum, with a dablink to QED (disambiguation),
2. a page about quantum electrodynamics, with a dablink to QED (disambiguation), or
3. a disambiguation page, with links to both the above and to lesser uses.

My opinion is clearly (3), but come share yours at talk:QED (disambiguation). --Trovatore 20:40, 17 August 2006 (UTC)

## Wikiversity Physics school

I cordially invite the participants of this project to the newly founded wikiversity school of Physics. It's still being moved over, so a lot of work is still needed--Rayc 23:45, 17 August 2006 (UTC)

## Plasma (physics): Wikipedia:Peer review

I've requested Peer Review for the Plasma physics artcles, discussion should appear on the page at Wikipedia:Peer review/Plasma (physics)/archive1. All comments welcome. --Iantresman 11:12, 18 August 2006 (UTC)

## Sanity check - is this diagram inaccurate?

Wrong?

"There is a serious mistake in this picture. The force on the left of the pulley, represented by the red arrow, is not directed vertically. Therefore this force has a vertical and a horizontal component in a cartesian system and will pull the pulley to the left: not a static but a dynamic situation. To keep a long story short: the picture will be correct when the cable (and with it the red arrow) on the left of the pulley is vertical and parallel to the cable on the right side of the pulley. (Only then will the forces be in balance.)"

Is this true? If so, does anyone feel like uploading a corrected version over the top of this one? :) If not, would you mind explaining why at the Commons Help desk/here? Thanks! --pfctdayelise (translate?) 13:58, 18 August 2006 (UTC)

The objections are correct. I can't make a picture that's anywhere near as pretty as this one is, though, so I'm not the person to ask to fix it. A suitable replacement would either have both cables vertical, or both cables at an angle. The sum of the force vectors should be zero, representing a motionless situation; otherwise the reader will likely get confused. --Christopher Thomas 14:35, 18 August 2006 (UTC)
Agreed. Besselfunctions 22:14, 18 August 2006 (UTC)
Or the pulley could have friction and the numbers would change. Usually not the problem you want to illustrate though. — Laura Scudder 03:38, 19 August 2006 (UTC)
Disagree. It depends what the picture is being used for. If you go the page of pulley pictures [4], it is labelled as 'moveable pulley'. Comparing it with the fixed pulley next to it, I would say this image was created to be dynamic on purpose. If this picture is being used somewhere in a different context then that is the text's problem not the images.Waxigloo 17:59, 19 August 2006 (UTC)
I disagree with the disagreement. The pulley is intended to be movable (i.e., in a non-fixed position), but the force diagram is still incorrect, as it shows an unbalanced force on the pulley. This picture shows the problem even more clearly: The vectors are unbalanced at a pulley that's at a fixed pivot point. You could make the argument that there are additional force vectors not shown (lateral forces at the anchor point), or that the angles of the ropes are exaggerated for emphasis, but an explicit disclaimer to this effect should be added if so, and diagrams that don't have this problem would be preferable. --Christopher Thomas 19:34, 19 August 2006 (UTC)
I agree the diagram is inaccurate. The horizontal force must be balanced. It would pull the rope from vertical to an angle sufficient to balance horizontal forces. This would be a GREAT illustration of the importance of a correct free body diagram for our Wikiversity statics lesson soon to be arriving here. [5] I will try get permission from the author to use it as an example of how easy it is to mislead yourself at the start of simple appearing problems. The second picture will be a good statics problem! I just need to delete the 50N rope tension and insert T. At least it is visually correct (since the anchor can balance the rope on the left x component) with just incorrect tension for the Weight shown. user:mirwin

Well, its not even visually correct! The horizontal component of the force isn't balanced! Either both ropes are vertical, or neither rope is vertical. The angle of both ropes to the pulley should be equal and opposite. Beautiful isllustration, but totally wrong. linas 00:04, 25 August 2006 (UTC)

Much better.
Could someone please FIX IT???? :( --pfctdayelise (translate?) 03:22, 25 August 2006 (UTC)
Contact the editors who originally contributed those images. You really don't want an Xfig version from me. --Christopher Thomas 03:29, 25 August 2006 (UTC)
Fixed it. --JohJak2 18:04, 14 September 2006 (UTC)

## Eigenvalue, eigenvector and eigenspace

Eigenvalue, eigenvector and eigenspace is up for a featured article review. Detailed concerns may be found here. Please leave your comments and help us address and maintain this article's featured quality. Sandy 22:08, 18 August 2006 (UTC)

## Two small items

### Wikipedia:Requests for comment/Rod Ball

I filed a user conduct RfC concerning User:Rod Ball. If you are interested in SR and pointless disputes (respectively attempts to end them), you may want to have a look. Or better yet, have a look at Bell's spaceship paradox (and perhaps at Ehrenfest paradox). And don't hesitate to criticize me if you judge, that I'm somewhat acting out of proportion. --Pjacobi 11:39, 21 August 2006 (UTC)

### Steorn

If anyone is interested to watch the newest Perpetuum Mobile scam, pls put Steorn on your watchlist. I tried to get this deleted, but a overwhelming number of keepers resulted in speedy keep. --Pjacobi 11:39, 21 August 2006 (UTC)

I have recently expanded the neutrino oscillation article quite a bit. Since I have made essentially all of the edits since early July, I would appreciate having some people look it over for any combination of spelling, grammar, style and/or physics content. I've probably made errors that I can't see because I've looked at them for too long. Thanks! --Strait 20:58, 21 August 2006 (UTC)

## "Homeopathy relativity"

Say that with a straight face! Better yet, vote on the AfD. Anville 19:43, 22 August 2006 (UTC) Home page: Homeopathy and relativity So far nobody is "enjoying" this discussion.

## Another apparent spammer.

69.254.131.188 (talkcontribs) is inserting a substantial number of links to books by a "Stanley Humphries", and to various software projects hosted at http://www.fieldp.com. The software is claimed to be free software, but this is alleged not to be the case in edit comments in some of the affected articles. Smells of self-promotion either way.

I'm too tired to deal with another spammer this week. Someone else can do the carrot-and-stick dance for this one (or punt it to AN/I). It could be that this person honestly doesn't know this is wrong. --Christopher Thomas 03:11, 23 August 2006 (UTC)

Cleaned up. Maybe or maybe not related to ChrisSmol (talk · contribs); bolded '''some software''' headings and software links from both. Femto 12:41, 23 August 2006 (UTC)
In the spirit of my remark that "digs" are as likely to exonerate as convict, I note that our anon's IP comes back to Comcast in Albuquerque, which is consistent with his claim to be Stanley Humphries, who is allegedly associated with a company called Field Precision in Albuquerque, NM, and who is apparently indeed the author of the website he is linking to, as he implies in this edit. Furthermore, a quick check of the UW library catalog shows these books:
Humphries, Stanley, Jr. (1990). Charged particle beams. New York: Wiley. ISBN 0-471-60014-8.
Humphries, Stanley, Jr. (1986). Principles of charged particle acceleration. New York: Wiley. ISBN 0-471-87878-2.
So, while I haven't tried to check his edits for questionable claims, much less check these books for questionable claims, it seems fairly likely that Humphreys really is an expert, in the usual scholarly sense, on precisely what he claims to be an expert on. I don't know why he currently lacks an academic affiliation, but he might have retired or have spent his career in industry. If only there were a physics/engineering analog of Math Geneology, we could probably verify his academic as well.
In sum, this might be something of a false positive in our spam control efforts. If possible, Humphreys should be urged to create a transparent user account and tell the world more about himself to prevent this kind of misunderstanding.---CH 08:15, 29 August 2006 (UTC)
Oh, rats, CT is probably right about the real issue here, namely vanispamcruftvertisement. Despite Humphrey's muddled protestation about freeware, the first link I checked went to Gambet which says in a box at left "Check prices and ordering information: www.fieldp.com/order.html". Sigh... is it any wonder that I am such a pessimist about the human species? I don't see much evidence of any connection with ChrisSmol (talk · contribs), though.---CH 08:24, 29 August 2006 (UTC)

## Request for help on Photon

Hi all,

I've devoted some time recently to Photon, which now seems to be a "B-class" article. I'd like to take the article higher, though, maybe even to Good Article status, but I don't have much experience with what's required. Could some experienced people here please look the article over and give suggestions for further improvements? Thanks muchly! :D Willow 15:50, 23 August 2006 (UTC)

## Indices on Christoffel symbols

A recent edit to Christoffel symbols replaced ${\displaystyle \Gamma ^{m}{}_{i\ell }\,}$ with ${\displaystyle \Gamma _{i\ell }^{m}\,}$ throughout the article. I seem to remember that there is actually a reason for the staggered indices, but it was some time ago that I looked into this and I never got it properly. Could somebody in the know please check, and if necessary revert while explaining the matter on the talk page? Cheers, Jitse Niesen (talk) 15:07, 25 August 2006 (UTC)

The ordering is important to the indices. So in a way the staggering is a way of remembering that
${\displaystyle g^{i\mu }g^{\ell \nu }\Gamma _{i\ell }^{m}=\Gamma ^{m\mu \nu }\neq \Gamma ^{\mu \nu m}}$
There's probably a more fundamental way to say that, but we're delving into some old material here for me. — Laura Scudder 15:45, 25 August 2006 (UTC)
I agree that the changes Jitse noted should be reverted. ---CH 22:07, 25 August 2006 (UTC)

In most GR texts there is no space. The Christoffel symbol with all indices downstairs is defined by contracting with the metric tensor. You can avoid giving that definition by showing the space. But I think it is still necessary to write that in many books the symbol is written without the space and that it is the same as given in the article. Count Iblis 23:30, 25 August 2006 (UTC)

I have seen it both ways and I do not see the advantage of the longer form. There is no issue of ordering because the contravariant (upper) index is distinguished by the fact that it is upper rather than lower. I have never seen a Christoffel symbol with two or three upper indices. The only choice is one upper and two lower or all three lower. In the latter case, the first (leftmost) lower index corresponds to the upper index in the other case. Where is the problem? JRSpriggs 08:41, 26 August 2006 (UTC)
Well, it's just that one needs to define the symbol with all three indices downstairs by declaring that the upper index becomes the leftmost index when brought downstairs. That's not a problem, but one can avoid even mentioning this by indicating the space. Count Iblis 12:38, 26 August 2006 (UTC)

## Wikipedia:Requests for comment/Rod Ball

Unless there has been some change of official policy of which I am unaware (in which case please let me know forthwith), it is not improper for me to ask for comments from members of this WikiProject in the above RfC. I feel that in the edit quoted in my "view" in this RfC, Rod Ball (talk · contribs) has outrageously mispresented my knowledge, my reading, my actions, and what I told him concerning my knowledge, my reading, and my actions. I regard his outrageous misrepresentations of what I have done and said here as a violation of WP:NPA-WP:CIV-WP:VER and I don't know what else. While the unfairness and completely counterfactual character of the quoted statement by Rod Ball is verifiable (given sufficient effort) by any Wikipedia user, my statements about the very extensive literature on the Ehrenfest and Bell paradoxes would no doubt benefit from endorsement by knowledgeable physicists. Note that the excellent review paper by Grøn is available on-line and contains hundreds of references; see the citation to the book edited by Rizzi and Ruggiero which appears at the end of Ehrenfest paradox.---CH 22:07, 25 August 2006 (UTC)

## More problems at black hole

Latest shennanigans at black hole: Danras (talkcontribs) repeatedly inserting his own arguments for why escape from black holes is possible. More help with cleanup would be handy. --Christopher Thomas 04:08, 26 August 2006 (UTC)

The author of symmetrical relativity returns. Oh boy. Anville 16:03, 26 August 2006 (UTC)
Watch for unusual editing from Quasarq (talk · contribs) as well. linas 20:49, 28 August 2006 (UTC)
My brain hurts just looking at that contribution history. Probable meatpuppet: Liseusa (talkcontribs). Seems to be inactive. Possible collaborator: Homy (talkcontribs), though that user seems to almost completely deal with things homeopathy-related. --Christopher Thomas 21:27, 28 August 2006 (UTC)
At a glance, I agree, looks to me like Liseusa (talk · contribs) is a candidate for identification with the author of the article deleted via symmetrical relativity. I just posted to Talk:Black hole some comments on this edit, but I really hope you don't need me to know that this edit is utter Dreck from start to finish. ---CH 06:03, 29 August 2006 (UTC)
That didn't come out right. I was trying to say that I was dismayed to see this fabulously bad edit by Danras went unreverted for 75 minutes. How could that have happened?---CH 08:28, 29 August 2006 (UTC)

## Weight, mass and weighing scales

Various articles claim that, whereas spring scales measure weight, balances measure mass directly:

Weight: A spring scale or hydraulic or pneumatic scale measures the weight force (strictly the apparent weight force) directly. [...] Mass may be measured with a balance, which compares the item in question to others of known mass.
Weighing scale: A balance (also balance scale, beam balance or laboratory balance) is used to measure the mass of an object. [...] While the word "weigh" or "weight" is often used, any balance scale measures mass, which is independent of the force of gravity.

I think this is wrong. If true, it would mean we could use a balance to measure the (positive) mass of a buoyant helium balloon. That the present text is misleading is evidenced by this recent contribution to a discussion at the Science reference desk: [6]. The issue is that a spring scale measures the apparent weight of an object in absolute terms, while a balance compares it to the apparent weight of a reference object. The effects of variations in gravity and (spatially uniform) acceleration are thereby cancelled out. The effect of buoyancy is not (unless the reference object happens to have the same volume). As the balloon counterexample shows, the effect can be very large, and even for much denser objects the effect must be taken into account for high-precision measurement.

How can we best fix this? I don't want to make something already complicated and possibly confusing even more so, but we should also not let incorrect things stand. --LambiamTalk 20:52, 27 August 2006 (UTC)

I'm having trouble seeing the problem. In a uniform gravitational field in vacuum, the relative weights and the relative masses of two objects are the same. Buoyancy (lack of vacuum) fouls measurements of weight _and_ mass, at least as far as I've understood the term "weight". A boat floating on water is generally not described as "weightless". --Christopher Thomas 21:28, 27 August 2006 (UTC)
Take the average kitchen scales. Weigh a stone on it. Now repeat the experiment in a zero or low gravitational field. It will not be the same (in the absence of gravitation, and any prior force, the mass will just sit still in 3D space rather than going down onto the scales). Hence weighing scales measure the weight, not the mass.
Now take a balance. (Note: balance, not weighing scales. The latter part of the above statement applies just to the section on balances, I believe) Both sides will act as above. In the absence of gravitation completely, nothing will happen. Add a uniform gravitational force, no matter how small, and the balance will work (albiet slowly, dependent on the strength of the gravitational field). It's still reliant on weight, though.
Conclusion: the sentence is wrong, and needs to be rewritten. Mike Peel 21:59, 27 August 2006 (UTC)
I am quite familiar with the difference between "weight" and "mass", thank you. Note the word "relative" in my response. The ratio between the weights of two objects and the ratio between the masses of two objects should be the same under any reasonable lab-bench conditions. Thus, the statement that the balance, given a reference mass, can measure the mass of an object is correct as far as I can tell. --Christopher Thomas 00:54, 28 August 2006 (UTC)
Sorry - I was very tired when I wrote that, evidently too tired to completely digest the exact grammar of the article's sentence. When you read ", which" as "and", my comment above would have pointed out that the balancing scales weren't completely independent of gravity - otherwise you could remove it completely with no problem - and hence that there was another problem with the article. When you read it correctly, the article is correct as-is (that mass is independent of gravity). Oops. Mike Peel 08:15, 28 August 2006 (UTC)
But the point was not (in)dependence of gravity, but whether a balance measures mass. Does a balance measure the mass of a balloon (which we all agree is independent of gravity)? Do humans in balance on a very sensitive balance tip the scales to the other side when they exhale, and thereby reduce their mass ever so slightly? That is what the article would make you believe. --LambiamTalk 08:53, 28 August 2006 (UTC)

The equivalence principle assures us that weight will always be proportional to mass. So in a gravitational field, as we have on Earth, measuring them is equivalent. The helium balloon is a red herring, one always has to make sure that the measurement is done under appropriately controlled conditions. For example, no one should have his finger pressed on the scale or balance. Similarly, the measurement should be done in a vacuum, so that the atmosphere does not have its finger on the scale or balance. The interesting question is how one should measure mass when your laboratory is in free fall. Either instrument could be used, if you put them in a centrifuge. But the balance requires standardized masses to compare with. Whereas the scale requires a standardized spring with calibrated markings and the centrifuge would have to be standardized also. JRSpriggs 05:56, 28 August 2006 (UTC)

Allow me to point out that the articles in question do not contain any reference to "vacuum". In most cases when balances are used to weigh an object, the measurement is in fact not carried out in a vacuum. My estimate is that this is true for more than 99.9% of the cases. In large parts of the world, new-born babies are still weighed on balances. The hospitals do not have the equipment to generate a vacuum in a space large enough to contain the baby. Of course everything has to be carried out under the proper conditions. But is the interested reader who wants to know something about weighing scales supposed to know in advance what the Wikipedia editors have deemed "the proper conditions" to be? The article as it stands is true and not misleading provided it is accompanied by a physicist who explains how you are supposed to interpret the text. --LambiamTalk 06:37, 28 August 2006 (UTC)

Babies are about 1000 times denser than air. This makes the deviation from a vacuum-based measurement about 0.1%, which is small enough to neglect. "Appropriate conditions" are conditions in which errors are small enough to be disregarded. Virtually all uses of balances that I'm aware of fall into this category. --Christopher Thomas 07:14, 28 August 2006 (UTC)

But do you feel that it is reasonable to assume that the reader knows in advance that the learned editors of these articles have decided that weighing in air is appropriate for babies, but inappropriate for balloons, which must be weighed in vacuo? Also, uranium is about 20 times as dense as babies, but a 0.005% error in weighing uranium might nevertheless be unacceptable. --LambiamTalk 07:24, 28 August 2006 (UTC)

To answer your question directly, yes, I feel that it is reasonable. Per comments on the other page, a sentence fragment indicating that mass "of objects much denser than air" is measured should be more than sufficient as a caveat if you feel one is needed. Any precision weight measurements 1) are typically performed in vacuum and 2) have a myriad of other sources of error beyond buoyancy that have to be taken into account, so I don't think any additional caveats are needed. --Christopher Thomas 16:50, 28 August 2006 (UTC)

So what's the conclusion? Is there consensus? Seems to me the original wording was correct -- balances measure mass, springs measure weight, and there are a myriad of sources for measurement error, including bouyancy, air turbulence (wind), friction, settling dust, calibration problems, uncentered balance, Earth's magnetic field acting on iron components in the balance, magnetic fields due to nearby electrical wiring, chemcal reactivity between air and the substance wieghed (or the balance itself), condensation of atmospheric water on cold items, evaporation of water from wet items, convection of air from hot items, electrostatic fields from feet shuffled on carpets, Coriolis force, gravitational anomolies (i.e. using balances near a mountain), seismic activity, including big trucks rmbling down the street, thermal expansion/contraction of components of the balance. What else. Are all of these mentioned in te articles? linas 21:07, 28 August 2006 (UTC)

## Help on redshift

A person from FAC thinks that many common-knowledge facts described in exposition on redshift need to be referenced. I'm not at all convinced of this, but I'd like a second opinion. If someone wants to go through and add references or remove {{fact}} tags to the article, that would be appreciated. --ScienceApologist 01:32, 28 August 2006 (UTC)

The relevant FAC page is here, for anyone wanting to participate in the discussion.
I think the objections are unreasonable, but that it would probably be easier to dig up a pile of unneeded citations than to talk sense into the user objecting. Everything prior to the "observations" section could be handled by citing one well-chosen astrophysics book. The "observations" section looks like it would require spending a couple of hours in an astrophysics papers database. I'm afraid I don't have access to either item. --Christopher Thomas 01:46, 28 August 2006 (UTC)

## Citation templates

Hi all, please use these wherever possible. In particular, when citing an on-line article, please note that very few Wikipedia readers have an academic appointment and are using their office computer to access a journal's website, whereas anyone can download an arXiv eprint for free, so

1. in the case of published papers which are on-line, please use a link to the arXiv abstract page (not everyone prefers to download a pdf!; postscript is much faster for those with a postscript printer!) rather than a link to the journal website,
2. in the case of eprints, please use the arXiv citation template.

Here is the tutorial (created for the defuct WikiProject GTR, hence the gtr-related examples):

• Book:

*{{cite book | author=Misner, Charles; Thorne, Kip S.; and Wheeler, John Archibald | title=Gravitation | location=San Francisco | publisher= W. H. Freeman | year=1973 | id=ISBN 0-7167-0344-0}}

• Article in a research journal:

*{{cite journal | author=Kerr, R. P. | title=Gravitational field of a spinning mass as an example of algebraically special metrics | journal=Phys. Rev. Lett. | year=1963 | volume=11 | pages=237}}

• Article in a research journal which was previously an arXiv eprint (check the arXiv abstract page to see if any publication details are noted):

*{{cite journal | author=Bicak, Jiri | title=Selected exact solutions of Einstein's field equations: their role in general relativity and astrophysics | journal=Lect. Notes Phys. | year=2000 | volume=540 | pages=1-126}} [http://www.arxiv.org/abs/gr-qc/0004016 gr-qc/0004016]

• arXiv eprint (not yet published):

*{{cite arXiv | author=Roberts, M. D. | title=Spacetime Exterior to a Star: Against Asymptotic Flatness | year = 1998 | version=May 16, 2002 | eprint=qr-qc/9811093}}

• Article in a book:

*{{cite conference | author=Ehlers, Jürgen; & Kundt, Wolfgang | title=Exact solutions of the gravitational field equations | booktitle=Gravitation: an Introduction to Current Research | year=1962 | pages=49–101}} See ''section 2-5.''

• Biography in the MacTutor archive:

{{MacTutor Biography |id=Friedmann|title=Aleksandr Aleksandrovich Friedmann}}

• Article at the Living Reviews website:

*{{cite web | author=Gönner, Hubert F. M. | title=On the History of Unified Field Theories | work=Living Reviews in Relativity | url=http://relativity.livingreviews.org/open?pubNo=lrr-2004-2 | accessdate=2005-08-10 }}

These have the following effects:

Maybe some kind project member can move this tutorial to the appropriate project page? And what about a page called something like "introduction for project newbies" which helps newcomers to editing physics-related articles find valuable resources like this tutorial? TIA! ---CH 19:24, 28 August 2006 (UTC)

IMO, the cite journal one would be better if it read:
*{{cite journal | last=Bicak | first=Jiri | title=Selected exact solutions of Einstein's field equations: their role in general relativity and astrophysics | journal=Lect. Notes Phys. | year=2000 | volume=540 | pages=1—126 | arxiv=gr-qc/0004016 }}
which comes out as:
• Bicak, Jiri (2000). "Selected exact solutions of Einstein's field equations: their role in general relativity and astrophysics". Lect. Notes Phys. 540: 1—126. arXiv:.
It woud also be useful if, for astronomy journal papers, people search the NASA ADS system and add links to the appropriate citation, as they have freely available copies of the journal articles available. Mike Peel 19:35, 28 August 2006 (UTC)

Done. ---CH 05:20, 29 August 2006 (UTC)

## Ballotechnics

While there's (finally) some movement to sanify Ballotechnics  (now ), which includes giving it a title that more accurately reflects its subject (nuclear isomer weapons), the editor coordinating the change and I are disagreeing over the degree to which Prof. Collins' hafnium bomb claims are taken seriously by the scientific community. If a few of the regulars could review the statements made on the talk page, and recent changes (both ways) at the article, that would be appreciated. --Christopher Thomas 15:40, 30 August 2006 (UTC)

I've just made the move, and I am cleaning up links now (that's how I got here). Working on a real ballotechnics insert shortly. In the meantime I'm with you on the Collin's issue, for what that's worth. Maury 16:46, 30 August 2006 (UTC)
The user making the disputed edits is now summarily dismissing my concerns. More eyes would be greatly appreciated. --Christopher Thomas 00:58, 31 August 2006 (UTC)
After discussion and lots of editing, the article on IGE appears to be comprehensible and accurate. I believe (correct me if I'm wrong), there's little or nothing to dispute there now, right? linas 21:02, 3 September 2006 (UTC)

## Update on Photon

Astrobayes has begun to scientifically peer-review the Photon article, with the goal of bringing it to Featured Article status. Your comments could help us get there! Please give us your assessment of the completeness, correctness, readability, etc. Also, there's been some debate as to whether the virtual photons used in summing probability amplitudes in quantum electrodynamics have three polarizations (as befits a particle of spin 1) or four (corresponding to the four components of the electromagnetic four-potential ${\displaystyle A^{\mu }}$). We all know that real photons have two transverse polarizations. If you know the answer and can cite scientific references, please let us know at Talk:Photon — thanks! Willow 11:06, 31 August 2006 (UTC)

Astrobayes has finished an excellent scientific peer-review of the Photon article. But you too can contribute to making Photon into a Featured article by adding your suggestions and comments at Talk:Photon! :) Willow 22:26, 1 September 2006 (UTC)