Wikipedia talk:WikiProject Physics/Archive 13

message: Wikipedia:Articles for deletion/Electric universe (concept). Comment as you will. --ScienceApologist 13:51, 1 January 2007 (UTC)
thread_title: Of possible interest

message: Wikipedia:Articles_for_deletion/Harold_Aspden. Comment please. --ScienceApologist 00:20, 2 January 2007 (UTC)
thread_title: another AfD

message: While on New Page Patrol, I ran across the following page, which you may be able to assist: Pasotron. TonyTheTiger 16:58, 3 January 2007 (UTC)
replies: text: At least this topic appears to be real.  I added a little bit with a few external hyperlinks, but it could be expanded much more.  Anville 19:36, 4 January 2007 (UTC)
thread_title:  Pasotron 

message: Comment here: Wikipedia:Articles for deletion/Ralph Juergens. --ScienceApologist 19:03, 5 January 2007 (UTC)
thread_title: AfD of interest

message: Portal:Physics now has an anniversaries section; additions to this section would be welcome at Portal:Physics/Anniversaries. Mike Peel 20:28, 5 January 2007 (UTC)
thread_title:  Physics anniversaries wanted 

message: It can be found here. The voting page is here. I haven't seen anything change there for weeks. What happens next?--Filll 21:35, 8 January 2007 (UTC)
replies: text: It has been the busy festive period, so I have left it lie over christmas.  I will have a form up on the situation at the weekend. SFC9394 21:45, 8 January 2007 (UTC)
thread_title: The WIP project to rewrite the [[physics]] lead

message: So far I've found four laws by Wien:
*Wien's Distribution Law
*Wien's Radiation Law
*Wien's displacement law
*Wien-Planck law
Is this true?  How many laws does he have?  Anyone know?  Also, the top two need to go to lower case and someone who knows these topics well should add the Wien-Planck law to Wikipedia. --Sadi Carnot 02:25, 8 January 2007 (UTC)
replies: text: Wien's displacement law describes the relation between blackbody temperature and the peak wavelength of the thermal emission.  This article is OK.  However, both Wien's Distribution Law and Wien's Radiation Law appear to describw the short-wavelength approximation of the blackbody function that is sometimes called "Wien's law".  The two articles should probably be merged, although neither article contains much to merge and Wien's Radiation Law is written much more clearly than Wien's Distribution Law.  Would people object if I did this?  I have my copy of Rybicki and Lightman right at hand.  Dr. Submillimeter 09:52, 8 January 2007 (UTC)
replies: text: Whatever one you do a merge on, the main one, in Wikipedia, should describe the one that Planck is referring to in is 1900 paper.  That’s the one I’ve been searching for. --Sadi Carnot 17:22, 8 January 2007 (UTC)
replies: text: That link refers to a "Wien's displacement law" and a "Wien's energy distribution law".  Which would you like?  Would it be OK if I just use what is written in Rybicki and Lightman?  Dr. Submillimeter 18:02, 8 January 2007 (UTC)
replies: text: Whatever is in Rybicki and Lightman sounds like a plan, just be sure to source it so that we all have a good reference to consult.  I'm guessing the main one should be the "energy distribution law"?  Thanks: --Sadi Carnot 02:51, 9 January 2007 (UTC)

text: Wien-Planck law is now a redirect to the Planck law article.  I will try to find a suitable name (i.e. a good name that is given in a textbook) for Wien's Distribution Law and Wien's Radiation Law before merging the two.  Dr. Submillimeter 09:46, 10 January 2007 (UTC)
replies: text: The section of the Planck law article on "The use of Stirling's formula" seems exceedingly weird to me.  The Stirling approximation (for n factorial) isn't even used in the derivation in the article.  Is this section a historical relic from some earlier editing?  And what the heck is all that stuff about a "monster"?  I haven't read through it at all thoroughly but it seems like a total non sequitur.  HEL 20:07, 10 January 2007 (UTC)
replies: text: Aha, I see it is being discussed further down this page.  Good.  HEL 20:17, 10 January 2007 (UTC)
thread_title: How many laws does Wein have?

message: May be of interest to people watching WPP -- WP:SCI, the work of a couple of editors to clearly delineate what should and should not be covered by WP. Sdedeo (tips) 20:29, 4 January 2007 (UTC)
replies: text: Don't forget WP:FRINGE, which covers some of the same territory but is a little broader in scope.  Anville 14:05, 5 January 2007 (UTC)
replies: text: Good stuff here. The regulars/old-timers should definitely take a look. linas 04:33, 13 January 2007 (UTC)
thread_title: Notability (science) criteria

message: The last edit at Parity (physics) says "It is important that the determinant of the P matrix be -1, which does not happen for 180 degree rotation in 2-D. Here a parity transformation flips the sign of either one of x or y, not both.". This changes the article's position on Parity in 2-D. So my question is what is essential to the definition of Parity? Is the negative determinate a necessity or is it an accident due to our living in an odd-dimensional space? JRSpriggs 06:04, 12 January 2007 (UTC)
replies: text: Parity is the transformation xi goes to -xi for each coordinate. So the sign of the determinant is negative in odd dimensions and positive in even dimensions. -Joshua Davis 06:27, 12 January 2007 (UTC)
replies: text: If you are sure, then please revert the change in the article. JRSpriggs 08:57, 12 January 2007 (UTC)
replies: text: Uhh, that  sounds wrong. Parity is the operator that takes you between the (two) disconnected components of a (rotation) group. Since rotations always have determinant +1, the parity operator must have determinant -1. The original edit sounds like it was correct.  linas 15:14, 12 January 2007 (UTC)
replies: text:  Linas, I stand corrected. On further thought, parity flips only an odd number of spatial directions and so has determinant -1. The equivalent group theoretic definition is rather nice. -Joshua Davis 17:12, 12 January 2007 (UTC)
thread_title:  What is Parity really about? 

message: FYI, since the article falls under your project, the Feb 2007 issue of Scientific American on page 24 has a one page article discussing Causal dynamic triangulation.  Since the CDT article is currently just a stub, I thought someone here might be interested in expanding it using some of the information from the magazine.  The article contained some less formal but still useful information comparing CDT to string theory and loop quantum gravity, as well as where research efforts currently lie. Dugwiki 20:22, 12 January 2007 (UTC)
thread_title:  [[Causal dynamic triangulation]] article in [[Scientific American]] 

message: Please take a look at plasma cosmology which has been newly revamped. Reference it, edit it, comment on it, etc. Thanks! --ScienceApologist 01:04, 13 January 2007 (UTC)
thread_title: Plasma cosmology live!

message: While trying to sort through laws named after Wien in response to comments made by Sadi Carnot earlier on this talk page, I encountered a few problems related to naming.  I would like some feedback on names before proceeding.
First, Wien has two laws that he is known for.  The first, Wien's displacement law, has been given a name that is used everywhere.  The function describes the peak wavelength or frequency at which light is emitted from a blackbody of a given temperature.  That page and its name should be left alone.  
Wien's other law (copied from one of the two Wikipedia pages on the subject, to be verified using Rybicki and Lightman) is
:u_\nu = \frac{8 \pi h}{c^3} \nu ^3 e^{-\frac{h \nu}{kT}}      (Equation X)
where u_\nu is the energy density of a blackbody.  This function is a good approximation for the short-wavelength end of the blackbody function.  This function also does not have a good name.  Among other things, I have seen it referred to as:
*Wien's Law  (Rybicki and Lightman as well as a couple of other textbooks)
*Wien's tail of the blackbody function (or something similar from Chandrasekhar)
*Wien's Distribution Law (Wikipedia and a few other odd references)
*Wien's Radiation Law (Wikipedia mainly)
To add to the confusion, Wien's law redirects to Wien's displacement law, even though some textbooks use Wien's law to refer to Equation X up above.
So, my two questions are:
*What do we call Equation X?
*What do we do with Wien's law?  Should it be a redirect, a disambiguation page, or an article page?
Please give me feedback on this.  I have searched several statistical mechanics and radiative transfer books, and I have not found a good, consistently-used name for Equation X. Dr. Submillimeter 23:10, 12 January 2007 (UTC)
replies: text: Isn't equation X the Wien approximation (aka Wien limit to the blackbody? As opposed to the Rayleigh-Jeans approximation or the Rayleigh-Jeans limit? --ScienceApologist 01:04, 13 January 2007 (UTC)
replies: text: Google seems to confirm that  Wien's approximation or Wien limit are both very good names for eqn X. I believe Wein's law should be a disambiguation page. linas 05:30, 13 January 2007 (UTC)
replies: text: Agree: use Wien approximation as the name for the equation, with Wien's law as a disambig. --Sadi Carnot 14:54, 13 January 2007 (UTC)
thread_title:  Wien lawlessness 

message: Hello. I have put Florentin Smarandache on articles for deletion. See: Wikipedia:Articles for deletion/Florentin Smarandache. Please vote. Wile E. Heresiarch 06:19, 14 January 2007 (UTC)
thread_title:  [[Florentin Smarandache]] on afd 

message: For the moment at least, Newton's laws of motion has been granted semi-protection. This has quelled the flood of vandalism which was making it difficult to maintain the article. However, the lingering effects are still there. I invite you-all to look it over and try to perfect it now that it has become relatively safe to do so. JRSpriggs 11:38, 14 January 2007 (UTC)
thread_title:  "Newton's laws of motion" are now semi-protected 

message: has added templates to Basic introduction to the mathematics of curved spacetime and Mathematics of general relativity which indicate that the former is a non-technical introduction to the latter. However, if you look at them, you will see that the former has a larger proportion of equations (and not simple ones), than the latter. JRSpriggs 12:59, 14 January 2007 (UTC)
replies: text: Well then, this needs to be addressed I think.--Filll 13:38, 14 January 2007 (UTC)
replies: text: I will point out that they are simple equations. And equations does not necessarily equate to more complicated. It is good I think to indicate what is the more introductory material and what is the more advanced material in a somewhat uniform manner. I do agree that the wording of the introductory tags might be a bit off in this case.--Filll 13:44, 14 January 2007 (UTC)
thread_title:  A basic introduction to GTR which is anything but 

message: Does anyone here know about Misner space? There seems to be some debate over its definition, kind of important as it was linked to in the did you know section of yesterdays main page. --Salix alba (talk) 09:59, 18 January 2007 (UTC)
thread_title:  Misner space 

message: Made some comments for help about the energy article on the main page that might better have gone here. Feel free to move them if they offend. SBHarris 12:38, 19 January 2007 (UTC)
replies: text: "Energy It's a mess, trying to do too many things. One of the problems is the blasted Wikiproject science template. You wouldn't try to do this with momentum or mass or electricity. Needs major disambiguation, and roles in society even for the definable joule kind of science energy, need subarticles and drastic cutting. Finally, much inanity needs removal. Help." (Moved from main page; it's more appropriate here. Mike Peel 18:18, 19 January 2007 (UTC)
replies: text: Thanks. SBHarris 18:31, 19 January 2007 (UTC)
thread_title:  Energy 

message: Is a picture really necessary?  Or could it be written as (uudds)?  Thanks, CarpD 17:44, 20 January 2007 (UTC)
thread_title: [[Pentaquark]]

message: Please comment here: Talk:Bohr model#Intro image debate to help reach consensus as to what “Bohr’s atom model” actually looked like.  Thanks: --Sadi Carnot 07:31, 23 January 2007 (UTC)
replies: text: At the scale of those images, the nucleus would be a point. JRSpriggs 10:24, 24 January 2007 (UTC)
thread_title: Bohr model intro image debate help needed

message: Carl Sagan has been nominated for a featured article review. Articles are typically reviewed for two weeks. Please leave your comments and help us to return the article to featured quality. If concerns are not addressed during the review period, articles are moved onto the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Remove" the article from featured status. The instructions for the review process are here. Reviewers' concerns are here.
SandyGeorgia (Talk) 20:23, 23 January 2007 (UTC)
thread_title: Carl Sagan FAR

message: I just rearranged and added to the Angular velocity article. It is presently classified as start-class, but perhaps it warrants an upgrade. I am not very practiced in asessing article status, nor do I know the procedure for asking someone else to take a look. Can someone give me some pointers? Thanks - PAR 03:21, 22 January 2007 (UTC)
replies: text: Edit the template at the top of the talk page, and change "start" to "B" (or "A" if you think its that, etc.).linas 01:40, 25 January 2007 (UTC)
thread_title:  Assessing article status 

message: See Talk:Afshar experiment#Neutrality Discussion. Article is primarily edited by the professor who ran the eponymous experiment, and there is a lot of dispute going on regarding accusations of WP:OWN, contentious editing, etc. A lot of self-proclaimed scientists are throwing a LOT of words around on the talk page and it's getting increasingly hard to follow.-Dmz5*Edits**Talk* 03:16, 24 January 2007 (UTC)
replies: text: FWIW, I have found Prof. Afshar to be a reasonable and well-tempered personality. Unfortunately, his ideas attract negaitve attention. I've attempted to mediate in the past, with little success. Danko should be barred from the talk page; he is incompetent on this subject matter (his knowledge is at the level of freshman physics). I have found Micheal C. Price, an editor I otherwise respect, to have crossed the line, repeatedly, in being uncivil, and in repeatedly adding his own original research in attempting to debunk (incorrectly) the Afshar experiment. I'm sorry to say, he should also probably be banned from that article, at least temporarily. Although it is difficult to wade through the arguments, for the most part I think Afshar has acted with nobility, and is not the party at fault here. (Full disclosure: yes, I've got a doctorate in quantum, yes, my initial reaction, like the rest of the world, was to disparage the topic.  I've since warmed enough to it to realie that it should not  dismissed out-of-hand; the arguments are subtle, and my impression is that the WP nay-sayers don't have the background to appreciate the subtlties.)  linas 02:03, 25 January 2007 (UTC)
replies: text: As a completely uninvolved party, and with admittedly only half a semester of graduate-level quantum mechanics under my belt, I would be willing to mediate this dispute. I have come across the Afshar experiment only once before, in reference to Freeman Dyson's suggestion that the uncertainty principle would not hold for suitably large scales. I've read through the article and the related pages and have to say that a lot of the arguments seem to not be over the physics (except where some obvious errors are made by User:Danko) or the point-in-fact science of the work but rather the philosophical interpretations or original research connections. As with all quantum articles, normal "philosophy warnings" associated with quantum mechanics should be followed. I'll e-mail Ashfar and cross-post this suggestion at the article in question. --ScienceApologist 03:14, 25 January 2007 (UTC)
replies: text:  Dear ScienseApologist, please show a clear statement that is wrong. Since we defend opposing viewpoints with Linas, Afshar, etc, it is perfectly understandable that they think I am incompetent. Alas, there is growing number of physicists supporting my thesis, and before you characterize my work I recommend you to read my PhilSci paper. Danko Georgiev MD 06:01, 25 January 2007 (UTC)
thread_title:  Request for comment: [[Afshar experiment]] 

message: FYI. Wikipedia:Articles for deletion/List of physics formulae linas 05:34, 26 January 2007 (UTC)
thread_title:  AfD [[List of physics formulae]] 

message: The frame-dragging article has recently been subject to some highly POV editing between two competing points of view, with accusations of censorship and other name-calling in the other article text.  See, for example, recent edits by User:87.17.229.141, and various other Italian IP addresses beginning with 87, some of the most recent of which accuse other editors of censorship, with accusations that they are mentally ill (see this edit and this edit).  It has also grown a rather large bibliography, yet currently lacks any specific supporting citations or attributions for any of the controversial opinions in the article.
Since most of the content of this article seems to be the disputed content, I have now removed all the disputed content, reducing the article to a very brief but uncontentious stub. This article now needs to be rebuilt, with serious attention to WP:NPOV and WP:CITE, to bring it up to date with current scientific knowledge, explicitly mentioning which areas are the subject of current scientific controversy.  -- The Anome 12:27, 29 January 2007 (UTC)
replies: text: Since the above, I've done quite a lot of tidying, and tried to turn the bibliography into a proper list of references. I'd still appreciate any comments from other editors on the current version of the article. -- The Anome 13:49, 29 January 2007 (UTC)
thread_title:  [[Frame-dragging]] 

message: I've noticed that many articles here on wiki (e.g. the special relativity article) don't explain what's so problematic about faster than light signals correctly. Of course, it is trivial to note that in some frames the "cause" will happen later than the "effect". However, this in itself is not a problem, as is explained in this article on pages 10 to 13. It is the causal paradox you could get which is the problem.
The Scharnhorst effect cannot be used to create a causal paradox, so it is not a problem. The wiki article on this topic fails to mention this and the impression is left that the faster than c propagation of light in the Casimir vacuum could cause problems...  Count Iblis 14:02, 29 January 2007 (UTC)
thread_title:  Faster than light paradoxes