User talk:A. di M./Archive 1

Archive 1

Archive 2

Archive 3

Normalized frequency (digital signal processing)

This is an automated message from CorenSearchBot. I have performed a web search with the contents of Normalized frequency (digital signal processing), and it appears to be very similar to another wikipedia page: Normalized frequency. It is possible that you have accidentally duplicated contents, or made an error while creating the page— you might want to look at the pages and see if that is the case. If you are intentionally moving or duplicating content, please be sure you have followed the procedure at Wikipedia:Splitting by acknowledging the duplication of material in edit summary to preserve attribution history.

This message was placed automatically, and it is possible that the bot is confused and found similarity where none actually exists. If that is the case, you can remove the tag from the article and it would be appreciated if you could drop a note on the maintainer's talk page. CorenSearchBot (talk) 18:09, 1 February 2009 (UTC)

Margins

Hi. I like what you are doing with margins. When it is completed, I’ll be first in line to apply it to some values on Kilogram that {{Val}} choked on. Here’s a wish list:

1. That it handle scientific notation, whereby thinspaces are used on both sides of the multiply sign
2. That the entire expression nowrap
3. That typing a simple keyboard hyphen (-) for a minus sign be rendered with the true, longer-looking minus sign (−)
4. That any span gap following the numeral 1 be given a 0.2-em width.

Example: It would hopefully be able to accomplish all of this… {{nowrap|1=6.022<span style="margin-left:0.25em">141<span style="margin-left:0.2em">79(30)</span></span> × 10<sup>−23</sup> kg}} → 6.02214179(30) × 10⁻²³ kg

Here, for comparison, is the same thing as above, but with the standard keyboard-typed hyphen for a minus sign (too short): 6.02214179(30) × 10^-23 kg

Greg L (talk) 23:44, 6 February 2009 (UTC)

Point 2 was already handled. Now I've added support for point 1, too: {{User:A. di M./margins|6.022|141|79(30)|e=−23}} produces 6.02214179(30) × 10⁻²³. You still need to add the minus symbol by hand (not a great deal, I think, as there's a link to add one in the "Insert" box below the edit summary), as I would have no idea on how to turn the hyphen into a minus sign automatically. As for the spacing sizes, I wouldn't know how to make it depend on the previous character (nor see the point of it; why shouldn't all groups be spaced by the same amount?); also, personally I'd prefer to use 0.2em spacing everywhere, but it would look inconsistent in articles using both {{val}} and the new template. --A. di M. (talk) 00:08, 7 February 2009 (UTC)

• why shouldn't all groups be spaced by the same amount?: the 1 digit has extra space around it so 0.05 em less span gap looks better. As for 0.25 vs. 0.20, there are a bunch of tradeoffs. We discussed what various editors see here on MOSNUM and then went off-line to share e-mail screen shots of what everyone was looking at. Firefox resolves to 0.05-em increments. Safari does not. Safari rounds 0.05 increments down and tends to produce wider-looking gaps than Firefox. We even had an editor back then who owned an iPhone and looked at the results as we were tweaking the output.

  User:Army1987 is pretty good with templates. I bet he can make it so you can enter a hyphen for a negative exponent and have it substitute a true minus sign. Going down off the keyboard to the Insert pallet is something many editors are going to forget about. Greg L (talk) 00:25, 7 February 2009 (UTC)

← As for the spacing of 1, I guess it depends on the font? For example, the font my browser uses adds serifs to the digit 1 even if it's a sans-serif font, probably for that reason. Given that unequal spacing will look better when using some fonts and worse when using other fonts, I guess we'd better stick to the KISS principle? See the reasons why MediaWiki talk:Common.css#Proposal: shifting italics text slightly to the left was rejected, and also Template talk:Radic. --A. di M. (talk) 01:26, 7 February 2009 (UTC)

• Works for me. Getting a darn minus sign instead of the nearly invisible hyphen would probably be the biggest thing we can do for a consistent look (and readability). Maybe User:SkyLined can help on this since he tackled this issue once before??? Greg L (talk) 04:04, 7 February 2009 (UTC)

• • Taking a look into the implementation of {{val}}, it seems that it uses a math-based technique for making the hyphen into a minus. There should be no problem in doing that for the e parameter (I can't imagine it being used for anything other than a number), but I'm going to test what happens when it is used with words or other stuff, to decide whether it's safe to use it for the first argument too. --A. di M. (talk) 11:31, 7 February 2009 (UTC)

• • Indeed. I've implemented it for the exponent ({{User:A. di M./margins|6.022|141|79(30)|e=-23}} using a hyphen becomes 6.02214179(30) × 10⁻²³), but if I try to extend it to the first argument the template stops working when it is not a number, as in "P.A.M. Dirac". I'll point out this discussion to this SkyLined. A possible solution if all else fails could be to fork the template into a general-purpose one and one for numbers. --A. di M. (talk) 11:52, 7 February 2009 (UTC)

• I’m going to have MOSNUM revised with wording regarding {val} once the 2.0.1 bug fix is uploaded. The new verbiage will mention its 13 to 15-digit limitation and how one can use {margin} for values {val} chokes on. Can we mention {margin} now? Has it bet “released into the wild” yet? Greg L (talk) 00:15, 11 February 2009 (UTC)

• No, it's still hosted on a user subpage of mine, but I wouldn't object to it being copied to the template namespace. --A. di M. (talk) 00:18, 11 February 2009 (UTC)

• Putting it into template namespace is well out of my experience zone. I will propose wording for {val} that makes no mention of {margin} at this time. I trust that you will advise Masem (or some other admin) when {margin} is in template namespace and will also see to it that the couple areas where {val} is mentioned also mention {margin} as a work-around for 13+ digit numbers. Why “margin”? That name must make sense to programmer types but to someone like me, margins are the spaces at the left and right of a page. I would think something like {{numgap}} would be more intuitive to the creatures that will be using the thing. Greg L (talk) 04:00, 11 February 2009 (UTC)

Yes, I wasn't convinced of the name (that was one of the reasons I didn't create it in the template space in the first place). As for "numgap", well, the template needn't be only used for numbers ... but {{gap}} already exists. {{Gaps}} is free, though. Gonna move it there. --A. di M. (talk) 11:16, 11 February 2009 (UTC)

Done. See Template:gaps. --A. di M. (talk) 13:29, 11 February 2009 (UTC)

Manual of style comments on the date time template

Thank you for your care and thoroughness in consideration of my note. I made your recommended corrections and believe they make it more clear. I corrected the purple to green, and inserted the HST link. If there any other recommendations, please let me know, or feel free to correct them. I don't mind at all. Now to the meat. You have acute senses. Regarding this T00:00 nonsense. You didn't say it, so I did. It is quite simply nonsense. In my laziness, I did not notice that those examples were dated from an earlier version that did not yet support precision. If the user only specified the Year and month, only the year and month is emitted. Note that I always emit UTZ as the first parameter demands users be specific with time zones if they specify hours and minutes. That was a tactical decision, not anything driven by the template. It allows the contributor to vary the precision eg hours only, but these values are meaningless without timezone. First parameter is about "what the time is", the second is "how the contributor wants it to appear. Just the same as the semantics of the familiar [[precise article name|abbreviated form of name]] pattern. ISO date values can be verified in the Opera Browser or in articles that demo this template. Let me know if you are interested in verifying the microformats code emitted, and I will provide instructions and an example. Regards, -J JMesserly (talk) 16:25, 9 February 2009 (UTC)

Rather than deleting the article?

Sadly the history of the history of the article on quaternions is that some of the content consists of material that was simply copied and pasted out of other articles, in an attempt to make them more focused. In particular cutting material about people and places from the classical quaternions article makes that article a lot stronger.

I think that there needs to be an in depth article on the history of quaternions, but I have been focused on working on other material, maybe I can go back to this article and make a few improvements.

The cited material about the Fitzgerald transform represents some pretty intensive research work in particular. Perhaps a good place to start would be to provide a list of what you think are problems with the article?

Simply saying an article is nonsense is not really very specific.Hobojaks (talk) 21:22, 28 February 2009 (UTC)

Kilogram’s note #4

Perhaps you can check in here at Talk:Kilogram#Relativity_revisited and address any further concerns of Physchim62. Greg L (talk) 03:33, 16 March 2009 (UTC)

OK, I'll take a look at it... --A. di M. (talk) 15:17, 20 March 2009 (UTC)

Earthquake?

This morning, the AP had a front-page article about a 6.5 in Indonesia. Nothing about a 6.7 in Italy. What? You guys are chopped liver? Greg L (talk) 02:45, 6 April 2009 (UTC)

• Ah, here it is… 6.3 in Italy. I got the news from you before CNN. Greg L (talk) 03:11, 6 April 2009 (UTC)

Thanks for the concern. (And yes, most of us are chopped liver. Many people in L'Aquila ran away in panic from their houses last week after a 4.3 quake which did no more damage than a few tiles falling down from a moulding.) Thank God I didn't leave for L'Aquila yesterday... Fortunately all the few friends of mine who were there are fine. (Thank God it happened when many university students were at their parents' homes in their home town because of Easter holidays. Unfortunately there have been at least a dozen victims, may they rest in peace.) --A. di M. (formerly Army1987) — Deeds, not words. 05:59, 6 April 2009 (UTC)

I had guessed the meaning of "chopped liver" incorrectly (I thought it meant someone easily frightened). Anyway, it's hardly surprising that "Wikipedia is faster than CNN", given the disastrous state of mass media in Italy. I hastily turned on my laptop — I was going to leave for L'Aquila this morning, but if the epicentre is there and I felt it so badly here, L'Aquila must have been razed to the ground... But I could get no info other than that which my fellows could get from the website of the Italian institute of geophysics before it went down, and which they exchanged on Facebook: the first time I used Facebook for anything serious. ANSA gave no announcement until 5:14 and Mediaset didn't until 7:15. (According to the Italian institute of geophysics — now that their site is back, the tremor of 3:32 had a Richter magnitude of 5.8 and a moment magnitude of 6.2.[1] --A. di M. (formerly Army1987) — Deeds, not words. 08:38, 6 April 2009 (UTC)

• The news coverage today makes it clear that it was devastating to L'Aquila. No other words come to mind other than, “I am sorry for your sense of loss to your country and your grief for your fellow citizens.” Greg L (talk) 20:50, 6 April 2009 (UTC)

  P.S. I used the expression “chopped liver” knowing you might not recognize it, but with the expectation that you might appreciate learning a new American idiom. And, lest you think I was intentionally glib regarding an earthquake there, I made that post when the CNN news story was only eight minutes old and before they had expanded it with news of deaths. I am rather surprised at the extreme loss of life. The most recent earthquake in California (a 6.0 in Parkfield under wood-frame farm houses) caused almost no damage—and certainly no deaths. Masonry construction and earthquakes are clearly a nasty combination. Greg L (talk) 21:07, 6 April 2009 (UTC)

(edit conflict) Seeing streets I walked just three days ago covered in debris on TV is a very sad experience. Had this happened just 12 hours later (or, had I had lessions from 9:30 on Mondays this term), I would be seeing all that devastation in person. A friend of mine, whom I phoned this morning being very worried (he was in a flat at the last floor of a very old building), described the situation as "Via XX Settembre looks like Stalingrad in 1943". He's fine and now he's back in Rieti. My landlord says that my flat in L'Aquila is relatively intact, despite a nearby building and Porta Napoli being completely destroyed. I saw them on TV in a shooting from a helicopter. Quite a sad experience. I and my mother have received dozens of phone calls since this morning asking how I was. (And, BTW, today I first got a number of edit conflicts on Wikipedia on a non-talk page, 2009 L'Aquila earthquake.) --A. di M. (formerly Army1987) — Deeds, not words. 21:23, 6 April 2009 (UTC)

(As for masonry buildings, at least they make large fires in towns nearly impossible compared to wooden ones. Very recent buildings tend to be made of reinforced concrete and are reasonably resistent to both quakes and fires, but there are so many old buildings in Italian towns, especially in town centres.) --A. di M. (formerly Army1987) — Deeds, not words. 21:23, 6 April 2009 (UTC)

• How powerful feeling was the quake where you were when it hit? Any damage at all? At 63 km away, could you walk a straight line without looking drunk? Greg L (talk) 23:51, 6 April 2009 (UTC)

I felt it worse than the 4.0 quake of 30 March, which happened when I was in L'Aquila, few kilometres from the epicentre. It was somewhat frightening, but there has been no damage at home (a 1996 reinforced concrete building, I would have been very surprised if there had been), and I'm not aware of any major damage in Rieti, though I have heard of some small cracks in old buildings in nearby towns. (As for "could you walk a straight line without looking drunk", I was in bed trying to sleep — it was 3:32am here — when I felt it, so I don't know.) --A. di M. (formerly Army1987) — Deeds, not words. 09:44, 7 April 2009 (UTC)

Quark

Hey A. di M., how do you think this article is looking, in general? —Anonymous Dissident^Talk 09:39, 21 April 2009 (UTC)

The part I've read so far looks pretty well. Now I'm taking a more careful read; if I find something wrong with it, I'll fix it or point it out. --A. di M. (formerly Army1987) — Deeds, not words. 09:48, 21 April 2009 (UTC)

What do you think: FAC or GAN? I'll be asking Headbomb too; I think you both should be consulted as you the two of you are certainly key contributors. —Anonymous Dissident^Talk 13:53, 22 April 2009 (UTC)

I'd go with a GAN first, and a FAC shortly after if the GAN succeeds, for the reasons TimothyRias gave. (There are many fewer grammar nazis at GAN...) :-) --A. di M. (formerly Army1987) — Deeds, not words. 14:03, 22 April 2009 (UTC)

"Compromise"

There are problems with your compromise. If Strong interaction is to be level 2, it begs the question why weak interaction is not as well. But we can't have that because it's not logical and ruins the structure more. Further to that, the color charge and strong interaction sections really should be together, in the properties section; the two rely on each other (I remember writing the bits about color charge, and they logically lead from one to the other). I contend the old version is better. I don't mean to come across as combative here, but I really don't comprehend the sudden changes in this article's format. It was fine – even Markus, our closest reviewer, said so. It doesn't make sense and it's ruining the article's stability. Its standard and quality decreases every time content is reshuffled and taken out of the place where it was written. —Anonymous Dissident^Talk 13:28, 29 April 2009 (UTC)

The point is that color confinement is the most obvious consequence of the strong interaction, so it makes little sense to have them splitted apart. But I agree that my version isn't alright because it treats strong interaction and weak interaction differently. Logically, Headbomb's version would be even better. If you want to keep "Strong interaction and color charge" in "Properties" and "Color confinement" on its own (to avoid making "Properties" too large), you should at least move the stuff about gluons in the former, as gluons are mediate strong interactions in general. I'll give that a try. --A. di M. (formerly Army1987) — Deeds, not words. 18:49, 29 April 2009 (UTC)

Your comment about the colon in DA

But that would leave the "sea of blue", and we know that the community objects to that. Tony (talk) 10:45, 2 May 2009 (UTC)

I didn't say that it's desirable, I just said that it was possible in principle, in response to the statement that it was impossible to deprecate autoformatting without unlinking dates. (This is irrelevant now that there have been all those RfCs about links, but it wasn't in August when people started unlinking dates to disable autoformatting, which I guess is the time which the fifth proposed finding of fact refers to.) --A. di M. (formerly Army1987) — Deeds, not words. 10:58, 2 May 2009 (UTC)

Template:xt

Hi! You've added a feature to report an error for pages that use {{xt}} directly. Would you mind also fixing the pages that do so? These pages now have a big red warning message instead of the normal output of {{xt}}.     — SkyLined (talk) 21:31, 26 May 2009 (UTC)

Done. --A. di M. (formerly Army1987) — Deeds, not words. 23:18, 26 May 2009 (UTC)

Thanks!     — SkyLined (talk) 13:43, 27 May 2009 (UTC)

Temperatures in Custard

No need for excess precision here. These are approximate ranges and depend on the exact ratio of milk to eggs, the amount of sugar and salt, etc. etc. McGee says "Exceed the coagulation range by just 5 or 10°F and the network begins to collapse..." (http://books.google.com/books?id=oWqlY5vEafIC&pg=PA93&dq=custard+curdling+setting+temperature&ei=GA5RSpDaKZnCzgTY6OnmAg). I am not sure what a useful way is of converting this to °C. --macrakis (talk) 20:49, 5 July 2009 (UTC)

I don't think 6 °C sounds any more precise than 5 °C, especially in such a context. Rounding to 5 °C would be quite arbitrary. --A. di M. (formerly Army1987) — Deeds, not words. 09:25, 6 July 2009 (UTC)

wrong Blackmore

Hi, That is the correct Blackmore, Denis Blackmore. I am more than 100% sure, no big deal though. I'll go ahead and change it back. Regards, --Aminhungryboy (talk) 22:13, 7 July 2009 (UTC)

    I am terribly sorry, I didn't realize my mistake.  Terribly sorry, thanks for noticing it.  Regards, --Aminhungryboy (talk) 22:16, 7 July 2009 (UTC)

I had looked for a physicist in Blackmore (disambiguation), but he was listed as a mathematician, so I missed him, so I just removed the link. Thanks for fixing that. --A. di M. (talk) 09:08, 8 July 2009 (UTC)

Thank you for making WP:NODRAMA a success!

Thank you again for your support of the Great Wikipedia Dramaout. Preliminary statistics indicate that 129 new articles were created, 203 other articles were improved, and 183 images were uploaded. Additionally, 41 articles were nominated for DYK, of which at least 2 have already been promoted. There are currently also 8 articles up for GA status and 3 up for FA/FL status. Though the campaign is technically over, please continue to update the log page at WP:NODRAMA/L with any articles which you worked during the campaign, and also to note any that receive commendation, such as DYK, GA or FA status. You may find the following links helpful in nominating your work:

• T:TDYK for Did You Know nominations
• WP:GAC for Good Article nominations
• WP:FAC for Featured Article nominations
• WP:FLC for Featured List nominations
• WP:FPC for Featured Picture nominations

Again, thank you for making this event a success! --Jayron32.talk.say no to drama 02:16, 23 July 2009 (UTC)

Quark

Hi, A. di M.. Thanks again for your assistance with Quark. Headbomb and I are currently in a disagreement about the structure of the Etymology section. I feel this one is better, and he prefers this one. I think a third opinion would be good. What do you think? Best, —Anonymous Dissident^Talk 23:20, 24 July 2009 (UTC)

I prefer the version in which the names are explained in the same order as they were originally proposed, i.e. the one present now (as of 16:08 UTC), whose-ever it is (the first diff link is broken and I got dizzy when wading through the revision history of Wednesday afternoon). --A. di M. 16:10, 25 July 2009 (UTC)

		The E=mc² Barnstar
		For your help in bringing quark to FA-level. Headbomb {ταλκκοντριβς – WP Physics} 06:55, 31 July 2009 (UTC)

D'oh! Wanted to give one back to you, but Anonymous Dissident already did that! --A. di M. 09:35, 31 July 2009 (UTC)

Feel-free to co-sign his barnstar, I'm sure AD won't mind (I know I won't :P).Headbomb {^ταλκ_{κοντριβς} – WP Physics} 15:37, 31 July 2009 (UTC)

tutorial on linking skills

Hi, we talked about this at WP:LINK a while ago. I've made a start. Part of the aim is get WPians to realise the potential for building skills in this field, a much-neglected issue. People seem to think you just bung in the links without much thought. Your feedback would be appreciated. 14:53, 26 July 2009 (UTC)Tony (talk)

Incredible timing, see my very last contribution! I'll take a look at it. --A. di M. 16:16, 26 July 2009 (UTC)

Thanks for your feedback, A. Hiatus now, partly because I was so put off by Hans Adler's feedback; I hope I go back to it. Tony (talk) 10:45, 2 August 2009 (UTC)

Five min.

I think we're both right; but the reason you're right is that some (especially traditional) units are a special case. We can speak of 9.2 mm, or a stock price of 9.50, but not of 9.3 minutes (rather 9 min., 18 sec.). Therefore 9 mm or a price of 9 is expected; but nothing prevents five minutes. Five seconds is a harder case; there may be a distinction between conversational and scientific usage. Septentrionalis PMAnderson 20:39, 31 July 2009 (UTC)

I think it is more an issue of intended precision than of which units: I would not use a numeral in "I walked about two kilometres this morning" if that is a guesstimate of mine as opposed to a measurement of any sort. OTOH I would write "5 minutes" if it's intended to be precise to within a minute or better (for example, instruction on how to cook something in a microwave oven). --A. di M. 21:40, 4 August 2009 (UTC)

Nineteenth-century

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

---

Oh do feel free to use this; you're not alone, and when MOS gets like this, the unsupported opinions of the MOS regulars deserve to be ignored. (Noetica is not unsupported, but xer actually judgment supports nineteenth-century). Septentrionalis PMAnderson 16:24, 19 August 2009 (UTC)

Where will you seed your propaganda next, PMAnderson? I said I like the word form, and use it often enough away from Wikipedia. But unlike you, I readily discern what is best for the Project, and adapt to that. I suppress my own predilections in favour of elegant, robust, and popular guidelines that work. I do not impose my preferences on others, get it?

–_⊥^{¡ɐɔıʇǝo}Noetica!^T– 09:55, 21 August 2009 (UTC)

Not here, please. Keep drama confined to areas traditionally dedicated to it. This page is for requesting my attention to something, or for constructive comments on my work on Wikipedia (though the latter more properly belongs to the talk pages of the pages where such work is done). --___A. di M. 10:02, 21 August 2009 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

IPA for English

I understood "standard British" to be RP, but this might be better. As for bit-kit in SA and you/ewe, could you add those distinctions to IPA chart for English dialects, or make sure that I got it right if I get there first? kwami (talk) 20:29, 31 August 2009 (UTC)

I'll give it a try, but putting consonants and vowels in different tables makes it somewhat tricky. --___A. di M. 20:38, 31 August 2009 (UTC)

Done. (It took me a while to figure out how to split that table row.) BTW, according to the article (I'm no expert in that), bit-kit doesn't seem to be phonemic, but I think it's a good idea to mention it anyway because it's the only case I am aware of in English of an allophonic variation of a vowel conditioned by the syllable onset as well as its coda. --___A. di M. 01:26, 1 September 2009 (UTC)

Speed of light

Thanks for your several improvements to Speed of light. I hope you will continue to contribute to the article; knowledgeable help like yours is needed to bring the article back to FA quality. Also, I hope you will contribute to the talk page discussions on how to improve the article. The manner of discussion there falls somewhat short of Wikipedia's collaborative ideal. That might be improved with participation of additional editors with knowledge in the field, who are not battle weary from months of strife. Perhaps you can recruit more of your colleagues at Wikipedia:WikiProject Physics to pitch in. Thanks again. —Finell (Talk) 10:06, 3 September 2009 (UTC)

Ta for fixing MoS

I really am a computer klutz. Tony (talk) 14:53, 3 September 2009 (UTC)

You have serious legal problems

Well, not really, but I think I ought to warn you that the guidelines on signatures do not allow the usage of images. I'm afraid that the (apparently recent) change of your signature will have to be reversed.

For all that's worth, you might try to apply colouring to the conveniently three words of your user name to resemble the Italian flag. Or you might go for something original... I am aware of a couple of signature workshops out there, though I have to find the links first. :-) Waltham, The Duke of 06:23, 7 September 2009 (UTC)

No picture is used, they are underscores with background colours. --___A. di M. 16:29, 7 September 2009 (UTC)

Hm, that's something for your FAQ page, should you ever decide to create one. I thought it was an image because of the link; it's a very convincing flag substitute. I commend you for your clever and elegant idea. Waltham, The Duke of 22:57, 7 September 2009 (UTC)

Wikipedia:Arbitration/Requests/Case/Speed of light

An Arbitration case in which you commented has been opened, and is located here. Please add any evidence you may wish the Arbitrators to consider to the evidence sub-page, Wikipedia:Arbitration/Requests/Case/Speed of light/Evidence. Please submit your evidence within one week, if possible. You may also contribute to the case on the workshop sub-page, Wikipedia:Arbitration/Requests/Case/Speed of light/Workshop.

On behalf of the Arbitration Committee, Hersfold ^(t/a/c) 04:01, 9 September 2009 (UTC)

ISO 8601

I note that some I.P. editor edited ISO 8601 to strip out a desperately-needed citation to the ISO themselves and introduced a huge swath of un-cited fairy tale. I wonder if an editor from WT:MOSNUM is logging out to do this. A Check User on that I.P. address would be interesting, wouldn’t it? I added some {citation needed} tags to the fairly tale stuff. If this mysterious I.P. editor can’t back up what he/she just added with clear citations that speak precisely to the point, it ought to get tossed, don’t you think? Is there any grey area to that added material? If so, I suppose we should let the editor try to cite that garbage. Or, do you think any rational reading of ISO 8601 makes it suitably clear? That the I.P. editor wrote of “private hand-written notes” makes it clear enough that he/she is just lying, is deluded, or is simply intentionally fabricating crap to POV-push. Greg L (talk) 00:22, 14 September 2009 (UTC)

Dunno 'bout "an editor from WT:MOSNUM", since that IP has edited that article since May 2008; I guess a checkuser could only be requested if we had a suspect for someone in particular. (And dunno 'bout "any rational reading of ISO 8601": I don't own a copy of the standard; once upon a time I had found a draft of it somewhere, but I can't be arsed to look for it again.) Just leave the cn tags for a while and try and delete the stuff again if it isn't sourced in a month or so. --___A. di M. 01:26, 14 September 2009 (UTC)

On further thought, {{cn}} is for statements which you think should be sourced, but have no particular reason a priori to believe that they should be removed. For statements which you do believe to be incorrect, there's {{disputed}}. I've changed the article in view of that. --___A. di M. 10:05, 14 September 2009 (UTC)

BTW, looking at the talk page of the article, the view that the standard also applies "to a private diary entry" appears to have originated from User:Richardrw, who hasn't edited since September 2008. Maybe the IP who reverted you recently was him? --___A. di M. 10:14, 14 September 2009 (UTC)

YYYY-MM-DD numerical date format in footnotes

Hello, an RfC is now open for your comments on this issue at Wikipedia:Mosnum/proposal_on_YYYY-MM-DD_numerical_dates. -- Alarics (talk) 09:11, 30 September 2009 (UTC)

Hypothetical with lasers

With regard to Kilogram, indeed. But one couldn’t operate a laser for 285 continuous years either. Moreover, even if one did manage to operate a laser continuously for 285 years, there still wouldn’t be that many photons in existence at one time because of interstellar dust, which would absorb some of the photons. One could properly address the idiosyncrasy you raised by adding “that started out as…”, but why bother?

The point of my revising that example to give a diameter was to provide the reader a sense of ‘volume’ to the beam when we are talking about a quantity of photons. Length is one key aspect for a quantity; diameter and (a very bright) intensity provides the rest. It is overly abstract, IMO, to talk about a certain number of photons, provide a length dimension, and fill in the rest of the picture with only a beam power. It is easier, to imagine a four-centimeter-diameter beam that has a brightness of a million watts for each of its 12-odd square centimeters; everything is there to form a picture in the mind’s eye. I’d bet that a significant fraction of the readers look down at their hand when they read that and form a circle with their middle finger and thumb (about four centimeters) and ponder the implications.

I trust you double-checked my math in both versions? Greg L (talk) 20:20, 5 October 2009 (UTC)

Yeah, that's a hypothetical situation anyway. (Is there a particular reason for that value of intensity, i.e. a reason why you'd rather want a reader imagining a 4 cm diameter beam with a 1 MW/cm² intensity than, say, a 4 mm diameter one with a 1 MW/mm² one, or a 40 cm diameter one with a 100 MW/m² one? I usually dislike making examples more complicated than they need be, but you might have a point. For example, I'd rather say "you'd need 40,000 books of 1000 pages each" than "you'd need 40,000,000 pages" as 1000 pages is a typical value for a largish but realistic book. Is 1 MW/cm² a largish but realistic value for a HeNe laser intensity? If so, what you did has a point.) BTW, I've double-checked the value right now (I hadn't before): 10×10⁶×285×10^7.5 equals about 9.01×10¹⁶ (where 10^7.5 is a handy approximation for the number of seconds in a year) which is close enough to c², and given this, the second one looks plausible to my eyeball. ___A. di M. 20:37, 5 October 2009 (UTC)

I was intent on having a laser power in the range of the Air Force’s laser-equipped 747 (another link) for shooting down ICBMS. I believe they are doing tests at 1 MW and plan to go to 10 MW. I first tried 1 MW but that produced a beam length of 2,850 light years, which is a bit long. So I chose 10 megawatts and that shortened the beam length.

I have been “into” astronomy since junior high (late 60s) and 200-some-odd light years is a nice length because it reaches to stars that can be seen with the naked eye. So when I revised the example to provide a diameter, I chose a beam diameter (4 cm) because it was a round number that came close to an area of 10 square centimeters, used a beam intensity of 1 MW/cm², and that only slightly increased the beam power to 12.56 MW (shortening the length from 285 light-years to 227). Thus, all these terms are still solidly within the realm of human comprehension. And, for the especially technically savvy readers, they can do the math and figure out that the beam I’ve described is just about the size and intensity of the focused laser spot as it burns through an ICBM.

It’s also fun to imagine, that if the chemical laser on the 747 is, for instance, 25% efficient, operating the thing at 12.6 MW for 227 continuous years means that all the chemical reactants become four kilograms less massive after being run through the laser. Greg L (talk) 21:08, 5 October 2009 (UTC)

My opinion is that the point is showing how incredibly much energy is in a kilogram, using realistic values for all but the "outermost" dimension (i.e. 1.256 MW times 2,270 ly or whatever rather than 12.56 MW times 227 ly) is more effective. (By comparison, you'd rather want to say that it'd take more than 92 books of 1000 pages with 50 lines of 80 digits each to write down 9⁹⁹, than say that it'd take more than 9 books of 10,000 pages each.) So, while you're at it, you could also say "... which is close to the greatest intensity ever achieved so far in a laser." But maybe that'd be overkill. Worth a try? ___A. di M. 22:05, 5 October 2009 (UTC)

You’re savvy enough to be doing the math. When you do so, you know there is an underlying power value, like 12.56. Remember though, the example given uses a nice round number (4) for the diameter and a (very) round number (1) for the beam intensity. That the math comes out to 227 light-years isn’t a problem; something has to give and it’s better that it be the input values. Greg L (talk) 22:42, 5 October 2009 (UTC)

My point was about the orders of magnitudes, not the values. You'd better give an intensity value which is close to the largest ever achieved one (and maybe even state that) than one about ten times as large, and I can't see why 2,850 (or 2,270) light years would be "a bit long" whereas 285 (or 227) wouldn't: they are hypothetical examples anyway. (As for roundness, I fully agree that I'd use round numbers for the diameter and the intensity and whatever comes out for the length.) ___A. di M. 00:05, 6 October 2009 (UTC)

Yes, ten megawatts is close to the maximum; it’s what they’ve long planned for that 747. I subscribe to Aviation Week & Space Technology and, if I recall correctly, they’ve recently flow around and dumped 1 MW into an on-board calorimeter. Once they get the thing throwing beams away from the plane and get everything shaken out, it’s supposed to be downing ICBMs with 10 MW. A beam flux of 1 megawatt per square centimeter and a four-centimeter-diameter beam equates to 12.6 MW, which is certainly close to this real-world (but exceedingly powerful) laser; particularly since the example doesn’t even mention the 747. The whole point of that sentence is to give readers a much better appreciation of these big-ass numbers like “2.864×10³⁵ photons”; I wouldn’t have been the least bit surprised if my 4-watt, Inova T4 could have produced that quantity of photons after running its lithium cell down. Base-ten math sneaks up on you quickly. Greg L (talk) 02:18, 6 October 2009 (UTC)

P.S. As for the order of magnitude for the distance, there’s not much you can see with the naked eye at 2,850 light-years. But when you look up at the night sky, most of the stars you see are in this range (on the order of hundreds of light years). For astronomer-types, a value of 227–285 light-years simply is… *typical*. In fact, a very bright star Canopus (magnitude -0.7) is right around this distance. So if one is going to use a unit of measure like the light-year, one might as well make it a familiar value for those who have some facility with that unit of measure. That one can obtain a astronomically familiar distance using the example of a laser power that is exceedingly close to what is planned for a real-world, big-ass missile killer like Boeing YAL-1 makes for a nice fit.

I don’t see the need to state in the body text nor add a footnote regarding the Boeing YAL-1 or the power of the laser chosen for the example. You and I find this minutia to be interesting but it is probably a bit too far off-topic from the kilogram. Anyone who has waded that far into the article is technically astute enough to read what’s there and easily appreciate the crux of the concept: that it takes an awfully bright light source (and a l-o-n-g time) to create a quantity of 2.864×10³⁵ photons. I was so astounded by these numbers I quintuple-checked my math. Greg L (talk) 02:47, 6 October 2009 (UTC)

Fair enough. My concern was that most readers won't know whether 1 MW/cm² is an easily obtained intensity, a pushing-the-borders intensity, or an unrealistic large intensity unlikely to be obtained within their lifetimes, and something suggesting that it's the second one would be useful. But I can't see a way to do that without being too distracting, right now. (Of course, mentioning Boeing YAL-1 explicitly is way too much, I agree. Maybe "... a beam intensity of 1 megawatt per square centimeter—close to the current technological limits—and a length ..." or something like that?) As for the distance, I hadn't even thought in terms of which visible stars are there. Indeed, to an amateur astronomer with no particular knowledge of relativity (or who had never thought of E = mc² in this terms) that would get the point across awfully well. (But anyone able to understand that "hey, 227 light years! that's long!" is also able to understand that "hey, 2270 light years! that's f***ing long!".) ___A. di M. 09:45, 6 October 2009 (UTC)

(As for the maths, the photon energy cancels out; you just need to check that the power of the laser multiplied by the time it takes to emit the beams equals 1 kg × c².) ___A. di M. 09:49, 6 October 2009 (UTC)

Quoting you: As for the maths… yup, understood; that’s the way I did it. However, that math only confirms that the beam contains one-kilogram of energy; it doesn’t confirm that the beam contains 2.864×10³⁵ photons, each of which is oscillating at the frequency of a helium-neon laser (the subject of the sentence). All the information you need to double-check this value are these: 1.356392733×10⁵⁰ Hz (NIST cite), and two values from our Meter article, one of which (the velocity of light) is in the first paragraph, and the other (the currently accepted wavelength of a helium-neon laser) is in this section. Sanity check please? Greg L (talk) 16:08, 6 October 2009 (UTC)

Seems right to me. (Normally I'd have keyed "3e8" into the calculator, but after this, typing "299,792,458" has become a kind of an automated gesture for me.) :-)___A. di M. 19:13, 6 October 2009 (UTC)

Faster-than-light observations and experiments

Sorry I messed up this section of Speed of light. Thanks for cleaning up after me. Finell (Talk) 03:54, 11 October 2009 (UTC)

Articles you might like to edit, from SuggestBot

SuggestBot predicts that you will enjoy editing some of these articles. Have fun!

Stubs Strangeness June Gelatin-silver process Antineutrino Syllable coda Glueball Tuesday Fine structure La Massana Up quark Fundamental representation Joule heating Down quark May Surely You're Joking, Mr. Feynman! Charm quark Neutron activation Encamp Lattice QCD

Cleanup Color charge Monday Graviton Merge Parton (particle physics) Soldering iron Deuterium Add Sources Neutralino Polarization density Strange quark Wikify Ramble On Jochen Mass From the Top Expand Meson Quantum electrodynamics Electromagnetic field

SuggestBot picks articles in a number of ways based on other articles you've edited, including straight text similarity, following wikilinks, and matching your editing patterns against those of other Wikipedians. It tries to recommend only articles that other Wikipedians have marked as needing work. Your contributions make Wikipedia better -- thanks for helping.

If you have feedback on how to make SuggestBot better, please tell me on SuggestBot's talk page. Thanks from ForteTuba, SuggestBot's caretaker.

P.S. You received these suggestions because your name was listed on the SuggestBot request page. If this was in error, sorry about the confusion. -- SuggestBot (talk) 22:30, 17 October 2009 (UTC)

Fixed Convert ft&in default-rounding

Talk-page: Template_talk:Convert#Change_to_default_rounding_ft-inches

Hi. Wikid77 here. I am just sending this message to notify and thank the recent users who spent time to document problems in Convert rounding. The precision HAS BEEN FIXED, today, for feet-and-inches, as noted in the talk-page. There are over 19,250 articles being reformatted, and many will show the improvement (up to 5 cm, or 2 inches) because they use the default-rounding levels. Next week, I will try to fix some other rounding problems as well. Thanks again. -Wikid77 (talk) 18:00, 1 November 2009 (UTC)

numerical

Hi. Re the part of your edit summary, "that's the whole point on which the ArbReq happened." - I'm not familiar with the ArbReq that you are referring to. Could you direct me to where this was discussed? Thanks. --Bob K31416 (talk) 16:49, 5 November 2009 (UTC)

If you really have that much guts, it's Wikipedia:Arbitration/Requests/Case/Speed of light. But beware... (The case is closed now, so you can't break anything, but you might be shocked...) ___A. di M. 16:54, 5 November 2009 (UTC)

Don't worry. I mean no harm, and I don't think I will do any harm. I think I might be able to help the situation, and I will try to be sensitive to the problems that this article has had in discussions of it in the past. One thing I was trying to add to my message above, but was cutoff by an (edit conflict): "It looks like your edit summary was too long to fit in the space provided, so could you complete it here, and maybe expand on it?" --Bob K31416 (talk) 17:03, 5 November 2009 (UTC)

Sure. The edit summary was intended to end with "fixes the *number* 299,792,458, not how fast light goes."

Yes, that sounds obscure, so I'll try to explain: "299,792,458 m/s" is a value; "299,792,458" is a numerical value. A value is a numerical value multiplied by a unit. The value of speed of light is just what it is, and the metre per second is 1/299,792,458 of it. So it is the numerical value (the 299,792,458) that is fixed, not the value itself. (See point 1 of this for more elaboration of that.) ___A. di M. 17:10, 5 November 2009 (UTC)

Thanks. Unfortunately, the link to the Redbook isn't working. I felt that "value of c in metres per second" said the same thing as "numerical value of c in metres per second", but since you feel strongly that it doesn't, I'll leave it at that.

To change subjects, my recent experience on the Speed of light discussion page suggests that there are some serious problems with being able to conduct a reasonable discussion there. --Bob K31416 (talk) 20:28, 5 November 2009 (UTC)

The relevant passage of the Red Book was quoted verbatim, but you should be able to find the original text by googling for "IUPAP Red Book". And yes, many readers would understand that "value of [quantity] in [unit]" means the numerical value (i.e. the number 299,792,458), but since the cost of being pedantic to be on the safe side is just one lousy word, I can't see a strong reason to omit it. (And if there weren't problems, there wouldn't have been any RfArb...) ___A. di M. 21:19, 5 November 2009 (UTC)

1)Your edit summary: "The definition of the metre fixes the *number* 299,792,458, not how fast light goes."

2)Redbook: "A physical quantity is expressed as the product of a numerical value (i.e., a pure number) and a unit."

3)Article excerpt, with brackets to denote the word that was restored:

"As a result, the [numerical] value of c in metres per second is now fixed and exact, by definition of the metre."

From the above items 1 and 3, I think your point is that, without "numerical", the term "value of c " means how fast light goes, instead of meaning 299,792,458 metres per second. Is that your point? --Bob K31416 (talk) 06:12, 6 November 2009 (UTC)

Yes, except that the numerical value is the number 299,792,458, and the value is the quantity 299,792,458 m/s, which, due to the definition of the metre, is how fast light goes. Just a quibble on wording, but after the ArbReq I think it is essential to use terms which cannot be misunderstood. ___A. di M. 10:50, 6 November 2009 (UTC)

Thanks. From your remark "the value is the quantity 299,792,458 m/s", and from the definition below, I think we are agreed that "value of c in metres per second" means the numerical quantity 299,792,458 m/s. Is this "value of c in metres per second", fixed and exact as a result of the definition of the metre? --Bob K31416 (talk) 15:34, 6 November 2009 (UTC)

What you mean by "numerical" exactly? 299,792,458 m/s is not a pure number, it has units. It exactly equals the speed of light because of how the "m" and "s" are defined, but in principle we don't know exactly how long the metre is (not that the uncertainty in the present definition of the metre isn't about three orders of magnitude smaller than that of almost any other measurement of length). One might say that *in principle* possible that the speed of light changes in time (for suitable definitions of "speed of light", at least), but the metre per second would itself change; so the 299,792,458 m/s would change, too. I strongly believe that that's impossible, but for reason completely unrelated to the way the metre is defined. On the other hand, everyone agrees that the *pure number* 299,792,458 is an artefact of a choice of measurement system, it is exact by definition, and it cannot change (unless we change the definition of the metre). I'm not entirely sure of what the problem is. ___A. di M. 18:57, 6 November 2009 (UTC)

Re "What you mean by 'numerical' exactly? 299,792,458 m/s is not a pure number, it has units." -

I agree that the numerical quantity 299,792,458 m/s is not a pure number. Please reread my previous message and note that I used the term "numerical quantity" as it is used in the definition for "value" from the Merriam-Webster dictionary, as mentioned below. Specifically, the term "numerical quantity" means pure number and units, which is the "value" that is defined below. Could you then answer the question in my previous message? Thanks. --Bob K31416 (talk) 22:05, 6 November 2009 (UTC)

Additional remark. Re "One might say that *in principle* possible that the speed of light changes in time (for suitable definitions of "speed of light", at least), but the metre per second would itself change; so the 299,792,458 m/s would change, too. -

Although I'm not sure what you mean, we may disagree here. Even if the physical characteristic of light called speed, becomes faster or slower for some reason, I believe that 299,792,458 m/s would still be the exact and fixed value of the speed of light because of the 1987 definition of the metre. --Bob K31416 (talk) 01:56, 7 November 2009 (UTC)

Yes. If I understand your question correctly, the answer is this: Imagine the light is twice as fast on Tuesday than it is on Monday. Then the metre would be twice as long on Tuesday than it is on Monday. Thus, the dimensionful quantity 299,792,458 m/s would be twice as big on Tuesday (because one of the factors in it would be twice as big), while the pure number 299,792,458 would stay constant. Now, according to my POV the dimensionful quantity 299,792,458 m/s cannot change, either, but that's for reasons unrelated to the definition of the metre. OTOH, everyone (who understands the issue) would agree that the pure number 299,792,458 cannot possibly change because of the definition of the metre. ___A. di M. 10:44, 7 November 2009 (UTC)

This apparently is a difficult subject for us to communicate. But I'll try a little more to communicate by following up on your hypothetical situation of light being twice as fast Tuesday as it is on Monday. On Monday, if someone was to ask me what the value of the speed of light was, I would answer 299,792,458 m/s . On Tuesday, if someone was to ask me what the value of the speed of light was, I would answer again 299,792,458 m/s . (Please note the definition of value in the section below.) I would give the same answer since the value of the speed of light is fixed and exact because of the 1987 definition of the metre. In effect, this definition of the metre has assigned a fixed and exact value for the speed of light which is 299,792,458 m/s .

I recognize that although I am giving the same fixed and exact answer each day for the value of the speed of light, the speed of light itself has changed and become faster. This odd situation is because of the definition of the meter. --Bob K31416 (talk) 13:34, 7 November 2009 (UTC)

That wouldn't be exactly the same answer, as by "metre" you'd mean a different thing on Tuesday than on Monday. On the other hand if I asked "how many metres does light travel in one second?", the question would have two different meaning but the answer would be exactly the same ("299,792,458") on both days. ___A. di M. 14:08, 7 November 2009 (UTC)

It looks like we can't make any more progress in our discussion, so it's probably best to end it here. Thanks for the discussion. Best regards, --Bob K31416 (talk) 14:12, 7 November 2009 (UTC)

Definition of value

Please note the relevant definition of "value" in the Merriam-Webster Dictionary[2]

a numerical quantity that is assigned or is determined by calculation or measurement <let x take on positive values> <a value for the age of the earth>

--Bob K31416 (talk) 06:24, 6 November 2009 (UTC)