Talk:Non-SI units mentioned in the SI

Misc

Isn't year accepted for use with the SI? —Joe Llywelyn Griffith Blakesley _{talk contrib} 01:31, 2 June 2007 (UTC)

Also nautical mile is now accepted. 69.218.224.191 22:24, 26 August 2007 (UTC)

Hectare

This template contains a mixture of information from both sources referenced as well as some that is not found in either (such as square degree). The NIST document is, according to its foreword, meant to reflect the 7th ed of the BIPM source document. The BIPM website referenced is the 8th ed. There are differences between the two documents and I can't determine whether the differences are due to differences in the two editions of the BIPM source (I haven't seen the 7ed.) or whether more than just the spelling has changed between the BIPM 7th ed. and the NIST version. A new version of the NIST doc is due to be published, reflecting BIPM 8th ed. Until then the NIST document is probably out of date. This template needs reworking to reflect the latest BIPM source. That is beyond my scope at this point. One thing that I do understand is that BIPM regard hectares as being in the same category and hence described in the same table as minutes, hours, days, degrees, minutes, seconds, litres and tonnes. These are all units accepted for use with SI. So I will move hectare up to the first table. Bleakcomb (talk) 12:06, 17 March 2008 (UTC)

Well, a year has passed and the table still lists square degree, claiming to cite BIPM's SI brochure (8th edition) which contains not a word about square degree; neither does NIST's brochure. I am removing square degree from the article since no traceable reference has been given, and the claimed reference was false. I wonder who originally added it and why. --Jmk (talk) 09:23, 5 May 2009 (UTC)

Revisions and rude editing behavior

I had revised the tables in this page according to the official SI specification as the existing text took material out of context without consideration of foot notes and prose of the original documents. However, User:Jc3s5h rudely intervened in my edits while doing so and restored the prior version without discussion and obviously without consulting the documentation. Further the user continued to apply their own modifications without regard of ongoing edits. The old version, and a version installed by this user simply do not reflect the standard's content accurately. As an example, the logarithmic units are explicitly mentioned to be officially accepted for use, while the old and User:Jc3s5h's edits conflict the document. Kbrose (talk) 21:51, 28 August 2010 (UTC)

The language in Kbrose's version was not taken from the official document and does not accurately reflect the content of the official documents, in that it omits many units that are indeed mentioned, including atomic units, natural units, and all the units in table 9 of the source. If there is anything in the version I was introducing, due to significant items in footnotes or text, I would like Kbrose to point them out.

I would also like to ask, if I made my edits " obviously without consulting the documentation" how is it that I made the page numbers agree with the 2008 edition of Taylor and Thompson, and how is it that I noticed that the new edition has an additional editor, Thompson? Jc3s5h (talk) 22:08, 28 August 2010 (UTC)

I would also point out that Kbrose's statement, "the logarithmic units are explicitly mentioned to be officially accepted for use" is not exactly true. On page 35 of Taylor and Thompson we find "Tables 8 and 9 contain non-SI units that are used by special interest groups for a variety of different reasons. Although the us of SI units is to be preferred for reasons already emphasized, authors who see a particular advantage in using these non-SI unis should have the freedom to use the units that they consider to be best suited to their purpose."

Perhaps you should actually read the specification, which states on page 127 of the SI Brochure: The units neper, bel, and decibel have been accepted by the CIPM for use with the International System, but are not considered as SI units." Kbrose (talk) 22:59, 28 August 2010 (UTC)

I believe it would be best to stick to the exact phrases used in the source rather than inventing phrases such as "Units officially accepted for use with the SI" because the source indicates different degrees of acceptance for various units.

Also, for those readers who elect to read the source, it would be best to keep the table structure used in the source, since the prose in the source makes frequent reference to the tables (e.g., page 35 begins "Tables 8 and 9 contain non-SI units...) If the table structure of this article matches the source, it will easy for readers to apply the prose statements to the appropriate units in the article. Jc3s5h (talk) 22:21, 28 August 2010 (UTC)

Funny fact is that the tables here never were in the format of the standard. If you had elected to wait until editing was finished and not jumped in with your own versions, disrupting the updating, you would have seen more complete tables, as presented now. The original tables from the SI docs cannot be used here verbatim without also duplicating foot notes and prose to explain the material, as context is lost. Kbrose (talk) 22:41, 28 August 2010 (UTC)

As far as jumping to conclusions about an article that seemed to be finished (or as finished as anything gets on Wikipedia) I think we are both guilty of not using {{In use}}. The article in its present form gives substantially different indications about the acceptability of certain units that appear in table 8 in the source. The article tells us that the logarithmic units are "Units officially accepted for use with the SI" while some units like the nautical mile and bar are "Common units not officially sanctioned". But all the units in table 6 through 9 are in section 4.1 of the source, "Non-SI units accepted for use with the SI, and units based on fundamental constants", so I don't think it is fair to imply that the last table of the article are less accepted than the logarithmic units, the atomic units, or the natural units. Indeed, the source has a section 4.2, "Other non-SI units not recommended for use", and if any units are to be listed as "Common units not officially sanctioned" it should be the ones described in section 4.2.

When one views the URL provided in section 4.2 of Taylor and Thompson one finds it is a dead link. When one views the URL in the HTML section 4.2 by BIPM, one finds units such as acre, BTU, and calorie. Jc3s5h (talk) 00:27, 29 August 2010 (UTC)

This article is intentionally pro-imperial subverson!

Hectare, litre, metric tonne are NOT units, they are just psedudonyms for SI units with a multiplier (1ha = 10k m2, 1mt = 1000kg) or straight name alternatives (1 Liter = 1 dm3). There is absolutely no reason to include them in this article!

Hectare, liter, metric tonne are not guilty in the same way as the historically legacy, illogical muliplier units of nm, knots and minute of time, etc. are guilty of poisoning the beautiful logic of a completely unified systems of measurements.

My prof says the bureau of measurement experts are like the Vatican and the eastern orthodox theologists. They have been infighting about the filiale's comma and the iota for centuries, even though they should unify and aim to crush the protestant heretics, who refuse to adore the all-important eucharist. Similarly, there should be no petty talk about which base 10 multipliers are allowed for use in SI, but the unified metric crusade should march to uproot the silly anglo-saxon units of measurements.

We had great hope the Airbus company was founded to eventually extirpate the nm, knots, feet, gallon madness from aviation, yet here is no progress, but regress, as even the non-NATO military aviation "feets" under US pressure. Computing, flatscreen TV are imposing inch around the world, metrication is losing much ground day by day. "Experts" issuing bulls against hectare should be shot on sight and then lets march against inch!

Let's revise this article from an "ecumenical" metric point of view and move on versus the "imperial" folk! 91.83.26.110 (talk) 22:47, 5 May 2011 (UTC)

This is article is about the what the SI says. It does not contain any opinion other than the SI's. It doesn't matter if you agree with the SI or not; we're not promoting the SI with this article, just providing information about it. McLerristarr | Mclay1 03:12, 7 May 2011 (UTC)

Angle problem?

Looking at the conversion given between degrees and radians, it seems like the conversion factor was somehow inverted. Currently, the article has "1 deg = (π/180) rad". I'm fairly sure it should be "1 deg = (180/π) rad". Does this need to be fixed or am I just not thinking? —68.170.177.190 (talk) 03:20, 13 May 2011 (UTC)

The article is correct. 1 degree = 1/57 radians (approx). Martinvl (talk) 05:59, 13 May 2011 (UTC)

Light-year?

If this isn't an accepted unit (which surprises me), then shouldn't it go in the lower section, since it's probably quite a bit more well-known than the likes of barn and torr. — Preceding unsigned comment added by 131.111.185.74 (talk) 22:43, 30 January 2012 (UTC)

The SI manual does not define the "year" either, but then which "year" should be defined? Instead, eh SI manual gives astronomers, economists and others all the tools that they need to define their particular "year". Martinvl (talk) 07:46, 31 January 2012 (UTC)

Natural/atomic units

To keep with the listing of units in BIPM table 7, surely one should not omit the duplicate values under atomic units (ħ and m_e)? (Aside: I find it curious that m_e is classified as a natural unit by BIPM.) — Quondum 19:00, 5 September 2012 (UTC)

I would favor following the sources unless a reason to do otherwise can be stated. Although I'm familiar with many of the units mentioned, I'm not familiar with the phrases "natural units" and "atomic units" and don't know what the expectations would be from people who use those phrases on a daily basis. Jc3s5h (talk) 19:31, 5 September 2012 (UTC)

I concur – I've updated the table to reflect the source accurately. One of the problems was the omission of the unit names given in the source; since they start "n.u. of ..." and "a.u. of ...", it is now a bit more obvious what's happening. — Quondum 19:47, 5 September 2012 (UTC)

pH

Should this common measurement of acidity be included here? 199.27.158.217 (talk) 02:12, 25 January 2013 (UTC)

No - pH is not mentioned in the SI Brochure. Another noteworthy ommission is the "year", probably because the word "year" has many definitions, depending on who you are - astronomers use fractions of a day in their definitions, bankers do not. Martinvl (talk) 10:28, 25 January 2013 (UTC)

hPa/kPa

I was under the impression that kiloPascals is the preferred unit to hectoPascals in most applications. The conversions to Bar should probably be in kPa (A trivial decimal place I know) unless I am mistaken. Cheers. — Preceding unsigned comment added by 97.127.185.24 (talk) 19:08, 5 May 2013 (UTC)

I believe that aviation circles prefer hectopascals - on safety grounds - millibars and hPa are identical. Martinvl (talk) 21:14, 5 May 2013 (UTC)

The symbol used in the article for astronomical unit is incorrect

What should be followed in this article is the official BIPM brochure, Edition 8 of which uses ua as the symbol for astronomical unit. The BIPM website incorrectly reports this symbol as au. This article is now incorrect because it follows the website instead of the original pdf. Dondervogel 2 (talk) 15:09, 13 June 2015 (UTC)

The first link provided by User:Dondervogel 2 is to a 2006 version of the SI brochure, with no indication it was ever updated. The second link provided by Dondervogel 2 is to a version of the SI brochure that was updated in 2014. In the period between the two versions, the astronomical unit was "redefined by the XXVIII General Assembly of the International Astronomical Union (Resolution B2, 2012)." [Hyperlink provided in quoted web page.] I see no reason to consider the obsolete version of the brochure to be more official than the current version, nor can I think of any other reason to prefer the obsolete version. Of course, our article should conform to the version we cite. Jc3s5h (talk) 15:27, 13 June 2015 (UTC)

The pdf I mentioned is linked to directly from the BIPM web page. However, I looked again at the BIPM website and see that it also contains a link to separate pdf describing the update. That update does indeed use au (and not ua). So the article is correct after all, but perhaps this inconsistency between the text on the web and the pdf file that is linked from is worth a mention. Dondervogel 2 (talk) 15:43, 13 June 2015 (UTC)

Actually, the article is correct with respect to the symbol, but is incorrect because the au is placed in the "Units with experimentally determined values" section of the table when it should now be in the "Widely used units expected to be used indefinitely" section of the table. The au is no longer experimentally determined; it is now an exact defined value. So of course we should only cite the updated brochure, not the obsolete brochure, once the position of the unit in the table has been fixed. Jc3s5h (talk) 16:00, 13 June 2015 (UTC)

Good point. So the choice is between citing the original 8th edition (with the old value, and symbol ua), or the 2014 update (with the new value, symbol au, and moved to its correct position). Which is preferred? For now I propose we go back to the last correct version (before today's flurry of changes so at least we have a correct baseline) Dondervogel 2 (talk) 16:15, 13 June 2015 (UTC)

I disagree with the MoS following the IAU and BIPM on this. For several reasons, not least of which is that the BIPM may have made history by including an ambiguous notation (atto- + unified atomic mass unit), something that the MoS has liberty to choose separately, especially with reference to a template where such ambiguity impacts automated unit matching. But more overridingly, this must be decided at and specified in WP:MoS, not here (an article in mainspace). —Quondum 17:01, 13 June 2015 (UTC)

I am not persuaded that the BIPM has a goal of choosing symbols that are unambiguous for all units that appear in the brochure, nor that they have any authority to do so. (Of course they have a goal of choosing symbols that are unambiguous within the SI.) It seems to me that since the IAU has declared that "au" is the symbol for the astronomical unit, BIPM's choices are (1) go along with the IAU, (2) make no mention of the au in the brochure, or (3) create a new table for units who's names may be used with SI but who's symbols are not accepted for use with SI.

As for our MOS, the MOS is normally applied to articles that merely use notation that is covered in the MOS; articles which describe the notation are usually treated as exempt from the MOS. Jc3s5h (talk) 17:21, 13 June 2015 (UTC)

Yes, this article should describe the units and their symbols as specified by the body that defines the SI (BIPM). The issue of what symbol should be used by WP articles generally is something for MOSNUM. A proposal to adopt a unique symbol for the astronomical unit in Wikipedia articles encountered strong resistance. Dondervogel 2 (talk) 17:32, 13 June 2015 (UTC)

Agreed. My point is only that the MoS should be decoupled from this article. It currently defers to this article, and I feel that this is inappropriate. But I guess I should deal with that there rather. —Quondum 17:38, 13 June 2015 (UTC)

The MOS defers to this article? Weird. Where do you see this? Dondervogel 2 (talk) 17:50, 13 June 2015 (UTC)

@Dondervogel 2:, where is the proposal to adopt a single symbol for the astronomical unit discussed? As for WP:MOSNUM deferring to this article, not quite. It says:

• In most articles, including all scientific articles, the primary units chosen will be SI units, non-SI units officially accepted for use with the SI, or such other units as are conventional in reliable-source discussions of the article topic (such as revolutions per minute (rpm) for angular speed, hands for heights of horses, et cetera). [Emphasis added.]

The bold link is a link to this article. So the MOSNUM defers to BIPM and other reliable sources; it defers to this article only to the extent this article correctly describes the positions of BIPM and other reliable sources. Jc3s5h (talk) 17:55, 13 June 2015 (UTC)

Conceded – my failing memory is at fault (I previously followed through that link, and assumed this article to be correct as it was corroborated by the version of the SI brochure that I saw; my poor memory reinterpreted this chain). However, MOSNUM should only defer to BIPM etc. as a fall-back; in this tricky case it should make a choice (or explicitly list alternatives). I've hopefully triggered a discussion there. —Quondum 18:14, 13 June 2015 (UTC)

@Quondum:, I think the main discussion was at Talk:Astronomical unit. I will check and get back to you. Dondervogel 2 (talk) 18:23, 13 June 2015 (UTC)

The discussion has not yet been archived. You can still find it here. Dondervogel 2 (talk) 18:29, 13 June 2015 (UTC)

Okay, I'll watch it there too. I think the discussions here and there should pertain only to the article content. I'm more interested in MOSNUM not leaving an editor perplexed, even if it just says "don't fuss too much about the AU/au/ua choice". I'm not too worried about what choice is made. —Quondum 18:39, 13 June 2015 (UTC)

Yes, I now think Talk:Astronomical unit was not the best place to hold that discussion. Perhaps your edit at MOSNUM will trigger a discussion there. Dondervogel 2 (talk) 19:52, 13 June 2015 (UTC)

Impending revision of SI

It seems that the ninth SI brochure will omit any mention of atomic units and natural units, listing only 15 non-SI units (counting 'B' and 'dB' separately, and not counting 'u' that is mentioned as an alternative to 'Da'). The mention of any further units is omitted. I suggest that this article should be updated reflect that brochure once it is officially published. We would then face the choice of removing mention of the further units, making a section for historical tracking of other units mentioned in earlier revisions of the SI. I incline towards the former: using this article to record the (contemporary) position of the SI on this aspect, and limit history of this aspect to a link to the earlier revisions of the SI brochure. —Quondum 19:52, 24 March 2019 (UTC)