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If the unit angstrom is named after a person, why isn't it always capitalized like Watt, Newton, Joule, etc?-- (talk) 16:30, 28 March 2008 (UTC)[reply]

The units you mention are not capitalised. They are spelled watt, newton and joule. Thunderbird2 (talk) 17:23, 28 March 2008 (UTC)[reply]

The use of the word "angstrom", with or without diacritics, should not be capitalized when referring to the unit anywhere in this article. The symbol has the capital Å but the word should use lower case. The article is inconsistent and (usually) wrong. (talk) 20:46, 5 February 2013 (UTC)[reply]



I have a question about the statement that the Angstrom is obsolete. The Angstrom is very much alive and well. I don't think you mean to say that it is no longer used, but that could be explained better. Do you mean that it changed when the meter changed? AndyofVermont 03:14, 11 April 2007 (UTC)[reply]

Pronunciation of Angstrom


How would you pronounce "angstrom" in Swedish? An IPA transcription might be useful. 05:19, 19 January 2006 (UTC)[reply]

It might be called for, that User:Jor explains more carefully how and why he thinks that the angstrom-symbol "is" different from the Swedish character Å. The symbol is chosen after the initital of the surname Ångström, as far as I understand, in the same way as W is chosen as the symbol for Watt after James Watt.

Please educate me!
--Ruhrjung 17:17, 26 Mar 2004 (UTC)

As it "might be called for", I will explain User:Ruhrjung that the Angstrom character resembles an Å but tends to be rendered more thinly and with a smaller circle above, just like the Watt W resembles a Latin W but is not identical to it. Perhaps User:Ruhrjung would like to check the Unicode standard? — Jor (Talk) 17:26, 26 Mar 2004 (UTC)
Tat is not a "Unicode standard" for writing these symbols. In fact, that section of Unicode is only included as an accomodation for interpreting things in some old non-Unicode code pages in certain East Asian languages, and it is not for current use in Unicode even in them. The proper symbol for the angstrom is indeed the Swedish letter Å. Gene Nygaard 01:18, 27 Jun 2005 (UTC)

The relevant standard ought not to be Unicode but something from ISO or some physisists' international organization.

To compare the rendering of angstrom-symbol and the Å-character, you could for instance see textbooks in physics in languages where the¨Å-character is domestic.
--Ruhrjung 17:36, 26 Mar 2004 (UTC)

Spelling and article name


Could anyone enlighten me how the Å-unit is written out? Some textbooks write "angstrom" others "angström" and some "ångström" (which should be correct according to the origin of the unit).
--Universalis 10:58, 31 Apr 2004 (UTC)

Well, "ångström" should be the most correct, considering that was the original surname Ångström. I guess angstrom would be acceptable if you are having problems with non-standard characters. Angström seems as a strange compromise for systems that could only handle umlauts...
The "angstrom" spelling is just as correct as "ampere", which is almost always written without an accent mark in English though it has one in French. There is, of course, no internationally standardized spelling for the spelled out words of any of the units (consider the "meter" and "metre" spellings in English, or "chilogrammo" in Italian); it is only the symbols for them which are standardized internationally. Gene Nygaard 01:18, 27 Jun 2005 (UTC)
To be pedantic, it isn't "just as correct", because "å" and "ö" are considered to be distinct letters in Swedish and not "a" and "o" with diacritical marks, which is the situation for "è" in French. Doesn't mean "angstrom" isn't perfectly acceptable though. --BluePlatypus 15:05, 18 March 2006 (UTC)[reply]
If I were to be pedantic about it, I'd come to the opposite conclusion and say that it is more correct to use diacritics such as the grave accent in ampère in English that it is to use non-English letters in English. Gene Nygaard 17:24, 18 March 2006 (UTC)[reply]
But if you want to use English characters, the 'right' thing to do would be to transliterate the letters (as in your surname), so "Aangstroem". --BluePlatypus 17:05, 20 March 2006 (UTC)[reply]
The distinction between "diacritics" and "different letters" is irrelevant. Yes, the names of the persons are written "Ampère" in French, "Volta" in Italian, and "Ångström" in Swedish; and they could be written "Ampere", "Volta", and "Aangstroem" in English. But those facts are totally irrelevant for how the units are named in English. Again, the units are not the persons.

I just converted the page to "angstrom", becuase that is the most common spelling of this unit in English. From WP:NAME, "Name your pages in English..." and "Use the most common name of a person or thing..." --Srleffler 22:59, 29 October 2006 (UTC)[reply]

And I moved it back for several reasons:
1. There was no discussion and/or concensus.
2. It is disrespectfull to Ångström to bastardize his name.
3. Ångström is much more internationally recognized than the bastardized version.
4. The diacritics indicate it is a foreign word, so they aid in pronunciation.

Cameron Nedland 23:54, 27 November 2006 (UTC)[reply]

1. And there was no discussion or consensus for your move back either
2. It is not a bastardization of his name.
3. It is disrespectful for you to not recognize the simple fact that it is quite proper and legitimate to use the English alphabet when writing in English. This blatant disrespect is exemplified not so much by your moving of the page, but rather by your totally improper removal of that spelling from the page.
4. Then, on top of everything else, you changed the indexing sort keys so that this article was missorted in its categories. Please go read Wikipedia:Categorization.
5. It is not a foreign word.
6. The Swedes don't use diacritics in sv:meter, unlike the French inventors do in fr:mètre, and the Swedes don't use diacritics in sv:ampere any more than the English do. In other words, the spelling of the words is determined in each language. What is international is the symbols for the units.
7. It is, in fact, best known in English under the quite legitimate and proper "angstrom" spelling. Gene Nygaard 03:09, 8 December 2006 (UTC)[reply]
  • Yes, the name of the scientist is properly spelled "Ångström". But the name of the unit (which is a different thing, not the same thing as the scientist) is almost always spelled "angstrom" in modern English texts (and even pronounnced as an English word). So the older/rarer spelling should be mentioned too, but the most common one must come first, and the article must be renamed accordingly. Jorge Stolfi (talk) 23:09, 8 June 2011 (UTC)[reply]
  • I just checked Webster's Encyclopedic Unabridged Dictionary of the English Language (2078pp, 1989). It lists Jonas Ångström and an Ångström crater on some planet; but for the unit, it gives "angstrom" ou "angstrom unit", says that the name may be capitalized --- and does not even mention the spelling with diacritics.
    The article definitely must be moved back to "angstrom". Jorge Stolfi (talk) 02:12, 9 June 2011 (UTmC)
aaaand in 2016 someone moved it back to Ångström, without discussion. — tooki (talk) 17:08, 9 February 2019 (UTC)[reply]
Thankfully someone moved it back. But while the spelling "ångström" should be mentioned, because there are many English papers that use it, the spelling "angstrom" mus be used in the rest of the article, as it is definitely the most common.

10-10 or 10-12?


Shouldn't it bother you guys that on this page it says that an angstrom is equal to both 10^-10 and 10^-12 meters? —Preceding unsigned comment added by (talkcontribs)

People who don't know what they are talking about bother me more. Maybe you have difficulty understanding what 100×10−12 means? Gene Nygaard 08:59, 8 December 2006 (UTC)[reply]

I mistook it for 10^-12 too, it would seem rather odd to state it as 100^-12, surely less confusion if it is stated the first way. Unless there is a specific reason for this.

I'll be another who got took in by the 100X10^-12 vs. 10^-10 confusion. The mixing of SI units and is much more cumbersome than relating everything to the meter. The information I was looking for was "How many angstroms in a meter", and I'd expect the answer to be the exponent, not an arbitrary multiple of 10^-10.

In addition, the 100 X 10^-9 mm is just confusing.

Zero light-years?


Why does it state that an angstrom is 0 LY? I know that its really really close to 0 when compared to LY, but it would be inaccurate to actually state it is 0 LY, since its base unit is defined in distance light travels in an ammount of time anyways.

Also, why does the article give the measurement in 100 times an amount? Why isn't it just a straight-up amount? It seems that this has already caused confusion, and I don't see a reason for it to be that way.

That was rediculous. Not zero but about 1.057×10−26 ly ... but, of course, such a conversion is not necessary on the page. JIMp talk·cont 03:05, 1 July 2011 (UTC)[reply]

Page moves


Please take any requested moves to WP:RM and avoid unilateral actions. Regards, Asteriontalk 12:08, 3 March 2007 (UTC)[reply]

By the way, I am not sure whether the tutorial on how to represent the symbol in computers is encyclopedic. Asteriontalk 12:10, 3 March 2007 (UTC)[reply]
It may be encyclopædic but it still doesn't belong here. JIMp talk·cont 03:06, 1 July 2011 (UTC)[reply]

Usage of official transliteration


Can we have a reference for "aangstroem" being the official transliteration? Can we also have a comment on whether this is just a transliteration of the name or of the unit as well, and whether it has any official status as the name of the unit? My understanding is that the unit is either "ångström" or "angstrom". I have never seen "aangstroem" used before. — Paul G 13:59, 10 April 2007 (UTC)[reply]

One thought on reality and "aangstroem": While I have no idea whatever where the single monolithic “official” policy for transliterating Swedish surnames into English comes from, the simple fact is that “angstrom” is the ubiquitous conventional English word for this unit of measure, not “aangstroem.” The way the article is written now is misleading in that suggests to the casual reader that the “official” word for the unit using the English alphabet is “aangstroem,” which, in reality, it is not. Right now it reads “An ångström or aangstroem (the official transliteration), or angstrom (symbol Å) . . . ” The word “aangstroem” should be deleted or put in a less misleading context. This is not the place for an uphill crusade to regularize transliteration of Swedish surnames when used for eponymous units of measure. In other words, it is really beside the point to even mention “aangstroem” if almost everyone uses “angstrom” instead of “aangstroem.” If “aangstroem” is mentioned, it must be in a way that shows its relative obscurity. Changing it to “An ångström (sometimes transliterated “aangstroem”), or angstrom (symbol Å) . . . ” would be less misleading, but it is still messy. I won't do it myself, because I don't care enough to fight over it.
According to the IUPAC Green book "Quantities, Units and Symbols in Physical Chemistry" (which is of course a subject where the use of this unit is ubiquitous, as compared to say Physics where nm is probably more common, as alluded to in the text) the recommendation seems to be for "ångström" for the unit (not angstrom or aangstroem or any other variation) so as far as I am concerned this should be the only variant used. The book can be seen in pdf format at http://www.iupac.org/publications/books/gbook/index.html for reference.- Azo bob 18:50, 20 July 2007 (UTC)[reply]
"Aangstroem" gets a mere 785 Google hits. The only "official" name for the unit as far as I know is "Ångström", and there is no such thing as an offical transliteration scheme for Swedish. Therefore I'm removing "aangstroem". EldKatt (Talk) 16:38, 7 August 2007 (UTC)[reply]
I checked the article out now because I googled `aangstroem` for the counts and was surprised Wikipedia was not there so I wanted to see if there was any mention of aangstroem. This is the multi-language way of writing umlauts + Å vowel in ASCII. Sure, there is no official body in the English language setting policies, only descriptivist guidelines, but German is a language with umlauts that had an official spelling reform and I would bet there is mention of it. I will grant that in English it causes many words like Boeing to be pronounced terribly, but this article really ought to be mentioned in one line that in Swedish the name Ångström would be rendered as Aangstroem in ASCII —same in Danish another language with Å and umlauts (ø=ö, y=ü) that also treats these as separate letters at the end of the alphabet. — Preceding unsigned comment added by (talk) 15:50, 18 February 2022 (UTC)[reply]

Proposed WikiProject


Right now the content related to the various articles relating to measurement seems to be rather indifferently handled. This is not good, because at least 45 or so are of a great deal of importance to Wikipedia, and are even regarded as Vital articles. On that basis, I am proposing a new project at Wikipedia:WikiProject Council/Proposals#Measurement to work with these articles, and the others that relate to the concepts of measurement. Any and all input in the proposed project, including indications of willingness to contribute to its work, would be greatly appreciated. Thank you for your attention. John Carter 20:50, 2 May 2007 (UTC)[reply]

Bizarre mixed engineering/scientific notation


In the infobox at the top right of the page, the angstrom is related to the meter with the strange relation "100E-12 m". This is, in my view, an unusual (to say the least) combination of engineering and scientific notation. The limitation to powers of multiples of three is only ever used with letter prefixes, such as in "100 pm". Unless someone comes forward to defend this entry, I will change it to "1E-10 m" in a day or so, and accordingly for the nanometer. 08:58, 11 September 2007 (UTC) (edited 09:01, 11 September 2007 (UTC))[reply]

You mention engineering notation, so you should be quite well aware that your statement "The limitation to powers of multiples of three is only ever used with letter prefixes, such as in "100 pm"" is false. In fact, engineering notation is rarely used in conjunction with a symbol containing a prefix, except maybe with kg since kilograms are the SI base unit. In other words, it might be either 100 E-12 m or 100×10−12 m using engineering notation, or 100 pm using prefixes, but not some combination such as 100×10−6 µm using both prefixes and engineering notation. Gene Nygaard (talk) 20:36, 6 February 2008 (UTC)[reply]

How common is the term micron?


The article claims that the non-standard term micron is commonly used. Is it? Is this old term not being replaced by the standard SI term micrometre (or same term spelt another way)? Heaps of Google hits, sure, but they mostly don't seem to refer to the unit. Is it common? Is it even still remembered? AHD says "No longer in technical use." JIMp talk·cont 08:54, 11 June 2008 (UTC)[reply]

AHD is wrong; micron is definitely in technical use (and it's not nonstandard, just non-SI; not the same thing at all). In my experience no one says micrometer, at least in EDA. SI fundamentalists make me tired. --Trovatore (talk) 03:05, 27 July 2008 (UTC)[reply]

... On the other hand, why do we need all this chat about the micrometre? We're talking about the ångström. JIMp talk·cont 09:09, 11 June 2008 (UTC)[reply]

... In fact the whole paragraph was redundant since the relationship with SI units were given in the intro. I've deleted it. JIMp talk·cont 19:14, 12 June 2008 (UTC)[reply]

Angstroms in a Parsec?


How many? (talk) 20:50, 2 September 2008 (UTC)[reply]

http://www.google.se/search?hl=sv&q=parsec+in+angstrom&btnG=Sök&meta= —Preceding unsigned comment added by (talk) 18:04, 9 October 2008 (UTC)[reply]

1 parsec ≈ 3.08568×1026 Å JIMp talk·cont 07:29, 25 June 2009 (UTC)[reply]

Pronunciation again


From the IPA given i gather that it should be pronounced something like ongstrem? But does any English speaker outside of Scandinavia actually say it like that or do they use normal English rules to say it - something like /æŋstrɒm/? Given the argument that it is an English word as well, wouldn't it be correct to say the name of the unit with English orthography when speaking English? If so, then couldn't it be wrong to say it with Swedish pronunciation when speaking English? However I would pronounce the surname with the correct Swedish sounds even when speaking English. (talk) 23:34, 25 April 2009 (UTC)[reply]

Requested move

The following discussion is an archived discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. No further edits should be made to this section.

The result of the move request was: page moved per discussion below. There wasn't exactly a consensus, but the arguments in opposition of the move were adequately addressed by those supporting it. - GTBacchus(talk) 19:21, 25 June 2011 (UTC)[reply]

ÅngströmAngstrom – This page was originally named "angstrom". It was renamed "Ångström" without discussion, a move that raised complaints by other editors (see above). In Webster's Encyclopedic Unabridged Dictionary of the English language, the only variants recorded are "angstrom" and "angstrom unit" (with optional capitalization of the "A"). The two entries for the spelling "Ångström" are the Swedish physicist and a planetary crater. (One may want to consider here also the authoritative opinion of the judges of the 27th annual Boone Winnebago Regional Spelling Bee.) A move to the former name is requested in order to comply with the general principles of English Wikipedia. Jorge Stolfi (talk) 04:17, 9 June 2011 (UTC)[reply]

  • Mild oppose: IUPAC says "ångström", and they are pretty authoritative in this field. A lot of people probably use "angstrom" but it appears to be technically correct as is. –CWenger (^@) 04:46, 9 June 2011 (UTC)[reply]
    • I checked the Green Book, and it does not seem to make any attempt to standardize the unit or its name. It only mentions the "ångström" in examples and in tables of conversion factors for non-standard units. The clearest reference to it occurs in a footnote on page 27, which says "Interatomic (internuclear) distances and vibrational displacements are commonly expressed in the non-SI unit ångström, where 1 Å = ×10−10 m = 0.1 nm = 100 pm. Å should not be used". On page 135 it even apologizes "The inclusion of non-SI units in these table should not be taken to imply that their use is to be encouraged". So the Green Book is not dictating the spelling of the unit (which would be outside IUPAC's mandate, BTW, even if it were a SI unit), but merely using what they think is the common or proper English spelling (which they probably got wrong). Or perhaps they used that spelling for political correctness towards their international readership. In summary, IUPAC is not (and does not pretend to be) an authority on this question. --Jorge Stolfi (talk) 16:12, 10 June 2011 (UTC)[reply]
  • Comment I've seen it as Ångstrom. (talk) 05:55, 9 June 2011 (UTC)[reply]
  • Neutral For what it's worth, BIPM suggests ångström. [1]. I see it both ways often enough... I don't think it really matters as long as both variants are listed in the first sentence of the article. --Steve (talk) 01:33, 10 June 2011 (UTC)[reply]
    • The relevant quote is again a footnote to a table of "Non-SI units accepted for use with the SI, and units based on fundamental constants", saying "The ångström is widely used by x-ray crystallographers and structural chemists because all chemical bonds lie in the range 1 to 3 ångströms. However it has no official sanction from the CIPM or the CGPM." Like the Green Book reference, this counts as a usage of the spelling "ångström", but hardly as a suggestion, much less an authoritative one.

Support Merriam Webster and Oxford both give "angstrom". Britannica and Columbia Encyclopedia both give "angstrom" for the unit, "Anders Jonas Ångström" for the scientist. For SI units, BIPM and IUPAC are authorities to consider alongside the dictionaries and encyclopedias. But this isn't an SI unit, so there is no reason to refer to them at all. Kauffner (talk) 12:47, 15 June 2011 (UTC)[reply]

Support. The article lead currently reads the unit's name is almost always spelled without diacritics in modern English texts, with a citation (Websters, 1989, also quoted above), it has said this for a while now [2] and this claim doesn't seem to be challenged above, what is being argued instead is what should be used. Wikipedia policy is to use what is being used. Andrewa (talk) 15:21, 17 June 2011 (UTC)[reply]

Oppose The unit is named ångström after Anders Jonas Ångström. It's symbol is Å. The only reason you see "angstrom" is because most of those who write in English don't know how to type å or ö on a US English keyboard. It's the same reason you often see Schrodinger instead of Schrödinger or its proper diacritic-less version, Schroedinger. BIPM and IUPAC trumps anything Merriam Webster or Oxford has to say about it. Headbomb {talk / contribs / physics / books} 03:38, 19 June 2011 (UTC)[reply]

The volt is named after Alessandro Volta, the farad after Michael Faraday, and the ampere after André-Marie Ampère, for that matter. A. di M.plédréachtaí 21:45, 23 June 2011 (UTC)[reply]

Oppose The IUPAC gold book describes the unit as "ångström" and the symbol is Å. --Andreas (talk) 00:52, 21 June 2011 (UTC)[reply]

Support per Andrewa. BTW, the BIMP says other provably false stuff about English, e.g. that the tonne is commonly called metric ton in English-speaking countries (isn't Britain one?).A. di M.plédréachtaí 21:51, 23 June 2011 (UTC)[reply]

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page. No further edits should be made to this section.

Displaying lower case title


Although it is wikistandard to upper case the first letter of a title, in this situation the reader may wonder which is correct usage. To display the title in lower clarifies this issue. I note that that lower casing the title itself was proposed in the recently approved RM. This not technically possible, but I did modify the display appropriately. Kauffner (talk) 14:59, 1 July 2011 (UTC)[reply]

How does angstrom differ from ampere, kelvin, palaeontology or bicycle, none of which have the title displayed in lowercase? As for “reader[s who] wonder which is correct usage”, the first sentence after the hatnote starts with “The angstrom”., duh. I'm reverting that. A. di M.plédréachtaí 15:27, 1 July 2011 (UTC)[reply]

Template for the symbol?


Is there a template for inserting this symbol into articles? I'm seeing some variation with how its being depicted. Thanks.DavidRF (talk) 18:39, 19 November 2012 (UTC)[reply]

Not that I'm aware of. It's OK imho to have multiple variations as long as they all look OK. Let me try:
  • Regular character - Å
  • Math mode -
Yikes, the math mode one is pretty bad. It shouldn't be italics. (It's not wikimedia's fault, this is what LaTeX always does.) There are a bunch of suggestions for a prettier angstrom sign here, but none of them work. I just tried <math>\mbox{\normalfont\AA}</math>, <math>\text{\AA}</math>, <math>\angstrom</math>, <math>\textup{\AA}</math>,, and others, but none of them parse.
Aha! Found one: <math>\text{Å}</math> --> , a good-looking angstrom sign in math mode.
Actually this is very strange. It seems to work on some wikimedia servers but not others. For example,
<math>\lambda = \sqrt{(4\,\text{Å}) \cdot \ell}</math> --> is working during some page previews but not others...
I think the next step would be to raise this issue at Wikipedia:Village pump (technical)...
So all that stuff is about the ugliness of math-mode angstrom sign. Is that the issue you're talking about? Or are there other issues too? --Steve (talk) 16:48, 20 November 2012 (UTC)[reply]
Inline text should use U+00C5 Å LATIN CAPITAL LETTER A WITH RING ABOVE (&Aring;, &angst;). -DePiep (talk) 16:54, 20 November 2012 (UTC)[reply]
DePiep - how about "Click the button in the wiki editing toolbox to insert a special character ... open the Latin menu ... click on the one that looks like an angstrom sign." Is that OK advice for how to insert the angstrom sign in inline text?
Have you ever seen anyone (incorrectly) use any other characters for the angstrom sign, besides the one that you're suggesting? --Steve (talk) 22:25, 20 November 2012 (UTC)[reply]
Yes, that produces the same character, the correct character to be used. I was answering the OP: is there a template? - my answer: no, we don't have templates for regular characters. And: it can be entered by HTML character ID, which is convenient for most keyboards. In general, outside of math and graphics, so in regular inline text, the font is preferred, not a graph. The question was not about which character is to be used, as you write, but how to produce it. -DePiep (talk) 09:55, 21 November 2012 (UTC)[reply]
It was me that asked the original question. Its a non-ASCII symbol and there are at least two Unicode characters for it -- Å Å -- which don't render same on different browsers, fonts, etc. Additionally, I saw a page where the symbol looked a bit more funnier than that and edited the page and saw that the raw non-ASCII character had just been pasted in. Seeing the two unicode possibilities, I didn't know how to fix it. (Unfortunately, I can't find that page, now). In the music pages that I frequent, they have templates for commonly used non-ascii characters. We're supposed to use template:sharp () or or music:template|sharp () over the raw non-ascii character (♯) and certainly never use the nearest ascii approximate pound/hash (#) -- so I thought there might be something similar here. But, if you've never had the need here and get away with just pasting in the non-ASCII symbol from somewhere, then I'll just do that.DavidRF (talk) 19:39, 21 November 2012 (UTC)[reply]
Good points. So there is also U+212B ANGSTROM SIGN (Letterlike Symbols) (next to U+00C5 Å LATIN CAPITAL LETTER A WITH RING ABOVE (&Aring;, &angst; · Latin-1 supplement; or 'extended')). Unicode says: "preferred representation is 00C5" [3], I think we should follow that. The music template is nice indeed, but there are other editors who do not like any character producing template. At least this symbol is also at hand in the drop down box (music is not). -DePiep (talk) 22:24, 21 November 2012 (UTC)[reply]
Oh, the special character drop-down box. That's the obvious solution which had somehow escaped me. I'll use that. Thatnks.DavidRF (talk) 14:20, 22 November 2012 (UTC)[reply]

Meaning of the name


As a Swedish speaker, I find the name slightly curious. Many common Swedish family names have the component "ström" (Bergström, Strömberg, etc; see also Swedish name) but "Ång-" is a weird one. I would understand it to refer to steam, but perhaps there is a dialectal or regional word root with a different meaning? As such, the name could be translated into "steam stream". I guess this piece of trivia is not fit for the article text, but if you are reading this, enjoy (-:-- era (Talk | History) 10:50, 17 December 2012 (UTC)[reply]

I've found this strange as well. I looked into it a little and it turns out Ångström's father and uncle, who were the first to use the name, were born in Ångebyn, Medelpad, just outside today's Ånge (and named after Ångan, a tributary to river Ljungan). (talk) 07:07, 5 June 2015 (UTC)[reply]



There is more to be said than just how to spell the name or the unit. Ångström was a reputable scientist and there is more to tell. For instance, in order to perform the accurate measurements he ordered a copy of the original meter bar from Paris. The problem was that the copy was some one cm too short (or too long, can't remember), introducing a systematic error in all measurements. This resulted in University of Uppsalas reputation being questioned. This was considered a very problematic back then for a university in operation since 1477. Several results not named after him were first obtained by him, for instance, (at least one of) Kirchoff's three laws. I'm afraid I don't have references, but this is what I've been told. The meter bar should still be there at the department of Physics and Astronomy. YohanN7 (talk) 13:49, 28 April 2014 (UTC)[reply]

Bravo! I confess, I didn't believe you at all at first, because 19th-century metrologists worked to much smaller errors than one part in 100. But you're broadly right. The fine details are that Ångström was using a bar already held in Uppsala but had it checked against a Paris bar that was itself checked against the primary standard. Good idea - it was a little short. But the eminent metrologist who checked it reported a much greater error - I haven't tried to find out if his reasons for doing so were questioned. I've added a sentence and a reference to the article. And now, exhausted from all that hard work, I'll leave it to you to add the Kirchoff's laws material to Anders Jonas Ångström - WP:SOFIXIT! :) NebY (talk) 16:59, 28 April 2014 (UTC)[reply]
Your edit looks very good. I'm afraid that all I have is (obviously!) vague and fading recollections of physics lectures in Uppsala. YohanN7 (talk) 16:06, 1 May 2014 (UTC)[reply]
I found a picture (of a painting), in the Swedish Wikipedia, and put it into the article. (I might be able to get my hands on a real photography as well ,not sure.) I also found out that Kirchoff's law of thermal radiation was discovered and published in 1852 by Ångström. We can thus let Kirchoff keep all of his so-called three laws, which I now believe are separate results, on his own. But being completely exhausted from putting in the image, I better rest a few days. YohanN7 (talk) 19:15, 3 May 2014 (UTC)[reply]
Grand! I've put the infobox at the top - I think it takes priority. Good to see your idea of resting for a few days is to cite Gödel. :) NebY (talk) 19:40, 5 May 2014 (UTC)[reply]
I now put in the Absorption law of Ångström. I think I shall have to lie down for a moment or two. YohanN7 (talk) 15:36, 8 May 2014 (UTC)[reply]

Corrupted "[Edit]" Tag


The [Edit] tag on each paragraph is in the big title font and doesn't have the usual square brackets. I have no idea how to fix this. (talk) —Preceding undated comment added 21:38, 5 March 2016 (UTC)[reply]

That was strange. But it seems OK now - maybe just a server cache problem. NebY (talk) 23:31, 5 March 2016 (UTC)[reply]

Assessment comment


The comment(s) below were originally left at Talk:Angstrom/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

In the History section, I just changed "length" to "wavelength"

Will also change "acuity" to something like "sensitivity" since acuity refers to spatial (angular) discrimination independent of frequency.

The assertion that the Angstrom was originally defined independently of the meter (but equal to 10^-10 m) would be more useful if augmented by an explanation of how it *was* defined.

Substituted at 05:20, 13 May 2016 (UTC)

Relation to SI


The Ångström, like many other traditional units of measurement, has been deprecated by the SI in favor of standardized SI units, while still remaining in widespread use. Crystallographers seem to prefer Ångströms, while a sizable fraction of spectroscopists have switched to nanometers, and nanotechnologists prefer the SI unit. Following the general practice of other Wikipedia articles, I have noted in the introduction that it is a non-SI unit, and given its equivalent in SI units, in this case as 0.1 nanometer. The cgs units erg and Gauss (unit), as well as the BTU and Curie (unit) are other articles illustrating this practice. The Ångström has an interesting history that is explained in the body of the article, including times when it was more accurate than the meter. The Calorie is more complicated, as there have been several different versions in use, with different values.CharlesHBennett (talk) 13:14, 20 August 2016 (UTC)[reply]

Saying that this or another unit are deprecated is rather silly. Units are lie clothing. They should suit the occasion. For instance, when doing EM theory in a manifestly Lorentz-invariant manner, Gaussian units are much preferred. SI units are fine as a means of standardization, but they aren't always optimal. The Ångström has the right size to be practical in atomic physics. YohanN7 (talk) 07:47, 22 August 2016 (UTC)[reply]
Having thought more about this, it is not at all your job, or Wikipedia's job to walk around deprecating things. Reverted again. Referring to a couple of other articles (edited by you?) as setting "standard" is a bit strange. YohanN7 (talk) 07:27, 23 August 2016 (UTC)[reply]
By the way, the nanometer is not a unit. The meter is, and an Ångström is 10−10 m. YohanN7 (talk) 07:30, 23 August 2016 (UTC)[reply]

In reply to YohanN7, explaining why I again undid his reversion: Not everyone agrees with the predominance of SI units, but the consensus of international authorities in charge of standardization is that they should be considered the principal or official standard, even while other units continue to be used. This is the technical meaning of "deprecate" in the context of standards, where the word means only this, without the derogatory connotation "deprecate" has in ordinary language. Certainly many people think that the movement to SI units in favor of more traditional ones is excessive or silly, but the fact remains that it is occurring, with the backing of internationally recognized standards bodies, in the case of the Ångström (as explained in detail further down in the article) and many other units as well, e.g. kJ in place of Calories on food labels, Grays in place of rads for ionizing radiation, etc. I have not edited any of these other articles on units of measurement, so the fact they generally begin by noting whether the unit is SI or non-SI (and then give the SI equivalent) is not my doing, and instead reflects existing Wikipedia practice.CharlesHBennett (talk) 03:15, 24 August 2016 (UTC)[reply]

If you can find a single text on QFT using SI units, I'd be surprised. YohanN7 (talk) 07:25, 24 August 2016 (UTC)[reply]
What you write here should go into the SI units article or talk page. It might be interesting there. This is an article about a historical unit, not about what international "authorities" feel, and need not have as the very first first description that is is not SI. That is just your immature POV and downright bad editing. YohanN7 (talk) 07:23, 24 August 2016 (UTC)[reply]

I agree that there are fields where non-SI units are used preponderantly (e.g. crystallography and organic chemistry, where the angstrom is arguably a more convenient sized unit than the nanometer), and others where SI units have made greater inroads, e.g. optical spectroscopy, where wavelengths (e.g. of the Fraunhofer lines) are often now specified in nanometers, but 30 years ago would have been specified in angstroms. I am not an expert in quantum field theory, but I would imagine that, because of the fundamental nature of the subject, dimensionless units would be most popular there, as they are in general relativity. In newer fields such as microelectronics manufacturing, which has developed mainly after the establishment of SI hegemony (as deprecators of the SI might call it), SI units are preponderant.16:00, 24 August 2016 (UTC)

We are probably misunderstanding each other. I am not advocating the angstrom. I usually prefer SI units myself, so there is no problem there. I don't either have a problem with mentioning in the article that the angstrom is not SI, even in the lead. It is not just the very first point for the lead to make. If you have a look over at Gaussian units, you will find a more balanced description of the relation between them and SI units (competitors with SI slowly winning). Then take the Furlong article. SI units are not mentioned first thing in the lead. Why should it be?
I propose instead that we have a standalone sentence, the last in the lead: The angstrom is not adopted as an SI unit. The main body of the article then details the relation. YohanN7 (talk) 09:37, 25 August 2016 (UTC)[reply]

1907 IAU definition of the Angstrom: Was it 6438.4696, or was it 6438.46963 (???)


I was wondering why I was coming up with 1553164.117 wavelengths of the cadmium red-line per 10^10 angstroms (the so-called "Cadmium meter", per the 1907 IAU definition given as 6438.46963), while virtually all internet searches were coming up with "1553164.13". Later, I managed to trace a change in the article from 6438.4696 to 6438.46963 in an unsourced one-character edit by, all the way back to 2008. I suspect that 6438.4696 (which yields 1553164.12459 per 10^10 (1907) angstroms) is correct (based on the printed publications which I have come across), and the error has since propagated to several other websites that have used Wikipedia as a reference. Should this ten-year-old edit be reverted, or not? DWIII (talk) 14:42, 3 September 2018 (UTC)[reply]

Angstrom vs ångström, again (sigh)


The name of the unit in English, for all practical purposes, is "angstrom", not "ångström". Just as the unit of current is "ampere" not "ampère", the unit of mag field is "oersted" not "Ørsted", and 1/1000 of a mm is a "micrometer", not a "μυκρόmeter".
Units of measurement are given names for one purpose only: to make scientific communication easier and more reliable. Not to stroke the ego of dead scientists, or of their countrymen. That the name is based on their names should already be enough of an honor: if they were not dead, they surely would be pleased even if we don't spell their names like the Swedes or Poles or Mongols do.
Demanding diacritics on the names of the units goes against that single purpose of unit names. Not only they are inconvenient, but having two names for a unit would be a source of totally pointless confusion (e.g. in searches). For the sake of productivity and comfort at work, in research or industry, we should not choose to use hard-to-type names, much less demand or suggest that others do.
As explained in the article, although the NIST and IBWM use the spelling "ångström", they do that only in the list of deprecated units. The vast majority of English texts use "angstrom"; and most English dictionaries (which are based on common usage) give that as the normal spelling, and may not even list "ångström" as a variant.
So please, please, let's not give the spelling "ångström" a legitimacy that it definitely does not have, and does not deserve. --Jorge Stolfi (talk) 06:45, 9 March 2019 (UTC)[reply]

Of course the names are given to honour the scientist too. Oxford says it spelled ångström too, therefore, it should be in the lead. The article was under the other title for three years without any complaints. Search machines knows how to convert from å to a or aa and so on, and the same "problem" occurs with meter vs. metre. Bring a source which says Ångström is outdated. Christian75 (talk) 14:25, 9 March 2019 (UTC)[reply]
I beg to differ: units are not given names to honor scientists. It is never "we need to honor حيان, let's name some unit after him", but rather "we need a good standard name for this unit, let's hear some suggestions".
As you can see further up in this talk page (ca. 2011), the article was created as "angstrom", moved to "ångström" without discussion, moved back to "angstrom" as a result of official discussion, and has been there for 8 years.
That discussion about the move cites plenty of evidence that the correct name of the unit in English is "angstrom", as recorded in authoritative dictionaries like Merriam-Webster, Collins, and even the Oxford Learners Dictionary; and that there is no authoritative support (or good reason) for giving "ångström" as a valid alternative name. Just as the unit names in English are "volt" not "volta", "farad" not "faraday", "oersted" not "ørsted", and "ampere", not "ampère". (By the way, even Italians call the unit "volt", not "volta".)
And, again, having two supposedly valid names for a unit goes counter the very purpose of giving standard names to units.
As for the OED, it is famous for collecting every meaning and spelling that has been used by someone since the 1600s...
--Jorge Stolfi (talk) 02:58, 10 March 2019 (UTC)[reply]

Angstrom vs ångström, again

Oersted is the same as Ørsted, oe is the same letter as ø in Danish. The thread you mention start with 'Some textbooks write "angstrom" others "angström" and some "ångström"'. Examples with more than one spelling are: roentgen/röntgen, metre/meter, - both are correct, Planck constant/Planck's constant, ... But it really doesn't matter what the spelling are for other words. Btw. I can give you a lots of sources saying units are named to honour the scientists, here is one [4]. Christian75 (talk) 14:40, 10 March 2019 (UTC)[reply]
If scientists had chosen to name the unit "orsted" in English, instead of "oersted", or "volta" instead of "volt", those would be their correct names. Same if they had chosen "aangstroem" instead of "angstrom". But they named the units "oersted", "volt", "angstrom" -- so those are their correct names. "Orsted" and "ørsted" are not valid alternative spellings: they are just wrong spellings.
You missed my point. Statues are created to honor scientists: they don't get set up by people saying "we need a statue here, let's hear suggestions for the subject". People say "we should set up statue to honor this guy, let's hear suggestions for where to put it.". But for unit names it is totally the other way around: scientists and technicians decide that they need a name for a unit of measurement, and they may eventually choose one that is based on the name of a scientist. But not always: see for example erg, metre, liter, candela, barn, mole, ...
"Meter" and "Metre" are not two alternative spellings of the unit. The first is the only correct spelling in American English (AE), while the second is the only correct spelling in British Engish (BE) -- two distinct (although very similar) languages. Some editors of scientific journals will even insist that the unit is spelled one way or the other, depending on where the journal is published -- no matter where the authors are from. It would not make sense to have a separate Wikipedia for each of these two languages, so Wikipedia works around that fact by the rule that the creator (or first substantial contributor) to an article gets to choose whether it will be written in AE or BE; but, either way, spellings must be consistent throughout the article -- no waffling between "metre" and "meter".
"Plank's constant" and "Plank constant" are not names of the unit in the sense that "angstrom" or "farad" are. They are English phrases that refer to "the constant that was defined by Planck". Thus it is correct, for example, to write "Ångström law of light scattering", or "Volta battery", or "Faraday cage"; and wrong to write "Angstrom law", "Volt battery" or "Farad cage" -- because those words are the names of the persons, not the names of the things. (Although "Angstrom law" is such a common mistake that it may be considered correct by now...)
All the best, --Jorge Stolfi (talk) 17:49, 10 March 2019 (UTC)[reply]
As you wrote yourself, "IBWM and the NIST spell it as ångström" - Therefore, it should be in the first line in the wp:lead. Christian75 (talk) 18:21, 10 March 2019 (UTC)[reply]
Well, that is no longer an argument since the 2019 edition does not mention the unit, in either spelling. --Jorge Stolfi (talk) 13:23, 21 November 2021 (UTC)[reply]
The four references used in the lead for ångstrøm still uses å. Christian75 (talk) 14:21, 21 November 2021 (UTC)[reply]

When was the unit actually defined / named?


When was the unit explicitly defined as a unit? Did Jonas define it as a unit, or did he just write "10−10 metre", "10−7 mm", or the like?
And when was it named "angstrom"? Obviously it was not Jonas who chose that name...
The article says "In 1892–1895, Albert A. Michelson defined the angstrom so that the red line of cadmium was equal to 6438.47 angstroms.[18]" However, the quoted text in [18] does not support that claim. Rather it seems that Michelson just established the length of the meter in terms of wavelength of specific spectral lines. Or did he define the angstrom elsewhere in the same paper? --Jorge Stolfi (talk) 08:00, 21 November 2021 (UTC)[reply]

According to Gross (2019) "Michelson invented an interferometer that substantially improved the precision of length measurements. This allowed him to define the ångström with respect to an atomic spectroscopic line, namely the red line of cadmium." Dondervogel 2 (talk) 08:46, 21 November 2021 (UTC)[reply]
Gross also says "[Jonas] introduced a unit length of 10−10 m, which was significant in accuracy without the need for fractional numbers." The second part of the sentence leaves me wondering whether the first part can be taken literally. (Measuring things in 10−10 meters is not more accurate than measuring them in 10−9 meters; it was only more convenient for Jonas in that case, as it avoided fractions).
So, did Jonas really propose a new unit of length for his tables, approximately 10−10 meters but in principle independent from the meter; or was his use of 10−10 meters just a typographically convenient ad-hoc choice? If the former, how did he call that unit? (Surely not "ångström"!)
Is Gross just interpreting Michelson's results as improving the definition of the angstrom, rather than just proposing a better definition for the meter?
Jonas died in 1874; was his name already being used for the unit when Michelson published his findings, only 18 years later? Did Michelson himself define the unit and name it "ångström", or were the concept and word defined by someone else, earlier or later? Was Jonas's son Knut, who worked in the same field as his father, involved in the naming somehow?
Maybe Michelson wrote "Ångström's unit" — which of course is not the same as "the ångström"?
The origin of the unit and of its name deserves be better clarified and documented. That quote from Michelson's article does not do that... --Jorge Stolfi (talk) 14:19, 21 November 2021 (UTC)[reply]
I searched the Michelson paper electronically for the string "Angstrom" and came up with nowt. This gives me the impression Michelson did not use that term. Dondervogel 2 (talk) 14:54, 21 November 2021 (UTC)[reply]
Thanks for the link!
I can sort of read French, enough to understand the paper (and enjoy the "literary" way science was reported back then!). I flipped through the whole paper and did not see any reference to Jonas or his unit.
What Michelson did was build an apparatus that, in a sequence of nine stages, would let him count the number of wavelengths of some monochromatic light between two parallel optical flats, with increasing separation ending with 1 meter. He did the experiment at the BIPM so he had access to the real meter standard bar. The results he obtained with that apparatus (page 85) was "the final conclusion of this work is that the fundamental unit of the Metric System is represented by the following numbers of wavelengths of the three cadmium radiations, ... red radiations: 1 m = 1'553'163.5 λR; green radiations: 1'996'249.7 λV; blue radiations: 2'083'372.1 λB."
I still don't see what was the connection between that and the angstrom, specifically.
All the best,--Jorge Stolfi (talk) 11:42, 22 November 2021 (UTC)[reply]
@Dondervogel 2: On the other hand, I found ONE reference to "angström" in This document, the proceedingd of the 7th General Conference on Weights and Measures, held in Paris in 1927.
By that time the metre was still defined as the distance between two scratches on that platinum-iridium bar (and would be for another 40 years), but the BIPM was still quite conscious of the work by Michelson (and Fabry and Perot after him), and were seriously considering replacing that definition with one based on wavelengths of spectral lines. In fact, they were already using Michelon's method, and thus (implicitly) the optical definition of the metre, to create secondary metre standards (quartz bars precisely 10 cm long) to be given to the standards bodies of member countries.<br;>On 1927-09-30, the commission discussed precisely that topic -- how to best redefine the metre in optical/spectral terms. In that session they use the angstrom without naming it, to specify spectral lines: "The experiments have led us to the five strongest lines of mercury (4358, 4916, 5461, 5770, 5791), to five lines chosen among those of neon (5852, 5882, ...". After a digression on details of the physical standards, the US delegate reports that the NBS urges the BIPM to adopt the spectral standard. The Japanese delegate concurs but asks for a moratorium while Prof Nagaoka in Tokyo finishes developing an improved cadmium vapor lamp. There is a request by a Mr. Kösters that the BIPM considers replacing the red line of cadmium by the yellow-green line of krypton. And then a Mr. Sears briefly objects that "the definition by angströms [sic] may threaten the Metric System, and it should be only temporary." But then "Mr. Guillaume observed that the point is not to establish a true relationship between the meter and the wavelengths, but only the metric value of the latter, which may be modified by future experiments.". And the session ends, with the invitation for members to visit the BIPM laboratories.
So that is an early reference for the unit, but it does not explain why and when it was defined.
What the article needs is dates and references for the statement, currently unsourced, that "Ångström's chart and table of wavelengths in the solar spectrum became widely used in solar physics, which adopted the unit and named it after him. It subsequently spread to the rest of astronomical spectroscopy, atomic spectroscopy, and subsequently to other sciences that deal with atomic-scale structures". That presumably is the real origin of the unit...
All the best, --Jorge Stolfi (talk) 21:38, 22 November 2021 (UTC)[reply]
I found this quote from the OED, "1906 Trans. Internat. Union Solar Research I. viii. 230 Resolutions concerning standards of Wave-length. The wave-length of a suitable spectroscopic line shall be taken as the primary standard of wave-length. The number which defines the wave-length of this line shall be fixed permanently and thereby define the unit in which all wave-lengths are to be measured. This unit shall differ as little as possible from 10−10 metres and be called the Ångström." Dondervogel 2 (talk) 22:32, 22 November 2021 (UTC)[reply]
Wonderful, thanks! --Jorge Stolfi (talk) 23:14, 22 November 2021 (UTC)[reply]

Unicode symbol


Does the Unicode Consortium specify why U+212B ANGSTROM SIGN is deprecated? It seems to me that it would be preferable to use an "angstrom sign" character when denoting angstroms vs. just an accented letter. Then there is some semantic meaning there for screen readers (read it as "25 angstrom" instead of "25 A") or parsers to find.

(I have the same question about other deprecations, e.g. U+00B5 MICRO SIGN and U+2126 OHM SIGN and U+212A KELVIN SIGN. Why strip the semantic meaning?) (talk) 18:35, 26 January 2023 (UTC)[reply]

Definition of meter/metre


In the history section, there is text "In 1960, the metre itself was redefined in spectroscopic terms". Should there not be additional text in that paragraph related to the current definition of the metre in terms of a fraction of the speed of light in a vacuum? The article, as written, gives the incorrect impression that the metre continues to be defined in spectroscopic terms. (talk) 16:07, 13 December 2023 (UTC)[reply]

Yes, that would be an improvement. Feel free to boldly add some clarifying text. Dondervogel 2 (talk) 16:40, 13 December 2023 (UTC)[reply]