User:SPhotographer/textcase

Topic raised at FAC: the notes with calculations

At this article's FAC, I queried the extensive footnotes. I should have made clear that I'm not referring to footnote 1, but to notes 2 through 7. Here is the initial interchange with the nominator:

• Now. Those notes. They are unsourced, arcane, looooong, look to this untrained eye to be original research and my initial view is that they should not be there. I am open to arguments as to why I am wrong :-) hamiltonstone (talk) 13:42, 5 September 2012 (UTC)

Ya, they're a little much, I have to agree. Let me start with the short answer, then we can look at each note separately. Point #1: I don't think the notes constitute original research since they are all routine calculations–high-school math, and a few formulas from Wikipedia. Point #2: Betelgeuse, when you start to research it, is a confusing star. There is a ton of information out there, much of it does not agree, a lot of it is dated, and research is proceeding so rapidly that even the experts don't agree. So the intent from the beginning was not to give the reader a "fait-accompli" and thus add to the confusion, but rather a rich mosaic of the important points, so they could make sense of it all. In a few instances, notes were needed. Point #3: I, as a non-scientist, wanted to understand–hence the use of analogies like Wembley Stadium, the mango and noctilucent clouds. If you tell me that a star has a density of 1.576 × 10⁻⁵ kg/m³, I have no idea what that means - hence the use of analogy. Unfortunately, scientists seldom if ever use such analogies, so there are no references. The best you can do is high-school math; that way the reader can follow your logic, if they want to. Now for each note:

Note 1. Apparent Size Table. In trying to understand all the conflicting information on the star's diameter, I created a spreadsheet. Once done, I thought "Hmmm! Maybe readers will find this useful." If you think it's overkill, we can just delete it.

Note 2. Betelgeuse Radius. This is a really valuable note. Right now, there are many articles on the web saying that Betelgeuse has a radius equal to the Jovian orbit of 5.5 AU. See APOD 2010. If Perrin's hypothesis is right however, we might see 4.3 AU real soon. So at least with this note, the reader can understand why such a vast difference.

Note 3. Speed of contraction. I just used some routine math to get a sense of how fast a photosphere could contract, given what was observed. We can omit this information altogether. It's not that critical.

Note 4. Luminosity. Every article you read on Betelgeuse "out there" quotes a different luminosity figure. To me, that's confusing. So that's why I provide the standard luminosity formula so readers can make sense of the vast divergences in the articles they read.

Note 5. The mango analogy. This is my favorite one. I just love visualizing myself inside of Wembley Stadium and imagining the Earth as a one-millimeter Pearl. It's experiential, and here's the math to back it up.

Note 6. Betelgeuse Volume reduction. Once again, I just wanted to understand what it meant if Betelgeuse's radius contracted, what that would mean in terms of volume. Wow! 680 million suns in 15 years. That's mind boggling!

Note 7. Noctilucent cloud analogy. Finally, just another attempt to take something esoteric like atmospheric density and relate it to something on Earth.--Sadalsuud (talk) 19:47, 7 September 2012 (UTC)

While I appreciate and support the editors' objective of relating the article content to easily understood concepts, we can only carry this so far, if the reliable sources fail to do so. I want to make some suggestions.

• In some cases, I agree that the notes constitute lengthy, but nevertheless routine calculations. However, as routine calculations, they do not need to appear in the article. I suggest that those calculations used to generate particular results can be included up in some sort of collapsed box at the top of the article talk page, if anyone wants to check them, rather than cluttering up the article space. I think the calculations in notes 3, 5 and 6 meet this threshold. Despite looking more complex, the calculations in note 2 represent simply multiplications or divisions, and also are routine. However, they do rely on a formula, and that concerns me a bit. Which brings me to my second point:
• In other cases, I think the "routine calculation" argument is too much of a stretch. I do not think the bar for 'routine' is "high-school math, and a few formulas from Wikipedia" (quoting Sadalsuud above). I think it is lower than that. The policy page says "Basic arithmetic, such as adding numbers, converting units, or calculating a person's age, is allowed provided there is consensus among editors that the calculation is an obvious, correct, and meaningful reflection of the sources". I am not convinced the use of formulas, particular that in note 4 (which BTW needs a reliable source itself), can qualify. In the case of note 4, the calculations are used to support the following claim: "Nevertheless, since Betelgeuse is a pulsating variable star, there are times where the star's luminosity could theoretically exceed 200,000L☉". That is the kind of fact for which I think a straight-out reference should be relied upon, rather than a complex calculation by our own editors. If no source includes that figure in its range of luminosity estimates, there may be a reason, and the sources are better placed to consider that than we are, so that sentence may have to be dropped.
• Note 7 presents a slightly different issue. The initial sets of calculations are routine, but they are then plugged into a "model" of the earth's atmosphere to come up with the altitude estimate. I think that is going too far (and would need references in any case). In any case, I think it is unnecessary. I suggest the note and the analogy, while colourful and interesting, be abandoned in favour of the plain English comparison made by the author of one of the two sources already cited: "Such star material has a density of less than one ten-thousandth the density of ordinary air" (AAVSO article).hamiltonstone (talk) 00:45, 9 September 2012 (UTC)

• I removed note 3 (Speed of contraction) - 1000km/hr isn't hugely unusual for celestial objects really Casliber (talk · contribs) 05:53, 9 September 2012 (UTC)
• I removed note 7 (Noctilucent cloud analogy) - I think readers can better visualise a "red-hot vacuum" much better than earth's mesosphere, which renders the latter comparison unnecessary. Casliber (talk · contribs) 05:58, 9 September 2012 (UTC)

• <scratches head> actually, my immediate reaction to "red hot vacuum" was 'huh? but it's a vacuum...' I liked the "one ten-thousandth the density of ordinary air" - that was the comparison that made sense to me. But whatever... :-) hamiltonstone (talk) 06:23, 9 September 2012 (UTC)

• Interesting - I guess "vacuum" to me is a more vivid and immediate image...and I assume that all vacuums are relative and not absolute in their vacuum-ness.... Casliber (talk · contribs) 08:42, 9 September 2012 (UTC)

• Both analogies, I believe, are important. The "red-hot vacuum" analogy comes from Burnham's Celestial Handbook, which I understand is a "classic" in astronomy. The problem with the analogy however, is most people understand the word "vacumm" to mean "absolutely nothing". So the analogy is confusing for most. It was initially for me. Also, the Wembley Stadium picture has this in the caption: "...while the air in the stadium is actually far more dense than the star itself." So a reference to air is important. It's the thing we can relate to the most on this planet.--Sadalsuud (talk) 10:41, 9 September 2012 (UTC)

Elegant solution?

• In thinking about this issue in the last 2 days, a thought occurred to me that might be the most elegant solution. Why not siphon off this information to other articles and blue link from this article? Let me give you one example–Note #4 on Luminosity. That formula actually comes from the Luminosity article. I've put a lot of work into that article recently, and what I realize now is that Note 4 is not just about Betelgeuse, it's also about the challenges that astronomers face with every star. So this discussion would be very appropriate in the luminosity article itself, and if it is set up with its own heading could be easily blue linked from the Betelgeuse article. What do you think?--Sadalsuud (talk) 07:50, 9 September 2012 (UTC)

• Sounds like a good idea Casliber (talk · contribs) 08:44, 9 September 2012 (UTC)

• OK. Note 4 (now note 3 following recent deletion) is easy to move, as already mentioned. In fact, by moving it to the Luminosity article, a theoretical discussion of "potential luminosities" would be appropriate as it would highlight the challenges that astronomers face and thereby enhance the reader's understanding of the concept of luminosity.

Note 2 could probably be made to fit in the Angular diameter article, although that article will need some work, so the Betelgeuse calculations don't look completely out of place. Like Note 4, the formulas used for Note 2 come from the Angular diameter article. So all we are doing is taking information already in the article and giving them a practical application.

Regarding Notes 5&6 (now 4&5 following deletion), I like the idea of a "collapsed box", but don't know how to do that in Wikipedia. Casliber, do you? If so, maybe you can focus on Notes 5&6 and I'll focus on Notes 2&4. Sound like a plan?--Sadalsuud (talk) 11:11, 9 September 2012 (UTC)

• Both the radius and luminosity notes have now been deleted in the Betelgeuse article and recreated in the Luminosity article. A simple ref has been created in the Betelgeuse article that reads: "For detailed computations of stellar radius and implications relating to the star's luminosity, see the Computational challenges section in the Luminosity article". Any concerns here?--Sadalsuud (talk) 11:47, 15 September 2012 (UTC)

• I don't know how this is going to go with other editors, but it would certainly help if the relevant sections of the Luminosity article had citations, which are currently absent, including citations for the luminosity formulas in general (before one even gets to the "computational challenges" section). But I doubt this is going to be an important issue at the Betelgeuse FAC. Regards, hamiltonstone (talk) 11:51, 15 September 2012 (UTC)

• Thanks. I'll see what I can find. The article, of course, still needs a lot of work, but it's coming along. I tried inviting other editors into an improvement discussion on the Talk page, but so far no feedback.--Sadalsuud (talk) 12:23, 15 September 2012 (UTC)

• The formulas are now referenced with a web reference from Australia Telescope Outreach and Education, Australia's premier radio astronomy research group. Time permitting, we'll get the rest of the article polished up. It's my goal to take it to at least GA.--Sadalsuud (talk) 12:52, 15 September 2012 (UTC)

Collapsible content?

• there are a few ways of doing it. I have to find another Featured Article with one in to find what the Officially Sanctioned one is.... Casliber (talk · contribs) 21:27, 9 September 2012 (UTC)

• Alright, I've looked at Wikipedia:Manual_of_Style#Scrolling_lists_and_collapsible_content which suggests we could collapse notes 4&5...question is how do we want to do it. I've seen Help:Collapsing...do we want 4 and 5 to collapse individually, or the whole notes section to be collapsible or.....what? Tricky question. Casliber (talk · contribs) 14:57, 10 September 2012 (UTC)

• As an update, I have notes 4 and 5 in collapsible boxes now. I have some RL stuff to sort out, so tweak it at yer leisure :) Casliber (talk · contribs) 13:34, 13 September 2012 (UTC)

• As you'll see, I added short instructions to each note that read as follows: "For computations relating to Betelgeuse volume, click [show]". I think it helps. I could not find a way to edit the text in the box itself. Replacing "Extended Content" with "Betelgeuse volume calculations" would be best. Thoughts?--Sadalsuud (talk) 12:15, 15 September 2012 (UTC)

I think we're done for now, thank you for that. We'll see i9f any other reviewers weigh in. hamiltonstone (talk) 00:35, 14 September 2012 (UTC)

The size of betelgeuse

I'm not convinced that the text regarding the star's diameter is adequate, and as I've noted above and at FAC, the use of calculations and formulas makes me all the more nervous. I figure there's a reason that key journal articles choose not to convert angular diameters into object size. One of those reasons, of course, is the disagreement about how far away the star is. In any case, I wonder if the text can be improved.

• The article has this: "They also included a theoretical allowance for limb darkening yielding a diameter of 55.2 ± 0.5 mas—a figure which equates to a radius of roughly 5.5 AU (1,180 R☉), assuming a distance of 197.0 ± 45 pc.[note 2]" One can't have a single result ("roughly 5.5AU") when assuming a massive distance range (152 to 242pc). I know the next sentence addresses this, but it reads oddly. I admit I haven't yet come up with a concrete proposal to improve the text, though.
• This sentence "Nevertheless, given the angular error factor of ± 0.5 mas combined with a parallax error of ± 45 pc found in Harper's numbers, the photosphere's radius could actually be as small as 4.2 AU or as large as 6.9 AU" has a footnote, but that note is just a cross-reference to the calculation notes. I get the point being made, and I've no reason to doubt the calculations, but I'd be a lot happier if this sort of discussion was published in the literature somewhere - maybe a popular science astronomy article?
• The article has this: "This conclusion, if further corroborated, would suggest an average angular diameter for Betelgeuse closer to Perrin's estimate at 43.33 arcseconds, hence a stellar radius of about 4.3 AU (924R☉)[note 2] in lieu of the widely accepted Jovian orbit of 5.5 AU.[37][71]" I had a look at reference 37. I could find nothing that came close to the article text of "the widely accepted Jovian orbit of 5.5 AU", and no reference to Perrin's estimate. The NASA astronomy picture of the day reference uses the Jovian orbit reference, but that hardly constitutes "widely accepted". However, it does raise the question: how did NASA decide that radius? What was their source, and can we use it too, instead of relying on our own calculations?
• There is an additional minor issue that the heading reads "angular size", but the article goes beyond that, to 'actual' size estimates.hamiltonstone (talk) 23:30, 10 September 2012 (UTC)

• I'm rewriting this section, noting the above concerns. I hope to have something done in the next few days. As you have already surmised, the problem comes down to a lack of consensus on two issues: 1) distance and 2) angular diameter. I've googled magazine articles, but they were either vague or understandably non-committal: Astronomy Now, and Bad Astronomy, though Astronomy Magazine, APOD2010 as well as AAVSO were fairly explicit on the issue of the Jovian orbit (5.5AU)--Sadalsuud (talk) 21:21, 12 September 2012 (UTC)

• That's great that you found those sources talking about the diameter in terms of AUs / Jovian orbit. I'm a bit busy right now, but will keep an eye out and will be back soon. hamiltonstone (talk) 23:45, 12 September 2012 (UTC)

• Ok. I think most if not all the concerns have been addressed. Let me know. It will require a little tweeking here and there. There are some minor things I'd like to add, but for the most part it's done.

I also had to modify the Parallax section, incorporating the van Leeuwen data, that way teeing-up the discussion that follows in this section. I also debated what name would best describe the section while avoiding the ambiguity you highlighted. There were several I considered: 1) Stellar diameter, 2) Stellar disk, 3) Stellar size and 4) Angular size. In the end I decided on simply "Diameter". I prefer it over "Size" as the latter strikes me as too generic. "Diameter", implies both definitions of stellar size−angular diameter and radius (i.e. R_☉).--Sadalsuud (talk) 17:40, 14 September 2012 (UTC)

Also take a look at the last paragraph of the Approaching supernova section. There was a recent contribution from Credulity as to all the speculation regarding the "Supernova around the corner" prediction, which I've reworked a little, adding the Ravi article as a reference. Any concerns here?--Sadalsuud (talk) 06:29, 15 September 2012 (UTC)

Looks OK to me :-) hamiltonstone (talk) 08:42, 15 September 2012 (UTC)

Published references

I just got slapped for using an unpublished reference, albeit one that was already included as a reference in this article. But how about Wolfram Alpha? NASA and ESO press releases? Own calculations? APOD?!? You can't seriously think those are reliable sources of information? Lithopsian (talk) 19:31, 1 November 2012 (UTC)

Hang on, I just woke up and saw this. I'll take a look. I agree we should change Wolfram Alpha. Let me see.....Casliber (talk · contribs) 19:59, 1 November 2012 (UTC)

Most of the press releases are written with corroboration with the main researchers studying Betelgeuse...this will be interesting too. Casliber (talk · contribs) 01:00, 2 November 2012 (UTC)

Math styling

Not specific to this article, but prompted by a recent edit and reversion. The solar symbol can be represented by a unicode character or by a MathTEX circle with a dot in it. I find the math styling to be cumbersome and ugly. The font and spacing doesn't properly match the surrounding text which is jarring, it takes forever to appear on large articles so I quite often run across unrendered pieces of markup, and in some cases it doesn't render at all depending on browser settings. The unicode character. in this case, renders immediately and consistently with the rest of the text. Discuss :) Lithopsian (talk) 12:00, 6 November 2012 (UTC)

So you're saying you like this one? If so I think I do too....Casliber (talk · contribs) 12:59, 6 November 2012 (UTC)

Yes, I prefer it like so: M_☉. I'm interested because I made some edits recently to place the unicode sun symbol into some articles to replace repeated cumbersome text descriptions, and want to see if that is generally acceptable before I do any more. Lithopsian (talk) 14:14, 6 November 2012 (UTC)

My problem with using M_☉ is that it's unreadable, at least under Safari. The circle does not show up with a dot in the middle, it's a round thing. When zooming in to see individual pixels, it shows up with what looks like a triangle inside. Tarl.Neustaedter (talk) 19:57, 6 November 2012 (UTC)

Webkit support for high Unicode characters was always patchy but I thought they'd sorted it for the most part. Except on Android which still has a number of pretty bad problems. Lithopsian (talk) 11:25, 7 November 2012 (UTC)

Here are examples as they appear on my screen:-
Math images: http://www.nartowicz.webspace.virginmedia.com/modot.png
Unicode: http://www.nartowicz.webspace.virginmedia.com/unicode.png
— Preceding unsigned comment added by Lithopsian (talk • contribs) 11:50, 7 November 2012 (UTC)

- - -

Here are the equivalents as they appear on Safari under MacOS 10.8.2:
Math odot: http://tarl.net/solar-mass/odot.png
Unicode: http://tarl.net/solar-mass/unicode.png

Tarl.Neustaedter (talk) 00:28, 8 November 2012 (UTC)

Binary?

The article gives the misleading impression that one or more binary companions are likely. It references a paper that suggest some knots in the circumstellar material were other stars, but ignores the multiple searches that have failed to find any support for this. It also quotes a more recent paper as not ruling out the companion, giving the impression that it is still likely, when in fact that paper says it is "very unlikely" that the features observed represent another star. Lithopsian (talk) 14:45, 17 November 2012 (UTC)

I was wondering how it read to an outsider. When we wrote it, we wanted to give the impression (because it reflects the literature) that you expect above - i.e. one study found some interesting evidence, but no-one else has seen this and it appears highly doubtful, all things considered. However, you're the first one to suggest the emphasis reads differently, so I wonder whether we have to rejig it to make it plainer (that it is unlikely). Have you got an idea on a rephrase? Casliber (talk · contribs) 19:21, 17 November 2012 (UTC)

Section 4, Star System, the main one that discusses this, is perhaps OK in itself. There is a statement in the Properties section that Betelgeuse has no known companion so that is hardly raising expectations. But then there is that last sentence of the introductory section: "Possible stellar companions orbiting within this circumstellar nebula may also contribute to the star's enigmatic behavior." Given its prominence in the introduction and the fact that no researcher is seriously considering this as an option, this seems to me to generate a misleading impression of the likelihood that Betelgeuse is a multiple system. Lithopsian (talk) 20:11, 17 November 2012 (UTC)