Wikipedia:Articles for deletion/List of largest galaxies

The following discussion is an archived debate of the proposed deletion of the article below. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.

The result was redirect to List of galaxies. Sandstein 12:29, 11 June 2018 (UTC)[reply]

List of largest galaxies[edit]

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Was PRODded with concern "The values on this page are in large part incorrect, wildly inconsistent with one another, and do not conform to what an astronomer would use when referring to a galaxy's size." However, it was previously AFD'd in 2014, so I brought it to AfD.

Discussion at talk

There is already the List of galaxies article. This could go there. Plus, the size of galaxies are too uncertain, so such list will always be misleading. I'm too lazy to go find the deletion template but here is my request Tetra quark (talk) 19:05, 29 December 2014 (UTC)[reply]

Finally following up on this after 4 years, after being reminded of these problems due to a number of recent edits here.

The numbers given in many wikipedia articles for galaxy sizes are often not traceable to primary sources, may use very out of date cosmological parameters, were not produced from a consistent set of measurements (some come from NED's "apparent size", some are x-ray gas extent, some are radio extent, etc.), and almost none of them are what would be typically used by an astronomer to quote a galaxy's physical size (the half light radius in the optical/near-IR). Those incorrect wikipedia numbers get turned into this list, where the various objects at the top of the list exhibit all of the above problems. We're better off deleting this page and slowly correcting the individual galaxy pages or even just removing infobox statements about galaxy physical size entirely, than attempting what would be a very long process of primary source searching. And even searching through the primary literature is not a good approach: a consistent catalog of sizes should come from a single survey with a known surface brightness depth. This list has spawned hundreds of blogposts and webpages talking about the sizes of galaxies, so references to secondary sources cannot be used to correct it either.

Our best choice is to just delete it, to prevent further misinformation. - Parejkoj (talk) 19:54, 1 June 2018 (UTC)[reply]

The article was nominated for AfD in 2014 (and the deletion rationale is similar), so PROD is not applicable. I have brought it to AfD instead. –LaundryPizza03 (d c̄) 02:59, 3 June 2018 (UTC)[reply]

Of note is that this is the same concern as the previous AfD in December 2014. –LaundryPizza03 (d c̄) 03:11, 3 June 2018 (UTC)[reply]

Note: This discussion has been included in the list of Astronomy-related deletion discussions. MT Train^Talk 07:52, 3 June 2018 (UTC)[reply]

Note: This discussion has been included in the list of Lists-related deletion discussions. MT Train^Talk 07:52, 3 June 2018 (UTC)[reply]

Redirect to List of galaxies per WP:CFORK. Ajf773 (talk) 21:26, 3 June 2018 (UTC)[reply]
Keep Such list is commonly found, therefore it is valid under WP:LISTN. If the nominator has noticed any error, then the thing to do would be to fix it, not delete. Hzh (talk) 23:39, 3 June 2018 (UTC)[reply]

The errors are far too numerous and it is difficult to "get it right". For example, from a cursory examination, every single one of the first 10 items on the list violates one or more of my listed reasons, in addition to many not providing sources for their values. - Parejkoj (talk) 17:15, 7 June 2018 (UTC)[reply]

Redirect and merge (to List of galaxies) as being WP:OR and failing WP:V. The criteria given for the size of galaxies is not supported by a WP:RS and there is no way to verify whether the cited sources actually apply that criteria or not (since many don't mention it). I agree with the statements in the discussion copied from the talk page. 198.84.253.202 (talk) 01:54, 4 June 2018 (UTC)[reply]
Redirect to List of galaxies, books on largest galaxies, no, books on galaxies, lots. Coolabahapple (talk) 07:59, 4 June 2018 (UTC)[reply]
Keep or merge I used angular diameters and distances to determine the current size of these galaxies using http://www.wolframalpha.com (sorry to have included them without adding their determined sizes in their own articles). I think the best is to give a note how they have been calculated. So please do not delete this page. Thanks. ZaperaWiki44^{(✉/Contribs)} 10:48, 4 June 2018 (UTC)[reply]

So that means this is WP:OR??? 198.84.253.202 (talk) 11:47, 4 June 2018 (UTC)[reply]

Yes but we can use them anyway, but it is better to add a note that this has been done, useless there is already a reference that has already given a size. Since a calculated value will not appear in any reference, it may be deleted. Even User:Lithopsian isn't disagree with calculating radii from bolometric luminosities and effective temperatures for stars (or angular diameters and distances). So maybe for galaxies we could do the same thing. ZaperaWiki44^{(✉/Contribs)} 13:06, 4 June 2018 (UTC)[reply]

To misquote WP:NOTSOURCE, I am not a reliable source. However, I don't see anything wrong with making trivial calculations such as the radius of a star from (preferably compatible) luminosity and effective temperature values, when nothing else is available, and properly noted. However, doing the same for a galaxy seems to be stretching the concept of a trivial calculation: galaxies are not spherical, not remotely black body radiators, and effective temperatures are often not available or not meaningful in this context. While the problems with the list have been well-explained, it is still the sort of information people come to Wikipedia looking for. Lithopsian (talk) 19:56, 8 June 2018 (UTC)[reply]

Angular diameters from where, measured how? Distances from where, measured how? - Parejkoj (talk) 17:10, 7 June 2018 (UTC)[reply]

http://www.wolframalpha.com/input/?i=290+Mly*sin+%282.2+arcminutes%29. ZaperaWiki44^{(✉/Contribs)} 13:06, 8 June 2018 (UTC)[reply]

I know how to do the math. I'm asking where did you get the values from, and how were they measured? This is related to my deletion request: the values given on this page come from all over the place, with no consistency in what was measured. - Parejkoj (talk) 18:08, 8 June 2018 (UTC)[reply]

Redirect Headbomb {t · c · p · b} 03:02, 7 June 2018 (UTC)[reply]
Redirect to List of galaxies as per nom. Even if it may seem like a noteworthy list, size is a poor way to catagorize galaxies. - Spacepine (talk) 04:25, 8 June 2018 (UTC)[reply]
Redirect as per above. These are not "trivial calculations", hence the list consists almost entirely of OR and must contain incongruities with individual articles and published sources. --Elmidae (talk · contribs) 07:49, 11 June 2018 (UTC)[reply]

The above discussion is preserved as an archive of the debate. Please do not modify it. Subsequent comments should be made on the appropriate discussion page (such as the article's talk page or in a deletion review). No further edits should be made to this page.