Wikipedia talk:WikiProject Astronomy/Archive 15

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I put this list right here because for me this list has many issues:

For me this list is fascinating. One simple reader be extremely fascinated to look for it. However, when I saw it, it was a very poor list, with no references and poor details. For astronomers they will simply laugh at the list since galaxies don't have boundaries. Besides stars a huge dark matter halo is considered to be part of the galaxy. Not to mention that the Milky Way has a million light year dark matter halo. Plus, there are very few galaxies. To be honest I was planning to create the article and I was almost finished with my survey of BCGs of Abell clusters and now found 260 galaxies bigger than one million light years until Asyulus created this article with its current condition, with just 10 galaxies. And I was surprised that IC 1101 is at the top at 6 Mly. To be honest the largest I've found in the 260 I've surveyed is in Camelopardalis and is 15 Mly across. So I think this list must be expanded. More galaxies must be added, with reliable refs. Plus, let's put more precise definitions of the boundary of the galaxy. I need extra help. SkyFlubbler (talk) 03:41, 1 November 2014 (UTC)

The article lists values, these can be checked for in proper references. Those will explain if this is the virial radius or the diameter of luminous material. Have two separate lists on the article, one dealing with the virial radius, the other with the luminous material.

So the "easy" part should be finding references for the current stated values, that will fix the immediate problem of referencing.

The luminous size of galaxies have been used by astronomers to show that dark matter exists, so size is used. The virial radius is also used as a proxy for size

We could have a third list, for galaxy and its system of satellites out to the edge of its Hill sphere... for central galaxy to most distant satellite as the size of the system. (such as how the size of the Solar System is commonly understood, to be the edge of the Kuiper belt, or the last planet)

I would limit each list to the top 100 (yes, arbitrary, but not random, since this is a commonly used cut-off for lists in the world-at-large), to prevent from listing every galaxy known.

-- 67.70.35.44 (talk) 05:16, 1 November 2014 (UTC)

I think the best choice is the Hill sphere of a galaxy as the definition of its boundary. But it doesn't work for very distant galaxies. I can also use the definition of the boundary by the gravitational pull of a galaxy, via computing its mass through the mass to luminosity ratio and determining its gravity. Also, I may also use stellar density, such as the boundary where there is one star per ten parsec squared limit. The virial radius may be unprecise due to the inclination of a galaxy relative to our line of sight.

All those three are good, but let's also include their meanings as to not confuse the reader. Also, even if we limit the list to the top 100 that would still be incredibly huge. I may say only top 30 or 40 to prevent overexagerration.

A little note: I don't know how to search for references. Please help... SkyFlubbler (talk) 08:48, 1 November 2014 (UTC)

You could enter the value and the various galaxy names into http://scholar.google.com or http://books.google.com and find a paper/book that supports the value that meets

WP:RS -- 67.70.35.44 (talk

) 06:08, 7 November 2014 (UTC)

Oh, there should also be another section/list dealing with the angular diameter, as "largest" could mean how large it appears in the sky, and not its actual realspace dimensions. -- 67.70.35.44 (talk) 06:08, 7 November 2014 (UTC)

Anyone seen this? No, that's not an artist's simulation, that thing is a directly visualized protoplanetary disk!!! But we don't have an article on

Different star. The HL in this case is a catalog designation (Haro and Luyten), not a variable start designation, and 76 is the catalog number. Lithopsian (talk) 19:54, 6 November 2014 (UTC)

I can't find a catalogue designation, but I did find an article from 2011 in which scientists looked at HL Tauri (giving at least two references to the star and its position): http://iopscience.iop.org/0004-637X/741/1/3/article - so this seems to be a good candidate for an article. Primefac (talk) 20:04, 6 November 2014 (UTC)

I've found an older image on Commons of a jet from HH 151 (second image at right), which the caption says is feeding the formation of stars like HL Tau fed by HL Tau. (erm, oops!) So this is a really pretty story waiting to be told. Wnt (talk) 20:19, 6 November 2014 (UTC)

The reason that we don't have an article on HL Tau is that our coverage of notable astronomy topics is actually pretty shitty, and we're severely undermanned in the topic area, especially with many former regulars now retired or at low activity. Btw, the article should be created at the title

t • c

) 22:47, 6 November 2014 (UTC)

Stub's created. I'll flesh it out this weekend when I'm not about to go to bed. Primefac (talk) 23:37, 6 November 2014 (UTC)

Thanks! I actual edit-conflicted with you on the creation. :) Now I just hope what I added doesn't contain any... doozies. Wnt (talk) 00:25, 7 November 2014 (UTC)

So I'm a bit confused...some news articles say HL Tauri is associated with HH 150 [1], some say HH 151 [2]. Are they both associated with HL Tauri and the articles are just being dumb, or what? — Huntster (t @ c) 04:22, 7 November 2014 (UTC)

Sloppy reporting as usual, not least in the NASA press release. HL Tau is HH150. They are coincident within about an arcsecond and are at the same distance. There are three other HH objects within a few arcseconds, HH151-154. HH152 is another variable star, XZ Tau. HH151 a group of fainter knots within the nebulosity, and HH152 even fainter knots. In this image (apparently, since there is no scale or indication of the wavelengths imaged) HL Tau is the star with the bright jet, the bright jet is HH150, XZ Tau is the bright point-like object (although it has its own shells/shocks of nebulosity visible at other wavelengths, HH152), HH151 is the knots towards the bottom of the image, and HH153 is not visible off the top of the frame. Lithopsian (talk) 14:41, 7 November 2014 (UTC)

When all else fails, go for the peer-reviewed journal articles, they (more often than not) give the right answers! Primefac (talk) 19:22, 7 November 2014 (UTC)

Thank you for the clarification Lithopsian, that makes much more sense. So what stellar feature is HH 151 associated with...there's nothing on SIMBAD. Could it be the result of previous outburst activity from HL Tau? (yes, you can call me a dummy if I'm speaking absurdly) — Huntster (t @ c) 20:39, 7 November 2014 (UTC)

The caption for the second image talks about orange features where the jet strikes other interstellar material. A third image I've added above has the jet pointed to the left and the orange bits seem more obvious. Wnt (talk) 14:30, 8 November 2014 (UTC)

• OK, I've put this up for ITN. You can probably think of a better blurb though. Wnt (talk) 23:27, 7 November 2014 (UTC)

Three new lists of astronomical objects are created by an obviously well-intended user. Those are for nebulae, galaxies and planets. However, those lists have no references. Plus, so many wrong info are within it. I don't think that is right for those lists, especially to Wikipedia. I think all of the orders of objects on the list are original research.

But I think it is also my fault, since I created the largests for black holes and cosmic structures, which may "inspired" him. Anyway, I know you guys know this so much. Please add refs to those lists. SkyFlubbler (talk) 22:02, 5 November 2014 (UTC)

Could you link these lists? Sam Walton (talk) 22:07, 5 November 2014 (UTC)

Yes, it'd be helpful to know what lists you are talking about. And you can remind the person creating these lists about

WP:V -- 67.70.35.44 (talk

) 06:11, 6 November 2014 (UTC)

Oh okay. Here they are:

• List of largest galaxies
• List of largest planets
• List of largest known nebulae

But I think it would be useless even if I reminded him. I've already messaged him a lot in his talk and he's still unresponsive. I think it must be to the point that he will mention it greatly. SkyFlubbler (talk) 11:33, 6 November 2014 (UTC)w

@Asyulus: -- 67.70.35.44 (talk) 06:11, 7 November 2014 (UTC)

These do seem somewhat problematic, though I wouldn't be against the lists existing. They'd need to be much better than this though. Sam Walton (talk) 12:44, 6 November 2014 (UTC)

^What he said. They're looking better than when they were created, but still need a lot of work. The nebulae one and galaxies one are especially important, although the planet one not so much, because planets are less important in general than nebulae and galaxies.

t • c

) 22:50, 6 November 2014 (UTC)

I think these lists should eliminate the rank column, I don't think that is a supportable column. -- 67.70.35.44 (talk) 06:09, 7 November 2014 (UTC)

Both of you were absolutely right,

WP:OR

in their articles, and now it is so hard to correct the wrong info. So we must fix these lists ASAP.

These three lists are ugly ducklings, with the two being giant ones (the nebulae and galaxies list). This is extremely critical. If we prolong those info for longer it will spread on the Internet like a raging virus and will inform stupid people all over the wotld and will edit the articles on Wiki based on those info. Up until today someone still edit the list of largest known stars with W26 at the top.

To reduce the possible effect of this issue, we must not link it to many articles and fix it. SkyFlubbler (talk) 12:19, 7 November 2014 (UTC)

• WP:Risk disclaimer -- what is found on Wikipedia is not considered reliable, use at your own risk.
• WP:NOTFINISHED
  -- material found on Wikipedia is considered a work-in-progress, and not a completed work. The existence of the lists is not material to what the rest of the internet thinks.
• WP:Orphan -- information found on Wikipedia should be accessible.

WP:SOAPBOX

-- Wikipedia is not a platform to correct the internet.

The galaxy list is not the type of problem you are ascribing to it, since sizing of galaxies is frequently done in amateur astronomy, and has is done in professional astronomy. (such as how to describe hypercompact stellar systems, etc)

The problem is the nebulae list, where if you jumble all the types of nebulae together, the only things that would be listed would be Ly-α Blobs, as they are larger than galaxies. That needs to be converted to a largest nebulae by type table, and separate list tables for largest nebulae by type. I don't think that associations of nebulae should be listed at all, so someone (or when I get around to it, myself) should probably remove those.

I've already deleted the rankings from nebulae and planets, and will do so at galaxies soon. That's the only material that's of serious concern. Slap {{

listdev

}}s on and they will be shown to be incomplete.

-- 67.70.35.44 (talk) 05:42, 8 November 2014 (UTC)

No, for me all of the lists have problems. On the largest galaxies, as far as you are concerned, I've surveyed the Abell clusters and now found 260 galaxies bigger than 1 Mly. The problem is of all of the 260, only IC 1101 and the Phoenix Cluster BCG are listed. Two galaxies. Two of the 260 multimillion-light-year galaxies. And probably they are not all since I will start my SDSS check. How about the remaining 258? I think it's really not right. Plus, it's obvious that the one who created it is really just an amateur.

For the planets, there are only very few. Of all the thousand planets detected by the Kepler mission, those are only listed? Plus, as far as I'm concerned the largest planet is CT Chamaeleontis b which is not on the list.

The list of nebulae is not a really big problem as you expect; only more or less 50 LαBs are found so far, which is really not a huge number. And 30 of those are interconnected forming the 200 Mly Giant Concentration, making all of the 30 as a single nebula. Problem is we lack references, and those scientists do not give full reports. SkyFlubbler (talk) 04:07, 9 November 2014 (UTC)

Wikipedia is not Citizendium, verified credentials as an authority in the field is not required to write articles.

CT Chamaeleontis b is not a definitively planet, it's likely a brown dwarf.

The state of the lists is that they are under expansion. So, you found 260 galaxies bigger than 1Mly, congrats, now, we can restrict the list to the top 100 entries (plus the Milky Way for comparison) (to the limit of size accuracy, so tied entries get entered to extend past row 100) Many articles are longer than 100 rows, so "100" is not excessively long. As we improve the list, there will be entries that fall off the list. The same applies to planets (keeping Jupiter as a reference entry). An aphorism for you, even the longest journey begins with a single step. The single step was the creation of the articles themselves, now we need to take more steps on the route to better comprehensive coverage, and better accuracy.

The problem with the nebulae list is that it would rapidly become a list of only LαBs, if it isn't divided by type, if that were the case, it really should be called List of Lyman-alpha blobs, but if it should cover other types of nebulae, which it currently does, then we really need to separate them out by type with sublist tables, and have a starting table as a list of largest by type, instead of ending up with a table solely devoted to LABs.

-- 67.70.35.44 (talk) 05:54, 9 November 2014 (UTC)

Here's another GTRC. It's on

User:JonathanD has been posting huge textwalls of what looks like original research on Talk:Magnetospheric_eternally_collapsing_object, and adding a lot of OR content, linking MECOs to other topics. A little assistance would be appreciated. - Parejkoj (talk)

This article has suffered from FRINGE before, and was cut down to size before as well. -- 67.70.35.44 (talk) 06:43, 21 November 2014 (UTC)

Here's another GTRC. It's on

User:JonathanD has been posting huge textwalls of what looks like original research on Talk:Magnetospheric_eternally_collapsing_object, and adding a lot of OR content, linking MECOs to other topics. A little assistance would be appreciated. - Parejkoj (talk)

This article has suffered from FRINGE before, and was cut down to size before as well. -- 67.70.35.44 (talk) 06:43, 21 November 2014 (UTC)

I think the

Probably a good idea. Defining the largest of these things is always a rather messy thing. - Parejkoj (talk) 04:02, 22 November 2014 (UTC)

I think you should compile that list of 300 galaxies you said you had first. Since really, anything smaller than that list entry saying "300 galaxies" should be removed (except the Milky Way used for comparison). As you point out radio lobes, if a separate list article exists, a separate section of that article can be devoted to sorting by size of radio lobes. (Hence, my prior comments in a section further up this page, on the need to have separate sections split by what criterion is used to determine galaxy size) If we only have a list at the list of galaxies, it should be a table of largest galaxy by type or criterion (ie. largest galaxy by size of radio lobes, largest galaxy by virial radius, naked-eye visual apparent diameter, etc) A subarticle would actually be better for listing galaxies that are not the largest known of each type. Such a table would not actually involve merging anything from the separate list article.

I strongly oppose merging the nebulae into

List of nebulae

" is a list of lists and not an appropriate location to merge that list at this time. We would need to build a new list article in order to merge the largest list. As a compilation list of nebulae does not currently exist, it should not be merged into the list of lists.

-- 67.70.35.44 (talk) 05:54, 22 November 2014 (UTC)

FYI, there's a discussion at

For clarification, it's less about whether it should be deleted and more about whether it should be a feature image. Primefac (talk) 12:25, 23 November 2014 (UTC)

Now I just don't get how Markarian 177 was nominated for deletion by the fact that it was a big news this week. Here's a link:

http://www.sci-news.com/astronomy/science-mysterious-source-light-dwarf-galaxy-markarian177-02291.html

This is the first evidence of an SMBH outside a galaxy. It could provide the first evidence of recoil of gravitational waves. And it will be a sight for Hubble next year. So please tell me, why an object in worldwide news is being nominated for deletion? That is very foolish.

I amend to lift the deletion and since I have no more time, I also want for other greater experts to improve the article. SkyFlubbler (talk) 21:11, 23 November 2014 (UTC)

SkyFlubbler, the way it looks to me, an unreferenced, seemingly unremarkable article has been PRODed. This makes perfect sense in my mind. If you think the article can/should be improved, then simply remove the PROD (fortunately it's not an AfD so you can do it yourself). Someone in here might be able to improve it further. Primefac (talk) 21:30, 23 November 2014 (UTC)

Put simply: because the article is rubbish. That object should probably have a Wikipedia article, but it needs to follow the guidelines on content and referencing. If someone writes a decent-quality article, backed up by sources, then we should keep it. But a rubbish article on a notable topic doesn't help the encyclopaedia. Your efforts would be better spent on improving the Markarian 177 article, rather than complaining here. Modest Genius ^talk 13:34, 24 November 2014 (UTC)

A good article on the subject would be an asset to Wikipedia. However, when it was PRODded, there was no indication of any notability present in the article, and it simply looked like a generic unsourced article on a non-notable galaxy. Such an article does no good for the readers, by omitting the relevant information, and just presenting the galaxy as if it were a normal galaxy. Even now though, perhaps the SDSS source should be the object with the article, rather than the galaxy, since it is the SDSS source that seems notable.

t • c

) 16:22, 26 November 2014 (UTC)

Update: the

prodded. Modest Genius ^talk

16:38, 26 November 2014 (UTC)

There's a whole WikiProject just for the Moon?! I was not aware of that.

Wikipedia:WikiProject Solar System might be able to help. Modest Genius ^talk

15:57, 26 November 2014 (UTC)

• That also appears stagnant, so I don't think further notifications will do much to generate discussion. ColonialGrid (talk) 08:44, 27 November 2014 (UTC)

A WikiProject entirely dedicated to the Moon is probably way too small in scope to form an effective WikiProject. Merging it with WikiProject Solar System seems to be the best course of action here, to keep both active. Although it seems that WikiProject Solar System is also only semi-active too....

t • c

) 16:18, 26 November 2014 (UTC)

You posted a message only 3 days ago. You should not expect to get responses from Wikiprojects in less than a week. Many wikiprojects are only intermittantly active, so responses in less than a week for most wikiprojects is unlikely, as many editors are weekend warriors.

There are several related wikiprojects that would cover the Moon in relation to your posted question, WPMOON, WPAST, WPSOLAR, WPSPACEFLIGHT, WPGEOLOGY, WPMUSEUMS -- 67.70.35.44 (talk) 21:01, 26 November 2014 (UTC)

• Although I take your point, there are no responses to any posts, so I doubt many people are watching. Also, given the one week turnaround that DRs have at Commons, I would rather expedite consensus here (sorry if that sounds a little rushed, but I don't see my request as overly controversial, however, it would look unilateral and improper to make these changes in support of a DR at Commons without any discussion). ColonialGrid (talk) 08:44, 27 November 2014 (UTC)

FYI, Yorkernews (talk · contribs) has been inserting links to what seems to be his own blogspot (yorkerpress.blogspot) into an astronomy article multiple times. This might need tracking. -- 67.70.35.44 (talk) 21:05, 26 November 2014 (UTC)

(S)he seems to have stopped now, but please do let somebody know if it resumes.

t • c

) 20:58, 28 November 2014 (UTC)

I noticed this "Nature makes all articles free to view" which allows those that are subscribed to give a read-only PDF to people who are not subscribed. This should be helpful with the paywalled Nature papers that articles use for references, as the free-access PDF can be used as the URL link -- 67.70.35.44 (talk) 14:14, 2 December 2014 (UTC)

Incidentally, does anyone know how to use http://libgen.org that one of the commentators mentioned as an alternate? -- 67.70.35.44 (talk) 14:14, 2 December 2014 (UTC)

There has been a discussion at Talk:Earth about whether or not to use the definite article when talking about planet Earth. That discussion has seen remarkably little input from people listed in this WikiProject. Anyone interested in chiming in? --JorisvS (talk) 12:18, 3 December 2014 (UTC)

Hi, this is to let you know that we've launched WikiProject Wikidata for research in order to stimulate a closer interaction between Wikidata and research, both on a technical and a community level. As a first activity, we are drafting a research proposal on the matter (cf. blog post). Your thoughts on and contributions to that would be most welcome! Thanks, -- Daniel Mietchen (talk) 02:11, 9 December 2014 (UTC)

I think

I'm still waiting on SkyFlubber to provide that list of 300 galaxies he said that he's compiled up, to fix this article up. I wonder why he hasn't ever given any information about that list he said he had. -- 67.70.35.44 (talk) 05:55, 12 December 2014 (UTC)

I was wondering if I could get some comments on the Nibiru article and the section dealing with Nancy Lieder putting down her 18 month old puppy. -- Kheider (talk) 21:25, 14 December 2014 (UTC)

The List of most massive black holes is what I'm working right now. But it's very small, and has few entries. Of all the 200,000 quasars known, plus some other giant galaxies, only those are in the list. The majority of black holes above 1 billion M_☉ is in quasars. For instance, a hoax about a 73 billion M_☉ in a very luminous quasar in the far universe.

What should I do with the list? Can it be expanded, or just state it's incomplete? SkyFlubbler (talk) 09:40, 15 December 2014 (UTC)

I've tagged it as an incomplete list for now. However, unlike the galaxies list, this one doesn't seem to far removed from the correct order. However, if the 73 billion black hole is a hoax, why do you bring it up?

t • c

) 16:33, 15 December 2014 (UTC)

Here is a link to the sirius B article with no redirect: https://en.wikipedia.org/w/index.php?title=Sirius_B&redirect=no

We're discussing this on the Sirius talk page Cas Liber (talk · contribs) 19:58, 17 December 2014 (UTC)

Is there a list of all the ~35,700 pages WikiProject Astronomy cleanup listing looks at? Or a unique list of articles in Category:Astronomy? Using {{Category tree all}} is an endless task. Thanks!   ~ Tom.Reding (talk|contribs|dgaf) 23:36, 16 December 2014 (UTC)

We have a manually-maintained list of all stars

t • c

) 00:43, 17 December 2014 (UTC)

Thank you, I'm sure those will come in handy. Yeah, I'm surprised that's something not easily available or not continuously updated somewhere. However... I did some more searching and found an option in AWB to make a list from any category, recursively. Increasing depth, starting from 1 gave 1,908 uniques, 2 = 12,213, 3 = 45,951, 4 = 49,436, 5 = 58,160, so I think that covers it... I put the largest list in my namespace:

User:Tom.Reding/Pages in Category:Astronomy in case anyone else comes here looking for something like this. (The page is 1.12 MB)   ~ Tom.Reding (talk|contribs|dgaf

) 14:22, 17 December 2014 (UTC)

Wow, that could be a really useful list for a lot of things! Mind if I copy the list to either project space or my own userspace and wikilink each term, so I can check related changes since Dispenser's WikiProject watchlist is down?

t • c

) 19:53, 17 December 2014 (UTC)

Sure, go nuts. You can wikilink them on my page too.   ~ Tom.Reding (talk|contribs|dgaf) 20:07, 17 December 2014 (UTC)

Ok, I'll just wikilink them there then. Hopefully such a big find-and-replace with WikEd doesn't crash my browser!

t • c

) 22:01, 17 December 2014 (UTC)

Nope! Google Chrone took exception to such a large find-and-replace and stopped working.

t • c

) 00:35, 18 December 2014 (UTC)

Done! All wikified. Yeah,

cmn|3|...}}, but I'm not sure if that's worth doing for anyone that wants to copy the list directly from the page.   ~ Tom.Reding (talk|contribs|dgaf

) 04:28, 18 December 2014 (UTC)

How about we stop with the colored infobox nonsense and use a default Wiki color scheme? — Huntster (t @ c) 05:03, 17 December 2014 (UTC)

Many projects use coloured infoboxes, so as long as they don't have colour schemas that make the text hard to read, I don't see why not use them. It provides information to frequent readers of astronomy articles on Wikipedia immediately on entry to an article about the basic astronomical object type. -- 67.70.35.44 (talk) 06:18, 17 December 2014 (UTC)

@

Tetra quark (talk

) 13:54, 17 December 2014 (UTC)

Tetra quark: oh, I understand your reasoning, I simply disagree with the necessity of it (just as I disagree with the music project infobox colors). Perhaps I'm just bland. ;) — Huntster (t @ c) 14:28, 17 December 2014 (UTC)

• Oppose keep it light green, it has been that way for quite some time. Nebulae are most likely to be "light purple" related than galaxies. I do understand that greenish galaxies are rare, and there are more greenish nebulae. As dusty galaxies are red/infrared and elliptical galaxies are red, and distant galaxies redden, red would seem a more appropriate choice over the blue end of the spectrum. But I still think we should keep it the way it is. -- 67.70.35.44 (talk) 06:18, 17 December 2014 (UTC)

'not so astronomy-related'? I wasn't aware that any particular colour was associated with astronomy. Certainly I've seen no evidence that purple is! Modest Genius ^talk 12:43, 17 December 2014 (UTC)

@

Tetra quark (talk

) 17:05, 17 December 2014 (UTC)

That rationale makes no sense. Have you never seen astrophotography? Astronomical objects run the gamut of colours. Some galaxies are even greenish tinged. Green is not biology related, since many minerals that are obviously not biological, are green. As are stimulated emissions from chemicals. -- 67.70.35.44 (talk) 04:42, 18 December 2014 (UTC)

Personally, I think the template should stay green due to similar reasons as 67.70.35.44. The readers are already used to seeing green as meaning a galaxy here, and it is easy to tell at a single glance what type of object the article is about at the moment.

t • c

) 17:49, 17 December 2014 (UTC)

Recently, sentences containing terms such as "Earth mass", "Jupiter mass", "Solar mass" etc have been rewritten with symbols in many astronomy articles. There has been some discussion at Talk:Exoplanet#Mixed use of numerical suffixes. Since this affects more than just the Exoplanet article, I think it would be better to have the discussion here. These replacements were often done without regard to context, or the flow of a sentence or sufficent explanation to the reader of what the symbols meant. Also, M_E would be a better match with M_J than the M_⊕ that is used in the recent replacements. Astredita (talk) 13:33, 17 December 2014 (UTC)

• Oppose replacing terms with symbols that would make the articles inaccessible to lay people, and
  WP:JARGON -- 67.70.35.44 (talk
  ) 05:47, 18 December 2014 (UTC)

• blah has a mass of 30 Jupiter masses →

blah has a mass of 30 M_J

• "Neptune's mass equals 17 Earth masses, Jupiter has 318 Earth masses, and the 13 Jupiter-mass limit used in the IAU's working definition of an exoplanet equals approximately 4000 Earth masses." →

"Neptune's mass equals 17 M_E, Jupiter has 318 M_E, and the 13 Jupiter-mass limit used in the IAU's working definition of an exoplanet equals approximately 4000 M_E."

While "the 13 Jupiter-mass limit" is better left as-is.

This is assuming the symbols have been defined somewhere earlier in the text, of course.   ~ Tom.Reding (talk|contribs|dgaf) 13:24, 18 December 2014 (UTC)

I moved SkyFlubbler's reply here immediately below, since it was made on Talk:Exoplanet well after Astredita started this conversation. (Generally, I don't like moving people's talk; my appologies.)   ~ Tom.Reding (talk|contribs|dgaf) 13:36, 18 December 2014 (UTC)

I may suggest:

While yes, those symbols are shorter, but is it understandable? When we use the M_☉, M_E and M_J and so many others, we still need to link the article to it, rather than just typing the words and linking it (i.e, Solar mass, Jupiter mass and others)

Suppose a very new user who has not yet any experience in the Wikipedia reads symbols with M_☉, M_J. Obviously he will ask "What does that mean?"! Then he will still need to find what does "M" mean and what does the subscript mean before he understoods it, instead of just putting the words for him to not be confused. To be honest I misinterpreted M_☉ as "solar momentum" in my earlier years. I think Wikipedia is not about how we get well to the standards of information, it's about simplification of information to be understood by unknowledgeable readers.

Now before we ever add those symbols, at the introduction we must indicate them. But I was in thought of users who only want quick-reads stumbling upon the symbols such as M_☉. That may confuse him.

I clearly don't want the symbol M_Sun to be used as a replacement of M_☉, only for the reason it is more complex to construct. Suppose again unknowledgeable readers newly editing Wikipedia. Of course, he will try hard how to simulate the subscript. That will take time on him, plus confusion. And that's the beginning of misinterpretation.

With that being said, I may suggest to use the solar mass phrase and M_☉ template, but not the M_Sun or something like that; it's more confusing. SkyFlubbler (talk) 18:48, 17 December 2014 (UTC)

I have no objection to symbols, so long as they are explained in the article. Repeatedly writing out the name can be tiresome when it is used repeatedly. Similarly, using those symbols without explanation is inaccessible to non-experts. Treat them like any other unusual unit - define and link at first use, abbreviate thereafter if desired. Modest Genius ^talk 15:39, 20 December 2014 (UTC)

I noticed something about the List of largest known stars. First, recent edits done by Asyulus has produced some incorrect figures in the list. Example is VV Cephei A. The list states it as 1,475, although just to be honest when I checked the references I don't even saw that number. Another one is PZ Cassiopeiae, listed at 1,565, although like the former, no figure of 1,565 appeared in the references.

I come here to discuss. It's not really valid to get the middle point of stars' sizes if not stated in references. You cannot put 1,500 when the references say 1,000 to 2,000. References are very valid, we must not make our own views. I think more stars in the list are given the wrong sizes by Asyulus. Just to be honest, when I checked Asyulus on Google I've found out that he's a YouTube uploader of "Star Size Comparisons" Maybe he used Wikipedia in order to get his own benefit. Please judge me if I'm wrong, but the list has gone well worse since his edit. I now call on to people working on to that list to reimprove it.

Oh, next issue. The true list of largest stars, which is the top list, goes down to R Leporis at 500 R. But the top itself says "A survey of the Magellanic clouds...44 of them are larger than the 700 R...". Now why the list extends to 500 R when the 44 are not listed? The top itself says "...700 R cutoff point at this table". Now why the cutoff point is 500? I suggest to move the cutoff point back to 700 R since we don't list the 44 Magellanic cloud RSGs well.

Next, the comparison list is not aligned with the actual list, making it look narrower and more confusing for me. (Sorry, this issue is not as heavy as the formers, please comment lightly) What do you think, can we still separate it or join it? There's a script "The following...of comparison", anyway.

Comments please. If my comments are wrong, please take it lightly. SkyFlubbler (talk) 13:14, 18 December 2014 (UTC)

All I wonder is when VY Canis Majoris lost its tile and fell to the 9th position Tetra quark (talk) 14:28, 18 December 2014 (UTC)

Comment for Tetra quark; see Talk:List of largest known stars#VY CMa for the reason why VY CMa knocked down to 9th. SkyFlubbler (talk) 21:15, 18 December 2014 (UTC)

The comparison table was made separate because it was causing problems, per earlier discussions, as the way the table was formatted it was an excessive number of comparison stars. The solution was split it into a separate table. There should not be so many comparison objects in the main table as to overwhelm the number of actual entries. So keep the tables separate or delete most of the comparisons if we were to have only one table. We can always go for a cut-off of the top 100 stars, as with other tables, that would have a floating lower bound, based on the 100th star, instead of a defined radius lower bound. -- 67.70.35.44 (talk) 22:36, 18 December 2014 (UTC)

But I was thinking, the phrase at the top says the cutoff point is 700 R. I'm saying that, we must move it to 700 R instead of 500 R because there are 44 RSGs which we still need to join at the main if we put the cutoff point to 500 R. SkyFlubbler (talk) 04:23, 19 December 2014 (UTC)

Wait! This is urgent! Somehow Tetra quark was reverting again and again my edit in the list. I created that edit last few months ago and I was scolded. This is about adding some stars in the comparison list. Those stars are simply too small that they shouldn't be on the list. Plus, it dominates the main list. But somehow Tetra quark says it should be in there and in fact it needs more he says. I guess it was just a misinterpretation by Tetra quark.

Oh, I really need to move the cutoff point to 700 R. There are lots of stars beyond 500 R than those in the list. SkyFlubbler (talk) 22:47, 20 December 2014 (UTC)

Why not leave more information there instead of less? Also, as I said, those stars are good for comparison because they are well-known, unlike most of the others. But whatever, I am not gonna insist on adding them. Tetra quark (talk) 23:17, 20 December 2014 (UTC)

I noticed though, the usage of galactic coordinates is fairly common, yet I've never seen any template infoboxes that puts the galactic coordinates of objects. As for me, galactic coordinates are also easy to read. Also, galactic coordinates can also be formatted to epoch J2000. Comments? SkyFlubbler (talk) 10:08, 17 December 2014 (UTC)

Restatement to what I've said: Why are galactic coordinates not included in astronomical infoboxes, like for stars, galaxies, nebulae, etc. Professional astronomy uses galactic coordinates, even SIMBAD and NED themselves. Does Wikipedia don't allow such "infamous" system even though it has been used by professionals?

Plus, instead of having a list of astronomical objects by galactic coordinate system, why not include it to all infoboxes, so people can see it in the infoboxes. Comment please! SkyFlubbler (talk) 11:23, 17 December 2014 (UTC)

Probably just because no-one got around to writing the template code for it, rather than anything about being allowed or 'infamous'. Galactic coordinates are indeed sometimes used by professionals, although RA and Dec are more common. I don't see any harm in adding them, though they wouldn't be a huge benefit either as it adds no extra information compared to the equatorial coordinates. Which list are you referring to? Modest Genius ^talk 12:39, 17 December 2014 (UTC)

On the List of celestial bodies by galactic coordinate system, there are only very few objects, and I found it to be useless for many objects not listed. So I think, instead of just creating a list of celestial bodies and putting their galactic coordinate locations in there, it may be more comprehensive if the galactic coordinates are in their infoboxes. SkyFlubbler (talk) 18:10, 17 December 2014 (UTC)

Wow, such a list actually exists? Since such a list is impossible to be comprehensive, taking to AfD.

t • c

) 19:14, 17 December 2014 (UTC)

Per the comments on the discussion, for objects in the list to have data on galactic coordinates, I suggest if we make it as data on the infoboxes, which would affect so many articles. I am not sure, because of the wide range of artcles concerning celestial objects in Wikipedia, it will take more or less years before we put them in. SkyFlubbler (talk) 21:35, 17 December 2014 (UTC)

Oh wow. Who thought that would be a good idea? I've !voted on the AfD. Modest Genius ^talk 15:35, 20 December 2014 (UTC)

As long as Galactic Coordinates are only used in articles about specific items, and not list articles, that's fine. List articles, if they feature coordiantes, should only use RA/DEC because we'd be cluttering the lists with too many sets of coordinates. -- 67.70.35.44 (talk) 05:56, 18 December 2014 (UTC)

• conditional support I'm not opposed to incorporating galactic coordinates into existing templates, as long as they're linked to
  J2000 in the template, which apply to the current RA & Dec convention.   ~ Tom.Reding (talk|contribs|dgaf
  ) 15:37, 18 December 2014 (UTC)

galactic coordinate system seems a bid odd, it doesn't have examples of locations using galactic coordinates. I would think a short list of examples of prominent night sky features should be given with galactic and equatorial coordinates. -- 67.70.35.44 (talk) 05:56, 18 December 2014 (UTC)

• How would you limit the inclusion criteria of such a list? Two or three examples is fine, dozens is not. Modest Genius ^talk 15:35, 20 December 2014 (UTC)

• I guess I'm not opposed to the idea in principle, but so far I haven't seen any convincing argument that galactic coordinates are necessary. This proposal stems from a good intentioned, but ill-conceived list, and I'd find it odd if this was ultimately about compromising with a single user's wishes... Cheers, AstroCog (talk) 16:36, 21 December 2014 (UTC)

• I note that galactic coordinates are not mentioned in the index or glossary of the Explanatory Supplement to the Astronomical Almanac (3rd ed.). So although they may be used on occasion by professional astronomers, they seem to be secondary. This means they would be less accessible for editors who are not themselves experts, but are cleaning up after vandals or uninformed editors. Jc3s5h (talk) 16:48, 21 December 2014 (UTC)

Somehow I've just stood up at the article of IC 434 and the first sentence says: "The Flame Nebula is a bright emission nebula..."

What's going on? I think the real "Flame Nebula" must be

Good find. IC 434 is the emission nebula that is in the background behind the Horsehead Nebula. The Flame Nebula is (if the horse is upright) to the southwest of the head, below IC 434. I've adjusted the text accordingly. Primefac (talk) 17:20, 21 December 2014 (UTC)

As this is badly named, I've also nominated it for renaming, see

Hello all. Now that WP:Featured articles has seen its first decade, we are working through our oldest FAs to bring them up to modern standards. Two WP:AST articles from 2006—Enceladus and Crab Nebula—need a bit of attention. They are really in quite excellent shape considering their age, but both articles have acquired some uncited statements and external linkcruft over the years, and gone a bit outdated, as their main authors are no longer active. Hoping that I can get some subject matter experts to tidy them up and bring them up to date. I have watchlisted both articles and will help however I can. Thank you! Maralia (talk) 05:13, 27 December 2014 (UTC)

I'll try to pitch in at

t • c

) 05:51, 27 December 2014 (UTC)

Ping @

t • c

) 03:27, 29 December 2014 (UTC)

Hi there; this is just a quick note to let you all know that the 2015 WikiCup will begin on January 1st. The WikiCup is an annual competition to encourage high-quality contributions to Wikipedia by adding a little friendly competition to editing. At the time of writing, more than fifty users have signed up to take part in the competition; interested parties, no matter their level of experience or their editing interests, are warmly invited to sign up. Questions are welcome on the WikiCup talk page. Thanks! Miyagawa (talk) 21:54, 29 December 2014 (UTC)

Hi, guys. Somehow a well-intended user has created a new project that is related to ours, the Cosmology WikiProject. There are only three members in it, so anyone in here is invited to join. This project needs discussion, improvement, and members.

And, I think it must be a branch of ours, like the WikiProject:Astronomical Objects. Do it on its talk. SkyFlubbler (talk with me :-D) 20:45, 30 December 2014 (UTC)

The link is Wikipedia:WikiProject Astronomical objects. PrimeHunter (talk) 21:25, 30 December 2014 (UTC)

I am the creator of the project. Thanks for mentioning it here! If you guys intend to improve the page, make sure to take a look at the talk page and the edit summaries first. Thanks Tetra quark (talk) 23:20, 30 December 2014 (UTC)

Whilst clearing the unassessed articles for this project I came across a lot of subpages for the List of minor planets. Almost all of these subpages (each containing 100 minor planets) are duplicated in the larger 1000-planet lists. Should these subpages be deleted as duplicates? Primefac (talk) 05:50, 31 December 2014 (UTC)

In this case, the subpages are actually transcluded onto the larger pages (the ones with colons), so they are not duplicates. That being said, I can't see a reason to have the information in the articles contained in subpages, and would advocate for a merge-and-delete to the larger lists.

t • c

) 18:35, 31 December 2014 (UTC)

List of Solar System objects by size currently includes most of the uncertainties of the radii of the best-known objects, but notably lacking are those of Earth and the Moon, also from the infoboxes in their articles. More often, the uncertainties in those objects' densities and especially mass are missing.

Similarly, the uncertainty in the semi-major axes of those objects is normally missing. I have already found that the Moon's is known to near-millimeter precision and increasing at 3.8 cm/year, but strangely I have so far failed to dig up a more precise value of its semi-major axis than the one listed in its infobox. Moreover, the Moon's semi-major axis listed in orbit of the Moon is quite different from the one in its infobox, which means at least one of them is dead wrong.

Does anyone know of one or more sources that list these so that these can be added? --JorisvS (talk) 12:55, 31 December 2014 (UTC)

The accuracy of the measurements of the sizes of the Earth and Moon is far better than the non-sphericity both on a large scale (oblateness, etc.) and a small scale (mountains, basins, etc.). There is no point offering a ridiculously tiny margin of error for a single value for the size of these objects because it is entirely meaningless. There are detailed models of the lunar profile developed for purposes such as occultation timings, even more detailed models of the level of the Earth's surface, but these go far beyond what this article needs. I'll go look at the orbit numbers now ... Lithopsian (talk) 16:29, 31 December 2014 (UTC)

Yeah, it's not just you. I tried looking into this too, and all I found were very precise values for the radial velocity and change in precession rate, but no hard "the semi-major axis of the moon's orbit is: blah", anywhere in the 21st century finer than a km...   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  16:37, 31 December 2014 (UTC)

Orbital mechanics isn't me speciality, but I think I know what is happening here. The semi-major axis quoted in the main

Orbit of the moon article this is listed as the "inverse sine parallax" (although I'm not familiar with that term and I don't think it is in common use), while the semi-major axis value is the geometric mean distance of the earth-moon radius. Both are "correct". Lithopsian (talk

) 16:47, 31 December 2014 (UTC)

If you wanted, you could use 2 references - one for a semi-major axis at a certain date, and another for the velocity, and do the math in a note^[note], saying "as of year-end 2014, [etc.]".   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  16:51, 31 December 2014 (UTC)

On 2013-Jan-01 the semi-major axis of the moon was 2.56802E-03 AU. On 2014-Jan-01 it was 2.58208E-03 AU. On 2015-Jan-01 it will be 2.55964E-03 AU. There really is no neat one-size-fits-all solution because of on-going perturbations from the Sun, Jupiter, Venus, etc. -- Kheider (talk) 17:17, 31 December 2014 (UTC)

What's your source for those values?   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  15:06, 2 January 2015 (UTC)

The Earth-Moon-Sun interaction is complicated enough that when measured from the Earth-Moon barycenter, the apparent semi-major axis of the Moon undergoes substantial (+/- 1%) swings over the lunar orbit. If you want to define a semi-major axis for the moon, you presumably need to take some sort of long-term average. Computed by direct averaging, you'd need to consider hundreds of years of orbits to get a 1 km precision in the average, though I suspect one could probably find a better way of describing the parameter that eliminates the apparent variation due to the orbital interactions. It may be worth noting that the time-average rate of recession isn't actually measured directly from lunar distance, but rather inferred by using the range observations to measure changes in mean motion (i.e. ${\displaystyle {\dot {a}}=-{2a \over 3n}{\dot {n}}}$). Dragons flight (talk) 04:55, 2 January 2015 (UTC)

Concerning Wikipedia:Today's featured article/January 4, 2015, I've got a quick language question: if a star is "one of the strongest sources of ultraviolet radiation in the night sky", will a significant number of readers think that "strongest" means it puts out more UV than than other stars, not that its visibility from Earth in the UV spectrum is stronger? - Dank (push to talk) 23:02, 1 January 2015 (UTC)

It is quite clear to me that the "strongest source" must mean the source is stronger than other sources. If in the context of UV power I would assume it means the most powerful UV source. Dondervogel 2 (talk) 00:17, 2 January 2015 (UTC)

@

t • c

) 00:37, 2 January 2015 (UTC)

My suggestion is "one of the brightest sources of ultraviolet radiation in the night sky". Dondervogel 2 (talk) 00:48, 2 January 2015 (UTC)

This was worded correctly at Epsilon Canis Majoris. The correct statement is that it is "the brightest source of extreme ultraviolet radiation in the night sky"; the extreme ultraviolet distinction is important and can't accurately be omitted (and this statement is what the source says). —Alex (ASHill | talk | contribs) 05:03, 2 January 2015 (UTC)

Thanks for that correction! I've added the word "apparent" per this discussion and per John's edit ... he wanted to vary the prose a bit. - Dank (push to talk) 05:32, 2 January 2015 (UTC)

Am I being dense, or by "strongest" are we talking about strongest absolutely, as in ergs released by the object, or strongest relatively, as in ergs received from it on Earth. And even if we are talking relative, are stars really the strongest in general. What about the nearer galaxies, each collectively? And do other distant sources that emit in higher frequencies appear strongly in ultraviolet on Earth due to red shift because of the expansion of space? Even if these questions sound silly, I find the whole point of the statement confusing, because ... which stars? They vary absolutely so much according to class, and again even more relatively according to distance from Earth! Do not other objects somewhat fill in the range, and where does that leave the meaning? Evensteven (talk) 08:09, 2 January 2015 (UTC)

I think that even to an astronomy audience, it will be understood that "in the night sky" refers to "in the night sky of Earth" rather than as viewed from an exoplanet or from interstellar space. --John (talk) 13:01, 2 January 2015 (UTC)

You're not being dense. Thinking about this more, "strongest" is a lousy word, as indeed it's not clear whether it's referring to luminosity or brightness. In fact, I'd normally associate "strongest" more with luminosity than with brightness, though brightness is correct here. (This is clear to me in context, but I could probably be classified as an expert.) "Strongest" also doesn't appear in the source which supports the statement; "brightest" is the word used there. I'll change this in the Todays' featured article, Canis Major, and Epsilon Canis Majoris. —Alex (ASHill | talk | contribs) 17:25, 2 January 2015 (UTC)

Turns out that this issue was only present in the Today's Featured Article summary; "strongest" was introduced in the edited version of the lede of Canis Major. —Alex (ASHill | talk | contribs) 17:31, 2 January 2015 (UTC)

I am an amateur astronomer trying to do a simple thing: determine the distance and magnitude of stars.

The problem is: the figures for distance (LY) and magnitude (VIS) on the Wiki tables for constellations often, even for prominent visible stars, differ with the figures for same on the wiki links for the individual stars.

For example Jim Kaler publishes the distance to Beta Herculis as 148 light years, which agrees with the 'list of stars' distances published under the constellation maps in Wikipedia:

http://en.wikipedia.org/wiki/List_of_stars_in_Hercules

However, when we click on the Wiki link for individual stars in the list, e.g.:

http://en.wikipedia.org/wiki/Beta_Herculis

The page for the individual star reports a significantly different distance to the star (139 on 'star' page versus 148 on 'list of stars' page).

This is not an isolated example. I could cite dozens of cases where there is conflicting Wiki data.

Which distance is correct?

Is there a source that has the latest most accurate distances to stars? (e.g. Hubble parallax)

Thank you for your assistance.

Mark 23.29.196.252 (talk) 06:32, 31 December 2014 (UTC)

Nice find. Based upon the Hipparcos parallax data, Beta Herculis is more likely to be 43 parsecs (139 ly). However, we can launch a clean up for the list. Can you link those dozen stars so we can adjust them? I will try to use the Hipparcos data. SkyFlubbler ^(talk) 07:44, 31 December 2014 (UTC)

Does this mean I get an asteroid named after me? [LOL]

My data source is HYG at: http://www.astronexus.com/hyg (says it uses Hipparcos parallax distances circa 2006)

Using HYG (unknown validity) almost all the star distances are off in the Wiki 'list of stars' page by a material amount. I call anything over 1% difference material. By this time in astronomical observation we should have parallax distance pinned down don't you think?

Here are some examples of the prominent stars in Hercules: (distance LY)

BAYER	HIP	HD	W_Star	W_List	HYG LY	Diff	% Diff
β Her	80816	148856	139	148	139.2	8.8	6%
ζ Her	81693	150680	35	35	35	0	0%
δ Her	84379	156164	75.1	78	75.1	2.9	4%
π Her	84380	156283	377	367	376.7	-9.7	-3%
α1 Her	84345	156014	360	382	bad data
μ Her	86974	161797	27.1	27	bad data
η Her	81833	150997	112	112	108.7	3.3	3%
ξ Her	87933	163993	160	135	136.8	-1.8	-1%
γ Her	80170	147547	193	195	192.7	2.3	1%
ι Her	86414	160762	455	495	444.4	50.6	11%
ο Her	88794	166014	338	347	338	9	3%

(W_Star) is the distance on the Wiki Star's individual page

(W_List) is the distance on the Wiki Constellation All Stars page

Most of the time, the W_Star page matches the HYG distances. But in some cases it does not.

HYG has some corrupted data for some stars. It is not a reliable source.

Iamtoliman (talk) 16:01, 31 December 2014 (UTC)

There are many discrepancies like this in the various lists articles. There is no automatic mechanism for keeping them consistent with the individual star articles, hence when the star is updated with new data the list can become out of date. Feel free to bring them back into like, but don't just grab some number out of your head or a 20 year old blog and stuff it in. Usually an individual star article will have the latest and greatest data, but that isn't guaranteed so checks the references. Lithopsian (talk) 16:18, 31 December 2014 (UTC)

The HYG "blog" as you call it is a website that was updated in 2006, which makes it 8 years old. So, don't understand your comment 'some number out of your head'.

There is a scientific controversy as to the accuracy of the Hipparcos distances. I would direct your attention to the Wiki on Hipparcos, quoting:

The Pleiades distance controversy

One controversial result has been the derived proximity, at about 120 parsecs, of the Pleiades cluster, established both from the original catalogue[41] as well as from the revised analysis.[13] This has been contested by various other recent work, placing the mean cluster distance at around 130 parsecs.[42][43][44][45]

In August 2014, the discrepancy between the cluster distance of 120.2±1.5 parsecs (pc) as measured by Hipparcos and the distance of 133.5±1.2 pc derived with other techniques was confirmed by parallax measurements made using VLBI,[46] which gave 136.2±1.2 pc, the most accurate and precise distance yet presented for the cluster. According to the authors of the study, "The unrecognized nature of such an error is especially dangerous when one considers that Gaia, the successor to Hipparcos and very similar in design, is just now starting its Galaxy-mapping mission".

Based on these comments, not 'some number out of my head', my thinking is the Hipparcos data itself is suspect.

Iamtoliman (talk) 17:22, 31 December 2014 (UTC)

Not sure what your beef is. A blog, new or old, is not a reliable source for this sort of data. Neither is your own head. The Hipparcos data may be suspect, but that isn't for you to decide. If an alternative published paper derives a conflicting value and considers the Hipparcos data to be suspect then by all means put it in Wikipedia. Lithopsian (talk) 20:59, 2 January 2015 (UTC)

Perhaps we could get a bot to update the list of stars in xyz articles' distance parameters with the values from within the star articles themselves? That would make sure they are consistent.

t • c

) 18:33, 31 December 2014 (UTC)

Iamtoliman (talk) 19:45, 31 December 2014 (UTC)

Regarding data - alot of this highlights just how difficult and fiddly estimating distance actually is. The pleiades example shows that even researchers have challenges. The main thing is that articles can list more than one distance and hopefully identify the sources of that measurement. (This holds true for luminosity mass etc.). Presenting science like this I think is actually more fascinating than handing down data like it came from the ten commandments or something. Cas Liber (talk · contribs) 20:59, 1 January 2015 (UTC)

The first thing we learned in Physics was every scientific measurement must come with a +/- range of its accuracy.

The second thing we learned was when you add two estimated figures, you must combine the +/- range of each estimate.

So 10 +/- 2 PLUS 3 +/- 4 EQUALS 13 +/- 6

The masses out there [awful pun] will not appreciate this nicety, but the boffins certainly will, along with any serious student actually trying to use the data, not just admire it like candy in a window.

23.29.196.252 (talk) 02:26, 2 January 2015 (UTC)

If those errors are a multiple of a

error propagation

would tell you that the sum is ${\displaystyle 13\pm {\sqrt {2^{2}+4^{2}}}\approx 13\pm 4.5}$. Dragons flight (talk) 07:28, 2 January 2015 (UTC)

Full disclosure: I was a professional statistician by trade. Hence, squinting at data comes natural to me. But concerning the errors, "IF" means "(I) have not the (F)aintest idea". Iamtoliman (talk) 13:49, 2 January 2015 (UTC)

Source

As a general point to everyone here: distances need to be cited to

This image is a nice way to compare the sizes of natural satellites to each other and to the terrestrial planets, but some things are wrong. First, Pluto is in there. Secondly, Mars is too small relative to Ganymede, though roughly right relative to Earth. Is there someone who'd like to fix this? --JorisvS (talk) 17:55, 5 January 2015 (UTC)

First, Pluto has every right to be in there. Second, does that mean that Ganymede is too large relative to Earth? Primefac (talk) 18:20, 5 January 2015 (UTC)

A) No, Pluto is neither a satellite nor a (terrestrial) planet. If it is included, the other dwarf planets would also have to be included, but that makes a different comparison, which also be a nice one, though. B) On closer inspection, the problem of the sizes appears much more complicated. Earth is a bit too small compared to the rest, except Ganymede and Titan, which are much too big compared to the rest. And I may not have spotted all of the problematic sizes. --JorisvS (talk) 19:42, 5 January 2015 (UTC)

Sizing issues aside (which I will work on fixing and reuploading), the description on the image is "Relative sizes of the 25 Solar System objects smaller than Earth." It makes no implication about Pluto's status, and neither do any of the en.wiki pages that use it (one even says "dwarf planet Pluto." Primefac (talk) 20:06, 5 January 2015 (UTC)

(and yes, I am being incredibly pedantic on this one). Primefac (talk) 20:11, 5 January 2015 (UTC)

I think it would be best if there are two: the satellites compared to the planets and everything. Note that the image's title is "relative satellite size", that's why I said that it was wrong that Pluto was in there: aside from the inner planets, it's the only one included. I think the description got changed later, because it includes more than just satellites, notably Pluto, and then it was added that all those other objects are missing. --JorisvS (talk) 23:05, 5 January 2015 (UTC)

The image will be fixed (see below), so I'll make sure to give it a suitable name before uploading. Primefac (talk) 23:38, 5 January 2015 (UTC)

To answer the size question - if Earth were to scale with everything else in this picture, Io would only be one pixel wide (and 3/4 of the bodies sub-pixel size). Therefore, either Earth becomes a larger-than-the-frame segment (like the Sun in most Planet pictures) or it gets nixed altogether. Best option is probably scaling everything relative to Nereid or similar-sized body. Primefac (talk) 21:58, 5 January 2015 (UTC)

Io is approximately 2/7th the size of Earth, so it would be substantially bigger than one pixel. Your strategy sounds sound, though. --JorisvS (talk) 23:05, 5 January 2015 (UTC)

Yeah, turns out I'm just an idiot and didn't remember to set my spreadsheet formula properly. All the current images will fit perfectly fine on the current image with only minor tweaking necessary. I shall do that post-haste. Primefac (talk) 23:38, 5 January 2015 (UTC)

@JorisvS:, if this looks good to you, I'll upload and switch all the wikilinks.Primefac (talk) 12:53, 6 January 2015 (UTC)

Already much better, though their placement is a bit irregular: the southern poles are now not at the same height. --JorisvS (talk) 13:39, 6 January 2015 (UTC)

You missed one: Enceladus looks too big. It should be just a touch bigger than Miranda, and about half the size of Tethys. Maybe you confused diameter with radius? Tbayboy (talk) 13:42, 6 January 2015 (UTC)

Thanks for catching that. It was already way too big in the original. Also, Rhea and Oberon are best switched positions. Although the same size to within uncertainty, Rhea is likely the bigger one. --JorisvS (talk) 13:55, 6 January 2015 (UTC)

To be honest, I didn't mess with the top row since they were fairly close to what they should be. Should have figured someone would notice :p The south poles weren't all at the same height to start off with, but I suppose they did get a bit more skewed. Primefac (talk) 14:32, 6 January 2015 (UTC)

I hadn't noticed, but their placement should be regular regardless. --JorisvS (talk) 14:42, 6 January 2015 (UTC)

Done, comments welcomed. Primefac (talk) 15:45, 6 January 2015 (UTC)

• Visually-speaking, I think it looks good except for the gray box around Callisto. — Huntster (t @ c) 16:05, 6 January 2015 (UTC)

• I checked and found no mistakes. If you could make Triton and Pluto images overlay with the other images on the left, it'd be better. Tetra quark (talk) 16:11, 6 January 2015 (UTC)

Done. Primefac (talk) 18:42, 6 January 2015 (UTC)

• Could you also switch Rhea and Oberon? And could you remove Pluto from this satellites comparison and then make another one that includes it, along with at least Ceres and Vesta (and maybe the other (IAU) dwarf planets if it can be made to look okay). --JorisvS (talk) 16:17, 6 January 2015 (UTC)

I suppose Rhea is slightly smaller than Oberon. Primefac (talk) 18:42, 6 January 2015 (UTC)

No, it's slightly larger. --JorisvS (talk) 19:55, 6 January 2015 (UTC)

• For near-future consideration: If Ceres and Vesta are added, then later this year this could become a montage of all the larger, sub-Earth-sized, imaged bodies (after an update). Tbayboy (talk) 17:53, 6 January 2015 (UTC)
• Some of the names don't look horizontally centered, like at least Enceladus, Miranda, Proteus, and Nereid (by visual approximation only). Can you line up all names with their object centers (for pedantry's sake)? Looks great otherwise!

Good point, will do! Primefac (talk) 18:42, 6 January 2015 (UTC)

• Also, the bottom of the Moon's image appears slightly higher than the bottom of the other images.

The bottom of all images are perfectly aligned. I checked that before. Tetra quark (talk) 17:26, 6 January 2015 (UTC)

• "Earth" doesn't appear in all caps like everthing else. Though that may be on purpose, idk.   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  17:09, 6 January 2015 (UTC)

Yeah, I noticed that, it was in the original image and I forgot to fix it (but I will). Primefac (talk) 18:42, 6 January 2015 (UTC)

• There is also a weird streak over the image of Venus. --JorisvS (talk) 18:22, 6 January 2015 (UTC)

The image I used was the satellite image from NASA, it's the bit where the satellite didn't go over. I might be able to find another complete one, I just didn't like the lower-quality version in the original. Primefac (talk) 18:42, 6 January 2015 (UTC)

That would make it look better. --JorisvS (talk) 19:55, 6 January 2015 (UTC)

Hopefully this meets the majority of the above comments. Everything is lined up, Pluto has been shifted, Rhea/Oberan switched, and the top row is sized properly. Primefac (talk) 22:32, 6 January 2015 (UTC)

It looks like it belongs in a book or encyclopedia or something.   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  22:42, 6 January 2015 (UTC)

I still think Pluto is out of place in the current comparison, but it looks way better than it used to! --JorisvS (talk) 23:14, 6 January 2015 (UTC)

I like Pluto there as a nice right-hand bracket. Plus, Charon appears on top, so it's more than appropriate to have Pluto on the bottom.   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  00:03, 7 January 2015 (UTC)

If Charon were the reason to include it, we should include all four giant planets, because their moons are in here. What good reason really is there to include it? Sentiment isn't. --JorisvS (talk) 10:38, 7 January 2015 (UTC)

The description says it's for "Solar System objects smaller than Earth", so including the gas giants would change the scope of the image. Including Pluto wouldn't. I'm not one for sentiment, but I don't want to swing too far in the opposite direction either and actively reject its presence. Pluto's a thing, people know about it/of it, and it's nice to know how big it is compared to everything else. Simple as that. If nothing else, it helps illustrate where on the size-spectrum a dwarf planet sits.   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  13:19, 7 January 2015 (UTC)

Preach it, Brother Reding! AstroCog (talk) 14:43, 7 January 2015 (UTC)

And the title says satellites. I'm not against Pluto's inclusion in a comparison like this one, but if included other objects in the presented size range should also be included. --JorisvS (talk) 14:47, 7 January 2015 (UTC)

I understand your point. There are several satellites lined up and Pluto is a combo-breaker. But there are also three planets in there, so people will understand its not just about satellites. And the reason for adding Pluto is because it is a very well known object. There is no point in adding other similar sized bodies that nobody has heard of Tetra quark (talk) 15:00, 7 January 2015 (UTC)

At least Ceres and Vesta with Dawn. Eris is also a candidate because it led to Pluto's "demotion", though it has no real usable image, but maybe that can be solved akin to Pluto. Then, if three of the five IAU dwarf planets are included, why not all five? --JorisvS (talk) 15:10, 7 January 2015 (UTC)

If 5 can fit, sure, if Primefac doesn't mind adding them >.>   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  15:28, 7 January 2015 (UTC)

Sorry I'm only seeing it now, but could a better image of Europa be used? And maybe we could also use higher-quality images of Earth, Mars, and Mercury? --JorisvS (talk) 16:05, 7 January 2015 (UTC)

Too late, it's already done. I may update the image with higher-res images if I can find them, and/or add more bodies, but no guarantees. Primefac (talk) 19:28, 7 January 2015 (UTC)

WikiMedia:User:SteinsplitterBot/Possible copyvios wasted no time, it seems. Just wanted to let everyone know.   ~ Tom.Reding (talk ⋅contribs ⋅dgaf)  21:22, 7 January 2015 (UTC)

What would be the possible copyvio about it?? --JorisvS (talk) 21:57, 7 January 2015 (UTC)

I'm not overly surprised, it's very similar to an image that already exists. It's a bot that flagged it, though, and when a human actually looks they'll see it's a derivative work (which is perfectly acceptable under the licence it was created). Thanks for the heads up, though, Tom! Primefac (talk) 12:22, 8 January 2015 (UTC)

Follow up

I'm thinking of putting this image work of art up at each satellite's page, and maybe some of the planets' pages, as long as:

Decreasing in size (for the lazy) (not struck = missing some kind of size-comparison):

Satellites:

Mimas (moon), Nereid (moon)

Planets: Earth, Venus, Mars, Mercury (planet)

Dwarf planets: Pluto