Talk:List of gravitationally rounded objects of the Solar System

message: Shouldn't synodic day lengths be added to the tables? 76.66.196.229 (talk) 11:42, 6 February 2009 (UTC)
thread_title: Days

message: Actually, Ckatz, per you revert edit line "not our place to second-guess this; the people who created the category also get to populate it", I'm not second guessing. What we have listed under dwarf planets are not dwarf planets, but bodies named as dwarf planets. We have an entire section of likely dwarf planets which have not been named as such. If the category "dwarf planet" is defined by what the IAU names a dwarf planet, then we need to make that explicit in the intro. But all our refs say otherwise: that a body is a dwarf planet because of geological and orbital parameters, regardless of its recognition. No IAU publication I've seen says "the people who created the category also get to populate it," they assume that the category is populated by the objects themselves. Therefore we need to inform our readers that we likely know of many other dwarf planets which aren't on this list, which looks misleadingly comprehensive. kwami (talk) 19:40, 6 February 2009 (UTC)
replies: text: There are currently only five objects in the Solar System that are categorized as dwarf planets. We are not misleading the readers as there is a section below it that clearly indicates other potential candidates. --Ckatzchatspy 20:52, 6 February 2009 (UTC)
thread_title:  Accepted dwarf planets 

message: Why did someone add the ~30 km diameter asteroid Ganymed to the potential dwarf planets list? I'd fix it, but I'm terrible with Wiki tables and I'm just on my way to bed. --Patteroast (talk) 06:32, 7 April 2009 (UTC)
replies: text: Reverted. kwami (talk) 07:17, 7 April 2009 (UTC)
replies: text: So are a lot of river rocks. The list could get quite lengthy ... kwami (talk) 15:59, 7 April 2009 (UTC)
thread_title:  Ganymed? 

message: The pictures of dwarf planets are a mixture of real images and artists conception. Is this OK or is the Wiki way to have real images for all.
Carlwev (talk) 19:14, 14 September 2009 (UTC)
replies: text: Real images are preferred, but artist's conceptions are sometimes all there is. Serendipodous 20:13, 14 September 2009 (UTC)
thread_title: Pictures

message: Shouldn't "the Moon" be identified by it's name like the other satellite objects?
Lonelyksdem (talk) 20:01, 17 November 2009 (UTC)
replies: text: The Moon's name is "the Moon" (capital M). Serendipodous 20:05, 17 November 2009 (UTC)
thread_title: Luna

message: Obviously more objects will get included on this list as time passes, but I find the current content to be missing a few objects. . Haumea makes the list by virtue of its dwarf planet status even tho it is of irregular shape. . Proteus (420km) dos NOT make the list even tho it is larger than Mimas (397km) and the reason given is that Proteus has an irregular shape. . I also don't see Vanth (660km). . Does anybody see reason to make the change and add columns for Proteus and Vanth ?  —Preceding unsigned comment added by Skiz nem (talk • contribs) 20:58, 11 October 2010 (UTC)
replies: text: It's not due to regular shape. It's due to hydrostatic equilibrium. Haumea is in hydrostatic equilibrium, but stretched out by its rapid rotation. Proteus would be in hydrostatic equilibrium, but is too cold. Vanth is too small to be in hydrostatic equilibrium, so is not included. Serendipodous 21:03, 11 October 2010 (UTC)

text: The cited value for Vanth's diameter is 280 km. Oh, wait, yeah, I see, someone called the diameter the radius. Common mistake there. Serendipodous 22:17, 12 December 2010 (UTC)
replies: text: The shape of a small candidate probably has more to do with composition/density then temperature. -- Kheider (talk) 02:52, 13 December 2010 (UTC)
replies: text: In the case of Proteus though, it would appear to be temperature, as Proteus's composition is similar to that of Mimas, which is spherical. Serendipodous 10:38, 13 December 2010 (UTC)
thread_title: Objects that made the list while other didn't

message: I've corrected it to 23.44°. The source, JPL's planetary fact sheet was wrong, and I have informed the author of the site. This is not just a new, improved figure, or one that is in dispute. This has been the value since late 1917. Saros136 (talk) 22:39, 13 November 2010 (UTC)
thread_title:  Obliquity of the ecliptic value 

message: Move to "List of planetary-mass objects in the Solar System"? 
We could either remove the section on the Sun, or leave it in for comparison purposes, but this would take care of the titling issues, and also make the article a more convenient target for links (say in planet, in the planemo section). — kwami (talk) 16:54, 6 February 2012 (UTC)
replies: text: Don't really see the difference between this and using Basri's definition. Since Basri's definition of "planemo" is an object in hydrostatic equilibrium that doesn't fuse, all it really does is add another layer of explanation. Serendipodous 20:32, 6 February 2012 (UTC)
replies: text: I think it would be useful because we talk about 'rounded' bodies in many other articles, and we never mean stars. In such cases we could link here for examples, but people might object if we only mean PMOs and this article isn't restricted to PMOs. The only extra layer of explanation would be "isn't a star", and because we could link to the planemo section of planet for explanation, it would actually mean fewer layers of explanation here. I think it would also be a more accessible title than "gravitationally rounded", which can convey the false suggestion that the objects are round, and in itself therefore requires more layers of explanation. — kwami (talk) 21:27, 6 February 2012 (UTC)

text: See the previous discussion on "This article needs a better name". "Planetary-mass objects" is okay for accuracy, but I think it's a stretch for the layman looking for "big, round things" including satellites, since the "planetary" suggests (to the naive reader) "not a satellite". I.e., it's moving away from a descriptive title to a technical term title -- back towards the H-E problem (although not as bad as that one). Also, how does a name change make linking more convenient? The planemo section can link to this article as is; the caveat is already in the lead. Tbayboy (talk) 16:36, 9 February 2012 (UTC)
replies: text: Perhaps you're right. — kwami (talk) 16:52, 9 February 2012 (UTC)

text: This WAS merged with that page. But Dojarca obviously unmerged it. The layout would be rather difficult to maintain with lists as long as this page's, and I would rather keep the information than lose it for the sake of layout. And can someone please explain to me why any article needs "surface area system summary" or even how that could be determined to any satisfactory degree? Serendipodous 22:51, 22 May 2012 (UTC)
replies: text: I don't know why anyone would need it, but it's easy enough to calculate, since they're ignoring gas giants. I suppose the surface area of the galileans compared to that of Earth might be of some interest to someone. — kwami (talk) 02:25, 8 June 2012 (UTC)

text: I feel List of gravitationally rounded objects of the Solar System should be the main article as it already has a much greater amount of data, tables and references, the term gravitationally rounded more accurately describes the objects than planet-mass, which would only confuse the reader into thinking that the article is solely on planets , also surface area is calculated by the simple formula 4 x pi x radius squared. – Phoenix B 1of3  (talk) 01:20, 8 June 2012 (UTC)
replies: text: Many asteroids are gravitationally rounded to some degree, yet not in HE. And then of course there's Methone. 'PMO' is the accurate term, though accessibility is an issue. — kwami (talk) 02:13, 8 June 2012 (UTC)
replies: text: Methone should be discounted, it is definitely roundish, but at a mere one mile across it most certainly has not reached hydrostatic equilibrium, as for the name I am leaning towards gravitationally rounded which would imply hydrostatic equilibrium as it inquires the object is large enough for its gravity to be strong enough to conform everything into a spheroid, such would exclude methone as its shape is merely the result of the way the dust settled, not pressed into shape by strong amounts of gravity. But if the proper name is planetary-mass objects perhaps we should further elaborate on it in the introduction, planetary-mass objects is an unlikely search term for someone unfamiliar with the topic as most would assume that it simply implies the planets and not there larger satellites. Also though too long to be a proper title, List of gravitationally rounded objects of the Solar System to have achieved hydrostatic equilibrium would be a good description of what qualifies to be included as such in this list. – Phoenix B 1of3  (talk) 17:43, 8 June 2012 (UTC)
replies: text: That's the way the dust settled ... due to gravity. So it's gravitationally rounded. The accurate title would be list of Solar System objects in hydrostatic equilibrium, but that has accessibility issues. (Methone's surface is in HE, but presumably not its sub-surface. The IAU def speaks of rigid-body forces.) — kwami (talk) 22:54, 8 June 2012 (UTC)
replies: text: List of Solar System objects in hydrostatic equilibrium sounds very fitting and proper for an article title, we'll just need to create some layman term redirects to the article, the redirects would make it more accessible. – Phoenix B 1of3  (talk) 23:23, 8 June 2012 (UTC)
replies: text: I agree, especially, as Kwami pointed out, because there are many asteroids that are somewhat gravitationally rounded but are not in HE. --JorisvS (talk) 10:43, 9 June 2012 (UTC)

text: Note that "... in H-E" was the title of this article, and it was changed to the current after some discussion. The current title is trying to strike a balance between technical accuracy and approachability. The content, however, is intended to be "bodies in H-E", as the lead indicates. Tbayboy (talk) 15:15, 9 June 2012 (UTC)
replies: text: Yes, that's always been the problem. The history of the articles has shown that even some of us editors have not understood what HE is, thinking for example that a body cannot be in HE unless it is round—though the current title doesn't do much to clarify that point. — kwami (talk) 15:37, 9 June 2012 (UTC)
thread_title:  move? 

message: That merge tag has been up there for months. Can we just merge it back? It was only recreated out of spite. I've made a full case here. Serendipodous 07:46, 28 October 2012 (UTC)
replies: text: I like the layout of the other one better in some ways, but I don't think there's anything to actually merge. If there is, it can be added later or suggested here. Turned into a redirect. — kwami (talk) 08:04, 28 October 2012 (UTC)
thread_title: Merge

message: Appears that Methone may be in HE, and assuming that we don't want to start adding bodies like that, I renamed the article to PMO's. — kwami (talk) 22:05, 22 May 2012 (UTC)
thread_title: Naming thread from [List of planetary-mass objects in the Solar System] fork

message: Could we reduce the precision of the rotation period, orbital period, and eccentricity to 3 digits in the tables?  The large number of digits make these entries difficult to quickly scan and compare values.  A reader desiring greater precision can follow the link to the main article on the object to get it.  Three digits seems to be enough precision to differentiate between the entries and short enough to quickly scan.--Wikimedes (talk) 17:59, 26 January 2013 (UTC)
thread_title:  Excessive precision 

message: The Moons of Mars, Phobos and Deimos are not writed in the list-table of natural satelites in the solar system in this article, that is a mistake... I think, I dont know, or are those in another space category?--Feroang (talk) 03:21, 15 January 2014 (UTC)
replies: text: Read the article title: neither Phobos nor Deimos come close to qualifying. Tbayboy (talk) 05:31, 15 January 2014 (UTC)

text: Yes, there _is_ another space category: Phobos and Deimos are listed on the page List_of_moons.  That article does not need to care whether the moon is gravitationally rounded or not. jimswen (talk) 21:06, 24 February 2014 (UTC)
thread_title:  [[Moons of Mars]], [[Phobos (moon)|Phobos]] and [[Deimos (moon)|Deimos]], unlisted, why? 

message: Shouldn't the section on dwarf planets be before the section on satellites? You have Charon listed before Pluto the way it is now. It doesn't seem natural to have satellites first. Fyunck(click) (talk) 06:54, 14 May 2015 (UTC)
replies: text: The problem is the final "likely dwarf planets" list. Since that list by definition will never end, it's best to keep it at the bottom, and the dwarf planets list really only works above it. Serendipodous 07:19, 14 May 2015 (UTC)
replies: text: I agree with the "likely dwarf planets" being best at the bottom, but I have no idea why you would say the dwarf planets list really only works above it. It seems out of synch to me being anywhere except right below the planet listing. Does everyone at the Astronomy Project agree with the current order where moons of dwarf planets get listed before the dwarf planets themselves? Fyunck(click) (talk) 09:22, 14 May 2015 (UTC)
replies: text: Contentwise it is actually more like a subsection of the section "Dwarf planets" rather than an independent section (despite it having the L2 header). Maybe it is best given an L3 header. --JorisvS (talk) 09:32, 16 May 2015 (UTC)
thread_title:  Article ordering 

message: The TNOs Makemake, Ixion, Varuna, UQ513, OR10 and Sedna have no moon, so their mass can only be guessed. Please everybody, don't add unreliable masses in such a case, better put a question mark, or a lower and upper limit with reference. Thanks & regards, Herbmuell (talk) 03:20, 28 January 2016 (UTC)
replies: text: All unreferenced masses are calculated assuming Pluto's density, as noted in note F. Serendipodous 19:30, 28 January 2016 (UTC)
replies: text: Actually it uses 2. Pluto's has since shrunk to 1.86. :-) Tbayboy (talk) 00:04, 29 January 2016 (UTC)
replies: text: Then they probably need to be changed. Serendipodous 00:23, 29 January 2016 (UTC)
thread_title:  Unreliable masses of TNOs 

message: For bodies with only exospheres, should we really list a atmospheric composition? Listing the components of the Moon's "atmosphere" for example gives the mistaken impression that it has a permanent atmosphere like Earth and Mars when it doesn't. I think for bodies like Mercury or the Moon, it's better to list "none", or maybe "exosphere only". Oiyarbepsy (talk) 05:43, 11 May 2016 (UTC)
thread_title:  Exospheres and atmospheric composition 

message: The wording of the lead goes against WP:THISISALIST ("If the page is a list, do not introduce the list as "This is a list of X" or "This list of Xs..."") and should be amended. Lizard (talk) 00:04, 15 January 2017 (UTC)
thread_title:  "This is a list" 

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thread_title:  External links modified 

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thread_title:  External links modified 

message: Where do the symbols €, ₤, $, ₩, ₦ and ¶ for satellites of Earth, Jupiter, Saturn, Uranus, Neptune and Pluto come from? I tried to find a source, but all I find are 3rd party articles that eventually lead back to this Wikipedia article.
If there is an official source for these, great - then it should be cited. If not then I see no reason to use these symbols. Why not use the official symbols for the planets instead? Renerpho (talk) 17:56, 22 July 2018 (UTC)
replies: text: They are not used here as official symbols, but rather just as a key for the table, comparable to the keys used earlier in the article. That said, if you know how to technically replace them with the planet symbols, I would certainly see it as an improvement-- more clear and intuitive. Go for it! A2soup (talk) 18:42, 22 July 2018 (UTC)

text: I went ahead and did it myself. I like it, thanks for the suggestion! A2soup (talk) 18:55, 22 July 2018 (UTC)
thread_title:  Symbols for satellites - source? 

message: Any reason we don't list surface pressure? Seems to fit with gravity, surface temperature, and atmospheric composition. Nfitz (talk) 00:11, 23 March 2019 (UTC)
thread_title:  Surface Pressure 

message: The article for Titan states that it is gravitationally rounded. Why isn't it on the list? Cynthia-Coriníon 16:11, 30 August 2019 (UTC)
replies: text: Look again: it's in the satellites section. Tbayboy (talk) 16:20, 30 August 2019 (UTC)
thread_title:  Titan? 

message: It says:
:"Several of these [satellites] were once in [hydrostatic] equilibrium but are no longer: these include Earth's moon and all of the moons listed for Saturn apart from Titan and Rhea.[citation needed]"
I personally know nothing about this, but according to some tidbits found on the Internet, at some nitpicky level, pretty much NONE of Solar System bodies are technically in exact "hydrostatic equilibrium", which, if true, would somewhat invalidate the whole usefulness of such a criterion. Or, if a "near enough" approach is adopted, then is the Moon also not "near enough"? It looks pretty round to me. 2A00:23C5:4B91:AB00:B43B:4214:20F:399 (talk) 21:04, 30 April 2020 (UTC)
thread_title:  Moon in hydrostatic equilibrium 

message: I have a question about the orbital periods given for the major planets. Those are given in days and years (the latter being defined as 365.25 days on the linked wiki page). However, that ratio doesn't match. For instance, the numbers for Earth give a ratio of exactly 365, while the other planets give ratios in the range of 365.20 to 365.37 days. Why is that? Additionally, one might assume that P=a^{1.5}, but that doesn't match, either: The periods for Mercury to Mars are a little bit too large, the periods for Jupiter to Neptune are a little bit too small. What am I missing? Renerpho (talk) 07:20, 25 February 2021 (UTC)
thread_title:  Question about orbital periods 

message: I'm not sure where "0.33" comes from, since the paper being cited does not have that figure. Is it from reading the graphs in Fig. 3?
But also, that paper shows varying inclinations and obliquities for all four Galilean moons, so it seems the figures we have may be wrong. The text gives:
           	Io                  	Europa           	Ganymede       	Callisto
Inclination	0.0041° ± 0.0073°   	0.468° ± 0.023°  	0.204° ± 0.074°	0.15°–0.70°
Obliquity  	0.000405° ± 0.00076°	0.0965° ± 0.0069°	0.155° ± 0.065°	[not stated]
The values for Callisto's obliquity are not stated, but on the graph it seems to go between 0.1° and 1.8° over 2000 years. Double sharp (talk) 08:38, 8 August 2022 (UTC)
replies: text: Looks to me like it's from the figure, yes. I would interpret the uncertainties as the standard deviation, not the maximum deviation (which is only given in the figure). Note: I corrected one of the values in your table, I hope you don't mind. Renerpho (talk) 01:45, 9 August 2022 (UTC)
replies: text:  I forgot to tag you. Renerpho (talk) 01:46, 9 August 2022 (UTC)
replies: text: Regarding Callisto, quote:  The range is 0.55, and 3-4 times that would be 1.65-2.2. That is, varying between 0(?) and 1.65-2.2 degrees. I don't know why no concrete values are given, but if I'd have to hazard a guess, I'd blame the fact that there is quite a strong secular component to how the obliquity changes (there is a linear trend downwards over the time period studied), and the period at which it oscillates is quite slow. So just taking the values from that time period and computing mean and standard deviation would be crude. Renerpho (talk) 01:54, 9 August 2022 (UTC)

text: Nothing in this universe has 0 obliquity. Claiming all of them to be 0 is sketchy, especially with no sources whatsoever. I'd call 0.3° pretty close to 0 though. Nothing like Earth's moon. I suggest to replace all the 0's by ≈0, and call it a day (except where actual non-zero values can be cited from the literature, like for the ones we've discussed here). Renerpho (talk) 17:31, 9 August 2022 (UTC)
replies: text:  Yeah, that sounds good to me. They are probably all close to 0 anyway, even if not exactly there. For now I only found non-zero values for the Galileans and Titan, so it'd be those, I suppose. Double sharp (talk) 03:59, 10 August 2022 (UTC)

text: Oh, also found Triton. Double sharp (talk) 04:00, 10 August 2022 (UTC)

text: Agreed. I suggest to add a note to the Callisto value, stating something like "Callisto's obliquity is varying between 0 and about 2 degrees on time scales of thousands of years". The article already has a "notes" section. Renerpho (talk) 18:04, 28 August 2022 (UTC)
replies: text:  Okay, done. :) Double sharp (talk) 07:17, 29 August 2022 (UTC)
thread_title:  Ganymede's axial tilt 

message: See Talk:List_of_Solar_System_objects_by_size#We_CANNOT_measure_the_mass_of_any_of_these_objects, from Jamescobban (talk) 22:54, 19 April 2024 (UTC)
thread_title:  We CANNOT measure the "mass" of any of these objects