Talk:Moons of Jupiter/Archive 1

With the inclusion of the recently discovered moons, the column with the 'groups' of moons has gone all out of whack.. is it really needed? Perhaps it could be mentioned seperately which moons were thought to be in groups, and on the table simply list them by average orbital distance. --Patteroast 22:05, 17 Apr 2004 (UTC)


 * Perhaps it would also be worth adding the orbital inclination, which is necessary to see why they have been grouped the way they are. --Keith Edkins 08:06, 25 Apr 2004 (UTC)

Interesting that the link at the bottom of the page says that Sheppard hinted at 20 additional moons in the phone interview. I guess we should wait for an official discovery announcement to say more about them. --Matt McIrvin 13:06, 5 May 2005 (UTC)

pronunciation
I've been able to verify most of the pronunciations. A few, marked with question marks, are pretty straightforward but not verified. On a couple (Erinome, Chaldene, Kallichore), the placement of the stress is unknown - and the people at JPL & NASA have no idea. In a few cases (Adrastea, Dione, Elara), various sources give conflicting opinions on where the accent should be, but this is a result of trying to capture the original Greek pronunciation. Such a philosophy would mean pronouncing Ganimede as GAN-i-MEE-dee and Titan as tee-TAN, so I've stuck to the classic English pronunciations.

Greek final -ee, -ie, -ea, -ia are disyllables and homophonous in English. You will occasionally see them with a dieresis over the final e, as -eë, -ië. --kwami


 * Okay, got the rest, but there's unresolved disagreement with Elara. kwami 09:47, 2005 May 9 (UTC)


 * I've removed all those ridiculous aspirated 'h' sounds at the end of syllables that make them sound as though pronounced by a wheezing asthmatic - MPF 21:56, 22 May 2005 (UTC)


 * Two problems: 1. There are no "aspirated 'h' sounds at the end of syllables". Oh is the sound of the word "oh". Oe as a syllable doesn't intuitively mean anything in English. If you don't understand the transcription system, there's a key linked at the top of the table. It's a pretty standard cross-dialectical system, actually, like you'd find in any lay mythological glossary.
 * 2. Of the 13 pronunciations you changed, 9 are now wrong: You have Thelxinoe rhyming with "deny", Europa rhyming with "papa", etc. I'll change them back. If you have specific objections to the system, let's discuss it here first, so that any changes are systematic. kwami 22:20, 2005 May 22 (UTC)
 * Ref. 1. above, there are; a pronunciation guide is to indicate pronunciation by showing each letter to be pronounced; the 'h' in ah and oh indicates an 'h' sound (aspiration), to be pronounced. If there's no aspiration, there shouldn't be an 'h' in the pronunciation guide. - MPF 22:52, 22 May 2005 (UTC)
 * There is no monoliteral 'h' in the pronunciation guide! It specifically states, "ah as in father" and "oh as in bone". The only other place it occurs is in the digraphs ch, sh, th, dh, which you don't seem to mind. kwami 00:40, 2005 May 23 (UTC)

As a physicist/astronomer by vocation, and a linguist/phoneticist by avocation, I must say that the current pronunciation guides as is are now quite worthless to both fields. Anyone who would remove the h from the standard digraphs ah and oh clearly doesn't know what they're talking about and has no business making changes to pages. Please restore the page back to useful pronunciations, or I'd recommend simply removing all pronunciations to the individual pages on each moon. As fascinating as it is to the linguist side of me, the astronomer/taxonomy side of me points out it's the classic Emerson/Asimov/et al "hobgoblin of small minds" situation all over again. And for reference to MPF: ah, eh, ih, oh, and uh have unambiguous meanings in English transliteration. They're clearly the a as in father, short e as in met, short i as in fin, long o as in boat, and short u as in cut. Putting oe in as has been done is absurd. Is it the oe in toe or the oe in shoe or the oe in Schroedinger or the oe in poet or ...? sturmde 2005 June 3

satellite masses
Do we really need those mass approximations? Even the radii of the new small irregular satellites are very poorly known, let alone their densities. Only the Galilean satellites and the small inner satellites have their masses measured. --Jyril 12:36, Mar 25, 2005 (UTC)
 * Alright, found this . Authoritative enough for me. --Jyril 19:03, Mar 25, 2005 (UTC)

Latest batch of named moons
I gotta ask, just in case someone knows.. where did the latest bunch of named moons come from? It almost seems like they picked ten moons out of a hat to give names to... especially the way they gave a less dynamically interesting moon with a not-very-well determined orbit like Thelxinoe (formerly S/2003 J 22), and yet didn't name the interestingly seperate, far-flung and more well known S/2003 J 2. I'm glad that some deserving moons got names (especially Carpo, and it was time for Arche), but.. I digress. And am not even going to touch upon S/2001 J 11. Anyway, does anyone know what the IAU is thinking? Sorry for the rant.. --Patteroast 10:59, 2 Apr 2005 (UTC)


 * According to the "Recently Discovered Natural Satellites of Major and Minor Planets" section on this page, new designations and names have been announced in the IAUC circular #8502 (only available to subscribers). All the named satellites can be found here. Since the last check there are ten new names, so I suppose they are the moons announced in the circular.
 * And how do you know they are more well known? Moons are named after their orbits are known sufficiently well. Too bad there seems to be no up-to-date list of observation arcs for the moons, so can't say which of them have well established orbits (except for the named ones, of course).--Jyril 13:21, Apr 2, 2005 (UTC)
 * Note: IAUCs currently stop at 8499, so 8502 should be accessible "soon". 03:45, 27 November 2006 (UTC)
 * Ah.. I didn't think about the unreleased observations. I suppose since the last news was heard, these moons have been observed more intensely than they had been previously. I was just curious, because as of the last observations that I had found online, some of the newly named ones had very uncertain information. Sorry for ranting about it, but I try to keep myself informed, and it just seemed like an odd pick. I guess the way they named nice orderly groups of Jupiter's moons previously (all of 2001's at once, and the first ten of 2000's at once) made it seem odd to jump around at this point.
 * Still, I want to know what's going on with S/2001 J 11. Did it explode, or what? :P --Patteroast 09:49, 3 Apr 2005 (UTC)

Orbital period in the table.
Is the orbital period unit - day - is a day of the Jupiter or a day as counted on Earth (i.e., 24 hours) ?

Thanks rraghav


 * It is very rare for the unit of time "day" to mean anything but 86,400 seconds. When that happens, the word is properly qualified (e.g. "lunar day", "martian day", etc.).
 * Urhixidur 01:55, 2005 Apr 15 (UTC)

Kepler's third law saved
Because we relied on the JPL Solar System Dynamics pages, we had some very odd things going on with the irregular moons of Jupiter and Saturn. Specifically, we had strong violations of Kepler's third law. Now that I've found the IAU-MPC Natural Satellites Ephemeris Service, it has become clear the solar perturbation "explanation" doesn't wash. The ephemeris generated respect Kepler's third law down to five decimal places. I'll shortly use these more reliable values to update the tables.

Urhixidur 12:59, 2005 May 6 (UTC)


 * Well, the orbits of the irregulars are not Keplerian (i.e. highly perturbed; 3- and not 2-body approach is needed) and JPL provides the mean elements from the integrations. Of course, our Moon’s orbit is not Keplerian either. If you take the ephemeris (they are Keplerian) the orbit will look very different in less than a year. I was surprised to read that for Pasiphea for example, (osculating) semimajor axis can change as much as 1 Gm in as little as 2 years, the inclination around 5 degrees and the eccentricity as much as 0.5 in some 25 years! Consequently, when the ephemeris are needed to locate the sat in a given moment in time, mean orbital elements are more suitable for most other uses (e.g. grouping the sats). Eurocommuter 14:31, 6 September 2006 (UTC)

Column "Mass"
It seems that the masses (at least for Galilean satellites) are by factor 10 in error. Cf. eg. http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jup_Ganymede&Display=Facts. Also recalculating from GM parameters (obtained from Galileo probe tracking), leads to the ten times greater values for recomputed M. (See http://ssd.jpl.nasa.gov/sat_props.html ). I am in process to correct the similar table on Czech Wiki.

cs:avitek / avitek@lib.cas.cz


 * Besides the fact the http://solarsystem.nasa.gov/planets/profile.cfm pages are rife with errors, you rightly spotted the errors. All of the masses were off by a factor of 10!
 * Digging in the history, I see I'm the culprit. The error was introduced on 10:14, 2004 Aug 7. Obviously I must have botched up the number formatting with Excel. Probably those damn commas vs periods. My apologies, it's all fixed now!
 * Urhixidur 03:15, 2005 Jun 4 (UTC)

highlighting
I'm highlighting the moons of the gas giants according to the following criteria: Lunar sized (Galileans, Titan, Triton) bold name in a medium voilet background (style="background:#ccccff";); smaller spheroidal moons (Saturn & Uranus) bold name in a lavender background (style="background:#eeeeff"); irregular moons not bold and on a white background.

I expect that some of you will object to these categories, and perhaps something else would be better. My idea was that the lunar-size category is one of general human interest, and the spheroidal/irregular distinction is relatively objective and is found frequently in the scientific literature. Especially in the case of Saturn, I think it's important to do something to make the tables more visually accessible and to make the 'main' moons easier to find. They're getting too big to easily navigate. kwami 05:50, 7 October 2005 (UTC)


 * Hi Kwami, I like this idea and it works well. I think we need an explanation at the top of the table, because the phrase 'Spheroidal moons in bold' is easily overlooked in its current location. Also, I think 'planet-sized moons' is a better term than 'lunar-sized'. Other than that, I think it's great. The Singing Badger 16:33, 7 October 2005 (UTC)


 * I agree as well. The Galilean moons are so different from the rest of Jupiter's satellites they should be highlighted. Dralwik 23:41, 19 January 2006 (UTC)

Retrograde orbits
Some of the moons are listed with orbital inclinations greater than 90&deg;. For consistency with the pages listing other gas giants' moons, it might be an idea to subtract the inclination from 180, and give the orbital period as a negative number. CS Miller 12:41, 19 October 2005 (UTC)

The moon navigator
I've updated all moon navigators for Jupiter's moons, rearranged them by the moons' roman numerals and designations, which is widely used in astronomical community to order both moons and asteroids. And I suggest the data sheet on this article rearranges by roman numerals too. — Yaohua2000 22:47, 4 March 2006 (UTC)
 * Hi dude, it might have been a good idea to discuss this first before doing so much work. I personally dislike the idea of arranging them by roman numeral - the roman numerals don't reflect size, distance from Jupiter, discovery date or anything at all, so arranging them that way produces a meaningless list that doesn't tell the user anything about the nature of the moons. I'm not very happy with this change but by all means try to persuade me. The Singing Badger 00:13, 5 March 2006 (UTC)
 * Since you can only apply one order in the navigator, for size, distance, and etc, it is not easy to say to choose one or not choose the other. The roman numerals is widely used in astronomical community, and it generally reflects the distance to the planet (for early discovered moons) and discovery date (for later, with some exceptions). — Yaohua2000 00:19, 5 March 2006 (UTC)
 * I guess that's true. I don't care enough about this to start altering your changes, but I'd suggest that you consider pausing in your work to at least post the idea for discussion - if somebody with more energy than me started changing things back again you'd be very annoyed...! But anyway, while I would strongly disagree with doing the same thing to the data sheet on this article, I agree that it doesn't matter so much for the navigator. The Singing Badger 00:30, 5 March 2006 (UTC)
 * I'd say go with the distance. It seems to be the most natural way to order them, at least to me. I also agree with not liking the Roman Numeral ordering.. it may be useful for some of the earlier moons, but for the majority of new ones, tells you nothing. --Patteroast 00:56, 5 March 2006 (UTC)
 * The roman numerals for moons just like the numerals for asteroids, which is the natural way to order moons. Can't imagine ordering asteroids by their distance to the Sun. — Yaohua2000 01:17, 5 March 2006 (UTC)


 * Why not order them alphabetically then? It's usual to order moons by semimajor axis. This gives people the impression of navigating through a planetary system rather than through an arbitrary list. If the asteroids formed a single coherent system we'd arrange them by distance too. Where I sympathize with Yaohua is with the irregular moons, since many are very close to each other in distance and ordering by distance obscures their family relationship. But it would have been polite to discuss this first.


 * How about a show of hands: Does anyone support Yaohua with this change? kwami 01:52, 5 March 2006 (UTC)


 * Found your explanation! It's a bad one I think, but I'll stop reverting your changes at Harpalyke (moon) until this is resolved. --Yooden
 * Wikipedia is not a resource for the astronomical community, but for the general public.
 * The common pattern to name things in space after date of discovery makes sense because you can't constantly rename things if you find new ones. Wikipedia does not have this restriction, inserting a new satellite is easy to do.
 * A pointer to this discussion in one (or even every third or so) of the changes would have saved one of us a lot of work. --Yooden


 * OK, if you do not agree with me, you can revert the all, but please do not revert some and leaves others. And I strong suggest you here reconsider my suggestion, while this arrangement used in academic, and suggested by IAU. And also, I don't find any benefits in arrange the moons by the distance from their planets, I can't find a moon much easier with this order than another, so why not arrange by a academic one? — Yaohua2000 17:31, 5 March 2006 (UTC)


 * I'm strongly against sorting the moons by number or discovery time. In the case of asteroids that is obviously the best way, but I don't think it's good idea with the moons of Jupiter. Casual reader may have hard time to understand why for example Thebe comes after Leda. Current scheme is much more obvious, although it may be somewhat ambiguous with small outer satellites that don't have well-defined orbits.--Jyril 17:41, 5 March 2006 (UTC)
 * If a reader don't understand about this arrangement, we can add a line to tell them what it is. It is not something difficult to understand. And it took me some while to understand the arrangement you suggest. Another reason is that, if you arrange the moons by their number, you can find the first of few moons are all large and signifiant, our probes usually do more things on the first of few moons, and we know much more about the first ones than others, so this arrangement is not only an order by discovery date, but also (nearly) by their size and mass. — Yaohua2000 17:51, 5 March 2006 (UTC)


 * Yes, there are some benefits, but when kids learn the moons, they learn them (or a subset of them) by distance, just as they do the planets. What say we leave this for a few days so more people have a chance to comment? kwami 21:14, 5 March 2006 (UTC)


 * However, you cannot expect kids learn asteroids by distance. It seems most of you here do not familiar with numeral designations for moons, so why Titan, the largest, and the earliest discovered moon of Saturn designated as Saturn VI? Just because it is the 6th large moon from Saturn by distance, after Mimas, Enceladus, Tethys, Dione and Rhea, so if you read more about the numerals, you may find it is actually a very good sorting, like planets, in numeral designations, large moons discovered before 20th century are arranged by distance, those small and icy rocks discovered in space era are arranged by discovered date, just like planets and asteroids, those large moons are planets, so we arrange them by their distance from the central body, and those small and icy moons are asteroids, we arrange them by their discover date. It is difficult to recognize which moon is more interesting and significant if mixing those rocks with giant moons, that is also why we have to use color to highlight those large moons in the table at this time. — Yaohua2000 06:50, 7 March 2006 (UTC)


 * There's nothing barring us from using different systems for the moons and the asteroids. Myself, I prefer presenting the moons in a way that reflects some natural ordering. The most obvious choice to me is distance from the primary. This tends towards unwieldy with Jupiter's outer moons, but I don't feel it is any less helpful than Roman numerals in that case. For the inner moons, distance ordering seems to work just fine. Either way, this seems to be a matter of opinion above anything else. I simply prefer distance ordering. --Patteroast 11:15, 7 March 2006 (UTC)


 * OK, let's try asking this question: what are the 'moon navigators' actually for? Their name is misleading since they are in fact not very useful for navigation. If a user is looking at the article for one moon, the 'moon navigator' only gives them a choice of two other moons to jump to. So if a user is trying to do something specific, such as look at the articles for six or seven specific moons, they will use the template at the bottom, not the 'moon navigator'. The 'moon navigator' is only useful for the curious reader who might think "hey, let's look at the next moon, what the hell!" What this means is that the 'moon navigator' is only a useful educational tool if it gives you a sense of order; for example, by taking you on a journey through a system. That sense of a journey is, I think, more valuable if one is actually travelling through the system by distance, from the inner moons to the outer, and not if one is sometimes going by distance, sometimes by discovery date, and sometimes by no particular order.
 * The reason this argument doesn't apply to the asteroids is simply that there are tens of thousands of asteroids but only 60-odd Jovian moons. A person can do the 'Jupiter tour' in a few minutes if they want to. It would take forever with the asteroids. The Singing Badger 12:58, 7 March 2006 (UTC)
 * Yes, you can. At school I learned a mnemonic to learn the planets by distance ("Mein Vater erklärt mit jeden Sonntag unsere neun Planeten", Every Sunday, my father explains our nine planets to me). Why should it be different with moons?
 * Indeed, and in a few years they may come up with yet another way to name the buggers. This is all subject to change, while the distance from the main body is not. --Yooden
 * Ok, I went back to the earlier order. Please check the changes, I tried to avoid reverting unrelated changes, but Yaohua2000 not using summaries didn't help. --Yooden

Curiosity of phraseology
"Jupiter has 63 known natural satellites." -- Does this imply that there are non-natural satellites, and if so, what is the citation ? -- Simon Cursitor
 * Well, it did when Galileo was in orbit. Natural satellite is the scientific term for moons, so it's just saying that we currently know of 63 moons orbitting Jupiter. --Patteroast 15:49, 25 August 2006 (UTC)

Accurate sources for orbital data
(I already posted this in the talk section for Themisto, but I think people might not notice it there).

When looking at the orbital elements for Themisto (and some other satellites), I can see large contradictions.

For example, for the semi-major axis of Themisto, gives 7.507 Mkm,  gives 7.284 Mkm, and this page gives yet another. Which sources are more accurate? JamesFox 21:23, 7 September 2006 (UTC)


 * Never mind. After a while, I've decided that the IAU-MPC Natural Satellites Ephemeris Service is probably the best bet for irregular satellites. JamesFox 11:07, 11 September 2006 (UTC)


 * I’m sorry, I did not read your message here earlier. It is a bit more complicated, I’m afraid. I suggest mean orbital elements instead. Please see my response to User talk:Deuar for example. Discussion remains open, of course. Eurocommuter 12:01, 11 September 2006 (UTC)


 * Thanks for the response. I didn't realize that the orbits changed that quickly. Incidentally, I'm wondering if this means it might make more sense to order irregulars by group rather than by SMA in the Wikipedia tables. JamesFox 17:49, 11 September 2006 (UTC)


 * James, you should realise that "Mkm" is considered an atrocity against SI. The correct symbol is Gm. :-)
 * Urhixidur 17:52, 11 September 2006 (UTC)


 * It is indeed the idea Urhixidur is playing with for navigators (see project page). The problem then is that classification into groups (except for tight groups like Carme) is a bit controversial as well (many member are fringe members, some cluster into two etc.). I would say let’s use mean orbital elements but give the group the precedence (i.e. avoid mixing moons from different inclinations just because of SMA and add a graph illustrating the elements (sample graph). Eurocommuter 18:14, 11 September 2006 (UTC)


 * Might I suggest that instead of entering the mean semi-major axis, in those cases where the size of the orbit changes drastically there be entered a range instead? RandomCritic 14:03, 22 September 2006 (UTC)


 * For all the moons between S/2003 J12 and Megaclite, there's a total discrepancy between the data here and that at Scott Sheppard's site. The only thing they have in common is that the group of satellites from Thelxinoe to Mneme is separate from that going from S/2003 J 17 to Megaclite.  Otherwise, there's neither agreement in the absolute or the relative spacing of the objects.  An enumeration of objects by distance based on Sheppard's data would be totally different from one based on the data here.  What gives?  If it's true that the orbits are variable, shouldn't that be reflected in the data rather than implying that there's a fixed order? RandomCritic 18:12, 22 September 2006 (UTC)
 * Sheppard page (not necessarily kept to date) is based on Jacobson data (JPL) but often earlier that the ones used on JPL page. BTW, not all outer moons have the orbits as wildly changing as Pasiphae. The order based on the mean semi-major axis seems to me a reasonable choice. It is more or less fixed (the elements are calculated on 1000 years+. Given that the identification of the groups is based on the mean elements I believe they are the most representative for this table. Eurocommuter 20:31, 22 September 2006 (UTC)
 * I tried following the links, but could not find JPL data that agreed with the data on this page. A search of my own turned up this JPL page, but the data here again disagrees. RandomCritic 22:57, 22 September 2006 (UTC)
 * Okay, now I see that these are the sources that were discussed above. Sorry.  Would it be possible to have a column listing current values beside the mean values, and updating them periodically - say once a year?  I think that information, if we could get it, would have very high instructive value. RandomCritic 01:14, 23 September 2006 (UTC)
 * I finally found the NSES data, and converted it from AU to km and double checked the numbers -- evidently the numbers have all been updated, because while in most cases the numbers were pretty close, in some cases they were wildly different and in all cases they were at least slightly different. Shall I go ahead and update the table? RandomCritic 04:33, 23 September 2006 (UTC)


 * Updated the table based on the latest NSES data for semi-major axis and period, and re-ordered based on that data. Moons that moved included Ananke, Mneme, Carme, Callirrhoe, Pasithee, Pasiphae.  I have pretty high confidence that I entered the data correctly, but feel free to double-check it.  I have not yet updated inclinations and eccentricities, though some of those numbers may need to be changed as well. RandomCritic 16:31, 23 September 2006 (UTC)
 * What's the relationship between the NSES data on inclination and the numbers given here? I just went through a comparison of the two, and in most cases the numbers are totally different -- there's a bunch of moons given inclinations of over 160°, and there aren't any with such high inclinations in the list. RandomCritic 23:32, 23 September 2006 (UTC)
 * After comparing several tables, I decided that the numbers on this page are just wrong. So I have gone ahead and entered the NSES data.  I also updated the eccentricities -- for the most part, the differences there were trivial (probably amounting to no more than differences in rounding) with the exception of the following moons: Leda, Himalia, Lysithea, Elara, Mneme, Ananke, Carme, Callirrhoe, Pasiphae, Carme, Sinope, and S/2003 J14. RandomCritic 12:52, 24 September 2006 (UTC)
 * I suggest using Jacobson mean orbital data (JPL) data, at least for the irregular satellites, as they are the most used in the literature. If you wished to use (and update regularly the osculating elements, the IAU data are the most used. We also suggested on one of talk pages, that an extra column could be added specified the source.


 * Ephemeris from IAU
 * Mean orbital parameters from JPL
 * My apologies for infrequent visits on these pages recently. Eurocommuter 16:54, 24 September 2006 (UTC)

Inclination
As in every gas giant satellite page, there seems to be quite serious problems with the inclination values presented here. Take Themisto, for example. The table says 45.762° while the Themisto (moon) page says 13.865°. At the same time, the Themisto page says that the inclination is 45.81° when measured relative to the eclyptic rather then Jupiter's equator. The source in the table is supposed to be the IAU-MPC Satellites Ephemeris Service. Could it be possible that this service delivers inclination data relative to the eclyptic? Does anybody know? It would mean that all the incination data in the tabe for the irregular moons is wrong. Krystman 22:07, 26 November 2006 (UTC)


 * Blame RandomCritic, I guess. I'll have to go over the table again some time in the future, and probably include comments within the table to avoid further such damage.
 * Urhixidur 03:55, 27 November 2006 (UTC)


 * But wait, something is fishy here. How can there be such huge difference in the equatorial inclination vs. eclyptic inclination of Themisto (13.856° vs. 45.81°) if Jupiter itself has an orbtal inclination of only 1.305° and an axial tilt of 3.13°? The equatorial inclination of Themisto should be no more appart from the eclyptic inclination then 4.4°. However, based on Urhixidur's calculations it is more then 30°. How come?
 * Krystman 14:33, 27 November 2006 (UTC)


 * Themisto is inclined 45.805° to the ecliptic (source: NSES), 24.716° to Earth's equator, 13.865° to Jupiter's equator, and 15.346° to Jupiter's orbit, according to my calculations. Hmmm, you're right, something is wrong. Urhixidur 03:14, 28 November 2006 (UTC)
 * Ah, I know what it was! It's those damn ambiguities in acos and asin. Luckily, there is only one ambiguity, because codeclinations cannot be negative; the ambiguity in delta-alpha (the difference in RA) can be lifted because the law of cosines gives us a third equation that must simultaneously be satisfied. I'll work that into the spreadsheet and recompute the angles shortly. Urhixidur 04:36, 28 November 2006 (UTC)


 * These outer satellites are pulled around by many actors, and reference "planes" (scare quotes, because it isn't flat) are defined dynamically, not geometrically.  See http://ssd.jpl.nasa.gov/?glossary&term=lp and http://ssd.jpl.nasa.gov/?sat_elem for details.  Basically, the problem is that the inclination is not to the equator, but the inclination to the local Laplace plane:  the column title in the table is wrong.  mdf 16:00, 27 November 2006 (UTC)


 * That's because the inclinations were put in with respect to Jupiter's equator in the past, but were later changed to the NSES ecliptic inclinations later, without updating the column title. We could use the JPL mean orbits, but those data are confusingly reported in a variety of frames, in addition to being incomplete (several moons are missing). Urhixidur 03:14, 28 November 2006 (UTC)

Leda diameter
This was corrected from 20 to 10; I can find figures anywhere in the 10-20 km spread, but I don't know which is the latest. The Leda (moon) article still uses the 20km figure. RandomCritic 23:19, 6 December 2006 (UTC)

pronunciation
The IPA used in the table probably shouldn't be in italics. It looks like crap. --24.11.177.133 15:31, 12 December 2006 (UTC)
 * Changed the italics to brackets. --24.11.177.133 16:12, 12 December 2006 (UTC)

Roman numerals
What are those Roman Numeral designators called anyway? They are currently under the "name" heading in the table, which seems wrong. --Yath 04:19, 20 January 2007 (UTC)

IPA
User:Kwamikagami made a large number of changes to the IPA representation of the pronunciation of the names of these moons; some changes defensible, but many not. I am creating this section in case (s)he or anyone else wants to discuss the representations (and the pronunciation itself). However, I have reverted the changes as I believe that they are, overall, detrimental to the use of the IPA as a system to determine how to actually pronounce the names in English; there are other errors, too. I should like to stress that there is a system to the English pronunciation; pronunciations are not randomly assigned at whim. RandomCritic 15:58, 8 May 2007 (UTC)
 * The use of the superscript h to show aspiration is silly, in my opinion. I've never seen it used in an English dictionary.--Cam 16:06, 8 May 2007 (UTC)
 * There's a reasonable case for not including it based on redundancy -- but the "English dictionary" comparison obviously raises the question of who these representations are for: people who already speak English and are familiar with English phonology? People who are less familiar with English conventions?  Linguists?  Non-linguists?  If English speakers, then speakers of which dialect?  How much knowledge, outside of the values of the IPA symbols themselves, do you expect of the reader?
 * There are a variety of broader and narrower transcriptions possible, and since in most cases (the names of Greek and Roman origin) the pronunciation is a direct reflection of the spelling, and so -- given enough rules (quite a lot of rules, in fact) you could get by with indicating nothing more than the position of the primary accent, and sometimes even that would be superfluous. RandomCritic 16:21, 8 May 2007 (UTC)


 * Well, to get the proper stress you need to know which vowels are long in Latin, which we don't provide.
 * Sometimes. Penultimate closed syllables are predictably stressed regardless of vowel length. Penultimate syllables containing diphthongs are also predictably stressed.  The absolute minimum indication would be a mark (indicating stress, or length, as you please) on simple vowels of open penultimate syllables.  Everything else can be figured from that; but the rules are, as I said, not simple; they're reasonably straightforward, but there are a lot of them.RandomCritic 17:13, 8 May 2007 (UTC)
 * Also, there are some irregularities as to which vowels are reduced.
 * There is dialectal variation. Not so much irregularity.  There are occasional lexical exceptions for some of the most common names (e.g. Hyperion).RandomCritic 17:13, 8 May 2007 (UTC)
 * But the point of a pronunciation guide is to guide those who are not familiar with the pronunciation - sure, if you've been trained in the classics, it may not be necessary, but we're considering the public at large. In any case, an increasing number of names are not Greco-Latin.
 * I agree. But the last point is even more touchy, as there is no common tradition for Anglicizing names from, say, Norse: you're left with a decision as to whether to base the pronunciation on the Norse of the First Grammatical Treatise, or on Modern Icelandic, and in both cases wondering just how far to adapt it to English pronunciation norms.  My inclination is to go with Modern Icelandic and adapt as little as possible.RandomCritic 17:13, 8 May 2007 (UTC)
 * I would appreciate it if you would moderate such a discussion. As far as adapting it to English, it would need to conform to English phonotactics, though we could always give the Icelandic pronunciation as well. kwami
 * Also, I feel the IPA should be a guide to the native speaker. Anyone else reading this article should know that most dialects of English aspirate p, t, k, ch in certain positions; the average native speaker can't hear that and will only be confused. There's been a lot of argument as to whether we should use the IPA or pronunciation respellings; one of the objections to the IPA is its complexity and unfamiliarity to many English speakers (at least in the US, where most people are clueless as to what it is), so I don't see how adding phonetic detail helps. But in any case the errors I corrected, such as Thelxinoe (the x is pronounced as /z/, not /ks/), should be preserved. kwami 16:49, 8 May 2007 (UTC)
 * On "Thelxinoe", I do not know where you got the idea -- I assume some handbook -- but it's a mistake. Thelxinoe is from θελξις; the x has never been initial.RandomCritic 16:56, 8 May 2007 (UTC)
 * By way of comparison (with rx, rather than lx, since lx is quite a rare combination) -- the correct pronunciation of Xerxes in English is [ˈzɝk.siz], not [ˈzɝ.ziz]. It's true that it's at the beginning of a stressed syllable, but that makes no difference elsewhere; voicing of [ks] to [gz] does occur in this position, but practically only with the prefix ex-. —The preceding unsigned comment was added by RandomCritic (talk • contribs) 17:04, 8 May 2007 (UTC).
 *  is a poor comparison, since /r/ and /l/ behave quite differently in English, but then there's , so I'll drop this one. kwami
 * I could see the diphthongal representation of the long mid vowels, that's pretty common, if arbitrary. But what do you object to? The IPA shouldn't represent any one dialect, so it should be as broad as possible: inverted ar and aspiration need to go. Syllabification is not phonemic in English, so we can drop that altogether, but as it is now it is not English. I corrected several errors, too, so I intend to restore my changes unless you can explain what you object to and why. kwami 16:18, 8 May 2007 (UTC)
 * I intend to explain my objections, but give me a few minutes! RandomCritic 16:21, 8 May 2007 (UTC)


 * In the most widely used dialects of modern English, what used to be /oː/ and /eː/ are now diphthongal, and that is in fact what is distinctive about them. The quality of the vowel can vary a great deal ([ɔu], [ʌu], [ɞu], [əu], very rarely [ou]; [ei], [ɛi], [æi]) but in all cases it's the diphthongal quality that's distinctive.  This indicates that the underlying vowels are (now) diphthongs, not monophthongs. Writing these diphthongs with final ɪ and ʊ is conventional, but now reflects a minority pronunciation.
 * As I said, I'm willing to accept that. kwami
 * [ɹ] vs. [r]. The former is the sound used by most English speakers.  The latter is used by some Scots.  With all respect to speakers of Scots English, it's not a dominant type of pronunciation.  I know that some people who have tried to simplify IPA for English have used [r] for [ɹ], as a more recognizable symbol, but that's in fact incorrect.
 * How "incorrect"? You could use a baseball - this is a phonemic representation, not phonetic, despite the brackets (which should also be corrected). It is standard to use  for the English rhotic, as e.g. in the OED. The only time <ɹ> is used is when showing dialectical distinctions, which is precisely what we are not doing. So no, if you want <ɹ>, you're going to have to convince a lot of people. kwami
 * Syllabification and aspiration. To some extent these are redundant, as aspiration occurs on voiceless stops syllable-initially, but they are significant and you can't get rid of both of them.  If you wanted to get rid of one, aspiration is the better target.  As the Greek names often have weird vowel sequences that are unusual in English (e.g. [i.i]), using syllable breaks helps enormously to clarify the pronunciation.
 * Okay, I'll keep the syllabification and drop the aspiration. kwami
 * Some of the pronunciation "corrected" were just wrong. They may be listed as such in some handbook or other, but if so, the handbook is wrong.  There are rules governing pronunciation; these are not prescribed by the IAU but by historical norms of English pronunciation of Latin, a matter for which there is at least four centuries of detailed paper trail.  By those norms, x is pronounced [z] at the beginning of a word, but it is never so pronounced word-internally, but always [ks] (in very limited circumstances [gz]).  Thelxinoe cannot be pronounced [θɛlˈzɪ.nəu.i] under any dispensation; that is just wrong.
 * Since this may be a unique case (there is no  in any word in the OED, apart from some old French plurals), I don't see how you could say the rule applies here - it could as easily be an exception as in the case of /gz/, and might be expected to be, though since I can't support my opinion I'll drop it. kwami
 * Aitne likewise. If the people who chose the name had chosen to use the spelling "Aetne", then yes, it would be pronounced [ˈɛt.ni]; but since they chose the spelling "ai", as a matter of rule, it has to be pronounced [ei] in English.
 * My objection here is that it's in a closed syllable, which generally shortens vowels in English, but I'm willing to drop this one as well. kwami
 * Naiad, by rule should be [ˈnei.əd], and is in some varieties of English, but by some speakers the common noun is [ˈnai.æd] and the pronunciation is carried over to the name of the moon.

RandomCritic 16:51, 8 May 2007 (UTC)
 * Shouldn't it be [ˈnai.æd] because of the diaresis on the i? kwami 17:43, 8 May 2007 (UTC)
 * No. In principle the diæresis would indicate an additional syllable, but in practice the diæresis, especially over a following i, was generally disregarded.  Even if the additional syllable were pronounced, by the rule under which all vowels, except for unstressed i, e, and y, become long before another vowel, the pronunciation would be [ˈnei.i.əd]. RandomCritic 13:18, 16 May 2007 (UTC)

Father-bother unmerged
I've taken the liberty of changing the pronunciation shown for certain moons which are listed here, and on the equivalent pages for Saturn and Uranus in order to avoid the father-bother merger that occurs in General American and was heretofore reflected in the IPA. The change in question is from the vowel <> (i.e. the "father" vowel) to the vowel <> (the "bother" vowel), and affects the Jovian moons Isonoe, Sponde & Autonoe, the Saturnian moon Polydeuces, and the Uranian moons Rosalind, Oberon & Prospero. I checked the individual pages for the moons themselves and all except Polydeuces (which I've now changed) already made the distinction. In tandem with this change, I've corrected the instances of  to <> in the Saturnian moons Skathi & Kari and the Uranian moon Margaret, as it would appear that the IPA transcription used here does not use  for this English vowel. Note also the further related change to Oberon's pronunciation, to ensure that the  is shown as pronounced, even in non-rhotic dialects.

Having gone through all the moon pronunciations on these pages, I do have a few more concerns that I'm hesitant to alter at this stage, though. The first is with the representation of <> for the stressed vowel in the Neptunian Nereid, Saturnian Hyperion and Jovian Callirrhoe, as this seems to be reflecting the mirror-nearer merger - changing this sequence to <> may correct this (or introduce new problems?). (A minor question in addition to this: is that really the stress pattern for Callirrhoe? - I find it quite difficult to pronounce as is.) The second is with the first vowel in the Saturnian Paaliaq - is <>, the vowel in "not", really intended there (i.e. does it really have an identical first syllable to Polydeuces in all accents)? And finally, the pronunciation for Ariel given on the Uranian moon page (but not the moon's page itself) seems to suffer from the Mary-merry merger. Thylacoleo 05:07, 6 June 2007 (UTC)


 * I'm afraid what you've done - from my point of view - is not avoid the "father-bother" merger, but afflicted the pronunciations with the cot-caught merger. I don't think most Americans use a clearly rounded vowel (i.e. ) for the "short o" sound -- for me it is the sound in "naught", not "knot". Some Britons may use this sound, however.
 * As far as I am personally concerned, the vowel "e" in Nereid and Hyperion could be [i], while the "i" in Callirrhoe must be [ɪ], but I may be in the minority; for many speakers, [i] is laxed before [ɹiV] (as it is, generally, in words like "cereal" and "serious"). This isn't the same as the "mirror-nearer" merger, as it goes in the opposite direction.
 * With regard to the Inuit names, I suggest consulting Inuit_language_phonology_and_phonetics, though I imagine the different dialects instantiate the phonemes variably.
 * The pronunciation of Ariel has nothing to do with "Mary-merry" merger, but rather historical changes in quantity and quality of "a" before an unstressed prevocalic i or e; i.e., one expects the a in Ariel to have the same value as the first a in "area", however one chooses pronounces that.
 * The correct stress for "Callirrhoe" is on the antepenultimate syllable, as the vowel in the penultimate syllable is short in Latin & Greek.
 * Oberon got represented incorrectly sometime in the last batch of revisions (which I was not involved with). There are quite a few bad syllable divisions now present, which I haven't had the time to correct. RandomCritic 07:08, 6 June 2007 (UTC)


 * I possess neither the father-bother merger nor the cot-caught merger myself - in order to keep the transcription as dialect-neutral as possible all three vowels need to be kept distinct. Looking through what has already been done here and elsewhere in Wikipedia, it would appear that the system used to achieve this is a compromise one which uses for the father vowel (inspired by RP and GA),  for the bother/cot vowel (from RP) and  for the caught vowel (from RP and GA) - none with length marks. I'm a tad confused by your description of your pronunciation as "naught" rather than "not" - do you mean that in your dialect the first two vowels in Autonoe, for instance, are identical (something like [])? I would have assumed the pronunciation to parallel the word "autonomy" instead. If the former is the case, however, I'm unsure how that could be accommodated in the scheme.
 * No, around here (American midwest, but typical of much non-Southern American speech) "short o" (in knot) and "au" (in naught) are distinct, but the one is and the other is, while the "a" in "father" is low-mid, either , or, more likely, just  with a diacritic marking additional fronting.   exists, but only in words like "north" and "toy", where it is notably higher than the "au" in "naught".  And "short o" is in fact so far from being  that for many midwestern speakers it is fronting towards [a]. (This does tend to produce a father-bother merger, but more in the direction bother rhyming with father than the other way around).RandomCritic 04:45, 7 June 2007 (UTC)
 * (Response given below. Thylacoleo 05:50, 7 June 2007 (UTC))
 * I was uncertain regarding the facts in the Hyperion case (which is why I haven't changed anything yet), and agree that whereas Hyperion and Nereid should have the tense vowel ( - without the length mark, should suffice), the spelling of Callirrhoe suggests that it has the lax vowel instead (I've never heard it pronounced). I'll take your word for the stress pattern.
 * The i in Callirrhoe should definitely be lax. RandomCritic 04:45, 7 June 2007 (UTC)
 * As for Ariel, I agree it would be pronounced in the same manner as "area", but the current rendition (as ) is claiming that it is instead pronounced similarly to "terrier", which is patently not the case.
 * I agree.RandomCritic 04:45, 7 June 2007 (UTC)
 * I had a look at the Inuit phonology page, which suggests that the first vowel in Paaliaq would be pronounced as . According to the transcription scheme being used for "neutral-dialect" English here, this would be rendered as, although if the length of the vowel were considered important, I suppose could be chosen instead. In either case,  would be inappropriate. (In the interests of full disclosure, my own native dialect is Australian English, but affected by the salary-celery merger.) Thylacoleo 01:45, 7 June 2007 (UTC)
 * I see. It would appear we've run into the problem of phonetic realisations shifting ground confusingly under the overlying phonemic structure, creating a mismatch with the standard phonological representations. My own dialect (Standard Australian), has undergone similar shifts, but sometimes in different directions - the father vowel is realised [] (or possibly []), the bother/cot vowel is realised [], and the caught/north vowel as [] (no rhotic in "north", of course). At least we agree that three distinct phonemes are involved, and each will need a different symbol. The choice of, , and respectively, while running roughshod over the phonetic peculiarities of both our dialects, does appear to suit GA and RP reasonably well without unnecessarily merging any phonemes, which is why I used it. On the other matters, as we agree, I'll make the suggested changes to Nereid, Hyperion and Ariel (but not Callirrhoe, which is already correctly rendered following from our discussion), and (pre-emptively) alter the first vowel of Paaliaq to  - in the current system the length mark wouldn't ordinarily be used, but from what I've read of lay descriptions of the intended pronunciation, the vowel's longer status is considered important. Thylacoleo 05:50, 7 June 2007 (UTC)
 * I went in and fixed the syllabification, some schwas that had been replaced by i, and some inconsistencies in which symbol to use for schwa. I'm afraid I may have screwed up some vowels which I merge (e.g. Ariel - I merge a lot of them!), so please correct as needed. It wasn't intentional. kwami 17:53, 6 September 2007 (UTC)

Additions to "See also"

 * The navigation boxes at bottom were created specifically to avoid having lengthy and repetitive "see alsos" under the name of each planet. What's the argument for doubling the information from the navboxes under "See also"? RandomCritic 13:14, 16 May 2007 (UTC)
 * A question that can be best answered by Urhixidur, who has added them to this and the other moons pages. The links to the other moons pages are indeed redundant, being adequately covered in the navigation box, while Galilean moons is twice linked to in the article itself. Jupiter's moons in fiction does not appear to be linked to elsewhere, however. If you want to eliminate the See Also section altogether (which I would support), I would suggest incorporating a reference to that last one in the article text itself (perhaps in an appropriately expanded lead?). Thylacoleo 04:25, 7 June 2007 (UTC)

"Moons of Jupiter"
There has been consensus to change the name of the Uranus' natural satellites article to "Moons of Uranus" here. This fits the footer, is less jargony, and avoids the apostrophe issue some people complain about with Uranus and Mars. However, this article should have the same format. Anyone here wish to comment, support, or object? kwami 19:36, 13 October 2007 (UTC)


 * I would approve of "Jovian moons" myself, but given that all of the forms of these names mean exactly the same thing, isn't the best thing to do just to leave them alone? RandomCritic 19:50, 13 October 2007 (UTC)


 * See the discussion at Uranus' natural satellites, which was triggered by people objecting that the title was orthographically incorrect. kwami 20:52, 13 October 2007 (UTC)
 * (Actually, I like "Jovian moons" too. kwami) —Preceding signed but undated comment was added at 20:53, 13 October 2007 (UTC)
 * I think a centralized discussion at the parent article Natural satellite would be preferable to a lot of dispersed discussions over nine or so different Talk pages. RandomCritic 21:37, 13 October 2007 (UTC)
 * Actually, it was an invitation to join the discussion over there, since it started going somewhere. kwami 21:42, 13 October 2007 (UTC)

"Jovian"
Perhaps somewhere it should be clarified that "Jovian" refers to the same thing. —Preceding unsigned comment added by Greeklamb (talk • contribs) 19:55, 20 October 2007 (UTC)

Earlier name proposals for 6th to 12th satellites
My brother had an "Atlas of the Universe" published in the very early 1970s, which mentions that the moons were mostly unnamed (unique among the planets other than Earth), but that names had been proposed.

The seven proposed names were Adrastea, Demeter, Hades, Hera, Hestia, Pan and Poseidon. I see that Adrastea has been adopted for one of the subsequently-discovered mooons, but not for one of those seven.

I wonder why the astronomical community singled out Jupiter for having unnamed moons. All ten of Saturn's moons had names. All five of Uranus' moons had names. Both of Neptune's and both of Mars' moons were named. Jupiter's only distinction seems to have been that the majority of its moons (7 of 12, then 7 of 13) were discovered during the 20th century and using photography, while it was ensured that the single discoveries at each of Saturn (10th of 10), Uranus (5th of 5) and Neptune (2nd of 2) were named so they didn't stick out like sore thumbs. GBC 07:22, 10 November 2007 (UTC)
 * If I had to guess, it would be that they didn't consider captured chunks of rock to be of the same importance as the larger Galilean moons and moons of the outer planets. We're getting the same argument today, with people saying it's ridiculous to name dozens of 1-mile chunks of rock and call them "moons". kwami 10:15, 10 November 2007 (UTC)


 * See Naming of natural satellites. RandomCritic 14:03, 10 November 2007 (UTC)

Formed in situ what? Formed in situ what?!
In this section there's a sentence that stops abruptly, probably accidently deleted during a prior edit.

Moons of Jupiter

Regular satellites consisting of the Amalthea group of inner moons and the four Galilean moons, formed in situ

Someone should probably fix that. - Norse Am Legend (talk) 00:12, 18 February 2008 (UTC)


 * That sentence is correct. In_situ in this case means that the regular satellites formed in or near their current locations in respect to Jupiter. There's no period on either of the sentences in that short list. --Patteroast (talk) 00:45, 18 February 2008 (UTC)
 * I wiki-linked 'in situ' to try to avoid further confusion. :) --Patteroast (talk) 00:49, 18 February 2008 (UTC)

good job
i like this page —Preceding unsigned comment added by Blackout650 (talk • contribs) 18:46, 12 May 2008 (UTC)