Talk:List of Solar System objects by size/Archive 1

ranking

I'm not sure if I agree with the system of ranking objects that are irregularly shaped. Shouldn't we find the average radius of those objects and use that to rank them? Otherwise, small oblong objects could rank above generally larger but rounder objects. --Patteroast 14:48, 15 Jun 2004 (UTC)

I didn't really use a system when trying to compare and rank irregularly-shaped objects, just more or less did it "by eye". Perhaps there's a better way. -- Curps 17:43, 15 Jun 2004 (UTC)

You could compare for example the average radius - the radius of a sphere that will have the same volume as the moon. If a moon has a volume of V, then the average radius is $3V^{1 \over {3}} \over {4\pi }$Smartech 19:27, 11 July 2005 (UTC)

That's the same as comparing the volumes.

In my corresponding page, I just referred to it as Solar system by size, thereby sidestepping the whole "radius" issue. When one gets down to the irregular bodies, the ranking necessarily becomes somewhat arbitrary anyway. --Doradus 03:09, July 13, 2005 (UTC)

The following post intended for this page was accidentally posted to a broken link by Smartech on 01:21, 12 July 2005. -- BD2412 ^talk 01:45, 4 October 2005 (UTC)

And how exactly should this merging be done? Unfortunately, the two rankings are not the same, since some bodies are denser than others. For example Ganymede is lighter than Mercury, even though the former is the smaller body. In any case, there would be two lists, so in my opinion it is a decision on whether to have those two lists in one article or in two. Smartech 01:21, 12 July 2005 (UTC)

Radius/diameter

Thanks to User:TheTom for catching my goof. I had a suspicion something was wonky but didn't figure it out, even while changing half the numbers. This brings up an interesting question, though. Why are we charting by radius, when the planet infoboxes and most articles use diameters? I'll add a note inside, though, to future editors, so they don't make the same mistake I did! --Dhartung | Talk 18:42, 31 July 2005 (UTC)

Is there an established precedent such that the infoboxes use diameter? Or is choice of diamter versus radius an aesthetic choice that would be preferable to standardize? --Iamunknown 07:40, 17 September 2006 (UTC)

Not sure, the infoboxes almost always go with diameter. Seems to be largely an aesthetic choice: diameter is probably more intuitive because it immediately gives the approximate "size" of the object. Radius is more convenient if you want to run around calculating volumes and surface areas, but that's a marginal pursuit, I believe. Actually, it always mildly annoys me that this list uses radius, so I'm happy for it to be changed to diameter. Deuar 14:37, 18 September 2006 (UTC)

I agree, I would rather see this list use diameters instead of radii. Radii make sense for orbits, but diameters make more sense for planets, stars or other objects. HunterTruth (talk) 16:42, 27 January 2008 (UTC)

Rename

I'd like to rename this article to the following: List of Solar System objects by size. Any objections? --Doradus 21:44, August 3, 2005 (UTC)

Since it's unlikely there would be a different corresponding article, e.. List of Solar System objects by diameter, I don't object. There will be a bunch of redirects to fix, though. --Dhartung | Talk 05:13, 5 August 2005 (UTC)

Keep the "radius" wording, but if you'd like to make a redirect from List of solar system objects by size to this article, go ahead. The problem with "size" is that it's too loosely defined. —Bkell 21:01, 9 August 2005 (UTC)

... or you could go with "volume", if irregularly shaped bodies are causing a problem. —Bkell 21:03, 9 August 2005 (UTC)

The looseness of "size" is why I prefer it. For smaller bodies, there's no easy way to rank them precisely by volume until we go take each body, dip it in a bathtub, and — eureka! — measure how much water it displaces. --Doradus 01:03, August 14, 2005 (UTC)

The looseness of size may make executive decisions for we editors easy, but it makes an unnecessarily confusing, ambiguous, and misleading article for readers. --Iamunknown 07:43, 17 September 2006 (UTC)

Rank is not a useful column

This list is not exhaustive, and so the Rank column is not useful, and may even be misleading. I would like to remove it. Any objections? --Doradus 01:04, August 14, 2005 (UTC)

I sorta like it, but I can't see keeping track past (say) Pluto. I agree it's potentially very misleading for the lower end of the list. Then I can't think of a good argument for only having it for part of the list. Primarily, it's going to be a pain to maintain as more TNOs are discovered and others, like 2003 UB313, have their diameter pinned down. --Dhartung | Talk 01:28, 14 August 2005 (UTC)

I'm not sure why the Rank column is 'not useful'... this is a list of objects by size, correct? Going from largest to smallest? In which case, the size-ranking is of interest. --Firsfron 03:46, 27 August 2005 (UTC)

As I said, it's not useful because the list is not exhaustive. The rank we present is meaningless, aside from listing where an item appears in our list. There's absolutely no reason to believe, for instance, that Mercury is the 11th-largest body in the solar system, since we could discover a larger TNO at any time. This problem becomes even more pronounced as one moves downward in the list, at which point there are even known bodies that are not in our list. I have started by removing the ranks after Europa, since the relative ordering of Triton and UB313 are not known. --Doradus 16:27, August 27, 2005 (UTC)

According to Dave Jewitt, we could discover something larger than Jupiter at any time, too: "a planet of Earth's mass could exist undetected if it were more than a few 100 AU away, and even a Jupiter (300 Earth mass planet) could exist at distances only slightly greater." (from the Kuiper Belt Page: http://www.ifa.hawaii.edu/faculty/jewitt/kb.html ) However, there is ample evidence that Jupiter is the 2nd largest body in the solar system, and that Mercury is the 11th-largest body in the solar system: in over three hundred years of telescopic astronomy, we haven't discovered anything larger.

Does the possibility of something existing that is larger than Jupiter mean Wikipedians can never create a list including the rankings of known objects by size, because there might be something larger? Of course not. Many resources, including books and web-sites, refer to the size-ranking of various bodies: check here for Mercury , here for Jupiter, and here for Europa (official NASA site, BTW). If NASA's ranking planetary bodies by size, there's no reason Wikipedia can't. --Firsfron 22:27, 27 August 2005 (UTC)

The potential to find new objects is secondary; I'm sorry I focused on it in my remarks, because it was a spurious argument that seems to have utterly distracted you from my main point, which is that our list is not exhaustive. Even if it could be made exhaustive, which I doubt; even if we could find some means to include every known solar system object in the list, and keep it up to date with new findings; the sizes of most of them will never be known with enough precision to allow them to be ranked. The whole concept of the ranking is fundamentally futile beyond about 15th or so.

Having said all that, if you would like to use a ranking you find in another source, and cite it, be my guest. Wikipedia is all about collecting knowledge from credible sources. --Doradus 03:26, August 28, 2005 (UTC)

Hmmm. Yes. I believe you said that, once or twice. "You keep using that word. I do not think it means what you think it means." ;) Exhaustive: from Dictionary.com : very thorough; exhaustively complete. I'm not exactly sure how you think this list of objects could be more thorough or complete. If you think the list is incomplete, I wonder why you don't add the information you have (with suitable citation, of course). If it's just that you believe that more objects exist out there, yet undiscovered, I think I already addressed that: there's always the potential for larger objects (than Mercury or Jupiter) to exist, but we haven't found any, in the last three hundred years. And even if we do, it's really not too hard to update the list. Meanwhile, these are the largest objects known to exist, outside of fringe speculation and conjecture. If you're basing your objection to rank based on speculation, I don't know what to tell you: I've taken a look at your edits on other pages, and they seemed really sound, so your argument here seems quite puzzling.--Firsfron 13:05, 28 August 2005 (UTC)

Please, just for one moment, consider the possibility that I'm not an idiot. Maybe, just maybe, I have a point, and that is this: 1) there are upwards of 5000 bodies currently known in the solar system; 2) most of them are very small and their sizes are only known to one significant figure, and 3) this makes a ranking of 90% of the bodies impossible and meaningless. --Doradus 16:09, August 28, 2005 (UTC)

I don't think you're an idiot, Doradus. In fact, I thought I pretty much said that above, when I said I liked your earlier articles. I'm not sure why you thought I didn't think you weren't intelligent, as my post tried to indicate something else entirely.

I'd like to address these new points, P3, but I wish you would have mentioned them earlier. Anyway, back to your new points, which weren't mentioned earlier.

And I wish you had asked, or found out for yourself, rather than assume I was mistaken. ;-)

1) there are upwards of 5000 bodies currently known in the solar system; 2) most of them are very small and their sizes are only known to one significant figure, and 3) this makes a ranking of 90% of the bodies impossible and meaningless.

There are certainly 5000 bodies currently known in the solar system. Most of them are very small and their sizes are not all certain, true. However, you're off on point three: the list we are discussing doesn't contain 5,000 bodies. It contains the largest bodies known. You say this makes a ranking of 90% of the bodies impossible and meaningless, but in point of fact, the 90% of the bodies were never on this list. Only the largest bodies were on this list, and their ranking according what's currently known. Astronomy is an ever-evolving field, and our knowledge of heavenly bodies is always expanding; that doesn't mean that a list of solar system bodies, or even a ranking of known solar system bodies, is meaningless: as I said earlier, more than one resource, even NASA sites, cite size ranking, so obviously it's important to some people. Certainly the high school student who is writing a report on Saturn might find it useful to mention that Saturn is the third-largest body (known) in our solar system, and that's where a ranking might be useful, and not at all meaningless. Cheers! --Firsfron 16:42, 28 August 2005 (UTC)

First, the 35 or so bodies we have listed are not the 35 largest known bodies. They are the 35 bodies that people felt like adding to the list. That is why I keep saying the list is not exhaustive (though that could be fixed). Second, out of just these 35 bodies, the rankings of more than half of them are uncertain. Thus, even if you don't want to consider all 5000+ bodies, my points still stand with just these 35. Our rankings for most of them are meaningless. --Doradus 21:44, August 29, 2005 (UTC)

First, the 35 or so bodies we have listed are not the 35 largest known bodies. Not true. According to [[1]] the KBO on our list are the largest objects. Also compare with [2]. Neither site lists any KBOs that are larger than any on our list, so this isn't a case of the list here being inaccurate because people 'felt like adding bodies to the list'. As far as I can tell, Wikipedia's list here agrees with the findings on both of these sites, which I might add are run by professional astronomers. See also my talk page or yours for further comments. --Firsfron 04:37, 30 August 2005 (UTC)

I concur with the elimination of a ranking number past 15, and I've added an editorial note to that effect inside the article (with a see talk). I think it's OK to have it there, at least partially, because it's something that a casual reader might expect.

Regarding Jupiter: It's certainly possible for a Jupiter-sized object to exist on a very long orbit of the Sun, if hypotheses about a brown dwarf companion have any validity. --Dhartung | Talk 05:06, 28 August 2005 (UTC)

Hypotheses about brown dwarf companions to the sun are always interesting, of course, but doesn't that sort of fall into the category of speculation? --Firsfron 13:10, 28 August 2005 (UTC)

I was just responding to the over-certainty in the earlier comment. In fact, I think it's more certain that we will discover planetary bodies at least as large as Europa -- in other words, our Top 15 is by no means finished -- and remains possible that we will discover very distant gas giants at least as large as Neptune, so that the Top 5 might even change one day. That doesn't change my view that down past 1500km there are going to be objects too numerous (er, hyperbole) to count, let alone definitively rank. In fact, I think these are complementary views. --Dhartung | Talk 23:49, 28 August 2005 (UTC)

That doesn't change my view that down past 1500km there are going to be objects too numerous (er, hyperbole) to count, let alone definitively rank. While I agree there are still many bodies left to be discovered, some of which could be quite large, if the Main Asteroid Belt is any example, most of the larger objects in the Kuiper Belt have already been discovered (the first four asteroids discovered represent a majority of the mass of the entire main belt). In the past twelve years, we've discovered less than a dozen objects in the 1000 km range, which works out to less than one per year. That average doesn't really support claims of many large ("too numerous to count") objects in the range of 1500 km, and even if we discovered a large object every year for the next hundred years, we'd only have to update the list once a year.--Firsfron 18:30, 29 August 2005 (UTC)

David Jewitt, who discovered the first TNO, beleives that the Kuiper Belt contains some 70,000 objects larger than 100km, and is 300 times more massive in aggregate than the asteroid belt. [3] There are only 230 asteroids that large; and we're not necessarily counting objects in the Oort cloud (of which one is on our list already). Most of these are icy and dark. I don't think the history of asteroid belt astronomy is necessarily an excellent match; the first several TNos aren't even on our list, and it was only 1998 when we discovered the first of them (Ixion) and that's now the smallest listworthy object. So I still think there are a lot of them out there, and I don't think that 2003 UB313 is the upper bound; the odds are simply against it. Anyway, my argument has little to do with updating the list regularly; if anything, Wikipedia is in a better position to keep an updating ranking than NASA or anybody, because they publish static pages, while ours might be updated within minutes of an announcement. I'm just concerned that the ranking ceases to be useful after a certain point, because we simply don't know the mean radius value on which it is based to a reliable degree of accuracy. --Dhartung | Talk 19:54, 29 August 2005 (UTC)

the first several TNos aren't even on our list, and it was only 1998 when we discovered the first of them (Ixion) Actually, of course Pluto and Charon are TNOs that are on our list, so of course Ixion wasn't truly the first. I do certainly agree with you that the Main Belt discoveries may not be, as you say, an 'excellent match', however even with the great probability of thousands of objects in the 100 km range, the rate of discovery of larger, 1000-km-scale, objects (less than one per year during the past twelve years) doesn't really support the idea of vast numbers of 1000km+ objects. I certainly also agree with you that the ranking ceases to be useful after a certain point, but strongly disagree at where that point has, IMHO, arbitrarily been placed. There were less than 40 rankings on the list, and the majority were removed because the rankings 'were not useful' or something, based on the perception that the list was not accurate at its lower end. {Doradus -- I removed rankings after after Europa because the relative ordering of Triton and UB313 are not known.} There are, however, no other bodies that belong in amongst these ones, according to [4], which is updated as new large discoveries are made. I also agree that Wikipedia has a better chance of remaining up-to-date than NASA's site or other places. --Firsfron 05:03, 30 August 2005 (UTC)

I'm glad we agree on some things! (And yes, I do fall into the Pluto=TNO camp.) Putting it quite simply, speaking only of the known bodies, after #15 is where we start to get bodies whose mean radius is not known with any certainty. 2003 UB313 could be 16th through 19th, depending; Orcus could be 19th through 36th, by my count. Given that, assigning ranks is purely arbitrary. Cheers. --Dhartung | Talk 06:27, 31 August 2005 (UTC)

To rank or not to rank

The previous discussions have become quite voluminous, so let's see where we stand.

Can we agree on these two points?

• The list currently does not contain all known solar system bodies. It does not even contain all known bodies in the size range it covers. This could be fixed if we wanted to do so.

• The size of most solar system bodies is known only approximately. Therefore, rankings beyond a certain point are meaningless. (Note: I have currently pegged this at number 15, because we currently don't know whether Triton is larger or smaller than 2003 UB313.) This point will increase over time, but the large majority of known solar system bodies will always be unrankable.

In light of the new statement on 2003 UB313's diameter in the 2/2 Nature by Bertoldi et al., I have (1) changed the radius to reflect the latest figures, (2) placed 2003 UB313 higher than Triton on the list, (3) removed the "15" ranking from Europa (since it is possible that 2003 UB313 is larger than Europa). RandomCritic 14:30, 1 February 2006 (UTC)

I see a few possible courses of action. Please add more to the end of the list if I have forgotten any.

1. Remove the Rank column. (This was my original proposal.)
2. Include ranks only for those bodies unaffected by known omissions and ranking uncertainty. Leave the Rank column blank for all other bodies. (This is the list's current state.)
3. Include only bodies unaffected by known omissions and ranking uncertainty. Include ranks for all bodies in the list.
4. Include rankings for all bodies in the list, despite ranking undertanty. Fix known omissions by adding the missing bodies.
5. Include rankings for all bodies in the list, despite known omissions and ranking uncertainty. (This was the state of the original Rank column.)

It's only #4 and #5 that I really object to. #3 seems to exclude a large number of interesting bodies (like Pluto).

My original proposal was #1, but having read other people's arguments, I think I'd now prefer #2. --Doradus 18:20, August 31, 2005 (UTC)

If we're voting, then Option 2 is my preference. I think it's a reasonable compromise between readers' expectations of some sort of ranking in a list "by N", and the known unknowns. --Dhartung | Talk 07:04, 1 September 2005 (UTC)

I'm fairly happy with Option 2, if we're putting it to a vote. 1-16 have all been visited by probes and their sizes are well-known (since the 1980's, in fact), so there's little controversy on their respective sizes and rank in size. Having said that, the current Wikipedia article on 2003 UB313 lists its radius as anywhere up to 2,500km. --Firsfron 16:31, 1 September 2005 (UTC)

I'm neutral, but while we're talking about the rank coloumn, did anyone notice that the images are overlapping the numbers? :| 66.134.206.66 20:11, 4 February 2006 (UTC)

Wrong radii?

Okay, these radius figures are all wrong. For example, it list Pluto's diameter as being 1195, when it's really 1430. That's just one example, as they all seem to be wrong. What's up with that?

What do you mean? I see Pluto's radius in the table as 1153 not 1195. This is directly from the Pluto article. Note also that it's the radius not the diameter that's tabulated, and in any case a diameter or radius of 1430 for Pluto is way out. Do you have any other examples? Deuar 10:55, 30 April 2006 (UTC)

(1153x2)x1.6 = c. 1430 (1433 might be more accurate). Get it?

Rich Farmbrough 23:16 10 May 2006 (UTC).

Well, I understand that 2×3=5, but i'm getting a bit lost with these bigger numbers! Deuar 10:47, 11 May 2006 (UTC)

Name change

I moved this article from Geological features of the solar system, keeping in line with the lower-case usage at solar system. Please see Talk:Solar_system/Archive_001#Solar_System_vs_Solar_system and Talk:Solar_system/Archive_001#Requested_move (with discussion) for rationale. — Knowledge Seeker দ 22:10, 14 May 2006 (UTC)

Recommend change

In the chart, the earth's moon is called "moon". Is not the name for earth's moon suppose to be "Luna"? —Preceding unsigned comment added by 64.31.11.2 (talk • contribs)

See Moon. In English, Luna is basically a romantic or fanciful name. The Earth's moon is generally called the Moon. --Dhartung | Talk 23:14, 17 June 2006 (UTC)

Actually I'm pretty sure that Earth's moon is called The Moon (note the capitalization) just as the star we revolve around is called The Sun. I know I read that on wikipedia, but I can't source it so I won't make changes. Prnd3825 22:18, 27 February 2007 (UTC)

It's only capital-T "The" at the start of a sentence. Mid-sentence, you would use "the Moon". Same goes for the Sun. --Ckatz^chat_spy 22:21, 27 February 2007 (UTC)

I'm quite sure that our moon's scientific name is Luna, to distinguish between it and other moons orbiting different planets. Mrug² 19:55, 28 February 2007 (UTC)

Check this out: NASA explanation

"The Moon was called Selene or Artemis by the Greeks and Luna by the Romans. I'm sure other cultures also had names for the Moon. But in English, Moon (from Mona and Moone in Old and Middle English) was used before anyone had any idea that the other planets had moons. So it was more a case that the specific name for the Moon was extended to mean small bodies revolving around planets elsewhere. The Moon's name is the Moon."

--Ckatz^chat_spy 20:12, 28 February 2007 (UTC)

Mrug2, I've been in amateur astronomy circles since the 1970s and I've never once heard anyone call it "Luna". If you believe this name change is warranted, this topic should be continued at Talk:Moon. --Dhartung | Talk 00:16, 1 March 2007 (UTC)

Why radius?

Why we use radius, not diameter?--Nixer 09:17, 15 July 2006 (UTC)

Why use the diameter? Why not use radius? --Iamunknown 07:39, 17 September 2006 (UTC)

ranking

With the smaller uncertainty in 2003 UB313, it looks like Triton can be confidently ranked 16th largest of the known bodies. Deuar 15:04, 24 August 2006 (UTC)

Thumbnails to wide?

Is it just my system, or a common view? Looking at the list, the thumbnails of the planets (etc) overlap onto the list od radii, partially obscuring the first digit.86.16.42.154 00:00, 25 August 2006 (UTC)Darkson

You were the second complaint. It turns out that the center syntax in the image tag for that column was causing an overlap in Internet Explorer, a bug not visible in Firefox. When I removed it there seemed to be no ill effects at different browser sizes in either software, so I hope that fixes it for everyone.--Dhartung | Talk 02:50, 25 August 2006 (UTC)

Eris and Pluto

It's odd that Pluto is listed by its numbered designation while Eris is listed as simply Eris. This is presently the reverse of the titles of their respective Wikipedia articles. Considering the heightened state of awareness over these two names, I recommend either using the same format for both names, or following the naming of the main articles for these two dwarf planets. There has been enough debate over this already to justify such a change. 69.136.238.165 23:05, 14 September 2006 (UTC)

Both those articles have been subject to page-move wars, so that's not really an arbiter. Right now there's a requested move discussion taking place on Talk:136199 Eris#Requested move.--Dhartung | Talk 01:57, 15 September 2006 (UTC)

I suggest removing the numbers from all minor planets to make their names more readable. --Greg K Nicholson 05:19, 16 September 2006 (UTC)

I took the liberty of removing the '1' from the name of Ceres -- to be consistent both with the naming of other dwarf planets, and with the name on Ceres' own page which has already been thoroughly discussed over there. Anyway it's nearly impossible that anyone would think the name refers to the goddess in the context of this list. Montalto 18:05, 6 November 2006 (UTC)

Merge proposal

Proposal to merge content from List of planetary bodies into this article: 1. Because the objects treated are effectively the same. 2. Because the basis for determining a "planetary body" is not sufficiently different from the criteria for inclusion in this list to potentially result in a different set of inclusions, and therefore the two articles will be near-duplicates. RandomCritic 21:44, 3 November 2006 (UTC)

I disagree, basically because I think there's an added value in having a list that's ordered.Junuxx 16:04, 5 November 2006 (UTC)

I think I disagree as well. I think the other article should not be a list by size but an alphabetical list by type. --Dhartung | Talk 18:33, 5 November 2006 (UTC)

I also disagree and will rework the list and change the order of the objects.--Planemo 18:53, 5 November 2006 (UTC)

Disagree as well − both orderings are valuable. Deuar 18:15, 9 November 2006 (UTC)

Images

Should we be using only true images of these objects (be they true or false color), or is it acceptable to mix in some conceptual art images of what they might look like? (i.e. FY9 and EL61)~~Sethhater123

There was a discussion of this same issue a while back at Talk:List_of_solar_system_objects_by_mass#Should we have artist's impressions?. I would say artists impressions are ok provided there is absolutely no real image available and that they are easily distinguishable. What was done over at the list by mass was to give them a different-colored background. (Although they actually seem to have disappeared again now. Can't remember when) Deuar 19:52, 30 March 2007 (UTC)

Common number format

Why does the Mean Radius vs Earth and Volume vs Earth start at using decimals then switch to percentages. It should probably be consistent throughout the column

Yes they should initially when it was created it was assembled in a mish-mash fashion. Abyssoft 15:20, 12 April 2007 (UTC)

No, it was not mish-mash. It was considered easiest to understand. If they are all fractions, then Ceres becomes 0.076 instead of 7.6%. If they are all percentages, then the Sun becomes 10925%. --Doradus 13:56, 11 June 2007 (UTC)

Something seem wrong with the lists...?

I'm not sure... could someone take a look?

If you press that button at "Mean Radius" twice, the order is different from where it was in the beginning. I think it's because of using both decimals and percentages. Also, using mean radius, Earth is at the top of the list, where the Sun should be. I think this is because of the space between numbers in 696 000. 74.116.137.2 21:22, 21 May 2007 (UTC)

Fair use rationale for Image:Xenaandgabrielle.jpg

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Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Wikipedia:Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images lacking such an explanation can be deleted one week after being tagged, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.

BetacommandBot (talk) 08:01, 15 January 2008 (UTC)

Mass fraction of system

While the graphics (esp. "Relative masses of the bodies of the Solar System" pie charts) are nice, some people (read: I) wouldn't mind seeing a column (at least for objects >400 km) showing the percentage of the whole 1.0014 M_sol mass of the solar system. Any possibility?

49.183.87.182 (talk) 04:09, 2 October 2016 (UTC)

External links modified

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Sorting by Mass

I notice that when we sort the list by mass the exponent is ignored. Is there anything we can do about this? It makes it difficult to compare a 2.1×10²⁰ kg body to a 8.8×10¹⁹ body. -- Kheider (talk) 19:36, 5 December 2008 (UTC)

I'm not sure, but it might work if we use the exponent template {{e|20}} or {{e|19}} instead of spelling it out. Serendi^podous 19:40, 5 December 2008 (UTC)

I don't think the sort program is that smart so I am filling the M_Earth column for the known masses so that the list can be sorted by mass. I am currently leaving out the assumed^A masses since they are just guesses. -- Kheider (talk) 18:44, 6 December 2008 (UTC)

Mass list added

The entire mass list is now incorporated into the big list. Now I want to go over the list and condense it (there's no point in having two different measurements of the same value (km or kg vs Earth) in separate columns), add Surface gravity, type of object and sphericity. Serendi^podous 18:04, 6 December 2008 (UTC)

I think we should keep both of the Mass columns. One for common use (kg) and one for wiki-sorting (M_Earth). If you currently sort the Mass kg column you will see that Ceres is the most massive at 9.5. :-) -- Kheider (talk) 19:29, 6 December 2008 (UTC)

I've made a request on the Lists talk page. I hope we can figure out how to do it. If worst comes to worst we can change kilograms for yottagrams (×10²¹ kg). Serendi^podous 20:00, 6 December 2008 (UTC)

Ouch. I notice NONE of the columns are sorting properly. -- Kheider (talk) 11:18, 7 December 2008 (UTC)

Yeah, I noticed that too; I reverted everything. Shame. If I want this merge to work, then this list is going to have to be really wide. Serendi^podous 11:21, 7 December 2008 (UTC)

This merge is still a good idea because a sortable list is better and all the data could be kept in one list. Besides when I think of masses I think in kg, not yg. If we wanted to we would keep the assumed^A asteroids from cluttering the "sorting by mass" by not inserting a M_Earth value for them. I realize that for objects beyond Saturn, including most of the smaller moons of Uranus and Neptune, "assumed masses" is the only way we can really do a complete list.-- Kheider (talk) 11:46, 7 December 2008 (UTC)

Red Links

Should we remove the red TNO links? Their radii (200-264) appear to be taken from Johnston. With an article like this I prefer TNOs with a better estimated size, ie "Johnston #" and the Spitzer list. -- Kheider (talk) 17:59, 8 December 2008 (UTC)

I'm sure Johnston used a source to cite it. And he lists his sources on his page. We could always create their pages. Serendi^podous 19:32, 8 December 2008 (UTC)

Yes and no. On Jonhston's page, objects marked with a # next to the diameter have actually been professionally estimated. All other bodies are "assumed to have an albedo of 0.09". I looked at the red link TNOs, they are all assumed albedo 0.09 (per Johnston). I don't mind assumed albedos for the largest bodies, but these red links are basically small unknown TNOs. -- Kheider (talk)

I've had a think and I have decided that I agree. They should go. The only one I think we should keep is the last NEA, since I'm sure that one's radius can be determined fairly accurately.Serendi^podous 11:51, 9 December 2008 (UTC)

Given their large radii and potential as dwarf planets, I added 2005 UQ513* 462, 2007 UK126* 439, 2003 UZ413* 303 (all assumed albedo 0.09) to the list. -- Kheider (talk) 18:09, 9 December 2008 (UTC)

If Chiron is on this list, then shouldn't Charilko, which is bigger than Chiron, also be on this list? Serendi^podous 20:24, 9 December 2008 (UTC)

Yes we need to list the largest centaurs, just as we need to list the largest dwarf planet candidates. With that in mind I also believe that we should list 1995 SN55 that could turn out to be the largest known centaur. -- Kheider (talk) 17:25, 10 December 2008 (UTC)

Radius

Currently * symbolizes "Radius is known only very approximately". We need more tags for radius. Should ^R be used for "Objects that have been determined by various methods, such as optical (Hubble), thermal (Spitzer), direct imaging via spacecraft." This would be good for say Eris, Haumea, 2002 TC302, Orcus, MS4, AW197, GV9, AZ84, UX25, TL66, DE9, Huya. We could also have a ⁹ label for all the basically unknown "assumed albedo 0.09" objects. The * will also be good smaller moons like Sycorax.

This would give us:
* Radius is known only very approximately
^R Radius has been determined by various methods, such as optical (Hubble), thermal (Spitzer), or direct imaging via spacecraft
⁹ Unknown radius, generic assumed albedo of 0.09
-- Kheider (talk) 23:34, 10 December 2008 (UTC)

At some point we're going to have to go a lot farther than that. We are going to have to provide an individual reference for every established radius and note any radius that is derived from other properties, such as albedo. I know it will be tedious, but that's how these things work. Serendi^podous 10:22, 11 December 2008 (UTC)

I think this merge may be a lost cause

The sortbot simply can't handle so many terms. It can sort the mass figures alright going up, but not down, even when all the figures are regularised. Serendi^podous 12:32, 11 December 2008 (UTC)

Maybe we should split the list in half, one for bodies above 100km in radius, one for bodies below 100 km in radius. Serendi^podous 12:36, 11 December 2008 (UTC)

Heck, I'll just try it. Serendi^podous 14:52, 11 December 2008 (UTC)

I did it and it worked! Yay! One thing; while I was sorting out the over 100s from the under 100s, I noticed that 283 Emma's radius seemed remarkably big for something of its mass. Are you sure it wasn't 48, rather than 148? Serendi^podous 15:23, 11 December 2008 (UTC)

Looks good. Yes, 283 Emma (Binary) has a density of 0.83 per BAER. BAER is the source for current volumes and masses of the asteroids. This is why I tagged it with a (M)ass known. This is also part of the reason I like keeping the M_Earth for objects with known masses. Otherwise you don't know when you have a 8 Flora (Density 7+) or an Emma. -- Kheider (talk) 15:39, 11 December 2008 (UTC)

Baer

I figured Baer (as a source) would be coming up. Baer just gave a presentation at the AAS Division of Planetary Sciences meeting in October. This is why I have been busy playing with the masses of the asteroids so much. Baer also put out a paper in 2007.  :-) -- Kheider (talk) 15:50, 11 December 2008 (UTC)

I just realised a second problem

Now that the tables are split, many objects in the lower table actually higher masses and surface gravities than those in the upper table. I wonder if the merge is worth this or whether we're better off with the three old tables. Serendi^podous 17:28, 11 December 2008 (UTC)

• One master table to maintain is better than 3 "very generic" tables. And for the most part it appears sortable.
• I still doubt the gravity entries for the smaller objects with assumed diameters and masses (Below Miranda @ surface gravity.) Those with known masses are (assumed) ok.
• Since the start of this project I figured this master table may get split into two sections, kind of like planet vs dwarf planet. :-) There will always be little rocks with more mass than a chunk of styrofoam.
• I am still comparing various sources for the diameters of the smaller moons: JPLSSD, Sheppard, NSSDC. Things get pretty wild around Sycorax (diameter 150-190).
  -- Kheider (talk) 18:29, 11 December 2008 (UTC)

Mass and radius are now in

All that remains is surface gravity. Since there are about 100 entries to input (starting at Elara) I would very much appreciate it if someone else could help in shouldering the load. Serendi^podous 16:05, 11 December 2008 (UTC)

• According to surface gravity, Sycocrax has a radius of 75km (Sheppard/NSSDC), but it claims it has a mass of 5.4×10¹⁸! Ouch, that would require it to have a density of 3. I think Sycorax probably has a density of 1.3 to 2. But if the original entry showed a radius of 95km (JPLSSD) with a density of 1.5 then we would get a mass of 5.38×10¹⁸. Crud, even the original entry shows a radius of 75. :( -- Kheider (talk) 19:29, 11 December 2008 (UTC)
• For Caliban, a radius of 36km and mass of 7.4×10¹⁷ requires a density of 3.8. Ah, I see. They took their mass estimates straight from the (April 2007) wiki articles, and if those numbers were a mix match of different edits to the mass, radius, etc... you get weirdness. -- Kheider (talk) 23:03, 11 December 2008 (UTC)

Bugger. Since it would appear that adding any more figures from that list would be more dangerous than not doing so, I'll just go ahead with the merge. I guess I'll have to do what I usually do: drag Ruslik over here to do the calculations. Serendi^podous 19:47, 11 December 2008 (UTC)

I have been starting to compare the mass and gravity figures to what are given in the main articles and most of them do not deviate too much. But yes, I think I trust the main articles to be more up to date. And we really only want 3 sig figs for smaller bodies. If Ruslik works on it, I would have him start with bodies that have a known mass/radius (JPLSSD) instead of the assumed densities. -- Kheider (talk) 20:31, 11 December 2008 (UTC)

List of named Solar System objects

This list contains a number of objects that we might want to include in the bottom list. Serendi^podous 12:26, 13 December 2008 (UTC)

Maybe. But I am trying to stay away from adding too many poorly known objects (with radii<20 km) that have assumed masses. I have even given some thought to removing asteroids 141 Lumen through 100 Hekate since they are little known asteroids with assumed masses. We have enough quality asteroids with known masses for the list, IMO. -- Kheider (talk) 18:51, 14 December 2008 (UTC)

The list no longer exists.--Roentgenium111 (talk) 00:16, 16 January 2010 (UTC)

Kheider

could you link to your sources? Lists need to have some form of referencing, even if it's not as rigorous as the referencing for an article. Just posting them at the bottom should be enough. Serendi^podous 22:56, 15 December 2008 (UTC)

Problem of Mass Unit?

It appears to me that masses given are in Kg x 10 to the 24th but unit shown in heading is Gm x 10 to the 24th(Yg).Dspacenut (talk) 17:26, 18 February 2009 (UTC)

The top list gives its values in 10^21 kg (Yg). The bottom two lists give mass values in 10^18 g (Eg). Serendi^podous 22:50, 18 February 2009 (UTC)

Volume in Earths

My calculations are giving completely different values to the numbers listed. Can someone check please? Serendi^podous 21:38, 3 March 2009 (UTC)

Having a quick look at Mercury, Venus, Jupiter and Neptune using http://nssdc.gsfc.nasa.gov/planetary/planetfact.html I don't see a problem. Which objects did you see a problem? -- Kheider (talk) 22:50, 3 March 2009 (UTC)

Could you have a look at Charon and Umbriel? Serendi^podous 07:36, 4 March 2009 (UTC)

Umbriel: Volume of a sphere with radius 584.7 km = 837,313,109.4 km³ / 1,083,207,317,374 km³ = 7.7E-04 = 0.00077 Earth
Charon: Volume of a sphere with radius 603.5 km = 902,704,853.6 km³ / 1,083,207,317,374 km³ = 8.4E-04 = 0.00084 Earth
-- Kheider (talk) 14:22, 4 March 2009 (UTC)

Right. So they're wrong on the page. The list claims the volumes are 0.095 and 0.092 x10^9 km^3.

Which is not only the wrong value but appears to be off by a factor of ten. For me, 837,313,109/10^9 is 0.837, not 0.0837.

Which means I have to manually go through the entire list and redo the whole thing.

Bugger. Serendi^podous 14:41, 4 March 2009 (UTC)

This list claims that Charon has a volume of 0.87*10^9 = 870,000,000. Though it should be closer to 0.9*10^9, I do not see where it is off by a factor of ten. It also depending on how the original author rounded and what estimated radius they used. Heck even the Charon article claims radius 603.5 ± 1.5km while Planetary Satellite Physical Parameters shows 603.6 ± 1.4. The radius of Charon to Earth is 604/6378=0.0947 (which is what this article shows.) -- Kheider (talk) 15:37, 4 March 2009 (UTC)

OK, I've been reading the wrong columns. God this is painful. But still, it means that OR10's volume is going to be misplaced when it's added, unless I redo all of the volume figures. Serendi^podous 18:14, 4 March 2009 (UTC)

Are the "Mean Radius" and "Volume" columns supposed to be related by the formula V=4/3*pi*R^3 ? Currently they aren't because Eris's R is greater than Pluto's, and Pluto's V is greater than Eris's. —Preceding unsigned comment added by 92.225.99.73 (talk) 11:17, 24 August 2009 (UTC)

Ceres

MPEC 2006-R19 : EDITORIAL NOTICE says:

• "Ceres, Pluto and 2003 UB313 were identified as members of this new category"
• "It should be noted that, just as some of the numbered objects that have exhibited cometary activity also have designations in the catalogue of numbered periodic comets, the numbering of "dwarf planets" does not preclude their having dual designations in possible separate catalogues of such bodies."

IAU Questions and Answers on Planets says:

• "Ceres is (or now we can say it was) the largest asteroid" (clear as mud. So what was the first asteroid discovered? 2 Pallas?)
  

-- Kheider (talk) 12:00, 8 March 2009 (UTC)

Kheider, thanks for adding the "in the asteroid belt" part. I actually intended to do something along those lines, but forgot for some bizarre reason. (The "DP in the asteroid belt" format is consistent with what we are doing in other articles involving Ceres; keeping the "asteroid" status somewhat ambiguous in the absence of any definitive statement.) It also with how we don't identify Ceres as the xth planet discovered; identify it as a DP and leve the rest as background. --Ckatz^chat_spy 19:26, 8 March 2009 (UTC)

Surface gravity

It can be argued that we don't need surface gravity measurements for those objects under 20 km, but why leave the field there while removing the title? That makes no sense. Serendi^podous 12:16, 8 March 2009 (UTC)

Because the small objects aren't in gravitational equilibrium (i.e., they are potatoes), the surface gravity will vary depending upon where on the surface you are doing the measuring. The value computed from the mass and mean radius is really just a theoretical upper bound. This applies to the 20-200 km objects, too. For example, one of those dog-bone asteroids will not have anywhere with a surface gravity near the value computed from the mass and mean radius. So I think surface gravity should be dropped from the under 20, and probably from the 20-200, too, since it isn't any actual surface gravity on the object. Tbayboy (talk) 15:47, 8 March 2009 (UTC)

Very well. But the problem is that many of the mass calculations for the smaller objects were obtained by assuming sphericity and then a likely density. I would prefer a cited mass figure if one can be found, but that isn't always possible. Serendi^podous 11:42, 9 March 2009 (UTC)

density?

i was thinking of adding density to the tables, as this is also an interesting attribute. Then people could sort a list, showing for example that the average density of Earth is higher than the Sun.

I thought i would ask before doing so, is there a reason that density is not included? Is it because mass and volume are provided?

I think density is important enough to be included. Sorting by density would be a lot different that sorting by either mass or volume, it paints a whole different picture. —Preceding unsigned comment added by 203.219.216.45 (talk) 15:17, 22 April 2010 (UTC)

Good point. Will get onto it eventually. Serendi^podous 20:12, 24 April 2010 (UTC)

When sorting by density (descending) on the first panel Pluto comes out on Top , over Earth 5.514 g/cm^3 and Mercury 5.427 Obviously at 1.87± 0.02 g/cm^3 it should be on position 12 after Titan . It is my impression hat Pluto is there alone in a category by itself and thus appears on top. Can someone try to correct this. I would myself but I am afaraid I might mess things up. Thanks Rudy235 (talk) 02:16, 1 October 2015 (UTC). I went ahead and corrected that glitch on the ability to sort by density.. I hope it did not spoil anything that should have remained.Rudy235 (talk) 02:31, 1 October 2015 (UTC)

It looks like a bug in Template:Val (which I've reported). Values using Val do not sort properly with values not using it. Ideally, all values should be listed using Val. --JorisvS (talk) 11:46, 2 October 2015 (UTC)

repetition

-- object 140 Siwa is repeated; around 55 km radius. ........ Well spotted. Serendi^podous 20:12, 24 April 2010 (UTC)

Trojan 4348 Poulydamas albedo

A Jupiter Trojan discovered in 1988 that's over 100km in diameter? Forgive me if I'm doubtful. — kwami (talk) 01:26, 31 May 2010 (UTC)

Just curious because of the "1988", but what exactly makes you doubtful? Anyway, looking at the IRAS source documents, the diameter is calculated from the absolute magnitude using an assumed albedo of .01, whereas other entries in the Wikipedia table with unknown albedos use the standard .09. Note that using that assumed .01 albedo, the source also lists 9 Metis as 737 km, Irene as 730, Euterpe as 529, etc. With .09, Poulydamas would have a diameter of 64 km. Tbayboy (talk) 23:28, 31 May 2010 (UTC)

It's the same size and distance as 624 Hektor, but took another 80 years to find? That just set my BS detector off. And, as you note, the albedo assumption applied to Metis and Irene make them the protoplanets rather than Vesta and Pallas. Of course, maybe Poulydamas is unusually dark and so just escaped notice, but our article on it mentions nothing about it being tied with Hektor as the largest known Trojan. — kwami (talk) 00:21, 1 June 2010 (UTC)

With absolute magnitude H=9.2, 4348 Poulydamas generically (one size fits most) should have a diameter of around ~60km. Assuming a generic trojan albedo of 0.06 would yield a size of ~80km. An albedo of 0.02 (624 Hektor has an albedo of 0.025) would still only place Poulydamas at 135km. In 2004 the European Asteroidal Occultation Network listed it pre-occultation as 48km in diameter. Trojan 2456 Palamedes H=9.6 has an albedo of 0.03 giving it a size of 91km. Asteroid 1049 Gotho is H=12 with a very dark albedo of 0.01 (size=51km), but he is a rare breed. -- Kheider (talk) 00:54, 1 June 2010 (UTC)

Since you've bumped the size down to 24km, below the 100-km limit of the table, shouldn't it just be deleted, and the info moved to the Poulydamas article? — kwami (talk) 09:04, 1 June 2010 (UTC)

I moved it down. Serendi^podous 09:11, 1 June 2010 (UTC)

Distance from Sun column

I think we should add a distance from Sun column that would make it easier to find bodies so that the object can be sorted to follow the more common pattern of Sun, Mercury, Venus, Earth, Moon, Mars, etc. --TimeHorse (talk) 15:42, 15 June 2010 (UTC)

Ultimately, the plan is, once (if) this article ever gets to FL then to go onto List of Solar System objects and do a complete workup of their orbital elements, from semi-major axis to eccentricity to argument of perihelion. Serendi^podous 16:38, 15 June 2010 (UTC)

A distance from the Sun column is a great idea. Does anyone have a link to the information? I am glad to work on it.--Wyn.junior (talk) 17:52, 5 February 2019 (UTC)

File:2003 EL61.jpg Nominated for speedy Deletion

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Using non-free images in the list

The images of 2867 Šteins (File:Steins-Rosetta.jpg) and 25143 Itokawa (File:Itokawa4.jpg) were removed for being non-free and lacking a rationale (WP:FUR). From where I stand including an image where possible adds to the list. Is there any way we could get these back in? --JorisvS (talk) 15:34, 3 January 2012 (UTC)

Sorting

Putting DP first messes up sorting by KBO, SDO, asteroid, etc., and does not even provide sorting by DP. (We can't sort by DP, as WP editors disagree as to which objects qualify as DPs: There are numerous sources that Sedna is a DP, for example, but that's not reflected in the sorting.) Also, the lists further down all sort by KBO, SDO, asteroid, so listing DP second makes the various lists consistent. — kwami (talk) 00:55, 11 February 2012 (UTC)

Reverted, and no, you disagree. The column sorts perfectly well for dwarf planets. --Ckatz^chat_spy 03:53, 11 February 2012 (UTC)

If it sorted, then the DPs would be listed together. But they're not, because we can't agree on which are DPs, because you refuse to accept any sources which disagree with your POV. We can, however, agree on which are KBOs and the like. And since that's how the other tables sort, that's how they should all sort. — kwami (talk) 05:30, 11 February 2012 (UTC)

I think the root problem is that the "type" column contains multiple axes of information. With the "shape" column, they try (inconsistently) to contain info about what the composition of the body is (star, gas, ice, rock), its dynamic status (sun, dominant body, satellite, small body), its dynamic group/location (e.g., planet, main belt, centaur, cubewano, detached, etc.), and its shape (H-E, unknown, potato). (Even more, with the binary indications and so on.) No matter how you arrange it, the sort will be wrong from some perspective. It doesn't help that the DP definition is a combination of dynamic status and shape, which are properties independent of each other. Anyway, reorganising those two columns into three or more that are focused on well defined, single axis properties is what's needed to improve the sorting. Tbayboy (talk) 06:41, 11 February 2012 (UTC)

Do we really need...

Do we really need the volume and surface gravity columns? And really need them twice? Would people really (regularly) use the volume figures, and if so, what is the added value of including these when the figure can very easily be calculated from the radius of the object? With densities often simply assumed (and usually arguably incorrectly assumed to be Pluto's) and radii often only approximately known, a surface-gravity figure would simply not be meaningful in the majority of cases. That said, I can easily offer two much more useful figures that are omitted from the table: semi-major axis and orbital period. --JorisvS (talk) 16:01, 27 April 2012 (UTC)

This is a list of solar system objects by size. Not by orbit. If we added orbital period and semi-major axis, this would not be a list of solar system objects by size; it would be a list of solar system objects. That in itself wouldn't be so bad, perhaps, but there's no point in listing an object by orbital characteristics if you can't order the list by orbital characteristics, and there's no point in ordering the list by orbital characteristics if all you will learn by doing so is which ones have the longest orbits within a certain size range. The only way to make this work would be to merge all the subsections into one giant list, and I don't think that list would be sortable.

The List of Solar System objects by orbit was supposed to be tackled once this article became a featured list, which was the goal established during the Solar System FTC ages ago. But since this list is now expanded beyond all redemption, I don't think it will ever be featured, so I have no idea when the ...by orbit list will be completed. As far as approximations go, nearly everything on this list is approximate. If we kept our list to well-established values, then Pluto would have to be taken out entirely. Really all that matters is that the list orders correctly; the important thing to take away from the Surface gravity list is that surface gravity is not directly tied to mass or size. I can take or leave volume. Serendi^podous 16:09, 27 April 2012 (UTC)

What about the Type of object column? Including semi-major axis wouldn't suddenly make this a list of Solar System objects by orbit (or at least no longer a list by size), otherwise this list would already be a 'list of Solar System objects by type' (or at least already not a list by size). It would then simply include information on the semi-major axis of the objects, just like it already includes info on the type of object (which I think would be useful to many users). Note that it would then still not fork a fully expanded '... by orbit' list. --JorisvS (talk) 17:36, 27 April 2012 (UTC)

Well as I said, there's not much point in having a sortable orbital list unless you can compare it to others on the list, and since the list is already broken up by size, the orbital stats won't reveal much. Look at List of moons for an example of how orbital stats can be sorted. Serendi^podous 18:15, 27 April 2012 (UTC)

Volume is a kind of size, especially relevent for potatoes, so I think it belongs here. Surface gravity (as much as I like having it) isn't, nor shape and type. I think some interesting non-size info is desirable (like the images), but which to choose seems pretty subjective. Given the images, I don't think shape is needed at all; you can see for yourself in the thumbnails. I think the earth-relative columns are rather useless, but they're at least on topic (size). The missing column I would like to see is H, even if it's not really a size measurement, since that's the only solid data for a good chunk of the TNOs and centaurs, everything else being derived from it by guesses about albedo and density. Tbayboy (talk) 00:32, 11 May 2012 (UTC)

For spheroids volume can be calculated very easily. On the other hand, for the potatoes volume figures are no longer given. Some of the images give the mistaken impression that their shapes are known to be spheroids, so I think the shape column is useful. I agree with you that it would be good to have an absolute-magnitude column. --JorisvS (talk) 11:08, 12 May 2012 (UTC)

Inconsistent referencing

Why do some objects have references attached to the numbers, but not others? The red-linked entries are obvious enough, but why do, e.g., Titan, Eris, and Pluto have references for their radii (that are the same size as on their main articles), but not Mars, Ganymede, nor Ceres? Rhea but not Oberon? Tbayboy (talk) 00:59, 11 May 2012 (UTC)

because this article is a mess. Wanna tidy it up? It'll only take about six months. Serendi^podous 07:55, 11 May 2012 (UTC)

Which way should it be? It would be easier (both to do and maintain) to not have a reference for fields that are in the body's article's infobox, but does that violate Wiki policy? If we must have references, would it be okay to put a single reference on the name (for well studied bodies like Jupiter), where that ref contains all the data? Tbayboy (talk) 14:01, 11 May 2012 (UTC)

A simpler solution would be to simply give the references their own box, as with List of natural satellites or Earth's location in the universe. Serendi^podous 15:18, 11 May 2012 (UTC)

Type of Object: Ixion

( any particular reason Ixion is listed as a KBO instead of a plutino? ) MistySpock (talk) 14:35, 18 August 2012 (UTC)

I have added that description to Ixion, ie (KBO—Plutino). -- Kheider (talk) 15:51, 18 August 2012 (UTC)

Centrifugal Force?

In the Surface Gravity paragraph, should it not be centripetal force and not centrifugal? The formula seems to suggest it's centripetal force as well. — Preceding unsigned comment added by 68.200.156.168 (talk) 22:53, 18 October 2012 (UTC)

Sorting by Type (100-50km and down)

[Please forgive me if I've done something incorrectly. This is my first time posting a comment; usually I just get fed up with trying and quit, but it kills knowing that I could contribute something, or bring it to the attention of someone who knows how.]

I noticed that, beginning with the 100 - 50 km radius list and down, there isn't an option to sort by type. I've found it pretty helpful in the preceding lists; I'm sure someone else would find it helpful if these lower lists had that function, as well.

I tried looking at the Beta edit, but couldn't see anything different aside from the fact that it looks like they aren't actually included in a column of their own, despite being separated as such on the display page. I'm pretty seriously afraid of messing around with the code, however much I /think/ I could handle it. (Like those slashes; are they going to italicize? I don't know!) Edit: No, they aren't, because this input box has that option right in front of my face.

Would greatly appreciate it if someone could tell me how to do this. Or do it themselves; I'm not picky! (adelaz) 75.66.200.203 (talk) 23:50, 23 September 2013 (UTC)

Fixed :-) Serendi^podous 18:32, 26 September 2013 (UTC)

Orphaned references in List of Solar System objects by size

I check pages listed in Category:Pages with incorrect ref formatting to try to fix reference errors. One of the things I do is look for content for orphaned references in wikilinked articles. I have found content for some of List of Solar System objects by size's orphans, the problem is that I found more than one version. I can't determine which (if any) is correct for this article, so I am asking for a sentient editor to look it over and copy the correct ref content into this article.

Reference named "brown":

• From Mars: Carr, Michael H. (2003). "Oceans on Mars: An assessment of the observational evidence and possible fate". Journal of Geophysical Research. 108 (5042): 24. Bibcode:2003JGRE..108.5042C. doi:10.1029/2002JE001963.
• From List of gravitationally rounded objects of the Solar System: Mike Brown, K. M. Barksume, G. L. Blake, E. L. Schaller, D. L. Rabinowitz, H. G. Roe and C. A. Trujillo (2007). "Methane and Ethane on the Bright Kuiper Belt Object 2005 FY₉". The Astronomical Journal. 133 (1): 284–289. Bibcode:2007AJ....133..284B. doi:10.1086/509734.{{cite journal}}: CS1 maint: multiple names: authors list (link)
• From Hydrostatic equilibrium: http://www.gps.caltech.edu/~mbrown/dps.html

I apologize if any of the above are effectively identical; I am just a simple computer program, so I can't determine whether minor differences are significant or not. AnomieBOT⚡ 20:24, 21 December 2013 (UTC)

Size of table cells

Rhea and Iapetus have larger cells in the table, compared to surrounding Titania, Oberon, Makemake, etc. I don't see a reason for this but I also don't know how to correct it. Rothorpe (talk) 18:37, 23 December 2013 (UTC)

Looks okay to me. Perhaps you're not expanding the screen wide enough: the comments section of Rhea+Iapetus will wrap to three lines high if the screen is too narrow, whereas the surrounding entries will stay at two lines high until very narrow. Tbayboy (talk) 01:25, 24 December 2013 (UTC)

I see now, thanks. Rothorpe (talk) 01:41, 24 December 2013 (UTC)

1996 TL66 could be included?

(15874)_1996_TL66 MistySpock (talk) 01:12, 2 July 2014 (UTC)

The article has undergone some heavy editing lately and it was removed. It was listed for years and can be found in some older versions. [5] Fotaun (talk) 22:29, 6 August 2014 (UTC)

Columns for eccentricity and distance from the Sun

Columns for eccentricity and distance from the Sun would be nice. If no one objects I might add those, starting with the planets.

Maybe some of the duplicated columns should be taken out? Maybe only keep mass, volume and gravity in fraction-of-Earth's units?

Liiiii (talk) 23:06, 22 March 2015 (UTC)

If dropping duplicate columns, I would rather keep the SI units. For mass, Earth units are meaningless for the smaller-object tables, and keeping it in SI makes it easy to compare across tables. I wouldn't object to dropping volume altogether, but if it's there at all, I would want the number that's more readily usable in a calculation, which I think is SI. (The idea of relative size is already conveyed by the radius-in-Earths column.) For surface gravity, Earth is close enough to 10 that comparison is easy in SI.

The table is about size, so I don't think orbital parametres really belong. But if adding them, why only distance and eccentricity? It also gets confusing with satellites, since they would need different units for distance, otherwise it becomes hard to read. Tbayboy (talk) 15:28, 23 March 2015 (UTC)

I agree with that the SI units are preferable. I don't see the added value of the surface gravity relative to Earth's. What about starting an actual list at List of Solar System objects with the following values? It would mean people can easily find these values, and so would not request them here.

Body	Image	Orbital area	Semi-major axis (km)		Eccentricity	Inclination	Mean radius (km)	Mass ×1021 kg (Yg)	? Mass (M⊕)	Density (g/cm3)	Shape	Rotation period (h)	Axial tilt (°)
			Distance to Sun	Distance to primary

Are there any missing? --JorisvS (talk) 16:40, 23 March 2015 (UTC)

Orbital elements belong in List of Solar System objects by orbit, which we haven't started yet, because we were supposed to start it after this got an FL. Serendi^podous 18:21, 23 March 2015 (UTC)

But there's snowball's chance in Hell of that ever happening. What about just beginning? What do you think of the parameters above? --JorisvS (talk) 18:37, 23 March 2015 (UTC)

If we added them, this wouldn't be a list of solar system objects by size anymore. Serendi^podous 19:05, 23 March 2015 (UTC)

This page would stay as is. JorisvS is talking about the already existing page (see above), which isn't currently in tabular form. This discussion should be taken over there (assuming Liiiii is okay with having the info there). That would be a lot of overlap, though. Tbayboy (talk) 19:16, 23 March 2015 (UTC)

Size ranking

Not going to continue an edit war about this but there are an couple of issues that I would like to discuss. First of all I think that an index column in the first table would be very useful but apparently there are editors with strong opinions otherwise. It would make it a lot easier to scan the table to find an object if you know their size rank rather than having to think down the radius column with keeping the radius in your head and continually calculating greater than/less than. Ordinal numbers are much easier to find that discreet values, even in an ordered sequence.

Second point is that the table uses radii rather that diameters. Many of the linked article, like Eris (dwarf planet), only mention the diameter in the lead section so you end up dividing by two on top of that (Yes, I know the radius is in the infobox but it is not easy to spot). Why does the table not use diameter anyway? People don't intuitively think in radii, but rather in diameters, which is what you see when you look and at any round object. The radius is not a visually recognizable property of a spherical object. Don't know about any else but I don't have x-ray vision myself.

The argument that the ranking/index would have to be constantly changed or updated sounds like a little laziness to me. The table has to be re-ordered anytime additional information changes the order anyway. I also get a feeling that some resistance to changing this may also be due to a little WP:OWN.

The only other way I can see to make it easier to find an object in the table would be to enable sorting by the object name column.

I started looking for a good source that would have the ranking and one thing I came across was this Top 20 list. Not exactly a reliable source and the order is the same only down to number 16 anyway. Also found this pretty picture but that list only matches to #16 also. I will bring up individual questions about that in a new section.

I don't realistically expect to see a consensus to change this but I had to express my options. Nyth63 17:08, 24 May 2015 (UTC)

If it is added (as a result of the discussion at Talk:Ceres (dwarf planet)), please put the rank column on the right side of the table, where it won't push more meaningful information off the visible edge of the browser window. Tbayboy (talk) 00:37, 28 May 2015 (UTC)

top 50

This is copied from discussion on the Ceres page. It's intended as a companion piece to the mass diagram. It's SVG, so you can edit it with a text editor and easily make changes for new size figures and ranking. Tbayboy (talk) 14:47, 7 June 2015 (UTC)

Significant figures

There are a number of numerical problems in the tables with Significant figures. In particular the mean radius given in a ratio to earth is very poorly calculated. Given that it is just a rough yardstick to help visual the size, I can accept that it is given with fewer digits as for example, the radius of Mars is given as 3389.5 km verses 0.532 Re (five digits vs three) but from Charon down it gets worse. There are only two digits given down through Ceres and only one for Sedna and the four below Ceres. Could someone recalculate these and give at least three figures for all of the numbers? And Makemake is blank in that column completely. Same issue with the volume and mass ratios also. Nyth63 01:41, 26 May 2015 (UTC)

I did the following based on the information from the corresponding articles on each object, taking into account error bars:

Sun: 109.30 ± 0.01

Jupiter: 10.9733 ± 0.0009

Saturn: 9.1402 ± 0.0009

Uranus: 3.981 ± 0.001

Neptune: 3.865 ± 0.003

Earth: 1.000000000000000 ± 0.000000000000000

Venus: 0.9499 ± 0.0002

Mars: 0.53202 ± 0.00003

Ganymede: 0.41345 ± 0.00005

Titan: 0.4043 ± 0.0003

Mercury: 0.3829 ± 0.0002

Callisto: 0.3783 ± 0.0002

Io: 0.28592 ± 0.00008

Moon: 0.272657

Europa: 0.24499 ± 0.00008

Triton: 0.2124 ± 0.0001

Pluto: 0.186 ± 0.001

Eris: 0.1825 ± 0.0009

Titania: 0.12375 ± 0.00009

Rhea: 0.1199 ± 0.0002

Oberon: 0.1195 ± 0.0004

Iapetus: 0.1152 ± 0.0004

Makemake: 0.112 ± 0.001

2007 OR10: 0.10 ± 0.02

Haumea: 0.097 ± 0.005

Charon: 0.0947 ± 0.0002

Umbriel: 0.0918 ± 0.0004

Ariel: 0.09086 ± 0.00009

Dione: 0.08812 ± 0.00006

Quaoar: 0.0871 ± 0.0005

Tethys: 0.08336 ± 0.00009

Sedna: 0.08 ± 0.01

Ceres: 0.0747 ± 0.0003

2002 MS4: 0.073 ± 0.004

Orcus: 0.072 ± 0.002

Salacia: 0.067 ± 0.004

I will update it accordingly. exoplanetaryscience (talk) 03:20, 26 May 2015 (UTC)

Omit the tolerances. You significant figures are still all over the place and very inconsistent. Pick a number like 3 or 4 and stick with it. Nyth63 13:33, 26 May 2015 (UTC)

That becomes difficult, as some objects have poorly-defined sizes (like 2007 OR10) so I can't easily define a constant figure without giving undue accuracy to some, or having few significant figures for others. exoplanetaryscience (talk) 13:45, 26 May 2015 (UTC)

The purpose of my original comment was to move the table towards being more readable, which with the last change it certainly is not. Removing the tolerances would help and that information is rather abstract in the secondary column anyway as it becomes a tolorance relative to the radius of the earth and not the object itself. Since the column is a calculation of size relative to the earth, that should guide the purpose of this column. Also, the calculation of figures is still a mess. For example, the radius of Pluto in km is given to 4 figures, but the Re is only 3. Titania is 4 vs 5. Salacia is 3 vs 2, etc. Again, as the actual known/measured/estimated radius is given in column 3, the purpose of column 4 I assumed was to give a "visual" reference towards earth and not just a repeat of the same data in different units which would be as redundant as also listing another column in leagues, rods or fathoms.. Having the same number of significant figures on every line would make it much easier to make this comparison in your head. If you are concerned with implied accuracy, then just round to three digits and go with it. If any one needs more accurate information they can just refer to column 3. Nyth63 15:17, 26 May 2015 (UTC)

I am also wondering if there is some miscommunication between significant figures and decimals here. A number like 123.4 has four significant figures as does 0.001234 and 1.000. I am an engineer and habitually think that way and I apologize if I was not clear what I meant. The wikilink should help clarify this. Nyth63 15:27, 26 May 2015 (UTC)

I attempted to round it to four significant figures, as that appears to be the maximum that is within the objects' diameter errors. Objects whose size errors are greater than this- Pluto, Makemake, 2007 OR10, Haumea, Charon, Umbriel, Quaoar, Sedna, Ceres, 2002 MS4, Orcus, and Salacia- were only included to the accuracy of their sizes. If that doesn't work, I could of course just use accuracy to 3 digits for objects smaller than Earth. exoplanetaryscience (talk) 16:59, 26 May 2015 (UTC)

It looks a lot better now but there are a few that I feel should be carried at least one more digit like 2007 OR10, Sedna and the bottom three. I understand your argument that the size tolerance offsets the last significant digit but they are still there and should be calculated that way.

Also, I don't think it would be harmful to round off the figures for Ariel, Dione, Tethys by one more digit. Do you think there may be room to add (approx.) in the column header?

Done, perhaps I should change Pluto, Makemake, and Haumea at this point? exoplanetaryscience (talk) 18:07, 26 May 2015 (UTC)

Looks greats now. I was not going to quibble over the last few but I think a clarification that these are approximate might be useful. Nyth63 19:29, 26 May 2015 (UTC)

Request to revert good-faith edits

In order to continue the overall revision of the tables in the article, Kwamikagami's good-faith edits need to be reverted to the version before this edit. His edits lead to a number of inconsistencies and are (currently) not helpful. I'm not going to argue about as to whether or not these edits make sense per-se, as it is not the time to restructure the article as long as I'm cleaning up the tables.

Whether or not the first three tables in the list should indeed be splitted/merged or not is something that may be discussed later on when the revision I've been doing is completed. (Also the question of whether to use radius or diameter may then be decided and implemented.) If so, then theses edits will have to be consistently made over the entire article (e.g. the "yottagram" paragraph in the lead) and not just in an ad-hoc manner. I'm not going to fight over this article. If everybody's happy with what Kwamikagami did, then I'm out of here. -- Rfassbind -talk 14:06, 24 July 2015 (UTC)

What in the world is your problem? How do my edits have anything to do with yours, or cause you the slightest inconvenience? If you're going to pout and go home because you're not alone in editing this article, then you don't belong here. — kwami (talk) 18:51, 24 July 2015 (UTC)

Very aggressive and unconsidered reaction. I already explained myself twice. Maybe your time has (finally) come to go somewhere else, ever thought of that? Rfassbind -talk 23:12, 31 July 2015 (UTC)

Moons vs Satellites?

The designation between moons and satellites on the tables on this page seems arbitrary and should be unified under one term or the other. I always understood the two to be reasonably interchangeable, however the inconsistent manner in which they are used on this page suggests a scientific or technical difference exists between the two, where I'm not sure one exists.

Google's definitions for the two words seems to suggest that the objects should be termed as moons when orbiting a planet, with satellites being objects orbiting smaller bodies; One of Google's definitions for moon being 'the natural satellite of any planet', and of course the capitalized version of Moon referring specifically to Earth's Moon. Indeed, Wikipedia's own entry on Natural Satellite implies the requirement is only 'a celestial body of greater mass' instead of a planet, so there is some inconsistency in definition between sources.75.171.87.102 (talk) 00:35, 17 March 2016 (UTC)

The biggest issue though is that the Moon has the sun as it's primary and the earth as a local body. The math shows that the Moon has a higher attraction to the sun that to the earth and is drifting away from earth. The moon has not been captured by the earth. The term moon should be replaced with satellite everywhere to avoid future arguments like with Pluto. Also the first graph categorizes objects as solar orbit or satellite: the moon has a solar orbit. 198.103.184.76 (talk) 19:40, 23 February 2017 (UTC)

Given where we are, I feel compelled to ask you for a reliable source for that assertion that the moon orbits the Sun rather than the Earth, and that it is drifting away from the Earth for any reason other than entirely normal tidal braking and momentum transfer (which is also slowing the Earth's rotation), which has also cause the the moon's near-total (but for some slight libration) tidal locking. It's an extraordinary claim, and so requires extraordinary proof. Luna, when compared to Terra, is one of the larger satellites in the solar system, and the bodies' mutual attraction helps to keep them together, and orbiting a barycentre barely within Earth's crust (and thus not quite qualifying as a binary system instead of planet and moon - but nearly, oh so nearly), despite being much further apart than e.g. Pluto and Charon.

I mean, of course the moon is attracted strongly towards the sun, all objects in the solar system other than very temporary visitors like `Oumamama (or however it's written) are, but that doesn't mean it's going to be pulled away from the Earth when its otherwise following the exact same average orbital path (same average distance from the sun, same average speed and orbital period around it) and that part of its celestial mechanics doesn't depend on either its own mass (doesn't matter that it's 1/80th of the Earth's mass - it's the Sun's mass that's crucial to how both objects orbit, so they orbit the Sun the same way), or the presence or absence of a large, nearby, and locally more influential body. The Sun's pull acts equally on both Earth and Moon, so can be cancelled out when it comes to considering how those two interact with *each other*.

And in that interaction, the Moon very definitely orbits around the Earth, and in fact the Earth very slightly orbits around the Moon, too. It's not just the large bodies of water on our planet that are pulled by the Moon (the Sun has *some* influence, hence neap and spring tides, but it's the moon that has the primary influence, which is why tides follow a roughly 12 and a half hour cycle, not an exactly 12 or 24 hour one... add up all those not-quite halves, you get it sliding backwards by a whole day every 28 days... or exactly the amount of time the moon takes to complete an orbit), but the entire planet, in a measurable and indeed already carefully measured way.

The sun is no more going to pull the Moon away from the Earth any more than the Earth might pull a satellite put into Lunar orbit away from the Moon. Or disrupt any other sub-system you care to mention. The sun's influence is cancellable, up until the point where the orbit is somehow independently disrupted to the point where the supposed planet and satellite are no longer following the same average solar orbit (and that influence would lead to their relationship being disrupted even without the sun being present), so the sun's gravity affects them differently over significant astronomical time and leads to their orbits diverging ever further. Without there being something else extremely massive passing quite close by at just the right time to impart sufficient fling to the moon - but no corrective opposite influence a certain time later - to wrench it from Earth's grasp in a single momentous event, it's not going to just randomly wander off. It's too close, the two bodies are too massive, and are moving too slowly in relation to each other for that to happen. 146.199.0.203 (talk) 01:21, 3 March 2018 (UTC)

While the three body problem doesn't have a closed form solution, and so it is possible that a system that seems stable actually isn't, it doesn't seem likely to happen anytime soon. (That is, within the lifetime of the Sun, for instance.) While the moon causes the tides, it is mostly from the earth's rotation, and so the moon can gain energy and orbital angular momentum through tides. I suspect that isn't enough to escape, but you might want to find someone who knows orbital mechanics better than I do to explain it better. Note that astronomers didn't used to believe that a planet could orbit two stars (suns) at the same time, but now one has been found to do that. Gah4 (talk) 21:57, 23 February 2017 (UTC)

Graphical overview 1st diagram has wrong scale for the Sun

Diagram topmost values (left side) of 360000 and 400000 should be 1360000 and 1400000 respectively. Sorry not to have done it myself but I do not have the graphical tools for that.

Reduce 200-400 km section?

The section with sizes from 200km to 400km radius is overwhelmingly dominated by transneptunian objects, about which there might be some knowledge in some cases, but I think not enough to warrant listing volume, surface gravity and Earth comparison values. But there are values for a lot of TNOs, and often they don't even match the values they should have according to the radius given. I would prefer if the section columns were reduced to those of smaller sizes, plus density as that may be known in some cases.

On the other hand, I think the section should contain all known objects of the size, and not just a selection like with smaller sizes. Brown's list contains 72 TNOs in the ranges between 200km and 400km radius. If people think that's too much, then maybe move the lower limit to 250km; for that value there are just 37 TNOs in Brown's list, the other 35 are estimated between 200km and 250km radius. Ambi Valent (talk) 21:25, 8 April 2014 (UTC)

If people think it's OK, I could update the section (once there's an agreement about what I'm allowed to do). Ambi Valent (talk) 21:56, 8 April 2014 (UTC)

Another possibility, to cut down a bit, would be to list only named objects, or only cis-Neptunian, or only cis-Neptunian + satellites (for Pluto's moons). BTW, if we don't know the radius accurately, it's a bit meaningless to compute area or volume; if we do, we need to include the precision. — kwami (talk) 00:12, 9 April 2014 (UTC)

There's a greater problem, that nearly all of the data is wrong. For example, much comes from the JPL Small-Body Database Browser. They give all figures to a precision of ±10 meters. We only know the size of Vesta to ±100 meters, and that's after orbiting it for a year! Now, maybe JPL provides the uncertainties in another column, or if you're accessing it you're expected to know what to do with the data, but for us, simply regurgitating the figures is unacceptable. I'd be willing to bet my life savings that any one of these is wrong. For example, we give the radius of 1021 Flammario as 49,695 meters, when the margin of error according to our article is almost 2 kilometers: The chance of it actually being 49,695 meters is minute. We give 2003 AZ84R as 363.5 km, when the true error is almost a thousand times that. Any figures without error measurements should be deleted, or at least rounded off to the nearest 10km for smaller bodies and 100km for larger ones. — kwami (talk) 22:15, 8 April 2014 (UTC)

How about breaking it into two lists: one a selected list of objects with measured sizes, and another, overlapping list of those objects that are just assumed from magnitude. The magnitude list would contain only magnitude, size range (for some consistent, stated albedo range, like .05 to .25), and type of object. The selected list would stay as is. Tbayboy (talk) 03:51, 9 April 2014 (UTC)

I changed the assumed sizes to "unknown", and there weren't very many of them, so there's not much of a gap for a second list to fill in. (Though I was going off our articles, so there might be others I missed.) Maybe we could list them as "assumed X–Y", where X and Y are calculated from the albedo range? — kwami (talk) 05:40, 9 April 2014 (UTC)

I like the inclusion of uncertainties. There is one problem with just listing "unknown": there is then absolutely no reason why it should in a certain position in this list, or even subsection. With an estimate with huge bounds, at least we have a way determining where in the list we'd have to put the object. Maybe we could list H and known/assumed albedo in separate columns? --JorisvS (talk) 12:43, 9 April 2014 (UTC)

Note that there seem to be at least a dozen more that are assumed sizes, the "largest" being 2006 QH181. I agree with JorisvS re "unknown". Kwami's "assumed" sounds good to me, although maybe 300±100 is a better way to express it than 200-400, since it then makes the position in the list a bit easier to see. Tbayboy (talk) 13:18, 9 April 2014 (UTC)

Agreed that "±" is better. It is hard to handle such poorly constrained sizes well. What would you realistically take to be the minimum and maximum values? --JorisvS (talk) 13:43, 9 April 2014 (UTC)

Salacia is around .04, Orcus ~.25, Sedna ~.32, and the Haumeans much higher (maybe they can be handled separately). 2002 MS4 and 2002 XV93 are also dark, in the .05 ballpark. So I would guess that .04-.5 would capture almost all, and .05-.25 would still get most (since smaller ones <1000km are less likely to be bright). To find out, run down the list for (say) 6 > H > 3 that have good measurements (IR or occultation -- i.e., error bars within 10%) and see what the albedo range looks like. I think one of the TNOs are Cool" papers might have a nice table with this info (I'll look this evening). Tbayboy (talk) 16:50, 9 April 2014 (UTC)

Took a look around: Brown's DP list has the info (abs mag and albedo) right there. I just ignored the "estimated" entries, except I also dug out a few of those for which there are radiometric measurements from TNOs are Cool. Of the 46 I tallied in the H=3.0-5.9 domain, 5 were Haumea family (albedo ~70%), 4 have > 20%, 1 > 30%, none < 4% (although several = 4%). So an albedo range 4-30% seems reasonable. Excluding Haumeans, the overall average albedo is 12%, with 15% for H=3.x, 12% for H=4.x, 11% for H=5.x. So 12% looks like a good nominal albedo to use for sorting purposes if you want to get fancy. With albedo=12%, H=4.9 is 402km diameter, and H=3.4 is 802km. So TNOs in that H range (with no other size measurements) would be in the 200-400 radius table, lower Hs in the 400+ table, and higher Hs in the smaller-size tables (if at all). Tbayboy (talk) 00:50, 10 April 2014 (UTC)

I only used ± when that was in the source. Otherwise I gave a typical range, so as to avoid OR as to what the median should be. (I don't mind converting, as long as there are more minds involved than just mine. I think differentiating assumed ranges from measured ranges is important, though.) "Unknown" was only meant to be temporary. One of them, BTW, is given as unknown because one of our sources appears to have a typo. — kwami (talk) 02:06, 10 April 2014 (UTC)

Good point. A note above the table could make clear that the ± is for measured sizes and the range is for assumed. What's bugging me is that the column is sortable, and X±Y doesn't sort well with X-Y. The "ca." also throws off sorting. On the other hand, the list is supposed to be sorted by radius, anyway, so maybe there's no need for that column to be sortable. Tbayboy (talk) 03:25, 10 April 2014 (UTC)

What's with all the "citation needed" for the mean radius numbers of the planets? I presume the numbers were taken from the planets' articles, and there is a citation for radius - except that the articles only use polar and equatorial radius from that source, but ignore the mean radius. Ambi Valent (talk) 21:30, 9 April 2014 (UTC)

Exactly that: The mean radius should be in the main article. 'Citation needed' was a reminder that we don't have a source for the figure. Also, "±?" for figures which are likely to be precise but which don't have their precision listed in the main article. — kwami (talk) 02:06, 10 April 2014 (UTC)

Then the main articles should be fixed. The source given for polar and equatorial radius numbers in these main articles also contains mean radius numbers, but they are missing in the main articles. But I notice now that whoever copied the numbers from that source made changes on his own to the last digits of those numbers instead of copying the actual numbers given. Ambi Valent (talk) 07:25, 10 April 2014 (UTC)

I added main radius data to the planet main articles, put in the numbers from the radius source, and put those numbers in into the table over here, removing the cn tags. Ambi Valent (talk) 19:16, 10 April 2014 (UTC)

Maybe we could update {{Listrow}} to accept Δ_r and Δ_m? — kwami (talk) 03:16, 10 April 2014 (UTC)

While we're on the subject Kwami, do you think you could reorder the Moons graph in order of size? I didn't want to bring this up, because you did such a good job on all those mass graphs, but it's always kinda triggered my geek order reflex. Serendi^podous 04:20, 10 April 2014 (UTC)

Note that they're in order of planet, so you can see the fraction of Saturn moons vs Uranus moons. Although those fractions aren't complete, they're pretty close. Tbayboy (talk) 13:14, 10 April 2014 (UTC)

Yes, that's what I was going for. The solid-bodies graph orders by mass, which I agree is also nice to have. — kwami (talk) 02:19, 11 April 2014 (UTC)

There was only one red link, so I created a stub at 2010 VK201. However, I can only access the IAU discovery announcement. I added a link to a more recent article, if s.o. here can access it and update the stub. Also, at List of possible dwarf planets there are several other objects in this H range, and one a bit brighter, so those should presumably also be listed here, if we want this list to be complete above r=200km. — kwami (talk) 03:47, 11 April 2014 (UTC)

The problem with that section is that there are 8 objects with "Unknown" as their radius. I don't think "Unknown" qualifies as 200-400 km. Though there are also sorting errors, for example 250 km between 350 and 340, and 170 above a "ca. 300". 85.217.44.90 (talk) 01:35, 8 August 2014 (UTC)

The standard approach to that seems to be to use the absolute magnitude (worked from apparent magnitude and best estimate of distance, where that's actually known well enough) and a default, quite high value (I guess something like second standard deviation/90th percentile amongst all the properly known values?) for the albedo to calculate a reasonably firm *minimum* figure for the possible size (as a very reflective object will be brighter for the same size, and smaller for the same brightness) as a backstop, then try to either directly measure it with submillimetre arrays or stellar occlusion observations for a better estimate of the true size, or try to make a better estimate of the true albedo (using spectrographic or even just gross colour dimension studies, particularly redness vs blue-ish-ness, as there seems to be a fairly reliable trendline connecting that relationship with overall reflectivity) and thus adjust the size - most likely upwards, by as much as 10x in some extreme cases, but sometimes downwards *a little* - based on that and the already known magnitude.

Therefore using those more modern techniques there shouldn't really be any "unknown" size objects any more, unless the observations of them are so limited that we don't even really know their current orbital radius and position, and thus distance from Earth... and in which case, we're likely to lose track of them completely in short order anyway. Just a whole bunch of them listed with diameter being "at least X kilometres". Which isn't a great basis for sorting the list, but it gives at least some scant ability to decide whether an object should fit into the list anyway (if there's a minimum size cutoff), and roughly how high up it should be, with the position further refined (likely moving upwards) as more information comes in. Additionally it could be argued that the more we know, and more accurately, about a particular object, then the more "interesting" it becomes, and the more it maybe deserves (from an anthropocentric, astronomical viewpoint) to get a more prominent position on the list. Until we know for certain, it can be stuffed in at the position equal to its likely minimum size, with that "this is a lowball estimate" caveat added on to it... 146.199.0.203 (talk) 01:48, 3 March 2018 (UTC)

Radius vs. Diameter

I thought it was odd that this table uses radius rather than diameter as the primary measurement. Apparently I'm not alone, as Nyth mentioned this above. I also noticed, while clarifying estimates for the size of Pluto's moons in the New Horizons article, that at least some of the figures given in this table are already diameter rather than radius. No doubt the editors who added them made the same intuitive leap. At the very least these need to be checked. Now, I don't precisely object to having radius as a measurement, if astronomers find it useful, but I think that the primary measurement should be diameter, since this is what most people expect. I also realize that many smaller objects aren't perfectly round, but this affects estimates of radius as much as it does diameter. I propose adding diameter to the table, alongside radius. I understand that it's a simple matter of multiplication, but readers shouldn't have to do figures in their heads, assuming they remember their geometry at all. P Aculeius (talk) 13:02, 27 May 2015 (UTC)

I've been noticing this, and the sometimes egregious errors in stated size, more and more whilst mooching through particularly the individual dwarf/potential dwarf/notable minor planet articles. Sometimes (far too often) there's even a kilometre figure listed simply as "size" without clarifying which it is, and when you check citations (or google for more info where the citations are lacking) it's a coin flip as to which one it is when you find more scientifically rigorous data.

I'm not really sure how it can be fixed, without setting some fairly strict and draconian rules on how articles about and data regarding celestial objects should be entered, and launching a major whole-site initiative to pull together as many people as possible to exhaustively go through each and every one of the 450,000+ articles (many no more than stubs) checking and correcting the formatting and data within it. It's far greater a job than could ever be completed by a single editor, or a small group of maybe a couple dozen, and certainly not within any kind of reasonable timescale. It's a massive problem that needs a massive effort, maybe bolstered by some very cleverly programmed bots. 146.199.0.203 (talk) 01:28, 3 March 2018 (UTC)

I have often wondered why planet infoboxes like Earth show radius instead of diameter. For Joe Q. Public I have always thought diameter would be assumed by a casual reader. -- Kheider (talk) 13:58, 27 May 2015 (UTC)

I am guessing, that from a mathematical view, the equation for volume using the radius rather than diameter, has one less term in it (1/2), that that is used for calculations preferentially. Then you don't have to remember to convert. But radius is definitly less intuitive. You would never give the size of sports balls of any type by its radius. Nyth63 17:05, 27 May 2015 (UTC)

The annoying thing is that mathematically the radius is the primary useful value, but intuitively it's the diameter. And having both would be incredible overkill. Is something fancy where people could switch between the radius and diameter values in the same column possible to make? --JorisvS (talk) 18:47, 27 May 2015 (UTC)

I'm not an expert on wikipedia's programming languages, but I would say that with a more advanced language it would be fairly easy to do, but considering the simplified language wikipedia editing uses, such a thing would be possible, but not simple. exoplanetaryscience (talk) 18:55, 27 May 2015 (UTC)

If we could pull that off (with help from somewhere), it would solve the issue. --JorisvS (talk) 19:12, 27 May 2015 (UTC)

Anyone who knows how to calculate the volume of an object using its radius already knows that the radius is exactly half of the diameter. The goal of Wikipedia is to make information accessible, not to cut as many steps as possible out of technical calculations. Especially when the volume is already given in the table using two different measurements, obviating the need to calculate it. The radius may be more useful for calculating volume, but it's only marginally so. Diameter is far more useful for giving the reader a notion of scale. If we have to choose one or the other, it should be diameter. P Aculeius (talk) 03:29, 28 May 2015 (UTC)

The problem really is that there are an awful lot of celestial objects that have simply a "size" listed (literally that word), without it being defined as either radius or diameter, and there certainly doesn't seem to be any prevailing standard for which of them it is. You're about as likely to find one as the other. Seems like WP maybe needs a proper style guide for defining the characteristics of Things In Space, particularly on that recommends hitting anyone who just says "size" with a hefty cluebat. If it was simply a case of there being 50% that outright state "diameter", and another 50% that state "radius", it wouldn't be so bad, and although continually having to do mental arithmetic to convert half of them to your preferred standard (and occasionally forgetting to do that and getting it wrong), at least you could then be more sure what the correct figure (or estimate) actually is. (...worse, I'm pretty sure I've seen a few where it is stated, but the author has incorrectly assumed an unclear source is one or the other, so the figure is precisely defined, yet still inaccurate by a factor of 2 one way or the other) 80.194.203.132 (talk) 13:48, 1 August 2019 (UTC)

The confusion has corrupted this list as well: the erstwhile critical dimension for HE is 400km in diameter, and we separated the list at 400km in radius, making the sections meaningless. I did a half-assed job stitching them together, but they have different numbers of columns. I think we should break the list at r = 750km (separating Rhea in HE from Iapetus not in HE) and again at Brown's estimate of r = 200km. The third break should be at the point where we no longer try to list everything. — kwami (talk) 01:55, 24 July 2015 (UTC)

@Kwamikagami: Thank you for that very inconsidered crashing of the editing I've been doing now for several days. As of now, I cease any further amendments to the list, before I completely lose my temper and add to the confusion that obviously already exists. Rfassbind -talk 02:25, 24 July 2015 (UTC)

I didn't change any of your edits, so I have no idea what you're talking about. — kwami (talk) 02:37, 24 July 2015 (UTC)

Was this re-arrangement / repair job ever completed, or a fresh attempt made after this point? It's been 2 1/2 years since the last comment, after all, and the list still seems to break at 400km then 200km then 100km radius. And I'm sufficiently confused now that I don't know if that's correct or not. But I do know that neither 750 nor 375km appears there. 146.199.0.203 (talk) 01:31, 3 March 2018 (UTC)

cubic megameters

• I would suggest changing the SI units provided for volume in the first table to cubic megameters (Mm³) instead of billions of cubic kilometers (10⁹ km³). Otherwise you have the nonstandard usage "Jupiter is 1.4 million billion cubic kilometers (1.4 × 10⁶ × 10⁹ km³) in volume" as opposed to the standard usage "Jupiter is 1.4 million cubic megameters (1.4 × 10⁶ Mm³) in volume." Nicole Sharp (talk) 11:43, 17 October 2016 (UTC)
• Masses should also be in yottagrams (Yg) for the first table. Right now, there are badly mixed metric units being used. Metric units are presented in the first table using three different metric systems: centimeter-gram-second (CGS, with grams per cubic centimeter for density), meter-kilogram-second (MKS, the SI standard), and kilometer-tonne-second (KTS: if the kilometer is used as the standard unit of length, then the tonne [megagram or metric ton] should be the standard unit of mass, and density then in tonnes per cubic kilometer). Nicole Sharp (talk) 12:09, 17 October 2016 (UTC)

There's a bit of a problem with the MKS system, even though it should be the universal standard, in that it pretty much mandates slipping into some other variant, because of the messiness of constructions like giga-kilogrammes, so any practical notation is forced into being some kind of non-SI amalgam of more easily written and spoken units... unless of course you stick strictly to standard form and ten-to-the-power-whatever kg, which obviates the issue completely, but isn't the fastest to write with a regular keyboard.

Personally, when drawing up a table of objects using WP derived info, I've used Tonnes as the basis, with Giga- thru Zetta- (and Yotta, for the sun only) prefixes as appropriate, because that's the neatest and easiest to mentally visualise, but your suggestion of basing on grammes could also work, with a 10^6 adjustment in magnitude... the only issue with that is that we hit the largest currently available prefix, ie Yotta-, rather too early and have numbers growing into tens of thousands or even millions of yottagrammes when the idea of magnitude prefixes is to constrain figures within the 1.0 to 999.99 range (1.21 gigawatts in place of 1,210,000 kilowatts, for example). Whereas tonnes (ie, kkg, or Mg) fit the range of trackable objects hurtling around the solar system quite nicely... the smallest in Earth orbit being around 0.01t, and the sun being roughly 2000Yt.

However, there's no equivalent single-word, single-letter unit equal to 1000 km, so for physical dimensions and distances, Megametres (and for larger distances, AU) have had to serve, and terrestrial Years for orbital periods (seconds would be ungainly and basically useless in terms of making any sense, though I've seen spacey sci-fi settings where they use SI prefixes with seconds to define non-Earth-centric time units, like kiloseconds instead of hours and megaseconds instead of weeks; days might work rather better, but are still arbitrary and terrestrial anyway, and ultimately themselves rack up indecipherable figures pushing into the hundreds of thousands once we pass beyond the Plutoids). So the system is a sort of weird (mega)Metre-Tonne-Year setup. As it's designed for human reading, rather than calculating things inside a database that would reformat for display anyway, it serves alright. If you were intending to use the data for actual scientific purposes, rather than encyclopaedic reference, you'd of course convert it back into MKS first, and probably use a better, preconverted/preformatted source for it anyway. 146.199.0.203 (talk) 00:53, 3 March 2018 (UTC)

Without commenting on Yg or the other units, CGS is commonly used in describing electromagnetic units. Density is commonly in g/cm³, or relative to the density of water, at least for ordinary solids and liquids. Not so obvious for things like neutron stars, where it might make more sense to compare to the density of the sun. (Since mass and distance have their own standard, the density of water might be slightly different from 1, but should be close enough for this discussion.) Gah4 (talk) 21:18, 23 February 2017 (UTC)

Just as a further postscript to this, I find myself wondering at why only the largest objects - no smaller than maybe Iapetus - have a volume figure given, even though that figure is actually more useful for sorting the *smaller* objects, whose sizes might not be easily expressible in terms of a single radius (or diameter) and hard to come up with a consistent average for (particularly, do you use arithmetic or geometric mean of the dimensions? some other method?), but having a fair estimate of the total material volume enclosed by the surface ... a certain "amount" of celestial play-dough, if you like, which may be of some arbitrary type with variable density, but can only be squashed into a particular volume, though that may be represented by any kind of weird irregular shape, or a more-or-less-spherical potato. But still made of the same particular amount of play-dough, which gives us a nice easily handled single number that the blobbier objects can be sorted by quite simply, instead of fussing over whether to go by average radius, or dimensions (which can be just one, two, or three figures, all of which can be very different), etc.

Most of the individual article pages for at least the midsize objects seem to include a volume figure (estimated to lesser or greater degrees of precision), so would it be worth adding this in for the end of the above-400km section and at least some of the sub-400km ones? 146.199.0.203 (talk) 02:28, 3 March 2018 (UTC)

Missing bodies

• trinary Lempo / 1999 TC36
• Farthest Object in the Solar System - V774104 — Preceding unsigned comment added by Gann123 (talk • contribs) 19:36, 13 December 2018 (UTC)
• others? — Preceding unsigned comment added by MistySpock (talk • contribs) 18:37, 17 October 2017 (UTC)

Density of 20000 Varuna

With radius of 310 km, mass of 0.37x10²¹kg, Varuna has density of 2.965g/cm³, but the source here (abstract / PDF) tell me that it has density of 0.992g/cm³. Newone (talk) 03:37, 4 August 2010 (UTC)

Ok, changed the values for Varuna and Haumea to that source. Fotaun (talk) 16:05, 3 March 2011 (UTC)

But has that made the mass incorrect, now? 146.199.0.203 (talk) 01:58, 3 March 2018 (UTC)

I recently did a lot of work on the Varuna article, as it had ... considerable problems. I'm not 100% sure where the "3.7 x 10^21 kg" estimate came from, but there's now a much more realistic one on there (added independently of seeing this complaint, which I literally only just ran across now), more in the region of 1.6 x 10^21 kg instead.

I do wonder if whoever worked the 3.7 figure out made the same daft mistake I did at first, figuring out the mass of a cube with sides the same length as the object diameter, instead of using the radius and the usual volume-of-a-sphere calculation, which means you overestimate by almost 2x. Bearing in mind that using the equivalent-area spherical size estimate (which is what seems to be used by most professional astronomers publishing papers about minor planets / TNOs) would still get the volume (and thus mass estimated from density) wrong; instead, for any object that's not wholly or near-as-dammit spherical, you have to use the dimensions to get the volumetric mean (...which itself is no good for giving an equivalent diameter estimate because it gives a different surface area vs a sphere of the same volume, and it's the area we're actually interested in for astronomic measurements, as it's that which reflects the light that most of the estimates are based on).

...which is a realisation I only actually came to recently so I've got a load of edits to go back over, maybe including Varuna, to re-revise mathematically derived mean diameter and/or mass estimates on.

tl;dr, argh, my head 146.199.60.87 (talk) 13:56, 13 August 2019 (UTC)

Binary/trinary

Just curious, why are these listed as part of the descriptors for some of the dwarf planets? I was under the impression that the terms usually referred to a situation where the object and its moon are close in size. --Ckatz^chat_spy 20:23, 18 September 2011 (UTC)

Not for asteroids. E.g., see Johnston. It's probably just tradition, back to when they had little idea of the sizes. Tbayboy (talk) 21:57, 18 September 2011 (UTC)

Technically even Charon is only a satellite. (B=Binary companion / S=satellite) See also (90) Antiope and (93) Minerva on the list. -- Kheider (talk) 00:00, 19 September 2011 (UTC)

Thanks for the quick replies, and for clearing it up. --Ckatz^chat_spy 08:46, 19 September 2011 (UTC)

The impression I get from relevant articles, particularly that for Pluto and some similar ones, the determinant is now more where the system barycentre sits, ie the "centre of gravity" which all of the objects in a particular system orbit around. If it's inside the primary object of a system, then it's traditional sun-planet, planet-moon, etc. If it's outside of the primary (above its surface, like), then it's a binary. So technically Pluto-Charon is binary, though that's a recent enough discovery that it's not really been made official and might take some time if it ever happens. Earth-Moon is *nearly* binary, but avoids qualifying by a couple dozen kilometres. Sila-Nunam is very definitely binary (having fairly close sizes and about a 2:1 mass ratio also helps with the decision). And in fact Sun-Jupiter would count as some kind of binary star system if only Jupiter was somewhat hotter and more radioactively active, to the point where it counts as a brown dwarf or other quasi-star, because the barycentre of the two actually sits outside of the Sun's nominal surface (and of course, outside that of Jupiter)... it's just we don't really yet have any technical way of categorising binary systems made of a smallish star (like our yellow dwarf) and a suitably supermassive planet orbiting it, or any other heterogenous binary (or trinary, etc) systems for that matter. 146.199.0.203 (talk) 01:57, 3 March 2018 (UTC)

How up to date / reliable is this list? (at time of asking, ie start of March 2018)

I only ask because I've been trying to work up some kind of manageable list of the top 100 or 200 things to put on a more comprehensive solar system map than the classic versions... and amongst them we have Haumea at #19 according to this list, and (145453) 2005_RR43 - another member of the Haumeid family - at #120... but nothing else from the Haumeids (or certainly, nothing else from the list of ten members estimated as largest after Haumea itself, on the Haumea Family article page) appears anywhere on the list. At all. By either their discovery serial code, or minor planet registration number.

That's at least eight TNOs sharing a similar orbit to Haumea and average radii of more than 85km, up to more than 160km, plus another of about 36km, that have been left off the list. At least two, maybe four of them occupying the ground in between the current #19 and current #120 off a list of roughly 300. Biiiiit of a glaring omission. And begs the question of whether there might be a lot of other objects of that size, maybe even greater, that have been omitted.

One or two might be understandable, but nine is a bit much, especially as none of them are recently discovered - the dates for these ones are all no later than 2005, and range back to 1995... so they've been known about for 13 to 23 years... and are members of a reasonably notable orbital family... how many others are out there that should also be on the list?

And really, how do we even properly keep track of such a sprawling list and verify its data in any kind of organised and usefully frequent manner, when there's about half a million potential entries to select the actual top 300 or so members from and keep the most recent astronomical data refreshed for? 146.199.0.203 (talk) 00:32, 3 March 2018 (UTC)

The line that Ceres is on does not have a darker background.

The other 3 Belt asteroids do. Will this be changed? — Preceding unsigned comment added by 2606:A000:1014:C2FC:0:5837:B088:A394 (talk) 03:31, 20 August 2018 (UTC)

Unlikely, as it's no longer considered a "belt asteroid" - it's a Dwarf Planet (the only one in the main belt, with even the largest "other" asteroids all being much smaller), and therefore should be, as it is, coloured the same white / light grey as the other four. Same way that the confirmed Kuiper Belt DPs aren't coloured the same as their asteroid and comet neighbours. 80.194.203.132 (talk) 13:40, 1 August 2019 (UTC)

Articles needed for objects

2001 QC298 and 2001 QC298 I (not sure about the spelling of the second object) are the only objects on the list without their own article. Both are very similar in name. I am glad to make the articles if anyone can give references to create them.--Wyn.junior (talk) 21:47, 5 February 2019 (UTC)

Seeing as the naming of the latter suggests it's the moon of the former, you probably only need one article, with the second one being a subsection within it... 146.199.60.87 (talk) 13:44, 13 August 2019 (UTC)

Numbering

This entire list should be numbered with 1 being the largest and the biggest number being the smallest.--Wyn.junior (talk) 17:53, 6 February 2019 (UTC)

It's not very useful (beyond the first 20 or so) since the sizes are not that well known for most of the minor planets. That is, the sizes listed are often very approximate. At the smaller end (less than 200), this is not a complete list, just a list of the interesting or well-studied objects. Tbayboy (talk) 21:50, 6 February 2019 (UTC)

I disagree. A numbered list would at least give us how many objects there are listed.--Wyn.junior (talk) 15:49, 7 February 2019 (UTC)

What use is that? It's a list of selected objects, not all objects (billions), not even all known objects (hundreds of thousands). That is, "the number of objects that some wikipedia editors thought might be interesting". Tbayboy (talk) 17:13, 7 February 2019 (UTC)

You are correct. Nevermind.--Wyn.junior (talk) 20:21, 7 February 2019 (UTC)

There is actually a numbered list elsewhere on WP of all the known MPs plus their moons (on top of the sun plus 8 major planets + THEIR moons), which runs to many, many thousands of pages. Trying to replicate it here would be insane. However, it is quite a nice thing to have for the (confirmed or at least strongly suspected) larger objects, allowing us to easily count how many bodies of reasonable note are in our neighbourhood, rank them, and compare where various familiar examples fall on the list relative to each other. 80.194.203.132 (talk) 13:38, 1 August 2019 (UTC)

Edit: many hundreds of pages (at least 524 so far), but each page has 1000 entries... and it's linked from this page, IIRC. 146.199.60.87 (talk) 13:43, 13 August 2019 (UTC)

Almanac needed

Does anyone know of a an Almanac with the full information for this article so each of the objects can have the full same info and possible one long continuous list sortable in any you want?--Wyn.junior (talk) 20:52, 6 February 2019 (UTC)

There is no such almanac. The missing fields are missing because they're not known. Even many of the filled-in fields are just guesses. Tbayboy (talk) 21:52, 6 February 2019 (UTC)

Yeah, I'm yet again trying to use the available information to put together a nice pop-sci "map" of the 100 largest objects in the system and being stymied by multiple heavily conflicted measurements, and having to manually average out the most likely accurate ones (not always the ones stated on this particular list and used for its own sorting...). Our astronomical ability has undergone revolutionary improvement over the last 25~30 years, but it's still far from perfect, and there's just too much stuff to re-survey and not enough available observatories - or decent observational opportunities - to keep the updates flowing at a sufficient speed to properly nail everything down within less than probably another 25~30... For now we just have to, as has been the case all along anyway, go with the best guess. And encounter endless arguments over which of the many guesses is actually the "best". 80.194.203.132 (talk) 13:35, 1 August 2019 (UTC)

(Update: at this point, I'm pretty much thinking that I'm gonna have to make an error-bar chart for almost everything smaller than Pluto, save for the most well-studied major-planet moons, and see what kind of range fits within all of the reasonable recent (=< 12 years maybe) estimates... the variability is just too much and too confusing to keep track of otherwise) 146.199.60.87 (talk) 13:41, 13 August 2019 (UTC)

contradiction

AW197's classification contains two different descriptions: cubewano, detached object. That is impossible. An object cannot be simultaneously detached and a cubewano. Any detached object would have a perihelion beyond the main belt. Serendi^podous 14:26, 11 May 2019 (UTC)

The erroneous detached object classification of 2002 AW₁₉₇ has been removed. This list is quite large, and there may be some errors that I have missed. Nrco0e (talk) 04:43, 12 May 2019 (UTC)

I'm not getting on your back or anything. I'm impressed you took this on at all. The time I spent on it pretty much broke me. Serendi^podous 15:38, 13 May 2019 (UTC)

Surface gravity

Should the Surface gravity section be removed? I don't think it is relevant to the list since the surface gravity of objects are only listed for those with radii over 400 km. Nrco0e (talk) 00:35, 12 June 2019 (UTC)

I'm ambivalent, but some comments: It's not meaningful for the smaller bodies, since the non-spheroidal shapes can lead to varying surface gravities depending where you stand on the equator. This is also applies to larger non-spheroidal bodies, like Haumea, but the smaller ones are much more likely to have that problem. We also don't have the mass for a lot of the small and mid-sized bodies. The numbers get too small to be "interesting". Thus the cut-off here. It's similar to the discontinuing of the volume column, and of the Earth-units for the other columns. The surface gravity is interesting for the larger bodies, as in "how much would I weigh on XXX", which is why it's here in the first place. It's in the tables in List of gravitationally rounded objects of the Solar System, but not sortable there. Tbayboy (talk) 02:34, 12 June 2019 (UTC)

Probably somewhere around the point where you can achieve escape velocity by walking, so even relatively slow moving objects wouldn't be captured into its gravity and pretty much all kicked-up dust would be permanently lost into space, seems a reasonable limit, as the object's hill sphere is likely to be pretty small and not have any significant influence on its neighbourhood or gather much additional material over a sub-million-year timescale (on top of which, exploration by humans, rovers that move at any kind of reasonable pace, or probes that need to orbit the object would become extremely difficult). Not sure what that would be, but maybe 0.1 milli-G? Below which it could be listed as "insignificant", or just not listed at all (the same as mass and density estimates aren't for most smaller, little-studied objects). 146.199.60.87 (talk) 13:38, 13 August 2019 (UTC)

Measurement of HE

We have some conflicting information on the list, in the first block; there's a statement made in its lede that Rhea is the "smallest object for which detailed measurements have been made and found to be in Hydrostatic Equilibrium", and that its size plus that of Iapetus bracket a transition point of about 750km radius (quite where that leaves Oberon is anyone's guess).

But there are many objects on the list smaller than Rhea which seem to be strongly considered in HE (e.g. Makemake, as that was a condition of it being confirmed as a dwarf planet), presumably from being observed, measured and confirmed as such, and the line in the table listing Ceres clearly states that it's in HE. How do we know that? Psychic moon-rays?

Possibly the information has been misstated or poorly explained, but the statement as it stands seems in conflict both with parts of the following list, and assertions made on the individual pages for many midsize minor planets below the size of Rhea/Oberon/Iapetus that they are considered to be in HE from measurements of their size and/or mass plus lightcurves, occlusions, etc. Particularly for Makemake and Ceres given the importance of that confirmation for their classification, but also the "dwarf planet candidate" status of several others (2007 OR10/Gonggong, Quaoar, Orcus, Salacia etc) which are essentially just waiting in a queue for the IAU to get round to confirming them, not to mention the remaining large moons of Saturn and Uranus (and Pluto...).

So which is it ... have they been properly measured and confirmed or not? Either that lede is massively out of date and needs corrected to match the current state of play (for one thing I find it hard to credit Ceres not being sufficiently measured, given that its own article shows multiple extremely detailed photographic and topographic maps of its entire surface, plus analyses of its likely internal structure etc, and we more than likely have gravitational strength maps for it as well - we almost certainly know more about it than we do Rhea), or a good number of dwarf/minor planet & (dwarf) planetary moon article pages will need altering... 80.194.203.132 (talk) 13:28, 1 August 2019 (UTC)

At the time Makemake and Haumea were declared DPs, it was thought that HE for icy bodies happened around 400 km. Since then, it was found that several of Saturn's round moons (notably Iapetus) had shapes incompatible with HE, and that 2002 UX25 has a non-HE-compatible low density. Ceres was since measured and found to be compatible with HE, and Vesta not HE. Going by memory, measurements from Cassini images found Mimas, Enceladus, and Iapetus did not have HE-compatible shapes, and Tethys and Dione were indeterminate (whether their shapes are HE-compatible depends on their unknown internal structures). What was thought to be a fairly clear and simple transition from non-HE to HE turns out to be complicated, and the details aren't known.

Nobody knows if the IAU is confirming DPness anymore (probably including the IAU :-)). They have a process such that sufficiently bright objects are named assuming (but not asserting) they are DPs; no currently known, un-named objects meet the criteria. Haumea and Makemake were named under that process, and called DPs in the IAU press releases, but that was when Marsden was the MPC director. Brown publicly objected to that, and Marsden has since died, so the current MPC director might be gun-shy about such declarations.

There is no easy way to determine HE, no measurement, so don't expect any positive confirmations soon. And yes, the lead is out of date on this, as well as many articles. Although all that has really changed is that the grey zone has gotten much larger; 400 km is still a possible starting size. Tbayboy (talk) 17:52, 1 August 2019 (UTC)

Thanks. Maybe the statements need to just show whether something has been confirmed either in or not in HE and leave it at that without comparisons, though I do notice that Rhea's article now says "second smallest" (...or did it say that originally and I had a massive brainfart?). Interestingly whilst going through further research, it seems that bodies even as large as Haumea now have their HE in question, due to low density suggesting lack of compaction and differentiation, and irregular shapes that might not even be proper Jacobi ellipsoids. So there could be quite a bit of confusion over whether to consider any new object not studied up close by an actual probe as DPs, given that the status of those few already accepted could be in doubt... (then again, I suppose "gravitationally rounded", which IIRC is the exact wording used, might not necessarily be absolutely the same as "in hydrostatic equilibrium")

I wonder what this all means for the potential acceptance of the proposed name for OR10, and whether MS4 might get one, along with the other nine objects currently considered over 600km diameter which would fill in the name gaps all the way down to Gǃkúnǁʼhòmdímà / Ixion / Chaos (the first of which was recently named and therefore was probably assumed to be a DP; after which we can probably leave it given the rapidly increasing number of objects in the less significant smaller size bins; NB assuming RF43 gets bumped up the list due to recent increase in estimated size)? Not to mention names for any of their moons (which even Makemake's doesn't look to be in line for any time soon)...

Incidentally by "bright" do you mean "large", or simply bright (and then, apparent or absolute magnitude)? It does seem to go up sort of exponentially given that larger objects are *usually* (though not always) higher albedo, and vice versa, but there are exceptions, and it also hinges on distance... 146.199.60.87 (talk) 13:28, 13 August 2019 (UTC)

The IAU's naming directive refers to absolute magnitude: if it's 1 or less, the name is confirmed by two committees (forget which) under the assumption that it's a DP (but not necessarily asserting DP). Above H=1, it's named under the usual SSSB procedure. There are no known un-named objects that require this. Actual DPness doesn't matter for naming. For the IAU DP criterion, see Dwarf planet: it's actually "has sufficient mass for its self-gravity to overcome rigid body forces" with HE and "round" as stated consequences of that (otherwise something similar to Methone could be a DP). Tbayboy (talk) 04:10, 14 August 2019 (UTC)

This was talking about HE in the really strict sense, in which Iapetus fails because it is too oblate for its current spin. We mostly moved away from it since because it became clear that nobody is using that level of strictness to classify such bodies (since otherwise Mercury would not be a planet, which it obviously should be). Realistically, though, Iapetus has probably been in HE in the past, and so have all the Cronian moons down to Mimas. When people talk about the round moons, surely Iapetus is included. (No geophysical-definition proponent would exclude Enceladus!)

I guess one might be able to make an argument that Iapetus' equatorial ridge disqualifies it as visibly walnut-shaped. I don't quite buy it since the visibility is dependent on the angle.

However, it has also become clear that the icy moons of Saturn are not a good guide to how TNOs are likely to look. First, they are too icy (Mimas, Tethys, and Iapetus are almost pure ice): Uranian moons are a bit better here, except Miranda. Second, they have a much warmer thermal history and present than TNOs. It turns out that UX25 was just the first warning bell, and that actually a lot of TNOs up to 900-1000 km diameter never got warm enough to self-compress much. At those temperatures, ice is strong and adding rock makes it stronger. They likely have a lot of holes in their structure (think of Hyperion). The largest ones in this scale like Salacia or Varda could have begun to collapse, but only near the core. This is a much higher transition range than anyone had suspected and means that there are likely very, very few DPs, not the hundreds we once thought there were. Gonggong and Quaoar are likely large enough to be DPs (though the uncertainties still leave it open), but even Sedna and Orcus could be justifiably questioned. OTOH they also might be if they got whacked and therefore managed to melt (seems more likely for Orcus than Sedna for obvious reasons). Well, who knows. :) Double sharp (talk) 15:41, 1 October 2021 (UTC)

Can we get the logarithmic size histogram updated?

It maybe only needs minor revisions, but it is still out of date. EG, Chaos is no longer in the top 50, having been displaced by 2010 RF43 (which in fact may need moving up the main list to just under Dysnomia anyway, instead of sitting between Ixion and Chaos, as recent best estimate is more like 695km diameter / 347.5km radius), and 229762 has been renamed to Gǃkúnǁʼhòmdímà, with a new size estimate of 632km/316km. There's probably other value and position adjustments needed too, maybe as far up as Eris and Dysnomia... 146.199.60.87 (talk) 13:19, 13 August 2019 (UTC)

I could update the old non-logarithmic version since it's just text, but the log version is an embedded png that requires image processing chops that I don't have. What do people think? Tbayboy (talk) 04:14, 14 August 2019 (UTC)

When this can be done, would it be possible to add error bars, either brackets or a lighter color at top? That should give readers an idea of how much things could change as we learn more, which bodies are secure and which are guestimates. Currently the graph is misleadingly absolute.

There are also missing largish objects that might should be in the main list. Johnston's Archive estimates from an assumed low albedo, and generally has larger estimates than e.g. Brown, but 1995 SM55, 2015 KH162, 2001 KA77, 2017 FO161 are all listed as r > 300km on JA (the cut-off for the log graph), and there another 15 with r > 250km that we don't have. — kwami (talk) 18:33, 4 October 2019 (UTC)

(55636) 2002 TX 300

Missing this Kuiper belt object in the list. Radius: ~143 km ! — Preceding unsigned comment added by 141.20.50.39 (talk) 19:31, 11 December 2019 (UTC)

Hydrostatic equilibrium of planets

I have seen that in recent updates this article suggest that all the terrestrial planets (Earth,Venus,Mars and mercury) are not in hydrostatic equilibrium. But the defining criteria of planet insist that hydrostatic equilibrium is must to become a planet.This means that they are not planets ,then what are they "asteroids". And despite of this if they remain planets, then asteroid Vesta is also a planet .

       Also this article suggests that Pluto and Ceres are also not confirmed in hydrostatic equilibrium, then how they dwarf planets !?

Conclusion: if Earth, Venus, Mars , Mercury , Pluto and ceres are not in hydrostatic equilibrium then how they are Planets or Dwarf planets ? Then what are they at all? Ayush pushpkar (talk) 04:27, 25 December 2019 (UTC)

Trans-Neptunian moons

Mass,density and shape of many Trans-Neptunian moons expect those of Pluto's ( Dysnomia, Vanth, Hi'iaka, ll'mare, Namaka, weywot, Actaea and moons of Makemake and Gonggong ) needs to be determined more accurately and their sections need data from more resources. Ayush pushpkar (talk) 04:59, 25 December 2019 (UTC)

Hygiea and Interamania

Could really objects that small can be in hydrostatic equilibrium, and thus become dwarf planets, when the larger Vesta and Pallas are not? Ayush pushpkar (talk) 05:01, 25 December 2019 (UTC)

Not implausible. Hygiea and Interamnia are ice-rock, whereas Pallas and Vesta are mostly rock. Ice is weaker than rock, so should gravitationally collapse more easily. BTW, Mimas is smaller and icier than Hygiea, and it surely is round! Double sharp (talk) 15:24, 1 October 2021 (UTC)

Hydrostatic equilibrium

Okay, this is confusing. Recently, there has been a bunch of edits regarding hydrostatic equilibrium in bodies and I think we are taking it way too seriously. This a list of Solar System objects by size after all, there shouldn't be any fussy edits that overcomplicate this list. Nrco0e (talk · contribs) 02:59, 2 January 2020 (UTC)

@Nrco0e: I agree. It's insane to push the view that Earth, Venus, Mars, and Mercury are not in hydrostatic equilibrium (HE), which under the IAU definition, would make them minor planets instead of planets. On the article on the IAU definition of planet, it reads

there is no precise point at which an object can be said to have reached hydrostatic equilibrium. As Soter noted in his article, "how are we to quantify the degree of roundness that distinguishes a planet? Does gravity dominate such a body if its shape deviates from a spheroid by 10 percent or by 1 percent?"

What is the point of going through a list article and pushing a very particular POV that uses a very specific definition of HE? I believe that to do this kind of thing is effectively POV pushing behavior. I'm not sure how the situation should be fixed, though. Perhaps all references to HE should simply be erased, since it reflects a particular POV and doesn't contribute to the article in any way. BirdValiant (talk) 20:01, 10 March 2020 (UTC)

@BirdValiant: So I figured it is best to boldly remove the HE nonsense from the article. Nrco0e (talk · contribs) 22:00, 10 March 2020 (UTC)

@Nrco0e: I support the change. BirdValiant (talk) 22:16, 10 March 2020 (UTC)

There's also a statement in the paragraph preceding the actual list that The Moon isn't in HE, but cites no source to support that claim. This also contradicts the article for Iapetus, which states it's the largest Solar System body not in HE, since the moon is quite a bit larger than that. Would we be clear to go ahead and remove that statement as well?184.186.197.37 (talk) 16:06, 29 July 2020 (UTC)

@184.186.197.37: Better off to remove that claim. Nrco0e (talk · contribs) 16:40, 29 July 2020 (UTC)

dubious tags

The figs for the smaller bodies need to be checked. Often the sig figs of the error bar don't match the measure. When I've checked discrepancies like this, it's generally do to a misreading, where someone messed up a decimal point. So the error bar could be 10x what we indicate here. I've marked those I've noticed with 'dubious' tags rather than checking them all, but this list might be too long too long to maintain effectively. — kwami (talk) 06:23, 8 January 2020 (UTC)

Missing objects

Just curious. I noticed today that 2023 Asaph and 323 Brucia are missing from the list. Is it just that this list is missing a lot of the minor planet bodies, and need editors to add them? Or something else related to scope of the list? N2e (talk) 21:02, 12 July 2020 (UTC)

Reduction of list size

This list has become far too large to navigate comfortably and this page noticably has a lower performance with all those references and images. This page exceeds 300,000 bytes, so I will be removing most, if not all non-notable objects that do not have accurate size estimatess. Nrco0e (talk · contribs) 18:06, 15 July 2020 (UTC)

While I agree the list could be trimmed (I wasn't a fan of it getting this big in the first place) 300k isn't actually that long for a Wikipedia list. Just look at the lists that are longer. Serendi^podous 19:47, 15 July 2020 (UTC)