Talk:Haumea/Archive 3

Archive 1

Archive 2

Archive 3

Unique elongation

The header claims that "Haumea's extreme elongation makes it unique among known" TNOs. However, the article on (20000) Varuna says that Varuna is elongated, too. So Haumea's is not "unique", but just "rare" or "unusual". Except, maybe the claim for uniquity is based upon the uncertainty of the Varuna claim? Even so, I think the "unique" claim is overstated, since it is still plausible for Varuna. Tbayboy (talk) 17:15, 19 July 2010 (UTC)

It would be unique (and extreme) among known dwarf planets and that does basically include TNOs with known diameters. But yes, it is somewhat misleading since a typical mid-sized TNO should be irregular in shape. We could change it to say "among known dwarf planets". I believe the status of Varuna (since Varuna is around 500km in diameter and thus half the size of Haumea) is that it is suspected of being elongated, but unconfirmed. -- Kheider (talk) 17:34, 19 July 2010 (UTC)

See the Varuna page. The IR size measurements are 500 (Spitzer) and ~900 (two others, earlier), but the Spitzer authors had problems and prefer the earlier results, so it's a solid DP candidate. As to elongation, both are assumed elongated because of their apparent spin, neither confirmed. All of which is to say that it's a fine distinction to make here re "known". It definitely should say "dwarf planet" or "plutoid" or "objects in hydrostatic equilibrium", just to exclude potatoes (wasn't a little TNO recently measured by occultation?). I don't see any reason to emphasise the rarity of elongation as compared to other TNOs, though, since it applies to all known HE bodies, including planets and stars! Tbayboy (talk) 18:56, 19 July 2010 (UTC)

2002 TX300 occultation results were just released and 28978 Ixion may have occulted a star last night. -- Kheider (talk) 19:39, 19 July 2010 (UTC)

'Very early' collision for the Haumea family?

The last sentence's conclusion doesn't seem to follow, logically.

"Because it would have taken at least a billion years for the group to have diffused as far as it has, the collision which created the Haumea family is believed to have occurred very early in the Solar System's history."

If the Solar System is ~4.5 billion years old, why does the diffusion requiring 1 billion years require a collision 'very early' in its history? Surely any time on the first 3/4 of of its lifespan would do?

Also, perhaps it would be rephrased so the sentence doesn't start with 'Because'. —Preceding unsigned comment added by 81.156.125.41 (talk) 13:52, 18 August 2010 (UTC)

Crystalline ice covers 75% of Haumea surface

• "Dwarf planet Haumea shines with crystalline ice". Physorg.com. May 12, 2011. Retrieved 2011-05-12.
• Dumas, C.; Carry, B.; Hestroffer, D.; Merlin, F. (2011). "High-contrast observations of (136108) Haumea. A crystalline water-ice multiple system". Astronomy & Astrophysics. 528. Bibcode:2011A&A...528A.105D. doi:10.1051/0004-6361/201015011. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)

Regards, RJH (talk) 21:28, 12 May 2011 (UTC)

Uncertainty in Absolute Magnitude

Why there is such a big uncertainty in the absolute magnitude? --JorisvS (talk) 12:05, 19 August 2011 (UTC)

In the source (JPL), it's similar to that of several other big TNOs I looked at. It just seems to be the accuracy of the current technology. Tbayboy (talk) 14:24, 19 August 2011 (UTC)

Scalene

Why is Haumea a scalene ellipsoid and not an oblate one? --JorisvS (talk) 10:12, 6 December 2011 (UTC)

Rapid spinning. Spin a little and it flattens out, like Saturn. Spin more, and it starts to break apart, stretching out the oblate object into a scalene. There's a paper referenced in (IIRC) a recent Distant EKOs that suggests that many of the TNO multiples are caused by spin-induced fissioning, not huge impacts. Per the paper, the spin can be caused by several smaller (non-catastrophic) impacts. Once it spins fast enough, it stretches into a rugby ball like shape, and material can fly off the tips, forming moons. Tbayboy (talk) 18:08, 6 December 2011 (UTC)

So why would it become scalene when spinning rapidly enough? Something needs to break rotational symmetry for this to happen. Is the little gravity from perturbing bodies sufficient to do this? --JorisvS (talk) 18:54, 6 December 2011 (UTC)

This would usually be before any satellites (the paper's hypothesis is that it is the cause of the satellites), but I would guess any pre-existing satellites could have such an influence. My guess is simply that the final push to "too much spin" is caused by a collision, which itself provides asymmetry in mass and energy. Even without considering that, the body itself would not be perfectly symmetric. Tbayboy (talk) 19:22, 6 December 2011 (UTC)

Instability in the body itself would be enough. No body is perfectly uniform. We could theoretically have an oblate body past the scalene limit, if it were perfectly uniform, just as we can have liquid water below its freezing point, but it would be unstable. — kwami (talk) 19:38, 6 December 2011 (UTC)

Yes, makes sense. Could we add something about this to the article? At which rotation period would a rotating body turn into a scalene ellipsoid? --JorisvS (talk) 19:43, 6 December 2011 (UTC)

I'll try to re-find the paper tonight and put a link here. I'm unsure of the applicability, since it's a new, unchallenged hypothesis, and I'm not sure of competing hypotheses (one big smack? merged contact binary?). No idea on your second question. I think that would depend on a lot of factors. Note that one of the examples I read (somewhere) of oblate-to-scalene transformation is hand-spinning pizza dough, so the concept covers a lot of territory. Tbayboy (talk) 20:13, 6 December 2011 (UTC)

It was easy to find: Rotational fission of Trans-Neptunian Objects. The case of Haumea Tbayboy (talk) 21:49, 6 December 2011 (UTC)

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Surface Area

The surface area is an order of magnitude estimate, but is way off. I get something like 7,700,000 mi^2, but it should be somewhere around 2,500,000 mi^2 especially when considering it's mean radius and place in order of mean radius between Iapetus and Charon, who's know surface areas are 2,586,884.46 mi^2 and 1,768,347.89 mi^2 respectively. Can anyone find a better source? Wally moot (talk) 05:29, 25 March 2013 (UTC)

dubious tag

I've tagged the claim that Haumea and Makemake are DPs as 'dubious' not there because I doubt they are—I don't,—but because the wording is inconsistent with other articles and reflects bias for some sources over other, perfectly good ones (Sheppard, Brown, Tancredi, etc.). I'd be happy with using "is" only for the 3 known DPs, or for the 9 "must be" DPs, but not for a distinction based on H when H is not part of the IAU definition of a DP. (Perhaps some sort of 'bias' tag would be better than 'dubious'? If so, I'll be happy to change it.)

My suggested wording is,

It has been accepted as a dwarf planet for naming purposes by the International Astronomical Union and by most astronomers.

As far as I can tell from all the sources we have, those are the facts: Haumea and Makemake are not actually known to be DPs, unlike Ceres, Pluto, and Eris, which per Tancredi are directly confirmable, and which the most skeptical of our sources, Sheppard, accepts without reservation. The only sourceable (as opposed to OR) distinction between them and the Brown four is that Haumea and Makemake have been accepted as DPs by the IAU and therefore by the great majority of astronomers. (I say OR, because it is not up to us to set a lower mass, size, or precision boundary for DPs as a way of separating Haumea and Makemake from the Brown four.) If my wording does not adequately reflect the sources, then I'm sure someone can come up with better. — kwami (talk) 11:02, 6 January 2012 (UTC)

As for your reference "Plutoid chosen as name for Solar System objects like Pluto", it states it very clearly that these "very bright absmag<1" objects are listed as dwarf planets. It then states they will be removed "If further investigations show that the object is not massive enough". We have no references that Makemake is not massive enough and we KNOW the mass of Haumea. -- Kheider (talk) 13:04, 6 January 2012 (UTC)

Yes, it does state that very clearly, which is why we should reflect it in the lead, and why I'm so puzzled by your continuing refusal to do so.

The essential point is hydrostatic equilibrium. That is what the IAU definition is based on. "Massive enough" means "massive enough to cause HE". The fact that we know the mass of Haumea is not the issue, as the HE limit depends on factors besides mass (such as tensile strength), and it has not been established. Also, we don't know the mass of Makemake (as you just pointed out in the lead), but that makes no difference to IAU naming, which is not based on HE, but on abs. magnitude. The IAU is acknowledging here that just naming a body through DP channels does not make it a DP. Accepting it as a DP does not make it a DP. What makes it a DP is whether it's in HE, and we don't know that, as the IAU itself admits.

Everyone (AFAIK) accepts that Ceres, Pluto, and Eris are in HE, so there is no debate about them being DPs. (The only debate is whether DPs should be considered planets, as Stern maintains, but that's a philosophical difference, not a factual one.) Not everyone accepts that Haumea and Makemake are in HE, so there is debate, and brushing it under the carpet is an embarrassment to WP. Granted, there isn't very much debate: The IAU makes allowances for the possibility, but most sources simply accept them as DPs. However, the IAU did not accept them as DPs because it's been demonstrated that they are DPs, but because they set up a criterion for which committee got to name them. An arbitrary criterion, which had only the most tenuous connection to the definition of a DP. Sheppard reflects this by saying they are "likely" to be DPs, the same wording he uses for Sedna, OR10, Quaoar, and Orcus. That's the issue that we should be honest enough to address up front: not that they "are" DPs, but that they have been accepted as DPs by the IAU and most everyone else. Either that, or we can say that all of Sheppard's list "are" DPs: Neither Sheppard, nor Brown, nor Tancredi draw a line at H < 1. Either way works for me, just as long as we're consistent. — kwami (talk) 14:11, 6 January 2012 (UTC)

You can not live a day without lying. No source says that "Haumea" was accepted for naming purposes". Ruslik_Zero 14:22, 6 January 2012 (UTC)

Are you really so arrogant that you think that anyone who disagrees with you is "lying"? — kwami (talk) 14:46, 6 January 2012 (UTC)

Ruslik, read the IAU release linked to above by Kheider, specifically the paragraph beginning with "In Oslo, members ...". --JorisvS (talk) 14:48, 6 January 2012 (UTC)

I have read it many times. However I have been unable to find where it says anything about Makemake or Haumea. Ruslik_Zero 14:51, 6 January 2012 (UTC)

Please keep YOUR definition of a dwarf planet to the Talk:Dwarf planet page where the consensus is that we list the 5 IAU dwarfs and the rest as merely strong candidates. Any object with an abs mag < 1 will be a dwarf-planet beyond any reasonable doubt because it will be almost impossible for such a body to be less than 800 km in diameter. The data showing Sedna and OR10 as dps is not as solid as the data showing Haumea (bright+known mass) and Makemake (bright+size fairly well measured @ 1400km). -- Kheider (talk) 14:52, 6 January 2012 (UTC)

Is that my definition? Funny, I don't remember draughting it for the IAU. They didn't even give me credit for it!

The IAU has chosen one arbitrary boundary as safe. Brown has chosen another. Sheppard yet another. They disagree with each other. Where sources disagree, it is our responsibility to report on the disagreement. It is irresponsible to cherry-pick references to get the result we favor. And, of course, your opinion on the DP page is not "consensus". — kwami (talk) 15:01, 6 January 2012 (UTC)

The IAU 5 is the logical mid-point between only 3 dwarfs and claiming 9+. All the sources are in basic agreement over the 5 IAU dwarfs. -- Kheider (talk) 15:13, 6 January 2012 (UTC)

That is not true. Sheppard et al. (2011) talk about Haumea and Makemake as 'likely dwarf planets', on a par with Sedna, 2007 OR10, Orcus, and Quaoar. --JorisvS (talk) 15:17, 6 January 2012 (UTC)

(edit conflict) Not logical, just in-between. All of these populations—3, 5, 9, and the others—are reasonable, but all are arbitrary. (Apart from Sheppard's 3, which are the only ones actually demonstrated to be in HE.) If we're to be honest to the scientific literature, which we have an obligation to be, then we need to report the Sheppard 3, the IAU 5, and the Brown 9. — kwami (talk) 15:22, 6 January 2012 (UTC)

Sheppard (2011) page 7 says, "as are the next largest bodies in the outer solar system such as Sedna, 2007 OR10, Orcus and Quaoar." This (IMHO) suggests Sheppard treat these 4 as lesser than the Haumea and Makemake. Obviously they are lesser candidates (Sedna, OR10) or smaller (Orcus, Quaoar) based on what I outlined above: "The data showing Sedna and OR10 as dps is not as solid as the data showing Haumea (bright+known mass) and Makemake (bright+size fairly well measured @ 1400km)." -- Kheider (talk) 15:33, 6 January 2012 (UTC)

But that is OR. You are reading a personal interpretation into his words. What I read into them is that he's listing the 'official' DPs first, because they are official and therefore usually presented separately. What he actually says of all six is that they are "likely", so that's all we can take away from it.

I do agree, of course, that the data isn't as solid for the Brown four. But the point is that, apart from the original three, the data isn't solid for any of them. We're dealing with degrees of solidity, and varying opinions as to where we should draw the line. Sheppard accepts none, the IAU two, Brown six, but these are all opinions, not facts, and we need to report the opinions of experts in the field when they differ.

I also appreciate your account above of the IAU rational, and would be happy to accept s.t. along those lines as superior to my wording of "accepted for naming purposes", which doesn't capture the essence of the IAU decision. — kwami (talk) 15:42, 6 January 2012 (UTC)

(edit conflict)Yet, he considers Makemake and Haumea 'likely DPs', just like Sedna etc., which he contrasts with 'bonafide DPs' Eris, Pluto, and Ceres. --JorisvS (talk) 15:43, 6 January 2012 (UTC)

BTW, Kheider, it's been a long time since I felt we were having a constructive discussion. It's nice. — kwami (talk) 15:49, 6 January 2012 (UTC)

I agree that Sheppard (nor Brown, nor Kevin Heider) are 100% certain that Haumea or Makemake are dps, but to treat them on the same level as Sedna and OR10 (which have undetermined sizes and masses) would be misleading. -- Kheider (talk) 15:53, 6 January 2012 (UTC)

But I've never said we should treat them on the same level! 3 are universally accepted. They "are" DPs by any referenceable standard. 2 are accepted by the IAU for the reasons you gave above. Due to the importance of the IAU, they are generally accepted as DPs, and of course the circumstantial evidence is stronger than for the rest. 4 more are accepted by Sheppard and Brown as being on par with these two. Sheppard uses the word "likely", and Brown "virtually certain" and "must be". Tancredi & Favre would add a few more, but we haven't heard from them for a few years. I'm not asking that we follow Brown or Sheppard instead of the IAU, just that we not follow the IAU to the exclusion of Brown & Sheppard. When we describe an object as a DP or likely DP, that initial claim should reflect the literature. The exact wording isn't so important, as long as we do not privilege our favoured source over the others. — kwami (talk) 16:08, 6 January 2012 (UTC)

"4 more are accepted by Sheppard and Brown as being on par with the these two." (Haumea+Makemake) This is the part I feel is synthesis. -- Kheider (talk) 16:17, 6 January 2012 (UTC)

Where's the synthesis? They use the same words to describe the likelihood of them being DPs. That's what we have to go on. For Sheppard, 3 are "bonafide", 6 are "likely". For Brown, all nine "must be" DPs. In Tancredi & Favre, all but OR10 (which is too recent) are marked "yes" under the DP column. I don't see any synth there. Their criteria merely differ from the IAU's. — kwami (talk) 16:29, 6 January 2012 (UTC)

Neither Sheppard nor Brown specifically state that "Sedna, 2007 OR10, Orcus, and Quaoar" are just as likely to be dps as are Haumea and Makemake. -- Kheider (talk) 16:46, 6 January 2012 (UTC)

And I don't expect that they do think that. (Also, the IAU doesn't specifically state that H and M are just as likely to be DPs as C, Pl, & E.) But that's irrelevant, because no-one claims they do, and nothing depends on them doing so. The point is that different sources have different criteria for which bodies they accept as DPs. Sheppard accepts 3. The IAU accepts 5. Brown accepts 9. Tancredi accepts 12. You've chosen one number out of several, and defended it essentially with an argument from authority. That's legit when defining what a DP is, because no-one disputes the IAU definition or their role in establishing it, but scientific claims cannot be established that way. Doing so is profoundly unscientific. — kwami (talk) 17:26, 6 January 2012 (UTC)

In the Haumea and Makemake articles, NONE of the sources (EDIT: currently in use in the article) suggest that they (EDIT: Haumea and Makemake) are not (EDIT: likely to be) dps. The whole Talk:Dwarf planet issue about inserting table(s) listing many poorly known candidates (objects with unknown masses and sizes likely less than 1400km) is subject for that article, not Haumea or Makemake. -- Kheider (talk)

That makes no sense at all. We can only say things that are supported by the sources already in the article? So if Sedna were declared a DP by the IAU tomorrow, we wouldn't be able to mention that in the Sedna article, because none of the existing sources say it?

Kheider, we follow sources. That's all this has ever been about. After a few hopeful hours of reasonable discussion, you would appear to be reverting to "I don't like it". — kwami (talk) 18:38, 6 January 2012 (UTC)

If we had an IAU reference stating that the IAU declared Sedna a dp, we would change the Sedna article to reflect an increased consensus. Hopefully the IAU would give an explanation (since as of today we do not know the mass or size of Sedna.) Wikipedia is not a crystal ball and I do not think we should clutter the dwarf planet article with needless tables about the lesser candidates that do not add to the understanding of the topic. We already have two sections in the dwarf planet article called "Official and "nearly certain" dwarf planets and Additional candidates -- Kheider (talk) 18:54, 6 January 2012 (UTC)

What are you talking about? No-one is advocating that either! Honestly, I don't know where you get these ideas.

At DP, I'm asking that we consolidate the tables, because the current division is SYNTH, and the headers contradict our sources. You said you would find it acceptable if we had one table coded by who accepted the body as a DP. No-one is saying that we should add more tables.

If we could add more IAU sources to the Sedna article, then why would you object to adding sources to this article? I don't get it. If we have a RS that Haumea is or maybe is or maybe is not a DP, why shouldn't we be able to add it? — kwami (talk) 19:01, 6 January 2012 (UTC)

Ok, back to Haumea/Makemake, show me one source that states Haumea/Makemake are NOT likely to be dps. We already know the IAU does not currently list Sedna or OR10 as a dps. -- Kheider (talk) 19:13, 6 January 2012 (UTC)

Again, where are you coming from? No-one has ever said that Haumea or Makemake are not likely to be DPs. And of course the IAU does not list Sedna. No-one ever said that either. — kwami (talk) 19:32, 6 January 2012 (UTC)

You added the dubious tag to this article to help restart the never-ending Talk:Dwarf planet debate. This all started in August 2011 when you decided to list Sedna, OR10, Orcus, and Quaoar as dwarf planets. Your POV-pushing pushed a lot of buttons when you should have been busier getting a consensus on the talk page. I am still not convinced a combined IAU dp+candidates table adds anything to the article, or if it just makes it more difficult for the average reader. Some of your early synthesis was that even Eris was not accepted as a dp. -- Kheider (talk) 19:47, 6 January 2012 (UTC)-- Kheider (talk) 19:47, 6 January 2012 (UTC)

Again, you're misrepresenting me. I never said that Eris was not a DP, and certainly don't say that in the link you just gave.

At the time of that edit, we had been discussing sources which said that Ceres and Pluto are known to be in HE through direct measurement, and that Eris is assumed to be in HE because it is more massive than Pluto. With the sources we're now discussing, however, there is no such distinction: Tancredi says that all three are known through direct measurement, and Sheppard says that all three are "bona fide". That was new to me, but all I'm asking is that we respect our sources, and I'm happy to accept all three as certain if that's what our sources say.

I chose the 'dubious' tag because it was the best in-line tag I knew of. A 'POV' tag would have marked the entire article, and I didn't want to do that. I did offer to switch the tag if s.o. knew of a more appropriate one.

As for POV-pushing, the POV I'm pushing is that of the sources. We should reflect all of them, not just one which WP elevates above the rest, as if we were some sort of scientific arbiter.

And as for pushing buttons, are we really going to purposefully not do a good job on the article just because we don't like the attitude of another editor? Isn't that just being WP:pointy? — kwami (talk) 20:06, 6 January 2012 (UTC)

My objection to the lead as it stands now: in the beginning of the first paragraph, we state that it "is" a DP. At the end, we report that a RS says it is "likely" to be a DP. That is logically inconsistent. — kwami (talk) 10:51, 7 January 2012 (UTC)

• My response copied from the RSN discussion,

"If there is a dispute between the IAU and other experts in the field, then you cannot say de facto that anything is something. You have you say that the IAU considers this to be a DP and these other experts consider it to likely be a DP. An short explanation of the different standards that these experts are using may also be required for clarification in the article. But if there is a dispute between experts in the field (and the IAU count as experts, but experts alone and shouldn't be held as definitive on the subject. Our readers must place their own emphasis on which opinion holds better weight, we as editors may not), then you must adequately show both sides of the dispute without being biased toward one side or the other." Silverseren^C 11:07, 7 January 2012 (UTC)

This is an artificially manufactured controversy. The volume of literature where Haumea is ambiguously identified as a dwarf planet significantly exceed anything that Kwamikagami has been able to did up so far. You can see yourself. Even in the Sheppard's article cited above "Haumea" is said to be "likely" in just one throw-away sentence with unclear meaning. Scott Sheppard has never disputed that Haumea is a dwarf planet. For instance, in this article, where he is a coauthor, Haumea is called a dwarf planet without any qualification. So, in even in the worst case the position of Scott Sheppard is unclear. So, summarizing: this is a non-existent controversy, which User:Kwamikagami tries to create by selectively citing some papers out of context. Ruslik_Zero 13:56, 7 January 2012 (UTC)

The point, of course, is that Sheppard accepts the Brown 4 as "likely" as well. There is clearly a dispute among RS's, and no amount of sophistry or accusations of "lying" will change that. — kwami (talk) 02:25, 8 January 2012 (UTC)

It is only your speculations. Ruslik_Zero 08:26, 8 January 2012 (UTC)

We have known since their discoveries that Sedna, OR10, Orcus, and Quaoar could be "mini-planets" (The term dwarf planet was not really in use back when Quaoar was discovered in 2002). Sheppard is saying nothing new. We have never claimed that they are not "strong dwarf planet candidates". The scientific consensus is that there are 5 dwarf planets with many strong candidates that are either small or have poorly known characteristics. The Sheppard reference is used in all relevant articles. -- Kheider (talk) 13:27, 8 January 2012 (UTC)

You have a funny definition of consensus. When major figures in the field disagree, it's not "consensus". "Consensus" means that they agree. Brown does not agree. Sheppard does not agree. Tancredi & Favre do not agree. Barucci does not agree. Malhotra does not agree. Rabinowitz, Schaefer, and Tourtellotte do not agree. None of these researchers cut off the population of DPs at the IAU's five. Therefore the IAU five is not consensus. Now, if all accepted the IAU five plus a varying degree of others, I would agree that the IAU five would be the minimum. However, Sheppard distinguishes between the original three and the rest of the Brown nine. Either Sheppard is a source that all nine are DPs (meaning that we would have to read "likely" to mean "is", which IMO would be OR), or Sheppard is a source that Haumea and Makemake are just "likely", would means that we do not have consensus that they "are". — kwami (talk) 23:53, 8 January 2012 (UTC)

Find me a statement from Sheppard where he specifically states that he doubts that Makemake and/or Haumea are dwarf planets. In the mean time quit speculating so much about a one sentence statement. -- Kheider (talk) 01:50, 9 January 2012 (UTC)

You're confusing things. Sheppard doubts the certainty with which we can say that these are DPs. He obviously doesn't believe it likely that these are not DPs, otherwise he would not call them "likely DPs". --JorisvS (talk) 10:22, 9 January 2012 (UTC)

No, I am not confusing things. All of the evidence makes Makemake and Haumea better dwarf planets than the smaller and less known bodies Sedna, OR10, Orcus, and Quaoar. This is KNOWN and is also what Sheppard clearly means. Texts should be written for everyday readers, not for academics. Kwami has been using this disruptive argument to try upgrading the status of the smaller 4 candidates. Even NASA and the ESA do not list the smaller 4 as dps. -- Kheider (talk) 14:17, 9 January 2012 (UTC)

I'm not trying to upgrade them. Hasn't that sunk in yet? I'm fine with the wording as it currently is in their leads, because it FOLLOWS THE SOURCES.

Better candidates? Yes, Hamuea and Makemake are better candidates. But not certain per our sources, and your attempts to force that reading are OR. As to what Sheppard "clearly" means, that again is OR. What I hear him mean is what he says: that Haumea, Makemake, Sedna, OR10, Orcus, and Quaoar are likely DPs. — kwami (talk) 14:58, 9 January 2012 (UTC)

(Semi-sarcasm, but let's get to the point.) Should we add this disclaimer to the article: "Haumea may not be a dwarf planet because nothing is ever known with 100% certainty. Only God knows what is and is not a dp. Humans claiming they known anything with an absoluteness make God laugh." Another version might be: "Since science is always evolving and learning new things and seldom knows anything with 100% certainty, not all astronomers are 100% certain Haemea is a dwarf planet." WHAT SPECIFICALLY IS WRONG WITH THE STATEMENTS CURRENTLY IN THIS ARTICLE? -- Kheider (talk) 14:22, 9 January 2012 (UTC)

I am puzzled as to why you are unable or unwilling to understand this basic point. Obviously we can't be certain about any of them, including Pluto. But that's not the point. WE FOLLOW SOURCES. I must have said this quite literally a hundred times, yet it seems that those words are still difficult. We have no source that suggests Pluto may not be a DP, so we don't say it. We do have a RS that Haumea may not be, so we do need to say that. It couldn't be simpler. Now, everyone agrees that Haumea is at least "likely" to be a DP, if not "virtually certain" or "must be" a DP, or even just "is" a DP, so we should reflect that degree of certainty. But while everyone just says that Pluto "is" a DP, and we use the same wording, it is inappropriate to use that wording for Haumea when our sources vary. If you want to pretend that Sheppard says that Haumea "is" a DP, then we'd have to do the same with the Brown 4, so it's your argument that would require that they be "upgraded". Personally, I think that your argument is OR, but I do expect us to follow the sources.

We have four categories of objects that people have said are DPs:

• Ceres, Pluto, Eris: every says they are
• Haumea, Makemake: IAU accepts, most say they are, Sheppard says "likely"
• Sedna, OR10, Orcus, Quaoar: Brown et al. say they are, Sheppard says "likely"
• a few more: Tancredi says they are, Brown says "likely".

To lump these together in a way that follows one source but not another violates NPOV. I'm happy with the way the current leads follow sources for all of these but Haumea & Makemake. — kwami (talk) 14:58, 9 January 2012 (UTC)

To speculate so much about what Sheppard meant in just one sentence also violates NPOV and Synthesis. At no point does Sheppard specifically claim that Makemake and/or Haumea are not better candidates than the lesser 4. You read the sentence one way, I read it another. You know that Makemake and Haumea are much better defined bodies. I think I will now exit this conversation since I see no further need to revert the article. -- Kheider (talk) 15:11, 9 January 2012 (UTC)

I presume that Sheppard does think that Haumea & Makemake are better candidates, but (beside that being OR) the point is that they're CANDIDATES. He doesn't accept them as "bona fide". We should therefore reflect Sheppard, and what you yourself have just said, in the lead. As for them being better candidates, we can say that too: We can source it with the IAU, and my proposed wording would present them as better candidates.

Your reasoning is like arguing that we should say there "is" life on both the Earth and Mars because there is a better chance of life on Mars than on the Moon. — kwami (talk) 15:18, 9 January 2012 (UTC)

Kwami, you said above, "Obviously we can't be certain about any of them, including Pluto." Everything is only to the best of our knowledge and references. NASA calls Makemake and Haumea a dp. Case closed. -- Kheider (talk) 15:26, 9 January 2012 (UTC)

Huh, has NASA now suddenly become the arbiter of what gets to be called a DP? --JorisvS (talk) 16:43, 9 January 2012 (UTC)

The case may be closed for you, but it violates our NPOV policy. We don't get to cherry-pick sources. — kwami (talk) 17:20, 9 January 2012 (UTC)

But it is you who are cherry-picking sources. You are ignored this article and many others. Ruslik_Zero 17:50, 9 January 2012 (UTC)

Thank you for an intelligent and polite response. I'd given up reading them, and I just saw this one by chance.

I don't see how we're ignoring that. "Accepted by the IAU and by most astronomers" covers it pretty well, I'd say. An article of which Sheppard is the 4th-named author speaks of the "dwarf planet Haumea". An article of which he's the first-named authors says Haumea is "likely" to be a DP. I expect that Sheppard pretty much assumes it's DP, and so would not object to putting his name on a paper which calls it a DP, but he evidently does not think the evidence provides the level of certainty that we have for Eris or Pluto, or he wouldn't have distinguished it from "bona fide" DPs (as in, there's a bunch of DPs, bona fide and likely, and Haumea falls in the latter camp). I only expect our lead to reflect that, and I think our readers will understand the situation of one RS saying "likely" while the rest say "is". But currently we just say it "is" as if there were no question. — kwami (talk) 05:39, 11 January 2012 (UTC)

I do not think that we should make conclusions from such nuances like "as a 4th named author he says DP and as a 1st named author he says likely DP". Haumea is practically everywhere mentioned among dwarf planets. We should also accept it, unless somebody publishes a serious study questioning this status and giving reasons for such doubts. Is there any recent text, where Sheppard would expressively say something like "I believe that Haumea might not be a dwarf planet, because... "? Or "Results from our recent study suggest that Haumea does not possess some dwarf planet characteristics as they were defined by the IAU"? I do not know any. Everything else is just a speculation. Jan.Kamenicek (talk) 08:32, 11 January 2012 (UTC)

Yes, I'm speculating why the sources say what they do. But that doesn't matter, because we follow what they say, not what you or I think about what they say. Your objection would be valid if I wanted to say that "some astronomers think Haumea is not a dwarf planet". But I don't want to say that. I want to reflect what Sheppard said, which is that we are not sure that it is a dwarf planet. Not being sure that something "is" is not the same as thinking it "is not"; we don't need a source saying the latter to support the former. In his paper, Sheppard said that Pluto is "bona fide" while Haumea is "likely". Regardless of why he said that, that's what a RS says. Therefore we should reflect it. We shouldn't give it undue weight, because, as you say, most astronomers accept it as a DP. We should just say that the IAU and most astronomers accept it as a DP rather than waving away a RS (and a well-respected astronomer) by saying it simply "is". — kwami (talk) 08:59, 11 January 2012 (UTC)

All that one sentence says is that Hauema is "likely" a dp. As you admitted, writing anything else is speculation. -- Kheider (talk) 11:07, 11 January 2012 (UTC)

Yes, "likely". Since you admit that, and even imply that it would be acceptable, why do you oppose saying as much in the actual article? — kwami (talk) 11:28, 11 January 2012 (UTC)

The Wikipedia article says what the reference does: "Sheppard et al. (2011) consider it a "likely" dwarf planet." The reference does NOT go into any more detail, and please do not speculate as to what Sheppard meant. -- Kheider (talk) 11:43, 11 January 2012 (UTC)

I'm not speculating on what he meant, I'm reflecting what he said. Currently, we say it "is" a DP, and then we say it is "likely" a DP. Those two statements conflict. Surely you can see that "likely" doesn't mean "is"? Do I really have to point that out again? If you want to say the IAU and most everyone else says "is", but a few say "likely", that would reflect out sources. But simply saying it "is" violates NPOV. — kwami (talk) 11:47, 11 January 2012 (UTC)

99% of the scientific literature is that Haumea is a dp, we do NOT need to clutter the lead with needless statements that will not benefit the average reader. -- Kheider (talk) 11:59, 11 January 2012 (UTC)

Most of the lit repeats the IAU, which is why we mention the IAU by name. But we have significant researchers who differ. This isn't some fringe theory. And you leave the problem that we contradict ourselves, which is ridiculous in a FA. — kwami (talk) 12:08, 11 January 2012 (UTC)

You like to speculate about one sentence that you might be taking out of context. What would be ridiculous would be to speculate about one sentence from one source in a featured article. -- Kheider (talk) 12:15, 11 January 2012 (UTC)

Congratulations. You would make a good lawyer. Ruslik_Zero 11:12, 11 January 2012 (UTC)

One word in one source is not notable enough. He might have changed his opinion many times since, but the single word will stay in that text forever. Because it seems Kwami has not noticed, I am repeating my questions I have written above: Is there any recent text, where Sheppard would expressively say something like "I believe that Haumea might not be a dwarf planet, because... "? Or "Results from our recent study suggest that Haumea does not possess some dwarf planet characteristics as they were defined by the IAU"? Unless the answer is Yes, we should simply consider Haumea a dwarf planet. Jan.Kamenicek (talk) 14:13, 11 January 2012 (UTC)

We don't need a source that says it's "likely to not be" to support a claim that it's "likely to be". Once again, you're confusing "is" with "is not". Unless you have evidence that Sheppard et al. have changed their minds, all we can go on is what they said. See WP:Crystal Ball. What they said is clear enough: it's "likely to be" a dwarf planet, the same qualifier they gave Orcus and Sedna, and clearly juxtaposed against Eris and Pluto.

Per WP:WEIGHT we should count it as one source, but it's still a relevant RS. — kwami (talk) 14:46, 11 January 2012 (UTC)

Kwami, your writing style seems to speculate that Shepppard's "one sentence in one reference" did not intend to place Eris (page 2), Makemake and Haumea on a higher pedestal than the "next largest" four (Page 7: Sedna, OR10, Orcus, Quaoar). You need a better reference to reliably make such speculation. This is Wikipedia, not youtube. -- Kheider (talk) 15:08, 11 January 2012 (UTC)

Elongated or flattened

Three times the article says elongated, implying it is a prolate ellipsoid. Wouldn't it be better to say flattened or distorted since the rapid rotation would tend to form an oblate ellipsoid ? - Rod57 (talk) 02:40, 8 April 2013 (UTC)

Both: It's a scalene (a.k.a. tri-axial) ellipsoid (see the diagram in this article, or the diagram in the ellipsoid article). Take a nice, regular oblate ellipsoid (like Saturn) then stretch it along an equitorial axis. It's like placing a rugby ball on the ground, then giving one end a push so that is spins flat on the ground. Tbayboy (talk) 03:59, 8 April 2013 (UTC)