Talk:Pluto/Archive 7

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[edit] The mass vs. volume vs. density do not seem to add up.

Good catch Nebular and Art. I was using 2306 on my own papers, I must have read it someplace in the later results on impact of Charon to the old estimates. Anyway, I did some extra checking against data on NASA's planetary fact sheet for Pluto. I still noticed some differences -- mainly in trying to resolve the density value. (www.spds.nasa.gov/planetary/factsheet/plutofact.html)

Mass 1.305x10(power 22) does not match NASA's Pluto Fact Sheet (indicating 1.25 x 10(power 22), but maybe the Wikipedia Page has more up-to-date data? The funny thing is that both NASA (with the different value) and Wikipedia, indicate their masses equal 0.0021 earth masses. NASA = 0.00209 (.0021); Wikipedia = 0.00218 (which is really .0022). Was there a typo somewhere?
Wikipedia's Volume of 7.15 x 10(power 9) matches NASA (which is, correct, 0.0066 earth volumes). The surface area on the Wikipedia page (1.795 x 10(power 7) agrees with the mean radius of 1195 km. The former radius listed (1153) resulted in an "off" surface area of 1.67 x 10(power 7). So, I think the correction to the 1195 radius is in greater agreeement with the other data on the page.
Wikipedia's Density shows 2.03. NASA's shows 1.75 (my calcs, using the NASA figures, come up with 1.748 -- which is close enough). Using the Wikipedia Pluto values for radius, mass, and volume, however, result in a density of 1.825 (which is not close to the 2.03 value).
To get a 2.03 density, but in keeping the radius at 1195 km, we would have to up the mass to about 1.45 x 10(power 22) -- but Charon, Nix, and Hydra might object <grin>.

So maybe we need to update something? Do we need to change the mass to 1.25? Or, if the source data used for the Wikipeidoa Pluto page is more current than NASA's Pluto Plant Fact sheet pages, then one of the values (mass, volume, or density) is incorrect. Tesseract501 8 March 2007

I recommend changing the values to ones that can be verified to come from an authoritative source. If someone wishes to provide more up to date data, it is their responsibility to indicate their source (and the fact that they did not is why we're in this mess). —RP88 02:27, 8 March 2007 (UTC)

In fact, checking around I find that JPL's physical data for Pluto disagrees with the NASA data (although JPL sources their facts to references dated 1992 and 1996 and we've learned more about the Pluto/Charon system since then). —RP88 02:38, 8 March 2007 (UTC)

[edit] Page Protection?

Due to the number of vandals i'm wondering whether we should get this page protected from editing by non-wikipedians ?-- Nbound 10:13, 13 September 2006 (UTC)

The number of reverts that are needed is certainly getting tiresome. I think protecting the page for a month or so, until most of the public fuzz around Pluto has disappeared, might be a good idea. Kris 10:56, 13 September 2006 (UTC)

I've added the page for consideration of protection, to a semi-protected level. (no anonyomous users, and no users less than 4 days old) -- Nbound 11:45, 13 September 2006 (UTC)

Since it's protected, someone with access should make this change: "The craft will benefit from a gravity assist from Jupiter" -> "The craft made use of a gravity assist from Jupiter" (Ask me about signing my posts!) —The preceding unsigned comment was added by 72.192.204.137 (talk) 08:47, 7 March 2007 (UTC).

Done. —RP88 08:59, 7 March 2007 (UTC)

[edit] Name and the style guide

I see there's been a lot of dispute about the appropriate name of the article. I'm astounded that (as far as I can tell) nobody looked at the Wikipedia guidelines for article naming:

Generally, article naming should prefer to what the majority of English speakers would most easily recognize, with a reasonable minimum of ambiguity, while at the same time making linking to those articles easy and second nature.

This pretty clearly supports the use of the unmodified "Pluto" as the article name (or maybe "Pluto (astronomical body)" for disambiguation and NPOV). I don't see anything else in the guidelines to indicate that the other version is preferred. The official name of the 42nd President of the United States was William Jefferson Clinton, but the article is Bill Clinton nonetheless, because that's how he's commonly known.

We have these guidelines for a reason. Use them! Elliotreed 07:56, 7 March 2007 (UTC)

I agree with some of what you write, but not all. I agree that the text of the Pluto page should reference the whole historical reasons behind why Pluto was called a planet to begin with (as was Ceres). I agree that the text of the page should indicated that many people in society and even in the scientific community believe that Pluto is a planet. But, we can't lose sight of the fact that what a "Planet" is defined as is really a subjective matter of opinion. Because of that, see my request, below. By the way, I interpret the guidelines differently: I believe the intent it to communicate with a REASONABLE MINIMUM OF AMBIGUITY. Using colloquialisms lends itself to ambiguity (for example, how several pages incorrectly use the term "civil disobedience" to describe almost all forms of prtests that happen today (although "civil disobedience" is a very specific form of protest). E.g., the anti-Globalization page, etc. Keeping the definition of "Planet" could lead to ambiguity. At the very least, it would lead scholars to doubt how up-to-date the page might be. Like it or not, now that the IAU has made the change to the categorites, usng "Planet" to classify Pluto could now be ambigous, if only because there has never been a clear definition of Planet except to say it was the nine we knew of. Ceres used to be called a planet, but was bumped because we started to realize there were too many objects out there. Now that the IAU has made their own definition of Planet, an uninformed reader could assume that Pluto falls under the IAU definiton (which it does not). Someone decided to create a sub-classification of asteroids. Was that a good thing? That is open to berate. Same situation here, with Pluto. I am not saying that Pluto is not considered a Planet by some (and always will be). Nevertheless, if we want people to use Wikipedia for research data, we should not go with calling things by a "curve" scale. I personally use the term Planetoid instead of Asteroid, TNO, Dwarf Planet, Comet, etc. (because all such subcategories are as subjective and arbitrary too). Regardless, to keep AMBIGUITY to a minimum, we have to use an agreed-upon convention -- at least on the tile pages and search engines. As far as cal ling the President Clinton page, "Bill Clinton" -- If the page is just for fun, then Bill Clinton is OK. If the page is meant to be a scholarly, historical, or biographical work, however, it should be called "William Jefferson Clinton" with a reference to the use of "Bill Clinton" in the text.

[edit] Request to Relocate the Comments about the Pluto Naming Debate

May we move the whole discussion about whether Pluto should be called a Planet, Dwarf Planet, Planetiod, or a Yellow Dog? I am not saying that the debate is unwarranted. In fact, I think it is a good topic for discussion. I am requesting, however, that such discussion be moved to a new page (something specific to the "Naming of Pluto" instead of keeping it on the Pluto page itself. Here is my request ...

Since the root (and stem) of the issue are subjective (on the part of both society and the scientific community) -- this debate could continue until the cows come home. There will always be opposing views on the topic. The whole issue behind calling something a planet becomes ambiguous and subjective once we try to differentiate between the many things that orbit the sun. Granted, the IAU could have handled the P.R. better, and the Dwarf Planet classification will probably result in more problems down the road (e.g., "Santa" and Varuna are most likely elongated spheriods, so will they be excluded from the new Dwarf Planet definition -- even though they are larger than Ceres)?. Regardless, the IAU should have made it clear that they are not trying to claim sole rights to defining the term "Planet". Such a term has, and probably always will be, under the "ownership" of the general public (i.e, everyone has dibs). The IAU focus should be to aid the scientific community in general categorization (as do the new categories). Without such, any attempts at precise communication become difficult -- and precision is necessary for science, but not necessary for our societal connection to individual solar-system objects).
Keep the title page references and the various solar-system body listings in agreement with the IAU. Otherwise, those of us who try to use the pages for technical or scholarly work will have to start going elsewhere to gather our data.
Keep the textual references as to the history of Pluto as being called a planet (and why). Keep the textual references on the page regarding how the Planet association is still kept by many in society and by several scientists as well.
Move all the talk pages about the naming debate to a new page (something titled "What is a Planet" or the "Pluto Naming Debate" or something like that. The same thing already holds true for other debates, such as, should humans be called primates or should a virus be called an organism, etc. Nevertheless, keep the debate to a minimum on the actual Pluto page. It is filling up the talk pages so much, those of us who go to the page to gather actual physical and orbital and astronomical data have to go to the archived pages to check feedback. Tesseract501 7 March 2007

[edit] Inclination and Obliquity

I can not reconcile three items on the Pluto page.

Regarding the Obliquity of Pluto. The Pluto page indicates 119.59º for Pluto's Obliquity. Other technical sources (NASA and others) indicate values closer to 122.5º. Why the difference? Is there a way to have the latest best estimate on this page? If not, will someone at least reference why the 119 value was chosen over the 122 value?
In addition, I am having a difficult time in resolving the Axial Tilt values on the Physical Characteristics (bottom of table) against the Orbital Information section (top of the same table). The Inclination, under the Orbital section, indicates 17.1417º (Pluto's orbital plane to the Earth's ecliptic (orbital plane). Here are the confusing items:

Other wikipedia pages (Earth page) indicate that the Earth's Ecliptic (orbital plane) is 7.25º inclined from the Sun's equator.

The Pluto page indicates that Pluto's orbital plane (inclination) is 11.88º from the Sun's equator and 17.1417º from the Earth's ecliptic (orbital plane).

How does this add up? If Pluto's orbit is 11.88 from the Sun's equator, and the Earth's is 7.25, That's a difference of 4.63º (not 17.1417º). Am I just being obtuse as to how one goes about configuring the data? How did the Pluto page come up with 17.1417 value? Granted, it is probably correct -- several alternative source documents (NASA's fact sheets, etc.) indicate that Pluto's orbital plane is 17.16º to the Earth's ecliptic. This is CLOSE (but not exactly) to the 17.1417 value on the Pluto page. So - that leaves me with the following possible explanations:

(A) I am just not getting it?

(B) The 11.88 "Pluto's-orbit- to-Sun's-equator value is incorrect, or

Along those same lines, I have a question about another Pluto item. How does one reconcile the 122.78º value (Pluto's axis to the Earth's ecliptic plane)? Taking the values referenced above, I can't seem to resolve that number. Tesseract501 7 March 2007

Remember that these things happen in 3D, so simply adding or subtracting angles will not work. (Imagine two planes, all you know about each is that they are 45° to the horizontal. The angle between them many be anything between 0° and 90° according to how close the horizontal direction of their slopes are). If |Sun-Earth| is 7° and |Sun-Pluto| is 12°, then |Earth-Pluto| may be anything between 5° and 19°, roughly, limited only by the spherical triangle inequality: $\sin(a/2)+\sin(b/2)\geq\sin(c/2)$ . –Henning Makholm 00:00, 8 March 2007 (UTC)

Thanks MH, but my question is about how the author came up with the inclination and obliquity values (which are 2D values, not 3D values). It is not so much about angular mathematics, unless you can show me how a given formula comes up with the 112.78º value. The info doesn't seem to match the astonomical data that I have from other sources (NASA, etc.). Regarding the 3D issue, astronomers use the right ascension and declination of the "north" pole, the major axis, the arguement of periapsis, the longitude of ascending node, the mean anomaly, etc., to define the orbit in 3D. My understanding is that Inclination and Obliquity values, in and of themselves, are 2D. If you know how to arrive at the value of 112.78º value, and can detail this, it would be super-duper. Thanks. Tesseract501 00:30, 8 March 2007 (UTC)

[edit] Pluto Planet Day

Can Pluto be declared a planet by a memorial of the state of New Mexico? What does this mean? Should it be mentioned in the article? --128.176.236.34 21:16, 10 March 2007 (UTC)

State legislatures in the US have in the past declared all sorts of odd things regarding the sciences, but they hold no weight in the scientific community whatsoever. At most it might warrant a line in the "Impact of the IAU decision" section, IMO. Bryan Derksen 21:37, 10 March 2007 (UTC)

Note also that it is a memorial, not a resolution. Unlike a resolution, a memorial just expresses an opinion, or urges a certain action, and as such does not have the effect of law. —RP88 05:22, 11 March 2007 (UTC)

[edit] Good article review

Hi there, I am reviewing Pluto for Good article status. It may take 24-48 hours, depending.

I was wondering, is the previous GA review available, I would like to read it over before I dive in. Please respond promptly. Thanks. IvoShandor 05:35, 11 March 2007 (UTC)

I am assuming this is it. It was failed after being on hold? Is that correct? IvoShandor 05:39, 11 March 2007 (UTC)

Anyone want to answer, or should I just fail it. It's not a hard question, I just want to know if what I found is what I am looking for. Message left on nominator's talk page as well. IvoShandor 23:42, 11 March 2007 (UTC)

Based on the article history, yes. That's the one. --Bobblehead 00:08, 12 March 2007 (UTC)

Thank you, review will be posted by tomorrow. : )IvoShandor 00:23, 12 March 2007 (UTC)

[edit] Image copyright problems

I am having a problem with this image. (Image:Pluto structure ESO.gif) I read the ESO copyright page referenced on this Image file's page, and it notes that there are exceptions to the copyright policy. The text of the ESO Copyright page reads: "Reproduction is authorised, provided the source is acknowledged, save where otherwise stated. Where prior permission must be obtained for the reproduction or use of textual and multimedia information (sound, images, software, etc.), such permission shall cancel the above-mentioned general permission and shall clearly indicate any restrictions on use".

Which per the citations on the report that this image was taken from, would disqualify this image for no copyright, as the images credits are to sources which appear to be copyrighted. Though I am not sure who "Kristina" is. This will have to be resolved before the GA nomination can go ahead I am placing the nomination on hold, which I rarely do, but I feel the problem can be addressed quickly, if it isn't the article will, of course, have to be failed. IvoShandor 06:16, 12 March 2007 (UTC)

I don't think you are right. There is no exception from the general policy stated on the citations page for the report. Giving the source is something completely independent. It's possible that ESA has messed up, but as far as we can tell, this image is usable. However, given that the image is simple, but not very good, we can just ask someone at Wikipedia:Requested pictures to redraw something like this. --Stephan Schulz 23:37, 12 March 2007 (UTC)

In fact, I have just made this request... --Stephan Schulz 23:43, 12 March 2007 (UTC)

I found this image on the NASA site. The only thing possibly questionable about it is that it is courtesy of the Lunar and Planetary Institute which is funded by NASA. That generally means the product is owned by the government as well. --Bobblehead 00:00, 13 March 2007 (UTC)

I just made an SVG replacement for the image. It's at Image:Pluto-cutaway.svg. I'm no graphic artist, so let me know what you think. —RP88 01:46, 13 March 2007 (UTC)

Thanks! I like it. Is that a standard texture on the surface or where did you get it? --Stephan Schulz 08:17, 13 March 2007 (UTC)

I appreciate the praise. I constructed the texture by using a small piece of this PD NASA image on Commons and then modified it to better approximate Pluto using information from the PD NASA image of Pluto in true color and Pluto's known albedo and color index. —RP88 12:15, 13 March 2007 (UTC)

Smart! One day I have to learn how to do this. If that wasn't clear by now, I fully agree with IvoShandor. The new image is a lot better (and more certainly free) than the old one. Thanks again! --Stephan Schulz 12:28, 13 March 2007 (UTC)

Go with any new image. That text above does imply that there may be copyrighted material on the ESA website, it came from their webpage so I am not sure how you interpret that as "there is no exception." If they don't own the copyright, they can't freely license it. Either way, it is irrelevant as it seems you have come up with a better solution. IvoShandor 12:09, 13 March 2007 (UTC)

I interprete "Reproduction is authorised, provided the source is acknowledged, save where otherwise stated." as a blanket permission with exceptions that will be explicitely stated. I found no such statement for the image in question. Anyways, the point is moot, as thanks to RP88, we now have a much superior image. --Stephan Schulz 12:33, 13 March 2007 (UTC)

Oh and might I say the new image is far superior to the old one. I will probably just go from on hold to the review, shouldn't take too horribly long as I know you have waited quite awhile on this nomintation. At a glance the article looks good, of course I will know more as I delve in depth. Thanks for addressing this query quickly. IvoShandor 12:11, 13 March 2007 (UTC)

[edit] Should the MPC number be doubled in the lead sentence?

Something14 tried changing the first sentence to

Pluto (IPA: ...), also designated (134340) Pluto (See Minor planet names) ....

but Ckatz promptly reverted to

Pluto (IPA: ...), also designated (134340) Pluto or 134340 Pluto (See Minor planet names) ...

citing consistency with other dwarf planet articles. When choosing between equally good alternatives, consistency is a good guideline, but I don't see that this is the case here. We're obviously not talking about two different designations, merely about two typographical variants of one and the same designation. Giving the form both with and without parentheses appears to be needless redundancy - everybody who has any use for the catalogue number will know that it can be written either with or without the parentheses. Why not improve readability and preserve consistency by eliminating the redundancy from all three dwarf planet articles instead? –Henning Makholm 08:53, 11 March 2007 (UTC)

Personally, I've no preference either way, and will go with whatever the group wants. The previous change was reverted simply because a) it was only changed here, not across the board; b) there was no comment or explanation as to why; and c) the editor who made the change has a long history with regards to edits on Pluto-related articles. --Ckatz^chat_spy 09:05, 11 March 2007 (UTC)

OK, I'll just change it across the board then. The asteroid articles I've sampled use the parenthesis-less form exclusively, so that will be the one I keep. –Henning Makholm 09:12, 11 March 2007 (UTC)

[edit] Page move

This article was moved to (134340) Pluto earlier today, with a note of "To keep the title similar to the other minor planets)". I've reverted it; please discuss such a move before doing it. The page name has been highly contentious in the past, and I don't see any recent consensus to change... Shimgray | talk | 20:44, 11 March 2007 (UTC)

From memory, consensus was to keep Pluto as is, and move the other dwarf planets to Ceres (dwarf planet) and Eris (dwarf planet). I think that there would be a lot of resistance to opening up the debate. Bluap 23:15, 12 March 2007 (UTC)

You're correct - and what fun that discussion was! By the way, your removal of the "disputed" tag was entirely appropriate - the editor who posted it also called for the deletion of Special relativity on the basis that "nearly all of the content, including the title, may be purely unverified". --Ckatz^chat_spy 23:25, 12 March 2007 (UTC)

[edit] This article appears to have next to no citations

I've just added six citations but this article needs about 30 more. What sources are the regular contributors using for the info? Serendipodous 09:37, 13 March 2007 (UTC)

Umm...I count 50 references, and another 20 or so entries in "Further reading" and external references. How much do you want? --Stephan Schulz 09:58, 13 March 2007 (UTC)

Everything from "Symbol" to the second paragraph of "Atmosphere" is completely unreferenced, as is everything from "Orbit" to the second to last para of "Trans Neptunian object", and most of "Planetary status controversy". Serendipodous 13:32, 13 March 2007 (UTC)

Inline cites are neither necessary or always required, IMHO. They should be used to cite any possible information that is "likely to be challenged," (which Pluto's orbital characteristics and symbol are not), as well as anything controversial, (which the name status thing is), although saying "most" of that section is unreferenced is a bit of a stretch. Anyway, just an interested party here, I think I may have made two edits (for grammar) to this article in the past, so neutral opinion weighing in. IvoShandor 13:49, 13 March 2007 (UTC)

Forgot to add, for non-controversial or material not likely to be challenged, a references list will suffice. There is no policy that states anywhere on Wikipedia that inline citations are required anyway. IvoShandor 13:51, 13 March 2007 (UTC)

Nonetheless it does appear to be an issue; the only reason this article failed a GA review was because of inadequate citation.Serendipodous 17:29, 13 March 2007 (UTC)

The article currently is under GA review, and the reviewer is the very IvoShandor you just replied to. It was put on hold due to copyright concerns about an image that has now been replaced. Also, the October 2006 GA review failed for lack of stability, lack of references (29 back then) was only mentioned as a reason to put it on hold, not for the final failure.--Stephan Schulz 17:41, 13 March 2007 (UTC)

Okay then. So it's getting its GA stamp? That's good. Serendipodous 18:11, 13 March 2007 (UTC)

Let's knock on wood. It's not through yet ;-). --Stephan Schulz 18:18, 13 March 2007 (UTC)

[edit] Archiving?

I don't know which threads on this page are still active, but I'm pretty sure at least some of them can be archived now.

OK; I've just archived all threads which have been inactive since Jan 31. I hope no one thinks me too forward for doing so.

Serendipodous 08:35, 14 March 2007 (UTC)

Fine with me...--Stephan Schulz 16:22, 14 March 2007 (UTC)

ehheh. Slight hiccup. While I was archiving, Wikipedia had one of its momentary tantrums and crashed. I think I managed to recover all the lost material but I'm not 150 percent sure. Serendipodous 16:30, 14 March 2007 (UTC)

[edit] Estimates of Neptune's mass

The article currently states that "After the flyby of Neptune by Voyager 2 in 1989, it was conclusively demonstrated that the discrepancies in Neptune's orbit observed by 19th century astronomers were due instead to inaccurate estimates of Neptune's mass." This is puzzling, since Neptune's orbit shouldn't depend on its mass. Could it be Uranus's mass or Jupiter's that was uncertain? Or perhaps it was the distance of Neptune? I'm looking into it now, but if anybody has more info it would be welcome. --Reuben 20:23, 16 March 2007 (UTC)

Neptune's orbit does indeed depend upon its mass - due to the fact that its mass affects the degree to which its orbit is perturbed by other massive objects in the solar system. —RP88 21:46, 16 March 2007 (UTC)

Only at higher order. The direct effect of Uranus on Neptune, for example, doesn't depend at all on Neptune's mass. It's only when Neptune perturbs Uranus, which then causes a slightly different perturbation of Neptune, that Neptune's own mass enters into it. That's a tiny, tiny, tiny effect.

The real reason here appears to be that the residuals in question were not in the orbit of Neptune but Uranus, which was much more well known at the time. They were actually using observations of Uranus going back to the 1700s, while Neptune had only been known for less than a century. Neptune was more massive than thought at the time, so the Uranus residuals were calculated based on a too-small Neptune. --Reuben 22:00, 16 March 2007 (UTC)

The existing refs confirm that Planet X / Pluto was predicted based on residuals of Uranus, not Neptune (until Neptune was added in much later by Pickering). Edited accordingly. --Reuben 22:58, 16 March 2007 (UTC)

Fair enough. —RP88 00:16, 17 March 2007 (UTC)

[edit] Does this still need to be Semi-Protected?

I think the whole public interest in the "is it a planet" matter has long died. Can this be opened back up? JaMiE P 22:12, 19 March 2007 (UTC)

If you want to edit, log in--Heliac 18:17, 30 March 2007 (UTC)
As soon as it's opened back up the Vandals will start within 24 hours as they have in the past. Both fortunately and unfortunately many people still feel very strongly about the Pluto issue. The unfortunate side of this is some cannot contain there emotions to remain NPOV and so they vandalize the page (akin to the way terrorists try to get thier way.) to try to force the issue. The fortunate side is those that can contain thier emotions do proceed to discuss the manner is CIVIL manner and add to the topic and utilize proper avenues to have thier views addressed. So for now my answer would have to be yes it still needs to be SP, for at least another 3 months, to help ensure vandalism is kept to a minimum. Abyssoft 04:29, 31 March 2007 (UTC)

[edit] GA Hold Review (2nd time)

It looks like the original reviewer has abandoned this article. I have extended the hold, and am taking over the review since they never put a hold notice on WP:GAC. Based on criteria at WP:WIAGA, the article is fairly well written, broad, NPOV, and uses images appropriately. It would seem that the referencing of the article needs improvement, specifically in areas where numbers or data are quoted, or other assertions of fact are made. Some examples of where this needs fixing:

Section titled Symbol is entirely unreferenced.
Section titled Physical characteristics makes the following unreferenced subsections:
- Appearance
- Mass and size
- Orbit
Subsection of Moons titled Charon is unreferenced.
Commemoration as a planet section is unreferenced.
New discoveries ignite debate is unreferenced.
There are other parts that may be unreferenced. Check over these to see that I haven't missed any.

Also, the format of references is inconsistant. Some refs are simply URL links. Minimum bibliographical information is missing from some references. Ideally, each reference should contain:

Author's name (if availible)
Title of article
Title of larger work (if applicable)
Publication information
Date of access for websites.

If you would like, you may use templates found at WP:CITET to organize your reference information. It isn't required, but I have found them helpful. More information on citing sources can be found at WP:ATT and WP:CITE

As a whole, given the level of activity this article recieves, I am certain these fixes can be made in the next week. A hold will stay for 7 days. If the required changes are not made within 7 days, I will have to fail the nomination. If you have any questions, or would like me to review the article once the changes have been made, see me on my talk page. --Jayron32|talk|contribs 04:05, 21 March 2007 (UTC)

Just FYI, I did put it on hold, I just removed it when my original concerns were met with the note that I didn't have time to finish the review in as detailed a fashion as I wanted to. Sorry for any confusion. IvoShandor 14:35, 9 April 2007 (UTC)

[edit] Orbit section

Much of the info for this section is unsourced, and the only sources I can find for it are mirrors of this page. Any thoughts on where the info came from? Serendipodous 13:30, 26 March 2007 (UTC)

I think the best source is likely to be this one, which is not available online.

Malhotra, R. and J. Williams, The heliocentric motion of Pluto, in Pluto and Charon, D.J. Tholen and S.A. Stern, eds., Arizona Space Science Series, Univ. of Arizona Press, Tucson (1997).

There are also some web sites that give some of the info and reproduce some of the figures from Malhotra: [1], [2]. --Reuben 20:56, 26 March 2007 (UTC)

Another useful web page with a slightly different view on the orbit's precesion is [3] Deuar 14:29, 28 March 2007 (UTC)

By my count, we only need five more citations, so I've taken down the section heads and simply flagged them with {{Fact}}. Serendipodous 22:26, 26 March 2007 (UTC)
Oh, and could you double check to make sure that I've flagged no 43 with the correct citation? I'm not sure. Serendipodous 22:32, 26 March 2007 (UTC)

I don't think that Malhotra actually wrote that web page; it looks like the author just took the figures from the chapter in Pluto and Charon and intended the comment at the bottom of the page to credit their source. It's a little confusing, though. --Reuben 22:58, 26 March 2007 (UTC)

Actually, it seems that the #Heliocentric distance and #Trans-Neptunian object sections are often covering similar ground. Perhaps the entire rbit explanations should be rearranged (and put all into the "Orbit" subsection). For example, like

Present orbit
Long-time orbit evolution
Neptune-avoiding 2:3 resonance
Heliocentric distance

I'm willing to give it a try. Deuar 14:56, 28 March 2007 (UTC)

Fine with me. Serendipodous 15:01, 28 March 2007 (UTC)

If anyone can do a decent rewite it's either Deuar or Serendipodous. And right now moving those items and reworking them could only help to clear up parts of the article. Abyssoft 15:07, 28 March 2007 (UTC)

Thanks. That's sweet :) I've given this article a general cleanup, but I'm afraid I can't really touch the orbital section, as my knowledge of dynamic physics is, well, not. I don't want to risk a misinterpretation on my part. Serendipodous 16:20, 28 March 2007 (UTC)

Eeep. Sorry Deuar. I hope I didn't interefere too much with your plans, but there was so much repetition in that section I just had to get rid of it. Once I got rid of all the repeated info, an entire section basically disappeared.

Yeah - I didn't have time to reduce it down yesterday, unfortunately. Great that you did that. I think the "Neptune-avoiding 3:2 resonance" section still needs some editing to clear up some details. Deuar 12:58, 29 March 2007 (UTC)

One thing; the paragraph beginning "When Neptune approaches Pluto from behind..." (now the third para in the "3:2 resonance" section) may be a repeat of the info you added in "Long term orbit evolution". I'm not sure though.

Yes, it's the same stuff I think. In fact I was thinking last night that my attempt at the long-term orbit evolution section was pretty bad, and it needs a complete rewrite. Also, what is really needed for a decent understanding is figure 8.51 from here. Maybe i'll try to generate a similar figure and include it. Deuar 12:58, 29 March 2007 (UTC)

Another thing; I took a gamble and combined the mention of the Kozai mechanism with the mention of Pluto being 8 AU above Neptune when it crosses its orbit. I am 99.99 percent sure that they refer to the same thing. I also combined the "nodes" paragraph with the Kozai mechanism paragraph because it seems to me that they are also referring to the same thing.Serendipodous 07:58, 29 March 2007 (UTC)

It looks like it. Furthermore I'm pretty sure that the Kozai mechanism is what is responsible for the "long-term orbit evolution". In this case, I think all the three subsections (2:3 resonance, other factors, long-term evolution) are not independent, and should be co-massed somehow into one block. Deuar 15:26, 29 March 2007 (UTC)

Well, that's a bit out of my depth, but I can try to get someone over here who might have some idea how to do it. Serendipodous 15:41, 29 March 2007 (UTC)

Just explaining the rationale behind my recent re-arrangement. Since the 2:3 resonance is a major issue by itself I thought having its own short section might be useful. Then all the gory details of how they avoid each other can be belabored in a "neptune-avoiding orbit" section. I put the inclination issue in first there because I think it's easy to understand, whereas the timing issue is a bit more involved. Finally issues related to why this configuration is stable and how it librates can be put in the "long-term orbit evolution" section. Deuar 20:42, 30 March 2007 (UTC)

Serendipodous asked me to give the orbit section a once-over, so that's what I've done. I've cut a couple of bits where you had numbers with no citations and very little hope of finding them (the 13/20 year alternation, the linear separation of the two orbits), but in both cases I've replaced them with similar or superceding information that I could source. It's all referenced now, at least. I can see you've done a lot of copyediting and rearrangement of this section already, so I've stuck to the structure you've already developed, and done my best to tighten up the science a bit. I hope it's okay. Spiral Wave 03:38, 1 April 2007 (UTC)

Super! That's exactly what it needed. Your edits were a massive qualitative improvement. Deuar 15:56, 2 April 2007 (UTC)

[edit] Significance of Ketakar

The article gives no indication of why Ketakar's prediction of another planet is significant. In the late 19th and early 20th centuries, there were dozens of people predicting planets beyong Neptune. Without having read his original article, I don't see any possibility that Ketakar's predictions were more well-founded than any others, since Pluto's mass is far too small to significantly perturb the other planets. The work of Lowell and Pickering is notable for several reasons: first, their predictions were quite influential, and helped lead to the actual discovery of Pluto, even if the apparent accuracy of their predictions was fortuitous; and second, their calculations were generally correct, but they were working at the edge of significance. They were doing valid science even if the conclusions were not correct. As for Ketakar, it seems that he is being promoted mainly for nationalist reasons. It's possible that his work was of similar validity to that of Pickering and Lowell (and also quite possible that it wasn't - it would take expert review of his article to find out!), but it doesn't appear to have been similarly influential. I don't see the notability. --Reuben 21:16, 26 March 2007 (UTC)

I agree, but the one thing I've learned in a year of editing astronomical articles on Wikipedia is that if you revert the work of the Indian nationalists, they'll just put it back in again. And when you make your case on the discussion board, they'll accuse you of Western imperialism.Serendipodous 21:38, 26 March 2007 (UTC)

Screw it. Bring 'em on. If Indian nationalists feel that it bolsters thier nation's image to claim that one of their own was the first to provide a vaguely correct location for a non-existent planet, let them make their case. Serendipodous 15:18, 28 March 2007 (UTC)

[edit] This article only mentions the Kuiper belt once

Really needs to have a section to itself, don't you think? Pluto is a Kuiper belt object; indeed it is technically the largest Kuiper belt object. That aspect of its identity should be explained. EDIT: added Kuiper belt section. Serendipodous 15:28, 28 March 2007 (UTC)

[edit] Triton image

This Voyager image shows the atmosphere of Triton in profile. I was wondering if anyone thought it would be a good idea to include it as describing the probable appearance of Pluto's atmosphere.

Serendipodous 18:29, 28 March 2007 (UTC)

If you can find a published scientific work claiming that the atmosphere of Pluto is likely to be similar to Triton, then there may be merits in including it. Otherwise, it's probably complete speculation on our part, and therefore shouldn't be included. Richard B 11:50, 30 March 2007 (UTC)

Here are a few:

[4] [5] [6] [7]

I'm not sure if they alone would be enough to justify the image inclusion. Serendipodous 18:08, 2 April 2007 (UTC)

[edit] no subject

I really believe that since Puto is so small that it has been considered a dwarf planet for so long that you should say that it is like you do with the dwarf planet Eris. —The preceding unsigned comment was added by 12.169.12.140 (talk) 21:08, 28 March 2007 (UTC).

[edit] Composition

The image of Pluto's interior doesn't appear to refer to any section of the article. The composition section only refers to the surface. EDIT: Expanded section. Serendipodous 11:07, 29 March 2007 (UTC)

[edit] True anomaly

True anomaly is not given in the infobox. This is very annoying, especially if you actually want to use the orbit parameters for something. Why can't we give all six orbital elements is we go so far as to give five? Of course, surprise, surprise, there is no reference for the values already given. Well, anyway, that's my two bits worth of complaints. Deuar 16:35, 29 March 2007 (UTC)

The true anomaly is continually changing though, it's not a "constant" (to zeroth order) like the longitude of ascending node and chums... it might vary rather slowly for Pluto, but then should we include it for Neptune too? Then for Uranus? That's a slippery slope, and you need a well-defined cut-off before you start, else we'd have to update the Mercury entry every 12 hours. If you feel it should be included for distant objects, you should probably take it up with WP:ASTRO, they govern all things info-boxy. Spiral Wave 08:54, 30 March 2007 (UTC)

Yeah, I hear what you're saying about not being a zeroth order "constant". Epoch would also have to be given (hell, it should be given anyway, with or without giving the position along the orbit). I would of course be for putting it in for all the planets. It's not such a huge slippery slope as might be supposed because e.g all the minor planets already have Mean anomaly and epoch specified. Still, it would be good to put it up for discussion at WP:ASTRO beforehand, which I, at least, don't feel up to at the moment ;-) Deuar 17:02, 30 March 2007 (UTC)

Ah, I see, I hadn't realised that the M.A. was included for the minor planets. That strengthens your case a fair bit, I would've thought. (And since it's given for Eris and Ceres, surely it should be given for Pluto? Is it an oversight from the reclassification?)

Idly, I wonder if there's a case for simply giving the eccentric anomaly instead; then the user could easily calculate the mean and true anomalies for themselves if they wished, assuming a well-determined orbit. I suppose the problem is that not everything is that well determined, and perturbations tend to screw it all up. Spiral Wave 18:16, 30 March 2007 (UTC)

[edit] GA Failed: Explanation

This article has been on hold for over a week. Significant improvements HAVE been made, and it looks really close. I still count about a half-dozen {{fact}} tags that need to be resolved, but once that is done, the article should be GA ready. Please feel free to renominate when all fixes have been made. Good luck and happy editing! --Jayron32|talk|contribs 14:49, 30 March 2007 (UTC)

Uh, guys, that wasn't me. But the person who posted it had a problem with his/her signature, which caused all the sections below to bunch up into one massive block. I moved it down here to stop it causing problems. Serendipodous 14:11, 30 March 2007 (UTC)

Sorry for the damage. I repaired it and returned my sig. Again if you have any questions, please see me at my talk page. --Jayron32|talk|contribs 14:50, 30 March 2007 (UTC)

This article is very well written and well referenced. The above issues have been addressed, and I am happy to promote this to GA status. Dr. Cash 22:28, 2 April 2007 (UTC)

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