Talk:Neptune

Neptune

The statement "Discovered on September 23, 1846,[1] Neptune was the only planet found by mathematical prediction rather than by empirical observation." is misleading. It may be more accurate to say that "Discovered on September 23, 1846,[1] Neptune was the first planet to be found by mathematical prediction rather than by empirical observation." In the last ten years or so many planets have been found outside our solar system by mathematical prediction .

Good point. Serendi^podous 15:42, 6 March 2009 (UTC)

Wouldn't "the only solar planet found" make more sense, I actually found the new wording more confusing. As in this article I'd take planet to mean a solar planet unless otherwise specified or obvious from context. 82.132.136.201 (talk) 20:47, 13 March 2010 (UTC)

Good counter point. Is the average reader going to assume "only planet found" to mean "only planet found, including extrasolar planets"; or is it more likely the average reader is going to assume "first planet found" to mean there were other solar planets discovered by this method? I propose reverting back to "only planet found..." In this context most readers, I believe, will safely assume this to mean "only solar planet found...".Racerx11 (talk) 22:20, 3 August 2010 (UTC)

Naming Section

Umm.. "The demand for a mythological name seemed to be in keeping with the nomenclature of the other planets, all of which, except for Earth, were named for Roman deities.[33]"

Isn't Uranus a greek deity not a roman one? —Preceding unsigned comment added by 69.63.50.213 (talk) 10:04, 6 March 2009 (UTC)

Well spotted! :-0) Serendi^podous 10:33, 6 March 2009 (UTC)

What is the Roman name for Uranus? --116.14.26.124 (talk) 03:50, 27 June 2009 (UTC)

Ah, I just found out. It's Caelus. --116.14.26.124 (talk) 05:30, 30 June 2009 (UTC)

Shouldn't the naming section include a brief mention that "Neptune" was chosen (and Oceanus proposed) due to the planet's blue colour? Glaurung quena (talk) 01:28, 19 January 2010 (UTC)

Yes I think it would, but a reliable source is needed.—RJH (talk) 17:10, 15 March 2010 (UTC)

Earth also has a name derived from classical mythology, although it is rarely used in common parlance: Gaia, the wife of Uranus (Ouranos).82.176.209.52 (talk) 06:14, 4 January 2011 (UTC)

Hebrew Name?

Why was the sentence about a Hebrew name thrown in as an afterthought in the English Language Wikipedia? I'm sure other countries have given Neptune their own names in their own languages but Israel played no part in the discovery of this planet. Do we need to add the lines that Neptune is called Haiwangxing in Mandarin, ket in Thai and the Greeks stubbornly call it Poseidon? . 97.85.185.160 (talk) 08:37, 8 April 2010 (UTC)

Odd. The planet's Chinese/Japanese/Korean name should be mentioned. It is for every other non-classical planet. I believe it's "sea king star" or "water king star". Serendi^podous 09:06, 8 April 2010 (UTC)

Added. I know this site's aversion to nineplanets.org, but given the nature of the fact being sited, I don't think it's an issue here. Serendi^podous 09:20, 8 April 2010 (UTC)

The Chinese/Japanese/Korean name makes some sense in the cultural/mythological context for the classical planets. I'm not so clear they are appropriate for more recent discoveries like Neptune. In the latter case it's just a name translation and would appear to provide no other value.—RJH (talk) 14:59, 8 April 2010 (UTC)

The site you just used has the line: Hebrew Shemesh Kochav Chama Nogah Eretz Yareach Ma'adim Tzedek Shabtay Uranus Neptune Pluto. So in Hebrew it is still 'Neptune'! Why have the added WP:Cruft of it's various names added in as afterthought to a paragraph focused on it's original naming and discovery? Just remove the whole line. If any of the relevant personalities were Jewish and it was documented as important to their faith; I could see the inclusion but it more belongs in a trivia section. 97.85.185.160 (talk) 10:43, 8 April 2010 (UTC)

Obviously that page hasn't been updated since before 2009. The fact that the planet has a Hebrew name is worth noting, I think, as much as its Chinese name is. And Uranus and Pluto both have their Chinese names listed. Pluto even has its Gujerati name listed. Serendi^podous 11:03, 8 April 2010 (UTC)

I disagree about the notability of adding a name from another language to a English article in the section about the original naming of the planet. What happens on other articles or other websites isn't really relevant to this page. The paragraph in mention is all about the original discovery and naming not later naming. Alatari (talk) 12:25, 8 April 2010 (UTC)

Why do you feel it is not notable? Why should this article be Anglo-centric, just because it's in English? Serendi^podous 12:35, 8 April 2010 (UTC)

This planet was unknown till modern times and these names are popular namings in 2009 by non-science sources. This is a first rate, front page featured article and those lines read as afterthoughts and are completely unrelated to the discovery and naming of the planet. You start adding each individual countries choices to not use the Anglo name then you open up the article to a crufty laundry list trivia section. The other older planet articles were written from history and the other new planets articles have had the same crufty looking lines added. The sources cited are not reliable science sources. If we add in the choice of name from Israel then we need to start adding the name (in their native script) from India, Bhutan, Indonesia, Iran, Russia and whoever else want's to not go with the English version. If you can point out a scientific journal of international renown catering to the various other names then I'll remove my objection. Otherwise I'm sticking with a deletionist-cruft-protectionist stance. Alatari (talk) 13:42, 8 April 2010 (UTC)

I have to agree. Non-English names make sense when they are relevant to mythological beliefs, provide an etymology or have some other cultural significance. Otherwise it's just serving as a translation dictionary, and we all know that Wikipedia:Wikipedia is not a dictionary. :-) —RJH (talk) 15:02, 8 April 2010 (UTC)

So are we to remove those names from the Uranus and Pluto articles as well? Seems like a pointless loss of information. Serendi^podous 17:29, 8 April 2010 (UTC)

Yeah, this is kind of a nit-picker. But if the names are not solidly referenced, then it's another argument for their removal.—RJH (talk) 19:16, 8 April 2010 (UTC)

It is poor style to just throw that sentence in at the end of a history of the planets naming. It looks like an afterthought or maybe wiki vandalism when I find a single tossed in fact with no transition. If there is a cultural jealousy of the Europeans getting the sole rights to name Neptune and Uranus then that is notable and would be an excellent angle to include this information with. For years we were supposed to believe that Columbus found the new land first but we find out now that Scandinavians had made their way there. The land bridge was supposed to be the sole way humans entered the Americas but now we find that people made their way in boats along the Atlantic ice pack. It seems possible that Neptune or Uranus had some name in some ancient culture as a roaming star and that would make a notable addition here. Whatever I just don't want to see a growing list of all the cultures that decide to use other names for Neptune/Uranus added her for like was said above Wikipedia:Wikipedia is not a dictionary. And please, please if you're going to take the time to include the Hebrew script for the name then be respectful of the Asian cultures and use their scripts in the sentence. Alatari (talk) 07:21, 15 April 2010 (UTC)

I removed it, though I still think the removal was unnecessary. No one has yet complained that Uranus and Pluto have their alternate Asian names included. I don't see why this issue is so controversial. Isn't it good enough that the information fills a hole in people's knowledge- what do cultures with no ties to Neptune the sea god call the eighth planet? Seems like information worth knowing to me. Serendi^podous 09:25, 15 April 2010 (UTC)

I agree that this is information that should be included, for the reason you've given: it provides insight into cultures with no ties to Neptune as a sea god. Please add it back. --Gyrobo (talk) 14:58, 15 April 2010 (UTC)

As long as its not just listed as the non-English equivalent name and provides some tidbit of cultural interest (such as the meaning or etymology of the name), it's probably of some value to the article.—RJH (talk) 15:08, 15 April 2010 (UTC)

I restored the Sinospheric name, in keeping with the other articles.

At first I was in favor of retaining the Hebrew as well, but then I noticed that Hebrew WP is still at "Neptune". There are all sorts of proposals for what to call things; that doesn't mean they're notable. I do think it's interesting that other languages may substitute a native equivalent for Neptune; Greek does that with Poseidon. But other than Chinese et al., everyone else appears to be just borrowing the name Neptune, even in India, though it's a bit distorted in Celtic. But this is worth exploring further: Although Bengali just calls it "Neptune", in Hindi WP the article is listed at Varuna, though in the article itself (which is just a stub) it's "Neptune" again. I have no idea how relevant that is. But in Chinese, Japanese, Korean, etc, the sinospheric name is the only one that's current, and is not in competition with the Latin name. kwami (talk) 18:11, 15 April 2010 (UTC)

Maybe we need a vote to obtain consensus. There is a larger issue here. I believe that having a list of names of any important object in different languages is part of the human knowledge of that object, and as such belongs in an encyclopedia, at least for some selected set of important objects.

To me, that information is not trivia and not just dross relevant to a few readers (fancruft). It may be relevant that we currently have kid's bilingual cartoons in Mandarin and Spanish on TV. Languages are as valuable as astronomy to a rounded education.

For example, a child doing research in elementary school could find her imagination and desire to learn stimulated by exposure to concrete examples of many languages for a thing about which she is learning. Creating links between separate fields of study can literally add a new dimension to education.

That will almost never happen in school, so it is a potentially valuable contribution by her online encyclopedia. Within limits, a multidisciplinary approach to education (in the old pedagogical meaning) makes good sense.

David Spector (talk) 13:43, 1 June 2010 (UTC)

The issue you are raising is more general than the topic of the planet Neptune, so I think it should have a broader perspective and a wider discussion. If you are going to include a few language translations, then by extension you need to include every language for comprehensiveness. You will also need pronunciation information, etymology for each language and so forth. Personally I'm against such a significant expansion of scope. That's what the wiktionary is for.—RJH (talk) 15:41, 1 June 2010 (UTC)

Related

The chemical element Neptunium, discovered by Edwin McMillan and Philip H. Abelson in 1940, was named after the planet Neptune. In the periodic table of the elements it lies between Uranium and Plutonium, which were named after Uranus and Pluto respectively.<ref name="pr57">{{cite journal | title=Radioactive Element 93 | year=1940| author=Mcmillan, Edwin | journal=Physical Review | volume=57 | page=1185 | doi=10.1103/PhysRev.57.1185.2 }}</ref>

—RJH (talk) 21:03, 20 April 2010 (UTC)

Where did this line come from? This article or Neptunium? Alatari (talk) 06:10, 14 May 2010 (UTC)

I'm not sure where to put it. There isn't an "in culture" section and given the fight we've had over the additional names, I'm a bit wary of adding it to the name section. Serendi^podous 18:22, 21 April 2010 (UTC)

The elements being named in conjunction with the planet was already in the articles last I looked. Maybe it's missing from this one? It's notable that scientists decided to name new elements after the planets since that's how the elements got their names. Alatari (talk) 19:01, 21 April 2010 (UTC)

Don't get me wrong; I want this to be included. Problem is that I've got into various fights over their inclusion, similar to the one above. I had to find an additional historical reference to include Uranium, and Plutonium only snuck in behind Pluto the Pup. Serendi^podous 11:08, 12 May 2010 (UTC)

It is unfortunate that Classical planet doesn't cover Uranus, Neptune or Pluto. We could perhaps do with a "Planets in culture" article where we could file this type of information.—RJH (talk) 18:42, 12 May 2010 (UTC)

Pronunciation

Why are there two pronunciations?
I thought Wikipedia used only one diaphonic transcription per article name, which is not to specify any one dialect, but a generic transcription for them all. And yet we have a non-North American transcription first and a North American transcription second. This is inconsistent with the other planet names which only have one for each planet name, not to mention other generic articles. --124.180.44.40 (talk) 05:55, 28 May 2010 (UTC)

Probably because the recording was of GA. But you're right: we don't transcribe the dialect of the recording elsewhere. — kwami (talk) 06:57, 28 May 2010 (UTC)

Trojans

The discovery of the first L5 Neptune Trojan was reported in Science (Science 10 September 2010: Vol. 329. no. 5997, p. 1304). The corresponding section in the article needs to be updated. Siravan (talk) 01:56, 23 September 2010 (UTC)

Vandalism

The summary syayes "Temperatures at the planet's centre, however, are approximately 5,400 K (5,000 °C)". The 2 references are unreachable, and this claim is not substantiated in te section of the article devoted to the planet core. Stephen Charles Thompson (talk) 05:03, 23 September 2010 (UTC)

I had no problem reaching the Suomi, Limaye and Johnson (1991) article. The illustration in that article confirms the statement. I'm not sure what the problem is with the other citation; perhaps their web server is malfunctioning?—RJH (talk) 18:56, 23 September 2010 (UTC)

Google works wonders: "Interior Models of Jupiter, Saturn and Neptune" -> https://www.gsi.de/informationen/wti/library/plasma2006/PAPERS/TT-11.pdf -- Kheider (talk) 19:06, 23 September 2010 (UTC)

Infobox image

Is there a reason why File:Neptune.jpg is used instead of the higher resolution File:Neptune Full.jpg? Nergaal (talk) 19:55, 11 October 2010 (UTC)

I don't think it matters; in either case the image downloaded is at the resolution specified on the page. I.e. you don't get the full image in the download. Also, I don't think either image is correct, color-wise. But the first one looks a little more natural.—RJH (talk) 21:35, 11 October 2010 (UTC)

OK, let's settle this once and for all

Uranus: cyan or aquamarine?

Personally, I vote aquamarine. Keraunos obviously votes cyan. Anyone else wish to contribute to this hugely important debate? Serendi^podous 10:14, 20 December 2010 (UTC)

I was having the same debate with myself after seeing his edit. See PIA00032: Uranus in True and False Color (as human eyes would see it): http://photojournal.jpl.nasa.gov/catalog/pia00032 -- Kheider (talk) 11:55, 20 December 2010 (UTC)

Many sites report either light blue or blue-green. Schmude (2008) notes that the color varies with telescope aperture. For what it's worth, I get 10,700 ghits for color uranus aquamarine, 7,900 ghits for color uranus cyan, 302,000 ghits for color uranus "light blue" and 351,000 ghits for color uranus "blue-green".—RJH (talk) 21:14, 21 December 2010 (UTC)

"Blue-green" redirects to cyan on Wikipedia, though I'm not sure whether it should. After all, viridian is blue-green, and no one would confuse it with cyan. Serendi^podous 22:38, 21 December 2010 (UTC)

Perhaps it could says something like, "The color of Uranus is considered light blue or blue-green (cyan), with the hue being dependent on the aperture of the telescope used to observe the planet." Citing Schmude above.—RJH (talk)

Well, the only reason this is an issue is to distinguish the colour of Neptune from the colour of Uranus. Neptune is blue, Uranus is blue-green. So I suppose we could just say that. Serendi^podous 17:57, 22 December 2010 (UTC)

Adams

The account of John Couch Adams in the Discovery section differs markedly from the cited references and also other Wiki pages. I'm not an astronomer so hesitate to plunge in. However..

The history page cited says that the 1843 letter to Airy was a request for data on Uranus not the results of his calculation. His claimed letter was to James Challis, not Airy in Sept 1845 and the cited 1846 paper in RAS Noticies doesn't contradict this. Chris55 (talk) 17:51, 19 January 2011 (UTC)

Actually, I think he says he did both. He first requested observations, which he received in February 1844. He then says he communicated the results of his first calculations Challis in September 1845, then sent slightly refined calculations to the Astronomer Royal (Airy) the following month.

"After obtaining several solutions differing little from each other, by gradually taking into account more and more terms of the series expressing the perturbations, I communicated to Professor Challis, in September 1845, the final values which I had obtained for the mass, heliocentric longitude, and elements of the orbit of the assumed planet. The same results, slightly corrected, I communicated in the following month to the Astronomer Royal."

—RJH (talk) 19:41, 19 January 2011 (UTC)

You don't get my point: the current article claims he had some results in 1843. That appears to be false and misleading. In fact, it appears that in Sept 1845 he was still investigating Biela's comet - whether he thought this was responsible for Uranus's perturbations I'm not sure. It would seem that neither he nor Le Verrier got very close to the truth in 1845 - the real action happened in 1846. Chris55 (talk) 19:56, 19 January 2011 (UTC)

I should perhaps clarify about your quotation: the account you quote by Adams is the historical one made in 1847 that has been widely questioned. If they were convinced about it in September 1845 why was it not seen by others at that time? In addition, the calculations by Adams seem to have been much less accurate than those of Le Verrier. Chris55 (talk) 23:46, 19 January 2011 (UTC)

No problem. I understand that the issue was controversial and any improvements are appreciated, if you can find suitable sources. Thanks.—RJH (talk) 23:56, 19 January 2011 (UTC)

A problem with your edits is your statement that begins, "After reviewing the documents, historians suggest that...". It appears that the text is claiming that all historians agree with this view, whereas only the authors of the cited source make that statement. You pretty clearly made that assertion by removing the "some" from the previous wording, so you'll need additional citations to affirm that statement.—RJH (talk) 16:49, 20 January 2011 (UTC)

you're right - the word "historians" is entirely redundant in that sentence now, I've removed it. Chris55 (talk) 18:36, 20 January 2011 (UTC)

That works for me. Thanks.—RJH (talk)

Neptune should be visible to the naked eye

While Brian Skiff failed to see it from Arizona, he says that it should be "straightforward with patience from Chile or elsewhere in the south."

If it is in opposition and high in the sky and from a location like Chili where you often have Bortle class 1 skies with limiting magnitude of +8 (if you have good eyes), then it should be visible. Count Iblis (talk) 01:13, 12 April 2011 (UTC)

That is really pushing the limit. Brian Skiff glimpsed HD 85828 (calling it mag ~8), but SIMBAD shows it as only mag 7.7. Bottom line is that even a professional failed to see Neptune with the naked eye. -- Kheider (talk) 01:32, 12 April 2011 (UTC)

Well, perhaps there aren't enough of these "star parties", like the Oregon star party in the Southern Hemisphere. Count Iblis (talk) 14:28, 12 April 2011 (UTC)

Edit request from 204.113.118.138, 6 May 2011

The beginning of the article says "Neptune is the eighth and farthest planet from the Sun in our Solar System." Shouldn't it say "the Solar System" instead of "our Solar System?"

204.113.118.138 (talk) 19:54, 6 May 2011 (UTC)

Yes indeed. Very well spotted. :) Serendi^podous 19:56, 6 May 2011 (UTC)

 Done by serendipodous. Monkeymanman (talk) 22:07, 6 May 2011 (UTC)

Typo in math markup of reference #12 mass ratio with earth

The '\b' in begin and the '\f' in frac are causing an error in reference 12 mass ratio with earth

Failed to parse (syntax error): {\displaystyle �egin{smallmatrix}�rac{M_{Neptune}}{M_{Earth}} \ =\ \frac{1.02 \times 10^{26}}{5.97 \times 10^{24}} \ =\ 17.09\end{smallmatrix}}

Should be

${\begin{smallmatrix}{\frac {M_{Neptune}}{M_{Earth}}}\ =\ {\frac {1.02\times 10^{26}}{5.97\times 10^{24}}}\ =\ 17.09\end{smallmatrix}}$

Not sure how to report this so I'm trying this Talk page thing. Please delete and accept my apologies if I goofed.

96.235.180.16 (talk) 18:22, 11 May 2011 (UTC)

I fixed the error. Ruslik_Zero 19:12, 11 May 2011 (UTC)

Calculation of position

I thought I remembered hearing once that the theoretical calculation of Neptune's position was actually done incorrectly, and it was only through a piece of good fortune that the prediction was anywhere close to the actual position where the planet was discovered. The article doesn't seem to mention this, though, so am I remembering it incorrectly? 86.160.208.15 (talk) 20:14, 17 May 2011 (UTC)

Yes I believe you're correct.[1]—RJH (talk) 20:52, 17 May 2011 (UTC)

Thanks. If this is verified I think it should be mentioned in the article. It seems fairly important. 86.181.168.97 (talk) 11:11, 18 May 2011 (UTC)

Note that there is a article Discovery of Neptune that this section summarizes. Hence, I think this should be mentioned there first. I'm not sure whether this point is at a high enough level for mention in a summary. Regards, RJH (talk) 14:48, 18 May 2011 (UTC)

Inconsistencies in date of completion of first orbit

There seem to be some discrepancies regarding the date of 12th July 2011 quoted for the completion of Neptune's first orbit since its discovery on 23rd Sep 1846, and the orbital period given in the info box: 60190 days or 164.79 years.

Firstly, 60190 days from the discovery date is 10th July 2011, not the 12th. (I'm fairly confident I've done that right, but please check my calculation. There were 40 leap years between those dates: every 4th year excluding 1900).

Secondly, the Nasa source cited for the figures in the info box has a few internal inconsistencies of its own, one of which is that the ratio of the orbital period given in Earth days and in Earth years is 365.2500, suggesting that one has been calculated from the other using this naive conversion factor. Both are given to a suspiciously high number of significant figures. The correct ratio is 365.2422 days per year, so at least one of the figures for the period from this source is not correct.

365.25 days is the length of the Julian year, which is used in astronomy. Saros136 (talk) 22:23, 20 May 2011 (UTC)

Really? Ok, my bad. I didn't realise that. But still... if they're saying Neptune's sidereal period is 60190.03 days, why do they say on the next line this is 164.791 x Earth's sidereal period, rather than 164.78845? The numbers given are not consistent. But that's a more understandable (minor) error than what I originally thought. Thanks. Bobathon (talk) 00:40, 21 May 2011 (UTC)

A second source by kpheider is given for the 12th July date which appears to be data output from ephemeris software – it's not clear what figures have been assumed in generating this output.

Another Nasa site referenced here gives a period of 60189 days or 164.79 years, which at least is internally consistent. The date for the completion of the first orbit since discovery by these data would be the 9th July 2011.

I'd be interested to know if anyone can confirm a more accurate figure for the sidereal orbit period of Neptune. But either way, unless I'm missing something, 12th July does not appear to be correct. Bobathon (talk) 03:23, 20 May 2011 (UTC)

Without double checking my work (I am kpheider), the orbital period of an object changes on a daily basis as a result of perturbations by the other gas giants. You can not just assume a single fixed value for the orbital period. -- Kheider (talk) 12:31, 20 May 2011 (UTC)

The definitive source for the July 12, 2011 date seems to be Dr. William Folkner at JPL/Caltech. He's using Neptune's return to the same heliocentric longitude as the defining date. There's a decent summary here. Regards, RJH (talk) 14:49, 20 May 2011 (UTC)

Thanks. I understand that the orbit period is subject to fluctuations, but it seems to me that there are two relevant quantities that can be clearly defined and presented in this article. The first is the mean sidereal orbital period of Neptune (the mean time taken to return to a given heliocentric longitude), and the second is the actual duration of this current orbit (time taken to return to the same heliocentric longitude as the defining date).

For Earth, the mean sidereal period is given as 365.256 363 004 in this reference. Although the uncertainty is not stated, a quantity is never given to twelve significant figures unless it has some meaningful value measurable to at least ten or eleven.

I find it hard to believe that we're not yet able to pinpoint the mean orbital period of Neptune to one part in 100,000. But even if we are, we should be able to present it within error bars, in the form 60189.0 ± 1.2 days, so that the state of knowledge on this quantity is made clear. I haven't seen a recent reference that clearly gives such a figure.

Regarding the second quantity – the duration of the first orbital period since discovery that RJH is referring to – from the source it's not clear if this is a definitive date. The period quoted in the article is 164.8 years; 164.8 years from the discovery date is indeed the 12th July 2011 ±18 days, which is not especially precise. If Dr Folkner has calculated the date of Neptune's return to the same heliocentric longitude and found it to be the 12th July, then that would be the date of the completion of the first period, which is the date I'm interested in, and I think is also the date relevant to this article. Currently it seems that the definitive source is a claim on twitter by Luke Dones that quotes Bill Folkner as saying it was the 12th July! It's hardly encyclopedic.

I'd like to know if anyone is aware of better information than this. Bobathon (talk) 18:47, 20 May 2011 (UTC)

I just double checked my heliocentric values (look at the bottom of the reference, and I still get the same values for RA/DEC.) I originally made the reference in 2007 to correct some mistakes on Wikipedia. -- Kheider (talk) 21:14, 20 May 2011 (UTC)

Thanks, Kheider. I'm sure the JPL ephemeris will be reliable and on the ball. Still, objectively there's no indication of what goes in or what degree of accuracy one can expect on anything that comes out. Is the conclusion that the first period is taking perhaps 3 days longer than an average period? Is that kind of variation about the mean (~0.005%) to be expected for a distant planet?

Still the same questions: when will the first period be completed and what's the degree of uncertainty on that; what's the mean sidereal period of Neptune and what's the degree of uncertainty on that. The ephemeris gives an answer to the first part of the first question, and that's all I wanted to know personally, so thanks for that. If anyone can clarify the other questions, that would be great – I think the article needs it. Bobathon (talk) 22:01, 20 May 2011 (UTC)

I'd like to add an additional comment the reliability of the JPL ephemeris dates. Following Kheider, I used their HORIZONS ephemeris to find the dates of the completion of the 1st, 2nd, 3rd and 4th orbits of Neptune since discovery, and found the duration of these orbits to be 60192, 60197, 60206 and 60208 days respectively. (Running backwards, the duration of the orbits prior to discovery were 60184, 60176 and 60174 days respectively.) I don't believe these large increases are anything like the orbital period variation that Neptune can be expected to exhibit. I would suggest from this that their extrapolation is not designed to be reliable to less than several days over a period of centuries. The ephemeris for July 2011 may be precise, as extrapolation is minimal, but those of 23 Sept 1846 are not reliable to the nearest day. As these are required for the suggested date of 12th July, this date appears to be questionable.

This paper by E.M. Standish of JPL presents some indication of the degree of precision involved in the JPL ephemeris, and figure 8 suggests reliability of heliocentric longitude for Neptune to ±0.5" (=0.03" R.A., I assume) over the period 1600-2200, which would make the ephemeris accurate to within one day for that whole period, and within a few hours over the period since 1846. I'm not sure how this tallies with the dates actually given by the ephemeris for the orbital periods of Neptune.

FYI, the dates the ephemeris gives for heliocentric R.A. of 22 05 40.444 are 1352-06-03 0:30, 1517-03-02 12:48, 1681-12-12 18:54, 1846-09-23 23:00, 2011-07-12 20:57, 2176-05-04 19:07, 2341-03-07 20:14, 2506-01-09 13:30. I based them around 23:00 UT on date of discovery because Galle made the discovery "shortly before midnight" ("The Neptune File", Tom Standage, Berkley Trade 2001, p.121) in Berlin (local mean time UT+0:53). Apologies for the excessively detailed discussion entries, but I felt it was important to establish whether there's any real reason to believe that the date of 12th July 2011 isn't based on duff data, especially if the world is intending to celebrate it in a few weeks' time. So far I don't believe that there is. Bobathon (talk) 14:17, 22 May 2011 (UTC)

I've done some thorough calculations using HORIZONS data, and presented the results here. The correct date should be 11th July 2011, not the 12th as cited in the article. The difference is due to the motion of the Sun during Neptune's orbit (0.0033 A.U. at 70º to the radial vector to Neptune) which throws out the coordinates used in the calculation done by Kheider (and Bill Folkner, who I've had some communication with). I'm too wary of the issues around use of own work / citing blogs / etc. to change the article, but there it is. :) Bobathon71 21:50, 1 July 2011 (UTC)

The problem with this approach is Wikipedia's WP:OR policy. Regards, RJH (talk) 15:57, 3 July 2011 (UTC)

Interesting way to look at it Bobathon71. But I am not sure a barycentric solution is any more proper than a heliocentric solution. I might try and play with this later if I get a chance. -- Kheider (talk) 16:04, 3 July 2011 (UTC)

Thanks for identifying the policy, RJH. It's one I'm very supportive of. Kheider, I'd be interested in what you can find. To me, heliocentric solution seems very sensible for any definition in which the role of the sun is dominant, such as equinoxes, perihelion or anything from the frame of reference of the planet itself; but it doesn't make a lot of sense for anything describing the orbit, or for sidereal years. But I agree, if something like this is defined at all then it will be by some convention that has some degree of arbitrariness about it. Perhaps we could go with '10th-12th depending on definition' as you suggested elsewhere. Bobathon (talk) 01:26, 4 July 2011 (UTC)

Here are a couple of images that might be more convincing: Neptune-Sun distance and Neptune-barycentre distance. Bobathon (talk) 16:23, 4 July 2011 (UTC)

I've made the change given that there are also now notable sources quoting the 11th. And because it's correct :) Feel free to let me know if I'm out of line there. Bobathon71 19:40, 10 July 2011 (UTC) — Preceding unsigned comment added by Bobathon71 (talk • contribs)

I disagree that July 11th is a better solution. I think most people think in heliocentric terms. Neptune physically orbits the Sun, even if the barycenter is outside the surface of the Sun. I will allow the barycentric solution first since it comes a day earlier, but I do not agree that it is a better solution. -- Kheider (talk) 21:28, 10 July 2011 (UTC)

Surely the two plots I referenced earlier (Neptune-Sun distance and Neptune-barycentre distance), as well as the laws of gravity, make it incontrovertible that Neptune takes a far, far more periodic, smooth and Keplarian trajectory around the solar system barycentre than it does around the Sun. Is it the job of an encyclopaedia to reproduce what most people think, or what is in line with the laws of planetary dynamics? The Solar System is a gravitationally bound set of objects, and the Sun is one of them. Neptune doesn't orbit the Sun for precisely the same reasons that it doesn't orbit the Earth. Sorry, I don't mean to sound confrontational at all; I'm interested if you actually have a reason for disagreeing rather than just an opinion... Bobathon (talk) 21:44, 10 July 2011 (UTC)

Neptune orbits the Sun, first and foremost. Yes, the barycenter is outside the surface of the Sun. But you MUST define what "orbit" you are quoting. Now the article defines a barycentric solution and a heliocentric solution. If the heliocentric solution came before the barycentric one, I would list it first. -- Kheider (talk) 21:56, 10 July 2011 (UTC)

I haven't argued against defining what orbit is being quoted, that's fine. The original version didn't define what orbit was in use, so I followed what was there.

I gave reasons why it's clear that Neptune follows a far more typical orbit around the barycentre than the torturous path it follows in its motion relative to the Sun, and you restated an opinion. I'm still curious as to whether you have a reason for your view. You might also want to take issue with the introductory definition of orbit and the references it's based on.

Also, forgive me if I restore something of the two sentences from a previous edit, which were making two separate points, one of which was lost in your alterations. Bobathon71 (talk) 22:56, 10 July 2011 (UTC)

The point of the second sentence is that if you look from the point of view of the Sun at Neptune on 23/9/1846 and again on 11/7/2011, it will appear to be at a different longitude. The reason for this is nothing to do with perturbations: it is because the Sun (from which you are viewing Neptune) has moved. Bobathon71 (talk) 23:36, 10 July 2011 (UTC)

The references I added were definitions of orbit, not barycentre. I added them because the section is on the orbit of Neptune. Please, Kheider, don't act as if you own this page. Bobathon71 (talk) 23:36, 10 July 2011 (UTC)

This article is about Neptune. This is not the article to define and directly reference what an orbit/barycenter is. -- Kheider (talk) 23:41, 10 July 2011 (UTC)

Well, approximations are fine in casual writing but an encyclopedia is about truth. Neptune orbits the barycenter. The Sun orbits the barycenter. It's just considerate enough to stay near it. 12.196.0.56 (talk) 03:15, 11 July 2011 (UTC)

The Sun orbits the barycenter of our galaxy if you want to get that technical. The Sun stays near the barycenter of the solar system because it is 1,047x more mass than Jupiter. -- Kheider (talk) 04:20, 11 July 2011 (UTC)

If you want to get technical, then it's the barycentre of the Solar System, not than the Sun, that smoothly orbits the barycentre of the galaxy. Like every other member of the Solar System, the Sun's dynamics are dominated by its motion within the Solar System. It is continuously being pulled towards Jupiter over a thousand times more strongly than it is towards the centre of the Milky Way. And the pull towards the Milky Way is not only tiny, but it affects everything in the Solar System in precisely the same way, so has no effect on any of the dynamics within the Solar System - at least none we could ever hope to measure. There are very good (and fairly obvious) reasons why the International Celestial Reference System doesn't employ the barycentre of the galaxy as the origin of coordinates. Bobathon71 (talk) 12:19, 11 July 2011 (UTC)

The galactic tide likely effects the Oort cloud. -- Kheider (talk) 15:04, 11 July 2011 (UTC)

True dat. Bobathon71 (talk) 15:55, 11 July 2011 (UTC)

I'm a bit confused by your concerns about the motion of Neptune relative to the barycentre. That's what a barycentric orbit is. Bobathon71 (talk) 15:58, 11 July 2011 (UTC)

Your blog entry shows that in 2011 Neptune was 347,750 km closer (0.0077% closer) to the Solar System barycentre than it was in 1846. (Using heliocentric distances on 1846-Sep-23 23:00 UT Neptune was 30.011455AU from the Sun and on 2011-Jul-11 22:00 30.00795AU from the Sun, for a movement of ~524,000km towards the Suns physical centerpoint.) As you know this movement is also the result of perturbations of Neptune in addition to the Sun going around the barycenter. I still am not sure "the motion of the Sun in relation to the barycentre" is a better statement than "the motion of the Sun and Neptune in relation to the barycentre". -- Kheider (talk) 17:24, 11 July 2011 (UTC)

Ah, I see. When Neptune returns to its discovery longitude, it is at a different radial and perpendicular-to-plane co-ordinates, but neither of these have any impact on the date of completion of its first orbit, no matter whether you're using barycentric or heliocentric coordinates. It will have some minuscule effect on the difference between the two events, because of the tiny change in parallax, but no more than that. So it's not relevant to the paragraph on the date of completion of the first orbit; but it may be worth mentioning in a different paragraph as a general point about the nature of the orbit itself.

The reason the two dates (11th & 12th) are different is because of the tangential displacement of the Sun relative to the barycentre between 1846 and 2011. If you displace yourself sideways, the bearing you take on a distant object will change; whereas if that object moves a similar distance towards you (or vertically), that will have no effect at all. Bobathon71 (talk) 17:48, 11 July 2011 (UTC)

Largest known Kuiper belt object

Where the article has "the largest of the Kuiper belt objects, [[Pluto]]" it should have "the largest known Kuiper belt object, [[Pluto]]." Is there a reliable source that says that people are not likely to find any Kuiper belt objects larger than Pluto? - Fartherred from an untrusted terminal 207.224.85.91 (talk) 17:57, 1 June 2011 (UTC)

The statement about KBOs is questionable in any event, since Eris (dwarf planet) probably has more mass than Pluto. From what I've read, speculation about larger objects beyond 50 AU continues, so the answer to your question may be a qualified "no". Regards, RJH (talk) 18:58, 1 June 2011 (UTC)

I modified the sentence according. Thank you for your observation. Regards, RJH (talk) 14:41, 26 June 2011 (UTC)

Didn't we decide aeons ago that "the Kuiper belt" was defined as the classicals plus the resonants? If so then Pluto is the largest known Kuiper belt object. Serendi^podous 15:09, 26 June 2011 (UTC)

You are correct. My bad. Regards, RJH (talk) 21:59, 6 July 2011 (UTC)

That is one more small error disposed of. User:Fartherred from 207.224.85.91 (talk) 09:37, 9 July 2011 (UTC)

Rotation period revised

The planet's estimated rotation has been revised to 15^h 57^m 59^s. See:

Stolte, Daniel (June 29, 2011). "Clocking Neptune's Spin". The University of Arizona. Retrieved 2011-06-05.

Regards, RJH (talk) 21:50, 6 July 2011 (UTC)

Internal Structure

The internal structure is described quite unconditionally: the reader is given no clue about the high uncertainties, both quantitative and qualitative, involved in these models. Nor is there any information given about how these models were derived. Perhaps the tone needs to be changed.Ordinary Person (talk) 02:45, 9 July 2011 (UTC)

Well, improvements are certainly welcome. But, in cases like this, some caution is needed to avoid weasel words and unnecessary vagueness. Thanks. Regards, RJH (talk) 20:00, 10 July 2011 (UTC)

Superheated is incorrect

In the description of Neptune's internal structure, the word superheated is incorrect. Superheat refers to the number of degrees above saturation temperature for steam. It refers to a temperature between normal boiling and critical temperatures for water at which temperature the water must be under more than atmospheric pressure. If this pressure is suddenly released, the water will suddenly boil. The mantle of Neptune is in the supercritical temperature regime in which there will be no phase transition with decreasing pressure. User:Fartherred from 207.224.85.91 (talk) 09:40, 9 July 2011 (UTC)

Not only is the use of the word superheated wrong, worse yet it lacks a citation. There is no reference given that refers to any superheated fluid in Neptune's mantle. This in a featured article, oh, the horror! User:Fartherred from 207.224.85.91 (talk) 14:48, 9 July 2011 (UTC)

The word superheated was in the second of four contributions added by User:203.129.151.10 at 14:18 hours on the 4th of September in the 2006th year of our Lord. 207.224.85.91 (talk) 15:31, 9 July 2011 (UTC)

I cannot wait for RJH to do all the work. I corrected this one myself. People might still improve upon the state in which i left the article Fartherred (talk) 18:33, 9 July 2011 (UTC)

WP:BEBOLD applies, as always. Thanks. Regards, RJH (talk) 19:55, 10 July 2011 (UTC)

The Times

States that Neptune has today completed one orbit since it was discovered. Jackiespeel (talk) 14:12, 12 July 2011 (UTC)

There was a blurb in the AIAA Daily Launch about it this morning; here's the BBC news link they provided. siafu (talk) 15:49, 12 July 2011 (UTC)

Grammar

Incorrect: "none of the planet's remaining 12 moons were" Correct: "none of the planet's remaining 12 moons was"

The word 'none' does not have to be singular. The Times suggests that it is acceptable to use it as a plural except in the specific cases where it means not one or no one.[2] Hence, I think the wording is okay. Thanks. Regards, RJH (talk) 16:36, 6 August 2011 (UTC)

On Galileo's observations.

It is a very cowardly thing, with the benefit of 400 years of hindsight, to accuse someone of "failing" to see what they "should" have seen and I have no intention of doing so. But having said that, I have a small issue with this:

"... Since Neptune was only beginning its yearly retrograde cycle, the motion of the planet was far too slight to be detected with Galileo's small telescope...."

Using the well-known and freely available Cartes du Ciel software, it is easy to model the movement of Jupiter and Neptune past the stars during the interval in question - 28th December 1612, to 27th January 1613. During that time Neptune moves past two stars of at least the same brightness as it. 30th January 1613 is particularly interesting, as Neptune moves past and very close to what is the brightest star in the area during the time in question. Thus, David Jamieson's findings that Galileo <could> have observed Neptune's motion, despite it being at the prograde/retrograde changeover point, are eminently believable. Old_Wombat (talk) 10:13, 7 September 2011 (UTC)

Just

"Neptune is an intermediate body between Earth and the larger gas giants: its mass is seventeen times that of the Earth but just 1/19th that of Jupiter"

There must be a better way to word this. This is the sort of construction that makes non-scientists laugh at scientists. I proposed removing the "just" but was reverted. Any other ideas? --John (talk) 15:25, 16 September 2011 (UTC)

Well, "and is" should work. Mlpearc Public (Talk) 15:30, 16 September 2011 (UTC)

Yes that makes sense, as does Mlpearc Public's suggestion. There's another issue in that the wording "intermediate body between Earth and the larger gas giants" is ambiguous; the same statement is true of Mars. Perhaps "intermediate-sized body between the terrestrial planets and the larger gas giants"? Regards, RJH (talk) 15:52, 16 September 2011 (UTC)

The statement isn't true of Mars, since it is much smaller than the Earth it can't be considered to be intermediate between the Earth and any larger bodies. siafu (talk) 19:59, 16 September 2011 (UTC)

Upon further reflection, I suppose you might have meant that Mars is intermediate in placement between Earth and the gas giants, which is, I suppose, true, but the sentence makes it quite clear that mass is being discussed. In other news, I'm not sure I understand the objection to the wording enough to be helpful-- guess I'm too much of a scientist. I think it does a reasonable job of imparting the scale of solar system bodies to the layperson, and scale is one of the most important (and IMHO, least appreciated) things to impart when discussing any astronomical topics in lay terms. siafu (talk) 20:47, 16 September 2011 (UTC)

The statement about mass is in a separate clause of the sentence, so it is subject to interpretation. I think it's just better to be unambiguous. Regards, RJH (talk) 21:53, 16 September 2011 (UTC)

updated data available

— Tycho Magnetic Anomaly-1 (talk) 22:25, 26 October 2011 (UTC)

surface gravity

Composition and structure "The planet's surface gravity is only surpassed by Jupiter, making the two gas giants the only planets in the solar system with a surface gravity higher than the Earth". But Saturn has 1.044g surface gravity (or 1.06 in List of Solar system objects by size). So there are three gas giants with sg higher than earth.