Talk:Definition of planet/Archive 5

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'Seven planets' section

This whole section is rather misleading. It's pointless to take all these random quotes from ancient authors when the definition of planet was not a subject of dispute during this period at all. The classical definition of the seven planets was not only "not unheard of", it was the only definition of "planet" in just about every pre-modern culture. Basically, "planet" just meant "light that moves with respect to the celestial sphere". It did not have the implications of being an Earth-like body or anything of the sort.--Pharos 11:46, 16 June 2007 (UTC)

The earliest sources define a planet differently than the later sources, as far as I can tell. I can't go and say "The ancient Greeks believed there were seven planets" if every primary source I can find on the subject tells me that they didn't.

EDIT: I just split off another subsection; I hope that makes things clearer. Serendipodous 12:33, 16 June 2007 (UTC)

I believe you are in error that "the earliest sources define a planet differently than the later sources"; this appears to be a wrong impression on your part from some selections of translated ancient texts. The quotes in the new section you've added are quite ambiguous in character ("planets" in these quotes is likely a gloss for "other planets"), and we're not even sure such wording closely reflects the Ancient Greek original. Now, there should be secondary sources on this: I would like to see some that make note of such a difference between earlier and later classical understandings of "planet", because, frankly I've just never heard of anything like this and it sounds a bit idiosyncratic.--Pharos 05:02, 18 June 2007 (UTC)

Believe me, I've been looking for secondary sources on this. I'm not trying to push an agenda here; I had no idea about this until I started trying to source the "History" section. The fact is that Ptolemy unequivocally lists five planets distinct from the Sun and Moon. I know this because he has separate sections in the Almagest for "the Sun", "the Moon" and "the Planets". I can see how the Plato and Aristotle references might be considered ambiguous but it's hard to see how you could argue against the lines from Hygius and Manilius. I've been to practically every library in London trying to sort this out. I even contacted a number of professors of the history of astronomy. They agreed that this ambiguity existed, but couldn't offer me any assistance in tracking it down. Serendipodous 05:35, 18 June 2007 (UTC)

Yeah, I know you're not trying to push an agenda or anything. But I do think in your zealous pursuit of referencing you've unintentionally strayed a little in your interpretation of primary sources, to the point of WP:OR really. Whether classical writers ever used "planets" as a gloss for "lesser planets" in the way that we use "animals" as a gloss for "non-human-animals" is an interesting question, and the idea that there was actually some sort of change in writer's appreciation of this idea over the centuries an even more interesting one. But that is a question for scholars only, not us. Because the fact is that we do have plentiful secondary sources on this, and they all say the ancient Greeks recognized seven planets.--Pharos 06:24, 18 June 2007 (UTC)

Well, I do have some secondary sources lined up, but unfortunately, the book I'm after is on a 48-hour waiting list. But still, even with secondary sources, I don't think I can ever prove this, not without some work that explicitly mentions the five/seven split (and they are thin on the ground; most books I've read simply take one one conception or the other as a given); so I think the best thing to do, whether I find the right primary sources or not, is to emphasise the ambiguity in the term, rather than make such a formal division (the whole point of this article is, after all, the ambiguity inherent in the word "planet"). That should, I hope, lessen the ORish element in the current draft. Serendipodous 15:41, 18 June 2007 (UTC)

Do you have JSTOR access? I don't have access on my home computer. I'dlike to have a look at this. The online secondary sources are maddening on this; some say seven planets, while others say "The sun, the moon and the planets". It's interesting to note that "ancient greek" "five planets" produces exactly the same number of hits on Google Scholar as "ancient Greek" "seven planets" Serendipodous 16:49, 18 June 2007 (UTC)

Yes, I do have JSTOR access. Here is the most relevant line in that text, speaking of Ptolemy, That he was aware that they offered greater difficulty than the sun and moon is apparent from his reference to them as "the five planets," although it was customary to speak of seven planets. I will gladly send you the full PDF if you e-mail me for it. This is an interesting little note on the Almagest, and the first I've seen that discusses this use of terminology, but I think it's important to recognize that any divergent meaning of "planet" in Ptolemy is more of a colloquial or technical shorthand than a radically different cosmology.

In particular, I don't see any evidence of someone who uses the phrase "five planets" ever disagreeing with someone who uses the phrase "seven planets", and classical authors were certainly quick to point out others' supposed errors. By the way, note that the author on JSTOR says it was "customary to speak of seven planets" at the time of Ptolemy, so I don't see any support for the "five planets first" hypothesis there.--Pharos 00:23, 19 June 2007 (UTC)

Ptolemy was rather late; the Almagest was written in the second century, long after the shift from the Greek to the Roman world. Most of the "seven planet" quotes I've been able to locate are either later, Roman, or both.

The main problem I have with this whole issue is that there doesn't appear to be a way we can resolve it without resorting to OR. We may find a large number of sources mentioning seven planets, but that won't answer the question as to why so many sources refer to five planets. Claiming that it is a colloquial shift is just as much a supposition as claiming it was a different cosmology. Serendipodous 07:38, 19 June 2007 (UTC)

You both make good points and I don't really have a good solution to offer. It could be pointed out, however, that there were recognized differences between the Sun/Moon and the five planets. For example, estimates were made of the distances to the Sun and Moon, but not for the other planets. Also the retrograde motions of the outer planets required the introduction of epicycles by Ptolemy. He used the same mechanism for Venus and Mercury, but locked the centers of the epicycles to the direction of the Sun. So perhaps therein lies some of the differences in interpretation? (His five planets were the wandering stars that employed epicycles.) Otherwise I don't know. — RJH (talk) 15:00, 19 June 2007 (UTC)

One of the secondary sources I've found on this makes the point that the difference between the planets and the Sun and Moon was retrograde. I'll need the source that's currently on hold to back it up, so I won't be able to insert it until Wednesday. Serendipodous 15:25, 19 June 2007 (UTC)

I still think the characterization of the issue is quite problematic. You and I as non-scholars in this field are just not competent to make a comprehensive survey of ancient astronomical writings. We have no authority to make statements about relative preponderances of terminology, nor to make novel observations from primary sources such as that "five planets" precedes "seven planets" (an observation that as far I can tell has not been made anywhere else). The most we can say, in my opinion, is that "seven planets" was customary, but that "five planets" was used sometimes and that the ancient Greeks treated the Sun and Moon differently from the planets in certain ways (without asserting that this is or is not the reason behind terminology differences). When there are virtually no secondary sources on this, I feel we are forced to treat this as academia has treated it, that is largely as a non-issue.--Pharos 02:20, 28 June 2007 (UTC)

I can't really ignore this though; it ties in with the lead sentence for this section: "The word planet has meant many different things in its long life, often simultaneously." EDIT: OK, I've ambiguised it a little more. Serendipodous 07:22, 28 June 2007 (UTC)

Further research on 'five planets' vs. 'seven planets'

OK, I think I've found one secondary source that seems to parallel your influence-of-astrology theory. See Alexander von Humboldt's Cosmos (section starting pg. 297). I also found something interesting on pg. 28 of Studies in Dante, which references George Cornewall Lewis's Survey of the Astronomy of the Ancients (unfortunately not online) to the point that the earlier Greeks had a different ordering of the planets, which placed the Sun and Moon in a separate "zone" closer to the Earth, rather than being separated by the orbits of Mercury and Venus (this change is actually related to the further advance of science, but who knows it may be related to the same gestalt of the influence of astrology).--Pharos 16:04, 28 June 2007 (UTC)

How extraordinary; I had Cosmos on my reading list at the British Library but it got sent back. I knew it referred to the issue but I couldn't find a direct quotation. I've also been trying to locate The History and Practice of Ancient Astronomy by James Evans. Apparently it delves into the issue. It's too late today, but I'll try and get an early morning on this tomorrow. Serendipodous 16:09, 28 June 2007 (UTC)

You do realize you can read Cosmos online, right?--Pharos 16:25, 28 June 2007 (UTC)

Actually, reading it, it was a different Cosmos. Still, the more we can find, the better. And Humboldt is about as cast iron a source as you could hope for. Serendipodous 16:28, 28 June 2007 (UTC)

Shouldn't we source it to Humboldt, then?--Pharos 03:39, 16 July 2007 (UTC)

I haven't had time to work on this yet, but I will be going to the British Library today to track down sources. By all means, source it to Humboldt as well, but I would like to get some more backup. Serendipodous 07:08, 16 July 2007 (UTC)

OK. I've managed to locate a source that, while it doesn't refer to the dichotomy precisely (rather infuriatingly, it refers to Pliny without mentioning that Pliny states there are seven planets), does nonetheless confirm that the Greeks treated the planets differently from the Sun and the Moon. It is: The History and Practice of Ancient Astronomy by James Evans, Oxford University Press 1998, p. 296-7:

The Greeks of the seventh century BC were not even sure how many planets there were. The Greeks had two different names for Venus: it was called Hesperos [evening (star)] in its guise as evening star and Phosphoros (light bringer) when it appeared as morning star. Some asserted that Pythagoras (sixth century BC) was the first to realise that themorning and evening stars were one, while others give the credit to Parmenides (fifth century).

The Greeks considered the planets to be divine, living beings who moved by their own wills. Each planet had a proper name but was also called the star of a certain god:'

Greek name____Translation____Greek god____Roman god

Phainon_________Shiner_________Kronos_______Saturn

Phaethon________Bright one_____Zeus_________Jupiter

Pyroeis_________fiery one______Ares_________Mars

Phospohoros_____light bringer__Aphrodite____Venus

Stilbon_________gleamer________Hermes_______Mercury

...To the early Greeks, the Sun, Moon and fixed stars were far more important than were the planets. The motion of the Sun was intimately connected with the annual cycle of agricultural labors. The phases of the Moon governed the reconing of months. And the heliacal risings and settings of the stars told the time of the year. The irregular and nonrepeating motions of the planets had no such direct utility. So it is not surprising that Hesiod's Works and Days (ca. 650 BC) which contains a good deal of practial lore about the Sun, Moon and stars, makes no mention of the planets.

Serendipodous 19:16, 16 July 2007 (UTC)

There certainly are several sources that point vaguely in this direction, but Humboldt as far as I can tell is the only one to make an explicit statement along such lines. Yes, he is problematic as a source because he is after all "one 19th century scholar", and men of such description have been known to propgate some strange theories. But we shouldn't just gives hints of what we're trying to say, we should say it. And if we say it—barring better, more modern, secondary sources to be discovered—we'll have to rely on old Humboldt to some extent.--Pharos 00:15, 23 July 2007 (UTC)

OK, Humboldt has been added. Thanks for tracking him down. I'd like to think I can finally put this page to rest now but somehow I doubt this will be its final controversy. Serendipodous 12:45, 23 July 2007 (UTC)

Pluto IS a planet, according to the International Astoronomical Union

The whole “Pluto is not a planet” idea comes from reports on the IAU (International Astronomical Union) which got together and decided on a new definition of a planet ["a celestial body that (a) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (b) is in orbit around a star, and is neither a star nor a satellite of a planet”].

From this, it’s been everywhere that Pluto is not a planet. BUT on the IAU’s website, it says that Pluto IS a planet (http://www.iau.org/iau0601_Q_A.435.0.html). Even more, it says there are 12 planets in the solar system, not 9: "Mercury, Venus, Earth, Mars, Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, Charon and 2003 UB313 (provisional name)". The last one is “popularly called Xena,” but the official name has not been chosen yet.

Pluto and Charon are classified as “Plutons,” which is a subcategory of planet, not a separate category. Plus, “Perhaps as many as a dozen or two new planets in the IAU category called “plutons” remain to be discovered” and are just waiting on reports from committees formed to study them.

The whole “Pluto isn’t a planet” might come from the IAU’s attempt to rename everything. They’ve decide that Mercury through Neptune are the first nine planets (planet 1, planet 2, etc), but Pluto is not “planet 9.” Rather, it is “Pluton 1.” —Preceding unsigned comment added by 216.138.96.227 (talk) 18:56, 26 October 2007 (UTC)

That is an old website referring to an earlier proposed definition that did not pass the conference; for the whole bloody story of the different proposals at the time, see 2006 definition of planet.--Pharos 19:06, 26 October 2007 (UTC)

That's the draft resolution. The final resolution excluded pluto. Serendi^podous 19:09, 26 October 2007 (UTC)

The final resolution of August 24, 2006 did indeed include Pluto as a planet. It is clearly stated in Resolution 5A that a planet by the IAU, excluding moons and stars, is spherical by self-gravity and hydrostatic equilibrium. This definitely includes Pluto. It also uses "planet" ambiguously but corrects this in Resolution 5B. The confusion comes from people ignoring 5B. Check the IAU website. It is not old, it is current. Star Guy.

The final definition makes no reference to "Classical" at all. Resolution 5b was proposed, but it failed at the vote. Only 5a and 6a made it through. (see here) If you read the "Semantics" section, not to mention the IAU quote I added two days ago, you can see that the IAU makes perfectly clear that dwarf planets are not planets. I just added the results of the final vote to 2006 definition of planet, so hopefully that should clear the matter up.Serendi^podous 16:20, 2 January 2008 (UTC)

Even before I saw your response I reread both the resolutions and the Q n A page on the IAU site and you're right. The definition does not include Pluto as a planet and as you say in your Semantics section there is ambiguity and this is what is causing the confusion. Sorry about the error. I changed my website accordingly. Would you mind if I included a link for my website, astro-taxonomy.net, which has a clear and broader definition? Star Guy, Jan. 6, 2007. —Preceding unsigned comment added by Bpell (talk • contribs) 09:26, 7 January 2008 (UTC)

I wouldn't mind, but it probably would violate Wikipedia linking guidelines, since it states a very strong point of view. Serendi^podous 23:19, 7 January 2008 (UTC)

That's OK then. But as I'm new to Wikipedia procedures and guidelines I might look into it to make sure. Bpell (talk) 07:10, 9 January 2008 (UTC)

i thought charon was pluto's moon. how then is it a planet? —Preceding unsigned comment added by 69.37.164.205 (talk) 15:32, 23 February 2008 (UTC)

Unlike all other large moons, Charon and Pluto orbit a common centre of mass outside themselves. In essence, they both orbit each other, so either could be described as the other's moon. Because of this, the initial proposal suggested that Charon be considered one part of a "double planet". However, that proposal was dropped and the final proposal left Charon a moon. Serendi^podous 15:59, 23 February 2008 (UTC)

Nice article, inadequate lead

This is a great article, but the lead doesn't do it justice. The current lead reads more like the lead for 2006 definition of planet, and that was what I was expecting to find in the rest of the article. I was (pleasantly) surprised: this article contains a treasure-trove of historical information. However, such surprise runs contrary to WP:LEAD, so I think the lead needs a complete rewrite. Geometry guy 18:50, 1 November 2007 (UTC)

I had a go at editing the lead; I didn't really want to rewrite too much because otherwise I would be in danger of repeating information already in the article. Let me know what you think. Serendi^podous 07:43, 2 November 2007 (UTC)

It is definitely an improvement, but I don't understand why you are concened about "repeating information already in the article": that is exactly what the lead is supposed to do! It should "briefly summarize the most important points covered in an article in such a way that it can stand on its own as a concise version of the article". This means not only that the most important points in the body of the article should be summarized in the lead, but also that "Significant information should not appear in the lead if it is not covered in the remainder of the article". So actually, all the information is repeated! Geometry guy 17:43, 2 November 2007 (UTC)

I just don't see the point of going into too much detail. As long as all the salient points are mentioned, what else needs to be said? Serendi^podous 17:48, 2 November 2007 (UTC)

I agree, and the lead is probably a bit long now: it could surely be made more concise without loss of significant information. To me, it still does read a bit like the lead for 2006 definition of planet, and it repeats itself a few times: for instance the 2005 debate is discussed twice, as is the ambiguity in the meaning of planet historically. Geometry guy 18:35, 2 November 2007 (UTC)

OK; how's that? Serendi^podous 19:01, 2 November 2007 (UTC)

Nice one! Well, I like it, anyway, and hope you haven't found this exchange completely pointless :-) Geometry guy 19:47, 2 November 2007 (UTC)

Nope. Any excuse to edit this article really. I like tending it; it's the only featured article I created, so I like to see it at its best. You know, like a prize winning pet. Serendi^podous 19:55, 2 November 2007 (UTC)

Wikipedia is NOT a dictionary

WP:NOTDICDEF Can somebody explain the significance of this article within the scope of this rule? WP:NOTDICDEF 67.137.0.28 (talk) 04:09, 5 May 2008 (UTC)

This article isn't a definition of planet. It's about the definition of planet. Serendi^podous 05:33, 5 May 2008 (UTC)

It doesn't just define the planet. It explains the definition and presents accompanying viewpoints,etc. I quote: "articles should begin with a definition and description of a subject" --Jagun (talk) 04:42, 30 May 2008 (UTC)

I agree. This article provides a good concise history of planetary astronomy from ancient times to the most modern discoveries, all centered around the central objects of planetary astronomy for over two millennia. This is a good article. And the introduction is excellent. —MiguelMunoz (talk) 23:05, 27 November 2008 (UTC)

Galilean moons

I am moving this comment to the talk page in case I want to figure out a way to reinsert it later. -- Kheider (talk) 15:00, 24 July 2008 (UTC)

Even in the late 1800's astronomers had calculated that the Galilean moons were larger than our own, with one being larger than Mercury.^{(Recreations in Astronomy by Henry White Warren D.D. 1886)}

It could probably go into the double planets section. Serendi^podous 15:13, 24 July 2008 (UTC)

Holy cow

The lead for this article is beautiful. I don't know if I have ever seen prose that great on Wikipedia. Wow. Phenomenal. Matt Yeager ♫ (Talk?) 22:51, 7 November 2008 (UTC)

Thank you :-) Serendi^podous 10:30, 8 November 2008 (UTC)

Use of the word "size"

I changed a description of pluto from "one sixth the size of the Earth's Moon" to "one sixth as massive as the Earth's Moon. The word "size" is tricky, since it can refer to several different properties. We should be careful to use the word "mass" when that's what we're actually talking about. In general, I avoid the word "size" in astronomy, in favor of more specific words like "radius," "diameter," "mass," "length," and so on. This article uses the word "size" a lot, and most of the uses are perfectly legitimate, since it's often making vague (but accurate) claims like "most of these objects were similar in size to Pluto." But for more specific claims, "size" should be avoided. Pluto's diameter is 70% of the Earth's Moon, but it's mass is roughly one sixth. —MiguelMunoz (talk) 22:59, 27 November 2008 (UTC)

Only in our Solar System?

The intro claims that by the end of the 19th century, the working definition "only applied to objects in the Solar System." Strictly speaking, this isn't true. While the known planets were only our solar system, the term was often used when speculating about planets orbiting other stars. In that sense, it applied to undiscovered objects orbiting star. I'm giving some thought to how we might reword that sentence without making it clumsy. —MiguelMunoz (talk) 09:14, 28 November 2008 (UTC)

Definition applies only to our Solar System

Serendipodous: I have two questions:

1) Can you show me the "decree" where this definition applies only to our solar system? The cited reference is vague.

To state that the definition applies here "by decree" misses an important scientific point. If this "decree" exists and if you understood it properly, it exists only because it reflects the state of the current science. It's more important to describe the scientific reasons for the limitation, than to specify the limitation. As it stands, the current definition distinguishes planets from smaller bodies, because that's the only distinction that matters in our solar system. To state that it doesn't apply outside the solar system suggests that other definitions might rival this one, when in fact they complement this one, by distinguishing planets from larger bodies. That's the point I want to get across in this article. —MiguelMunoz (talk) 21:37, 28 November 2008 (UTC)

What you say is your opinion. It is not based on fact or sources. You have not cited any IAU source claiming that your rationale is the one behind the decision. If you're willing to watch the entire 2006 session, you'll see that Owen Gingerich specifically excluded extrasolar planets as too complex to be dealt with then. Serendi^podous 11:40, 29 November 2008 (UTC)

You'll also see that the reason it was too complex was that extra solar planets require that planets be distinguished from larger bodies, which is a very difficult question, whereas the solar system only requires a definition that distinguishes planets from smaller bodies. Owen Gingerich is very clear about this when he is asked why they're not including exoplanets. He answers the question by talking about why they're not addressing the question of "upper limits" of the planet's mass. My source is the same as yours. My point still stands. (Granted, for extrasolar planets, there is the additional question of defining planets in young stellar systems where they haven't had the time to clear their neighborhood, although the science behind the definition may still work, since it could be used to predict which protoplanets have enough mass to do so. But the IAU didn't really go into this, and I didn't want to get into the question of young stellar systems.) —MiguelMunoz (talk) 21:18, 29 November 2008 (UTC)

Serendipodous: I appreciate that you made changes to address the issues I raised here, but you completely removed the point that the new definition is only used in our solar system. I feel that's an important point that should be a part of this article. If you're looking for documentation, check out this clip from the 2006 session. About 60% of the way through, a bearded astronomer (with a thick accent) asks about extrasolar planets, and specifically states that he doesn't want clashing definitions. This is where they clarify that they are only concerned with the lower mass limit, to avoid clashing with the extrasolar astronomers. —MiguelMunoz (talk) 04:39, 30 November 2008 (UTC)

I didn't remove it, I moved it a few paragraphs down. Serendi^podous 21:57, 3 December 2008 (UTC)

2) Why did you also revert my changes regarding the use of the word "size"? Did you even read my discussion post on this question? —MiguelMunoz (talk) 21:37, 28 November 2008 (UTC)

I fixed the mass statement about Pluto since that is more accurate and not misleading. the comment "and with similar orbits" implies that most TNO's have orbits like Pluto, which is not a good general statement. Pluto is a plutino, most TNOs are not. The comment "tend to be much larger than Jupiter" seems to imply that most exo-planets will be larger than Jupiter when the truth is that it is simply easier to detect large bodies. Dwarf planets and asteroids will likely be far more numerous. -- Kheider (talk) 22:12, 28 November 2008 (UTC)

Here's what I meant by "similar orbits," and I think this is an important point that should be in the article in some form. The eight planets all orbit in planes close to the ecliptic, with nearly circular orbits. The NGOs tend to have highly inclined orbits with larger eccentricities. My point was that Pluto's orbit resembles the other NGO orbits. Granted the phrase "similar orbits" is a bit vague. I originally had "similar key orbital characteristics," which was both vague and wordy, and I was reluctant to use terms like eccentricity, since that might go into more detail than the paragraph needs. But my point remains. Pluto's orbit doesn't resemble those of the eight planets, but it does resemble those of most NGOs, and the reasons come directly out of what distinguishes the NGOs from the planets. If you have a better way to put this, then please do so, but it should be in the article. —MiguelMunoz (talk) 23:17, 28 November 2008 (UTC)

Your addition isn't relevant to the definition. The definition distinguishes Pluto purely on the grounds of clearing the neighborhood. That's it. Everything else is just personal opinion. And anyway, not all TNOs have orbits like Pluto (Quaoar has a very circular and flat orbit) and many extrasolar planets have very eccentric and inclined orbits. However, since in that context it doesn't do any harm, I'm willing to keep it. Serendi^podous 11:25, 29 November 2008 (UTC)

As for TNOs tending to be much larger than Jupiter, that sentence was clearly talking about those that have been discovered. Your point about exoplanet detection is well taken, but I feel Serendipodous would have better served our readers by clarifying my point rather than removing it. The reasons I added that phrase come from the points I first raised in this section: The complementary definition's purpose is to distinguish planets from stars.—MiguelMunoz (talk) 23:17, 28 November 2008 (UTC)

Your point, despite being misstated, was out of context in that sentence. That paragraph was about why the IAU had decided not to cover the issue at the 2006 conference. The fact that exoplanets can be larger than Jupiter had nothing to do with it. Serendi^podous 11:18, 29 November 2008 (UTC)

Again, your sources clearly state that the reason this was too complex was that they didn't want to consider the complex question of the upper limit of a planet's mass. So the point wasn't out of context at all. And I don't see how it was "misstated." The fact that exoplanets can be nearly larger enough to be stars had everything to do with it. I put in the size comparison with Jupiter to put the issue in a context that people will be more familiar with. —MiguelMunoz (talk) 21:26, 29 November 2008 (UTC)

I think your problem is not in intention, but in execution. You obviously have problems fully expressing your points on the page, so perhaps it would be best if you kept your ideas on the talkpage. Serendi^podous 21:32, 29 November 2008 (UTC)

And you tell us you're not being territorial? —MiguelMunoz (talk) 01:25, 30 November 2008 (UTC)

This article requires very precise wording, because it must make very fine distinctions. Your additions so far have been vague and unclear, but based on your discussions here you obviously know what you're talking about. So; if you have an addition you think the article needs, offer it up here and, if I think it's valid, I'll try and work it into the article, just as I did for your other two additions. Serendi^podous 01:30, 30 November 2008 (UTC)

"This article requires very precise wording." This is from the one who changed "mass" back to "size." Your suggestion here is hardly within the spirit of Wikipedia. I have no problem with collaboration, and I'm happy to work with you, but your tone here is hardly conducive to a good working relationship. I am not your student, and you are not my supervisor. I will continue to make small changes as I see fit, and if you have a problem with them, please feel free to say so on this page. (Although the article is pretty satisfactory as it stands now.) —MiguelMunoz (talk) 01:57, 30 November 2008 (UTC)

Point taken, though that reversion was accidental. However, I still reserve the right to revert any changes that don't make any sense, unless they are explained on the talk page first. Serendi^podous 10:46, 30 November 2008 (UTC)

Let me reassure you that I have no intention of gutting this article. You and I share the goal of a clear, concise, and accurate article according to the standards of Wikipedia. This is a very good article, and mostly handles the scientific points very well. I wouldn't dream of making any major changes without first getting a consensus of other editors, especially you. There were a few points that I felt weren't as clear as they could be, and I just wanted to clarify them. —MiguelMunoz (talk) 11:26, 30 November 2008 (UTC)

Herschel

You've added that line about Herschel before, and it's been removed, so I don't know why this has come up again. It is inappropriate on several counts. First of all, it is unsourced; second, it uses colloquial emphasis- you make it seem like the narrator is saying, "Aww jeez! It's always a friggin comet!" Finally, it's wrong. The reason Herschel did not suspect that his object could have been another planet was simply because no one had ever found another planet before. It was as alien a concept to him as finding a second Sun would be for us. Other astronomers were actually far more eager to call it a planet than he was. Serendi^podous 11:18, 29 November 2008 (UTC)

It came up again because you removed it with no discussion. And it's not wrong. The statement is factually accurate, which I'm sure you already know, although if you can come up with a counter example, I'm all ears. I wasn't claiming this was a documented part of his thinking, I was putting his discovery in historical context, to clarify his hesitation. His reluctance to call Uranus a planet seems strange to modern readers, so improving the context makes things clearer. —Preceding unsigned comment added by MiguelMunoz (talk • contribs) 19:40, 29 November 2008 (UTC)

OK. I think I understand what you were trying to say, but it was unclear. I can rephrase it, and, more importantly, reference it to make it clearer. Serendi^podous 21:31, 29 November 2008 (UTC)

Your latest addition works pretty well, but I feel it could be strengthened. It's fine to say that "comets were the only moving objects one expected to find in a telescope," but my original point wasn't about expectations, it was about experience. It's a subtle difference, but I feel it's an important one. —MiguelMunoz (talk) 01:45, 30 November 2008 (UTC)

I don't think Herschel's personal experience is relevant. No one had ever observed a planet before, so the fact that Herschel had never observed a planet before is a given. If we were talking about the discovery of Neptune or Pluto, then maybe personal experience would be relevant, but not here.Serendi^podous 10:43, 30 November 2008 (UTC)

I wasn't referring to Herschel's personal experience. I was referring to the experience of all astronomers since antiquity. The preceding sentence described how the notion of the planets had been around since antiquity, which is fine, but it sounds like Herschel was simply treating the prior paradigm with reverence (which he probably was). I felt that it was more important to give the reasons for that reverence, by describing the experience of astronomers since antiquity. —MiguelMunoz (talk) 11:11, 30 November 2008 (UTC)

I don't understand what the difference is. Uranus was spotted through a telescope many times before Herschel identified it, but no one recognised it. The reason experience told people that there was no sixth planet was because no one even considered that one could exist. Serendi^podous 12:26, 30 November 2008 (UTC)

Good question. When I've described Herschel's hesitation to other people, the most common response was incredulity that he called it a comet. It's that misidentification that's so puzzling to people of today. So that's what I wanted to put into historical context. I've tried a few different explanations, but the one that seems to work the best is to point out that, for at least 2000 years before Herschel's discovery, anything new that was ever spotted moving against the stellar background was always a comet. When I put it that way, people seem to have the least trouble understanding it.—MiguelMunoz (talk) 11:48, 1 December 2008 (UTC)

Is that not what the article says now? Serendi^podous 12:06, 1 December 2008 (UTC)

No, it's a bit more vague. It says comets were the only thing "one expected to find." It doesn't say they were the only things that had ever been found. It's close, but it's not as clear. That can be extrapolated from what it says, if you know astronomy. But a beginner wouldn't know enough to make that extrapolation. And we're not writing for the informed reader.—MiguelMunoz (talk) 18:59, 1 December 2008 (UTC)

This is where you and I differ big time. Comets were certainly not the only things that were found through a telescope before Uranus was discovered. Uranus itself was found several times, but was recorded as a star. Galileo even found Neptune once. Its not that these things weren't found; it's that they weren't recognised for what they were. Serendi^podous 19:20, 1 December 2008 (UTC)

Let us not forget the List of Messier objects published in 1771. They merely looked like comets. M1 was first observed in the western world in 1731. Uranus was a 1781 Nebulae/comet. -- Kheider (talk) 19:40, 1 December 2008 (UTC)

I was talking about objects found to be moving, not found through a telescope. It doesn't matter how they were found. And you missed my point about beginners vs. informed readers.—MiguelMunoz (talk) 05:04, 2 December 2008 (UTC)

Well, given the fact that you've had to expend thousands of words explaining what you meant, I don't think your initial addition would have been any help to the novice reader. I couldn't make head or tail of it and I know I'm not alone (when you first posted that line, months ago, someone else reverted it claiming it was incomprehensible). I think the article is fine the way it is; any attempt to say that comets were the only moving objects found before Uranus is just begging to be revised by better-informed historians than either you or me. I've gone out of my way to accomodate your concerns. I would appreciate some reciprocation on your part. Serendi^podous 12:02, 2 December 2008 (UTC)

1) You're hardly an unbiased judge of my communication skills. I was very clear from the beginning that I was talking about objects found "to be moving" and you suddenly started talking about objects found "in a telescope," words I had never used, so it sure looks like you were trying very hard to misunderstand me. This is one of the most territorial remarks you've made here, which is hardly in keeping with Wikipedia's standards. You have also not even answered other questions I've posted on this page, which again isn't in the spirit of Wikipedia. —MiguelMunoz (talk) 22:11, 2 December 2008 (UTC)

2) You say "I've gone out of my way to accomodate your concerns," but you once again didn't address my concern about beginning vs informed readers, even though I've mentioned it twice. Instead you went off on a tangent about objects found through a telescope. You also haven't addressed my objection to your removal of the point that the new definition applies only to our solar system. (see my third comment under "Definition applies only to our Solar System") —MiguelMunoz (talk) 22:11, 2 December 2008 (UTC)

I did address it. I rewrote the entire dwarf planet section to accommodate your issues. Serendi^podous 22:49, 2 December 2008 (UTC)

I posted that comment after you rewrote it. It was a response to your rewrite. —MiguelMunoz (talk) 08:49, 3 December 2008 (UTC)

So I'm assuming that wasn't enough for you. You really aren't keen on meeting people half way, are you? Serendi^podous 11:23, 3 December 2008 (UTC)

I raised a valid point about your change, in the spirit of Wikipedia. You haven't answered my point, so don't tell me that I'm the one that's not cooperating. —MiguelMunoz (talk) 20:55, 3 December 2008 (UTC)

3) You also say ...any attempt to say that comets were the only moving objects found before Uranus is just begging to be revised by better-informed historians than either you or me. If you're questioning my facts, go back and reread your sources. Or give me a counter example. Maybe you're having trouble understanding me because you're not as familiar with the science as I thought. —MiguelMunoz (talk) 22:11, 2 December 2008 (UTC)

What you're asking simply cannot be backed up, because you can't show that NO observer ever saw anything other than a comet when they looked up in the sky. That's proving a negative, which is impossible. How are you going to cite it? Serendi^podous 22:49, 2 December 2008 (UTC)

Well then we don't have to worry about, as you put it, some better-informed historians than either you or me. My point is that, once the seven planets of antiquity were identified, the only new things ever found (and documented) to be moving against the background was always a comet, before Uranus. To this day, the only things that move against the stars are the moon, planets (major and minor), comets, and artificial satellites. If you don't know that to be true, you shouldn't be writing astronomy articles. —MiguelMunoz (talk) 08:49, 3 December 2008 (UTC)

If you don't know that to be true, you shouldn't be writing astronomy articles this is a borderline incivility. To this day, the only things that move against the stars are the moon, planets (major and minor), comets, and artificial satellites—How about natural satellites and Sun? In addition, starts and galaxies also move relative each other. As to you assertion that comets were only moving objects known in the past (except planets, Moon and Sun)), I would say you are wrong here. Meteors had been known for many thousands years before Uranus was discovered. Ruslik (talk) 10:12, 3 December 2008 (UTC)

Meteors were only discovered to be astronomical phenomena in the 19th century by Denison Olmstead. In Herschel's time, they were thought to be an atmospheric phenomenon. (Hence the name "meteor" from the greek for the atmosphere, as in meteorology.) The Sun was one of the original seven planets, and I include satellites with the planets they orbit. Also, I'm talking about movements against the stellar background, not within it. If you'll read my comment in the context of this thread, you'll see that I'm talking about planetary astronomy and 18th century discoveries. The "moving" objects I'm talking about are objects in our solar system. Herschel wasn't going to suspect that Uranus was a meteor or a stellar parallax. As for your allegations of incivility, my point was that Serindipodous knows the astronomy well enough to know that his claim here about counter examples is silly. He knows the astronomy very well. —MiguelMunoz (talk) 20:55, 3 December 2008 (UTC)

One could say that a telescope was inferred since Uranus is at the limit of naked eye visibility and was discovered using a telescope. -- Kheider (talk) 22:43, 2 December 2008 (UTC)

I was referring to anything found before Uranus. For centuries, comets had been found by the naked eye. In Herschel's time, they were also found by telescope. —MiguelMunoz (talk) 08:49, 3 December 2008 (UTC)

By the way, I have an unrelated question about Herschel. You seem to have read more on him than I have, so here goes. Once, many years ago, I read that it was actually Caroline Herschel that first spotted Uranus, but that William got the credit for the discovery by figuring out that it was a planet. However, I haven't been able to find a source for that anywhere. Have you ever read anything about Caroline Herschel's role (if any) in the discovery of Uranus? —MiguelMunoz (talk) 11:48, 1 December 2008 (UTC)

Well, Herschel didn't figure out it was a planet, so I doubt that story is entirely true. I'll look into it. Serendi^podous 12:04, 1 December 2008 (UTC)

Well, I was being brief. He figured out that it had a planetary orbit, and he reported it, which is why he got the credit, according to the story I heard. I wish I knew where I read it. Thanks for checking. —MiguelMunoz (talk) 18:59, 1 December 2008 (UTC)

As a general note

I am sorry if I am coming across as territorial. But this is a very difficult article to maintain, because in a topic like this the difference between fact and opinion is often blurred. However, for this article to be of encyclopedic value it must remain absolutely factual. No unsourced information can be added. No opinions can be stated unless they are the opinions of notable third parties. All facts must be backed up. And I will maintain this standard ruthlessly. Serendi^podous 11:45, 29 November 2008 (UTC)

Your devotion to the facts is admirable, but you don't really need to remove clarifications that come from the same sources you've already cited. I'm very familiar with the issues in the article, having poured over many of the same sources as you. —MiguelMunoz (talk) 21:33, 29 November 2008 (UTC)

Pluto and Ceres

In the section on Pluto, I found this curious sentence: the precedent set by Ceres in downgrading an object from planet to minor planet status because of a shared orbit led many to conclude that Pluto must be reclassified as well. While I was aware that people were calling for Pluto to be reclassified, I am unaware of the precedent set by Ceres playing a significant role in the downgrading. What led to the calls for reclassification were the resemblance of Pluto's size, eccentricity, and inclination to hundreds of other KBOs that had been discovered. I marked this sentence as "citation needed" for now. —MiguelMunoz (talk) 23:16, 1 December 2008 (UTC)

What led to the calls for reclassification were the resemblance of Pluto's size, eccentricity, and inclination to hundreds of other KBOs that had been discovered.

Which was exactly the same reason Ceres was reclassified. Brian Marsden makes the case here. Serendi^podous 00:38, 2 December 2008 (UTC)

Serindipodous: I'm well aware that Ceres was reclassified for the same reason as Pluto, but that's not the question I asked at all. It's the clause "led many to conclude" that I have trouble with. Ceres isn't what led them to conclude that Pluto should be reclassified. It was all the other KBOs that led them to conclude it. The statement in the article certainly isn't supported by that otherwise charming and instructive video, which doesn't say anything about Pluto (and tells me what I already knew). —MiguelMunoz (talk) 03:47, 2 December 2008 (UTC)

That was only a clip. If you want to watch the whole thing, it certainly does make the case. Serendi^podous 11:53, 2 December 2008 (UTC)

Well, thank you for helping me make my case. That extended video says that it was all the other KBOs, not Ceres, that "led many to conclude" that Pluto should be reclassified. Yes, Brian Marsden mentions Ceres in a demonstration clearly aimed at the general public, but do you have articles he wrote to other scientists where he cites the example of Ceres? All the other scientists in the video make their case by talking only about the other KBOs. The whole show is telling us that it's all the other KBOs that led them to reclassify Pluto. Can you show me where Marsden (or anybody else) makes the case to other scientists by talking about Ceres? —MiguelMunoz (talk) 20:52, 2 December 2008 (UTC)

What does whether he mentions this to other scientists have to do with it? This isn't a scientific issue; it's not going to be resolved by a scientific paper. Serendi^podous 21:08, 2 December 2008 (UTC)

When he's making a case to other scientists, he just gives his reasons. When he makes a case to the public, he also puts it in the proper historical context, which lay readers aren't likely to be familiar with. This is more than a scientific issue, but it is a scientific issue. Also, Marsden is only a single scientist. The sentence in question states that the precedent of Ceres "led many to conclude..." which isn't supported by the sources cited. So there are two problems with the sentence.—MiguelMunoz (talk) 22:37, 2 December 2008 (UTC)

I propose changing the sentence to this: Many scientists concluded that tiny Pluto should be reclassified as a minor planet, just as Ceres had been, a century earlier. This conveys the same information, and confirms the connection with Ceres, but without the inaccuracies of the earlier sentence. It's more in line with what the cited sources are actually saying.

Fair enough. Changed. Serendi^podous 11:21, 3 December 2008 (UTC)