Talk:Clearing the neighbourhood/Archive 1

message: (UTC)Pluto is automatically disqualified because its oblong orbit overlaps with Neptune's. (AP)
:But what about Neptune? Should not it be disqualified as well? ST47 20:59, 24 August 2006 (UTC)
replies: text: Was that TIC? •Jim62sch• 21:02, 24 August 2006 (UTC)
thread_title: Pluto & Neptune

message: My understanding of this clearing business is this
Neighbourhood of a point is a set containing the point where you can "wiggle" or "move" the point a bit without leaving the set. (from Wiki)
This neighbourhood is trem used in Topology. We can define it in simple words as
The neighbourhood of size Theta around a point P is the set of all points whose distance from P is less than Theta.This can be extended to: the neighbourhood of size Theta around a set of points S (such as an orbit) is the union of the neighbourhoods of size Theta around each point of S.
Now the problem is, we need a parameter and measurement for this neighbour hood. Then all confusion will over. In this senario we know that the parameter is km. But how much wherther it is 100 or 1000 or 10000km .  The number of planets depends on the size of this neighbourhood. If the size of neighbourhood is large then almost all planets especially Jupiter, Mars and Neptune will be Dwarf Planets. So what we need now is an explanation from Astophysicts about  this Neighbourhood.
:The term is well defined. See reference 2 of the main article http://arxiv.org/abs/astro-ph/0608359 In that document an orbital zone is defined as follows: "Two bodies share an orbital zone if their orbits cross a common radial distance from the primary, and their non-resonant periods differ by less than an order of magnitude.", which is a pretty simply definition of neighborhood. I would add that the current neighborhood is to a first approximation the torus traced out by the orbital path of the planet's Roche sphere. For better approximations you need to consider all the Lagrangian points as well. But that's really saying the same thing:  non-resonant, non-crossing orbits.Derek Balsam 14:40, 28 August 2006 (UTC)
replies: text: The order of magnitude part doesn't affect any interesting cases (except maybe Sedna), so this is essentially equivalent to saying that two bodies share an orbital zone if their orbits cross.  Which is contrived, since the definition is allegedly based on the idea that the planet has gravitationally influenced nearby objects, and gravitational influence happens when two objects are close by, regardless of whether their orbits cross.  Specifying that the orbits cross seems more like an arbitrary attempt to exclude Pluto than to actually do what the definition is supposed to do. Ken Arromdee 07:53, 3 September 2006 (UTC)
replies: text: None of this has any bearing on the article.  If you object to the "demotion" of Pluto, I would suggest you correspond with the International Astronomical Union and explain to them why they are wrong.  •Jim62sch• 13:14, 3 September 2006 (UTC)
thread_title:  What is this neighbourhood 

message: By this definition, does it not mean that a planet cannot have any satellites?  
/confused. --Djedi 22:07, 24 August 2006 (UTC)
replies: text: Think of it this way: it has cleared its orbit of anything that's not under its direct influence.  Anything left in the orbit has either collided with it (and become part of it), been pulled into orbit around it (as a moon), or left in a synchronous orbit (like a plutino or a trojan asteroid).  The planet is the end result of the orbit clearing that has gone on for billions of years.  Contrast the main asteroid belt.  It has not been cleared except in the Kirkwood gaps (by Jupiter).Derek Balsam 22:14, 24 August 2006 (UTC)
replies: text:  And how does Pluto not meet this definition?--Djedi 02:46, 25 August 2006 (UTC)
replies: text: Quite simple, Pluto has many other objects in its orbital domain, notably all the plutinos.Derek Balsam 02:50, 25 August 2006 (UTC)
replies: text: My understanding of these things sucks, but looking at the plutino page seems to show they have different, yet similar orbits.  So, I'm guessing I'm just misinterpretting, but to me for the clearing bit would that not mean you have the real potential to collide at some time in the future to be considered in the same orbit?Derekloffin 04:56, 25 August 2006 (UTC)
replies: text: Remember, we're talking about objects in the *orbital domain* not necessarily the exact orbital path. Pluto is one of many very similar objects all orbiting in very similar orbits. If all of those orbits were governed by Pluto's gravity, then Pluto would be a planet. Instead, all of those orbits, including Pluto's orbit, is governed by the gravity of Neptune, so Pluto is not a planet in itself, but essentially an accessory body to Neptune...vaguely similar to the situation with Jupiter and the Trojan asteroids. --Aelffin 15:44, 25 August 2006 (UTC)

text: Planetary rings are essentially just big smushed-up moons, they don't invalidate the concept. Shimgray | talk | 08:18, 25 August 2006 (UTC)
replies: text: In fact they explicitly support the concept.  They are in orbit around the planet, and being in orbit means that Saturn has cleared it's neighbourhood as "capture" is one of the three means of so doing.  •Jim62sch• 12:44, 26 August 2006 (UTC)

text: Soter's definition of the term is unambiguous; "Two bodies are defined to share an orbital zone if their orbits cross a common radial distance from the primary, and their non-resonant periods differ by less than an order of magnitude." The version used by IAU hasn't been made explicit yet but since they got results similar to Soter I expect it's something similar. Bryan 15:56, 31 August 2006 (UTC)
thread_title:  Doesn't make sense to me 

message: Couldn't "clearing the neighbourhood" also refer to tough, righteous, vigilante types such as The Punisher who clear their neighbourhoods of pimps, hustlers, and other scum? I think we should make this clear in the lead. Marskell 07:58, 25 August 2006 (UTC)
thread_title:  Other uses 

message: I removed a comment about how the Earth, Mars, Jupiter and Neptune (and who knows what else) are now "dwarf planets".  This is flat nonsense on its face, so the editor will need to come back with a seriously good, incontrovertible, reference before inclusion can be entertained.  I am sorely tempted to remove the remaining paragraphs.  While referenced, they are nothing more than a commentary on the recent IAU definition:  we already have an article on that one, and those comments would probably be better placed there.  mdf 15:52, 25 August 2006 (UTC)
replies: text: It's amazing what people interpret this as meaning. I really wish they'd used a much more complex term for it, one which didn't have an "obvious" (and wrong) interpretation... Shimgray | talk | 16:02, 25 August 2006 (UTC)
replies: text: I agree with the last comment and would also say that, as a non-scientist who likes to read about science, I am very surprised at the informal manner in which this was done and the informal and undefined language in which it was expressed.  I have learned to expect a high degree of precision in scientific pronouncements; these resolutions are really political documents more than anything else.  Rather than approve a scientific paper, they have adopted something more like what I would expect from my state legislature (and that isn't good.)  As a result, the collective effort by Wikipedians to express what has happened is, predictably, chaotic and unscientific as well.  6SJ7 16:47, 25 August 2006 (UTC)
replies: text: This new definition was supposed to get rid of the ambiguity that plagued the old definition, but it did just the opposite.   Now, with terms like “neighbourhood” and “nearly round”, it’s more confusing than ever.  Really disappointing. 206.47.141.21 17:58, 25 August 2006 (UTC)
replies: text: "Nearly round" isn't the definition - it's an explanation of the definition for laymen. Hydrostatic equilibrium, the words immediately preceding it in the resolution, is perfectly clear if technical. Shimgray | talk | 18:01, 25 August 2006 (UTC)

text: " Is the orbit of Mercury clean because of the gravitational interaction of the planet, or for the much greater force derived by the proximity of Sun?" um, yes, both. See Roche sphere. It would be helpful to understand astrophysics to properly contribute to an article on that subject.Derek Balsam 22:04, 25 August 2006 (UTC)

text: Or maybe you can read a book on solar system dynamics?  The definition as written is perfectly fine.  Mercury is Mercury because of how it formed and where it is, and Pluto is Pluto for the same reason.  Move Mercury out to 50AU and, la dee da, it will stop acting like a planet!  The IAU definition is dynamical, and this is because dynamical processes created it, and dynamical processes maintain it.  mdf 21:35, 25 August 2006 (UTC)
thread_title:  New IAU definition, interpretations and conclusions 

message: Despite what I've heard on other science talk pages, this seems to be yet another case of scientific consensus being determined by voting. --Uncle Ed 20:25, 25 August 2006 (UTC)
replies: text: No, this is applied politics.  makes clear that this is a conflict between the planetary geologists on one side and the celestial mechanics on the other. Dr Zak 05:00, 26 August 2006 (UTC)
replies: text: Thanks for clarifying that. I would hate go off leaping to conclusions. I always look for patterns, being a Generalist, but 'false links' are embarrassing. ;-) --Uncle Ed 13:10, 26 August 2006 (UTC)
thread_title:  Science and voting 

message: Did Saturn "clear the neighbourhood"? After all, the planet has massive, and visible, rings. If Jupiter had done it's job, Saturn wouldn't exist, and neither would the rings. Seems to me the IAU messed it all up. 206.156.242.36 20:39, 25 August 2006 (UTC)
replies: text: ok this whole debate on scientist messing up, or a conspiracy theory is just a waiste of important editing time... don't you think? before the resolution nobody argued the validity of IAU's prerogative to define planet. When the result was not what expected disenter jump yelling FOUL!! Let's just say Pluto is not a planet anymore because Rove decided it had WMD and was a terrorist cell. DrCito 21:41, 25 August 2006 (UTC)
replies: text: Re Saturn, the rings prove the validity of the concept as the capture of objects is one of the three ways a planetary body clears its orbit.  The comment about Jupiter simply makes no sense. •Jim62sch• 13:17, 26 August 2006 (UTC)
replies: text: I agree with you re: Saturn. I do think the very statement is a value judgement and not a metric despite some miguided soul at the IAU having come up with it. Just how does one define the term "clear the neighbourhood" in any meaningful measurable way? Robovski 01:18, 27 August 2006 (UTC)

text: The term is subjective in that the definition of neighbourhood is somewhat arbitrary -- yes, there is a value picked to determine neighbourhood, but like it's like the measurement of a quart: yep, it's 32 ouces, or 64 tablespoons, or 4 cups, etc, but the ounce is an arbitrary measurement -- a bit bigger or smaller and the volume of a quart changes.  In other words, I agree with you.  •Jim62sch• 22:18, 27 August 2006 (UTC)
thread_title:  On "Clearing the neighbourhood" 

message: Personally I don't care if the spelling is US, Canadian, UK, or whatever.  But lowercase second and subsequent words!  Derek Balsam 03:09, 26 August 2006 (UTC)
replies: text: Seconded. This isn't a proper name, as far as I can tell, so shouldn't be capitalized. Bryan 03:10, 26 August 2006 (UTC)
replies: text: I wrote what's below first, and had an edit conflict and had to move my comments to this page. Whoever decided to change to the British spelling without discussing it apparently doesn't know about the capitalization conventions on Wikipedia. (And should perhaps practice better the convention of discussing the issue, which I raised in my edit summary on 2006 redefinition of planet.) -DoctorW 03:18, 26 August 2006 (UTC)
thread_title:  Article title 

message: I realize this is a very small issue, especially given this page's problems, but why is the word "Neighborhood" capitalized in the title of this article? Shouldn't "Clearing the Neighborhood" redirect to "Clearing the neighborhood" instead? This becomes a bit more of a problem because there is also an issue of U.S. vs. British English in the spelling. I just had to fix the same link's redirect twice. -DoctorW 03:18, 26 August 2006 (UTC)
replies: text: I think the spelling should be British. Though the article cites American astronomers, the phrase is becoming famous in relation to Pluto, and the IAU statement uses the spelling "neighbourhood."(See RESOLUTION 5A) -DoctorW 03:31, 26 August 2006 (UTC)

text: Another for commonwealth english Nbound 05:30, 28 August 2006 (UTC)
thread_title: "Clearing the Neighborhood" vs. "Clearing the neighborhood"

message: Should List of solar system objects by planetary discriminant be merged with Clearing the neighbourhood ? --Sonjaaa 11:50, 26 August 2006 (UTC)
replies: text: I think it will end up being merged with Definition of planet, which is its parent article. We just have to decide whether to keep all info about the definition of "clearing" here or there. --Uncle Ed 13:08, 26 August 2006 (UTC)
replies: text: Which would be fine, but I'd rather see the issues the article has weorked out here first. •Jim62sch• 13:18, 26 August 2006 (UTC)

text: I think this article could be specifically reorganized around the concept of orbital mass dominance, and everything that deals more generally with "clearing the neighborhood" could be moved to the Definition of planet article. Dancter 13:37, 26 August 2006 (UTC)

text: The article "Definition of planet" is already rather large, I think we should keep at least one separate article where this orbital dominance/clearing concept is described in detail. Especially considering we don't have the IAU's take on exactly what it means yet, just Soter's - they'll probably be quite similar but there could be some fiddly bits that are different. What title it'll be best put under, and whether to merge that list into it, I'm not sure. I'd prefer to let the articles evolve for a while longer before coming to an opinion. Bryan 16:35, 26 August 2006 (UTC)
replies: text: I'm just concerned that we're conflating the "clearing the neighborhood" issue with Soter's concept too much. Especially with the controversies, the comments by Stern and others seem to refer specifically the phrase in the IAU resolution text, and don't seem to address the particulars of Soter's essay at all. Dancter 22:21, 26 August 2006 (UTC)
thread_title: Merge?

message: Pretty interesting that Earth is technically no longer a planet. Preeeetty inteeerestinnng... 'FLaRN' (talk) 21:39, 26 August 2006 (UTC)
replies: text: Er, no. Earth is technically and obviously a planet. "Clearing its orbit" does not mean what you apparently think it to mean, and indeed what everyone else posting the same comment seems to think it means... hmm, perhaps that's indicative. Are we failing to explain this correctly? Do we need a "Popular misinterpretation" section, or would that be OR? Shimgray | talk | 21:45, 26 August 2006 (UTC)
replies: text: Such a section might very well be OR.  In any case, I refer Flarn to Near-Earth asteroid. •Jim62sch• 22:24, 27 August 2006 (UTC)
thread_title:  Earth 

message: From the current version of Definition of planet:
It may not be entirely clear what "clearing its neighborhood" actually means. Alan Stern recently objected that “it is impossible and contrived to put a dividing line between dwarf planets and planets,” and that since neither Earth, Mars, Jupiter, nor Neptune have entirely cleared their regions of debris, none could properly be considered planets under the IAU definition. () This would appear to contradict his earlier published work: “we define an überplanet as a planetary body in orbit around a star that is dynamically important enough to have cleared its neighboring planetesimals ... And we define an unterplanet as one that has not been able to do so,” and then a few paragraphs later, “our solar system clearly contains 8 überplanets and a far larger number of unterplanets, the largest of which are Pluto and Ceres.” (“Regarding the Criteria for Planethood and Proposed Planetary Classification Schemes,” S. Alan Stern and Harold F. Levison, Oct.-Nov. 2000)
As you can see, Stern & Levison's paper, or some version of it, is available on the web, albeit as a postscript file.  This paper may actually be the original source of the IAU paraphrase "clearing the neighborhood."  If so, summarizing the debate continues to be a challenge, since Alan Stern is one of the main players on both sides. 67.168.216.176 16:56, 3 September 2006 (UTC)
replies: text: Well, I think the appropriate thing to do is to quote and cite him freely on both sides of the argument and simply make sure we point out that it's the same guy (the dates on the cites will also be of particular importance to get right). Unless he or someone else has published something since then that actually invalidates that paper, the maths still say the same thing regardless of what the guy who wrote them down now believes. I must say though, on a personal note, that although I knew this planet definition debate was bound to get silly I never expected this sort of silliness. :) Bryan 17:44, 3 September 2006 (UTC)
thread_title:  Origin of the phrase, and what to do about Stern 

message: From http://adsabs.harvard.edu/abs/2002HiA....12..205S
Title:	
	Regarding the criteria for planethood and proposed planetary classification schemes
Authors:
	Stern, S. Alan; Levison, Harold F.
Publication:	
	In: Highlights of Astronomy, Vol. 12, as presented at the XXIVth General Assembly of the IAU - 2000 [Manchester, UK, 7 - 18 August 2000]. Edited by H. Rickman. San Francisco, CA: Astronomical Society of the Pacific, , 2002, p. 205 - 213
Publication Date:	
	00/2002
Origin:	
	ARI
Keywords:	
	Planets, Classification
Abstract Copyright:	
	IAU
Comment:	
	JD4: The transneptunian population. Eds.: A. Lemaître; H. Rickman; C. Froeschlé.
Bibliographic Code:	
	2002HiA....12..205S
Abstract:
We examine the question of planetary classification, making recommendations both for the criteria by which planethood should be evaluated, as well as for more detailed physical and dynamical subtype classification schemes.
And from the paper itself at http://www.boulder.swri.edu/~hal/PS/planet_def.ps:
Regarding the Criteria for Planethood And Proposed Planetary Classification Schemes
S. Alan Stern and Harold F. Levison
09 Pages, 02 Figures, 02 Tables
Submitted to the Transactions of IAU 2000: 04 October 2000
Revised: 11 November 2000
Running Title: Planet Classification: Gravity Rules
Abstract:
We examine the question of planetary classification, making recommendations both for the criteria by which planethood should be evaluated, as well as for more detailed physical and dynamical subtyle classification schemes.
The existing Wikipedia citation looks something like this:
* 
How this document, maybe the central source material for the whole subject, should be footnoted exactly is not an area of expertise of mine.  We have two different years and a number of different months to choose from, but I think these references are all to the same thing. Since it's possible to link to the actual document, probably we should. Maybe like this?
* 
67.168.216.176 03:19, 4 September 2006 (UTC)
thread_title:  Dates on citations etc. 

message: shouldn't this be "orbital dominance" or something? 132.205.44.134 02:54, 4 September 2006 (UTC)
thread_title:  title 

message: I disagree with the proposed split. The term "planetary discriminant" is used by Soter only to refer to the "μ" parameter that he calculated by dividing the mass of the object by the total mass of the other objects in its planetary zone, it doesn't refer to the "Λ" parameter proposed by the Stern-Levison paper. The section's content is currently about an even mixture of the two and I don't think there's so much of it that it warrants removing from this article. Bryan 03:31, 8 September 2006 (UTC)
replies: text: Okay, so maybe it's pulled from two articles, and maybe some of this information belongs here, but It's kinda out of place to have all the math here when that's not the crux of the topic. I think it's a way good point, but the math belongs elsewhere. I think the perfect article could be written on Planetary discriminants. McKay 03:57, 8 September 2006 (UTC)
replies: text: The information in that section makes up the bulk of the article removing it would make a somewhat useless article that really only goes into the controversy. I disagree with the split -- Nbound 04:06, 8 September 2006 (UTC)

text: There's a single equation, I don't see this as excessive. But even if it was a lot of math, why doesn't math belong here if it's math about neighbourhood-clearing? I'm afraid I still don't see the reason why this should be split out of here. Bryan 05:01, 8 September 2006 (UTC)
replies: text: REally, my argument to make them seperate articles, is that they are seperate topics. Interelated sure, but seperate nontheless. McKay 13:45, 8 September 2006 (UTC)
replies: text: But they're not. Stern and Levison's work was all about determining a theoretical estimate of how quickly a planet could clear its neighbourhood of other objects, Soter's work was all about determining an experimental measure of how thoroughly a planet already had cleared its neighborhood. That is exactly the topic of this article. I'm afraid I just don't understand your position. Bryan 00:00, 9 September 2006 (UTC)
replies: text: Im with Bryan on this... -- Nbound 00:55, 9 September 2006 (UTC)

text:  Let me be clear. I think the planetary discriminants should be here. The table is acceptable. But how those numbers are calculated isn't really a part of Clearing the neighborhood. It's a part of planetary discriminant. The planetary discriminants themselves are a part of the article. McKay 03:06, 9 September 2006 (UTC)
replies: text: ...Sorry, still completely boggled. I can't figure out what the distinction is here, or why the results of calculating planetary discriminants is okay but describing the process of how those results are achieved is not. Heck, I've even been considering merging List of solar system objects by planetary discriminant into this article as well. I think we may have to simply agree to disagree on this matter, unless someone else can chime in and support splitting in some way I understand. Bryan 04:01, 9 September 2006 (UTC)

text: After reviewing the arguments, and re-reading the "clearing the neighbourhood" article, I am in favor of the split.  In addition the resultant article should in truth be 3 articles, 1 for each of the 2 values ( "μ" , "Λ" ) and 1 specifically cover various planetary discriminants.  Should any other values arise they to should have there own articles and be covered in the planetary discriminates article breifly.  As for list of any kind, they should be separate articles both link to and from related articles. Abyssoft 14:27, 11 September 2006 (UTC)
replies: text: I have no objection to articles specifically on those particular parameters existing and although I don't like the idea of separate list articles in this case it's no skin off my back if they exist too. What I don't get is why that information shouldn't be here, since they're on the topic of this article and the article is not overly large. You've stated your opinion on the matter but you haven't explained any of the reasons for it so I'm not left with any better understanding of this position. Why do you think this information should be removed from this article? Bryan 16:00, 11 September 2006 (UTC)
replies: text: Rather then out right removal, I am refering to a brief synopsis of the information, with approriate links to the complete articles.  This is simply a matter of proper organization.  Lists while informative in terms of data tend to muddy a page and can detract from the meat of the article; hence why such lists should and are generally found on separate pages through out the wikipedia.  The planetary discriminate article should be about, what is a planetary discrimate, its conception and history, and briefly touch on the various values, like ( "μ" , "Λ" ).  By briefly a quick simple formula and what it represents; Leaving the background of the value to it's own article. Abyssoft 17:36, 11 September 2006 (UTC)
replies: text: I agree with Bryan.  This information is being presented by non-experts based on the best sources we can find, and the presence of examples can serve to crystalize understanding where a block of awkwardly presented text may just be incomprehensible.  You can look at the table and see yeah, Ceres and Pluto are different from the others, look at all the names and numbers together.  Also remember this is already a "separate article," even a sub-sub-article.  The main articles are probably Pluto and Planet. 67.168.216.176 02:27, 12 September 2006 (UTC)
thread_title:  Proposed "planetary discriminant" section split

message: This is Dwheeler citing himself as a source.
Not that I necessarily have a problem with that, but still ... 67.168.216.176 04:47, 8 September 2006 (UTC)
replies: text: it has been done (not by me) McKay 13:45, 8 September 2006 (UTC)
thread_title:  Just in case nobody else noticed 

message: “clear the neighborhoods around their orbits,” means that anything that is under its direct influence has either collided with it, or has been pulled into orbit around it, thats what it means right? so pluto isn't a planet because it orbit through stuff, right?
:Not quite.  "Clearing the neighborhood" means being the dominate mass in the vicinity of the orbit.  So Jupiter outweighs the Trojan asteroids, Earth outweighs the near-Earth asteroids, but Pluto does not outweigh Neptune. Michaelbusch 22:12, 8 October 2006 (UTC)
thread_title:  I'm still confused 

message: Some one want to archive some of this? Michaelbusch 22:12, 8 October 2006 (UTC)
replies: text: The talk page is less than two months old and is only 64K large so I'd suggest not archiving yet unless the size becomes truly unmanagable. Bryan 22:38, 8 October 2006 (UTC)
thread_title: Archive?