Talk:Clearing the neighbourhood

(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)[reply]

Was that TIC? Jim62sch 21:02, 24 August 2006 (UTC)[reply]

Just plain wrong

This article is a serious misunderstanding of the term. I don't even know where to begin. It probably doesn't even belong here. I wish people would at least make an attempt to read the primary sources before creating stuff.Derek Balsam 21:05, 24 August 2006 (UTC)[reply]

The term means to clear all objects from an orbit, either by taking it as a moon, colliding with it, or slingshotting it out of the orbit.

It properly refers to the history and end-state of the dynamic process of accretion over time from the original planetary disk.

This definition is questioned by the fact that Neptune is still classified as a planet, despite the existence or Trans-Neptunian objects such as Pluto.

Not questioned by anybody with any scientific knowledge. Neptune is the end state of an accretion process in its orbital region. Trans-Neptunian objects are, well, beyond Neptune.

It is possible that Neptune's orbit only overlaps with Pluto's in two places, and that is why Neptune is considered a planet.

Neptune's orbit does not "overlap" with Pluto's at any point. This is well known, not merely "possible".Derek Balsam 21:11, 24 August 2006 (UTC)[reply]

I wiped this and replaced it with a newer stub; it's still wrong (because I'm not entirely clear on this myself - slept through too many lectures) but it's a lot closer to right. Isn't there a better term for this, anyway? "Orbital dominance"? Shimgray | talk | 21:17, 24 August 2006 (UTC)[reply]

I don't remember what the technical term is either but "clear the neighborhood" is the term used in the popular press at least. If someone can locate a more technical term we should consider moving this to that and making this a redirect or making that a redirect to this with a note about what the technical term is. JoshuaZ 21:21, 24 August 2006 (UTC)[reply]

I've given a link to an excellent paper by Steven Soter on the subject, and which uses the term. I guess technically you might call it many things, for example dynamic dominance, or as Soter does, "tendency of disk evolution in a mature system to produce a small number of relatively large bodies (planets) in non-intersecting or resonant orbits, which prevent collisions between them."Derek Balsam 21:26, 24 August 2006 (UTC)[reply]

I think someone might beat us up if we move the page to that, though... Shimgray | talk | 21:27, 24 August 2006 (UTC)[reply]

tendency of disk evolution in a mature system to produce a small number of relatively large bodies (planets) in non-intersecting or resonant orbits, which prevent collisions between them Go for it! LOL Derek Balsam 21:32, 24 August 2006 (UTC)[reply]

It looks way better than it did...but you're right, it's still not totally accurate. It'll get there though. I'm not 100% sold on the argument regarding "clearing the neighborhood" simple because the eccentricity of its orbit takes it inside Neptune's orbit. The real question should be, given the obliquity of Pluto's orbit could it ever get close enough to Neptune to be cleared out of Neptune's orbit? Anyway, there are also problems with Pluto's gravitational pull as Charon and Pluto orbit each other with the focus of their orbits relative to each other being in the space between them. OK, I'm rambling. Sorry. Jim62sch 22:24, 24 August 2006 (UTC)[reply]

Hmmm. The concept of dominating an orbit is pretty solid science, and so is the answer to your question about Pluto and Neptune's orbits. Pluto and all the other plutinos are now stabilized in an orbital resonance determined by Neptune, the dominant body. So the answer to your question " given the obliquity of Pluto's orbit could it ever get close enough to Neptune to be cleared out of Neptune's orbit?" is, "not any more, because over the last few billion years the plutinos have fallen into resonance with Neptune as it came to dominate its orbital domain".Derek Balsam 01:15, 25 August 2006 (UTC)[reply]

Doesn't make sense to me

By this definition, does it not mean that a planet cannot have any satellites? /confused. --Djedi 22:07, 24 August 2006 (UTC)[reply]

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)[reply]

And how does Pluto not meet this definition?--Djedi 02:46, 25 August 2006 (UTC)[reply]

Quite simple, Pluto has many other objects in its orbital domain, notably all the plutinos.Derek Balsam 02:50, 25 August 2006 (UTC)[reply]

what about planetary rings, such as saturn's? if so that should be included.

Proposed merge

This term is just casual (poorly defined) working of the recent decision about Dwarf planets. Until it is better defined (it it becomes better defined), it should be left in the context of the subject it relates to. Thee is nothing here that woudl not go better in teh various articles about orbital dynamics and physics. Dalf | Talk 23:26, 24 August 2006 (UTC)[reply]

I disagree (and have reverted a merge made without any discussion). Whilst the term has suddenly come into prominence from that debate, it has a seperate meaning... In addition, why to "dwarf planet" specifically? The ruling pertains as much to planets, or to definition of a planet, and so forth - it doesn't obviously fit with just one page. Shimgray | talk |

Oppose merge, for Shimgray's stated reasons. Clearing the neighborhood refers to planetary disk accretion and orbital dynamics in general, not just for dwarf planets. A merger to Dwarf planet would be too specific. Maybe to Planetary orbit, though... Derek Balsam 01:10, 25 August 2006 (UTC)[reply]

Support merge, but to Definition of planet. I think that whole article probably needs to be overhauled now anyway, and it should explain each of the criteria in the new definition, including this one. This information has already been put into both Planet and Dwarf planet in summary form, but the detailed information should be in Definition of planet. I do not think there needs to be a separate article. Plus someone who is not into astronomy might look at this title and think the article is about Urban renewal. 6SJ7 01:16, 25 August 2006 (UTC)[reply]

Oppose merge too, as stated above this term is in the mouth of everyone following the recent astronomical developments. It would be nice to somehow add some astronomical reference to the title or quotes, becasue "clearing the neighbourhood" can be just a mudane expression.Dr. Guillermo A. Sanz-Berney 03:45, 25 August 2006 (UTC)[reply]

A final definition of this term will be very helpful. It should be a sub article of "Definition of Planet". For example, by some definitions Earth has done a better job clearing its orbit than Jupiter. Jupiter has Trojan Asteroid in substantial quantities. Ergo, it could be said that it hasn't "cleared it's neighborhood" and should be downgraded with Pluto. This is an important discussion, but should be a sub article of Definition of Planet, and/or Dwarf Planet. 70.177.71.206 04:21, 25 August 2006 (UTC)[reply]