Talk:Solar System/Archive 1

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Pluto's size

The table satates that Pluto has a diameter of 0.24 times Earth, while the Pluto (planet) page states that it is only of 0.18 (which is concordant with my own data). The masses also differ but in opposite direction: the table of the article says it's 0.0017 Earths and the Pluto page says it's 0.0021.

I noticed because, comparing the two tables, Pluto seems a lot larger than Sedna or Quaoar, when Quaoar and Ixion are commonly accepted to be about half the size of Pluto and Sedna only slightly smaller than Pluto (estimates).

Would somebody more knowledgeable than myself take a look at Pluto's figures and fix them with authority?

Vandalism

If anyone really wants the vandalism I deleted they can look on the revision page.

Pluto

So it's official? Pluto is not a planet anymore? I know that there has been quite a bit of contraversy about it. I didn't know that the issue was mostly settled in the astronomical community. -- ansible

"officially," Pluto is a planet. It is also a Trans-Neptunian object, a Plutino, and a Kuiper belt object. Ultimately the only solid criteria for planethood is "what we point to and call 'a planet'," and by that criteria Pluto is unlikely to lose its status as a planet any time soon. By the time it does, nobody will care (by definition :).

BTW, I checked with Dave Jewitt of UH (author of the Plutino external link) and Pluto is NOT a Plutino -- a Plutino is something in a similar orbit but smaller than Pluto itself. Joelwest 04:54, 24 Mar 2004 (UTC)

picky detail, just to remind contributors: this is a criterion, not criteria, since it is singular. (Just like phenomenon/phenomena.) Now, if you'll excuse me, I'm going for lunch in the cafeterion...

as for its location in the list on this page, there isn't a subheading specifically for "planets" so I wouldn't take Pluto's position as being significant.

The controversy over Pluto being a "planet" really belongs on the Pluto page, so the wording has been changed to point to it. As for the substance, some say it never was a "major planet" and should be considered the largest of the "minor planets" which would include things like Sedna (astronomical object) Joelwest 19:19, 20 Mar 2004 (UTC)

Cruithne

Before I swap this, is there any reason Cruithne is listed before the Moon, in the table? Vicki Rosenzweig

Fact tables

I would like to prepose that the planet articles be re-deisgned and have a table to the right giving basic details eg number of satelites(moons), mass, rotation speeed. etc and more detailed info to the left. - fonzy

There already is such a table at Earth for example. But please don't stretch yourself too thin -- you already have several tables you started on Temp on other pages that still need to be filled-out. What works for me is that I take things one step at a time and make sure I do a thorough job. --mav

I like the idea of a more standardized table than the current collection of facts in bulleted lists that most planets and moons have. I'll start working on a template over at Solar system/Factsheet template. Bryan Derksen 18:19 Aug 16, 2002 (PDT)

Solar System vs Solar system

Since this is about the solar system (proper noun) shouldn't it be at Solar System and then solar system can be about solar systems in general? --mav

Hm. I always thought it was the Solar system, since it's named after Sol, and other systems would be "the Rigel system", "the Sirius system", etc. and the general term was "star systems". But I've got nothing to give particular weight to that approach. Bryan

Fair enough. --mav

Hmm. If the name of the system was named after "Sol" in the same way that the Rigel system is named after Rigel, then it would be the "Sol system", not the "Solar system". But anyway, the Oxford English Dictionary says that the English word "solar" comes from the Latin adjective solar (I'm not sure if that should have an ending because I've forgotten most of my Latin). That's related to the Latin word sol, which means "Sun" in Latin, but that's not the same as saying that the astronomers took the name of the system from the name of the name of the star directly. It seems that the link goes back to the days before the English language even existed. But anyway, the Oxford English Dictionary actually has the "solar system" with lower case letters. So should we go with them? Then again, it also spells "sun" with a lower-case "s". I didn't expect that. Hmm... I think I'll just leave it for now. -- Oliver P. 08:47 12 Jul 2003 (UTC)

One can imagine, as non-astronomers became more interested in the planets around our star and then around other stars, how the phrase "solar system" would be pressed into use for these others as well. Science fiction, which had reason to make distinctions early on, has used varieties like "star system" and "stellar system". I always thought "stellar system" made the most sense as a generic version, as it follows the form of "solar system". I'm disappointed that it hasn't displaced the ambiguous use of the latter phrase. -- Jeff Q 13:27, 10 Jun 2004 (UTC)

Is there any way of conclusively determining which it is? If not, can we agree on one? Even within the article itself, capitalisation is fairly random, and it'd be good to standardise on something IMO, even if it's only by vote or whatnot. (Also, is it Solar System vs. Solar system vs. solar system?) -- Wisq 13:51, 2005 May 18 (UTC)

The name should be "solar system", the only reason "Solar" is capitalised is that all article names are capitalised in by the Wiki software. "Solar" is not the sun's name, "solar" is French (imported from Latin) and means "of the sun" so "solar system" literaly means "system of the sun", just like "solar radiation" means "radiation of the sun", "solar diety" means "diety of the sun" and so on. Sun should not be capitalised either, unlike for the Moon, sun is not the official name of our star (it has none!). While the sun is officialy unnamed I prefeer to use the name "Sol" (wich solar is dirived from), it was the name given to the sun by the Romans it somehow just didn't "stick" the same way the names they gave the planets did (probably because people have always refeered to "the sun" while the planets where unknown before they where named anyway so there was no existing terms for the "new" planet names to contend with). That's another debate though (see the "Termonology" section further down the page). --Sherool 08:09, 22 July 2005 (UTC)

Is this where we're discussing the proposed move (from "Solar system" to "Solar System")? If so, I oppose as well. Although it may change as we become familiar with extrasolar systems, currently usage is lower case, much as we still refer to our star and satellite as "the sun" and "the moon" most of the time (although increasing familiarity with other suns and moons changes that in certain circumstances). See Merriam-Webster, the Encyclopædia Britannica, and Encarta for examples of other reference works which use a lowercase "solar system" (which should be lowercased throughout the article as well). — Knowledge Seeker দ 08:56, 22 July 2005 (UTC)

I also oppose the proposed move from "Solar system" to "Solar System". I think that "Solar system" in the text would be adequate, although currently the usage "Solar System" is what's in the text. Personally, I prefer the usage "Solar system" to both "solar system" (use "planetary system" for the common-noun case) and "Solar System". I'd rather see List of solar system objects and List of solar system objects by mass moved to "List of Solar system objects", etc. --Eric Forste 20:52, 22 July 2005 (UTC)

The capitalization of "Solar" in the middle of the names of articles like "List of Solar system objects" is unnecessary. We are indeed talking about a particular planetary system, but we are not saying "the Sol system". Words such as "solar" and "lunar" are not capitalized. Furthermore, the term "solar system" almost always refers to our planetary system, unless there is some modifying phrase to make it clear that the term is being used as a synonym of "planetary system". The term "solar system" should be written in lower case.

On a related note, the guideline I've always followed for "Sun" versus "sun" is that if our particular star is being discussed in an astronomical context, it should be capitalized ("The Sun is a medium-size yellow star" as opposed to "Plants absorb light from the sun"). The subject of "Earth" versus "earth" uses a slightly different criterion: if "Earth" alone is being used as a name for our planet in an astronomical context, as opposed to "the earth", it should be capitalized ("Earth revolves around the Sun in about 365 days" as opposed to "Three-quarters of the earth is covered in water"; but note "Ants can be found almost everywhere on earth", where the focus of the sentence is not on Earth as a celestial body). —Bkell 21:21, 9 August 2005 (UTC)

Surface

The bit on surface area seems confusing. How may the surface area of the objects of the solar system be accurately found? Even a single planet, say the Earth. It is not a perfect sphere, it's a fractal. Just like it is not possible to find the length of the coastline of Britain, it is not possible to find the surface area of the Earth. You can start by saying that the Earth is a sphere and measure its area, and then zoom in on a tall mountain, that mountain is, say, in a shape of a cone, and you correct your first measurement with this new detail in mind. But then you zoom in even further to discover other mountains and that mountains aren't really cones and that the landscape is so wrinkly, no one can be sure of its area. You can actually zoom in infinitely. Ah, you get the idea. I, therefore, disagree with the value and the possibility of finding an accurate value, without a suitable restriction, for a surface of a physical, non-classical mathematical object, such as may be found in the solar system. Might I add that the referenced article was written by a geographer, who does not include references to other works, nor an indication of how he was able to come up with the values. Evgeni Sergeev 01:57 18 Jul 2003 (UTC)

I think Wikipedia can follow the conventions and practices of geography, and ignore the fractal issues unless there's evidence that they are significantly more important on other solar system bodies than they are on earth.

We don't make a habit of including error bars, or disclaimers about fractals, in the areas in geography articles, and I don't think we should start.Vicki Rosenzweig 02:02 18 Jul 2003 (UTC)

I think we should. Geography needs a bit of a shake-up. But I'm not editing the article, because it is everyone's encyclopeadia, not just mine. But the fractal matter seems pretty important to me anyway. Evgeni Sergeev 02:31 18 Jul 2003 (UTC)

We should indicate when something is an estimate. Pizza Puzzle

For a start, shapes of planets are not true fractals, they're scale-limited. It gets boring at <1nm. But the usual way to calculate surface areas of such things is to smooth them out at a scale much greater than 1nm. I suspect that from the perfect sphere approximation, down to ~1km resolution, surface area doesn't change very much. Hence, the choice of scale is not as arbitrary as it might at first seem -- a sphere is a good enough approximation for practical purposes. As for indicating when something is an estimate: well, all the figures we give are estimates. Perhaps it would be good to indicate when something is a particularly poor estimate (e.g. worse than +/- 30%). -- Tim Starling 02:54 18 Jul 2003 (UTC)

The fact that we are smoothing out the surface is significant. Now it makes sense. An area measurement like this would be knowledge of some value: eg. to calculate how much energy does the Earth receive from the Sun. I read the source and corrected the statement: this is the surface area of solid objects only. Now, the fractal nature of planets: do we really know that they are boring and non-self-repeating at small scales? That seems to me the limits of our knowledge, not the limits of scale. Yes, there is an upper scale limit. But doesn't the Mandelbrot Set have an upper scale limit? I thought I read somewhere that it wasn't a true fractal, but you still couldn't calculate the length of its borderline. Anyway, at small scales, the whole concept of surface area is shadowy: what is the surface area of an atom, if it is mostly space inside? Hmm... the present value for surface area is fair enough. Evgeni Sergeev 02:28 19 Jul 2003 (UTC)

The surface area of an atom can be defined by arbitrarily picking an electron density to draw the line at. Chemists do the same thing to calculate volumes. Quantum mechanics gives systems of electrons a characteristic scale: the Bohr radius. According to QM, there is no fine detail below this scale. There is ample experimental evidence to back this up.

Sometimes you hear things like "this object is 99.99999999% empty space". That's not really true -- under standard QM, it's 100% empty space. A definition by electron density, rather than by the amount of non-existent "extended" matter, restores the common sense definition of volume. -- Tim Starling 10:00 19 Jul 2003 (UTC)

By approximating all solar system bodies as spheres, you avoid one fractal problem. But, there is another: there is a huge amount of surface area of dust and grains in the Solar System. The source from U. Texas explicitly gives a lower cutoff of 1km. I'll put that in, also. -- hike395 04:41 19 Jul 2003 (UTC)

By the way, the amount of energy the Earth receives from the Sun is not related to its surface area; it's proportional to the solid angle it cuts out of the sphere of radiating energy from the Sun. Even when you calculate energy per square meter of the Earth's surface, what you're really doing is determining the solid angle formed by an ideal square meter of surface with the Sun in a specific position in the sky and distance from the Earth. None of these quantities can be considered precise or constant enough to worry about fractal scales. -- Jeff Q 13:51, 10 Jun 2004 (UTC)

Navigation footers

Nephelin has updated the footers for all Solar system related pages. I like the light cyan box. However, I disagree with some of the additional links. I believe that one of asteroid or asteroid belt should be removed from the list, because they are redundant. I would suggest keeping asteroid, because it is a more developed article. I also would like to remove planet and star, since they are generic articles (hypernyms of objects in the Solar system). Comments? -- hike395 20:27, 25 Jan 2004 (UTC)

The first line contains only the astronomical objects of the solar system (heliocentric view), the second line contains the transneptunal objects and general astronomical objects. And sorry, asteroids are not equal with the asteroid belt! Nephelin 21:13, 25 Jan 2004 (UTC)

Here's the problem: there are many solar-system related articles. What criterion should be used to include them in the box? Should we include Near-Earth asteroids? How about Alinda asteroids? Or Quaoar? Or zodiacal light?

To me, highlighting in a box or footer suggests an overall navigation aid, rather than an exhaustive list of topics. I believe that an overall navigation aid should list just the planets, plus perhaps asteroid. IMO, more links than that makes the navigational aid less useful for novice astronomy people.

If you'd like to make a separate page of Solar system topics and create a more complete list, I would be in favor of that. -- hike395 05:28, 26 Jan 2004 (UTC)

The current footer has Kuiper belt, Oort cloud and Trans-Neptunian object, but Kuiper belt and Oort cloud are both subsets of Trans-Neptunian objects. I'd suggest either getting rid of TNOs, or getting rid of Kuiper and Oort. Also, I agree that "planet" and "star" don't really belong in a navigation bar like this; they're too generic. Perhaps a link to moons would be a good replacement? That way, all the major bodies of the solar system are no more than two clicks away. Bryan 06:51, 26 Jan 2004 (UTC)

Planet and Star are too generic... but Moons are not? I agree with Kuiper belt and Oort clound to replace them by Trans-Neptunian object. And Asteroid and Comet could be replaced by Astronomical objects. But the Asteroid belt is a part of our solar system among the sun and the planets (an the Trans-Neptunian objects). A suggestion:

Nephelin 07:22, 26 Jan 2004 (UTC)

The table is left aligned by mozilla though the align attribute of the table tag is set to center... Why? Is this another mozilla bug or a feature?! Nephelin 09:00, 26 Jan 2004 (UTC)

the "align" attribute is not a legal part of the <table> tag in HTML 4.01, see [1]. Mozilla obeys the official specs for HTML a lot more closely than other popular browsers (*cough*IE*cough* :), so what you're seeing isn't actually a bug in Mozilla - it's correct behavior, and the bug is in the other browsers that show the table centered. :) I found a short discussion on this page on how to center tables "properly": [2]. I've taken the liberty of implementing it by adding style="margin-left:auto; margin-right:auto; text-align: center;" to your table above, and it seems to work on Mozilla here. Hope it works on other browsers too. :) Bryan 01:07, 27 Jan 2004 (UTC)

"Moon" is no more generic than "asteroid" or "trans-Neptunian object", IMO. If there were a specific "moons of the solar system" article that dealt only with moons in our solar system rather than moons in general I would have suggested that instead, but the current "natural satellite" article fills that role right now. As for the changes to the asteroid links, I just finished adding a huge listing of asteroid groups to the asteroid article and am currently pondering splitting it off into a separate asteroid group article to reduce the clutter in the main article. I was going to sleep on it, but since this is Wikipedia who knows what the situation will be in the morning. :) You may want to have a look at that listing to see if there are any other ways of dividing up the minor planets; for example, you could throw in Centaurs to fill in the gap between asteroid belt and TNOs and then all the major populations of minor planet would be covered. Bryan 07:37, 26 Jan 2004 (UTC)

You know, this discussion illustrated something for me. I suspect we need both a List of solar system objects (a hierarchical page) in addition toAstronomical objects (planet,moon,star,galaxy, etc.) This would allow a sophisticated user (college graduate, e.g.) to navigate. I think we should aim the footer at schoolkids. So, how about for the footer, listing the nine planets plus List of solar system objects? We can have a see also for Astronomical objects.

I guess we could leave off both asteroid belt and asteroid from the footer, if we're going to write a nice hierarchical solar system object page. (Asteroid belt started out as a stub written by Bryan, and grew up independently from asteroid. Asteroid is far meatier. Should we fold asteroid belt back into asteroid? It feels so redundant.) -- hike395 04:53, 27 Jan 2004 (UTC)

Asteroid belt could be turned into an article on the Main belt fairly easily, I think, which is a topic reasonably far removed from plain old generic asteroids to maintain its independance. As for a list of solar system objects, there's an outline of such objects over on solar system that I created a while back that may make a good start for a more detailed list. Mix in the list of asteroid groups I recently completed on asteroid, and I can't think of any class of matter in the solar system that is omitted. (otherwise I would have included it in one of those lists already :) Bryan 05:21, 27 Jan 2004 (UTC)

Actually, as I look at it, I'm not sure asteroid belt needs any changing. The subject it covers is broader than just the main belt. Bryan 05:27, 27 Jan 2004 (UTC)

OK --- we don't have to fold asteroid belt. I agree that your taxonomy is pretty good. A few questions lurk for a prospective article: should we make an exhaustive list of moons? Or just the largeish ones? Ditto for asteroids?

natural satellite has a table with what seems to be an exhaustive list of the moons, grouped by planet and by size ranges. List of asteroids in our Solar System has a list of large and/or noteworthy asteroids that have articles in Wikipedia (I know of at least one with an article that isn't in here, 141 Lumen) but an exhaustive list may not be a good idea - there are over 10,000 minor planets known, IIRC, and the number's growing by hundreds every year. :) Perhaps simply linking to these articles from the main list will suffice? Bryan 07:50, 27 Jan 2004 (UTC)

I made a first cut at a List of solar system objects. I would propose that the footer should read:

---Sidenote START---

Comments? -- hike395 07:56, 28 Jan 2004 (UTC)

Looks good. Just tweaked the style to center it, though. :) Bryan 08:16, 28 Jan 2004 (UTC)

I slept on it and thought it was too verbose. Cut the extra words out of the See also list, since the article titles are self-explanatory. See above. If everyone likes it, I'll implement sometime soon. -- hike395 03:29, 29 Jan 2004 (UTC)

Yeah, that one's more compact without losing anything. Gets my vote. Bryan 04:15, 29 Jan 2004 (UTC)

I think asteroids are too generic. the region between mars and jupiter is called main belt or asteroid belt - but not asteroids. both, solar system objects and astronomical objects matches asteroid... there are asteroids outside the solar system! the context of the quick-nav is solar system - it's a pity that you cannot reach transneptunian-objects or kuiper belt/oort cloud directly anymore. the reason for a quick-nav about solar system is to quick navigate between solar system objects - like one-click-buy on amazon - and not three or two clicks or one more list (the "See also" is for a nav-bar obsolete imho)... Nephelin 07:42, 29 Jan 2004 (UTC)

I'm thinking of this list something for high school students. I'm betting that they don't often need quick one-click access to TNOs, so they get to be hidden inside List of solar system objects, where the undergraduate and graduate students will look.

As for asteroids vs asteroid belt: My main motivation is that the asteroids article is a lot more complete than asteroid belt. Further logic: Notice that all of the other entries on the first line are objects, asteroids are objects, too. No one has detected an asteroid outside of the solar system, so I doubt if people will be confused by that. One possible compromise is that we could use asteroid belt (pointing to the asteroid article), but that is kind of inelegant.

Re: see also. Obsolete? I'm not sure what you mean. I can drop it, but I wanted to indicate that other stuff that you don't see on the list above is hidden in these following articles. I can expand it to say "For other objects and regions, see:" ... More verbose, but clearer.

---Sidenote START---

The Solar System
Sun | Mercury | Venus | Earth | Mars | Asteroid Belt | Jupiter | Saturn | Uranus | Neptune | Pluto
For other objects and regions, see: List of solar system objects | Astronomical objects

--hike395 16:36, 29 Jan 2004 (UTC)

Updated Sun,Mercury (planet),Venus (planet),Earth,Mars (planet),Asteroid,Asteroid Belt,Jupiter (planet),Saturn (planet),Uranus (planet),Neptune (planet),Pluto (planet),Asteroid moon,Centaur (planetoid),Comet,Cubewano,Kuiper belt,Natural satellite,Planetary ring,Plutino,Scattered disk object,Solar system,Trans-Neptunian object,Trojan asteroid,Zodiacal light,Quaoar to use the above footer -- hike395 05:00, 31 Jan 2004 (UTC)

I have just copied this table over to MediaWiki:Solar system. To place a copy of it on a page, one now simply has to type {{msg:Solar_system}} and it will magically appear. The underscore is necessary, it seems. Bryan 01:41, 16 Feb 2004 (UTC) (note: deleted that particular page since the one below got used instead. Bryan 07:58, 16 Feb 2004 (UTC))

Really cool! Thanks!!! -- hike395

No problem. If you want, I can do the work of switching the existing footers over to the msg version instead; that way if we decide to change the footer in the future, all of the articles will change automatically to reflect it. Bryan 02:16, 16 Feb 2004 (UTC)

Looks like Timwi changed them all over, but to yet another different footer :-(. I prefer the footer that we built by consensus here. I copied our consensus footer over to Template:Solar System. I'm happy to continue the discussion over at MediaWiki talk:Solar System. -- hike395

Shouldn't the footer be entitled 'The Solar System', as it appears in this page? The actual one in the pages say 'Our Solar System', even though nobody else has a solar system but us.

It seems redundant to list both Pluto and the Kuiper belt. If we're going to name one of them, wouldn't we have to name all 800? -Arctic.gnome 20:37, 23 November 2005 (UTC)

Overlap with Asteroid Entry

This lists the Solar System as having 7 types of objects, from the Sun to dust. Meanwhile, the asteroid entry subsumes comets, Centaurs and TNOs as types of asteroids. There seems to be some disagreement (whether among astronomers or just in common English usage) as to whether asteroid subsumes all planetoids or just the rocky ones or just the ones in the asteroid belt.

That said, this section heavily overlaps and contradicts the asteroid entry. This appears more authoritative (e.g. a clean distinction within the TNOs) but that doesn't guarantee it's right. The contradictions need to be straightened out (preferrably by someone with real knowledge) and the definitions should be only in one place. Joelwest 19:42, 20 Mar 2004 (UTC)

When I did the asteroid groups I got all the information from [3], which uses the title "Minor planet groups/families." Minor planet looks like a broader term than asteroid, but currently minor planet simply redirects to asteroid. Perhaps a separate article is in order. Bryan 22:13, 20 Mar 2004 (UTC)

I'm not sure that yet another article is needed. One possibility is to drop the comets, Centaur,s and TNOs from the asteroid article, which makes it simpler and clearer. Bottom line: I'm agreeing with Joelwest. -- hike395 02:46, 21 Mar 2004 (UTC)

I wouldn't want to just delete the beyond-Jupiter groups, though, since it lists more categories and details than is present in other Wikipedia articles on the subject. I'd prefer to move it somewhere. How about using minor planet for listing all of the various groups of minor planet currently at the asteroid article, turning it into a sort of huge disambiguation page? Bryan 05:17, 21 Mar 2004 (UTC)

Yes, I see --- I made a poor assumption about duplication. A huge minor planet page may be OK. --- hike395 06:39, 21 Mar 2004 (UTC)

Done, how's it look? Bryan 07:51, 21 Mar 2004 (UTC)

This is really neat --- asteroid is a lot crisper and easier to read. --hike395 17:35, 21 Mar 2004 (UTC)

Solar system model name

Does anyone know the Greek or Latin neologism for a mobile-like 3D model of the solar system? I can't quite recall it, and search engines suggest that people typically just call them "solar system models". Since virtual solar system apps are called the same thing, it's useful to know the specific word for the physical model. -- Jeff Q 14:00, 10 Jun 2004 (UTC)

I believe it would be an "orrery". Apparently named after Charles Boyle, 4th Earl of Orrery, who had one made for him, rather than Greek or Latin. -- Curps 14:26, 10 Jun 2004 (UTC)

Already an article at Orrery, so perhaps Solar system model could disambig. -- hike395 14:31, 10 Jun 2004 (UTC)

Well, that explains why I couldn't remember it! Greek or Latin, indeed. ☺ I went ahead a made Solar system model a redirect for Orrery, until somebody decides to expand upon the generic concept of "solar system model". Thanks a bunch! -- Jeff Q 19:49, 10 Jun 2004 (UTC)

---

I just fixed the solar system model table. I feel it should be moved into a separate article so it can include more information about the models and links to model homepages where they exist. (e.g. mos.org) I would use Solar system model. Any objections or comments? --agr 01:44, 26 Dec 2004 (UTC)

Minor Planet Table Reorganized

I've altered the minor planet table and added an introduction. I hope I don't step on anyone's toes with this. I changed the order of the data in the minor planet table so that it matches that of the major planet table: starting with the inner bodies and working outward. The minor planet bodies were previously arranged by number only.

Probes in Solar System

Does anyone know why it is almost impossible for probes visiting planets beyond Earth to return? Is it because of some unknown force that pulls the probe forward? Why is it easy for probes going to planets in front of Earth to return? Is this unknown force pulling the probes forward into the Earth? Could it be that this force is pulling probes visiting planets beyond Earth forward and farther and farther away from Earth? Why isn't there another force that goes the other way around?

What probes do you have in mind? I'm not aware of any probes that have gone to other planets and returned. Worldtraveller 17:23, 16 Apr 2005 (UTC)

No spacecraft has gone beyond Moon and returned to Earth's surface (well, Stardust and Hayabusa are going to return some samples from a comet and an asteroid, respectively; and let's not forget Genesis probe which collected solar wind particles. Of these, only Hayabusa is actually going to land). But to land on another planet, and then return to Earth (for example, Mars sample return mission) is very hard to carry out. Reason? They must get to the target planet, collect some samples, launch the sample back to space (the fuel must be carried all the way on the planet) and then return to Earth. That means more massive and complex spacecraft, which means larger launch vehicles, which in turn means more costly missions. On the other hand, Earth has been frequently used as a gravitational slingshot for probes going elsewhere (for example Galileo and Cassini-Huygens probes have visited Earth's vicinity since they left Earth), because to conduct a flyby you don't need much fuel to change your speed and direction. That's why they're so handy.--Jyril 17:59, Apr 16, 2005 (UTC)

The Edge of the Solar System

I was wondering if there could be a debate about what constitutes the "edge" of the Solar System. You still hear in the media that the Voyagers and the Pioneers have "left" the Solar System, when it is difficult to claim that they have. But what *is* the edge of the Solar System? The heliopause? The Oort Cloud? Could there be anything beyond that?

Well, the Voyagers at least have certainly left the orbital plane of the system, which would suggest they've 'left the system'. But yes, it's ambiguous, as far as I can see. -- Wisq 20:56, 2005 May 25 (UTC)

Yes, they've left the ecliptic, but the Oort Cloud is not on the ecliptic, it surrounds the Solar System like a shell, does it not? If so, then no matter where these probes are headed, they still have to pass through the Oort Cloud. 157.140.6.143 14:05, 27 May 2005 (UTC)

Sedna=10th Planet?

I have heard that recently, a group of scienctists have annouced plans for making an Oort Cloud object known as Sedna the 10th planet of our Solar System. For those who don't know, Sedna is an object that is about half the size of Pluto and has one single moon. Now, about the distance it is from the Sun. Let's say the distance Pluto is from the Sun is A. Now multiply A by 10. The result is the distance Sedna is from the Sun. Sedna has caused a lot of disputes about whether Pluto and Sedna should be considered planets. Some people say that Pluto or even Sedna in the matter are too small to be considered planets. Personally, I think that Pluto should be considered a planet and not Sedna. Sedna is named after the Inuit goddess of the sea. I would like to hear any questions or comments you have about this discussion.

I don't think that many scientists seriously consider Sedna as a planet. It's way too small and most likely not unique. Pluto, if it was found today, wouldn't be called a planet either. However, it was originally defined as such and we have had nine planets in our Solar System for over 70 years, so IAU defines it still as a planet. If trans-Neptunian objects larger than Pluto are found its planethood may be abolished. But this is only a matter of definition, border between a planet and a minor object is arbitrary. (FYI, Sedna is not an Oort Cloud object, although it orbits extremely distant, it is too close to visit even the inner Oort Cloud. Secondly, Sedna has no moons, large at least.) --Jyril 11:16, July 10, 2005 (UTC)

Trans Neptunian object bigger than Pluto. Check. See section on the newly discovered 2003UB313 below. --Sherool 09:31, 30 July 2005 (UTC)

I just want people reading this to be clear that Sedna and 2003 UB₃₁₃ are different objects. See Planet X for all the other objects that have been called "the 10th planet." -Hyad 22:50, July 30, 2005 (UTC)

Terminology points

I originally removed mention of 'sol system' because it's a very uncommon usage, as far as I can tell only in sci-fi novels. Therefore, to consider it an alternative name for the solar system is overstating the case a great deal. I really don't see the need, in an article about a real physical phenomenon, to mention what science fiction writers call it in fictional works.

Another point of terminology is the use of 'mesoplanet'. The article on it says it was a term coined by Isaac Asimov. I am an astronomer and had never heard of it. The exclusively used term for objects larger than asteroids but smaller than planets is planetoid: mesoplanet is not mentioned at all in the astronomical literature [4].

My general point is that in scientific articles we should be using scientific terminology, not science fiction terminology. Therefore, I'm in favour of not mentioning 'sol system', and using the word planetoid which is favoured by the astronomical community. Worldtraveller 23:15, 16 July 2005 (UTC)

I beg to differ on the matter of "Sol". Scientific terminology is fine and dandy, but scientists will never use "Sol sytem" because they're stuck in the current context. In SF, speculation about the space-faring future is "de rigueur", and as a result one has to come up with some name for "the solar system". This is etymology in the making; when we eventually become a space-faring species, we will refer to the Sun system by some label, and my feeling is Sol is gonna stick, if only because SF authors have claimed the advance ground on the issue.

In any case, I do not see the throwaway mention of "Sol system" as detracting from the article. Does anyone else feel one way or the other?

Urhixidur 03:21, 2005 July 17 (UTC)

I think the current version is best in its elegancy and with the link to article sol which explains the logic and the context. I did a quick google search on "sol system" and while most hits were scifi related (games, literature etc.), the term was occasionally used by laymans discussing space and science. "Sol system" had also found its way to a newsletter of the orange county astronomers and to a NASA www-page - The Merciful 13:37, 17 July 2005 (UTC)

I don't think we are in the business of taking part in etymology in the making - that seems to border on original research and being a dictionary function. If 'sol system' becomes common, we should report that, but it's very uncommon at the moment so I don't see the need to promote its use. Scientific usage already deals with the situation of distinguishing this from other planetary systems, referring to here as 'The' Solar System and other systems as planetary systems, eg [5]. I think using sci-fi terminology so prominently does detract from an article about a scientific subject. In terms of google hits, solar system gets over 12 million while sol system gets less than 50,000. Worldtraveller 13:54, 17 July 2005 (UTC)

This borders on the perverse: Should Wikipedia only reluctantly report facts and knowledge once it « becomes common »? Obviously not. Encyclopediae are the place of choice to find obscure facts and knowledge. Stating things are so does not constitute promotion. If the article started with something like « The Solar System, more correctly called Sol system... », that would be (undue) promotion.

Urhixidur 12:12, 2005 July 20 (UTC)

"Earth" has section about goverment and several specific mentions of its use in scifi, article about planet Venus has mythological and scifi references, Lagrange point 3 is mentioned as "a popular place to put a "Counter-Earth" in pulp science fiction and comic books". In my opinion these kind of references make articles to have wider and more complete usefulness. Seems to me is a good thing, especially in a hyperlinked whole such as Wikipedia. Mentioning one scifi term in "solar system" article seems a small "offence" in comparison. Is there an official policy or a style guideline about this, or is it a matter of personal taste?

Besides, mentions of "Sol" or "Sol system" have been in the article a few times before, and will likely pop-up in future. I think having some reference (whatever it will be) to "Sol" or "Sol system" would put an end to this. - The Merciful 19:41, 17 July 2005 (UTC)

Sol is not a sience fiction term. I've seen several NASA articles and astronomy sites using the term "Sol system" to establish context (granted they probably use "the solar system" more often often). The only reason it's more common in sience fiction than in real sience is the fact that up untill a couple of years ago sinece only knew about one (our own) solar system, so there was not much need to disambiguate). The name "Sol" for the sun goes back thousands of years though, and "sol" translates to "sun" from at least a dozen different languages (including my own native language so I guess I might be somewhat biased). Most notably from Latin wich is pretty much the "language of sience" when it comes to naming things, clearly the name has quite a bit of history and it's not just something sience fiction writers made up. It might not be common in English and it's not an official name (none exist), but it's the closest thing we have at the moment. As more and more extrasolar planets are discovered the need to actualy attach a "propper" name to our own system will only increase with time, and "Sol system" seems like the only likely candidate (better than making up a completely new name anyway). --Sherool 15:49, 19 July 2005 (UTC)

I'm afraid I disagree on several points here. The general public and astronomers almost exclusively use the term 'solar system'. As far as 'sol system' goes, google gives less than 50,000 hits for it, while Solar System gets 12,000,000, so Solar System is used 99.5% of the time. On NASA sites, 'Sol System' gets 6 hits, while "Solar System" gets 209,000, so NASA use of Sol System is vanishingly rare. While the word Sol itself is of course very old and exists in many languages, the English word is Sun, and this is the term we should use. 'Official' astronomical nomenclature does exist and is defined by the IAU, which uses neither Sol or Solar System. As far as disambiguating goes, external planetary systems have been known for over a decade, and there are approaching 150 of them so far discovered, but as Solar System refers by definition specifically to our Sun, no disambiguation problems arise. Other systems are known as, for example, the Tau Ceti system or the 51 Peg system or similar. If Sol System becomes an accepted term for the Solar System then that should be reflected here, but it is not, so I don't see why the term needs to be mentioned here. To me it seems a bit like saying "The British Isles, also known as Airstrip One".

As there is some disagreement about this and related subjects, perhaps we should seek comment from the wider community? Worldtraveller 16:21, 19 July 2005 (UTC)

Heh, for me it's the other way arond, using "Solar System" seems to me a bit like refeering to the Earth simply as "the world". Although when I think about it all the objects "early humans" would be likely to consider "one of a kind" (the sun, the earth and the moon) seem to simply use the localized generic term as a "propper" name. As far as I know none of those objects have a "internationaly" recognized name (Sol/Helios, Tellus/Terra/Gaia) and Luna/Selene have been used in ancient times (AFAIK), but again they are basicaly just Latin or Greek translations of the generic terms anway, and whre only "internationalised" because those nations had a lot of influence in theyr heyday), might as well call it the Sun system then I guess :P

As for requesting comment. Might be interesting to get the input of a couple of more Wikipedians, though I'm happy to accept any consensus (or lack thereof) we reach on this page and elsewhere it's beeing discussed. The only reason I'm being so "vocal" right now is that I happen to be in favour of the Latin names (mostly because I find the lack of a "universal" name for such things to be "messy") and felt "my" side was somewhat under-represented (or beeing written of as obscure sci-fi cruft). I can live quite happlily with the status quo. I just want to make sure "my" side of the issue is covered. --Sherool 17:41, 19 July 2005 (UTC)

If you're taking a poll, here's my two cents worth. I've been an amateur astronomer for about twenty-five years and I've read many, many astronomy and planetary science articles and books during that time. In my experience, the term "Sol" is rare and "Sol system" is very rare in both scientific literature and popular science writing, though it has been common in science fiction usage for decades. I believe the term "Solar System" means "the planetary system of Sol" and is already very well established in both scientific and everyday English usage. So, in this case, my personal opinion is that it's not necessary to refer to the Sun as Sol in this article since it is mentioned in the Sun article anyway. However, I find that I really have no very strong feelings about it either way - particularly since the article will most likely be edited hundreds of times in the future anyway. --DannyZ 00:48, 20 July 2005 (UTC)

I'm an Astronomy magazine and Sky & Telescope columnist, and I'll throw in my two cents for what it is worth. I can't find the term "mesoplanet" in either magazine's index. I've never heard an astronomer use the term. I'd never encountered it until I read this discussion page and had no idea what it meant. To me, that argues strongly against using the term in an article about science, especially since a genuine scientific term found in the literature (including "my" magazines) with a widely understood meaning (planetoid) is available that is used to describe the same concept.

Sol system should not be used for the reasons already given, and others. Sol is a term used to describe secular phenomena on planets other than earth (e.g., the length of a 'day' on Mars). A sol system is in this context a convention for local planetary timekeeping - not a reference to a planetary system. Several of the NASA references to sol systems reflect this meaning. The other references I've found are the ejaculations of PR writers rather than specialists, probably influenced by scifi. In any case, sol system is not used by any astronomer or astronomy writer that I know of to designate this planetary system - the term solar system is used instead.

In the scientific literature, "solar system" refers to this planetary system, not generically to stars surrounded by planets. Other plantary systems are referred to as "extrasolar" (e.g., Google on "extrasolar planet") or by their system name as already mentioned.

In order to communicate concepts cogently, an encyclopedia needs to conform to the standard usage and special terminology of in the fields it reports on. Therefore, Wikipedia needs to use astronomical terminology to describe astronomical topics. --Jeff Medkeff | Talk 03:44, August 4, 2005 (UTC)

Misuse of the word "planetoid" to mean something other than "minor planet"

(moved from User:Worldtraveller)

Does "planetoid" actually mean what you are using it to mean on the Solar system article? --Arkuat 06:15, 2005 July 17 (UTC)

It does - a planetoid generally means a body smaller than the main nine planets but large enough to be spherical. Like the definition of planet, it's arbitrary, and the article currently arbitrarily states that Ceres is a planetoid rather than an asteroid which I'm not sure is generally accepted, but nonetheless planetoid is the correct term - mesoplanet is obscure and unused. Worldtraveller 14:11, 17 July 2005 (UTC)

Even by that definition you give here, it is flat out wrong to claim, as you do in Solar system, that "Just one planetoid, Ceres, lies in the inner reaches of the Solar System." Pallas is every bit as spherical as Ceres is, and Pallas is hardly the only one. I can understand if you refuse to countenance the use of the neologism "mesoplanet", but please don't go pretending that you can arbitrarily redefine words to mean what you wish they would mean.

Basically, Worldtraveller, you need to present some references to substantiate your claim that "planetoid" is used to refer only to things larger than Pallas.

--Arkuat 22:46, 2005 July 17 (UTC)

It's not my claim at all - don't try and pin what inaccuracies may exist in this article on me, I've only made minor edits to it. As I said on my talk page, and as you've quoted directly here, the article currently arbitrarily states that Ceres is a planetoid rather than an asteroid which I'm not sure is generally accepted - if you were to edit that bit substantially you wouldn't find me objecting. All I'm saying is that the word 'mesoplanet' is unscientific and should be avoided. Worldtraveller 23:01, 17 July 2005 (UTC)

Requested move

It's a proper name

• Oppose This article is clearly about the Solar System, not about other solar systems. Changed my mind, since only the semi-mythical IAU Style Manual apparently recommends using upper case. —Michael Z. 2005-07-28 16:48 Z
• Oppose: solar system is no more a proper name than solar radiation, solar energy or solar eclipse. Solar is an ajective meaning roughly "of the sun". True it's often capitalised, but IMHO it shouldn't be. --Sherool 17:27, 26 July 2005 (UTC)
• Oppose. Although it may change as we become familiar with extrasolar systems, currently usage is lower case, much as we still refer to our star and satellite as "the sun" and "the moon" most of the time (although increasing familiarity with other suns and moons changes that in certain circumstances). See Merriam-Webster, the Encyclopædia Britannica, and Encarta for examples of other reference works which use a lowercase "solar system" (which should be lowercased throughout the article as well). — Knowledge Seeker দ 05:09, July 27, 2005 (UTC)

It was requested that this article be renamed but there was no consensus for it be moved. violet/riga (t) 21:22, 29 July 2005 (UTC)

Discussion of capitalization

Read my stuff in the Solar System vs Solar system section. --Sherool 17:27, 26 July 2005 (UTC)

I did, and I disagree with you. There are many instances of solar radiation and solar eclipses, and there are also many solar systems, in the general sense (although calling them planetary systems is probably less ambiguous). But we are in one particular solar system, referred to by its proper name, the Solar System, just as Earth's natural moon is the Moon and our solar system's sun is the Sun. Choosing when to capitalize these things may be a judgement call in some contexts, but this article's title is clearly about the Solar System. —Michael Z. 2005-07-26 19:00 Z

Can you cite any official authority that makes it clear that "the Solar System" is a proper name? I'm pretty sure it's not. "the Moon" is an official name, "the Sun" and "the Solar System" is not AFAIK (hard to find good sources though). I prefeer "Sol" and "Sol system" when "formal" names are required, but those are not official either (nor widely used). I'll concede that "Solar System" is very widely used, however not consistently. For example a lot of articles and sites use "Solar System" in titles and headings, but in the text itself it's just "solar system", hard to tell if it's due to lazynes or some overall design though. --Sherool 20:42, 26 July 2005 (UTC)

I haden't read any authorities; I was just going by what made sense to me. I did a very quick search, and found a few references.[6][7] Even from a quick look, it seems that many editors don't capitalize solar system consistently. Also, the usage of the term is evolving, now that other solar systems have been confirmed (stellar systems, planetary systems). Apparently astronomers (according to the IAU Style Manual) capitalize the Sun, the Moon and the Solar System when referring to the astronomical entities, but find it okay to use lower case when referring to a light in the sky ("the sun rose"). (I found the IAU's Instructions for contributors, but haven't downloaded the files to see if they include this info.) The Chicago Manual of Style and Times Online Style Guide say to use lower case.[8]

After this admittedly very incomplete survey, I would say to go with the IAU's recommendation in astronomy articles. Are there any astronomy writers out there with a more informed opinion? —Michael Z. 2005-07-27 20:04 Z

I've been looking though the files you link to for Instructions for contributors to IAU (have not checked all though, but most seems to be duplicates in various formats (only the pdp, html, and txt formats are known to me, but looking at the "source code" of the other files it's pretty much the same as the content of the pdf's)), mostly formulas, charts, legal forms and such, however if you look in Keywords.txt in either of the two zip files linked to on the page it says "The editors of ApJ, A&A, and MNRAS have adopted these headings for use in the indexes of the three journals. (...)" (in other words it's the "house style" of those journals, so still nothing official), and goes on to list among others:

(...)
SOLAR SYSTEM
comets: general
comets: individual (..., ...)
Earth
interplanetary medium
Kuiper Belt
meteors, meteoroids
minor planets, asteroids
Moon
Oort Cloud
planets: rings
planets and satellites: formation
planets and satellites: general
planets and satellites: individual (alphabetic order)
solar system: formation
solar system: general
(...)

Not 100% sure how to interpret that (does "solar system : general", mean any solar system, or our solar system spesificaly?), but I notice that "solar system" is not capitalised, unlike other things like Moon, Earth and Oort Cloud (and Sun in a different section of the file). Not that that's conclusive proof naturaly. I agree that input from astronomy writers would be helpfull. --Sherool 21:37, 27 July 2005 (UTC)

I tend to use Merriam-Webster as my guide for spelling and such, and Chicago for my guide for other style matters. M-W clearly indicates it to be uncapitalized as I mentioned above; I cannot recall what Chicago has to say as I am out of town and my copy is at home, although you mentioned that it also prefers the lower-cased version. Given that Encarta and Britannica also favor the lowercased version, I would tend to choose that as well. I would, however, be interested in what the IAU suggests: even though astronomical contexts are different from general contexts, if they recommended capitalization I would probably favor that, although I would prefer to see some other authority, or at least professional writing, also using that. I also would appreciate any input from astronomy writers (although in my experience, members of a field tend to overcapitalize subjects dear to their hearts). Usage in this area is definitely evolving, so regardless of what we decide now we'll have to monitor the field and probably revisit this question at some point. The article itself might also make a note of the usage issues. — Knowledge Seeker দ 05:44, July 28, 2005 (UTC)

I just came across this sytle guide from NASA. In the "Astronomical Bodies" section, it says, "Do not capitalize solar system and universe." That's good enough for me unless considerable authority, like the IAU, uses capitals. — Knowledge Seeker দ 06:20, July 28, 2005 (UTC)

These discussions about capitalization are, frankly, long and tedious and bear little fruit. Meanwhile, we still haven't chosen between (nor improved on) the two redundant relative-size diagrams that are offered, and rampant confusion about the meaning of "planetoid" lurks near the end of the article. I have read the arguments for "Solar System" and the arguments for "solar system" and I can see good points on both sides. I am proposing "Solar system" as a compromise (which means this article need not be moved) between the two sides that seem to have formed up. Unlike "Sol system", "Solar system" is an established usage, and the presence of the single capital is enough to establish the phrase as a proper noun, referring to a single particular planetary system. Unless I read solid arguments on this talk page against my doing so, I will be editing this article sometime soon to change all occurrences of "Solar System" to "Solar system". Please feel free to do so if you agree with me and I haven't gotten around to it yet. And by the way, if you wish to refer to a generic "solar system" (lowercase), please use the established term planetary system instead. --Eric Forste (talk) 06:53, 28 July 2005 (UTC)

I don't know: in the absence of any authority or reference work using Solar system or Solar System, and a considerable number specifying solar system, I think the occurences should all be changed to "solar system". — Knowledge Seeker দ 07:22, July 28, 2005 (UTC)

I took the liberty of sending a mail to IAU politely asking if they had any kind of policy or standard regarding how to properly adress our solar system in formal writing. If they take the trouble to answer I'll post the reply here (if they give permission for me to do so). --Sherool 12:01, 28 July 2005 (UTC)

I've identified the IAU Style Manual, which seems to be a section of their proceedings XXB (Baltimore, 1988, ISBN 0792305825), which is out of print and not available on Amazon. One source I found (above) states that the IAU's manual recommends capitalization when solar system is used as a proper noun referring to the astronomical entity, and if that were so I would recommend using that convention in astronomy articles. However, since the style manual is out-of-print and unavailable, and all of the IAU's current materials seem to be based on general English style guides, I'm changing my mind and say that we should always write solar system in all lower case. I'll change my vote, above. —Michael Z. 2005-07-28 16:45 Z

There are three oppose votes all stating the preference for a lower-case solar system (one of them is mine), a considerable number of authority/reference works stating the same, and now User:Jeff Medkeff's comments in #Terminology points; no authority or reference works suggesting a capitalized Solar system or Solar System (although there are a couple arguments from users why they wished that capitalization were the convention). I consider that sufficient evidence and consensus and intend to modify the article to use consistent lower-case solar systems accordingly. — Knowledge Seeker দ 04:53, August 5, 2005 (UTC)

I don't think this is going to remain stable; note that the Category:Solar System is still double-capitalized. Perhaps fixing that first would be a better idea? I'd rather see consistent capitalization across the whole Wikipedia, and I think we're more likely to get that with "Solar system" than with "solar system". The issue here is not just about this one particular article. --Eric Forste (Talk) 05:22, 5 August 2005 (UTC)

I agree that consistency is to be desired. However, it seems to me that it makes sense to change the main article first—I don't think trying to change categories and satellite articles while the main article is unchanged would work that well. Has anyone found any reference work or scientific publication that uses capitalization? Or even a high-quality magazine? I just checked two of my favorites, Time\] and Scientific American, and both use lower case. Regardless if we think a new usage style would be good for the English language, or we have great reasons why other people should use Wikipedia's style of capitazliation as opposed to everyone else's, we should not be creating our own usage styles. I understand and agree with many of the reasons why capitalizing might be superior in general, but it remains that that is not consistent with current usage. — Knowledge Seeker দ 05:55, August 5, 2005 (UTC)

Okay. I'm for anything that will end this discussion and establish a definite en.wikipedia.org-wide guideline on this question. If no one comes along to argue with your edits and reintroduce capitalization, that will be great, and I'll happily decapitalize the rest of the articles that refer to the solar system. (And I'll keep on changing instances of "a solar system" or "other solar systems" to refer to planetary system instead, since this usage must, I think, bear much of the blame for making people want to capitalize "the Solar system".) --Eric Forste (Talk) 02:24, 6 August 2005 (UTC)

2003UB313 the newly discovered "tenth planet(oid)"

Just happened across this bit in the news today. It's called 2003UB313, located in the Kupiter Belt currently 97 AU from the sun, and it's equal in size or likely bigger than Pluto, or so they say:

• http://www.gps.caltech.edu/~mbrown/planetlila/index.html
• http://pr.caltech.edu/media/Press_Releases/PR12724.html

The caltech guys seems convinced it should be called a planet seeng as it's bigger than Pluto but I guess the jury is still out on that officialy. --Sherool 09:26, 30 July 2005 (UTC)

Does anybody here think that 2003UB313 is a planet or not? Personally, I think that it should be considered a planet.

Images

Isn't it redundant to have two size comparison pictures? I think one of them should go, but I'm not sure which one. I also think the mosaic is pointless, and should be replased with this image. The latter is more informative as it gives some idea of the structure of the Solar system. --The Merciful 10:56, 30 July 2005 (UTC)

I think the second one is better as the size of the Sun is seen more clearly, and it shows more objects overall.

Urhixidur 14:51, 2005 July 30 (UTC)

I myself actually slighly preferred the ohter version, mostly because in the current image Pluto and most of the moons look much like image compression artefacts. There actually seems to be a genuine compression artefact between Mars and Jupiter. The smaller objects are IMO better to show in a separate image. But you are right in that the Sun is seen more clearly, so I don't really object. --The Merciful 10:21, 31 July 2005 (UTC)

They're not artefacts ("a genuine compression artifact between Mars and Jupiter"), but, as explained in the image's page, the four largest asteroids. Urhixidur 16:19, 12 November 2005 (UTC)

I'm pretty incompetent with image processing myself, or I'd have tried to come up with a third image that's better than both of these. Frankly, I preferred the black background to the white background, although I do think that having more of the Sun show (as a part of the background) is a good idea. I only commented out the redundant image, so if anyone who is good with graphics wants to get both images and come up with an improved one and put it in there as a replacement, please go ahead. --Eric Forste (talk) 22:17, 31 July 2005 (UTC)

Archival Discussion

This talk page is getting too long (46 kilobytes) to be usable. Would anyone mind if I made a project of archiving the discussions that haven't had any new additions to them in the last six months or so? --Eric Forste 20:45, 22 July 2005 (UTC)

No, I don't mind.

Questions

1. Where is all the nitrogen? Looking at the articles of the planets of the solar system there are only traces of nitrogen (or ammonia).
2. Is anything known about the total mass of smaller objects such as asteroids, comets down to dust particles?

84.160.206.65 13:14, 11 September 2005 (UTC)

Well, perhaps the word "far" can be removed from "far higher" and "far lower" in the Uranus and Neptune section. Serendipodous 17:43, 11 September 2005 (UTC)

My question was not primarily about that "far higher" in this article. Putting the hydrogen and helium aside, there is an abundancy of oxygen in the solar system and lots of carbon is found. Why isn't there a simillar amount of nitrogen? Is our planet special in that respect, and if so, why? 84.160.212.221 19:14, 13 September 2005 (UTC)

Discovery edit

I removed the following in the course of editing the "Discovery of the solar system" section:

since it seems to deal with stuff outside the solar system. Joffan 22:37, 18 September 2005 (UTC)

Outer solar system

Outer solar system includes the Giant planets, which you can see in the article outer solar system.--Nixer 13:02, 22 September 2005 (UTC)

The article doesn't say that. It says that the outer solar system begins at the orbit of Neptune, ie, beyond the gas giant planets. Serendipodous 13:27, 22 September 2005 (UTC)

Hehe? really :-) a day ago the article said that gas giants belong to the outer solar system. So what about NASA sites, which say Cassini is an outer solar system probe?--Nixer 15:43, 22 September 2005 (UTC)

To be honest, I'm really not sure. I based what I wrote on what I initially read in the article you linked to (which was very different from what it is now). The term "outer solar system" used to mean the four gas giants plus Pluto, but now it is equally often applied to the area beyond Neptune, or even both regions at once. I honestly don't know if the term is really that well-defined. Serendipodous 21:27, 22 September 2005 (UTC)

I would say that there used to me inner planets and outer planets and now there is a region beyond the outer planets. The outer planets now consistute a middle region. The inner solar system is out to the range of the Asteroids and is dominated by the Sun, the inner planets, and their effects - most notably the Solar Wind, the middle solar system is the region dominated by the Giant Planets, their Moons, various populations of minor objects (Lagrange objects orbiting with Jupiter, Centaurs and the like) and bodies crossing into or out of the inner solar system. The outer solar system starts about the place of Neptune and goes way way beyond.--Smkolins

Just to be clear, 2003 UB313 is NOT a planet, nor is it being considered as such

Not yet. Someone here seems determined to accentuate the fact that the recently discovered world 2003UB313 either is or may be a planet. This is premature. Whatever Mike Brown (whose bias is perfectly understandable) may say on his website or in the media, right now, 2003UB313 is a Scattered Disc Object and that is what it will remain, just as Pluto, for the forseeable future, is a planet. If and when the IAU comes to a conclusion about UB313's status, then the article will be amended accordingly, but for now, any attempt to label it otherwise is misleading. Until we can say for certain what a planet is, we cannot say for certain what objects may or may not be considered planets in the future.

Also, even if UB313 were to be considered a planet, the only way it would be considered the tenth planet is if the word were defined as "an object in orbit round a star that is the size of Pluto or larger," a highly culturally biased definition that is unlikely to be chosen. If 2003UB313 is ultimately given planet status, it would more likely be as the twentieth or thirtieth planet, not the tenth.

Serendipodous 11:20, 25 September 2005 (UTC)

If NASA can say this, why can't we?--Nixer 16:18, 25 September 2005 (UTC)

Where does NASA say this, what is this that NASA says? Serendipodous 19:07, 25 September 2005 (UTC)

NASA says 2003UB313 is a planet.--Nixer 19:18, 25 September 2005 (UTC)

From NASA's Jet Propulsion Laboratory

"The planet is a typical member of the Kuiper belt, but its sheer size in relation to the nine known planets means that it can only be classified as a planet, Brown said."

The key words are "Brown said." In the days following his discovery, Mike Brown announced that he was to call it the tenth planet, but actually, the situation is complicated by the fact that, before the object can be called a planet, the IAU has to decide what a planet is. Mike Brown is of the opinion that "planet" should be considered a cultural rather than a scientific term and that Pluto should be considered the arbitrary cutoff point. This would make 313 Planet 10, but it is only one of many possibilities. A study group has been convined to settle the matter and, until they announce their decision, no one can say whether or not UB313 is to be considered a planet.Serendipodous 20:30, 25 September 2005 (UTC)

Need better pictures.

Need better pictures. Anybody argee with me?--Nixer 17:32, 26 September 2005 (UTC)

I do, but I have no idea how to import copyrighted pictures into Wikipedia. Sorry.Serendipodous 19:31, 26 September 2005 (UTC)

Coplanar Orbits

Why doesn't this article mention why the planets are all on the same orbital plane. I know that the creation of the Solar System section talks a bit about this, but it doesn't make it as clear as it could be. Here's a nice clear mention of it from here

The orbits of the planets are coplanar because during the Solar System's formation, the planets formed out of a disk of dust which surrounded the sun. Becuase that disk of dust was a disk, all in a plane, all of the planets formed in a plane as well. Rings and disks are common in astronomy. When a cloud collapses, the conservation of angular momentum causes amplifies the spin of the cloud. As the cloud spins faster and faster, it collapses into a disk, which is the maximal balance between gravitational collapse and centrifugal force created by rapid spin. The result is the coplanar planets, the thin disks of spiral galaxies, and the accretion disks around black holes.

--Quasipalm 01:35, 18 October 2005 (UTC)

Sounds good. Why don't you include it and we'll see how it looks?Serendipodous 16:45, 29 October 2005 (UTC)

What is it with this page and vandalism?

I have just had to revert about six consecutive vandal edits. I have to wonder what it is about this page that attracts so many vandals. Also, given that their content was rather offensive, it seems strange that no one noticed them for over an hour. Serendipodous 16:45, 29 October 2005 (UTC)

Star system, stellar system, solar system, planetary system ...

Hello! I've noted recent statements about why this distinction has been so characterised; however (perhaps I'm missing this), I do not see any cited references (particularly from astronomical references) substantiating these distinctions. Please corroborate and clarify. Thanks! E Pluribus Anthony 09:15, 1 November 2005 (UTC)

This article pretty much sums up the confusion. The answer, as far as I can tell, is that, as with so much of astronomy these days, the words haven't caught up with the discoveries. In times of confusion I find it is best to stick with conventional usage, rather than adopt alternatives, until the alternatives can be firmly decided upon. Hence Pluto is still a planet, because everyone says it is. Since most of the exoplanet hunters seem to use "planetary system" to describe what they find, that seems to be the word to use, even if it is misleading. Serendipodous 16:55, 1 November 2005 (UTC)

Hi; thanks for this. I don't think this is sufficient; if anything, the article promotes confusion. I'm unsure this is authoritative enough (e.g., astronomical texts/references) to justify the distinctions made in the numerous articles cited; it is bereft with uncertainties and conjecture, though I realise this may be a given considering the groundbreaking nature of such discoveries, not to mention the dichotomy between popular usage (e.g., in science fiction, which almost universally refers to star systems other than our own as being solar) and correct astronomical usage. Why? Early in the MSN article:

To say "planetary system" does not make clear whether a star is involved, and to some those words might suggest something else entirely: a planet and its moons.

However in each of the Wp articles, the distinctions are clearer than this without citing references thereof; I think this is misleading and challenge them. It may be a case of simple (or perhaps not-so-simple) grammar. Rationale:

• solar is an adjective and refers to (and is derived from) Earth's sun; by extension, the solar system refers to everything in the Sun's association.

e.g., The Sun, nine major planets, their natural and artificial satellites, asteroids, planetoids, comets, Kuiper belt, and everything in the Sun's association form the solar system (or Solar System).

• by analogy, stellar (an adjective), even extrasolar, and star (adjective and noun) are applicable to other stars just as solar is to our sun.

• similarly, planetary system methinks refers to a system of planets or associated bodies, not the entire stellar system in toto; as above the solar system is much more than its planets.

• e.g., The largest Jovian planetary system in our solar system comprises Jupiter, its many moons (including the four Galilean moons), rings, and associated bodies.

• Thus, a solar system or stellar system can contain no, one, or many planetary systems.

• e.g., The largest of the nine planetary systems in the solar system is Jupiter's.
• e.g., As of this date, planetary systems are believed to exist in the Upsilon Andromedae and Gliese 876 star systems, among others, Moreover, extrasolar planets (and, hence, the development of life) around multiple (e.g., binary) star systems may be made difficult due to variations in gravitation.

These aren't at all clarified in the article cited and definitions provided. I'm gonna investigate the various definitions from various sources, and I'll apprise you of my progress and make appropriate changes; until then, I think all of these definitions are somewhat circumspect. Thoughts? Thanks! E Pluribus Anthony 19:20, 1 November 2005 (UTC)

A quick search of GoogleScholar reveals that scholarly papers almost exclusively use "planetary system" for extrasolar systems and "stellar system" for multi-star systems. Hope that helps.Serendipodous 19:44, 1 November 2005 (UTC)

Hey; thanks. I don't think it does; I think it demonstrates that planetary systems comprise the star systems, or even stellar systems, being investigated (e.g., what of binary star system, which is fairly common?). I will investigate; thank you for your indulgence. :) E Pluribus Anthony 19:56, 1 November 2005 (UTC)

Further to your Google reference: if you actually probe further, you will see (as I suggest above) that planetary systems are variably referred to within the context of star systems/stellar systems for a number of the references. Pending additional investigations, the Wp definitions shall be modified. Thanks! E Pluribus Anthony 22:13, 1 November 2005 (UTC)

---

Definitions

Hello again! Further to discussions and after some digging, my search for authoritative definitions for some of these terms has born some fruit:

• solar system - this is pretty clear-cut:

• Solar System – A group of celestial bodies comprising the Sun and the large number of bodies that are bound gravitationally to the Sun and revolve in approximately elliptical orbits around it....

— Collins Dictionary of Astronomy (ISBN 0-00-710297-6), p. 382

• Solar System – The collective name for the Sun and all the bodies that orbit it. It includes the nine major planets and over 100 known satellites, plus countless asteroids, comets, and meteoroids....

— Oxford Dictionary of Astronomy (ISBN 0-19-860513-7), p. 420

• stellar system – "A gravitational system of stars."

— The McGraw Hill Dictionary of Astronomy (ISBN 0071410473), p. 125

This definition implies it can be correctly used for systems with more than one star, e.g., binary systems, with their constituents. Whether it can be used for one star alone and associated bodies is not wholly clear, in which case star system is likely more appropriate; however, a logical assumption can also be made that stellar, being an adjectival form of star (or stars, as per Oxford English Dictionary), can be used in a similar way to solar when referring to the Sun (Sol).

• star system – Strangely, I could not (yet) find printed references/definitions for this term; see solar system and stellar system

• planetary system – ... A system of celestial bodies in orbit around a star including planets, moons, asteroids, comets, and dust.

— The Universal Book of Astronomy, from the Andromeda Galaxy to the Zone of Avoidance (ISBN 0471265691), p. 394

... A system of planets and other bodies, such as comets and meteroids, that orbits a star. The Sun and its planetary system together comprise the solar system.

— Collins, p. 314

Note the distinction between solar and planetary system, viz. the Sun (or central star). This clearly does not include the central star(s) as part of the system, so references to the stars and their planets (in an extrasolar context, in toto) can more correctly be dubbed as star system or stellar system, and even improperly, as 'solar system' (e.g., as commonly referred to, like in Serenity).

In some respects, some of these clearly differ with definitions and interpretations already presented in the appropriate Wp articles. Based on this information and unless there are opinions/citations to the contrary, I will be making these appropriate editions to the relevant articles. Thanks! E Pluribus Anthony 01:21, 6 November 2005 (UTC)

"star system" is a term associated more with science fiction than astronomy.Serendipodous 10:27, 6 November 2005 (UTC)

Given the redirect and the current definitions, it begged an inquiry.

As well, this is a generalisation that should be cited, if at all. An online search actually reveals more instances of star system, with its various meanings (and a similar number of instances of planetary system), than stellar system. You will note the former term is used frequently in astronomical works, too ... particularly when referring to multiple star systems (e.g., binary system). Unless sources can be cited alternatively, this will guide my edits. E Pluribus Anthony 11:16, 6 November 2005 (UTC)

Your most recent edit is unclear.

When talking about a specific stellar system, including the star(s) and bodies associated with them through gravity, it is usual to shorten it to "the <name> system" (e.g. "the Alpha Centauri system" or "the 51 Pegasi system"). The celestial bodies orbiting the Sun, and other stars, are referred to as planetary systems.

Granted; this has since been changed to:

When talking about a specific stellar system, including the star(s) and bodies associated with them through gravity, it is usual to shorten it to "the <name> system" (e.g. "the Alpha Centauri system" or "the 51 Pegasi system"). The planets and amalgam of bodies orbiting the Sun, and similar systems of non-stellar bodies orbiting other stars, are referred to as planetary systems. E Pluribus Anthony 13:24, 7 November 2005 (UTC)

"Celestial bodies" can be planets or stars. "Planetary system" is never applied to multiple star systems, and is only applied to stars and their orbiting planets. The ambiguity is whether "stellar system" can be applied to planets as well as stars, not whether "planetary system" could be applied to stars as well as planets.

On that topic, I don't see where the definition of "stellar system" is unclear. It says that a stellar system is a system of gravitationally bound stars. Plural. It therefore cannot be applied to single stars, and since single star systems are planetary systems, it cannot be applied to planetary systems.

Serendipodous 12:57, 6 November 2005 (UTC)

This is, after all, a collaborative effort. However, your edition doesn't make sense: you've removed notation that the planets and flotsam of other bodies in our own solar system (i.e., not including the Sun) comprise a planetary system; note that a planetary system, as per definitions above, include a multitude of other bodies and do not include the central star(s). Are you implying that a planetary system(s) cannot exist within a single or multiple star system?

The definition of stellar system was (and is) unclear given the definitions of other terms indicating differently, soon to be resolved.

Furthermore as far as stellar system is concerned, coupled with the above definitions, there is no ambiguity: I again refer to the Oxford English Dictionary which refers to the adjective stellar as being "of or relating to a star or stars"; hence, singular or plural. Stellar is to star(s) as solar is to Sol. E Pluribus Anthony 13:20, 6 November 2005 (UTC)

I've made additional editions to rectify recent equally "inelegant" (and somewhat inaccurate) edits: namely, clearer systemic distinctions and cited definitions above for Solar System which capitalise both terms; I am including both (with a parenthetical for SS). I understand a discussion has occurred regarding nomenclature and for moving the article to SS; I am not advocating this but am only listing clearly cited references either way. Please indicate why you are citing only one preferred term. Until this can be substantiated, cited references will guide my editions. E Pluribus Anthony 14:39, 7 November 2005 (UTC)

RE: etymology and mythology of Earth

Editions are being made regarding the root for Earth in a section of the "Solar system" article that are not wholly precise; the following can be found in Merriam Webster's Collegiate Dictionary (11th ed.) regarding the etymology of the word "Earth" (with wikilinks):

... [ ME erthe, fr[om] OE oerthe; akin to OHG erda earth, Gk era] (before 12c.) ]

and for Terra:

... [ NL, fr. L. land ]

Moreover, the mythical Greek goddess Gaia (mythology) (also the Greek word currently in use and previously for "Earth") was the precursor to the mythical Roman goddess Terra (the latter of which is known in Romance languages).

I'm willing to admit error/refinement and or the need for balance, but Serendipodous' interpretations and cited (in summary) "studies" are insufficient for describing this without citations. To that end, please cite sources supporting this contention or contrary to the above noted citation. Until then, mythical notes regarding Gaia or its Greek root should be noted appropriately or only as a general summary/assessment statement. Thoughts? Thanks! E Pluribus Anthony 15:17, 5 November 2005 (UTC)

First, before you accuse me of not citing my sources, make a direct connection between the Greek "era" and the Goddess Gaia, because I don't see one there.

Second, it is incorrect to say that the Greek Gaia was the "precursor" the Roman Terra; mythology isn't that linear. Who knows how long the Romans were worshipping their Goddess before they wrote their myths down? Just because the Greeks wrote theirs first doesn't mean they gave their gods to the Romans.

Finally, the source you cited only claimed that the word was "akin" to the Greek "era", not that it was based on it. Both Greek and English are Indo-European languages; of course they would have cognates. The Greek word for "mother" is "mater," while the Farsi for "brother" is "biradar" but no one claims that "mother" is based on Greek, or "brother" on Farsi.

To be sure, I contacted Dave Wilton, a lexicographer who runs a website dealing with these things. This is what he said:

" The English word is definitely from the common Germanic root and not a borrowing from Latin or Greek--note the emphasis on English.

There may, however, be a connection between the Germanic root and the Greek word era. The Greek and the Germanic are apparently cognates, but which one is the origin or if there is an older, shared Indo-European root is unknown. No other cognates, outside of Germanic or Greek, are known."

Ergo, while there MAY be a link between the words "era" and "earth" it is impossible to know if it is a "father/son" relationship, as you are supposing, or a "distant cousin" relationship, which to me seems more likely. Regardless, that still doesn't justify linking "era" to Gaia.

Serendipodous 15:33, 5 November 2005 (UTC)

First, I'm requesting a citation of the original contention, which is still not supported. (This is also a similar issue with the "solar system" et al. definitions.) Second, I've included a dictionary reference to the root for Earth (and I, nor others, may know who Mr. Wilton is, despite his summary), so it can be argued the term is not derived from any goddess, but from era or from prior words for land. The article previously gave the impression that Earth was derived unequivocally from Roman myth, which is imprecise. If any of this can't be confirmed or resolved, unequivocal mention in the article should be nixed.

In addition, head on over to the Earth article for use of the term geo and, similarly, Gaia et al.

Moreover, it is well known that many Roman gods were derived from Greek ones: Ares > Mars; Zeus > Jupiter, etc. Almost all Roman gods have a Greek precursor/analogue. Of course, the Romans morphed them for their own purposes and conceived of few (e.g., Edith Hamilton's Mythology). Further to that, I'm supporting including the Greek Gaia as the precursor goddess to the Roman/Latin Terra (actually Tellūs), since both are appropriate, not necessarily that Gaia is the root word (and apologise for this prior presentation). Thoughts? Thanks! E Pluribus Anthony 15:55, 5 November 2005 (UTC)

I'm not entirely clear on what contention you want me to cite. Your definition alone shows that Earth is a Germanic word derived from Anglo-Saxon. Here is as good a citation as any showing that the word is of Common Germanic origin, which means it is as old, or older, than Greek.

This is the version I dispute. Again, nothing you've said or cited here (but one edition you made) clarifies this and it is imprecise. E Pluribus Anthony 16:28, 5 November 2005 (UTC)

Please stop using the word "derived." There is no evidence in the citation that YOU GAVE that "Earth" is derived from "era." All it says is that the two words are "akin". Since all Indo-European languages are ultimately related, such cognates are inevtiable, but you can't say that one word is "derived" from another simply because the other was written down first. People were speaking Germanic lanaguages for just as long as they were speaking Greek languages; the only difference is that the Germanic people didn't write their language down, and the Greeks did. Ergo, we have evidence of earlier Greek languages than we do for Germanic langauages.

I will use terms as desired and if appropriate: its a dual argument of etymology and mythology. Earth is the anglicised version of the goddess Gaia (which is also Earth in Greek), "geo-" is derived Gaia, and anything else relating to the Earth. What about this do you challenge? E Pluribus Anthony 16:28, 5 November 2005 (UTC)

And I still don't see how you justify bringing "Gaia" into the article, when neither "Earth" nor "era" have anything to do with her. The point of the original post (which, frankly, I thought was a bit pointless) was to remind people that in some lanaguages, Earth was still called "Terra," after the Roman goddess of Earth. The only language that still calls Earth Gaia is Greek. I ask again, what does that have to do with English? Serendipodous 16:11, 5 November 2005 (UTC)

For reasons above: the topic of note deals with myth and my examples are completely valid. If you cannot adequately justify Terra in the article and cite this appropriately (and Earth as being derived from Roman myth alone), and I don't think you have, general mention alone should be made. E Pluribus Anthony 16:23, 5 November 2005 (UTC)

You are making absolutely no sense. When did I say that "Earth" was derived from Roman myth? As I have said three times in this peculiar argument already, "Earth" is an Anglo-Saxon word derived from ancient Germanic. It is neither Roman, nor Greek. It is not the name of a goddess- it merely means "ground." "Terra" the word for Earth in Portuguese, Italian, Spanish etc. is defintely derived from Roman myth, and yes, every Roman god has a Greek counterpart. But if we're going to mention the Greek counterpart for Earth, we may as well remind the world that Jupiter was also called Zeus, that Mercury was also called Hermes and that Venus was also called Aphrodite. But what would be the point?Serendipodous 16:30, 5 November 2005 (UTC)

Sheesh. The prior version of the article is imprecise and I dispute it; after your 2nd ed. (below) to my edits, they did not accurately reflect both the etymology and mythology of the term; re-read the root for "geo-".

Since all the planet names/gods have counterparts, and it would be futile to list them all, your first edit of this should suffice; let the links to the appropriate article elaborate. E Pluribus Anthony 16:38, 5 November 2005 (UTC)

But Earth ISN'T named after a Greek or Roman god! It's Germanic! It is named after a Roman god in Romance languages, but English is not a Romance language! It is Germanic. How much clearer can I be? Serendipodous 16:46, 5 November 2005 (UTC)

My point exactly! You've clearly stated it here, but it wasn't clear in the article. This should be stated explicitly in the article in addition to references of myth. I don't think this was the case beforehand (re-read the prior version and you'll see what I mean). I still believe that Gaia, as the mythical precursor/analogue to the goddess Terra, should be included given the emphasis on myth, but its mention in the Earth article is sufficient for now. Anyhow, thanks for your engagements. E Pluribus Anthony 17:09, 5 November 2005 (UTC)

Look at this:[9]--Nixer 18:07, 5 November 2005 (UTC)

Hello, Nixer; thanks: I understand. The debate was one of etymology and mythology, and the previous versions didn't crystallise this dichotomy correctly. The current edition reads better and is fine, though it isn't perfect. Merci! E Pluribus Anthony 19:03, 5 November 2005 (UTC)

Hello. To be clearer, and since languages are being mentioned alongside myth, I am proposing the following edition(s) regarding the names of planets and Earth in particular:

...All planets are named after or derived from gods and goddesses from Greco-Roman mythology; however, Earth (a Germanic word), is known in many Romance languages as Terra, the Roman goddess of the Earth.

OR

...Eight of the nine planets are named after or derived from gods and goddesses from Greco-Roman mythology; Earth, a Germanic word, is known in many Romance languages as Terra, the Roman goddess of the Earth.

or variation. Thoughts? If there are no objections ... Thanks! E Pluribus Anthony 03:07, 6 November 2005 (UTC)

...Thus, the second option above has been included for greater clarity. Enjoy! E Pluribus Anthony 11:39, 6 November 2005 (UTC)

I wouldn't cry over either version, though mentioning that "Earth" is a Germanic word seems rather redundant. English is a Germanic language; Germanic languges, last I checked, contained Germanic words. Serendipodous 11:57, 6 November 2005 (UTC)

Thanks for the approval. Given the mention of Romance languages in that same sentence, its inclusion and distinction is necessary to provide balance for what was an imbalanced statement. E Pluribus Anthony 12:01, 6 November 2005 (UTC)

hello -- you could save a lot of confusion by keeping mythology and etymology clearly separate. Earth as a Mother Goddess is attested in countless cultures, and you cannot really say who derived it from whom. It's just an archetype. In etymology, you have to pay due attention to the fact that English "Earth" has a double meaning, Earth the planet (i.e., since it wasn't thought of as a planet before Modernity, the solid ground we walk on in its entirety), and earth, the substance (soil). As you say, the word is from Gmc. *ertho, originally meaning "Foundation". In the case of Terra (mythology), note that Tellus and Terra are not the same word. Terra originally referred to the substance, "dry earth" (cf extorris). "Gaia" has no known etymology and referred to a Mother Goddess from its earliest attestation. Plthvih meant "the Flat", "the wide expanse". The PIE "proper name" of Earth was "Dghon", but this was possibly itself an old term for "dry earth", cognate to a root degh for "burn" that is also preserved in day. If you lump all these notions together and argue about them as a whole, it is not surprising that there should be inaccuracies and misunderstandings. dab (ᛏ) 16:18, 12 November 2005 (UTC)

Dab, I am second time asking you to look at this: http://www.bartleby.com/61/roots/IE130.html] This is not only Germanic, but PIE root, meaning earth (not Foundation). PIE had several words for Earth, such as dghem, ghem (not dghon), teres, lendh and others.--Nixer 21:17, 12 November 2005 (UTC)

Thanks for this ... this has been my position all along! Though only somewhat passable, the current entry (as did the original one) still marries the two notions and does not clearly distinguish between the etymology and mythology of the term. To that end, I'd appreciate your/other attempts to edit and balance the relevant statements in the article. Thanks again!  :) E Pluribus Anthony 16:29, 12 November 2005 (UTC)

Quote

Although the term "solar system" is frequently applied to other star systems and the planetary systems which may comprise them, it should strictly refer to our system specifically: the word "solar" is derived from the Sun's Latin name, Sol (and the term sometimes appears as Solar System). When talking about another stellar system (or planetary system), including the star(s) and bodies associated with them through gravity, it is usual to shorten it to "the <name> system" (e.g. "the Alpha Centauri system" or "the 51 Pegasi system").

There is a fifty-fifty possiblity that other (clears through, then says sarcasticlly) stellar systems, could have a sun, too. --Wack'd About Wiki 13:11, 19 January 2006 (UTC)

Orbital resonance

From revealed orbital resonance with 27 in closest integer denominator for all planets, could you now rewise the note about Neptune not being at its place, and that Pluto's orbit shows it does not behave like every other planet does ?

The planet between Jupiter and Mars already had a name, used in some occult circles, but I do not remember that name just now... (will add this soon)...

I would add the orbital resonance value to the table near the end of this article, but it would not fit the scaling to earth=1 in other columns ...

Any idea?

Semi Psi 17:36, 1 February 2006 (UTC)

I'm not familiar with what you speak of. Is this a new "law" of orbital resonances? What the article says is that Neptune is far closer than predicted by Bode's Law; if there is another law, it would need to be discussed separately Serendipodous 17:52, 3 February 2006 (UTC)

Pluto and Neptune

I know that on a flat schematic diagram, the two paths of the these planets cross, but i also know that pluto is inclind at 17.5 degrees difference to the rest of the solar system, does anybody know if the two planets paths cross in 3D, or does pluto pass under or over neptune? and also if there paths do cross, will they ever collide? thanks Philc 0780 18:46, 10 March 2006 (UTC)

I don't fully grasp the mechanics of it, but apparently Pluto and Neptune's 3:2 orbital resonance (Neptune goes round the Sun 3 times for every two orbits of Pluto) means Pluto and Neptune cannot collide. Serendipodous 20:57, 10 March 2006 (UTC)

In 3D space, the orbit of pluto near perihelion (where it crosses neptune's orbit) is far out of the plane of the rest of the planets. Also, because of the 3:2 resonance between neptune and pluto, whenever pluto is at perihelion, neptune is roughly 90 degrees ahead of or behind pluto. Here is an image that shows all the places that pluto can be, relative to neptune. You'll see that they don't ever get within even 15-20 AU of each other, which is about 2-3 billion kilometers. Short answer: No, they will never collide. shaggy 21:08, 10 March 2006 (UTC)

Trimming

This article is very long, and I've just conducted some rather merciless trimming and merging of paragraphs that, I felt, while informative, did not directly relate to the topic heading, which is to explain what the Solar system is and, to a lesser extent, how we arrived at that conclusion. I've indicated redirects to related topics that offer more information on tangental subjects. Serendipodous 13:45, 1 April 2006 (UTC)

Xena

Now that NASA has confirmed [10] the existence of the 10th planet, Xena, should this article reflect this new information? --Kmsiever 00:00, 12 April 2006 (UTC)

It has yet to be determined whether or not Xena should be defined as a planet or not. Anarchist42 00:41, 12 April 2006 (UTC)

Confirmed is not the right word. NASA has offered an opinion as regards the identity of "Xena", but it is not actually possible to confirm an object's identity as a planet if, as is currenty the case, no single definition for planet exists. It is not NASA's job to define a planet, that job belongs to the IAU and they've said (touch wood) that they'll release a definition by early September. Then we will be able to confirm whether or not "Xena" is a planet. Serendipodous 12:46, 12 April 2006 (UTC)

Confirmed is the right word. They confirmed that Xena does exist. I didn't say they confirmed that Xena is a planet nor that they have defind what a planet is. --Kmsiever 14:32, 12 April 2006 (UTC)

Xena's existence has been confirmed for some time now; since January, 2005 in fact. It already has a subsection all to itself. I am confused as to what you feel this article needs to say about it. Serendipodous 16:01, 12 April 2006 (UTC)

AU

Astronomy is more of a hobby interest than a passion as it is with some people, but I would feel it appropriate to add the AU from the Sun as follows: "67.9 ± 29.7 AU" into this area. For some reason I thought it would be beneficial to have this information included into this section since other AU distances are included for other objects as well. Would someone care to comment on the accuracy of the distance I calculated and also the insertion of this (if/when we determine it's correct) into the main section. --unixgold 11:23, 12 April 2006 (UTC)

Pluto's orbital distance is also given as an average in that table, even though it too has a very elongated orbit. It's just the mean orbital distance, and really has little bearing on the actual orbital circumfrence of the world in question. The section on UB313 lists its greatest and least orbital distances. Serendipodous 12:46, 12 April 2006 (UTC)

Change to "Sol system" or "Sol solar system"

As more and more planets are being discovered in other solar systems I think it's time to look forward and make some changes to this article. The article "Solar System" should talk about systems in general, planet formation etc. and have a list of systems discovered so far. The current article should be moved to "Sol System" and remain largely unchanged. Opinions?

I would completely disagree - solar system is specific to our Sun, planetary system is a more generic term. 'Sol system' is generally only seen in sci-fi, and never in the astronomical literature. Worldtraveller 15:24, 22 April 2006 (UTC)

Ditto. See also archived earlier talk Talk:Solar system/Archive 001. Femto 15:42, 22 April 2006 (UTC)

Seems "Sol system" is used more and more but for now let's leave it. I guess we'll have this discussion again in about 50 years :)

About removing the category

Just to explain, when I loaded the article on another machine, the category bar, for some unknown reason, was blocking out the recently added table of solar system links. I figured since the article already had a complete list of links to every solar system topic, it really didn't need a link to the category list and, on balance, decided to get rid of it. However, now that it's been reinstated it seems to be back where it's supposed to be, so all's well. Serendipodous 18:46, 11 May 2006 (UTC)

Any ideas on how to improve this page?

I think this page could do with a clean up, but for the life of me I can't figure out how to go about it. These days pretty much the only changes made to this page are by vandals, and I think it would be nice if we could get this page up to feature quality. Any thoughts?

Note: I've been experimenting with shifting the page's layout, and I've thought that the table of planetary orbits really belongs in the "structure and layout" section, and the "major planets" table has been moved further up. I actaully think it belongs further up still. I'm also not too fond of the orbit/diameter graph, as it's dull and nearly impossible to read. I've been thinking of getting rid of it, but I won't do it without consensus.

EDIT: I experimented with removing that graph and I think it improved the page considerably. I've taken it down. If anyone feels that the graph should still be included, I'll post it here and they can revert it back if they wish.

Plot of equatorial diameter versus semi-major axis for the Sun, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Vertical pixels are in units of equatorial diameters of Pluto, and horizontal pixels are in units of (4 * semi-major axis of Mercury).

Serendipodous 12:25, 15 May 2006 (UTC)

I'd be interested in a push on solar system to get it up to featured quality - I think it's one of those at the moment where there's lots of content but a lack of organisation and polish. Difficult one to get right as it's such a broad topic. What I would suggest would be to start by setting out here the structure you'd give it if you were starting from scratch, then once that's sorted fit all the existing content into it, then fill in any gaps that identifies. I just did this with Mercury and was very happy with how it turned out. Worldtraveller 13:23, 15 May 2006 (UTC)

• I think we should add some details of the 10th planet

--Ninad 19:35, 20 May 2006 (UTC)

There is a section on that already, under "2003 UB313". Serendipodous 10:34, 21 May 2006 (UTC)

Heliopause

I don't believe that the sun's light just stops. I believe that the radiation and heat has a limit, but I don't believe in light having a limit.--Gangsta-Easter-Bunny 12:50, 28 May 2006 (UTC)

The solar wind isn't made of light; it's made of plasma. Second, it doesn't just stop; it bumps into the interstellar wind coming the other way and gradually loses strength until it can no longer hold the opposing wind back. And thirdly, heat is light, so it is just as limitless as any other form of light. Some forms of radiation, such as x-rays and gamma rays, are light as well. Serendipodous 13:15, 28 May 2006 (UTC)

Good point. I didn't think of that. But I still say they cansee the Sun in places like Alpha Centauri, like we can see them.--Gangsta-Easter-Bunny 03:30, 29 May 2006 (UTC)

You're right. But the solar wind isn't light. It's made of particles that are ejected from the Sun. So while someone at Alpha Centauri could certainly see the light from the Sun, the particles that make up the solar wind won't reach there. —Bkell (talk) 03:33, 29 May 2006 (UTC)

Origin and age

What is the rationale that there are gases in the inner planets? If the heaviest materials stayed close to the sun, and the lightest materials were thrown more distant, then the worlds near the sun would get less of an atmosphere. Then again, maybe the near planets would conglomerate fairly quickly, and then pick up some atmosphere just after the gases left the sun. But then why would the Jovian planets be so big? And if the solid contents of those planets (not including their atmosphere) is not that large, how would it collect gases? Does anyone have a good explanation for this? (I thought this was the most relevant place to pose this question.) D. F. Schmidt 02:37, 31 May 2006 (UTC)

The atmospheric gases were trapped in gas form in the liquid matles of the planets during formation and subsequently erupted out of the crusts via volcanism. Serendipodous 08:18, 31 May 2006 (UTC)

Why would the lighter gases be among the heavier elements such as rock? D. F. Schmidt 14:16, 31 May 2006 (UTC)

Dust grains made of materials with high melting points condense first in an interstellar cloud; subsequently these dust grains will act as condensation seeds for more volatile elements. It's not entirely clear how much of the volatiles comes from outgassing and how much has been added later by comets (see also Origin of water on Earth). Icek 17:05, 1 June 2006 (UTC)

White dwarf - gravitational pull

I notice that the article currently contains When the sun becomes a white dwarf, its gravitional pull will be almost non existent, sending the planets ever outward

I think this is a bit misleading. White dwarves remain very massive objects - and I've certainly seen predictions to suggest that the Sun's eventual white dwarf state will have at least 0.5 solar masses. If that is the case, then the Sun's eventual gravitational pull will be at least half it's present value, and not "almost non existent". Anyone else have any comments? Richard B 22:47, 24 June 2006 (UTC)

There seems to be a lot of contradictory information on this, but according to at least one source, you're right. Since the source is relatively detailed, I'm sticking to its interpretation. Serendipodous 23:15, 24 June 2006 (UTC)

External Link re-added

I've readded the external link http://devhed.com/solar-system, after discussing it with Zanaq, who removed it. He's still not thrilled with the link, but sees that it does have subjective value.