Talk:Solar System

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)

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)

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:Footer_SolarSystem. I'm happy to continue the discussion over at MediaWiki talk:Footer_SolarSystem. -- 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.

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)

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

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

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)

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 artifacts. There actually seems to be a geniune compression artifact 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)

I'm pretty incompetent with image processing myself, or I'd have to 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)