Talk:Solar System

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 :).

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.

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)

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)

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 MediaWiki:Footer_SolarSystem. I'm happy to continue the discussion over at MediaWiki talk:Footer_SolarSystem. -- hike395