Talk:Solar System/Archive 1

message: 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)
thread_title: Surface

message: 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)
replies: text: When I did the asteroid groups I got all the information from , 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)
replies: text: 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)
replies: text: 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)
replies: text: 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)
replies: text: Done, how's it look? Bryan 07:51, 21 Mar 2004 (UTC)
replies: text: This is really neat --- asteroid is a lot crisper and easier to read. --hike395 17:35, 21 Mar 2004 (UTC)
thread_title:  Overlap with Asteroid Entry 

message: 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)
replies: text: 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)

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

message: 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)
thread_title: The Edge of the Solar System

message: (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)
replies: text: 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)
thread_title:  Misuse of the word "planetoid" to mean something other than "minor planet" 

message: 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)
thread_title:  2003UB313 the newly discovered "tenth planet(oid)" 

message: 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)
thread_title: Archival Discussion

message: # Where is all the nitrogen? Looking at the articles of the planets of the solar system there are only traces of nitrogen (or ammonia).
# 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)
replies: text: 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)
thread_title: Questions

message: 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)
thread_title: Discovery edit

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

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

message: 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)
thread_title:  Coplanar Orbits 

message: 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)
thread_title: What is it with this page and vandalism?

message: 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)
thread_title:  Quote 

message: 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)
thread_title:  Orbital resonance 

message: 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)
thread_title:  Pluto and Neptune 

message: 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)
thread_title: Trimming

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

text: 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)
replies: text: 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)
replies: text: 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)
thread_title: Xena

message: 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)
replies: text: 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)
thread_title: AU

message: 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)
thread_title: About removing the category

message: 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.
Serendipodous 12:25, 15 May 2006 (UTC)
replies: text: 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)
replies: text: There is a section on that already, under "2003 UB313". Serendipodous 10:34, 21 May 2006 (UTC)
thread_title: Any ideas on how to improve this page?

message: 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)
replies: text: 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)
replies: text: 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)
replies: text: 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)
thread_title:  Heliopause 

message: 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)
thread_title:  Origin and age 

message: 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)
replies: text: 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)
thread_title: White dwarf - gravitational pull