Talk:Solar System

Heliopause

Please don't take this wrong, Serendipodous, for I consider your clarification to be an excellent edit. I'm curious about what you wrote in the edit summary: ". . . the solar wind has no upwind or downwind." In that particular context, where the "upwind" and "downwind" refers to the flow of the interstellar medium, the motion of the Solar wind is, of course, always into that medium. In other contexts, such as the effect of the Solar wind upon the magnetic field of the Earth, there is a significant "upwind" and "downwind" to the Solar wind, isn't there? (Ref.: Earth's magnetic field)

Also, a later statement is made that "Beyond the heliopause, at around 230 AU, lies the bow shock, a plasma 'wake' left by the Sun as it travels through the Milky Way." This raises questions in my mind: How can science assume that there is a "flow" to the interstellar medium, when next to nothing is known about that medium? Might that medium be immobile, and only appear to flow against the movement of the Sun and Solar system around the center of the galaxy? Isn't it incorrect to refer to the "flow" of the interstellar medium in this article as if it definitely exists? The only thing actually "flowing" could just be the Solar system through the galaxy, correct? (If I'm right about this, then there is no "upwind" or "downwind" to the interstellar medium!) It seems we are using terms (such as "flow of plasma", "upwind" and "downwind") in this article as if they truthfully apply, when, in truth, we don't know if they apply, don't you agree?
 —  ^{.`</sup>^) Paine Ellsworth<sup>diss`cuss} (^^`.  05:51, 4 September 2009 (UTC)

I suppose there is an upwind or downwind to the solar wind; towards or away from the Sun. But since both edges of the heliopause are away from the Sun, the solar wind's upwind and downwind wouldn't apply. As to the interstellar medium being immobile, that's impossible. Nothing in space is immobile, because nothing can be. Space has no gravity and no friction, so there's nothing to slow anything down. Serendi^podous 06:06, 4 September 2009 (UTC)

You can read here or here. Ruslik_Zero 08:01, 4 September 2009 (UTC)

That's all quite interesting, but it's still conjecture and OR. There's nothing in the literature that I know of that would support your idea that it's "impossible" for the interstellar medium to be immobile. Moreover, if the interstellar medium is flowing, who's to say it's not flowing in the same direction as the Solar system? or in a "crosswind" direction? Bottom line is nobody really knows for certain, so the "flow", "upwind" and "downwind" wording must be OR, and it ought to be removed from this encyclopedia.

 —  ^{.`</sup>^) Paine Ellsworth<sup>diss`cuss} (^^`.  08:27, 4 September 2009 (UTC)

Ruslik just provided you with two scientific sources that describe the heliopause's interaction with the motions of the interstellar wind. Serendi^podous 09:28, 4 September 2009 (UTC)

"This current of tenuous partially ionized low density ISM has a velocity relative to the Sun of ∼26 km s−1." This is written on the page one of one of two refs that I provided. Ruslik_Zero 10:08, 4 September 2009 (UTC)

Another paper: "At present there is no doubt that the local interstellar medium (LISM) is mainly partially ionized hydrogen gas moving with a supersonic flow relative to the solar system." Ruslik_Zero 10:13, 4 September 2009 (UTC)

And doncha jus' luv it! when a "scientist" says "At present there is no doubt . . .". Makes me wanna jump on the next rocket goin' that way just to see if it's really correct. So for now, I shall bow to the present interpretation of data and "back off". And may we all live long enough to see if ol' Vlad is correct.

 —  ^{.`</sup>^) Paine Ellsworth<sup>diss`cuss} (^^`.  10:00, 5 September 2009 (UTC)

We do have spacecraft in that region now. Rocket-launched and everything. The Voyagers have been inside the heliosheath for years and both have noticed it billow and buckle under pressure from the interstellar wind. Serendi^podous 15:50, 5 September 2009 (UTC)

New Article http://www.universetoday.com/2009/11/20/cassiniibex-data-changes-view-of-heliosphere-shape/ --Craigboy (talk) 04:42, 19 December 2009 (UTC)

Bugger. Assuming this is correct I'm going to have to rewrite about 20 different articles. Serendi^podous 15:15, 19 December 2009 (UTC)

--Suggested change for "Farthest Regions"-- For the 3rd sentence in the "Farthest regions" section, I recommend we change the word influence to dominance. "However, the Sun's Roche sphere, the effective range of its gravitational dominance, is believed to extend up to a thousand times farther." While we believe gravitational influence to be practically infinite, using the word "dominance" instead illustrates a better understanding of the concept of the "Roche sphere" or Hill sphere. —Preceding unsigned comment added by Xjxj324 (talk • contribs) 23:57, 26 January 2010 (UTC)

Good idea Serendi^podous 00:05, 27 January 2010 (UTC)

Possible Link

{{editsemiprotected}} Request: Please add http://www.quitethehike.co.uk to the 'external links section'. The webpage http://www.quitethehike.co.uk is an interactive look at the size of the galaxy, drawing attention the the distances between the planets themselves. It has some interesting trivia about the planetary objects themselves (which mostly comes from Wikipedia, it seems).

•  Not done This addition of this link would likely be contested; please obtain consensus here through discussion for its addition. If you are having trouble getting input, ask for a third opinion. CIreland (talk) 11:05, 23 January 2010 (UTC)

Ceres, beyond Neptune ?!?

"Beyond Neptune's orbit lie trans-Neptunian objects composed mostly of ices such as water, ammonia and methane. Within these regions, five individual objects, Ceres, Pluto, Haumea, Makemake and Eris, are recognized to be large enough to have been rounded by their own gravity, and are thus termed dwarf planets. "

Ceres is recognized as a dwarf planet. But, Ceres is not beyond Neptune's orbit at all. This wording is misleading. It should be corrected. Cazaux (talk) 22:53, 29 January 2010 (UTC)

I thought your comment was good until I noticed the lead in. The paragraph starts with: "The Solar System is also home to two regions populated by smaller objects. The asteroid belt, which lies between Mars and Jupiter, is similar to the terrestrial planets as it is composed mainly of rock and metal." -- Kheider (talk) 23:50, 29 January 2010 (UTC)

What's inclination between ecliptic and the galactic plane?

--MathFacts (talk) 10:03, 11 February 2010 (UTC)

86.5 degrees. I'll add it.Serendi^podous 12:02, 11 February 2010 (UTC)

Planet introduction and overview

Can I suggest that a general introduction to the planets is provided. Or is there a reason why this has not been done already? This could go just before the planets are listed - or in the Formation and evolution section - or the Formation and evolution section, together with a general introduction, could go just before where the planets are listed. I suggest that this could include an explanation of how (and why):

1. The temperature of planets drops with distance from the Sun (obvious!)

2. The chemical composition of planets varies with distance from the Sun (less obvious)

3. Orbital period increases with distance from the Sun.

4. Spacing of orbits increases with distance from the Sun.

5. Mass of planets increases then tails off with distance from the Sun.

As all these properties are a consequence of the mode of Formation and evolution of the solar system then that explanation could be integrated into such a section. Or should such details only go in the separate Planet article? Any comments? --Tediouspedant (talk) 23:48, 2 March 2010 (UTC)

The definition of planet is discussed in the terminology section. Points 3 and 4 are discussed in the Structure section. The relative masses of the planets are discussed in the inner and outer planets section. Point 1 might be worth mentioning, and I've been pondering whether and how to introduce the composition gradient (which is tied to temperature) into the structure section. Serendi^podous 08:32, 3 March 2010 (UTC)

When was the planet naming convention adopted?

In the article there is no mention about when the current Roman names were assigned to the planets, and this info is not included even in each individual planet article.

For example, Saturn was named after a Roman god, but did the Romans assign the god name to the planet in their time as well? Did Galileo call it "Saturn"? Since when was the planet naming convention adopted?

Thanks John Hyams (talk) 02:06, 12 March 2010 (UTC)

It was adopted by the Romans. It spread through Europe with the Roman Empire. Since all academic correspondence in Europe til the end of the Renassance was in Latin, there was no need to change the names. See: Planet#Mythology. Serendi^podous 05:50, 12 March 2010 (UTC)

It's not a convention. Mongolians and Tibetan don't use the Roman names for planets. The Sanskrit names are different too. Gantuya eng (talk) 08:05, 12 March 2010 (UTC)

Thanks Serendipodous. To make it clearer in the Planet article, I have changed the heading name to: Planet#Mythology_and_planet_naming (easier to find the information this way) John Hyams (talk) 13:24, 12 March 2010 (UTC)

"Heimdall"?

Surfing through the various language versions of "Solar System" and their discussions, I've found out that there is a certain uncertainty whether "Solar system" means anyone of them or just ours. My question: Has there been a discussion on this theme yet; and if not, would the term "Heimdall" for our "home world" be acceptable? Hellsepp 18:16, 1 May 2010 (UTC)