Talk:Nebular hypothesis

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Contents 1 "Solar nebula" vs. "pre-solar nebula" 1.1 Discussion post move to "Nebular hypothesis" 2 Links? 3 Links 4 Planetary Formation 5 solar features consistent with the nebular-hypothesis 6 Swedenborg 7 Rewrite of the article 8 Template:Star formation

[edit] "Solar nebula" vs. "pre-solar nebula"

I've been confused for a while by Wiki's usages of the term "solar nebula". From what I've been able to gather reading astronomical articles, the term "solar nebula" applies not to the original cloud but to the "residue" left over after the formation of the initial protostar that ultimately led to the formation of the planets. The initial nebular cloud pocket is called the "pre-solar nebula", while the great stellar nursery of which the solar nebula was a part is called the "giant molecular cloud". See this powerpoint presentation:

[1]

I think this article needs to be renamed "Pre-solar nebula" Serendipodous 11:14, 19 February 2007 (UTC)

The whole thing's a mess. I don't know what this was originally intended to be, but it's become an explanation of the process of planet formation - disc, planetesimals, jovian cores, giant impacts. Which is possibly why the nomenclature is highly inconsistent between articles. I intend to fill in the gaps and complete that explanation (but I've ended up doing other things for the time being). In my mind, this should then be re-named planet formation (as explained above); pre-solar nebula could become the 1st stage of this article (with a link to molecular cloud as the main article), or a separate one. Once I have added a lot to this article, I will push hard for the move. Spiral Wave 11:34, 19 February 2007 (UTC)

As a compromise, I'd be willing to accept this article become purely about the solar nebula, as a kind of special case of protoplanetary disc, since we know more about our own local conditions. But that would involve the creation of a new planet formation article, and most of sections 1.2 - 1.8 from here would be moved (or at least copied) over there. Spiral Wave 12:06, 19 February 2007 (UTC)

As a start to the cleanup, I've shifted the material in this article to planetary formation, created a link to planetary formation at protoplanetary disk, and created a stub article on the solar and presolar nebulae. It's not much but it's a start. Serendipodous 15:46, 19 February 2007 (UTC)

Yeah, I suppose it's better to get stuck in now than decide to move more concrete articles at a later date, after they've been heavily added to. I think this will simplify things in the long run. Spiral Wave 15:49, 19 February 2007 (UTC)

[edit] Discussion post move to "Nebular hypothesis"

The large article that used to be at this location has been moved for good or ill to "nebular hypothesis". The "Solar nebula" is a term referring to the nebula from which the Sun and the solar system both formed. The process by which this is thought to have happened is described in the nebular hypothesis article. This article, therefore, does not need expanding. It should not be a stub. It needs a short description, and a big fat link pointing to the nebular hypothesis article. Myrrhlin 21:53, 16 April 2007 (UTC)

The term "solar nebula" is generally applied to the "leftovers" after the formation of the Sun that formed the planets. The nebula out of which the Sun formed is called the "presolar nebula." Serendipodous 21:57, 16 April 2007 (UTC)

That is not correct, in my understanding. The references at the bottom of this page are not trustworthy, and in some respects demonstrably inaccurate. The textbooks I use are fairly consistent on this point of terminology. I would not be surprised, however, if you can find another convention. But I think Kant et al. who proposed the original nebular hypothesis were talking about the formation of the entire solar system, not just the planets. It does not make sense to talk about a collapsing, flattening, heating, spinning cloud, that will become the planets separate from the sun. They come from the same cloud. The disk where the planets form is called a protoplanetary disk. The "solar nebula" is not simply a protoplanetary disk. The solar nebula came BEFORE the protoplanetary disk.

Where did you learn that "solar nebula" does not include the proto-sun? Myrrhlin 22:21, 16 April 2007 (UTC)

Here, here, here, here, here, here, and here all give an estimate for the mass of the solar nebula as 0.1 the mass of the Sun. This would be ludicrous if the solar nebula also included the Sun. Serendipodous 07:06, 17 April 2007 (UTC)

As those references show, Serendipodous is correct, "solar nebula" refers to the nebula (really a disc) around the Sun, not the nebula from which it formed (which is the "presolar nebula"). The relevant paragraph needs correcting appropriately, but I don't want to start an edit war so I'll wait for any objections here before changing anything. Meanwhile, if anyone can come up with any evidence showing that solar nebula does actually (commonly) mean the precursor cloud, then that alone is reason to give them a separate article to planet formation/nebular hypothesis: so that the two different meanings can be explained and clarified, away from the nebular hypothesis argument. Mixing them all up together is a recipe for confusion. Spiral Wave 19:38, 22 April 2007 (UTC)

NOTE: an admin then moved the article back from nebular hypothesis to solar nebula without allowing further discussion on the matter. Serendipodous 06:47, 29 July 2007 (UTC)

[edit] Links?

What the heck is with that ALL CAPS link? It doesn't point to anything valid. I'm deleting it, but here's the original:

INJECTION OF RADIOACTIVE NUCLIDES FROM THE STELLAR SOURCE THAT TRIGGERED THE COLLAPSE OF THE PRESOLAR CLOUD CORE

--130.157.41.169 19:50, 7 March 2007 (UTC)

Link fixed. It mainly describes the theory that the presolar nebula began its collapse after being disturbed by a supernova. Serendipodous 20:59, 7 March 2007 (UTC)

[edit] Links

PS I would argue for removal of at least two of those external links. The summary for 9th-graders with group activity is quite inaccurate. In the PPT presentation linked, the author claims the collapse of the solar nebula was triggered by a supernova. While that is a possibility, its pure speculation. I've not seen any research to support this. Could just as likely (perhaps more so) have been a passing spiral density wave, or no particular cause. Myrrhlin 22:27, 16 April 2007 (UTC)

Fine by me. It's not like there are that many sources anyway. If you feel that they could be improved, go for it.Serendipodous 07:19, 17 April 2007 (UTC)

[edit] Planetary Formation

I noticed that the topic of 'Planetary formation' is linked to here. MegaHasher 00:19, 29 July 2007 (UTC)

Yeah. That's an issue. The fact is, and this is a point I've made dozens of times, the solar nebula is NOT the original cloud out of which the Solar System formed. That's called the pre-solar nebula. The Solar nebula is the residue left over after the Sun formed that ultimately formed the planets. Even though I provided eight scholarly references to that effect, people still refused to move the topic, and since the topic has already been moved, I can't do it without admin approval. Serendipodous 06:08, 29 July 2007 (UTC)

I also see other references with different usages, such as [2] and [3]. I don't have textbooks handy for additional checks. MegaHasher 01:11, 30 July 2007 (UTC)

[edit] solar features consistent with the nebular-hypothesis

the planets are all in the ecliptic (except for pluto), they all have right-hand revolution around sun, they all have right-hand rotation, including sun, excepting Uranus and Earth (the 90 and 23 degree offset is believed to be due to impacts (moon in earth's case)

Do the planets' moons also have mostly right-hand rotations & revolutions on the ecliptic ? These would mostly be captured planitesimals out of the accretion disk, perhaps with the random & rare capture of an object which was previously dislodged out of its circular ecliptic orbit, and then possibly impacting, or being captured in an off-ecliptic orbit, by another planet ?

Does the Milky-way also have a right-hand rotation ? Is it a possible source of the angular momentum in a pre-solar nebula ? Do most stars also have a right-hand rotation (if this is observable) ?

[edit] Swedenborg

The Swedenborg claim is referenced only to an original work of Swedenborg. I have no access to it and there is an obvious worry that this is an unpublished synthesis. There is no mention of Swedenborg in the (2001) Encyclopaedia Britannica article on "Solar system:Origin of the solar system" though it mentions Kant and Laplace, going so far as to talk about the "Kant-Laplace nebular hypothesis". Can we have a citation to some secondary interpretation please? Cutler 23:18, 24 August 2007 (UTC)

[4] Go here if you want more references. Look at section D and the following.

Jasonschnarr 18:04, 25 October 2007 (UTC)

[edit] Rewrite of the article

I prepared this text, which I want to insert into the article. Talk:Uranus/new_subpage. Ruslik 11:26, 24 October 2007 (UTC)

[edit] Template:Star formation

I would like to suggest adding this template to help interlink all of the articles based on star formation. I would do it myself but I don't know how to without upsetting the formatting of the article.Coffeeassured (talk) 00:23, 13 April 2008 (UTC)

I will probably add it soon. Ruslik (talk) 08:16, 13 April 2008 (UTC)