Talk:Nebular hypothesis

message: Why is there no mention of exoplanets? Surely the 3,524 exoplanets that have been found have some sort of significance inside of a model which claims to explain their existence? Or is it that the 3,524 exoplanets found defy the nebular hypothesis so there can be no mention of them made here? Elephant in the room Wavyinfinity (talk) 21:39, 10 November 2014 (UTC)
replies: text: Exoplanets are simply not as well studied as our own system. It difficult to know the precise mass and diameter of most of these exo-planets, much less where and how big their various equivalents of the asteroid belt(s) and Kuiper belt(s) are (might be). We simply need to know more. We also need to better understand planetary migration as in the case of the nice model. -- Kheider (talk) 22:10, 10 November 2014 (UTC)
replies: text: The Nice model does not solve the main issues. How did the planets lose their angular momentum? How do 1cm sized particles clump together? How do rocks and minerals form absent the activation energy required for non-spontaneous chemical combination reactions? How do gas giants form from a quickly disappearing disk? It appears to me that the Nice model does not solve anything, but only adds more problems, because now we have to explain how stable orbits become unstable just so they be arranged in the way we see them. Wavyinfinity (talk) 12:57, 11 November 2014 (UTC)

text: I would not worry about it. This nebular hypothesis page is only going to serve as a footnote in history, similar to the flat earth page. Oh and I went ahead and updated that count to make the matter more pressing, I hope you don't mind it bulwarks your point.Trilliant (talk) 13:33, 20 June 2016 (UTC)
replies: text:  These are bad explanations as they completely ignore both chemistry and thermodynamics (see below). Why are chemistry and phase transitions ignored?
Wavyinfinity (talk) 15:20, 11 November 2014 (UTC)
replies: text: Chemistry and hydrated minerals on protoplanets such as 4 Vesta are a major area of planetary study. -- Kheider (talk) 16:10, 11 November 2014 (UTC)
replies: text:  So why is chemistry and thermodynamics not mentioned at all on this page, regardless if all the objects in the solar system are comprised of elements and the compounds they form? As well, where in the nebular hypothesis is it mentioned why objects are still hot even 4.5 billion years after they formed and some are not? This article reads like 18th century conjecture and needs to be updated. Wavyinfinity (talk) 20:31, 21 July 2015 (UTC)
thread_title:  Exoplanets 

message: Why is there no mention of chemistry? Are not asteroids comprised of rocks/minerals? The gravitational potential energy of a large asteroid does not contain the activation energy to synthesize rocks (non-spontaneous chemical reactions) in outer space. Why is this also completely ignored? Or am I wrong to consider science as a multidisciplinary subject? Wavyinfinity (talk) 12:09, 11 November 2014 (UTC)
replies: text:  It literally feels as if this model was invented before chemistry became an actual science. I would suggest placing a tag on this article stating that it is severely out of date and does not reflect modern science. Wavyinfinity (talk) 15:47, 11 November 2014 (UTC)
replies: text: I suggest we keep handwaving and pseudoscience out of Wikipedia. -- Kheider (talk) 16:10, 11 November 2014 (UTC)
replies: text: You haven't answered the question. Why in this entire article the arguably most important physical science ignored?Wavyinfinity (talk) 20:35, 11 November 2014 (UTC)
thread_title:  Chemistry 

message: Why is there no mention of thermodynamics? You know, simple phase transitions of matter, plasma (physics) becomes gas, gas becomes solid/liquid matter and vice versa? The writers of this article have completely avoided talk of thermodynamics, regardless if the objects being mentioned are literally made of plasma, gas, liquids and solids. That is like talking of storms but not mentioning rain or winds. Wavyinfinity (talk) 12:17, 11 November 2014 (UTC)
thread_title:  Thermodynamics 

message: The text says:
"Initially very hot, the disk later cools in what is known as the..."
The temperature in accretion disks in all phases of their evolution has complex spatial gradients. They are hot (up to 2500 K) near the star and warmer (few 100 K) on their surface and the outer accretion shock, but there are large regions even in young accretion disks with temperatures of a few 10 K only. Hence the current sentence is wrong, and I would remove it.  — Preceding unsigned comment added by 90.18.196.171 (talk) 09:22, 26 August 2023 (UTC)
thread_title:  Accretion disks claimed to be very hot 

message: The forth state of matter is not mentioned in this entire article, even though all hot stars are comprised of it. You do not have to believe me, read the entire article! The words plasma or ionization or recombination are not mentioned anywhere. The most abundant observed state of matter in the entire universe is ignored. Why?Wavyinfinity (talk) 21:27, 11 November 2014 (UTC)
thread_title:  Plasma 

message: A couple of papers describing new models for the formation of planetesimals. New Paradigms For Asteroid Formation, The multifaceted planetesimal formation process. 
And another which integrates accretion, migration and recent models of protoplanetary discs. The growth of planets by pebble accretion in evolving protoplanetary discs
I've written articles for streaming instability and pebble accretion and am now looking at how and where to integrate parts of these topics into articles like this one. Suggestions welcome. Agmartin (talk) 19:19, 7 March 2016 (UTC)
thread_title:  Recent Research 

message: Subsection 2.2 Problems and criticism looks like it needs work. The tone, whether intentional or not, smacks of Intelligent design (a form of creationism). For example: "The formation of planetesimals is the biggest unsolved problem in the nebular disk model. How 1 cm sized particles coalesce into 1 km planetesimals is a mystery." Our own article Planetesimal does a pretty good job of summarizing what scientists have come up with. Of course there are kinks to be worked out, but it is not "a mystery."
Next: "The formation of giant planets is another unsolved problem. Current theories are unable to explain how their cores can form fast enough to accumulate significant amounts of gas from the quickly disappearing protoplanetary disk." Over the last few weeks, I've read a bunch of research papers on this. There are apparently quite a few mechanisms by which this could have occurred. It's just a matter of reaching a consensus on which one is the most likely, or if it was a combination of mechanisms.
The last paragraph in this subsection, which quotes Newton as saying "the growth of new systems out of old ones, without the mediation of a Divine power...is absurd" should be moved to the history section.
Finally, the title of this subsection should be changed to something like "Current issues." The phrases "unsolved problem" and "unsolved mystery" stand out like sore thumbs. Zyxwv99 (talk) 22:51, 25 March 2016 (UTC)
replies: text: The formation of planetesimals is discussed in the 'Protoplanetary disks' section with a couple of proposed solutions mentioned. Perhaps a few brief sentences should be added mentioning these in the 'current issues' subsection as has been done with angular momentum. The migration of the planets is also an evolving field. In addition to the Grand Tack, I have seen planet traps, where the structure of disk causes migration to halt; and things like co-rotational torques, heating torques discussed recently. Agmartin (talk) 21:10, 26 March 2016 (UTC)
thread_title:  Subsection "Problems and criticism" needs work 

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thread_title:  External links modified 

message: The NGC 2174 or Monkey Head Nebula article states 'The nebula may have formed through hierarchical collapse.' Should 'hierarchical collapse' link to 'Nebular hypothesis' please, or is there a better target? John a s (talk) 15:33, 17 April 2019 (UTC)
replies: text: This is a possible alternative https://en.wikipedia.org/wiki/Star_formation#Cloud_collapse Agmartin (talk) 16:41, 17 April 2019 (UTC)
replies: text: Thanks! 19:00, 17 April 2019 (UTC)
thread_title:  Hierarchical collapse 

message: I'm a new editor and don't know a lot about this topic, but wanted to point out that the introduction is not pleasant to read- I think it could be condensed a little bit and some parts reworded. E.g. I was especially thrown off by the sentence "They considered that sun was surrounded by a solar nebula containing mostly the hydrogen and helium along with what may be termed as dust" ; I had to go back and re-read to figure out the antecedent of "they" and "that sun" was confusing. Maybe switch to "They considered that the early sun was surrounded.." or "Scientists considered that the early sun was surrounded.."? 
Fluffystat (talk) 22:47, 25 June 2020 (UTC)
thread_title:  General Editing Note 

message: Why this insertion in the introduction? 
https://en.wikipedia.org/w/index.php?title=Nebular_hypothesis&type=revision&diff=921654431&oldid=921653936
It is not an article on Chamberlin theory, moreover the next sentence after this theory is "It is the most widely accepted model" which is ambigious.
2A01:E0A:589:4E20:2927:EA5F:D928:3D3 (talk) 17:31, 2 July 2020 (UTC)
thread_title:  Introduction