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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)
-- Kheider (talk) 14:07, 11 November 2014 (UTC)
Wavyinfinity (talk) 15:20, 11 November 2014 (UTC)
how planets form draft----------------------------------------------- i want to create a whole article on how planets form, but they won't let me because of this article.Aleks the science lover
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)
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)
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)
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)
This is in response to the statement, "(explanation) including the nearly circular and coplanar orbits of the planets." Yet the article via National Geographic clearly points to, "newly discovered star systems defy existing models of how planets form", and "theory has struck out", and "theory has implications not born out in reality."
The nebular hypothesis is falsified theory because it does not represent reality. I cannot see that being any clearer. Why is it not mentioned that exoplanets falsify this theory (hypothesis)? This has been known for over 4 years now, as the article was written Feb. 20, 2011. Wavyinfinity (talk) 12:42, 7 June 2015 (UTC)
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)
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)
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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)
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)
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)