Talk:Diffusion damping/GA1

GA Review

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Hi, I'll be reviewing this article. This will take a few days, after which I will post my comments and either pass it, fail it, or put it on hold. Wronkiew (talk) 17:09, 16 April 2009 (UTC)

Some quick comments. Some images don't have captions. The Bible passages seems completely irrelevant, it simply mention winds used either literally or metaphorically/poetically. Unless there's significant theology (more than simply Isrealites considered winds to be of divine origins [they considered everything to be of divine origin, so winds are not special there]) being developped around them, it should IMO be removed (unless there's some weird Isrealite wind worship that was going on at some point in time). The recreation section could use some expansion. I'm giving these comments more in line with WP:PR than with WP:GAN, so the nominator can work on some things while waiting for Wronkiew to review and pass/fail this GAN.Headbomb {^ταλκ_{κοντριβς} – WP Physics} 04:06, 19 April 2009 (UTC)

Are you looking at the same article I'm looking at? What do Isrealites and divine winds have to do with diffusion damping? Also, sorry this review is taking so long. I expect it is going to take a few more days to a week. Wronkiew (talk) 04:11, 19 April 2009 (UTC)

I was indeed looking at the wrong article. I thought I was on the Talk:Wind/GA1 GAN. My bad. Headbomb {^ταλκ_{κοντριβς} – WP Physics} 04:19, 25 April 2009 (UTC)

GA review (see here for criteria)

1. It is reasonably well written.

   a (prose): b (MoS):

2. It is factually accurate and verifiable.

   a (references): b (citations to reliable sources): c (OR):

3. It is broad in its coverage.

   a (major aspects): b (focused):

4. It follows the neutral point of view policy.

   Fair representation without bias:

5. It is stable.

   No edit wars etc.:

6. It is illustrated by images, where possible and appropriate.

   a (images are tagged and non-free images have fair use rationales): b (appropriate use with suitable captions):

7. Overall:

   Pass/Fail:

Prose

• "Searches for anisotropies on a small scale are not as difficult as those on larger scales, partly because may employ ground-based telescopes and their results can be more easily predicted by current theoretical models." Seems like this sentence is missing a few words.

  Fixed: "partly because they may".

• "What affect the diffusion length are primarily the properties of the plasma in question: different sorts of plasma may experience different sorts of diffusion damping." Should this be "affects the diffusion"?

  Fixed: "effect".

• "Damping occurs at two different speeds on two different scales: on that lower than the mean free path of the photons, and on that greater than the mean free path, but less than the diffusion length." The sentence structure is very confusing, and I'm not sure if it's gramatically correct or not.

  Fixed: I rewrote this paragraph.

Lead section

• Jargon
  • Recombination

    Fixed: "epoch of recombination".

  • Gravitational redshifts

    Fixed: "the effects of gravity on electromagnetic radiation".

  • "Anisotropies" is defined but only used once in the lead section. Could the reference to it be eliminated?

    It's possible, but I wouldn't like it very much. I think a reader more familiar with the terminology of physics would not know what "density inequalities" refers to.

• Relative emphasis
  • The lead discusses diffusion damping's role in the formation of galaxies, but this is not explained later in the article.

    Fixed: added a section on this.

  • Same with electron diffusion.

    Fixed: I added a sentence on this to the "introduction" section. There's really not a lot that can be written.

  • Also, the second paragraph explains the relationship between Joseph Silk and diffusion damping, but this is not mentioned after the lead.

    Yeah, I don't know how much there is to say on this. I'll look further into it.

Words to avoid

• "Diffusion damping is thought to have taken place ..." Who thought this?

  Fixed: "took place".

• "Diffusion damping is thus said to ..."

  Fixed: "thus damps".

• "As diffusion damping works at this level, it is said to ..."

  Fixed: "scientists say it affects small angles". There's no more precision to be had, as the naming scheme is universal.

Jargon

• "Silk damping is not as significant in models of cosmological development which posit early isocurvature fluctuations, or fluctuations which do not require a constant ratio of baryons and photons." Not clear if this is describing two different kinds of fluctuations, or if this is defining isocurvature fluctuations.

  Fixed: turned the qualifying clause into a parenthetical one.

• What is Thomson scattering?

  Fixed: defined.

• What is a Newtonian gauge?

  Fixed? This is extremely hard to explain. I stated that $\Psi$ is related to General Relativity.

References

• Greg Gawiser was not one of the authors listed at http://www.physics.rutgers.edu/~gawiser/cmb_group.html . Did you mean Eric Gawiser?

  Fixed: I've removed this unnecessary reference.

• Which topic are you referencing from the Gawiser list?

  Fixed: I've removed this unnecessary reference.

Inline citations

• Is "soup" a quotation? If so, it needs to reference the source.

  Fixed: I italicised it, as it just needs to be recognised as a technical term.

• Same with many other quoted words, like "recombination", "decoupling", "damping", and so on. You might want to consider a different method of marking new terms, because quoting single words could be misinterpreted as editorializing. For example, standard practice is to italicize words that are referred to as a term for something. This could be applied to "called recombination".

  Fixed: I've changed them all to italics.

• The damping equation probably needs an inline reference.

  Fixed: included.

Most of this is very minor. I posted what I've done so far, but I still want to re-read the article to evaluate its breadth and level of detail. After that I'll put it on hold for improvements. Wronkiew (talk) 05:22, 22 April 2009 (UTC)

Breadth

• Overall a very accessible and complete treatment of the subject, considering the subject. However, I think the relationship between present-day galaxies and Silk scale/mass could use a more complete explanation.

Putting the assessment on hold for improvements. Wronkiew (talk) 05:26, 24 April 2009 (UTC)

• That's for the high quality review. I've addressed nearly everything. I'll finish this up ASAP. -- Rmrfstar (talk) 10:53, 28 April 2009 (UTC)

  Done! What do you think? -- Rmrfstar (talk) 03:26, 1 May 2009 (UTC)

Three issues remain. You more or less defined Newtonian gauge and Thomson scattering, but I think that wikilinks to the articles on these subjects would be much more helpful. Another issue is that the first sentence of "Galaxy formation" is very convoluted and may be grammatically incorrect. Finally, I think the first sentence of the second paragraph in "Diffusion length" has an error, it should be "diffusion length increases" or "diffusion lengths increase". Wronkiew (talk) 04:25, 1 May 2009 (UTC)

• I've fixed all of this too. I don't know why I didn't wikilink those terms before! -- Rmrfstar (talk) 11:18, 1 May 2009 (UTC)

Diffusion damping passes the GA criteria. Wronkiew (talk) 15:39, 1 May 2009 (UTC)