Wikipedia talk:Featured article candidates/Redshift

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[edit] Improvements

No problem. The introduction is already improved. By history, I think it would be nice to just mention in the intro when it was first postulated/described/observed to give us a sense for whether it was an ancient Greek idea or a more modern concept. Nothing major. I think that some of the concept issues occur when a separate idea is added at the end of other ideas. The white noise was more clear on second reading, but I think that a few word definition followed by white noise in parentheses might help.

• "At wavelengths longer than red (e.g. infrared, microwaves, and radio waves) redshifts shift the radiation away from the red. The corresponding shift to shorter wavelengths is called blue shift." - I think that simply moving blue shift up a line would get rid of any confusion as to what "corresponding" refers to. It doesn't refer to the sentence above, but rather an earlier one.

  Took care of this. --ScienceApologist 18:28, 18 August 2006 (UTC)

• "If a blueshift is seen associated with a strong gravitational field, it implies that the light is entering the field while redshifts imply light is leaving the field. This is the Einstein effect." - Since I don't understand enough about the effects that gravitational fields have on light (at this point in the article) to accurately interpret this sentence, it might be nice to have a couple more sentences setting it up. As it is, I don't understand the sentence and it is sorta tacked on to a paragraph that otherwise makes sense. Since there is a large section down below on the Einstein effect, it might be wise to just delete the comment.

  Took care of this. --ScienceApologist 18:43, 18 August 2006 (UTC)

• The white noise was more clear on second reading, but I think that a few word definition followed by white noise in parentheses might help.

  Took care of this. --ScienceApologist 18:29, 18 August 2006 (UTC)

• If you have to reference specific pages in a general physics/astrophysics book, then go ahead. If you can identify the original papers which brought up or proved the ideas in the paragraphs, that would be cool as well. As it is, it's not clear what in the list of references gives support to large parts of the article, including entire sections. I think that each section should at least have one reference! InvictaHOG 15:58, 18 August 2006 (UTC)

  Can you give me specific instances where references seem needed to you? As a professional, I have a hard time knowing what some people think need reference as opposed to what is general knowledge along the lines of "The Earth revolves around the sun". --ScienceApologist 18:45, 18 August 2006 (UTC)

• I would think this is to significant first (or early) papers. Eg. Einstein's prediction of gravitational redshift, Doppler broadening, the largest observed redshift, etc etc. --Iantresman 20:09, 18 August 2006 (UTC)

  Most of the papers you mention are already referenced in the article. The gravitational redshift was measured by Pound-Rebka and is referenced and the largest observed redshifts are all referenced. Doppler broadening as a feature was arrived at all at once as spectroscopy developed. There is no seminal paper that describes the Doppler Profile as independent from the Lorentzian profile or the Voigt profile. It's simply one of many phenomena that needs to be considered in order to adequately address the issues of line diagnostics. --ScienceApologist 23:38, 18 August 2006 (UTC)

• But Einstein's paper predicting gravitational redshift might be useful the paper referenced [1] doesn't seem to contain the prediction; and the paper showing the largest redshift measurement, that of the CMB at z = 1089, etc etc. --Iantresman 23:56, 18 August 2006 (UTC)

  COBE made the measurement of redshift when it accurately measured the temperature (there is a one-to-one relation). --ScienceApologist 01:22, 19 August 2006 (UTC)

I made improvements to the intro and defined white noise to deal with the first paragraph. --ScienceApologist 18:15, 18 August 2006 (UTC)