Talk:Sunlight

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Spectral composition of sunlight at Earth's surface[edit]

The graph displayed as of 5/18/16 for the spectral composition at earth's surface needs improvement. Some of the lines are nearly invisible. A better explanation of the chart is also needed. It appears that ~460nm was chosen to yield an equal hight peak on the image and all spectra scaled to obtain this result, I assume this was to illustrate the relative composition of the light shifting. That rescaling and the reasoning behind it should be mentioned in the text. I think this motivation does justify the rescaling. If possible I'd like to see the intensity difference in a second plot. The 'x1.2, x16, x1.3...'. in the key on this plot gives a quantitative feel of the intensity differences, but the visual differences in an unscaled graph would convey it better to those who are less concerned about the exact number. However, having two graphs might take up too much space on the page. So perhaps the only change needed is better labeling and a better color scheme of the current graph. — Preceding unsigned comment added by 169.234.17.24 (talk) 19:47, 19 May 2016 (UTC)

Summary[edit]

I don't see why "A photon starting at the centre of the sun and changing direction every time it encounters a charged particle would take between 10 000 and 170 000 years to get to the surface." should be stated so early. That is not actually a significant part of the process by with sunlight is generated.

It's not even a meaningful part. Photons are just packets of electromagnetic energy obeying Bose-Einstein statistics and as such don't have identities. Particles absorb and emit photons but an emitted photon can't be identified with any specific absorbed photon; if it could it would obey Fermi-Dirac statistics. Putting this sentence right after the 8.3 minutes for sunlight to reach Earth implies an impossibly slow flow of energy from the center of the Sun to the surface. Vaughan Pratt (talk) 06:32, 27 July 2014 (UTC)

Luminance and retinal damage[edit]

I suggest that "burning glass" retinal damage be included in Effects on human health. It is largely the result of the high luminance of sunlight. This is easily observed in the increase of vision problems after solar eclipses, but it is much more common than that. Luminance is related to the light intensity at the sun's surface, unlike illuminance which is the intensity at the Earth's surface.

An other health effect may be macular degeneration due to cumulative exposure to blue light, but that may be too subtle to include here, at this time.

'Life on Earth' Section[edit]

At the end of the section, "peak oil" and "new urbanism" are given as examples of possible post-fossil-fuel scenarios. Both are in fact irrelevant examples regarding the topic. — Preceding unsigned comment added by 205.211.133.128 (talk) 13:43, 3 March 2015 (UTC)

Semi-protected edit request on 24 January 2016[edit]

Under the Heading "Calculations" the sentence which begins "where dn=1 on January 1; dn=2 on January 2; dn=32 on February 1,..." should read "...dn=3 on February 1..." Francis newman welder (talk) 13:11, 24 January 2016 (UTC)

Yes check.svg Done --allthefoxes (Talk) 16:49, 24 January 2016 (UTC)