Talk:Sunlight

Luminance and retinal damage
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.

Upper limit to irradiance focused using mirrors?
Dividing the irradiance of 1050 W/m2 by the size of the Sun's disk in steradians gives an average radiance of 15.4 MW per square metre per steradian. (However, the radiance at the centre of the sun's disk is somewhat higher than the average over the whole disk due to limb darkening.) Multiplying this by π gives an upper limit to the irradiance which can be focused on a surface using mirrors: 48.5 MW/m2.

"Multiplying this by π gives" <-- Can someone clarify what this is attempting to calculate? It's apparently trying to sum all sunlight that a 1 square meter surface might have directed at it over a solid angle of π steradians. But π steradians isn't any special amount, so I'm not sure what that achieves. An entire sphere encompasses 4 π sr. Also, there's no citation, so difficult to follow up Gwideman (talk) 02:48, 1 July 2019 (UTC)

Solar spectrum between our ionosphere's critical frequency and infrared?
What does the sun emit between, say, 30MHz and 300GHz? — Preceding unsigned comment added by 85.240.218.46 (talk) 00:48, 23 August 2020 (UTC)

Structure and overlap
The article would need some structuring and focus. It duplicates it self and solar irradiance at several points and it is not clear where the article draws for it self the difference to solar irradiance and that article.

Maybe someone is more in it and has more time than me to get focus for this article? Nsae Comp (talk) 03:54, 8 July 2021 (UTC)

Messed up table
Yesterday I edited the table in "Intensity in the solar system" to make the column headings line up with their respective columns; MadeOfAtoms reverted those changes. I don't know all the ins and outs of table editing so it's possible I got it wrong in some way but the column headings lined up correctly when I made my changes, and now they're back to being wrong (unless perhaps things are displaying wrong on my machine). Rather than start a silly edit war I am making a note here. (The issue: the first sub-heading, "perihelion", should appear over the second column, not the first, and so on; there is no subhead over the first column.) atakdoug (talk) 20:44, 26 October 2021 (UTC)
 * For me, the table appeared with wrongly shifted column headings after your edits (a blank column header, and the others shifted one column too far to the right so "minimum" titles an empty column). Now it looks correct to me on Windows Firefox, Chrome, and Android Chrome. Maybe a browser compatibility issue? –MadeOfAtoms (talk) 01:42, 27 October 2021 (UTC)


 * Well that's it; the table displays incorrectly (still) in Firefox on a Mac, even with all extensions off, but correctly on Safari and Chrome. How odd. Firefox is up to date (v 93.0), and as I said, I tried with extensions off. I guess it's just me, but who knows why. atakdoug (talk) 03:32, 27 October 2021 (UTC)


 * , does your Mac Firefox show a problem with this small test table? Let's find the smallest table that induces the problem and try to understand it or pass it to experts, in case it's a WP-wide problem. –MadeOfAtoms (talk) 00:40, 31 October 2021 (UTC)
 * {| class="wikitable"

! rowspan=2 |Col 1 ! colspan=2 |Col 2 and 3 ! colspan=2 |Col 4 and 5
 * Col 2||Col 3
 * Col 4||Col 5
 * Col 4||Col 5


 * }

Citation Needed?
The article says that "sunlight at Earth's surface is around 52 to 55 percent infrared". However, there does not seem to be a source for that. Can anyone find something about that? 2601:603:B7F:F040:9E3:5A7A:3D48:F41E (talk) 18:02, 5 April 2023 (UTC)