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- he--scientist
- 26 points路1 day ago
- I think this might be more physiology than physics, and here's my non-expert understanding...
- There are (at least) two factors at play here. Number one is that our eyes are not super sensitive to short wavelength light compared to the rest of the spectrum. S-cones, which absorb short wavelength light, only account for around 2% of total cones compared to 32% for m-cones (green light) and 65% for l-cones (red). Here's a good visual representation of the difference:聽http://coffeeshopphysics.com/articles/2013-02/01_viruses_have_no_color/visible_spectrum.png
- Second, our lenses and corneas actually filter out progressively shorter wavelengths of light, which further handicaps our ability to perceive short wavelength light. So despite s-cones peak wavelength being around 430nm and violet light being around 410nm, there's an additional curve that must be subtracted from the short wavelength photons that actually everinteract with our s-cones.
- So you're right about the nature of Rayleigh's law, the sky should appear violet (same with blue eyes, which would be crazy!), but for that matter it "should" appear ultraviolet, we just don't perceive color well starting in the low end of the green range.
- Edit: typos
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- Spidge
- 20 points路1 day ago
- There's also the fact that the solar output peaks in the blue spectrum (randomly selected image as demonstration聽https://greensarawak.com/wp-content/uploads/2017/11/solar_radiation_spectrum.jpg). Look at the yellow line (spectrum outside the atmosphere) -the peak is in the blue and there's a huge drop just as it approaches the violet region which will pull a lot of that out.
- The red/green will also contribute - they may scatter less, but there's a much larger range that we can see below the blue (to the right) than above it - and as The--scientist said, we can see these colours better. This would balance out some of the violet that might otherwise be more dominant in appearance.
- From <https://www.reddit.com/r/askscience/comments/azrg4m/why_is_the_sky_not_violet/>