Colors of the world around us: Difference between revisions
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* '''The sky''' | * '''The sky''' | ||
: ...blue due to | : ...blue due to the nitrogen and oxygen. Their molecular size just happens to have a significant effect on blue (see [https://en.wikipedia.org/wiki/Rayleigh_scattering Rayleigh scattering]). | ||
: Since it's scattered, it's a diffuse effect throughout the whole sky. It's bluer when you look primarily at scattered light | : Since it's scattered, it's a diffuse effect throughout the whole sky. It's bluer when you look primarily at scattered light, as any other effects tend to be less pronounced. | ||
* '''Sunsets''' are red, and more so around the sun, actually for much the same reason | * '''Sunsets''' are red, and more so around the sun, and actually for much the same reason | ||
: that is, when you look at a sunset, you are looking at the horizon, seeing light that has passed through more atmosphere - so has more of its blue scattered out, leaving relatively more red | : that is, when you look at a sunset, you are looking at the horizon, seeing light that has passed through more atmosphere - so has more of its blue scattered out, leaving relatively more red | ||
: it helps that we're looking almost directly along the original light path; that's where the unscattered rays are visible | : it helps that we're looking almost directly along the original light path; that's the direction where mostly the unscattered rays are visible | ||
: pollution also helps - basically for more of the same effect | : pollution also helps - basically for more of the same effect | ||
With little background, it is quite sensible to theorize that the reason that the sky is blue might be refraction. | |||
It's not, though. | It's not, though. | ||
If it were, direction would matter a lot more than it does - we would see different colors depending on where we are, | If it were, direction would matter a lot ''more'' than it does - we would see different colors depending on where we are, | ||
and it would probably | and it would probably be almost entirely dark from behind us, opposite the sun. | ||
Yet it's blue everywhere, fairly evenly. | Yet it's blue everywhere, fairly evenly. | ||
And even photos from the space station reveal a blue sheen around earth. | And even photos from the space station reveal a blue sheen around earth. | ||
Also, sunlight makes it through apparently mostly undeterred. | Also, it's relevant that sunlight ''mostly'' makes it through apparently mostly undeterred. | ||
If it didn't, then sunlight couldn't be particularly white. | If it didn't, then sunlight couldn't be particularly white (that statement is actually messier than it seems, but let's not get into that right now). | ||
Also, direct sunlight and hard shadows probably wouldn't happen. | Also, direct sunlight and hard shadows probably wouldn't happen. | ||
Revision as of 20:38, 19 July 2023
✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.
The sky
On sunsets
See also
Might other planet's skies be other colors?
The sun
(TEMPORARILY ELSEWHERE)