why sunsets have orange, red and purple, while purple is on the complete other end of the spectrum
In: Physics
[Turn that spectrum into a circle and you’ll see they are neighbors](https://decoart.com/blog/uploads/Color-Theory-Graphics-WHEEL34.jpg).
The purple is from blue scattered off particles in the upper atmosphere mixing with the normal reds and yellows. The red and yellow are due to the fact that the path of sunlight through the atmosphere is much longer at sunrise and sunset, and the atmosphere scatters blue-er light more than red and yellow.
[According to this site](https://spaceweatherarchive.com/2019/08/27/why-are-sunsets-turning-purple/), it’s due to volcanoes:
> Fine volcanic aerosols in the stratosphere scatter blue light which, when mixed with ordinary sunset red, produces a violet hue. The purple color is often preceded by a yellow arch hugging the horizon. As the sun sets, violet beams emerge from the yellow, overlapping to fill the western sky with a soft purple glow. High-quality pictures of the phenomenon often show horizontal bands cross-crossing the yellow arch. These bands are the volcanic gas.
Because of a phenomenon where molecules in the atmosphere scatter different wavelengths of light. When the sun is overhead the higher energy and shorter wavelength blue and violet wavelengths don’t have as far to travel to reach our eyes. We don’t see violet wavelengths well so that’s why we mainly see the blue ones. At sunrise and sunset the sun isn’t overhead but on the side resulting in a much greater distance for light waves to travel. The higher energy / shorter wavelength blue and violet light is scattered before it reaches your eyes. This allows your retinas to start picking up more of the yellows … Then orange … And finally red light. Each color having less energy but longer wavelengths allowing it to travel farther with less scattering. Night arises when no further light can make it to your eyes because it’s being absorbed by the Earth itself. Moonlight is the reflected blue and violet sunlight off of the Moon.
I can’t speak to the science of it & I also can only speak for LA, but sunsets in LA are the way they are because of the smog there. This was something I learned in school as a kid in the greater LA area.
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