[Nition]

This is something I've wondered about. People keep talking about how it's blue light that keeps you awake, but moonlight is pretty bluish. Why would humans have evolved to have that as the don't sleep wavelength?

[tylerhou]

Moonlight is white, just like how the sun is white. The moon = blue, sun = yellow connotations are mostly cultural.

[Nition]

Just looked it up. Apparently it's due to the Purkinje Effect, i.e. "The tendency for the peak luminance sensitivity of the human eye to shift toward the blue end of the color spectrum at low illumination levels."

[perl4ever]

I just googled it and apparently moonlight is actually redder (or yellower if you prefer) than sunlight.

Here is a thread with a graph of the spectrum: https://physics.stackexchange.com/questions/244922/why-does-...