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You ever wonder why the small band of spectrum we can see (called visible light) is special? I mean almost all animals see in light ranges are are somewhere around here. I mean sure some can see a little farther into IR or UV but in general all animals see roughly around this same narrow band of frequencies in an otherwise infinite spectrum... So what is so special?
Its actually a quantum thing. Everything roughly around visible light and higher interacts with material by electrons jumping energy levels. However IR energy is absorbed by the bonds between molecules instead, which is why IR represents heat.
Basically visible light is right where these two modes intersect. Essentially they are the lowest energy part of the spectrum that is still high enough energy to interact primarily through changing energy levels of electrons. Essentially any more energy and it wont really get through the atmosphere as extreme UV is cut off.. any lower and it wouldnt be very effecieient cause most of the energy goes to heating the eye rather than seeing... So its right in that sweet spot.
@freemo @drnoble I think there's a more important reason: visible light includes the peak of the sun's output, and is a range in which the atmosphere is transparent.
We see with what is available.
(whether advanced life would have evolved on a planet with shorter wavelengths arriving at the surface is perhaps an interesting question - but that isn't where we live.)
@simon_on_energy @freemo @drnoble Another factor is that visible light travels through water. Eyes first evolved in aquatic animals, and they use wavelengths that can be seen through water.
If that were the case thenw e wouldnt be able to see red light very well as it has very minimal penetration depth in water.
So while Im sure this does play a role I'm not sure its as complete an answer as it sounds.
