Forget Asking Why the Sky is Blue, Ask Why It’s Not Violet
Okay ya’ll, what’s the most cliched science-y question that you can imagine? As far as I can tell, it’s “why is the sky blue?” Too bad the entire concept of that question is wrong. Well, not really, but if one really understood the process of Rayleigh Scattering, the proces that makes the sky appear blue - it should, at least at first, seem like the sky appearing violet would make more sense.
When discussing the reason for the sky’s apparent blueness, there are basically two causes:
- Before white light from the sun reaches the surface of the Earth, the various light waves collide with atoms in the atmosphere, specifically nitrogen and oxygen atoms. Naturally, different frequencies (and therefore, different colors) of light are scattered differently. The higher frequencies, such as blue and violet, are much more easily scattered - therefore making the sky appear as if only high frequency light is bouncing around in it (Lord Rayleigh was the baller who discovered this - thus Rayleigh Scattering. Huzzah).
- Hold up Tyler, wait a minute, violet has a higher frequency than blue - so what gives? Shouldn’t it be scattered more? Remember, our eyes are just tools - what we see isn’t necessarily what exists - our eyes perceive the universe and try to explain it to our brains as easily as possible. Our eyes work better at frequencies near the middle of the spectrum (yellow and green), because of the composition of the eye (rods and cones). Since the color blue is closer to yellow or green than purple is, the sky we see appears blue. Technically, violet is more scattered than blue - but our eyes just aren’t as sensitive to it.