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-Raskyl t1_j7fswxd wrote

Reply to comment by abeinszweidrei in Why are green and red laser pointers so cheap and available, but yellow ones not so much? by SurprisedPotato

Yellow also just doesn't travel as far. Which is why from far away, tress on mountains appear blue, not green.

Or at least that's what I've always heard.

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EverlastingM t1_j7fyhq0 wrote

Consumer lasers aren't going to be powerful or well calibrated enough for this to be an issue. The main phenomenon is Rayleigh scattering, the same thing that causes blue sky/red sunset, so red would travel farthest, and a hypothetical yellow would travel farther than green. There are some other less common factors like air pollution that could change how this plays out.

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_GD5_ t1_j7glxpn wrote

No, it’s because the atmosphere is scattering blue light between you and the mountain. Yellow light is unscattered.

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rcxdude t1_j7goyf1 wrote

Which is adding blue light, not removing yellow light (though the scattering also removes some blue light coming from the mountains: the scattered blue light from the much brighter sun more than makes up for it)

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