Bio-evolutionary Hypothesis for Absence of Green or Purple Stars
Take the evolutionary approach, and explain it by narrow spectra of survival-critical (evolutionarilyy rewarding) plants spectra due to narrow-spectrum chlorophyll and retinal.
So, various sources explain that human eyes have evolved to view yellow and green radiation , presumably because our Sun emits radiation primarily in those wavelengths, but that, perhaps is not a full story.
Here is a hypothesis I just thought of, that I had not known before:
- Animals must have evolved specific sensitivity to chlorophyll green, because plants are a source of food, and so, we had evolutionary pressure to evolved sensitivity to very specific wavelength of green color.
- Regarding the absence of purple stars, according to the Purple Earth Hypothesis, photosynthetic life forms of early Earth were retinal-based rather than chlorophyll-based, so early animals must have evolved the narrow-spectrum purple due to the same kind of evolutionary pressure.
What that would imply, is that we don't see green or purple stars not because they don't exist, but because of both biochemical and perhaps even neurological adaptions for narrow chlorophyl/retinal spectra. If these reasons are neurological more than biochemical, then one could say that we don't see green or purple stars because of psycho-optical illusion, similar to the hollow face illusion (rotating mask illusion), and say that green and purple stars do exist, we just don't see them the way we should, our eyes are biased.
This is an idea of a scientific hypothesis with an explanatory power to the question: "Why we don't see green or purple stars?"