Light, as we know, is a form of electromagnetic radiation. Colors of light, in turn, correspond to certain wavelengths on this electromagnetic spectrum. It's amazing to realize that, just by looking at the spectra of an object's light, we can glean so much insight into distant, exotic worlds that are trillions of miles away from our home planet.
Traditionally, here on Earth, most color comes from pigments and how our eyes interact with them, not wavelengths of light. In short, pigments alter the "color" of light that we perceive because they absorb certain wavelengths. However, not all colors come from pigments. There are a few notable exceptions. Perhaps the most beautiful are Iridescent creatures, like the blue morpho butterfly. Naturally, this incredible creature's name comes from its blue coloring, but to make a long explanation short, it's not blue at all.. Not really, anyways. Rather, its hue comes from something called "structural coloring," whereby color is the result of interactions between physical structures, light and our eyes (diffraction and dispersion vs reflection and absorption).
There's definitely an evolutionary advantage to this trickery. Unlike using pigments, deriving color from simple physics allows creatures like this to essentially hide in plain site when light strikes from certain angles, Learn more in the video below:
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