I learned recently that my eyes are blue only in the sense that the sky and the ocean are blue. That is, they aren’t really. There’s a spot towards the front of the iris that, for most people, holds a bit of brown or other color of pigment. This section of my eyes, apparently, has no pigment at all, which means that my eyes don’t have a color of their own.

Blue light to the rescue! In dipping a toe into this subject, let’s first pay a visit to my old friend Roy G. Biv. As many of you know, because you stayed awake during high school science class, Roy’s name is an anagram of the colors of the visible light spectrum: Red, Orange, Yellow, Green, Blue, Indigo, Violet.

Side note: Roy might be out of a job. I looked at Wikipedia’s version of the visible light spectrum and found this: Red, Orange, Yellow, Green. . .so far so good. However, next is “Cyan” (very pale swimming pool blue), then Blue, and lastly Violet. What happened to Indigo?

Either way, Blue is close to the short-wavelength end of the spectrum, and it’s this fact that allows it to go dancing around on barren landscapes like the sky, the surface of the ocean, or my pigment-challenged eyes.

When the white light (all wavelengths combined, that is) hits these pigment-free surfaces, most of the longer waves just power on through, looking for a more respectable excuse to refract. Blue, however, being short and stubby, is easily deflected, and thus bounces back at the eyes of the observers.

So, my eyes aren’t blue unless someone is looking at them. A tree falls in the forest. . .

The only question that remains, then, is what is Violet doing? Her wavelengths are even shorter than Blue’s. Shouldn’t my eyes be purple?

Light is a funny thing. Left unchallenged, it will apparently go on forever without change. There is a supernova that blew up twenty-one million years ago in a place we rather prosaically named the Pinwheel Galaxy and is just now sharing its light show with us.

Are things real if nobody sees them?

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For your further edification:

A new supernova is visible in the night sky right now | Space