It’s easy to forget it, but much of the world is invisible to us. I don’t mean that in the sense of things being really tiny, or in any metaphorical way. No, most of the world is literally invisible.

That’s because what we call visible light is actually a tiny sliver of the much greater electromagnetic spectrum. The rainbow we see sits in the middle of a vast continuum of wavelengths, including everything from high energy gamma and ultraviolet radiation to much lower infrared and radio wa