Why does light glow?

Question

another silly science homework question - can anyone help?

xD

Answer 1

It's a trick question.  Radio waves are light, do you see a glow around radios?  Microwaves are light, does your microwave in the kitchen glow?  The glow we see is the effect of the light on your retina, sending an electrical impulse to your brain which registers those frequencies as a "glow" of specific hues.

The light which "glows," to humans, is what we call the visible spectrum and is only a small range in the known spectrum of all light frequencies.  Many insects see into the ultraviolet, so to them, they would see different frequencies glow.

What we see as a glow is actually the emitted light from the object which our eyes can detect, as opposed to reflected light.

Answer 2

Magic.