Never having been one to read comic books I have a possibly silly
question regarding Superman's X-ray vision that a more knowlegeable
person might know the answer to.
How does Superman see anything with his X-ray vision considering that
under normal circumstances the X-ray flux (both ambient illumination and
emission from objects looked at) is negligible under everyday terrestrial
conditions? Does Superman have his own built-in X-ray source he uses to
illuminate what he is looking at or what? Or is 'X-ray vision' a
metaphor for some other perceptual mechanism? Inquiring minds want to
know.