First, x-rays happen to be at just the right frequency to a) get through your skin, and b) break the oxygen-hydrogen bonds in water and produce radicals in your body. Radicals in turn wreak havoc on your DNA. The result? Cell growth out of control (i.e. cancer). Sorry, Superman! Maybe using x-rays to see through the clothing of your beloved isn't such a great idea. The x-rays used at the dentist and doctor's office are used very sparingly, and even so it still isn't a good idea to get too much exposure. There's a good reason they drape that lead apron over you and then leave the room while you are being irradiated.There are also technical problems: since x-rays tend to pass through, rather than bounce off of, solid objects it's not clear how the x-rays emitted by Superman get back to his eyes. Ralston speculates that Superman could possibly use the Compton effect to detect x-ray scattering, but even that isn't very plausible. Read the entire article for her nice explanation of what you can and cannot do with x-rays.
Tags:Superman, x-ray vision