10 Disturbing Mysteries Superheroes Couldn't Solve

Kryptonite was first introduced in 1943 on the Superman radio show for a rather unique reason. The actor who gave voice to the Man of Steel wanted to take a vacation, but the show must go on, so they were left with a strange choice.

They introduced Kryptonite as a way of making Superman sick. For the weeklong vacation, another actor moaned and made distressing sounds to pretend Superman was there but wasn't doing too well. It was then introduced in 1949's Superman #61 in a non-green variety with the standard green rock appearing in 1951's Action Comics #161.

It's clear that Kryptonite hurts Superman, but does anyone actually know why this is the case? Why would a rock from his homeworld cause him immeasurable pain, and deprive him of his superpowers? After all, wouldn't a Kryptonian have evolved on Krypton, and be immune to the planet's ill effects?

There have been numerous theories put forth about this over the years, and while they are all pretty good, the comics haven't confirmed anything. Kryptonite remains more of a reverse deus ex machina or a MacGuffin meant to drive the story in one way or another, and for whatever reason, it's never really been explained.