Kryptonite was the invention of the radio show, and was created due to a format constraint. Whenever Bud Collyer
needed some time off, the writers could add kryptonite to the current storyline and have another actor moan in pain until Collyer returned from his holiday. See more
Up in the sky, look: It's a bird. It's a plane. It's Superman!
In the endless reaches of the universe, there once existed a planet known as Krypton, a planet that burned like a green star in the distant heavens. There, civilization was far advanced and it brought forth a race of "supermen," whose mental and physical powers were developed to the absolute peak of human perfection. But there came a day when giant quakes threatened to destroy Krypton forever. One of ...