Comic Book Questions Answered – where I answer whatever questions you folks might have about comic books (feel free to e-mail questions to me at brianc@cbr.com).

Reader Gerry D. wrote in to ask why Kryptonite has a negative effect on Superman when it is just made up of pieces of Superman's own home planet?

Really, the answer for almost everything in comic book history that seems like it doesn't necessarily make sense ultimately comes down to "because we said so." That's where these things begin and then sometimes writers will go back and try to come up with an explanation that fits the facts, but that is not the real reason why, the real reason is because someone decided that that was the case.

Kryptonite originally appeared on the Superman radio series in the early 1940s. Here's the hilarious thing about kryptonite. The whole idea is that they come from Krypton, right? Well, you see, for the first decade of his comic book existence, Superman did not even KNOW he was from Krypton! That's just logical enough, though, right? Later comic book stories (and films) have come up with ways to explain why Superman would learn his origins earlier in his life, but generally speaking, if you just land on earth as a baby in a rocketship, how in the world do you know where you cam from?

Not only that, but Superman's early years were very forward-thinking. There was not a whole lot of time spent on Superman's past. He did not even get a full origin until his 10th anniversary, when Bill Finger gave a full origin for the Man of Steel. A year later, Finger expanded that origin to allow Superman to learn the truth. This came after a piece of a meteorite was making Superman terribly weak when he was around it (it was used as the jewel in a Swami's head dress, so the Swami believed that it was his own mental powers that were causing Superman to weaken when he was around him). So Superman investigated the meteorites and then traced their path back in time (because, you know, Superman used to be able to travel back in time at the drop of a hat) and he learned that the meteorites came from his home planet, Krypton.

So the initial story is that, when Krypton exploded, the entire planet was fused together to form a new compound and that new compound was Kryptonite. So it was not Krypton itself, but rather what Krypton transformed into when it exploded. So it is not that Superman is having a problem with pieces of his own home planet, but that his home planet happened to be changed into something completely different from the explosion.

That idea (that Kryptonite was a compound formed from the explosion of the planet Krypton) was mostly kept consistent over the years. However, there were some interesting twists on the concept from time to time....

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Generally speaking, the key over the years became not just the planet's core being transformed into the new compound, but rather the radiation emitted from the explosion itself.

We saw this at play in Superman #157, where there was evidence of past crimes kept in a safe on Krypton. The safe survived the explosion of the planet and obviously it was not combined with the rest of the planet to form a new compound, since it was blown free of the planet and remained in the form of a safe, so what happened instead is that the radiation from the explosion altered its atomic composition and now the entire safe was made out of Kryptonite...

Therefore, any object that survived the destruction of Krypton would be transformed by the radiation into being made out of Kryptonite.

Post-Crisis, the history of Kryptonite was different, with a good deal of similarities with the original history of the compound. Now, what happened was that a terrorist attack on the planet Krypton resulted in the core of the planet being transformed into, well, Kryptontie. The radiation from this new core caused "The Green Death," which slowly killed off the people of Krypton while also slowly causing a chain reaction that led to the explosion of the planet...

So here, Kryptonite existed BEFORE the destruction of the planet, and in fact was the specific CAUSE of the destruction of the planet. Post-Crisis Superman stories also tried to limit the amount of Kryptonite available on Earth to just a small chunk that was lodged in Superman's rocketship when it escaped Krypton's explosion...

So there ya go, Gerry, that's the history of Kryptonite and why a piece of his own home planet can hurt Superman!

If anyone ELSE has a question about comic books for me, drop me a line at brianc@cbr.com!