Surprisingly quite good - gets one thinking about physics some and inconsistencies in semi-scientific fantasy stories.<p>Reminds me of an Eliezer Yudkowsky article talking about how fire and combustion couldn't "not work" in an alternate world that humans could survive in, because similar processes happen in our body. (Can't find that article right now unfortunately, it was quite good - it was referencing a fantasy story where fire didn't exist in a parallel world)<p>Anyway, paper is worth a read. People with an adept knowledge of physics will chuckle a little, but probably even better for people like me who haven't played with physics much - got me thinking about center of mass, density, inertia, etc. Interesting stuff. Recommended.