Well, you knew that right? I've just finished watching the first episode of Space, the documentary series hosted by Sam Neil for the BBC on video. I don't mind as such that an actor, not a scientist was hosting it (though I prefer people with degrees). What irked me was that the science advisors were either ignored or didn't vet the script.
The blunder? The idea that a star will become a supernova when it exhausts all of the hydrogen. But where - in the core of course. But wait, if a star is only ever hot enough to burn hydrogen then it won't go supernova. As hydrogen is consumed as helium in the core, it cools and collapses. There is a helium flash as the star begins to produce carbon. This heat initiates hydrogen burning in a shell around the core. This shell isn't as bound as tightly as the core, and so expands as it is heated and cools - hence a red giant. Stars have to get all the way to iron, which is the most stable element before rebounding into a supernova (I hope I've got that 100% right, it's been a while since I did astrophysics). The take home: be wary of dumbed down science on the small screen.