How Much Does it Cost to Blow Up a Planet?

A curious reader wrote in today with an odd and ominous inquiry--how much would it cost to power the laser of the Death Star? We're by no means the first ones to turn an analytical eye to everyone's favorite space opera, but outlandish questions like this are always a good opportunity to bring a bit of fun to mathematics.Fortunately, thanks to our legions of fellow nerds on the internet, most of the work's already been done for us: the good people at "StarDestroyer.net" went and calculated the ...