Q: Why is it a capella? A: Because theoretical physicists don't use scientific instruments.
I simply had to share this. Tom Lehrer wrote some of the funniest songs ever while working as a maths professor. Charles Ives was an insurance salesman, Rimsky-Korsakov a naval officer, and Bruce Dickinson flies passenger jets when not fronting Iron Maiden. But this is the first time (AFAIK) that a quantum physicist has written and performed a version of Bohemian Rhapsody with lyrics illustrating a theory of quantum gravity.
Not only that - it rocks. Seriously - give it a listen.
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