I was with my friend and fellow astronomer Jesse Rogerson discussing the fantastic book from xkcd author Randall Munroe, called What if? We were talking about the brilliant analogy used by Munroe when talking about how big a supernova is. The questions asked was “Which of the following is brighter, in terms of the amount of energy delivered to your retina?” 1. A supernova, seen from 150 Million Kilometers, about as far as the Sun is from Earth. 2. The detonation of a Hydrogen Bomb, pressed against your eyeball. What a great question.  The answer, surprisingly, is the Supernova, which is...