Happy Fourth of July!

Today is a day worthy of recognition, a day which it is marvelously appropriate to celebrate with explosions of fireworks. Yes, that's right, today is the 950th anniversary of the supernova explosion which created the crab nebula! (Well, OK, it's actually the anniversary of the date on which the light from said explosion reached our planet. But, please, it's a holiday! Let us not quibble over details.)