Longer analysis of the Russian fireball

I was fascinated by the Russian fireball several days ago, partly because I've been concerned about both the space junk problem and the end-of-civilization scenarios that are posed by a larger impactor.  So this analysis was interesting of how big it was, where it came from, and how much energy was released.

Additional details on the large fireball event over Russia on February 15, 2013



Some great pictures taken by a frozen lake