One Year After Russia's Sky Exploded

[Today (or rather tonight due to time zone issues) is the one year anniversary of the asteroid impact over the Russian city of Chelyabinsk. What follows below is a retrospective on the event. Inspired by this, I also wrote a longform piece for Slate's Big Questions section, asking, "When Will the Earth Get Hit By Another Asteroid?"] At about 9:00 p.m. Mountain time a year ago, I was sitting at my desk wrapping up a long day of writing. I was about to get up to watch some TV when I saw a tweet co...