Bill Gosper:
But can someone explain the multiplicity of bangs that characterize these bolides? Is it just sonic booms from individual fragments on different trajectories, or maybe similar trajectories with different speeds?
Here is what Warren Murray (a co-editor for The Guardian) said about this: "Put simply, a body going supersonic creates multiple shock waves and therefore can make multiple booms: one in front, one behind, plus others potentially. This partly depends on its shape, changes in trajectory etc. The space shuttle was always known for two booms. Also, consider how very loud those booms in Russia would have been, and the fact that echoes off the sides of mountains etc would have in turn travelled a very long way and been heard some time afterwards."
Energy must be fairly cheap in Chelyabinsk to justify so many single pane windows in such a frigid climate. A harbinger of prosperity.
On the other hand, they effectively halved the cost of replacement. ;)