This is our sun.

Radiolab: Cities

This is pretty damn interesting, if you ask me. If you have about an hour or so, and you'd otherwise be wasting your time on the Home Shopping Network--or whatever trash it is that you watch on t.v.-- listen to this.

"In this hour of Radiolab, we take to the street to ask what makes cities tick.

There's no scientific metric for measuring a city's personality. But step out on the sidewalk, and you can see and feel it. Two physicists explain one tidy mathematical formula that they believe holds the key to what drives a city. Yet math can't explain most of the human-scale details that make urban life unique. So we head out in search of what the numbers miss, and meet a reluctant city dweller, a man who's walked 700 feet below Manhattan, and a once-thriving community that's slipping away."