where is everyone?

0830, sitting in the airport. Still waiting for the coffee to sink in. I don't much like big crowds, so I'm a bit on the grumpy side this morning. I'm writing this offline to post later.

There's a fairly famous equation, the Drake equation, that tries to predict roughly how many advanced civilizations are hanging around in the galaxy at any given time. The basic idea is you take the number of stars, and multiply by the probabilities that a star has planets, that a planet can support life, that life will evolve, that evolved life will be sentient, that sentient life will forma civilization, and that the civilization will be able to communicate. No-one actually knows those probabilities, of course, and the estimates are all pretty low, but there are a huge number of stars in the galaxy. So, at the end, you get somewhere between two and a few thousand civilizations. SO then you have to ask how come no-one's dropped by to say "hello"? Or, at least, how come we're not picking up someone else's equivalent of Gilligan's Island or As the World Turns , 'cause we're sure as heck pumping those broadcasts to the rest of the galaxy right now. (Some time when you're in a meditative mood, flip through the broadcast channels and consider the impression we're making on the neighbors...)

Anyway, different people have different answers to the "were is everyone?" question. One of the most optimistic is Vernor Vinge's answer from Marooned in Real Time, where he borrows an idea from Freeman Dyson that technology improves at an increasing pace: if you chart the technology over time, you get this curve that goes up, up, up and eventually goes vertical. That point's called an asymptote. At the asymptote, our models break down, and you can't predict what happens afterwards.

I hope Vinge's right, but there's another theory that comes back to haunt me every so often. It has to do with the Ted Kaczynskis of the world. Every civilization has its crazy people. As technology gets better, so do the opportunities for the crazy people. In a paleolithic society, the best Ted could do is bop someone else on the head with his club or poke them with a pointy stick. In a 19th century civilization, Ted may be running around with a black powder bomb or maybe a stick of dynamite: same number of crazy people, more damage per person. In an early 21st century civilization, maybe Ted grabs a box cutter and hijacks a 747 into the World Trade Center. One crazy (or 19, as the case may be) kills a bunch of people right away and triggers one or two wars. What happens in a late 21st century civilization? A 22nd? Maybe the reason no-one's dropped by to say hello isn't that they're all at a great block party and didn't invite the wierdo neighbors who watch Fear Factor and leave trash in the yard. Maybe it's that every civilization has its crazies, and eventually its technology gets good enough for them to make everything go boom.