Nathan

The New Yorker: Fact: "Let me say this, he said at another point. Im not sure we can solve the problem. I hope we can. I think we have a shot. I mean, it may be that were not going to solve global warming, the earth is going to become an ecological disaster, and, you know, somebody will visit in a few hundred million years and find there were some intelligent beings who lived here for a while, but they just couldnt handle the transition from being hunter-gatherers to high technology. Its certainly possible. Carl Sagan had an equation-the Drake equation-for how many intelligent species there are in the galaxy. He figured it out by saying, How many stars are there, how many planets are there around these stars, whats the probability that life will evolve on a planet, whats the probability if you have life evolve of having intelligent species evolve, and, once that happens, whats the average lifetime of a technological civilization? And that last one is the most sensitive number. If the average lifetime is about a hundred years, then probably, in the whole galaxy of four hundred billion stars, there are only a few that have intelligent civilizations. If the lifetime is several million years, then the galaxy is teeming with intelligent life. Its sort of interesting to look at it that way. And we dont know. We could go either way."