Lee is now 83, but has almost a boyish enthusiasm, and he speaks in the declamatory style of a guy with an idea he’s very eager to sell the rest of the world on. That idea: There could be life on other planets. Or there could have been life on other planets. That we may be the latest in our galaxy’s series of high-functioning civilizations that, for one reason or another, die out. (In our case, the reason, he says, will be humankind’s heedless ruination of the Earth’s environment.