 Nothing known to science can destroy a Type II. Ice ages and even a supernova cannot destroy a Type II civilization. So we should see them. We've looked in outer space for Type II civilizations, and so far we have not found any at all. Sorry about that. And one day I was in the London Planetarium giving a talk about this, and a little boy comes up to me, must be about 10 years old, and he says to me, Professor,