1. The likelihood that alien technological civilizations occurring at the same time as ours is small. Planetary systems are of different ages within our galaxy. Neither a paleolithic culture nor a long dead alien civilization, let alone a primeval world inhabited only by bacteria, is going to send or receive any radio signals. In the 3.5 billion years life has been on our planet, we ourselves have only been capable of such communication for about 100 years. Finding Paleolithic cultures (like...