Why extraterrestrial civilizations may be exceedingly rare

There's been a lot of news lately about the estimate of habitable planets in our galaxy.  It sounds like there may be 40 billion planets in the habitable zones around their stars.  This is cool stuff!  The nearest one might be only  12 light years away. It's very tempting from this news, to conclude that … Continue reading Why extraterrestrial civilizations may be exceedingly rare