Hmmm..interesting CeeDee. But it beats me why anyone would want to come and live on our little planet. We are doomed ourselves. Overpopulation, choking the planet with our rubbish, and climate change will do for us. And that's without even mentioning the fact that various members of the human race are unable to live peacefully together and are continually fighting (mainly over religion.) If I were an alien I would steer very clear. But if, at some future stage, all of humankind has died out, and the Earth has healed herself, then this beautiful little world might seem very attractive to a passing alien.