Sooner or later, we will face a catastrophic threat from space. Of all the possible threats, only a gigantic asteroid hit can destroy the entire planet. If we prepare now, we better our odds of survival. The dinosaurs never knew what hit them.

I would like to believe that crop circles are evidence of visitation. But there have been too many people who have admitted to creating these crop circles, and too many people who have shown how to make one on TV programs, so I have my doubts.

It's risky to allow radiation to constantly go up into the atmosphere. The main criticism of this approach of entombing it is that it would cost too much, involve too many resources and people. But think of the cost of having all the crops impounded by the government, all the milk being thrown into the river, people's livelihoods destroyed.

For most of human history, we could only watch, like bystanders, the beautiful dance of Nature. But today, we are on the cusp of an epoch-making transition, from being passive observers of Nature to being active choreographers of Nature. The Age of Discovery in science is coming to a close, opening up an Age of Mastery.

Until computers and robots make quantum advances, they basically remain adding machines: capable only of doing things in which all the variables are controlled and predictable. Robots are bad at pattern recognition and certainly at common sense. That's why computers can beat humans in chess but can't have even a basic conversation with a six-year-old.

Chances are, when we meet intelligent life forms in outer space they're going to be descended from predators.

In general, the larger the breeding population, the slower the rate of evolution.