The progress of science requires the growth of understanding in both directions, downward from the whole to the parts and upward from the parts to th… - Freeman Dyson

I have to clear away a few popular misconceptions about space as a habitat … It is generally considered that planets are important. Except for Earth, they are not. Mars is waterless, and the others are, for various reasons, basically inhospitable to man. It is generally considered that beyond the sun’s family of planets there is absolute emptiness extending for light-years until you come to another star. In fact, it is likely that the space around the solar system is populated by huge numbers of comets, small worlds a few miles in diameter, rich in water and the other chemicals essential to life.

Samuel Gompers was the founder and first president of the American Federation of Labor. He established in America the tradition of practical bargaining between labor and management which led to an era of growth and prosperity for labor unions. Now, seventy years after Gomper's death, the unions have dwindled, while his dreams-more books and fewer guns, more leisure and less greed, more schoolhouses and fewer jails-have been tacitly abandoned. In a society without social justice and with a free-market ideology, guns, greed, and jails are bound to win.

To give us room to explore the varieties of mind and body into which our genome can evolve, one planet is not enough.