A blade of grass is a commonplace on Earth; it would be a miracle on Mars. Our descendants on Mars will know the value of a patch of green. And if a … - Carl Sagan

All three of Kepler’s laws of planetary motion can be derived from Newtonian principles. Kepler’s laws were empirical, based upon the painstaking observations of Tycho Brahe. Newton’s laws were theoretical, rather simple mathematical abstractions from which all of Tycho’s measurements could ultimately be derived. From these laws, Newton wrote with undisguised pride in the Principia, “I now demonstrate the frame of the System of the World.

We might have thought that the horrors of World War II and the Holocaust were enough to innoculate us against the toxins there revealed and unleashed. But our resistance quickly fades. A new generation gladly abandons its critical and skeptical faculties.

Our global civilisation is clearly on the edge of failure and the most important task it faces, preserving the lives and well-being of its citizens and the future habitability of the planet. But if we're willing to live with the growing likelihood of nuclear war shouldn't we also been willing to explore vigorously every possible means to prevent nuclear war. Shouldn't we consider in every nation major changes in the traditional ways of doing things, a fundamental restructuring of economic political social and religious institutions. We've reached a point where there can be no more special interests or special cases, nuclear arms threaten every person on the Earth. Fundamental changes in society are sometimes labelled impractical or contrary to human nature, as if nuclear war were practical or as if there's only one human nature. But fundamental changes can clearly be made, we're surrounded by them. In the last two centuries abject slavery which was with us for thousands of years has almost entirely been eliminated in a stirring worldwide revolution. Women, systematically mistreated for millennia are gradually gaining the political and economic power traditionally denied them and some wars of aggression have recently been stopped or curtailed because of a revulsion felt by the people in the aggressor nations. The old appeals to racial, sexual, and religious chauvinism and to rabid nationalist fervor are beginning not to work. A new consciousness is developing which sees the earth as a single organism and recognizes that an organism at war with itself is doomed. We are one planet. One of the great revelations of the age of space exploration is the image of the earth finite and lonely, somehow vulnerable, bearing the entire human species through the oceans of space and time.