In more than one respect, the exploring of the Solar System and homesteading other worlds constitutes the beginning, much more than the end, of history.

Your religion assumes that people are children and need a boogeyman so they'll behave. You want people to believe in God so they'll obey the law. That's the only means that occurs to you: a strict secular police force, and the threat of punishment by an all-seeing God for whatever the police overlook. You sell human beings short.

The Hindu religion is the only one of the world’s great faiths dedicated to the idea that the Cosmos itself undergoes an immense, indeed an infinite, number of deaths and rebirths. It is the only religion in which the time scales correspond, no doubt by accident, to those of modern scientific cosmology. Its cycles run from our ordinary day and night to a day and night of Brahma, 8.64 billion years long, longer than the age of the Earth or the Sun and about half the time since the Big Bang.

History is full of people who out of fear, or ignorance, or lust for power has destroyed knowledge of immeasurable value which truly belongs to us all. We must not let it happen again.

The desire to be connected with the cosmos reflects a profound reality, but we are connected; not in the trivial ways that astrology promises, but in the deepest ways.

Any civilization that doesn't develop space travel dies.

Chlorine is a deadly poison gas employed on European battlefields in World War I. Sodium is a corrosive metal which burns upon contact with water. Together they make a placid and unpoisonous material, table salt. Why each of these substances has the properties it does is a subject called chemistry.