The lifetime of a human being is measured by decades, the lifetime of the Sun is a hundred million times longer. Compared to a star, we are like mayflies, fleeting ephemeral creatures who live out their lives in the course of a single day.

To read is to voyage through time.

The suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge, and there's no place for it in the endeavor of science. We do not know beforehand where fundamental insights will arise from about our mysterious and lovely solar system. The history of our study of our solar system shows us clearly that accepted and conventional ideas are often wrong, and that fundamental insights can arise from the most unexpected sources.

The brain is like a muscle. When it is in use we feel very good. Understanding is joyous.

We are an intelligent species and the use of our intelligence quite properly gives us pleasure. In this respect the brain is like a muscle. When we think well, we feel good. Understanding is a kind of ecstasy.

One of the great commandments of science is: 'Mistrust arguments from authority.'

The cosmos is full beyond measure of elegant truths; of exquisite interrelationships; of the awesome machinery of nature.