Carl Sagan

Extinction is the rule. Survival is the exception.

If you wish to make an apple pie from scratch, you must first invent the universe.

Imagination will often carry us to worlds that never were. But without it we go nowhere.

Science is a way of thinking much more than it is a body of knowledge.

We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology.

We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.

No other planet in the solar system is a suitable home for human beings; it's this world or nothing. That's a very powerful perception.

There is a wide, yawning black infinity. In every direction, the extension is endless; the sensation of depth is overwhelming. And the darkness is immortal. Where light exists, it is pure, blazing, fierce; but light exists almost nowhere, and the blackness itself is also pure and blazing and fierce.

We are the representatives of the cosmos; we are an example of what hydrogen atoms can do, given 15 billion years of cosmic evolution.

Who are we? We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people.

The universe is not required to be in perfect harmony with human ambition.

The Earth is a very small stage in a vast cosmic arena.

Our posturings, our imagined self-importance, the delusion that we have some privileged position in the universe, are challenged by this point of pale light. Our planet is a lonely speck in the great enveloping cosmic dark.

Absence of evidence is not evidence of absence.