We make our purpose.

Every one of us is, in the cosmic perspective, precious. If a human disagrees with you, let him live. In a hundred billion galaxies, you will not find another.

For thousands of years humans were oppressed— as some of us still are— by the notion that the universe is a marionette whose strings are pulled by a god or gods, unseen and inscrutable. Then,...

Humans — who enslave, castrate, experiment on, and fillet other animals — have had an understandable penchant for pretending animals do not feel pain. A sharp distinction between humans and ‘animals’ is essential if we...

If we long for our planet to be important, there is something we can do about it. We make our world significant by the courage of our questions and by the depth of our answers.

It’s a lazy Saturday afternoon, there’s a couple lying naked in bed reading Encyclopediea Brittannica to each other, and arguing about whether the Andromeda Galaxy is more ‘numinous’ than the Ressurection. Do they know how...

In all our searching, the only thing we’ve found that makes the emptiness bearable is each other.

Since, in the long run, every planetary civilization will be endangered by impacts from space, every surviving civilization is obliged to become spacefaring–not because of exploratory or romantic zeal, but for the most practical reason...

Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The...

A book is made from a tree. It is an assemblage of flat, flexible parts (still called “leaves”) imprinted with dark pigmented squiggles. One glance at it and you hear the voice of another person,...

Fireflies out on a warm summer’s night, seeing the urgent, flashing, yellow-white phosphorescence below them, go crazy with desire; moths cast to the winds an enchantment potion that draws the opposite sex, wings beating hurriedly,...

A galaxy is composed of gas and dust and stars – billions upon billions of stars. Every star may be a sun to someone.

Extinction is the rule. Survival is the exception.

The method of science is tried and true. It is not perfect, it’s just the best we have. And to abandon it, with its skeptical protocols, is the pathway to a dark age.

The total amount of energy from outside the solar system ever received by all the radio telescopes on the planet Earth is less than the energy of a single snowflake striking the ground.

A celibate clergy is an especially good idea, because it tends to suppress any hereditary propensity toward fanaticism.

Science is an attempt, largely successful, to understand the world, to get a grip on things, to get hold of ourselves, to steer a safe course. Microbiology and meteorology now explain what only a few...

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...

Pero ,por qué hemos de empeñarnos en pensar que el universo fue hecho para nosotros? ,Por qué resulta tan atractiva esa idea? ,Por qué seguimos alimentándola? ,Es tan precaria nuestra autoestima que no podemos conformarnos...

The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.

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 blade of grass...

Science is only a Latin word for knowledge

Any faith that admires truth, that strives to know God, must be brave enough to accommodate the universe.

In the vastness of space and the immensity of time, it is my joy to share a planet and an epoch with Annie.[Dedication to Sagan’s wife, Ann Druyan, in Cosmos]

Except for hydrogen, all the atoms that make each of us up—the iron in our blood, the calcium in our bones, the carbon in our brains—were manufactured in red giant stars thousands of light-years away...

People are not stupid. They believe things for reasons. The last way for skeptics to get the attention of bright, curious, intelligent people is to belittle or condescend or to show arrogance toward their beliefs.

It was difficult to hold Broca’s brain without wondering whether in some sense Broca was still in there—his wit, his skeptical mien, his abrupt gesticulations when he talked, his quiet and sentimental moments.

The idea that God is an oversized white male with a flowing beard, who sits in the sky and tallies the fall of every sparrow is ludicrous. But if by ‘God,’ one means the set...

What an astonishing thing a book is. It’s a flat object made from a tree with flexible parts on which are imprinted lots of funny dark squiggles. But one glance at it and you’re inside...

What a marvelous cooperative arrangement – plants and animals each inhaling each other’s exhalations, a kind of planet-wide mutual mouth-to-stoma resuscitation, the entire elegant cycle powered by a star 150 million kilometers away.

Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Many passengers would rather have stayed home.

Absence of evidence is not evidence of absence.

Our television signals leave this planet and go out into space…the signals spread out from the earth in spherical waves, a little like ripples in a pond. They travel at the speed of light, 186,000...

Nevertheless, (Jefferson) believed that the habit of skepticism is an essential prerequisite for responsible citizenship. He argued that the cost of education is trivial compared to the cost of ignorance, of leaving government to the...

The vast distances that separate the stars are providential. Beings and worlds are quarantined from one another. The quarantine is lifted only for those with sufficient self-knowledge and judgment to have safely traveled from star...

Al parecer anhelamos un privilegio, merecido no por nuestros esfuerzos, sino por nacimiento, digamos que por el mero hecho de ser humanos y de haber nacido en la Tierra. Podríamos llamarla la noción antropocéntrica, “centrada...

We are all star stuff.

The Cosmos extends, for all practical purposes, forever. After a brief sedentary hiatus, we are resuming our ancient nomadic way of life. Our remote descendants, safely arrayed on many worlds throughout the Solar System and...

As science advances, there seems to be less and less for God to do. It’s a big universe, of course, so He, She, or It, could be profitably employed in many places. But what has...

Present global culture is a kind of arrogant newcomer. It arrives on the planetary stage following four and a half billion years of other acts, and after looking about for a few thousand years declares...

At the heart of science is an essential tension between two seemingly contradictory attitueds–an openness to new ideas, no matter how bizarre or counterintuitive they may be, and the most ruthless skeptical scrutiny of all...

The astonishing fact is that similar mathematics applies so well to planets and to clocks. It needn’t have been this way. We didn’t impose it on the Universe. That’s the way the Universe is. If...

Observation: I can’t see a thing. Conclusion: Dinosaurs.

Sailors on a becalmed sea, we sense the stirring of a breeze.

If God is omnipotent and omniscient, why didn’t he start the universe out in the first place so it would come out the way he wants? Why’s he constantly repairing and complaining? No, there’s one...

The size and age of the Cosmos are beyond ordinary human understanding. Lost somewhere between immensity and eternity is our tiny planetary home. In a cosmic perspective, most human concerns seem insignificant, even petty. And...

The world is so exquisite, with so much love and moral depth, that there is no reason to deceive ourselves with pretty stories for which there’s little goodevidence.

No question; language can free us of feeling, or almost. Maybe that’s one of its functions – so we can understand the world without becoming entirely overwhelmed by it.

There were many women in the Soviet scientific community, proportionately more so than in the United States. But they tended to occupy menial middle-level positions, and male Soviet scientists, like their American counterparts, were puzzled...

Claims that cannot be tested, assertions immune to disproof are veridically worthless, whatever value the may have in inspiring us or in exciting our sense of wonder.