Quotes by Carl Sagan

In college, in the early 1950s, I began to learn a little about how science works, the secrets of its great success, how rigorous the standards of evidence must be if we are really to know something is true, how many false starts and dead ends have plagued human thinking, how our biases can colour our interpretation of evidence, and how often belief systems widely held and supported by the political, religious and academic hierarchies turn out to be not just slightly in error, but grotesquely wrong.

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.

The near side of a galaxy is tens of thousands of light-years closer to us than the far side; thus we see the front as it was tens of thousands of years before the back. But typical events in galactic dynamics occupy tens of millions of years, so the error in thinking of an image of a galaxy as frozen in one moment of time is small.

Science is a way to call the bluff of those who only pretend to knowledge. It is a bulwark against mysticism, against superstition, against religion misapplied to where it has no business being.

When we look up at night and view the stars, everything we see is shinning because of distant nuclear fusion.

And you are made of a hundred trillion cells. We are, each of us, a multitude.

Consider again that dot [Earth]. Thats here. Thats home. Thats 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 aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species lived there - on a mote of dust suspended in a sunbeam.

These days there seems to be nowhere left to explore, at least on the land area of the Earth. Victims of their very success, the explorers now pretty much stay home.

On Titan the molecules that have been raining down like manna from heaven for the last 4 billion years might still be there largely unaltered deep-frozen awaiting the chemists from Earth

We must understand the Cosmos as it is and not confuse how it is with how we wish it to be.

The others would then fall silent and she would continue about doped gallium arsenide detectors, or the ethanol content of the galactic cloud W-3. The quantity of 200-proof alcohol in this single interstellar cloud was more than enough to maintain the present population of the Earth, if every adult were a dedicated alcoholic, for the age of the solar system. The tamada had appreciated the remark.

Science cuts two ways, of course; its products can be used for both good and evil. But theres no turning back from science.

We tend to hear much more about the splendors returned than the ships that brought them or the shipwrights. It has always been that way. Even those history books enamored of the voyages of Christopher Columbus do not tell much about the builders of the Nina the Pinta and the Santa Maria or about the principle of the caravel. These spacecraft their designers builders navigators and controllers are examples of what science and engineering set free for well-defined peaceful purposes can accomplish. Those scientists and engineers should be role models for an America seeking excellence and international competitiveness. They should be on our stamps.

Another glorious feature of many modern science museums is a movie theater showing IMAX or OMNIMAX films. In some cases the screen is ten stories tall and wraps around you. The Smithsonians National Air & Space Museu, the popular museum on Earth, has premiered in its Langley Theater some of the best of these films. To Fly brings a catch to my throat even after five or six viewings. Ive seen religious leaders of many denominations witness Blue Planet and be converted on the spot to the need to protect the Earths environment

The Man in the Moon is in fact a record of ancient catastrophes--most of which took place before humans, before mammals, and probably even before life arose on Earth. It is a characteristic conceit of our species to put a human face on random cosmic violence.

I try not to think with my gut. If Im serious about understanding the world, thinking with anything besides my brain, as tempting as that might be, is likely to get me in trouble. Really, its okay to reserve judgment until the evidence is in.

We have examined the universe in space and seen that we live on a mote of dust circling a humdrum star in the remotest corner of an obscure galaxy. And if we are a speck in the immensity of space, we also occupy an instant in the expanse of ages.

It is now almost possible to assign color combinations, based on the colors of clouds and sky, to every planet in the Solar System—from the sulfur-stained skies of Venus and the rusty skies of Mars to the aquamarine of Uranus and the hypnotic and unearthly blue of Neptune. Sacre-jaunt, sacre-rouge, sacre-vert. Perhaps they will one day adorn the flags of distant human outposts in the Solar System, in that time when the new frontiers are sweeping out from the Sun to the stars, and the explorers are surrounded by the endless black of space. Sacre-noir.

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

Significant change might require those who are now high in the hierarchy to move downward many steps. This seems to them undesirable and is resisted.