For small creatures such as we the vastness is bearable only through love.

Extinction is the rule, survival is the exception.

Somewhere, something incredible is waiting to be known.

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

Where we have strong emotions, we're liable to fool ourselves.

I don't want to believe. I want to know.

 image quote by Carl Sagan

Somewhere, something incredible is waiting to be known.

It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring.

Our ancestors worshipped the Sun, and they were not that foolish. It makes sense to revere the Sun and the stars, for we are their children.

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

We make our world significant by the courage of our questions and by the depth of our answers.

If you want to make an apple pie from scratch, you must first create the universe.

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

 image quote by Carl Sagan

We can judge our progress by the courage of our question and the depth of our answers, our willingness to embrace what is true rather than what feels good.

Our species needs, and deserves, a citizenry with minds wide awake and a basic understanding of how the world works.

The universe seems neither benign nor hostile, merely indifferent.

If we like them, they're freedom fighters .

. . If we don't like them, they're terrorists. In the unlikely case we can't make up our minds, they're temporarily only guerrillas.

For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring.

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

I am often amazed at how much more capability and enthusiasm for science there is among elementary school youngsters than among college students.

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.

When you make the finding yourself - even if you're the last person on Earth to see the light - you'll never forget it.

Books tap the wisdom of our species -- the greatest minds, the best teachers -- from all over the world and from all our history. And they're patient.

In the fabric of space and in the nature of matter, as in a great work of art, there is, written small, the artist's signature.

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

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

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

I can find in my undergraduate classes, bright students who do not know that the stars rise and set at night, or even that the Sun is a star.

If we long to believe that the stars rise and set for us, that we are the reason there is a Universe, does science do us a disservice in deflating our conceits?

All of the books in the world contain no more information than is broadcast as video in a single large American city in a single year. Not all bits have equal value.

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 imaginable: staying alive... If our long-term survival is at stake, we have a basic responsibility to our species to venture to other worlds.

In science it often happens that scientists say, 'You know that's a really good argument; my position is mistaken,' and then they would actually change their minds and you never hear that old view from them again. They really do it. It doesn't happen as often as it should, because scientists are human and change is sometimes painful. But it happens every day. I cannot recall the last time something like that happened in politics or religion.

Science is not only compatible with spirituality; it is a profound source of spirituality.

The boundary between space and the earth is purely arbitrary.

And I'll probably always be interested in this planet - it's my favorite.

Most of the people that I deal with are human. So I've had a lot of experience with that.

I've written a number of books that have to do with the evolution of humans, human intelligence, human emotions.

You probably don't need more weapons than what's required to destroy every city on earth. There's only 2,300 cities. So, the United States, by that criteria, only needs 2,300 nuclear weapons - well, we've got more than 25,000!

The professed function of the nuclear weapons on each side is to prevent the other side from using their nuclear weapons. If that's all it is, then we've gotta as: how many nuclear weapons do you need to do that?

It's been said that astronomy is a humbling and, I might add, a character-building experience.

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.

We are not without empathetic terror when we open Pascal's 'Pensees' and read, 'I am the great silent spaces between worlds.'

We start out a million years ago in a small community on some grassy plain;

we hunt animals, have children, and develop a rich social, sexual, and intellectual life, but we know almost nothing about our surroundings.

We hunger to understand, so we invent myths about how we imagine the world is constructed - and they're, of course, based upon what we know, which is ourselves and other animals. So we make up stories about how the world was hatched from a cosmic egg or created after the mating of cosmic deities or by some fiat of a powerful being.

Even these stars, which seem so numerous, are as sand, as dust - or less than dust - in the enormity of the space in which there is nothing.

Absence of evidence is not evidence of absence.

We're in very bad trouble if we don't understand the planet we're trying to save.

Today, we're still loaded down - and, to some extent, embarrassed - by ancient myths, but we respect them as part of the same impulse that has led to the modern, scientific kind of myth. But we now have the opportunity to discover, for the first time, the way the universe is in fact constructed as opposed to how we would wish it to be constructed.

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.

The dangers of not thinking clearly are much greater now than ever before.

It's not that there's something new in our way of thinking - it's that credulous and confused thinking can be much more lethal in ways it was never before.

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.

In our obscurity - in all this vastness - there is no hint that help will come from elsewhere to save us from ourselves. It is up to us.

We are the representatives of the cosmos;

we are an example of what hydrogen atoms can do, given 15 billion years of cosmic evolution.