of geometry and optics。 The Sun emits its radiation equitably in all directions。 Had the picture been taken a little earlier or a little later； there would have been no sunbeam highlighting the Earth。
And why that cerulean color？ The blue es partly from the sea； partly from the sky。 While water in a glass is transparent； It absorbs slightly more red light than blue。 If you have tens of meters of the stuff or more； the red light is absorbed out and what gets reflected back to space is mainly blue。 In the same way； a short line of sight through air seems perfectly transparent。 Nevertheless—something Leonardo da Vinci excelled at portraying—the more distant the object； the bluer it seems。 Why？ Because the air scatters blue light around much better than it does red。 So the bluish cast of this dot es from its thick but transparent atmosphere and its deep oceans of liquid water。 And the white？ The Earth on an average day is about half covered with white water clouds。
We can explain the wan blueness of this little world because we know it well。 Whether an alien scientist newly arrived at the outskirts of our solar system could reliably deduce oceans and clouds and a thickish atmosphere is less certain。 Neptune； for instance； is blue； but chiefly for different reasons。 From this distant vantage point； the Earth might not seem of any particular interest。
But for us； it's different。 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 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。
The Earth is a very small stage in a vast cosmic arena。 Think of the rivers of blood spilled by all those generals and emperors so that； in glory and triumph； they could bee momentary masters of a fraction of a dot。 Think of the endless visited by the inhabitants of one corner of this pixel the scarcely distinguishable inhabitants of some other corner； how frequent their misunderstandings； how eager they are to kill one another； how fervent their hatreds。
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。 In our obscurity； in all this vastness； there is no hint that help will e from elsewhere to save us from ourselves。
The Earth is the only world known so far to harbor life。 There is nowhere else； at least in the near future； to which our species could migrate。 Visit； yes。 Settle； not yet。 Like it or not； for the moment the Earth is where we make our stand。
It has been said that astronomy is a humbling and character…building experience。 There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world。 To me； it underscores our responsibility to deal more kindly with one another； and to preserve and cherish the pale blue dot； the only home we've ever known。
CHAPTER 2 ABBERATIONS OF LIGHT
If man were taken away from the world； the rest would seem to be all astray； without aim or purpose 。 。 。 and to be leading to nothing。
—FRANCIS BACON； WISDOM OF THE ANCIENTS （1619）
Ann Druyan suggests an experiment： Look back again at the pale blue dot of the preceding chapter。 Take a good long look at it。 Stare at the dot for any length of time and then try to convince yourself that God created the whole Universe for one of the 10 million or so species of life that inhabit that speck of dust。 Now take it a step further： Imagine that everything was made just for a single shade of that species； or gender； or ethnic or religious subdivision。 If this doesn't strike you as unlikely； pick another dot。 Imagine it to be inhabited by a different form of intelligent life。 They； too； cherish the notion of a God who has created everything for their benefit。 How seriously do you take their claim？
“SEE THAT STAR？〃 〃You mean the bright red one？〃 his daughter asks in return。 〃Yes。 You know； it might not be there anymore。 It might be gone by now—exploded or something。 Its light is still crossing space； just reaching our eyes now。 But we don't see it as it is。 We see it as it was。〃
Many people experience a stirring sense of wonder when they first confront this simple truth。 Why？ Why should it be so pelling？ On our little world light travels； for all practical purposes； instantaneously。 If a lightbulb is glowing； then of course it's physically where we see it； shining away。 We reach out our hand and touch it： It's there all right； and unpleasantly hot。 If the filament fails； then the light goes out。 We don't see it in the same place； glowing； illuminating the room years after the bulb breaks and it's removed from its socket。 The very notion seems nonsensical。 But if we're far enough away； an entire sun can go out and we'll continue to see it shining brightly； we won't learn of its death； it may be； for ages to e—in fact； for how long it takes light； which travels fast but not infinitely fast； to cross the intervening vastness。
The immense distances to the stars and the galaxies mean that we see everything in space in the past—some as they were before the Earth came to be。 Telescopes are time machines。 Long ago； when an early galaxy began to pour light out into the surrounding darkness； no witness could have known that billions of years later some remote clumps of rock and metal； ice and organic molecules would fall together to make a place called Earth； or that life would arise and thinking beings evolve who would one day capture a little of that galactic light； and try to puzzle out what had sent it on its way。
And after the Earth dies； some 5 billion years from now； after it is burned to a crisp or even swallowed by the Sun； there will be other worlds and stars and galaxies ing into being—and they will know nothing of a place once called Earth。
IT ALMOST NEVER FEELS like prejudice。 Instead； it seems fitting and just—the idea that； because of an accident of birth； our group （whichever one it is） should have a central position in the social universe。 Among Pharaonic princelings and Plantagenet pretenders； children of robber barons and Central mittee bureaucrats； street gangs and conquerors of nations； members of confident majorities； obscure sects； and reviled minorities； this self…serving attitude seems as natural as breathing。 It draws sustenance from the same psychic wellsprings as sexism； racism； nationalism； and the other deadly chauvinisms that plague our species。 Unmon strength of character is needed to resist the blandishments of those who assure us that we have an obvious； even God…given； superiority over our fellows。 The more precarious our self…esteem； the greater our vulnerability to such appeals。
Since scientists are people； it is not surprising that parable pretensions have insinuated themselves into the scientific worldview。 Indeed； many of the central debates in the history of science seem to be； in part at least； contests over whether humans are special。 Almost always； the going…in assumption is that we are special。 After the premise is closely examined； though； it turns out—in dishearteningly many cases—that we are not。
Our ancestors lived out of doors。 They were as familiar with the night sky as most of us are with our favorite television programs。 The Sun； the Moon； the stars； and the planets all rose in the east and set in the west； traversing the sky overhead in the interim。 The motion of the heavenly bodies was not merely a diversion； eliciting a reverential nod and grunt； it was the only way to tell the time of day and the seasons。 For hunters and gatherers； as well as for agricultural peoples； knowing about the sky was a matter of life and death。
How lucky for us that the Sun； the Moon； the planets； and the stars are part of some elegantly configured cosmic clockwork！ It seemed to be no accident。 They were put here for a purpose； for our benefit。 Who else makes use of them？ What else are they good for？
And if the lights in the sky rise and set around us； isn't it evident that we're at the center of the Universe？ These celestial bodies—so clearly suffused with unearthly powers； especially the Sun on which we depend for light and heat—circle us like courtiers fawning on a king。 Even if we had not already guessed； the most elementary examination of the heavens reveals that we are special。 The Universe seems designed for human beings。 It's difficult to contemplate these circumstances without experiencing stirrings of pride and reassurance。 The entire Universe； made for us！ We must really be something。
This satisfying demonstration of our importance； buttressed by da