Authors: Carl Sagan
I would rather understand one cause than be King of Persia.
—Democritus of Abdera
If a faithful account was rendered of Man’s ideas upon Divinity, he would be obliged to acknowledge, that for the most part the word “gods” has been used to express the concealed, remote, unknown causes of the effects he witnessed; that he applies this term when the spring of the natural, the source of known causes, ceases to be visible: as soon as he loses the thread of these causes, or as soon as his mind can no longer follow the chain, he solves the difficulty, terminates his research, by ascribing it to his gods … When, therefore, he ascribes to his gods the production of some phenomenon … does he, in fact, do any thing more than substitute for the darkness of his own mind, a sound to which he has been accustomed to listen with reverential awe?
—Paul Heinrich Dietrich, Baron von Holbach,
Système de la Nature
, London, 1770
When I was little, I lived in the Bensonhurst section of Brooklyn in the City of New York. I knew my immediate neighborhood intimately, every apartment building, pigeon coop, backyard, front stoop, empty lot, elm tree, ornamental railing, coal chute and wall for playing Chinese handball, among which the brick exterior of a theater called the Loew’s Stillwell was of superior quality. I knew where many people lived: Bruno and Dino, Ronald and Harvey, Sandy, Bernie, Danny, Jackie and Myra. But more than a few blocks away, north of the raucous automobile traffic and elevated railway on 86th Street, was a strange unknown territory, off-limits to my wanderings. It could have been Mars for all I knew.
Even with an early bedtime, in winter you could sometimes see the stars. I would look at them, twinkling and remote, and
wonder what they were. I would ask older children and adults, who would only reply, “They’re lights in the sky, kid.” I could
see
they were lights in the sky. But what
were
they? Just small hovering lamps? Whatever for? I felt a kind of sorrow for them: a commonplace whose strangeness remained somehow hidden from my incurious fellows. There had to be some deeper answer.
As soon as I was old enough, my parents gave me my first library card. I think the library was on 85th Street, an alien land. Immediately, I asked the librarian for something on stars. She returned with a picture book displaying portraits of men and women with names like Clark Gable and Jean Harlow. I complained, and for some reason then obscure to me, she smiled and found another book—the right kind of book. I opened it breathlessly and read until I found it. The book said something astonishing, a very big thought. It said that the stars were suns, only very far away. The Sun was a star, but close up.
Imagine that you took the Sun and moved it so far away that it was just a tiny twinkling point of light. How far away would you have to move it? I was innocent of the notion of angular size. I was ignorant of the inverse square law for light propagation. I had not a ghost of a chance of calculating the distance to the stars. But I could tell that if the stars were suns, they had to be very far away—farther away than 85th Street, farther away than Manhattan, farther away, probably, than New Jersey. The Cosmos was much bigger than I had guessed.
Later I read another astonishing fact. The Earth, which includes Brooklyn, is a planet, and it goes around the Sun. There are other planets. They also go around the Sun; some are closer to it and some are farther away. But the planets do not shine by their own light, as the Sun does. They merely reflect light from the Sun. If you were a great distance away, you would not see the Earth and the other planets at all; they would be only faint luminous points, lost in the glare of the Sun. Well, then, I thought, it stood to reason that the other stars must have planets too, ones we have not yet detected, and some of those other planets should have life (why not?), a kind of life probably different from life as we know it, life in Brooklyn. So I decided I would be an astronomer, learn about the stars and planets and, if I could, go and visit them.
It has been my immense good fortune to have parents and some teachers who encouraged this odd ambition and to live in this time, the first moment in human history when we are, in fact, visiting other worlds and engaging in a deep reconnaissance of the Cosmos. If I had been born in a much earlier age, no matter how great my
dedication, I would not have understood what the stars and planets are. I would not have known that there were other suns and other worlds. This is one of the great secrets, wrested from Nature through a million years of patient observation and courageous thinking by our ancestors.
What are the stars? Such questions are as natural as an infant’s smile. We have always asked them. What is different about our time is that at last we know some of the answers. Books and libraries provide a ready means for finding out what those answers are. In biology there is a principle of powerful if imperfect applicability called recapitulation: in our individual embryonic development we retrace the evolutionary history of the species. There is, I think, a kind of recapitulation that occurs in our individual intellectual developments as well. We unconsciously retrace the thoughts of our remote ancestors. Imagine a time before science, a time before libraries. Imagine a time hundreds of thousands of years ago. We were then just about as smart, just as curious, just as involved in things social and sexual. But the experiments had not yet been done, the inventions had not yet been made. It was the childhood of genus
Homo
. Imagine the time when fire was first discovered. What were human lives like then? What did our ancestors believe the stars were? Sometimes, in my fantasies, I imagine there was someone who thought like this:
We eat berries and roots. Nuts and leaves. And dead animals. Some animals we find. Some we kill. We know which foods are good and which are dangerous. If we taste some foods we are struck down, in punishment for eating them. We did not mean to do something bad. But foxglove or hemlock can kill you. We love our children and our friends. We warn them of such foods
.
When we hunt animals, then also can we be killed. We can be gored. Or trampled. Or eaten. What animals do means life and death for us: how they behave, what tracks they leave, their times for mating and giving birth, their times for wandering. We must know these things. We tell our children. They will tell their children
.
We depend on animals. We follow them—especially in winter when there are few plants to eat. We are wandering hunters and gatherers. We call ourselves the hunterfolk
.
Most of us fall asleep under the sky or under a tree or in its branches. We use animal skins for clothing: to keep us warm, to cover our nakedness and sometimes as a hammock. When we wear the animal skins we feel the animal’s power. We leap with the gazelle. We hunt with the bear. There is a bond between us and
the animals. We hunt and eat the animals. They hunt and eat us. We are part of one another
.
We make tools and stay alive. Some of us are experts at splitting, flaking, sharpening and polishing, as well as finding, rocks. Some rocks we tie with animal sinew to a wooden handle and make an ax. With the ax we strike plants and animals. Other rocks are tied to long sticks. If we are quiet and watchful, we can sometimes come close to an animal and stick it with the spear
.
Meat spoils. Sometimes we are hungry and try not to notice. Sometimes we mix herbs with the bad meat to hide the taste. We fold foods that will not spoil into pieces of animal skin. Or big leaves. Or the shell of a large nut. It is wise to put food aside and carry it. If we eat this food too early, some of us will starve later. So we must help one another. For this and many other reasons we have rules. Everyone must obey the rules. We have always had rules. Rules are sacred
.
One day there was a storm, with much lightning and thunder and rain. The little ones are afraid of storms. And sometimes so am I. The secret of the storm is hidden. The thunder is deep and loud; the lightning is brief and bright. Maybe someone very powerful is very angry. It must be someone in the sky, I think
.
After the storm there was a flickering and crackling in the forest nearby. We went to see. There was a bright, hot, leaping thing, yellow and red. We had never seen such a thing before. We now call it “flame.” It has a special smell. In a way it is alive. It eats food. It eats plants and tree limbs and even whole trees, if you let it. It is strong. But it is not very smart. If all the food is gone, it dies. It will not walk a spear’s throw from one tree to another if there is no food along the way. It cannot walk without eating. But where there is much food, it grows and makes many flame children
.
One of us had a brave and fearful thought: to capture the flame, feed it a little, and make it our friend. We found some long branches of hard wood. The flame was eating them, but slowly. We could pick them up by the end that had no flame. If you run fast with a small flame, it dies. Their children are weak. We did not run. We walked, shouting good wishes. “Do not die,” we said to the flame. The other hunterfolk looked with wide eyes
.
Ever after, we have carried it with us. We have a flame mother to feed the flame slowly so it does not die of hunger
.
*
Flame is
a wonder, and useful too; surely a gift from powerful beings. Are they the same as the angry beings in the storm?
The flame keeps us warm on cold nights. It gives us light. It makes holes in the darkness when the Moon is new. We can fix spears at night for tomorrow’s hunt. And if we are not tired, even in the darkness we can see each other and talk. Also—a good thing!—fire keeps animals away. We can be hurt at night. Sometimes we have been eaten, even by small animals, hyenas and wolves. Now it is different. Now the flame keeps the animals back. We see them baying softly in the dark, prowling, their eyes glowing in the light of the flame. They are frightened of the flame. But we are not frightened. The flame is ours. We take care of the flame. The flame takes care of us
.
The sky is important. It covers us. It speaks to us. Before the time we found the flame, we would lie back in the dark and look up at all the points of light. Some points would come together to make a picture in the sky. One of us could see the pictures better than the rest. She taught us the star pictures and what names to call them. We would sit around late at night and make up stories about the pictures in the sky: lions, dogs, bears, hunterfolk. Other, stranger things. Could they be the pictures of the powerful beings in the sky, the ones who make the storms when angry?
Mostly, the sky does not change. The same star pictures are there year after year. The Moon grows from nothing to a thin sliver to a round ball, and then back again to nothing. When the Moon changes, the women bleed. Some tribes have rules against sex at certain times in the growing and shrinking of the Moon. Some tribes scratch the days of the Moon or the days that the women bleed on antler bones. Then they can plan ahead and obey their rules. Rules are sacred
.
The stars are very far away. When we climb a hill or a tree they are no closer. And clouds come between us and the stars: the stars must be behind the clouds. The Moon, as it slowly moves, passes in front of stars. Later you can see that the stars are not harmed. The Moon does not eat stars. The stars must be behind the Moon. They flicker. A strange, cold, white faraway light. Many of them. All over the sky. But only at night. I wonder what they are
.
After we found the flame, I was sitting near the campfire wondering about the stars. Slowly a thought came: The stars are flame, I thought. Then I had another thought: The stars are campfires that other hunterfolk light at night. The stars give a smaller light than campfires. So the stars must be campfires very far away. “But,” they ask me, “how can there be campfires in the sky? Why do the campfires and the hunter people around those flames not fall down at our feet? Why don’t strange tribes drop from the sky?”
Those are good questions. They trouble me. Sometimes I think the sky is half of a big eggshell or a big nutshell. I think the people around those faraway campfires look down at us—except for them it seems up—and say that we are in their sky, and wonder why we do not fall up to them, if you see what I mean. But hunterfolk say, “Down is down and up is up.” That is a good answer, too
.
There is another thought that one of us had. His thought is that night is a great black animal skin, thrown up over the sky. There are holes in the skin. We look through the holes. And we see flame. His thought is not just that there is flame in a few places where we see stars. He thinks there is flame everywhere. He thinks flame covers the whole sky. But the skin hides the flame. Except where there are holes
.
Some stars wander. Like the animals we hunt. Like us. If you watch with care over many months, you find they move. There are only five of them, like the fingers on a hand. They wander slowly among the stars. If the campfire thought is true, those stars must be tribes of wandering hunterfolk, carrying big fires. But I don’t see how wandering stars can be holes in a skin. When you make a hole, there it is. A hole is a hole. Holes do not wander. Also, I don’t want to be surrounded by a sky of flame. If the skin fell, the night sky would be bright—too bright—like seeing flame everywhere. I think a sky of flame would eat us all. Maybe there are two kinds of powerful beings in the sky. Bad ones, who wish the flame to eat us. And good ones who put up the skin to keep the flame away. We must find some way to thank the good ones
.
I don’t know if the stars are campfires in the sky. Or holes in a skin through which the flame of power looks down on us. Sometimes I think one way. Sometimes I think a different way. Once I thought there are no campfires and no holes but something else, too hard for me to understand
.