In 1980, the most iconic writer in scientific communication and a brilliant scientist, Carl Sagan, while being a professor at Cornell University, decided to have a 2-year sabbatical in order to launch a great project: to summarize the scientific knowledge obtained by humanity until his time and give it generously to the people! This mission was more than accomplished, in an almost epic way, leaving as legacy two great works with the same title, a book and a tv-series. In this article we’re going to discuss only the book, in another, soon, we’ll present the tv-series and its remakes.
The idea for “Cosmos” was to create a series which could describe the voyage of our species and its achievements in science and culture, in past, present but also in the future, by presenting questions on it. Sagan was in charge to direct and present the work and the first thing he did was to write a marvelous book, which was included by the US Congress among the “88 books who shaped America”.
The 13 chapters of the book are the content of the 13 episodes of the series, filmed during the same period. Though, the expression form gave the opportunity to the writer to develop his ideas and thoughts much more deeply that anyone can achieve in an almost 1 hour of a tv episode. In its 367 pages, he unfolds a history of knowledge, taking us in a voyage into the greatest and some of the darkest stories of the adventure of humanity, in its endeavor to understand the world and to live in the only planet we know that life exists, so far, the Earth.
Let’s have an inside look, quoting some stupendous excerpts…
Chapter 1 – The Shores of the Cosmic Ocean
In this introduction, the writer aims to put the reader in the position of an observer of the universe. In order to describe the way we understand spatial and temporal dimensions in common life, in relation to those of universe, he introduces the notion of the “cosmic calendar”, where 13.5 (15 as known then) billion years of the age of universe are compressed in an analogy with a yearly calendar, into which the duration of human history corresponds to the last seconds of its last night.
In the mean time, he makes a voyage in time, to the first moments when human understood its place into the space of universe, referring Eratosthenes’s experiments, the knowledge produced at Alexandria’s Library and the contribution of those first scientists to the pursuit of knowledge by the methodology we use today in natural sciences, even if humanity buried it for almost 20 centuries.
“Some stars may be surrounded by millions of lifeless and rocky worldlets, planetary systems frozen at some early stage in their evolution. Perhaps many stars have planetary systems rather like our own: at the periphery, great gaseous ringed planets and icy moons, and nearer to the center, small, warm, blue-white, cloud-covered worlds. On some, intelligent life may have evolved, reworking the planetary surface in some massive engineering enterprise. These are our brothers and sisters in the Cosmos. Are they very different from us? What is their form, biochemistry, neurobiology, history, politics, science, technology, art, music, religion, philosophy? Perhaps some day we will know them.”
“One of his envious contemporaries called him ‘Beta,’ the second letter of the Greek alphabet, because, he said, Eratosthenes was second best in the world in everything. But it seems clear that in almost everything Eratosthenes was ‘Alpha.’ He was an astronomer, historian, geographer, philosopher, poet, theater critic and mathematician.”
Chapter 2 – One Voice in the Cosmic Fugue
In the second chapter, Sagan attempts to approach the fundamental ideas for the evolution of life on Earth, with an explanation of the concepts of natural and artificial selection, concerning the species’ evolution. Based on our knowledge for life in our planet, he asks important questions on how it could be in other worlds, completely unknown to us. He represents the ensemble of our knowledge for life as a music theme, in a huge cosmic fugue, as he wants to show how many different themes should exist in a cosmos much bigger than what we can understand with our senses and our experience in our planet.
“All life on Earth is closely related. We have a common organic chemistry and a common evolutionary heritage. As a result, our biologists are profoundly limited. They study only a single kind of biology, one lonely theme in the music of life. Is this faint and reedy tune the only voice for thousands of light-years? Or is there a kind of cosmic fugue, with themes and counterpoints, dissonances and harmonies, a billion different voices playing the life music of the Galaxy?”
Chapter 3 – The Harmony of Worlds
In the third chapter, Sagan starts the voyage into the endeavors of the first scientists who tried to put universe in an order. He explains the first approach, under the sight of a powerful creator, who imposed a harmony to its creation, up to the progressive collapse of this concept by the elements brought by those who dared to pass the Rubicon and change the old “perfect universe”. The work of Kepler, Tycho Brahe, Newton and the contribution of Copernicus and Galileo are presented, in order to understand the meaning of the passage from the concept of “God’s Universe” to “Nature’s Universe”, whose laws we are invited to reveal in a different way, as they’re not a product of the thought of a supernatural being.
“We today can recognize the antiquity of astrology in words such as disaster, which is Greek for ‘bad star,’ influenza, Italian for (astral) ‘influence’; mazeltov, Hebrew – and, ultimately, Babylonian – for ‘good constellation,’ or the Yiddish word shlamazel, applied to someone plagued by relentless ill-fortune, which again traces to the Babylonian astronomical lexicon. According to Pliny, there were Romans considered sideratio, ‘planetstruck.’ Planets were widely thought to be a direct cause of death. Or consider consider: it means ‘with the planets,’ evidently the prerequisite for serious reflection.”
Chapter 4 – Heaven and Hell
The first voyage to another world starts with Venus, the planet who seemed to be Heaven and turned to be Hell, quoting from Kazantzakis in its introduction: ““The doors of heaven and hell are adjacent and identical”. From there he starts the story telling of the discoveries of the first worlds, which are in fact the planets of our Solar System. Finally, he introduces for the first time the comparison of the evolution of our planet with this of the neighboring ones, revealing questions to be answered, on the conditions who lead to our existence on ours.
“The asteroid belt may be a place where a planet was once prevented from forming because of the gravitational tides of the giant nearby planet Jupiter; or it may be the shattered remains of a planet that blew itself up. This seems improbable because no scientist on Earth knows how a planet might blow itself up, which is probably just as well.”
Chapter 5 – Blues for a Red Planet
The second world presented is Mars, the planet who seems to day the most logical choice to move. There is an extensive reference to all the right and wrong estimations for the conditions on it, as well as how any doubts (or certainties) on them started to be validated with space missions. It’s analyzed in a greater level the approach of humanity used to discover, or not, the past or present life on the red planet, not any more with the observation from our home, but with our presence on its soil, through the technology that we have developed.
“Many years ago, so the story goes, a celebrated newspaper publisher sent a telegram to a noted astronomer: WIRE COLLECT IMMEDIATELY FIVE HUNDRED WORDS ON WHETHER THERE IS LIFE ON MARS. The astronomer dutifully replied: NOBODY KNOWS, NOBODY KNOWS, NOBODY KNOWS . . . 250 times”
Chapter 6 – Travelers’ Tales
Maybe one of the most exciting chapters. In it, Sagan presents humanity’s voyage into the vast cosmic ocean, outside the borders of our Solar System, with the Voyager and Pioneer pairs of spacecrafts. He compares the discovery of our own planet, some centuries ago, with today’s discovery of a much bigger space, into the great depths of this ocean, unobservable some years ago, by us, who standing in a shore, could only see the foam of the sea.
Cristian Huygens: “The world is my country,’ he said, ‘science my religion.”
“That place, called the heliopause, is one definition of the outer boundary of the Empire of the Sun. But the Voyager spacecraft will plunge on, penetrating the heliopause sometime in the middle of the twenty-first century, skimming through the ocean of space, never to enter another solar system, destined to wander through eternity far from the stellar islands and to complete its first circumnavigation of the massive center of the Milky Way a few hundred million years from now. We have embarked on epic voyages.”
Chapter 7 – The Backbone of Night
In this point Sagan attempts and abstraction, trying to create a timeline of sky’s understanding by humans, from the formation of the first small groups of our species up to our modern social formation. He emphasizes on the contribution of Greek philosophers, acclaiming the work of materialist Ionian philosophers and showing that the way it was conceived and destroyed by other philosophers, confortable in their small and indifferent universe of their time, as well as in their societies, lead to the scientific delay of humanity for thousand of years.
“In love with whole numbers, the Pythagoreans believed all things could be derived from them, certainly all other numbers. A crisis in doctrine arose when they discovered that the square root of two (the ratio of the diagonal to the side of a square) was irrational, that it cannot be expressed accurately as the ratio of any two whole numbers, no matter how big these numbers are. Ironically this discovery (reproduced in Appendix 1) was made with the Pythagorean theorem as a tool. ‘Irrational’ originally meant only that a number could not be expressed as a ratio. But for the Pythagoreans it came to mean something threatening, a hint that their world view might not make sense, which is today the other meaning of ‘irrational.’”
“Plato and Aristotle were comfortable in a slave society. They offered justifications for oppression. They served tyrants. They taught the alienation of the body from the mind (a natural enough ideal in a slave society); they separated matter from thought; they divorced the Earth from the heavens – divisions that were to dominate Western thinking for more than twenty centuries. Plato, who believed that ‘all things are full of gods,’ actually used the metaphor of slavery to connect his politics with his cosmology. He is said to have urged the burning of all the books of Democritus (he had a similar recommendation for the books of Homer), perhaps because Democritus did not acknowledge immortal souls or immortal gods or Pythagorean mysticism, or because he believed in an infinite number of worlds. Of the seventy-three books Democritus is said to have written, covering all of human knowledge, not a single work survives. All we know is from fragments, chiefly on ethics, and secondhand accounts. The same is true of almost all the other ancient Ionian scientists.”
Chapter 8 – Travels in Space and Time
Continuing to elaborate these thoughts, he puts the future timeline of discoveries, writing about interstellar travels, which defy the empirical concept of space and time as we understand them imprisoned on Earth. He clearly questions our ability to move in a space much bigger than this of our planet, in order to save ourselves and survive and he claims that all the delays, represented in the previous chapter, due to stuck into solid ideas of the past, are only obstacles in our effort to achieve this goal, putting in danger even the survival of our species.
“Europeans around the turn of the century generally believed in privileged frames of reference: that German, or French, or British culture and political organization were better than those of other countries; that Europeans were superior to other peoples who were fortunate enough to be colonized. The social and political application of the ideas of Aristarchus and Copernicus was rejected or ignored. The young Einstein rebelled against the notion of privileged frames of reference in physics as much as he did in politics. In a universe filled with stars rushing helter-skelter in all directions, there was no place that was ‘at rest,’ no framework from which to view the universe that was superior to any other framework. This is what the word relativity means.”
“It is a lovely fantasy, to explore those worlds that never were. By visiting them we could truly understand how history works; history could become an experimental science. If an apparently pivotal person had never lived – Plato, say, or Paul, or Peter the Great – how different would the world be? What if the scientific tradition of the ancient Ionian Greeks had survived and flourished? That would have required many of the social forces of the time to have been different – including the prevailing belief that slavery was natural and right. But what if that light that dawned in the eastern Mediterranean 2,500 years ago had not flickered out? What if science and the experimental method and the dignity of crafts and mechanical arts had been vigorously pursued 2,000 years before the Industrial Revolution? What if the power of this new mode of thought had been more generally appreciated? I sometimes think we might then have saved ten or twenty centuries. Perhaps the contributions of Leonardo would have been made a thousand years ago and those of Albert Einstein five hundred years ago. In such an alternate Earth, Leonardo and Einstein would, of course, never have been born. Too many things would have been different. In every ejaculation there are hundreds of millions of sperm cells, only one of which can fertilize an egg and produce a member of the next generation of human beings. But which sperm succeeds in fertilizing an egg must depend on the most minor and insignificant of factors, both internal and external. If even a little thing had gone differently 2,500 years ago, none of us would be here today. There would be billions of others living in our place.
If the Ionian spirit had won, I think we – a different ‘we,’ of course – might by now be venturing to the stars. Our first survey ships to Alpha Centauri and Barnard’s Star, Sirius and Tau Ceti would have returned long ago. Great fleets of interstellar transports would be under construction in Earth orbit – unmanned survey ships, liners for immigrants, immense trading ships to plow the seas of space. On all these ships there would be symbols and writing. If we looked closely, we might see that the language was Greek. And perhaps the symbol on the bow of one of the first starships would be a dodecahedron, with the inscription ‘Starship Theodorus of the Planet Earth.’”
“In all those other worlds in space there are events in progress, occurrences that will determine their futures. And on our small planet, this moment in history is a historical branch point as profound as the confrontation of the Ionian scientists with the mystics 2,500 years ago. What we do with our world in this time will propagate down through the centuries and powerfully determine the destiny of our descendants and their fate, if any, among the stars.”
Chapter 9 – The Lives of the Stars
At this point, Sagan starts to talk about stars’ chemistry, composition and the material from which all the universe is made. He explains that the reasons of stars’ birth, as the evolutionary process which is giving birth to them and makes them die, is exactly the same who lead to the birth of life, made by the same elements, from the most common atoms into all space and time we can observe and study today.
“All the elements of the Earth except hydrogen and some helium have been cooked by a kind of stellar alchemy billions of years ago in stars, some of which are today inconspicuous white dwarfs on the other side of the Milky Way Galaxy. 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.”
“The origin and evolution of life are connected in the most intimate way with the origin and evolution of the stars. First: The very matter of which we are composed, the atoms that make life possible, were generated long ago and far away in giant red stars. The relative abundance of the chemical elements found in the Cosmos matches the relative abundance of atoms generated in stars so well as to leave little doubt that red giants and supernovae are the ovens and crucibles in which matter has been forged. The Sun is a second- or third-generation star. All the matter in it, all the matter you see around you, has been through one or two previous cycles of stellar alchemy. Second: The existence of certain varieties of heavy atoms on the Earth suggests that there was a nearby supernova explosion shortly before the solar system was formed. But this is unlikely to be a mere coincidence; more likely, the shock wave produced by the supernova compressed interstellar gas and dust and triggered the condensation of the solar system. Third: When the Sun turned on, its ultraviolet radiation poured into the atmosphere of the Earth; its warmth generated lightning; and these energy sources sparked the complex organic molecules that led to the origin of life. Fourth: Life on Earth runs almost exclusively on sunlight. Plants gather the photons and convert solar to chemical energy. Animals parasitize the plants. Farming is simply the methodical harvesting of sunlight, using plants as grudging intermediaries. We are, almost all of us, solar-powered. Finally, the hereditary changes called mutations provide the raw material for evolution. Mutations, from which nature selects its new inventory of life forms, are produced in part by cosmic rays – high-energy particles ejected almost at the speed of light in supernova explosions. The evolution of life on Earth is driven in part by the spectacular deaths of distant, massive suns.”
Chapter 10 – The Edge of Forever
In the tenth chapter, Sagan introduces us to many concepts for the universe, which seem to be difficult to understand in common life, with most important the notions for space and time on it, in a universal scale. Explaining with simple words and examples concepts of modern physics, he achieves to create a global picture on how universe moves and specially on hoy we can understand at any moment our place in it, as observers at the interior of a system.
“In that titanic cosmic explosion, the universe began an expansion which has never ceased. It is misleading to describe the expansion of the universe as a sort of distending bubble viewed from the outside. By definition, nothing we can ever know about was outside. It is better to think of it from the inside, perhaps with grid lines imagined to adhere to the moving fabric of space expanding uniformly in all directions.”
“In considering the quasars, we confront profound mysteries. Whatever the cause of a quasar explosion, one thing seems clear: such a violent event must produce untold havoc. In every quasar explosion millions of worlds – some with life and the intelligence to understand what is happening – may be utterly destroyed. The study of the galaxies reveals a universal order and beauty. It also shows us chaotic violence on a scale hitherto undreamed of. That we live in a universe which permits life is remarkable. That we live in one which destroys galaxies and stars and worlds is also remarkable. The universe seems neither benign nor hostile, merely indifferent to the concerns of such puny creatures as we.”
“In many cultures it is customary to answer that God created the universe out of nothing. But this is mere temporizing. If we wish courageously to pursue the question, we must, of course ask next where God comes from. And if we decide this to be unanswerable, why not save a step and decide that the origin of the universe is an unanswerable question? Or, if we say that God has always existed, why not save a step and conclude that the universe has always existed?”
“We can imagine generating a cube in the following way: Take a line segment of a certain length and move it an equal length at right angles to itself. That makes a square. Move the square an equal length at right angles to itself, and we have a cube. We understand this cube to cast a shadow, which we usually draw as two squares with their vertices connected. If we examine the shadow of a cube in two dimensions, we notice that not all the lines appear equal, and not all the angles are right angles. The three-dimensional object has not been perfectly represented in its transfiguration into two dimensions. This is the cost of losing a dimension in the geometrical projection. Now let us take our three-dimensional cube and carry it, at right angles to itself, through a fourth physical dimension: not left-right, not forward-back, not up-down, but simultaneously at right angles to all those directions. I cannot show you what direction that is, but I can imagine it to exist. In such a case, we would have generated a four-dimensional hypercube, also called a tesseract. I cannot show you a tesseract, because we are trapped in three dimensions. But what I can show you is the shadow in three dimensions of a tesseract. It resembles two nested cubes, all the vertices connected by lines. But for a real tesseract, in four dimensions, all the lines would be of equal length and all the angles would be right angles.”
Chapter 11 – The Persistence of Memory
Posing some first questions on the way that our species exists, explaining the concept of consciousness, decision making, personal or collective, Sagan starts to approach the great question of a contact between humanity and civilizations very different from the only one we already know, the terrestrial, the human as the most intelligent on our planet. He asks questions concerning the use of technology, which actually should be answered in a future era of humanity, who either will achieve to survive with it, or will never achieve to bypass the point when a civilization survives having the means for its self destruction.
“We humans, as a species, are interested in communication with extraterrestrial intelligence. Would not a good beginning be improved communication with terrestrial intelligence, with other human beings of different cultures and languages, with the great apes, with the dolphins, but particularly with those intelligent masters of the deep, the, great whales?”
“And finally, on the outside, living in uneasy truce with the more primitive brains beneath, is the cerebral cortex, which evolved millions of years ago in our primate ancestors. The cerebral cortex, where matter is transformed into consciousness, is the point of embarkation for all our cosmic voyages. Comprising more than two-thirds of the brain mass, it is the realm of both intuition and critical analysis. It is here that we have ideas and inspirations, here that we read and write, here that we do mathematics and compose music. The cortex regulates our conscious lives. It is the distinction of our species, the seat of our humanity. Civilization is a product of the cerebral cortex.”
“Our intelligence has recently provided us with awesome powers. It is not yet clear that we have the wisdom to avoid our own self-destruction. But many of us are trying very hard. We hope that very soon in the perspective of cosmic time we will have unified our planet peacefully into an organization cherishing the life of every living creature on it and will be ready to take that next great step, to become part of a galactic society of communicating civilizations.”
Chapter 12 – Encyclopaedia Galactica
Just before the end, Sagan explains the possibilities to come in contact with another civilization, the parameters indicating how many of them can exist in a given space around us, analyzing Drake’s equation and finally how many of them who ever existed will continue to do so for as much time as we need (or they need) to meet each other.
“If civilizations tend to destroy themselves soon after reaching a technological phase, there might be no one for us to talk with but ourselves. And that we do but poorly. Civilizations would take billions of years of tortuous evolution to arise, and then snuff themselves out in an instant of unforgivable neglect.
But consider the alternative, the prospect that at least some civilizations learn to live with high technology; that the contradictions posed by the vagaries of past brain evolution are consciously resolved and do not lead to self-destruction; or that, even if major disturbances do occur, they are reversed in the subsequent billions of years of biological evolution. Such societies might live to a prosperous old age, their lifetimes measured perhaps on geological or stellar evolutionary time scales. If 1 percent of civilizations can survive technological adolescence, take the proper fork at this critical historical branch point and achieve maturity, then fL » 1/100, N » 107, and the number of extant civilizations in the Galaxy is in the millions. Thus, for all our concern about the possible unreliability of our estimates of the early factors in the Drake equation, which involved astronomy, organic chemistry and evolutionary biology, the principal uncertainty comes down to economics and politics and what, on Earth, we call human nature. It seems fairly clear that if self-destruction is not the overwhelmingly preponderant fate of galactic civilizations, then the sky is softly humming with messages from the stars.”
Chapter 13 – Who Speaks for Earth?
In the conclusion of his magnificent work, Sagan introduces the concept of the civilization of a whole planet, which doesn’t represent only humans and cannot be conceived as a big nation. By surpassing barriers that humanity used for centuries, he explain that through our perception of our place in universe, our reflections for the development of a communication and coexistence with all kinds of life we can find in it, it is absolutely necessary a completely different view on our history, of the evolution of our presence on our planet. He presents as the outcome of these thoughts that we are children of the universe, made by the matter which consists the Cosmos and we are obliged to survive, in order to understand it and thus to not destroy the amazing coincidence to exist sometime into its eternity.
“Alexandria was the greatest city the Western world had ever seen. People of all nations came there to live, to trade, to learn. On any given day, its harbors were thronged with merchants, scholars and tourists. This was a city where Greeks, Egyptians, Arabs, Syrians, Hebrews, Persians, Nubians, Phoenicians, Italians, Gauls and Iberians exchanged merchandise and ideas. It is probably here that the word cosmopolitan realized its true meaning – citizen, not just of a nation, but of the Cosmos.* To be a citizen of the Cosmos…”
“A few million years ago there were no humans. Who will be here a few million years hence? In all the 4.6-billion-year history of our planet, nothing much ever left it. But now, tiny unmanned exploratory spacecraft from Earth are moving, glistening and elegant, through the solar system. We have made a preliminary reconnaissance of twenty worlds, among them all the planets visible to the naked eye, all those wandering nocturnal lights that stirred our ancestors toward understanding and ecstasy. If we survive, our time will be famous for two reasons: that at this dangerous moment of technological adolescence we managed to avoid self-destruction; and because this is the epoch in which we began our journey to the stars.
The choice is stark and ironic. The same rocket boosters used to launch probes to the planets are poised to send nuclear warheads to the nations. The radioactive power sources on Viking and Voyager derive from the same technology that makes nuclear weapons. The radio and radar techniques employed to track and guide ballistic missiles and defend against attack are also used to monitor and command the spacecraft on the planets and to listen for signals from civilizations near other stars. If we use these technologies to destroy ourselves, we surely will venture no more to the planets and the stars. But the converse is also true. If we continue to the planets and the stars, our chauvinisms will be shaken further. We will gain a cosmic perspective. We will recognize that our explorations can be carried out only on behalf of all the people of the planet Earth. We will invest our energies in an enterprise devoted not to death but to life: the expansion of our understanding of the Earth and its inhabitants and the search for life elsewhere. Space exploration – unmanned and manned – uses many of the same technological and organizational skills and demands the same commitment to valor and daring as does the enterprise of war. Should a time of real disarmament arrive before nuclear war, such exploration would enable the military-industrial establishments of the major powers to engage at long last in an untainted enterprise. Interests vested in preparations for war can relatively easily be reinvested in the exploration of the Cosmos.”
“Some 3.6 million years ago, in what is now northern Tanzania, a volcano erupted, the resulting cloud of ash covering the surrounding savannahs. In 1979, the paleoanthropologist Mary Leakey found in that ash footprints – the footprints, she believes, of an early hominid, perhaps an ancestor of all the people on the Earth today. And 380,000 kilometers away, in a flat dry plain that humans have in a moment of optimism called the Sea of Tranquility, there is another footprint, left by the first human to walk another world. We have come far in 3.6 million years, and in 4.6 billion and in 15 billion.
For we are the local embodiment of a Cosmos grown to self-awareness. We have begun to contemplate our origins: starstuff pondering the stars; organized assemblages of ten billion billion billion atoms considering the evolution of atoms; tracing the long journey by which, here at least, consciousness arose. Our loyalties are to the species and the planet. We speak for Earth. Our obligation to survive is owed not just to ourselves but also to that Cosmos, ancient and vast, from which we spring.”