The surface of the Earth is the shore of the cosmic ocean. On this shore we have learned most of what we know. Recently, we’ve waded a little way out—maybe ankle-deep—and the water seems inviting. Some part of our being knows this is where we came from. We long to return. And we can. Because the cosmos is also within us. We’re made of star-stuff. We are a way for the cosmos to know itself.

The Shores of the Cosmic Ocean (1980)

Portrait of Carl Sagan

Carl Sagan

November 9, 1934 – December 20, 1996

Carl Edward Sagan was an American astronomer, cosmologist, astrophysicist, astrobiologist, author, science popularizer, and science communicator in astronomy and other natural sciences. He is best known for his work as a science popularizer and communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. Sagan argued the now accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect.

Sagan advocated scientific skeptical inquiry and the scientific method, pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI). He spent most of his career as a professor of astronomy at Cornell University, where he directed the Laboratory for Planetary Studies. Sagan and his works received numerous awards and honors, including the NASA Distinguished Public Service Medal, the National Academy of Sciences Public Welfare Medal, the Pulitzer Prize for General Non-Fiction for his book The Dragons of Eden, and, regarding Cosmos: A Personal Voyage, two Emmy Awards, the Peabody Award and the Hugo Award.


18 Documents






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Cover image for Cosmos 01: The Shores of the Cosmic Ocean

The Shores of the Cosmic Ocean

Cosmos, Episode 1

Carl Sagan opens the program with a description of the cosmos and a “spaceship of the imagination” shaped like a dandelion seed. The ship journeys through the universe’s hundred billion galaxies, the Local Group, the Andromeda galaxy, the Milky Way, the Orion Nebula, our solar system, and finally the planet Earth. Eratosthenes’ successful calculation of the circumference of Earth leads to a description of the ancient Library of Alexandria. Finally, the “Ages of Science” are described, before pulling back to the full span of the cosmic calendar.

Cover image for Cosmos 02: One Voice in the Cosmic Fugue

One Voice in the Cosmic Fugue

Cosmos, Episode 2

Sagan discusses the story of the Heike crab and artificial selection of crabs resembling samurai warriors, as an opening into a larger discussion of evolution through natural selection (and the pitfalls of intelligent design). Among the topics are the development of life on the Cosmic Calendar and the Cambrian explosion; the function of DNA in growth; genetic replication, repairs, and mutation; the common biochemistry of terrestrial organisms; the creation of the molecules of life in the Miller-Urey experiment; and speculation on alien life (such as life in Jupiter’s clouds). In the Cosmos Update ten years later, Sagan remarks on RNA also controlling chemical reactions and reproducing itself and the different roles of comets (potentially carrying organic molecules or causing the Cretaceous–Paleogene extinction event).

Cover image for Cosmos 03: Harmony of the Worlds

Harmony of the Worlds

Cosmos, Episode 3

Beginning with the separation of the fuzzy thinking and pious fraud of astrology from the careful observations of astronomy, Sagan follows the development of astronomical observation. Beginning with constellations and ceremonial calendars (such as those of the Anasazi), the story moves to the debate between Earth and Sun-centered models: Ptolemy and the geocentric worldview, Copernicus’ theory, the data-gathering of Tycho Brahe, and the achievements of Johannes Kepler (Kepler’s laws of planetary motion and the first science-fiction novel).

Cover image for Cosmos 04: Heaven and Hell

Heaven and Hell

Cosmos, Episode 4

Sagan discusses comets and asteroids as planetary impactors, giving recent examples of the Tunguska event and a lunar impact described by Canterbury monks in 1178. It moves to a description of the environment of Venus, from the previous fantastic theories of people such as Immanuel Velikovsky to the information gained by the Venera landers and its implications for Earth’s greenhouse effect. The Cosmos Update highlights the connection to global warming.

Cover image for Cosmos 05: Blues for a Red Planet

Blues for a Red Planet

Cosmos, Episode 5

The episode, devoted to the planet Mars, begins with scientific and fictional speculation about the Red Planet during the late nineteenth and early twentieth centuries (H. G. Wells’ The War of the Worlds, Edgar Rice Burroughs’ science fiction books, and Percival Lowell’s false vision of canals on Mars). It then moves to Robert Goddard’s early experiments in rocket-building, inspired by reading science fiction, and the work by Mars probes, including the Viking, searching for life on Mars. The episode ends with the possibility of the terraforming and colonization of Mars and a Cosmos Update on the relevance of Mars’ environment to Earth’s and the possibility of a manned mission to Mars.

Cover image for Cosmos 06: Travellers' Tales

Travellers' Tales

Cosmos, Episode 6

The journeys of the Voyager probes is put in the context of the Netherlands in the seventeenth century, with a centuries-long tradition of sailing ship explorers, and its contemporary thinkers (such as Constantijn Huygens and his son Christian). Their discoveries are compared to the Voyager probes’ discoveries among the Jovian and Saturn systems. In Cosmos Update, image processing reconstructs Voyager’s worlds and Voyager’s last portrait of the Solar System as it leaves is shown.

Cover image for Cosmos 07: The Backbone of Night

The Backbone of Night

Cosmos, Episode 7

Carl Sagan teaches students in a classroom in his childhood home in Brooklyn, New York, which leads into a history of the different mythologies about stars and the gradual revelation of their true nature. In ancient Greece, some philosophers (Aristarchus of Samos, Thales of Miletus, Anaximander, Theodorus of Samos, Empedocles, Democritus) freely pursue scientific knowledge, while others (Plato, Aristotle, and the Pythagoreans) advocate slavery and epistemic secrecy.

Cover image for Cosmos 08: Journeys in Space and Time

Journeys in Space and Time

Cosmos, Episode 8

Ideas about time and space are explored in the changes that constellations undergo over time, the redshift and blue shift measured in interstellar objects, time dilation in Albert Einstein’s theory of relativity, the designs of both Leonardo da Vinci and spacecraft that could travel near light speed, time travel and its hypothetical effects on human history, the origins of the Solar System, the history of life, and the immensity of space. In Cosmos Update, the idea of faster-than-light travel by wormholes (researched by Kip Thorne and shown in Sagan’s novel Contact) is discussed.

Cover image for Cosmos 09: The Lives of the Stars

The Lives of the Stars

Cosmos, Episode 9

The simple act of making an apple pie is extrapolated into the atoms and subatomic particles (electrons, protons, and neutrons) necessary. Many of the ingredients necessary are formed of chemical elements formed in the life and deaths of stars (such as our own Sun), resulting in massive red giants and supernovae or collapsing into white dwarfs, neutron stars, pulsars, and even black holes. These produce all sorts of phenomena, such as radioactivity, cosmic rays, and even the curving of spacetime by gravity. Cosmos Update mentions the supernova SN 1987A and neutrino astronomy.

Cover image for Cosmos 10: The Edge of Forever

The Edge of Forever

Cosmos, Episode 10

Beginning with the origins of the universe in the Big Bang, Sagan describes the formation of different types of galaxies and anomalies such as galactic collisions and quasars. The episode moves further into ideas about the structure of the Universe, such as different dimensions (in the imaginary Flatland and four-dimensional hypercubes), an infinite vs. a finite universe, and the idea of an oscillating Universe (similar to that in Hindu cosmology). The search into other ideas such as dark matter and the multiverse is shown, using tools such as the Very Large Array in New Mexico. Cosmos Update shows new information about the odd, irregular surfaces of galaxies and the Milky Way perhaps being a barred spiral galaxy.

Cover image for Cosmos 11: The Persistence of Memory

The Persistence of Memory

Cosmos, Episode 11

The idea of intelligence is explored in the concepts of computers (using bits as their basic units of information), whales (in their songs and their disruptions by human activities), DNA, the human brain (the evolution of the brain stem, frontal lobes, neurons, cerebral hemispheres, and corpus callosum under the Triune Brain Model), and man-made structures for collective intelligence (cities, libraries, books, computers, and satellites). The episode ends with speculation on alien intelligence and the information conveyed on the Voyager Golden Record.

Cover image for Cosmos 12: Encyclopædia Galactica

Encyclopædia Galactica

Cosmos, Episode 12

Questions are raised about the search for intelligent life beyond the Earth, with UFOs and other close encounters refuted in favor of communications through SETI and radio telescope such as the Arecibo Observatory. The probability of technically advanced civilizations existing elsewhere in the Milky Way is interpreted using the Drake equation and a future hypothetical Encyclopedia Galactica is discussed as a repository of information about other worlds in the galaxy. The Cosmos Update notes that there have been fewer sightings of UFOs and more stories of abductions, while mentioning the META scanning the skies for signals.

Cover image for Cosmos 13: Who Speaks for Earth?

Who Speaks for Earth?

Cosmos, Episode 13

Sagan reflects on the future of humanity and the question of "who speaks for Earth?" when meeting extraterrestrials. He discusses the very different meetings of the Tlingit people and explorer Jean-Francois de La Perouse with the destruction of the Aztecs by Spanish conquistadors, the looming threat of nuclear warfare, and the threats shown by destruction of the Library of Alexandria and the murder of Hypatia. The episode ends with an overview of the beginning of the universe, the evolution of life, and the accomplishments of humanity and makes a plea to mankind to cherish life and continue its journey in the cosmos. The Cosmos Update notes the preliminary reconnaissance of planets with spacecraft, the fall of the Berlin Wall and the end of apartheid in South Africa, and measures towards the reduction of nuclear weapons.

Mr. X

Written under the pseudonym Mr. X to avoid the heavy social stigma associated with marijuana consumption at the time, Carl Sagan documented his personal experiences with cannabis in this essay in order to dispel common misconceptions about the drug. It was later published in the 1971 book Marihuana Reconsidered by Lester Grinspoon. Sagan enjoyed cannabis on a regular basis for the rest of his life, but never spoke of it publicly.

Cover image for Pale Blue Dot

Pale Blue Dot

Cover image for Pale Blue Dot: A Vision of the Human Future in Space

Pale Blue Dot

A Vision of the Human Future in Space

Pulitzer Prize-winning author Carl Sagan traces our exploration of space and suggests that our very survival may depend on the wise use of other worlds. This stirring book reveals how scientific discovery has altered our perception of who we are and where we stand, and challenges us to weigh what we will do with that knowledge.

Studio 2 Interview

Carl Sagan as he unveils the profound insignificance of Earth within the vast expanse of the universe. He challenges our anthropocentric biases, urging us to embrace a more humble perspective. Sagan emphasizes the interconnectedness of life, highlighting the shared ancestry between humans and other species. He advocates for space exploration as a means of safeguarding humanity’s future while emphasizing the importance of scientific literacy for navigating the challenges of our time.

Cover image for The Varieties of Scientific Experience

The Varieties of Scientific Experience

Carl Sagan’s prescient exploration of the relationship between religion and science, and his personal search for God.

Mentioned in 10 documents

Gregory Stock


In this visionary book, Gregory Stock gives us a new way of understanding our world and our future. He develops the provocative thesis that human society has become an immense living being: a global superorganism in which we humans, knitted together by our modern technology and communication, are like the cells in an animal's body. Drawing on impressive research, Stock shows this newly formed superorganism to be more than metaphor: it is an actual living creature, which he has named Metaman, meaning beyond and transcending humans.

Marvin Minsky and Jeffrey Mishlove

Mind As Society

Conscious intelligence may be viewed as a computer system composed of many smaller parallel processing programs. Marvin Minsky, Ph.D., is one of the acknowledged founders of the mathematical theory of computation, artificial intelligence, and robotics. He argues that understanding the individual as a very sophisticated machine actually affirms human dignity.

Terence McKenna

Our Cyberspiritual Future

Terence holds court on our civilization's journey toward the eschaton at this weekend Esalen gathering. He riffs on topics from psychedelic states and alien intelligences to time travel and VR. McKenna argues we're evolving toward an unimaginable state of accelerating novelty, propelled by advancing technology. A mind-expanding ride for the open-minded psychonaut or armchair traveler, guided by one of the twentieth century's most eclectic thinkers.

Tim Urban

Religion for the Nonreligious

Kevin Kelly

Technium Unbound

What comes after the Internet? What is bigger than the web? What will produce more wealth than all the startups to date? The answer is a planetary superorganism comprised of 4 billion mobile phones, 80 quintillion transistor chips, a million miles of fiber optic cables, and 6 billion human minds all wired together. The whole thing acts like a single organism, with its own behavior and character—but at a scale we have little experience with. This is more than just a metaphor. Kevin Kelly takes the idea of a global superorganism seriously by describing what we know about it so far, how it is growing, where its boundaries are, and what it will mean for us as individuals and collectively.

Terence McKenna

The Edge Runner

A presentation revolving around the question: what is going on in the universe? Special emphasis is given to the human condition, the accelerating complexification of the cosmos, and options for the human collectivity as it faces the future.

David Yaden

The Overview Effect

Viewing the Earth from space has often prompted astronauts to report overwhelming emotion and feelings of identification with humankind and the planet as a whole. In this article, we explore this experience, known as the “overview effect.” We examine astronaut accounts of the overview effect and suggest existing psychological constructs, such as awe and self-transcendent experience, that might contribute to a psychological understanding of this experience. We argue that the overview effect suggests directions for future research on altered states of consciousness in new contexts, with potential implications for better understanding well-being in isolated, confined, extreme (ICE) environments such as space flight.

Terence McKenna

The Rites of Spring

Terence McKenna theorizes that ingestion of psilocybin mushrooms catalyzed the emergence of human self-reflection. He argues that psilocybin enhanced visual acuity and symbol processing in early hominids, leading to the development of human consciousness. Psychedelic plants can accelerate cultural change by deconditioning rigid mindsets, according to McKenna. He envisions a future where machines have consciousness and visible language communicates meaning directly. Ultimately, McKenna foresees the impending transformation of humanity through imagination and connection with the mysterious Other.

Erich Jantsch

The Self-Organizing Universe

The evolution of the universe—ranging from cosmic and biological to sociocultural evolution—is viewed in terms of the unifying paradigm of self-organization. The contours of this paradigm emerge from the synthesis of a number of important concepts, and provide a scientific foundation to a new world-view which emphasizes process over structure, nonequilibrium over equilibrium, evolution over permanency, and individual creativity over collective stabilization. The book, with its emphasis on the interaction of microstructures with the entire biosphere, ecosystems etc., and on how micro- and macrocosmos mutually create the conditions for their further evolution, provides a comprehensive framework for a deeper understanding of human creativity in a time of transition.

Kevin Kelly

What Technology Wants

One of today's most respected thinkers turns the conversation about technology on its head by viewing technology as a natural system, an extension of biological evolution. By mapping the behavior of life, we paradoxically get a glimpse at where technology is headed—or "what it wants." Kevin Kelly offers a dozen trajectories in the coming decades for this near-living system. And as we align ourselves with technology's agenda, we can capture its colossal potential. This visionary and optimistic book explores how technology gives our lives greater meaning and is a must-read for anyone curious about the future.