El Universo

Spacecraft missions to nearby Planets The Library of ancient Alexandria The human brain Egyptian Hieroglyphics The origin of life The death of the Sun The evolution of galaxies The origins of matter, suns and worlds COSMOS The story of fifteen billion years of cosmic evolution transforming matter and life into consciousness, of how science and civilization grew up together, and of the forces andindividuals who helped shape modern science. A story told with Carl Sagan’s remarkable ability to make scientific ideas both comprehensible and exciting, based on his acclaimed television series.

For Ann Druyan In the vastness of space and the immensity of time, it is my joy to share a planet and an epoch with Annie

Carl Sagan was the Director of the Laboratory for Planetary studies andDavid Duncan Professor of Astronomy and Space Sciences at Cornell University. He played a leading role in the Mariner, Viking and Voyager expeditions to the planets, for which he received the NASA medals for Exceptional Scientific Achievement and for Distinguished Public Service, and the international astronautics prize, the Prix Galabert. He served as Chairman of the Division for Planetary Sciencesof the American Astronomical Society, as Chairman of the Astronomy Section of the American Association for the Advancement of Science, and as President of the Planetology Section of the American Geophysical Union. For twelve years, he was Editor-in-Chief of Icarus, the leading professional journal devoted to planetary research. In addition to four hundred published scientific and populararticles, Dr Sagan was the author, co-author or editor of more than a dozen books, including Intelligent Life in the Universe, The Cosmic Connection, The Dragons of Eden, Murmurs of Earth, Broca’s Brain and the bestselling science fiction novel, Contact. He was a recipient of the Joseph Priestly Award ‘for distinguished contributions to the welfare of mankind’, and the Pulitzer Prize for literature. CarlSagan died in December 1996.

CARL SAGAN Cosmos

CONTENTS Introduction 1 2 3 4 5 6 7 8 9 10 11 12 13 The Shores of the Cosmic Ocean One Voice in the Cosmic Fugue The Harmony of Worlds Heaven and Hell Blues for a Red Planet Travelers’ Tales The Backbone of Night Travels in Space and Time The Lives of the Stars The Edge of Forever The Persistence of Memory Encyclopaedia Galactica Who Speaks forEarth? Appendix 1: Reductio ad Absurdum and the Square Root of Two Appendix 2: The Five Pythagorean Solids

INTRODUCTION The time will come when diligent research over long periods will bring to light things which now lie hidden. A single lifetime, even though entirely devoted to the sky, would not be enough for the investigation of so vast a subject . . . And so this knowledge will beunfolded only through long successive ages. There will come a time when our descendants will be amazed that we did not know things that are so plain to them . . . Many discoveries are reserved for ages still to come, when memory of us will have been effaced. Our universe is a sorry little affair unless it has in it something for every age to investigate . . . Nature does not reveal her mysteries once andfor all. - Seneca, Natural Questions, Book 7, first century In ancient times, in everyday speech and custom, the most mundane happenings were connected with the grandest cosmic events. A charming example is an incantation against the worm which the Assyrians of 1000 B.C. imagined to cause toothaches. It begins with the origin of the universe and ends with a cure for toothache: After Anu hadcreated the heaven, And the heaven had created the earth, And the earth had created the rivers, And the rivers had created the canals, And the canals had created the morass, And the morass had created the worm, The worm went before Shamash, weeping, His tears flowing before Ea: ‘What wilt thou give me for my food, What wilt thou give me for my drink?’ ‘I will give thee the dried fig And the apricot.’...