SCIENCE AND SOCIETY, 2nd Edition John Avery H.C. Ørsted Institute, Copenhagen, 2005 2 Contents 1 THE BEGINNINGS OF CIVILIZATION 5 2 ANCIENT GREECE 19 3 THE HELLENISTIC ERA 43 4 CIVILIZATIONS OF THE EAST 59 5 SCIENCE IN THE RENAISSANCE 73 6 GALILEO 95 7 THE AGE OF REASON 105 8 THE INDUSTRIAL REVOLUTION 129 9 EVOLUTION 151 10 VICTORY OVER DISEASE 167 11 ATOMS IN CHEMISTRY 181 12 ELECTRICITY AND MAGNETISM 191 13 ATOMIC AND NUCLEAR PHYSICS 205 14 RELATIVITY 229 15 NUCLEAR FISSION 243 3 4 CONTENTS 16 HIROSHIMA AND NAGASAKI 259 17 GENESPLICING 279 18 ARTIFICIAL INTELLIGENCE 301 19 CARING FOR THE EARTH 323 20 LOOKING TOWARDS THE FUTURE 341 Chapter 1 THE BEGINNINGS OF CIVILIZATION Early ancestors of man Almost three million years ago, manlike creatures lived on the shores of Lake Rudolf in Kenya. The skull of one of these early “homenoids” was found in 1972 by Richard E. Leakey. Pouring fine sand into the reconstructed skull, Dr. Leakey and his associates measured the brain capacity as 800 c.c. - considerably less than the modern brain volume of 1400 c.c., but still remarkably large considering the early date of the skull. Potassium-argon dating of the volcanic ashes in which the skull was found established its age as approximately 2.8 million years. At the Oldavai Gorge in Tanzania, not far from Lake Rudolf, Louis and Mary Leakey (Richard Leakey’s father and mother) discovered many remains of a somewhat more advanced homenoid which they called Homo habilis. Among these remains, which were shown to be 1.8 million years old, Louis and Mary Leakey found many chipped stones, probably representing tools and weapons used by Homo habilis. The discoveries of the Leakey family, as well as those of Raymond Dart and Robert Broom, indicate that the early evolution of the human race probably took place in Africa. The early ancestors of man seem to have been hunter-gatherers living in small bands on the East African grasslands. 5 6 CHAPTER 1. THE BEGINNINGS OF CIVILIZATION Terra Amata We catch another glimpse of early man at the Terra Amata site at Nice in Southern France, where 300,000 years ago, in a warm period between the Mindel and Riss glacial eras, a small tribe came every summer to spend a few weeks hunting and food-gathering on the shore of the Mediterranian. The huts which these early people built on their brief summer visits to the beach are among the earliest man-made dwellings ever discovered. They were between 26 and 29 feet long, and were built in an oval shape out of leafy saplings leaned against a central ridge pole. The central ridge pole in each hut was supported by vertical tree trunks embedded in the sand. Around the oval perimeter of the huts were walls of large stones for protection against the wind, and inside the huts were hearths on which small fires were built. (This is almost the earliest use of fire known, although earlier hearths have been found in strata of the Mindel ice age at Vertesz¨olos in Hungary.) Water for the camp came from a nearby spring. The level of the Mediter- ranian Sea was then 85 feet higher than it is today. It covered most of the plane of Nice, and near the camp it had cut a small cove with a sandy pebble- strewn beach into the western slope of Mount Boron. On the slopes of the mountain grew heather, sea pine, Aleppo pine and holm oak. A human foot- print nine and one-half inches long is preserved in the sand of the ancient dune. Evidence shows that these summer visitors of 300,000 years ago spent their time gathering shellfish, hunting and making tools. Among the animals which they hunted were stag, an extinct elephant, wild boar, ibex, rhinoceros and wild ox. They stayed at Terra Amata only a few weeks each year, and then continued their travels, following the migrations of the animals which they hunted. The Soultrian and Magdalenian cultures In the caves of Spain and Southern France, not far from the Terra Amata site, are the remains of vigorous hunting cultures which flourished at a much later period, between 30,000 and 10,000 years ago. The people of these upper paleolithic cultures lived on the abundant cold-weather game which roamed the southern edge of the ice sheets during the Wurm glacial period: huge herds of reindeer, horses and wild cattle, as well as mammoths and wooly rhinos. The paintings found in the Dordogne region of France, for example, 7 combine decorative and representational elements in a manner which con- temporary artists might envy. Sometimes among the paintings are stylized symbols which can be thought of as the first steps towards writing. In this period, not only painting, but also tool-making and weapon- making were highly-developed arts. For example, the Soultrian culture, which flourished in Spain and southern France about 20,000 years ago, pro- duced beautifully worked stone lance points in the shape of laurel leaves and willow leaves. The appeal of these exquisitely pressure-flaked blades must have been aesthetic as well as functional. The people of the Soultrian cul- ture had fine bone needles with eyes, bone and ivory pendants, beads and bracelets, and long bone pins with notches for arranging the hair. They also had red, yellow and black pigments for painting their bodies. The Soultrian culture lasted for 4,000 years. It ended in about 17,000 B.C. when it was succeeded by the Magdalenian culture. Whether the Soultrian people were conquered by another migrating group of hunters, or whether they themselves developed the Magdalenian culture we do not know. The agricultural revolution Beginning about 9,000 B.C., the way of life of the hunters was swept aside by a great cultural revolution: the invention of agriculture. Starting in western Asia, the neolithic agricultural revolution swept westward into Europe, and eastward into the regions which are now Iran and India. By neolithic times, farming and stock breeding were well established in the Near East. Radio-carbon dating shows that by 8,500 B.C., people living in the caves of Shanidar in the foothills of the Zagros mountains in Iran had domesticated sheep. By 7,000 B.C., the village farming community at Jarmo in Iraq had domesticated goats, together with barley and two different kinds of wheat. At Jerico, in the Dead Sea valley, excavations have revealed a prepottery neolithic settlement surrounded by an impressive stone wall, six feet wide and twelve feet high. Radio-carbon dating shows that the defenses of the town were built about 7,000 B.C.. Probably they represent the attempts of a settled agricultural people to defend themselves from the plundering raids of less advanced nomadic tribes. By 4,300 B.C., the agricultural revolution had spread southwest to the Nile valley, where excavations along the shore of Lake Fayum have revealed 8 CHAPTER 1. THE BEGINNINGS OF CIVILIZATION the remains of grain bins and silos. The Nile carried farming and stock- breeding techniques slowly southward, and wherever they arrived, they swept away the hunting and food-gathering cultures. By 3,200 B.C. the agricul- tural revolution had reached the Hyrax Hill site in Kenya. At this point the southward movement of agriculture was stopped by the great swamps at the headwaters of the Nile. Meanwhile, the Mediterranian Sea and the Danube carried the revolution westward into Europe. Between 4,500 and 2,000 B.C. it spread across Europe as far as the British Isles and Scandanavia. Mesopotamia; the invention of writing In Mesopotamia (which in Greek means “between the rivers”), the settled agricultural people of the Tigris and Euphraties valleys evolved a form of writing. Among the earliest Mesopotamian writings are a set of clay tablets found at Tepe Yahya in southern Iran, the site of an ancient Elamite trading community halfway between Mesopotamia and India. The Elamite trade supplied the Sumarian civilization of Mesopotamia with silver, copper, tin, lead, precious gems, horses, timber, obsidian, al- abaster and soapstone. The practical Sumerians and Elamites probably in- vented writing as a means of keeping accounts. The tablets found at Tepe Yahya are inscribed in proto-Elamite, and radio-carbon dating of organic remains associated with the tablets shows them to be from about 3,600 B.C.. The inscriptions on these tablets were made by pressing the blunt and sharp ends of a stylus into soft clay. Similar tablets have been found at the Sumarian city of Susa at the head of the Tigris River. In about 3,100 B.C. the cuneiform script was developed, and later Meso- potamian tablets are written in cuneiform, which is a phonetic script where the symbols stand for syllables. Mesopotamian science In the imagination of the Mesopotamians (the Sumerians, Elamites, Baby- lonians and Assyrians), the earth was a flat disc, surrounded by a rim of mountains and floating on an ocean of sweet water. Resting on these moun- tains was the hemispherical vault of the sky, across which moved the stars, 9 Figure 1.1: Cuneiform writing was developed in Mesopotamia c.a. 3,100 B.C. It was a phonetic script in which the symbols stood for sylables. Tablets were made by pressing the end of a stylus into soft clay. The clay tablets were then dried and baked to make them permanent. 10 CHAPTER 1. THE BEGINNINGS OF CIVILIZATION the planets, the sun and the moon. Under the earth was another hemisphere containing the spirits of the dead.