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17.1 The librarian who first measured the Earth Part I One morning the heralds spread the news through the town: King Ptolemy III Evergetes had appointed Eratosthenes of Cyrene librarian of the great library of Alexandria. Some people might have found it dull to be a librarian, but Eratosthenes was not despondent. He decided to read everything he could find on travels and on discoveries of the Earth’s secrets. Then he would write a big scientific book containing all the geographical knowledge of those times. This work, which Eratosthenes called Geographica, took up a great deal of time. Still sometimes the librarian would leave his quiet office and go out into the sunny streets of the city. He would make his way to the Alexandrian bazaar where simple folk argued and bargained. The royal librarian was wont to sit down somewhere in the shade of a shop wall and start a conversation with the visiting merchants. One of them said: “ Our town of Syene is the hottest place ever. They say there is no other such place on the sacred Earth. Here when we sit in the shade it seems a bit cooler. But in Syene there is a day once a year when there is no shade to be found . ” Eratosthenes was surprised. “ Wait, I don’t quite understand what you mean. A shadow may grow longer or shorter, but I’ve never seen there to be none at all. ” “ Nevertheless, in our Syene, on June 22 at mid-day you will find no shade at all, ” retorted the merchant stubbornly. “ Oh yes, on that day you can see the bottom of the deepest and narrowest well. Believe me”. Part II The stranger’s story made Eratosthenes fall to thinking. He sought out and reread manuscript after manuscript, trying to understand: “ How can such a thing be? ” It was the works of the great Aristotle that suggested the answer. That wise philosopher asserted that the sun illuminates different parts of the Earth’s surface differently and that its rays have different angles of incidence because the Earth is a sphere; hence, the length of the sun's shade cannot be the same everywhere at the same time. Now what if we turn to the Sun for help in measuring the size of the globe? That is just what the Alexandrian librarian decided to do. He had no intention of making a long journey to measure the distance from one town to another step by step. His idea was to measure the Earth without leaving the little courtyard of the Alexandrian library. He constructed a special scatha or bowl, resembling a greatly enlarged half nutshell. At the centre of the bowl he fixed a column. Then he set up his 87 invention in the library courtyard and waited for the longest day in the year. On June 22 the sun arose in the sky above Alexandria. At that moment the scientist measured the length of the shadow the column threw on to the bottom of the bowl. He found it to be one-fiftieth of the scatha circumference. At that same moment there was no shade at all at Syene (vicinity of the modern Aswan): there the sunbeams fell vertically. The distance between the two cities was 5,000 stadia (the stadium was a Greek unit of length) or 800 kilometres. Such would be the length of one of 50 equal arcs constituting the complete circumference of the Earth. From this Eratosthenes calculated the entire circumference to be 800 * 50=40,000 kilometres. Then by a simple calculation he found the radius of the globe to be equal to 6,370 kilometres. Since then investigators have measured the Earth’s surface many times, but their results always coincide in the main with the figures derived in ancient times by Eratosthenes. The space laboratories of artificial Earth satellites have also confirmed these figures. Thus, the Alexandrian librarian measured the earth correctly almost 2,200 years ago. 17.2 A Hook to the Earth Comparatively not so long ago our country as far as the Carpathians and the south Urals was covered with ice, as were also Canada and the north of the United States. This fact is beyond any shadow of doubt. About 12,000 years ago the ice melted: this is also an authentic fact. But why did it happen? Ludwig Seidler, a Polish scientist, made a careful study of the circumstances of this event. The explanation he found is based mainly on what would seem to be a rather unimportant fact. In north-eastern Siberia there are cemeteries of extinct animals where tens of thousands mammoths are buried in the permafrost layers. The flesh of these animals has been excellently preserved, because the animals lived under conditions of Arctic cold. But this is not so. Undigested remains of food were found in the stomachs of the dead mammoths, remains of cones and needles of spruce and larch, which do not grow in the north tundra. This means that the ancient elephants lived in a moderate climate and they perished from the unexpected cold. It means that a great catastrophe fell on the planet 12,000 years ago. What was this catastrophe? Ludwig Seidler thinks that the Earth collided with a very large cosmic body, which made it shudder and displace. The geographic poles quickly shifted 30 degrees in the direction of the action of the outer force. The North Pole moved out of Hudson Bay into its present position, and the “ice cap” shifted rapidly from Labrador to the mouth of the Yenisei, freezing a herd of mammoths. The equator changed its position accordingly. Previously it has passed through the highest peak in the world – Mount Everest. That is how some regions of our planet grew sharply colder, and others much warmer. That is how the climate changed unexpectedly. 88 Of course, this catastrophe made the waters of the World Ocean rush as a gigantic wave into the lowland regions of America and Europe, drowning the hypothetical Atlantica and tearing through Gibraltar into the Mediterranean Sea. All this is mentioned in the works of the ancient Greek chronicler Plato. Perhaps this was the basis for the biblical legend of the “world flood”. Some scientists think that in the past the geographical and magnetic poles coincided, but nowadays they do not because they have moved many hundreds of kilometres apart. But what if it is just that the magnetic axis has not yet caught up with the geographic axis, being closer as yet to their precatastrophic direction? The Polish scientist even indicated the landing site of the supposed planetoid, which had landed such a hook on the Earth, as boxers would say. He considered this site to be not far from the Bahama Islands. A daring, almost fantastic conclusion, isn’t it? 17.3 Gold mines under the sea Man is only just beginning to realize how much he must look to the sea. When we got to the bottom of the sea, we find things that no one dreamed existed until recently. Lands which were covered with water when the ice melted at the end of the Ice Age are rich in minerals. Off the South African coast, for example, is a place where there are five times the number of diamonds as in the mines on the land. One of these diamond mines on the sea of the bottom is near the mouth of the Orange River. Oil is brought from the bottom of the Caspian Sea near Baku. Sand with gold in it has been found off the Alaskan coast near Nome, and tin is mined off Thailand and Indonesia. But if man wants to continue gathering riches from the sea he is going to have to look after it. The effects of radio-activity, and even of household detergents are harmful to the creatures that live in the sea and can be harmful to the people who eat them. One recent discovery shows that there is now ten times more lead in the upper levels of the sea than there was forty years ago because lead from the high-octane petrol used in motor-cars goes into the atmosphere. 17.4 Getting into Deep Water The dark depths of the Gulf of Mexico, once frequented by only the sea creatures, are now alive with human activity. Miniature submarines and robot-like vehicles move around the ocean bottom while divers make their way around incredible underwater structures-taller than New York City skyscrapers but almost totally beneath the surface of the waves. Modern-day explorers are using technology worth of Jules Verne and Jakques Cousteau to find fresh supplies of oil and natural gas.Until recently, drilling in the Gulf was concentrated close to shore in water as deep as 9 km. But now the scientists are looking to hundreds of meters deep and 160 kilometres and more from land. The deep water research began in 1984. Since many American companies have built the world’s deepest production platforms of more than 100 stories high. |