Chapter 3 Characteristics, Laws and Conditions of the Earth

The ancients firmly believed: "The earth is a small black object, hanging alone in the universe." Strictly speaking, the human earth is actually not a "sphere", but an "ellipsoid", which is similar to a sphere, except that the two poles are slightly flattened.What are the "poles"? Take a sweater needle and poke straight through the middle of an orange or apple. The points where the needle goes in and out are the "poles" of the sphere.The two poles on the earth, one is at the top of the plateau (South Pole), and the other is at the bottom of the sea (North Pole).

Since the length of the central axis between the two poles of the earth is only 1/300th shorter than the diameter of the equator, the problem of "flatness" at the two poles of the ellipsoid can be completely ignored.If you are lucky enough to have a large globe with a diameter of 3 feet (you cannot buy such a large globe in the store, you can only find it in a museum), you will find that its north-south axis is only one-eighth shorter than its equatorial diameter. An inch, and unless it's been worked with uncommon precision, such a small difference is almost imperceptible. Of course, for those polar explorers and geographers, this gap cannot be ignored, but for the readers of this work, it is enough to know this.Even if it is a speck of dust, if it rotates, its two poles will naturally flatten.Maybe there's a device in your physics teacher's lab that will show you this.Go ask your teacher, or what a hassle it would be to do a field trip to the poles.

Everyone knows that the earth is a planet. The word "planet" comes from the Greeks.The Greeks have long observed (or thought they observed) that some stars are constantly moving in the universe, which they call "planets" (planets), or "wanderers" (wanderers); Those that don't move, they call them "fixed stars", because the Greeks didn't invent telescopes at that time, and it was impossible to observe the movement of stars.As for the origin of the word "star", it is impossible to verify it. It is probably related to the root of the Sanskrit word "scatter, sow, embellish": the stars dotted the sky, like small flames scattered in the sky. .What a beautiful and apt metaphor.

The earth revolves around the sun, absorbing the light and heat of the sun.Since the surface temperature of the sun reaches 6000 degrees Celsius, the volume of the sun is more than 700 times that of all the planets in the solar system. Therefore, the light and heat obtained by the earth are only a little bit, which is really insignificant. Don't be alarmed. People in ancient times believed that the center of the universe was the earth, which was a small piece of dry land surrounded by vast oceans, like Muhammad's wooden coffin and a broken kite, completely suspended in the air.Only a few foresighted Greek astronomers and mathematicians (the first to think without consulting priests) dared to question the theory.After several centuries of hard and persistent exploration, these pioneers came to the conclusion that the land under human feet is not a flat disc, but a round sphere, which is not standing still and isolated on the ground. The sky is not the center of the entire universe; on the contrary, it revolves around a larger sphere at a relatively fast speed—the sun is constantly revolving.

They also pointed out that, compared with the so-called static stars, those moving stars do not revolve around the earth. In fact, they are also planets, and they revolve around the sun together with the earth.Like the earth, they belong to the solar system family and follow the same laws of operation (this law determines the daily work and rest of human beings, including when to get up and when to go to bed), and move along their respective established orbits. If there is a deviation, it is bound to go to destruction . During the last 200 years of the Roman Empire, the intelligentsia had been able to accept this hypothesis because it was convincing.However, after the church came to power from the beginning of the fourth century, it was very dangerous to believe in this kind of thinking.Anyone who dares to claim that the earth is round will be in danger of life or death.However, we should not blame the church for this, because at that time, the earliest converts to Christianity were from the most ignorant social classes, and they were indoctrinated with the idea that the end of the world was approaching, and by that time, for the sake of their children People, Jesus will return to the place of suffering in glory to judge the good and evil in the world.These Christians are convinced that this is the only truth in the world, and they stand firm because of it.If Jesus really came the second time, then everything else is false, and the earth under human feet will be as flat as the church says, otherwise, Jesus will have to come twice , once to the Western Hemisphere and once to the Eastern Hemisphere.If so, it would be grotesque and blasphemous.Therefore, the earth can never be round.The church has spent nearly a thousand years sparing no effort to instill in its believers the idea that the earth is a flat disk and the center of the entire universe.As for the theory of the round earth in ancient Greece, the intellectuals at that time, some scholars in the monasteries and astronomers in the emerging cities did not give up, but they did not dare to discuss the theory of the round earth openly.They know very well that if they openly talk about the theory of the circle of the earth, it will not only break the peaceful life of thousands of ignorant people, but it will also be useless.

However, Christians gradually and had to accept the theory of the round earth.By the end of the 15th century, the society had generally agreed with the theory of the circle of the earth produced by ancient Greece.The theory of the circle of the earth is the result of a series of observations throughout the ages: First of all, when people are approaching a big mountain or a big ship, their tops are always seen first, and then gradually they become the whole picture.This is an indisputable fact. Secondly, no matter where people are, their field of vision is always circular.No matter looking at the land or the sea, the line of sight of people's eyes always moves in parallel. When taking a hot air balloon to the sky or standing on a high tower, people's vision will be much wider. The scope of the circle It also expanded a lot.If the earth were round, people would find themselves in the center of an elliptical field of vision; if the earth were square or triangular, the horizon would also be square or triangular.

Third, when a partial lunar eclipse occurs, the shadow of the earth appearing on the moon is also circular.Only round objects will cast round shadows. Fourth, since other planets and stars are spherical, why is the earth an exception among thousands of celestial bodies? Fifth, Magellan (Portuguese navigator, about 1480-1521. In 1519, under the order of the Spanish government, he led the fleet to sail around the world, and died halfway. In September 1522, the "Victoria" in the fleet returned to To Spain, completed the first human voyage around the world———Translator’s Note) The fleet sailed from east to west for a long time, and finally returned to the place of departure, and the experience of Captain Cook was the same. His expedition team traveled from west to west. Sailing eastward, the survivors eventually returned to their hometowns.

Finally, as one walks toward the North Pole, the familiar constellations (the ancient constellations of the zodiac) disappear one by one on the horizon, and as one approaches the equator, these constellations become more and more apparent. higher. These facts fully prove irrefutably that the earth under human feet is a sphere. Of course I can list a lot of scientific data to prove it, but for ordinary people, they don't make much sense.Take light for example, the speed of light is 186,000 miles per second, and it circles the earth 7 times in a snap of a finger.It takes 8 minutes for the sun's light to reach the earth, but it only takes 3 minutes for Jupiter's light to reach the earth.However, it takes 4 years and 3 months for the light of the star closest to the solar system (Proxima Centauri) to reach the earth. The light of the North Star plays an important role in navigation, and the light of the North Star that reaches the earth set off as early as 40 years ago.

Go and imagine this distance, go and imagine how long a light year is, go and imagine the path traveled by a ray of light in a year, or go and imagine the distance of 365×24×60×60×186000 What a concept a mile is! Imagine it! I think that this astronomical number will make most people so dizzy that they just don't care about it. Or use the familiar train as an example to describe it: An ordinary tourist train runs day and night, and it takes 260 days to reach the moon, and much more days to reach the sun.If the train leaves from now (1932), it will take 2232 to reach the sun.It takes 8,300 years for the train to travel to Neptune, which is still insignificant, because it takes 75 million years for the train to travel to the nearest star outside the solar system, and 700 million years for the train to reach the North Star!It's been a long trip.If the average human life expectancy is 70 years as the standard, 700 million years means that the train will finally arrive at the station after 10 million generations of human reproduction!

Moreover, we are only talking about this part of the universe that we observe.In Galileo's time, astronomers used a simple device to observe the sky and made a series of important discoveries.Compared with that era, the current telescope has improved a lot, but there are still many unsatisfactory places. It was not until human beings enlarged the lens by 1000 times that we made great progress in astronomical research.It can be seen from this that the universe that human beings talk about is really only "a small part of the vast universe observed by human beings with the naked eye or with the help of photosensitive film."About the rest of the universe, about the unobserved world, human beings still don't know anything, and dare not even think about it!

In the vast sea of ​​stars, there are two close neighbors to the home of human beings—the sun and the moon, both of which affect the survival of human beings, which is obvious and straightforward.Every 24 hours, the sun provides light and heat to half of life on earth.The moon, which is closest to human beings, affects the movement of the sea, causing a strange phenomenon of water flow called "tide" in the sea. Although the moon is far smaller than the sun in terms of volume (if the sun is compared to a ball with a diameter of 3 feet, then the earth is like a green bean, and the moon is just a needle point), but the moon's gravitational force on the earth is greater than that of the sun. The gravitational force on the earth is much stronger than that of the sun, which is due to the fact that the earth is very close to the moon. If the entire earth were made of solid matter, the gravitational pull of the moon would be imperceptible.However, the oceans cover three-quarters of the Earth's surface, and just as iron filings on paper move side to side with a magnet, sea water ebbs and flows with the Moon orbiting the Earth. Under the tug of moonlight, a band of water hundreds of miles wide was running day and night.When it rushes to the bay, port or estuary, it is like a beast suddenly bound, and it is even more violent, stirring up huge waves as high as 20 feet, 30 feet or even 40 feet.It is dangerous to sail in such places at this time.When the moon and the sun happen to be in the same direction of the earth, the gravitational pull on the sea water is stronger, and the so-called "spring tide" appears.A spring tide is like a minor flood in many places. The earth is surrounded by a layer of nitrogen and oxygen. The atmosphere made of this mixture of nitrogen and oxygen is "air", and it is about 300 miles thick.The air and the earth are inseparable, just like the peel of an orange protects its orange flesh, and they work together. About a year ago (that is, in 1931), a special hot air balloon carrying a Swiss professor rose to an altitude of 10 miles.This is the first time humans have entered the atmosphere.Although this is a great feat of mankind, the earth's atmosphere is still 290 miles thick waiting to be explored by mankind. The atmosphere, the surface, and the oceans together form a laboratory that produces all kinds of climates, producing winds, storms, blizzards, and droughts.Since human life is influenced by climate all the time, we should discuss climate in detail. Soil temperature, prevailing wind and air humidity are the three major elements that affect climate change. The original meaning of "climate" is "the slope of the earth's surface".Very early on, the ancient Greeks noticed that the closer one gets to the poles, the more the Earth's surface "tilts" and its temperature and humidity vary more. The meaning of the word "climate" later extended from specifically referring to a region to expressing the climate conditions of any region. Now when we speak of the "climate" of a country or region, we mean the average weather conditions that prevail in that country or region during the four seasons of the year. Let me talk about the strange wind first.In the process of human civilization, the role played by the wind is very important.If the trade winds prevailing in the tropical seas had not existed, the discovery of the American continent would have waited for the invention of the steamship; and if the moist winds had not existed, California and the countries around the Mediterranean would never have been able to enjoy such prosperity as they do today. Neighbors to the north were left far behind.Not to mention the flying sand and rocks that come with the wind, they are like a huge invisible sandpaper, even if you want to smooth the most majestic mountain on the earth, it only takes a few million years. "Winding, circling, roundabout" forward is the original meaning of "wind", and the wind is an airflow that "roundabouts" from one place to another.So why does the air flow weave from one place to another? This is because the air in some places is warmer and lighter than the air in other places, so it keeps moving upwards.As the warmer, lighter air rises, a vacuum forms beneath it, and cooler, heavier air fills the void. 2,000 years ago, the ancient Greeks said that "nature hates a vacuum", just like water and humans, air does not like a vacuum. How to create hot air in a room?It is enough to light a stove.And the sun is a stove in the vast universe, and the planets in the solar system are the rooms waiting for it to go to warm.On the earth, the hottest place is of course the equatorial region closest to the "stove", and the coldest place is the north and south poles farthest from the "stove". The air in the "room" oscillates violently because of the "stove", forming a circular flow.After the air is heated, it continues to rise, until it rises to the "ceiling" (the top of the atmosphere), but at the same time it is gradually farther away from the heat source, so the temperature is constantly decreasing.The cooling air gradually became heavier and flowed back to the ground again.As the cold air got closer to the ground, it got closer and closer to the "stove", so it was baked hot and light again, and went up again.It goes on and on like this until the "stove" goes out.However, when the "stove" is burning, the "wall of the room" absorbs a large amount of moisture, which can maintain the humidity of the "room", and the main factor that determines the length of the heat preservation time is the material of the "wall". On the earth, this "wall" is the land on which human beings live.Compared with swamps filled with rainwater, sand and stone absorb heat faster and dissipate heat faster.So soon after the sun goes down, the desert can be chilly, while the forest is still balmy and comfortable for hours after nightfall. Water is a veritable heat storage tank.Therefore, the climate of countries near the sea and islands is milder and more balanced than that of landlocked countries. As the "stove" of the earth, the sun provides heat to the earth for much longer in summer than in winter, and the sun in summer is hotter, so summer is hotter than winter.However, there are other factors that affect the sun's heating effect.In winter, if you use a small electric heater to heat the bathroom, you will find that the angle of the electric heater is the main determinant of the bathroom temperature.The same goes for the sun.In the tropics, the sun is almost directly on the ground.In the forests of Africa or on the wilderness of South America, the sun's rays a hundred miles wide can fall evenly on a surface a hundred miles wide, and release all its heat there, without any waste.At the poles, however, sunlight falls obliquely onto the surface.A beam of sun-covered hard soil or ice crust 100 miles wide (an illustration will tell more than a long story) would be 200 miles wide, so the solar energy received by the poles is discounted by half.This is like a heating stove that is only enough for 6 rooms to warm 12 rooms, it will definitely be powerless and cannot achieve the same effect. In fact, the working procedure of the sun, the space "stove", is more complicated, because it also needs to keep the atmosphere around the earth at a constant temperature.This constant temperature project is not completed directly by the sun, but by the earth itself. Why is the top of the mountain so cold?When sunlight penetrates the atmosphere to shine on the earth, it does not directly affect the temperature of the earth's protective clothing.It is the earth that first stores the sun's heat, and then delivers it to the atmosphere bit by bit.So the higher the mountain, the less surface heat it gets.If sunlight directly heats the atmosphere, and the atmosphere heats the surface, then the mountaintops would not be covered with snow. Now go deeper into the difficulty of the problem.Air is not really "empty", but is composed of many substances and has weight, so the pressure on the air in the lower layers of the atmosphere is greater than that in the upper layers.If you wanted to flatten a leaf or a flower, you would sandwich it in a piece.You know, to get the maximum pressure on this one, put 20 more on top of it.By the same token, the air pressure around humans is greater than we think, at 15 pounds per square inch.If we didn't have air at the same pressure inside us, the atmosphere would crush us flat.Even so, the average person was under 30,000 pounds of stress. At 30,000 pounds, that's a lot of weight, and if you're in doubt, try lifting a pickup truck. Galileo's student, Torricelli, told mankind that the atmospheric pressure is also constantly changing. At the beginning of the 17th century, Torricelli invented the barometer. With this well-known instrument, humans can measure the air pressure anytime and anywhere. As soon as the Torricelli barometer was put on the market, it was used for various experiments.It has been found that the air pressure decreases by 1 inch for every 900 feet increase in altitude.Other new discoveries followed, laying the groundwork for the development of meteorology, the science that studies atmospheric phenomena and predicts the weather. Is there any necessary connection between the level of air pressure and the direction of the prevailing wind?Some physicists and geographers are beginning to have doubts.In order to discover the operating laws of these prevailing winds, human beings collected data and summarized the laws. It took several centuries before they finally came to a conclusion.Studies have shown that on the Earth's surface, some areas have higher air pressure than sea-level average pressure, while other areas have lower air pressure than sea-level average air pressure.High pressure areas and low pressure areas are formed naturally in this way.The airflow flowing from the high pressure area to the low pressure area forms the wind, and the pressure contrast between the two pressure areas determines the speed and strength of the wind.If the air pressure in the high-pressure area is high and the air pressure in the low-pressure area is low, the wind will be very strong, and a storm, hurricane, or tornado will occur. The wind not only keeps the atmosphere of the human home circulating and maintains good ventilation, it also plays another important role-bringing rain to the earth.If there is no rain on the ground, animals and plants cannot grow normally. Water in the oceans, inland lakes, and continental snowfields is evaporated by heat, forming water vapor in the air.Hot air can easily carry a large amount of water vapor in motion until its temperature gradually drops and becomes cold air.In this way, part of the water vapor condenses due to the cold, becomes rain, snow or hail, and falls to the surface. The wind in an area almost completely determines the amount of precipitation in that area.If mountains separate the coastal area from the inland (this is a common landform), the wind is forced to rise in the mountains (lower air pressure in the mountains), and the higher it is from sea level, the cooler it is, and the water vapor It will turn into rain and snow and fall to the ground, so the coastal areas will be very humid.When the wind blows across the mountains to the other side, it is already a dry wind without any moisture. Because of the huge heat on the surface of the tropics, the air rises very high, and the water vapor condenses when it is cold, forming torrential rains. Therefore, the rainfall in this area is abundant and stable.Because the sun does not always shine directly on the equator, but is sometimes northerly and sometimes southerly, so there are four seasons in the equatorial area.There are two seasons of continuous torrential rain, while the other two seasons of no rain. The most unlucky are those places, which are under the control of air currents flowing from cold to warm regions all the year round.This is because when the wind blows from a cold area to a warm area, although their ability to absorb water gradually increases, the water vapor in the air will not condense to form rainfall, so such areas will not appear once in 10 years. It rained twice, and it turned into a dry desert. As for wind and rainfall, that's all for now, and their specific conditions will be discussed in later chapters.Then, a brief introduction is given to the condition of the earth itself and the hard rocky crust under human feet. There have been many theories about the internal structure of the earth, and until now, none of them has been completely convincing. How high has man gone? How deep has man gone? Let's look at reality first. On a 3-foot-diameter globe, the world's tallest mountain, Mount Everest, is no more than a sheet of paper thick, while the deepest part of the ocean (in The eastern side of the Philippine Islands) (Mariana Trench ---- Translator's Note) looks like the perforation on a postage stamp.Man has never explored the depths of the ocean, nor climbed the summit of Mount Everest.Human beings have carried hot air balloons and aircraft to fly high into the sky, and the altitude is only a little higher than Mount Everest, but there are still 97% of the atmosphere waiting to be explored by humans.As for the ocean, less than 3% of the depth of the Pacific Ocean has been reached by humans.Moreover, if the highest peaks of all continents were crammed into the deepest depths of the ocean, the summit of Mount Everest would still be thousands of feet below sea level.It can be seen that the top of the mountain is not as good as the abyss of the deep sea.Why is this so? Human beings have not yet been able to answer. Modern scientific knowledge cannot explain these puzzling facts.Human beings still know nothing about the past and future of the earth's crust.We already know that volcanoes are not the eruptions of hot matter that are considered to be inside the earth, so we don’t need to study volcanoes any more, hoping to find evidence of the earth’s interior structure from them (human ancestors had such fantasies) ).If my analogy is not particularly annoying, a volcano is like an abscess in the human body. Although it rots and hurts, it is only a local problem, not an internal problem (due to the limitation of the scientific development level at that time, the author came up with the following Wrong understanding. In fact, volcanoes are formed by the ejection of high-temperature materials such as magma inside the earth——Translator’s Note). There were originally 400 active volcanoes in the world, but with the passage of time, some active volcanoes gradually lost their vitality, and then simply retired and became ordinary mountains.There are still about 320 active volcanoes. In fact, most of the crustally active areas are close to the ocean. For example, Japan (according to seismic monitoring, this country has four slight volcanic tremors per day, and 1,447 earthquakes per year) is an isolated island country. Lakatoa – The worst casualties of recent volcanic eruptions have been in the middle of the ocean.Therefore, the vast majority of volcanoes are located in coastal areas. Since most volcanoes are very close to the ocean, people take it for granted that volcanic eruptions are caused by seawater seeping into the interior of the earth, causing a strong explosion, causing lava, steam and other substances to erupt and overflow, resulting in disasters.However, later humans discovered that there are still some volcanoes that are quite active, but they are thousands of miles away from the ocean, so the above-mentioned assumptions are self-defeating. In addition, what do humans know about the surface of the earth? In the past, people always compared things that are eternal and unchanging to rock solid.However, modern science does not support this metaphor. It tells people that rocks are not only in continuous growth, but also in continuous change.The mountains are being shortened by the wind and rain at a rate of 3 inches every millennium, and if this erosion had not been counteracted by counteracting forces, all mountains would have long ago disappeared.It would take only 116 million years to even level the Himalayas.Therefore, this reaction force not only exists, but also has great power. To get an idea of ​​the surface movement, take half a dozen clean handkerchiefs, lay them flat on a table, and slowly squeeze the handkerchiefs from the sides toward the center.You will see that this pile of handkerchiefs has formed a mass of grotesque folds, some raised like peaks, some sunken like valleys, and some overlapping like hills.These folds are like the Earth's surface.The earth's crust is a part of the huge monster of the earth. When it runs at a high speed in the universe, its heat is also continuously lost. As the heat is lost, it will slowly shrink, and then fold and deform, just like a pile of squeezed together handkerchief. According to the best current guesses (and no more than guesses), the Earth has shrunk about 30 miles in diameter since its formation. 30 miles as a straight-line distance, you may think that this is not too long, but please don't forget that what we are facing is a huge curved surface.The surface area of ​​the earth is 196.95 million square miles, and if its diameter were suddenly shortened by a few yards, a catastrophe would ensue, sufficient to destroy the entire human race. Fortunately, the miracle of nature is created bit by bit, and she delicately keeps the balance of the whole world.If she were to dry up one ocean (the American salt lakes are drying up rapidly, and Lake Constantine in Switzerland will disappear in 100,000 years), and in another place she would create a new ocean; (After 613 million years, the Alps in the center of Europe will become as flat as the Great Plains of the United States), and she will create another mountain in another corner of the earth.This is human wishful thinking at least.Of course, we can't observe the subtle changes in the movement of the earth's crust, because she goes on so long and slowly. However, this is not always the case.Although nature itself is a slow person, sometimes she is frighteningly fast and frightening under the instigation and promotion of human beings.Now that man has evolved into such a civilized state, such things as steam engines and explosives have been invented, and earth-shaking changes have taken place on the surface of the earth in an instant.If our great-grandfathers could come back to spend the festive season with us, they would not recognize these pastures and gardens where they once lived.Due to the greedy demand for the forest, the green clothes of one mountain after another were ruthlessly stripped by humans, and the continuous green hills became an ancient wilderness because the forests and shrubs were cut down.As the forest disappeared, the rains washed away the fertile soil that had been firmly anchored to the rock surface, exposing hideous ridges that threatened the surrounding area.The tree roots and turf were gone, and the rainwater had nowhere to hide, so it had to turn into a torrent, rushing down the valley from the top of the mountain, rampaging on the plain, and the people it passed were devastated. This is by no means alarmist.During the glacial period, we don't have to go to see the thick ice and snow laid by her magical power on the Nordic and North American continents, and the cliffs left in the various mountainous areas. We only need to go back to the Roman era to see those for the first time. How did the first-class pioneers (were they not the "most practical people" in ancient times?) destroy all the conditions that could maintain a balanced temperature on that peninsula in less than five generations, and completely "reform" them The climate of that peninsula.In South America, the industrious and humble Indians cultivated their fertile terraced fields for generations, but under the iron heel of the Spaniards, this fertile land finally turned into a wasteland.This is a fact that happened right before our eyes, so there is no need to waste words. Of course, the easiest way to exploit and enslave the indigenous people is to cut off their food sources.The U.S. government can be called an "example" in this regard.They killed the American bison, so those brave and fearless Indian warriors were easily turned into dirty, lazy reservations to educate the residents.However, these cruel and stupid measures will eventually come back to punish the colonists themselves.If you know what's going on in the Great Plains and the Andes in the U.S., you'll understand that it's the U.S. government's own fault. The land is the source of human life.Fortunately, those in power finally realized the seriousness of this problem.Today, governments are no longer turning a blind eye to this shameless invasion of the land.Although human beings are helpless to the overall movement of the earth's surface, they can carry out small local transformations on the earth's surface within a certain range, so that the earth can bear more nectar and the oasis will be less covered with yellow sand.Humans may not know anything about the depths of the Earth's crust, but we at least know something about its exterior.We can apply this accumulated knowledge to the benefit of all mankind. As of today, 75% of the earth's surface is still home to human beings --- the ocean world is neither inhabitable nor capable of transformation by human beings.These surfaces are covered by seawater of varying depths.The shallowest place is only 2 feet, and the deepest place is the world's deepest trench located east of the Philippine Islands, which is as deep as 35,000 feet. Human beings divide these sea waters into three parts.The largest body of water is called the Pacific Ocean, which is 68.5 million square miles, the Atlantic Ocean, which is 41 million square miles, and the Indian Ocean, which is 29 million square miles.In addition to oceans, there are 20 million square miles of inland seas, and 10 million square miles of rivers and lakes.No matter in the past, future or present, these waters are not the habitat of human beings, unless human beings can also grow another piece of gills like their ancestors millions of years ago. The total land area of ​​human beings is 57.51 million square miles, but in these human-disposable land resources, those "lands" that cannot be developed and utilized should be deducted --- 5 million square miles of desert, 19 million square miles of land like Siberia There is not much use value of the wilderness, and there is still a vast area that cannot be used, either because the altitude is too high (such as the Himalayas and the Alps), or because the temperature is too low (such as the polar regions), or because the humidity Too large (such as the swamps of South America), or due to dense forests (such as the jungles of central Africa).This sense of land crisis makes people believe that if God gives the land to mankind, we will cherish it even more.Thus, that vast expanse of ocean covering a vast resource of land seems at first glance to be a colossal waste, and one which mankind should chagrin. However, without the vastness of the ocean to act as a thermal reservoir, human survival is very questionable.Geological relics tell people that in prehistoric times, the land area of ​​the earth was once quite large, and the area occupied by the ocean was much smaller than it is now, but the earth was very cold at that time.At present, the area ratio of land and ocean on the earth is 1:4, which is an ideal distribution ratio.As long as this ratio does not change, the current climate can be maintained for a long time, and human beings will be able to live and work in peace and contentment forever. Like the Earth's crust, the oceans that surround the Earth are in constant motion.The gravitational force of the sun and the moon pulls the seawater, causing the seawater to rise continuously, and part of the rising seawater is evaporated into water vapor under the action of heat energy, and then, the severe cold in the Arctic region turns them into ice.From a practical point of view, since atmospheric currents (winds) affect the ocean, they are the most direct natural factors affecting human life. When you blow on a pot of soup, the soup swings away from your mouth.Similarly, when an atmospheric current blows continuously to the surface of the ocean for many years, the sea water will "drift" forward in the direction from which the atmospheric current blows.If several atmospheric currents from several directions blow to the ocean at the same time, these currents will cancel each other out.But when the winds are more steady, like those blowing from either side of the equator, the drifts they create can become true ocean currents.These ocean currents have had an important impact on the history of mankind, creating one piece after another of pleasant paradise for mankind.If there is no ocean current, some places may be a world of severe cold, and like Greenland, a world of ice and snow. This map of ocean currents (many ocean currents do act like rivers) shows where they are located.太平洋中最重要的洋流是日本暖流(蓝色盐洋流)，它是由一股从北向东吹来的信风所形成的。在日本海完成了它的使命之后，这条洋流就横跨北太平洋，把它的祝福送到了阿拉斯加，减弱那儿的寒冷，让人类在那儿居住得更加适合，然后，它又转锋南下，在加利福尼亚创造出了宜人的气候。 说到洋流，就不能不说及墨西哥湾暖流。这是一条神秘的洋流，它有50英里宽，2000英尺深。在漫长的岁月里，它不仅把墨西哥湾的温暖源源不断地提供给北欧，还把富庶与繁荣带给了英格兰、爱尔兰和北海沿岸诸国。 墨西哥湾暖流颇富传奇色彩。它从北大西洋涡流发源。而北大西洋涡流更似一种漂流，而不是一种洋流。它是大西洋中部的一个巨大的旋涡，不停地旋转着，把半凝滞的海水卷入旋涡中心，里面裹带着成千上万条小鱼和浮游生物，就像一片藻海。在人类早期的航海史上，这股涡流扮演了一个重要角色。中世纪的水手们坚信，一旦航船被信风(北半球的东风)吹进了这一片藻海之中，就会有去无回了：航船一旦陷入藻海，方向就迷失了，因为又饥又渴，船上的水手会慢慢地死去，而在无云的晴空下，阴森的死船就在那儿永远地上下漂浮，如同一个无声的死亡警告，恐吓着那些胆敢冒犯神灵的人。 藻海的故事很有中世纪的古韵遗风，与但丁的地狱之旅极为相像。然而当这片沉寂的海水被哥伦布（美洲大陆的发现者，意大利航海家， 1451—1506。出生在一个寓居于热那亚的西班牙犹太织布工家庭。一生四度远航，为欧洲开拓了新殖民地。———译者注）的船队安然穿过之时，这个关于无边藻海的故事就变得更离谱了。但是，对许多人来说，直到今天，它仍是一个神秘而恐怖的名字。可是，实际上，它远不如纽约中央公园的那个天鹅池令人神往。 再说说墨西哥湾暖流。北大西洋涡流有一部分最后流进了加勒比海，并与从非洲海岸西行而来的一股洋流汇合。这两道巨流合二为一，就在加勒比海溢起来了，气势汹汹地朝墨西哥湾直奔而去。 这么多的海水墨西哥湾也盛不下来，墨西哥湾就把佛罗里达与古巴之间的海峡当做一个水龙头，将这股热流(华氏80°)从“水龙头”里喷泻而出，墨西哥湾暖流就这样形成了。古代航船为什么对墨西哥湾暖流敬而远之呢？一个原因就是冲出水龙头的墨西哥湾暖流奔腾前行，时速达5英里，严重影响航速。航船宁可绕道而行，也不愿意在墨西哥湾暖流逆流而进。 墨西哥湾暖流从墨西哥湾出发，沿着美国东海岸一路北上，遇阻之后才向东折向而行，横穿北大西洋。它在纽芬兰大浅滩附近，同自己的支流拉布拉多寒流汇合到一起。而拉布拉多寒流来自格陵兰岛的冰山区，刚刚南下到此，水温冷冰冰的，而墨西哥湾暖流则温暖而热情洋溢，这两股巨流的突然遭遇，茫茫大雾顿时升腾而起，以致这一片水域因此而臭名远扬。另外，还有大量的冰山漂浮在这片洋面上，在过去半个世纪的航运史上，它们也是臭名昭著。这些冰山本来是格陵兰岛上的坚硬的冰川(冰川覆盖了这个岛90％的土地)，但被夏日的骄阳生生地从岛上割了下来，巨大的冰山随着洋流缓缓向南飘来，最后混入到了墨西哥湾暖流和拉布拉多寒流汇合时所形成的巨大涡流之中。 这些冰山在海面上缓缓地旋转着，并慢慢地溶化，变小。但是，最危险的冰山就是处于溶化状态中的冰山，因为人们看到的只是残存在水面上的冰山上部，对深藏在水下的那些张牙舞爪的冰山下部却是看不见的，但冰山下部能够轻而易举地将航船的铁壳刺穿，就像一把利刃切黄油一样简单。如今，这一片海域已成禁地，所有海船都绕道而行，而美国巡逻舰队(专门负责侦察冰山，费用由各国共同承担)则在此观察瞭望，把小冰山炸毁，一有大冰山出现，就向来往船舶发出警告。然而，这片海水里有来自北冰洋的鱼群，因此渔民却对这一片海域情有独钟。这些鱼群习惯了拉布拉多寒流的低温，猛然进入到墨西哥湾暖流的温水中就十分不悦，正当它们还在犹豫是重返北极呢还是留在温暖的墨西哥湾时，这些迟钝的鱼儿就已被法国渔夫网到自己的渔船上。这些法国渔夫的祖先光临过美洲大浅滩比其他人早了好几百年。圣皮埃尔岛和密克隆岛———离加拿大海岸不远的两个小岛，它们不仅是200年前占领了北美大陆相当大地盘的庞大法兰西帝国的最后两块领地，而且，它们还是诺曼底渔民的勇敢的见证者。早在哥伦布出生前150年，这些诺曼底渔民就造访过美洲东海岸。 在离开“冷墙”(由墨西哥湾暖流和拉布拉多寒流的温差相撞而成的)之后，墨西哥湾暖流又继续向北流去，悠闲自在地横跨了大西洋，像一把扇子一样在西欧海岸散开。它拍打着西班牙、葡萄牙、比利时、爱尔兰、荷兰、法国、英国、丹麦和斯堪的纳维亚半岛的海岸，把无比温和的气候送给了这些国家和地区。在它的人道主义使命完成之后，这股夹裹着比世界上所有大江大河水量还多的海水的神奇的洋流就在北冰洋的怀抱之中消失了。北冰洋自然也装不下如此多的海水，于是，它也只好倾倒出去，这样，格陵兰洋流就产生了，而前面提到过的拉布拉多寒流就是格陵兰洋流的孩子。 这是一个多么有趣的故事啊！ 我很想再说下去，但这一章的篇幅已容不下更多的笔墨了。 这一章只是一个背景———关于气象学、海洋学和天文学的背景，在这样的背景之下，这场剧中的各个角色将逐一登台亮相。 现在让帷幕暂时落下。 当幕布再次升起时，新的一幕剧就开始了。 下一幕将告诉人们，在山川、海洋、荒漠中，人类是怎样学会了寻找道路的。在我们将这个世界称之为“人类的家园”之前，这里的一切都有待于人类去征服。 现在，帷幕渐渐升起来了。