Worlds within Worlds First of all let us consider the earth (that is to say, the world) as a planet revolving round the sun. The earth is one of mine planets which move in orbit round the sun. These nine planets, together with the sun, make up what is called our solar system. How this wonderful system started and what kept it working with such wonderful accuracy is largely a mystery but astronomers tell us that it is only one of millions of similar systems is space, and one of the smallest. The stars which we see glittering in the sky on a dark and cloudless night are almost certainly the suns of other solar systems more or less like our own, but they are so far away in space that it is unlikely that we shall ever get to know very much about them. About our own solar system, however, we are learning more every day. Before the American and Russian astronauts made their thrilling journeys into outer space it was difficult for us to realise what our earth looked like from hundreds of thousands of miles away, but the photographs which the astronauts were able to take show us the earth in space looking not very different from what the moon looks like when we look at it from the earth. The earth is, however, very different from the moon, which the American astronauts have found to be without life or vegetation, whereas our earth is very much alive in every respect. The moon, by the way , is called a satellite because it goes round our earth as well as round the sun. In other words, it goes round the sun with our earth. The surface of our earth is covered by masses of land and larger areas of water. Let us consider the water areas first. The total water area is about three times as large as the land area. The very large separate areas of water are called "oceans" and the lesser areas are called "seas." In most of the oceans and seas some of the water is found to be flowing in a particular direction - that is to say, from one part towards another part of the ocean or sea concerned. The water which is flowing in this manner is said to be moving as a "current." There are many thousands of currents in the waters of the oceans and seas, but only certain of the stronger and better marked currents are specially named and or great importance. These currents are important because they affect the climate of the land areas close to where they flow and also because they carry large quantities of microscopic animal and vegetable life which forms a large part of the food for fishes. The nature and characteristics of the surface of the land areas of the earth vary a great deal from area to area and from place to place. The surface of some areas consists largely of high mountains and deep valleys whilst, in other areas, most of the surface consists of plains. If one made a journey over the Continents one would find every kind of surface including mountain ranges, plains, plateaux, deserts, tropical forestlands and empty areas covered permanently by ice and snow. When thinking and learning about the world we should not forget that our world is the home of a very great many different people - peoples with different coloured skins, living very different lives and having very different ideas about a great many important things such as religion, government, education and social behaviour.  The circumstances under which different people live make a great difference between the way in which they live and the way in which we live, and it ought to be our business to try to understand those different circumstances so that we can better understand people of other lands. Above all, we should avoid deciding what we think about people different from ourselves without first having learned a great deal about them and the kind of lives they have to live. It is true to say that the more we learn about other people, the better we understand their ideas and, as a rule, the better we like those people themselves. 世界中的世界 首先让我们把地球看作是围绕太阳运行的一颗行星。地球是沿轨道围绕太阳运行的九大行星之一。这九大行星和太阳一起组成了所谓的我们的太阳系。这个奇妙的星系是怎样开始的，什么使它保持精确地运行，这是一个很大的迷。但是天文学家告诉我们太阳系只是太空里几百万个相似的星系中的一个而且是最小的一个。 在漆黑的夜空，我们看到的闪烁的星星几乎肯定是其他太阳系中有些类似我们星系中的恒星。但是它们在太空中距离我们如此遥远以至于我们不可能对其了解太多。 然而对于我们的太阳系，每天我们都会了解到更多东西。在美国和俄罗斯宇航员进行激动人心的太空旅行之前，我们很难认识到从数十万英里以外的地方看地球会是什么样子。但是宇航员们能够拍到的照 结束