目 录 上一节 下一节 
卫星通讯 At the beginning of the twentieth century, there were four powerful means of transmitting and receiving information over long distances: print, photography, telegraph and telephone. By the middle of the century, both radio and television had become established means of transmitting sounds and/or pictures. In 1962, the Olympic Games in Tokyo became the first program to be transmitted via satellite. 在20世界初，远距离发出和接收信息的有效手段有四种：印刷、照像、电报和电话。到了本世纪中期，无线电和电视成了传送音响和图像的主要手段。1964年东京奥运会首次通过卫星传送节目。 In order to transmit an event such as the Olympics via satellite, television signals are first changed into radio waves, which are then sent from a station on earth to an orbiting satellite. The satellite receives the radio waves and sends them back to earth, where another station picks them up and changes them back into television signals. Because any from of sound or visual information can be changed into radio waves, satellite are capable of transmitting not only television broadcasts, but telephone calls and printed materials such as books and magazines. 要通过卫生把诸如奥运会之类的情况传输出去，首先得把电视信号转化成无线电波，然后再把无线电波从地球上的发射台传送到在轨道上与地球同步运行的卫星。这颗卫星收到无线电波以后再把无线电波传回到地球上。地球的另外一个接收台收到无线电波以后再把无线电波还原成电视信号。因为任何一种形式的音响或图像信息都可以转换成无线电波，所以卫星不但能传输电视广告也能传输电话以及书刊杂志之类的印刷材料。 The combination of satellites, which transmit information, computers, which store information, and television, which displays information, will change every home into an education and entertainment center. In theory, every person will have access to an unlimited amount of information. 卫星可以传输信息，电脑可以储存信息，电视可以显示信息，把这三者结合起来就可以把家家户户都变成教育中心和娱乐中心。从理论上讲，每个人都可以接收到没有任何数量限制的信息。 Another important use of telecommunication satellites was demonstrated in 1974 when the "Teacher in Sky" satellite transmitted educational programs to classes in remote areas of the United States. In 1975, many people in India saw television for the first time as they watched programs about agriculture and health. 在1974年，"空中教师"卫星把教学节目传送到了美国边远地区的课堂上，这就展现出来了通讯卫星的又一个重要的用途。1975年，在印度有很多人初次在电视上观看了有关农业和卫生保健方面的节目。 
卫星展现出另一种用途，即帮助那些生活在交通困难又很闭塞地区的人们。例如：在闭塞地区的一位卫生工作人员可以把一个患者的伤病的图像传送给远方的医生，这个卫生工作人员就可以按着医生的指标来护理伤病员。 The most common use of telecommunication satellites, however, has been for transmitting telephone calls. Most of them travel 40,000 miles to a satellite and then back to earth. Ten years ago, a satellite was capable of receiving and transmitting more than 33,000 telephone conversations simultaneously. Now a single satellite is able to transmit over 100,000 conversations as well as several hundred television channels - all at the same time. 然而，通讯卫星最普遍的是用来传送电话。绝大部分电话要发射给四万英里远的高空卫星然后再传回到地球。10年前，一颗卫星只能在同一时间内接收到并传送出三万三千次电话上的谈话。现在仅仅一颗卫星在同一时间内不但可以传送十万次电话还可以同时传送十来个电视频道的节目。 Telecommunication can make information from around the world available to use quickly and easily, but some people worry that this may be a risk to our privacy. If personal information is stored in computers, then it may be easily transmitted via satellite to anyone who can pay for the service. 远程通讯可以使来自世界各地的信息方便快捷地供人们使用。但是，这也使有些人担心会使我们的个人隐私权受到威胁。如果我们把个人的一切信息资料都储存到电脑里，那么任何一个人，只要支付了一定费用，就很容易地通过卫星把我们的个人信息资料传送给那个人。 Another worry is that telecommunication systems may isolate people from each other. When people are able to shop from their homes, do their banking without leaving the house, watch may movie they want on their television, as well as get any information they need, then there will not be as much contract between people. 另一种让人担心的事情就是这些通讯系统很可能会把人和人给隔绝开了。如果将来人们不但在自己家里就可购物，不离开家就能办理银行的业务、就能在电视上看到人们想看的电影，还能得到人们想要的任何信息资料，到那时，人与人之间的接触的机会，就不会像现在影视样多了。 It is important to realize that the same technology that helps us may also harm us. We can prevent this from happening by carefully controlling the new technology. As one telecommunication expert says, "we must remember that technology alone is not the answer …It is the intelligent application of technology that will lead us to success."有一点是很重要的，好就是要让人们意识到，同一项技术既可能会帮助我们，也可能会伤害我们。我们可以用仔细认真地控制某项新技术的办法来防止该项技术会对我们造成的伤害。正像一位通讯专家所说的那样："技术本身并不是我们要追寻的答案。正是明智地运用技术才会引导我们走向成功的目标。" 
关于空气、天空、大气层人们还不大了解的一些现象 The air around us is important to everyone. Without air, we could not exist. Everyone understands that. But air is necessary in many other ways - ways that are not always so obvious or widely known. 我们周围的空气对每个人都是重要的。倘若没有空气，我们也就不能存在了。这是每个人都懂的。在其他情况下，也都必须有空气，这些其他情况并不都是显示而易见或广为人知的。 For example, if we did not have air, there would be no sound. Sound travels through air. Where there is no air, there is no sound. Without air, there would be no fire. There would be no cars or trucks, since motors need air in order to work. 举个例子，如果我们现在没有空气，就不会有声音。声音是通过空气来传播的。凡是没有空气的地方，就没有声音。倘若没有空气，也不会有火，也不会有小汽车和大卡车，因为这些机动车要运转就需要空气。 Without air, there would be no wind or clouds. There would be no weather, as we know it. The night time would be very cold and the days very hot. We would be forced to seek shelter from the sun, as there would be no atmosphere to protect us from the sun's deadly rays. 倘若没有空气，就不会有风或云，也不会有天气变化，这是众所周知的。倘若没有空气，夜间就会很冷，白天又会很热。因为若是没有了大气层来保护我们，我们就会不得不去找一个藏身的地方，来躲避好些致人死命的太阳光线。 The atmosphere is all the air surrounding the earth. Atmospheric pressure is the weight of all that air against the surface of the earth. If we did not have atmospheric pressure, we could not have automobile tires. The tires would burst if they did not have the pressure of the atmosphere against their surfaces. 大气层就是包围了地球的所有空气。大气压就是压在地球表面上的所有的空气的重量。假如我们没有大气压，我们就不能有汽车轮胎了。如果我们现在没有了大气压来顶住或压住那些汽车轮胎的表面，那么那些轮胎就会爆裂了。 
大气层占据极大的空间，具有极强的压力，它由高达数百英里的厚厚的一层空气所组成的。大气压压到我们身上的重要在每平方英时上达14英磅以上。我们的双肩上所承受的细长的空气柱的重要几乎有2000英磅重。不过我们的身体构造都是很坚固的，以致大气压的重要是不可能把我们压垮的。 In this huge ocean of air there is more energy than in all the coal, oil, and gas we have on earth. Electrical energy is collected in the atmosphere as water is collected and stored in a dam. The existence of electricity in the air has been known for centuries. Men have gazed in wonder at the bright patterns of lightning in storm clouds. But a through study of electricity in the atmosphere was not possible until the development of radio and radar. 在这巨大的广阔无垠的空气层中存在着的电能，比在地球上的煤、石油、天然气加起来所能产生的电能还要多。电能被集存在大气层中，正像水被汇集到一起，然后储存在水库里是一样的。在大气层中电是存在的，这一事实多少世纪以前人们就已经知道了。人们以惊奇而又不解的眼神凝视着暴风雨云中闪现出来的耀眼的闪电的种种形态。但是彻底地研究和仔细观察大气层中的带电现象，只有在研制出了无线电和雷达之后才有可能。 One scientist, Dr. Sydney Chapman, has tried to explain the electric field which surrounds the earth. He believes that the great storms on the sun create large amounts of electric energy. This energy is contained in a very light gas called hydrogen. The earth pulls the gas toward it, and a ring is formed around the earth several thousand feet above its surface. The great space ring is a powerful current of electrical energy. Sometimes the ring comes down and curves into the lower atmosphere, causing strange electrical effects. 有位科学家，悉得尼查普曼博士，试图解释包围了地球的电磁场。他认为太阳上的巨大的磁暴产生了大量的电能。这种电能里有一种很轻的气体，称为"氢"。地球把这种气体吸引到地球的周围，于是地球表面的上空中就形成一个把地球包围起来起来的几千英尺厚的由氢所形成的园形外壳。这个巨大的外壳里就有着强大电流的电能。有时这个园形的氢外壳会下降会弯进了较低的大气层里，这就引起了一些奇异的电效应。 Dr. Chapman's ideas explain many things. It has long been known that there is an electric field inside the earth. It moves in much the same manner as the electric energy contained in the atmosphere. Scientists now believe that the electric energy in the atmosphere causes the electric energy inside the earth to flow. 查普曼博士的理论解释了很多现象。地球内部有一个磁场，这是人们早就知道的。地球内部的电磁场的流动方式正像大气层中的电能的流动方式是一样的。现在科学家们认为大气层中的电能引起了地球内部的电能流动。 If we can learn to control the energy in the atmosphere, we will have an unending supply of energy. Many scientists are trying to learn how to control it. In the meantime, even those of us who are not scientists have begun to pay attention to air. We realize that air does not contain the same elements that it contained years ago. Automobiles, airplanes, factories, and atomic explosions have added dust and waste gases to the atmosphere. It is time to learn how to protect our atmosphere, the roof over the world of man. 如果我们将来能够学会控制大气层中的能源，那我们将来就会有取之不尽用之不竭的能源了。许多科学家正在试图学会控制大气层的能源。与此同时，甚至像我们这些根本就不是科学家的人，也已经开始注意到空气、天空、大气层了。我们意识到了空气中所含的成分跟若干年以前不一样了。各种类型的汽车，形形色色的飞机，大大小小的工厂，一次一次的原子弹爆炸，都把烟尘和种种废气排到大气层中。该是我们人类学会保护大气层，也就是学会保护我们人类世界的大层顶棚的时候了。
| 
