The marvelous telephone and television network that has now enmeshed the whole world, making all men neighbours, cannot be extended into space. It will never be possible to converse with anyone on another planet. Even with today’s radio equipment, the messages will take minutes—sometimes hours—on their journey, because radio and light waves travel at the same limited speed of 186, 000 miles a second.

Twenty years from now you will be able to listen to a friend on Mars, but the words you hear will have left his mouth at least three minutes earlier, and your reply will take a corresponding time to reach him. In such circumstances, an exchange of verbal messages is possible—but not a conversation.

To a culture which has come to take instantaneous communication for granted, as part of the very structure of civilized life, this “time barrier” may have a profound psychological impact. It will be a perpetual reminder of universal laws and limitations against which not all our technology can ever prevail. For it seems as certain as anything can be that no signal—still less any material object—can ever travel faster than light.

The velocity of light is the ultimate speed limit, being part of the very structure of space and time. Within the narrow confines of the solar system, it will not handicap us too severely. At the worst, these will amount to twenty hours—the time it takes a radio signal to span the orbit of Pluto, the outer-most planet.

It is when we move out beyond the confines of the solar system that we come face to face with an altogether new order of cosmic reality. Even today, many otherwise educated men—like those savages who can count to three but lump together all numbers beyond four—cannot grasp the profound distinction between solar and stellar space. The first is the space enclosing our neighbouring worlds, the planets; the second is that which embraces those distant suns, the stars, and it is literally millions of times greater. There is no such abrupt change of scale in the terrestrial affairs.

Many conservative scientists, appalled by these cosmic gulfs, have denied that they can ever be crossed. Some people never learn; those who sixty years ago scoffed at the possibility of flight, and ten years ago laughed at the idea of travel to the planets, are now quite sure that the stars will always be beyond our reach. And again they are wrong, for they have failed to grasp the great lesson of our age—that if something is possible in theory, and no fundamental scientific laws oppose its realization, then sooner or later it will be achieved.

One day we shall discover a really efficient means of propelling our space vehicles. Every technical device is always developed to its limit and the ultimate speed for spaceships is the velocity of light. They will never reach that goal, but they will get very near it. And then the nearest star will be less than five years voyaging from the earth.［514 words］

1.For light to travel across the solar system, it will take_______.

［A］ a year ［B］ nearly a day ［C］ two months ［D］ thirty minutes

2.The fact that it will never be possible to converse with someone on another planet shows that________

［A］ radio messages do not travel fast enough

［B］ no object can ever travel faster than light

［C］ western culture has a special idea of communication

［D］ certain universal laws cannot be prevailed against

3.Confronted with the new order of cosmic reality, many educated men________.

［A］ become ignorant savage again ［B］ find the “time barrier” unbearable

［C］ will not combine solar and stellar space［D］ cannot adapt to the abrupt change of scale

4.Conservative scientists who deny that cosmic gulfs can ever be crossed will________

［A］ laugh at the very idea of flight ［B］ learn a lesson as they did ten years ago

［C］ find space travel beyond their reach［D］ oppose the fundamental scientific laws

5.The author of the passage intends to show__________.

［A］ the limitations of our technology ［B］ the vastness of the cosmic reality

［C］ the prospect of planetary travel ［D］ the psychological impact of time and space

1.光穿过太阳系需要多长时间？

［A］ 一年。 ［B］ 将近一天。 ［C］ 两个月。 ［D］ 30分钟。

［精解］ 答案B本题考查考生的数字推理能力。原文中没有直接的回答，但是第一段末句指出：“无线电和光的传播速度相同。”第四段最后一句又指出，无线电传到太阳系中最远的冥王星，要20小时。所以［B］项正确。

2.人无法和另外一个星球的人进行对话这一事实表明_____。

［A］ 无线电的传播速度不够快 ［B］ 没有物体能比光的速度快

［C］ 西方文化有特别的交流观念［D］ 某些普遍规律不能被战胜

［精解］ 答案A本题考查事实细节。第一段后两句指出，“永远不可能和另一个星球人进行对话。即使有今天的无线电设备，信息传播也需要好几分钟，甚至好几个小时，因为无线电和光波都是以有限速度传播。”第二段中举了一个和火星人交流的例子，得出的结论是：“交换语言信息是可能的，但是不可能对话。”［A］项指的是传播速度的限制，为正确项。［B］是第三段末句的改写，是事实，但它与无法实现星际对话没有必然的联系。［C］项在第三段提到，但“认为即刻交流是理所当然的文化”是人思维局限的表现，而“人无法和另外一个星球的人进行对话”是自然规律事实，后者不能表明前者。该段也提到，“时间的局限性”（即无法和外星人进行对话）提醒我们不是所有的技术都能战胜普遍规律和限制，因此这里说明的是“技术的局限性”，而不是［D］项中的“规律的不可战胜性”。

3.面对宇宙现实的新秩序，许多受过教育的人士________。

［A］ 又变成无知的野人 ［B］ 发现“时间局限性”不可容忍

［C］ 将不会把太阳系和恒星系结合起来［D］ 不能适应这种突然的大规模的变化

［精解］ 答案D本题考查事实细节。文章第五段第二句提到，“许多在别的方面受过教育的人，像只能数到三的野人，无法明白太阳系和恒星系的巨大不同。……（后者比前者）确实大几百万倍，地球上的事物在规模上没有这样巨大的变化。”可见，他们无法适应如此巨大的规模变化，选择［D］。［A］项拘泥于字面含义，没有理解文中举出“野人”只是为了说明那些受过教育的人在变化面前的无知，而不是真的变成了野人。［B］项文中未提，［C］项中“结合”应换成“区分”，才符合文意。

4.否认人们可能跨越巨大宇宙鸿沟的那些保守科学家将会_______。

［A］ 嘲笑飞行的想法 ［B］ 像10年前一样吸取教训

［C］ 发现太空旅行非他们所能及［D］ 反对基本的科学规律

［精解］ 答案C本题考查事实细节。倒数第二段谈到这些保守科学家时，作者指出：“一些人从来不吸取教训；他们60年前怀疑飞行的可能性，10年前耻笑飞往其他行星的想法，现在又满有把握地说恒星是我们永远不能及的。”据此，最为相近的答案应该是［C］。

5.从课文中，我们可以推出作者的意图是要说明_______。

［A］ 我们技术的局限性 ［B］ 宇宙现实的广阔性

［C］ 星际旅行的前景 ［D］ 时间和空间对心理上的影响

［精解］ 答案C本题考查写作目的。综观全文，作者从无线电和光速谈起，批评了很多持保守态度的人，进而论证人类终将跨越宇宙鸿沟。文章最后描述未来星际旅行标志了人类跨越宇宙鸿沟的实现。可见，［C］是作者要说明的问题。