宇宙中有外星人吗？
课文学习台
Are There Strangers in Space?
区分观点、依据、例子与限制，用自己的话准确重建论述。
课文精读第1 / 6段
本课原文与译文
展开完整文本 · 便于查阅与检索
第1段
We must conclude from the work of those who have studied the origin of life, that given a planet only approximately like our own, life is almost certain to start. Of all the planets in our solar system, we are now pretty certain the Earth is the only one on which life can survive. Mars is too dry and poor in oxygen, Venus far too hot, and so is Mercury, and the outer planets have temperatures near absolute zero and hydrogen-dominated atmospheres. But other suns, stars as the astronomers call them, are bound to have planets like our own, and as the number of stars in the universe is so vast, this possibility becomes virtual certainty. There are one hundred thousand million stars in our own Milky Way alone, and then there are three thousand million other Milky Ways, or galaxies, in the universe.So the number of stars that we know exist is now estimated at about 300 million million million.
我们从生命起源领域的学者所做的研究中，必然会得出此结论：只要一个星球与地球相似，那么生命几乎肯定会出现。在我们太阳系的所有行星中，我们目前相当确信，地球是唯一能够维持生命的行星。 火星太干燥且缺氧，金星温度太高，水星亦然。除此之外，太阳系的其他行星的温度都接近绝对零度，且大气以氢气为主。但是，其他的太阳，即天文学家所说的恒星，肯定会有类似地球的行星。 因为宇宙中恒星的数目极其庞大，所以一定存在有生命的其它星球。单单在我们银河系就有1,000亿颗恒星，而宇宙中，银河系这样的星系还有30亿个。因此，我们已知的现有恒星数目估计为30亿与1,000亿的乘积那么多。
第2段
Although perhaps only 1 per cent of the life that has started somewhere will develop into highly complex and intelligent patterns, so vast is the number of planets, that intelligent life is bound to be a natural part of the universe.
在宇宙中已经诞生生命的地方，可能只有1%方能进化成高度复杂的智慧生命形态，可考虑到行星的巨量，智慧生命必然为宇宙中天然的一部分。
第3段
If then we are so certain that other intelligent life exists in the universe, why have we had no visitors from outer space yet? First of all, they may have come to this planet of ours thousands or millions of years ago, and found our then prevailing primitive state completely uninteresting to their own advanced knowledge. Professor Ronald Bracewell, a leading American radio astronomer, argued in Nature that such a superior civilization, on a visit to our own solar system, may have left an automatic messenger behind to await the possible awakening of an advanced civilization. Such a messenger, receiving our radio and television signals, might well re-transmit them back to its home-planet, although what impression any other civilization would thus get from us is best left unsaid.
如果我们坚信宇宙中存在着其他智慧生命，那为什么我们尚未迎来外太空的客人？ 首先，他们也许在几千年甚至几百万年前，就来过我们的地球，不过他们认为当时的地球普遍处于原始状态，和他们的先进知识相比，丝毫不感兴趣。 美国一位权威的射电天文学家罗纳德·布雷斯韦尔教授在《自然》杂志上提出了这样的观点：假如非常高级的文明生命访问了我们的太阳系，很可能会在离开太阳系时留下自动信息装置，等待先进文明可能的苏醒。该装置在接收了我们的无线电和电视信号后，很有可能会转发回母星。至于其他文明对我们地球会留下什么印象，还是不说为好。
第4段
But here we come up against the most difficult of all obstacles to contact with people on other planets—the astronomical distances which separate us. As a reasonable guess, they might, on an average, be 100 light years away. A light year is the distance which light travels at 186,000 miles per second in one year, namely 6 million million miles. Radio waves also travel at the speed of light, and assuming such an automatic messenger picked up our first broadcasts of the 1920's, the message to its home planet is barely halfway there. Similarly, our own present primitive chemical rockets, though good enough to orbit men, have no chance of transporting us to the nearest other star, four light years away, let alone distances of tens or hundreds of light years.
然而，在接触外星人的过程中，我们遇到的最大困难是分隔我们的天文距离。合理推算，外星人可能离我们平均在100光年之远 （1光年是光以每秒 186,000英里的速度在一年内所通过的距离, 即6万亿英里）。无线电波也是以光速传播的。假设外星人的这种自动信息装置接收了我们二十世纪二十年代的第一次广播信号，那么，回传母星的信息也仅仅是走了一半的路程。同样，我们目前使用的初级化学火箭，虽然能把人送入轨道，但离我们最近的星球有4光年之遥，化学火箭毫无可能送达，更不用说几十光年或几百光年之遥的星球了。
第5段
Fortunately, there is a "uniquely rational way" for us to communicate with other intelligent beings, as Walter Sullivan has put it in his excellent book, We Are not Alone. This depends on the precise radio frequency of the 21-cm wavelength, or 1,420 megahertz. It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951; it must be known to any kind of radio astronomer in the universe.
好在还是有“唯一合理的方法”可以和其他智慧生命取得联系。 正如瓦尔特·沙利文在其杰作《我们并不孤独》中所阐述的。这种联系取决于21厘米波长所对应的精确无线电频率，约1,420兆赫。这个频率是宇宙氢原子发射的自然频率，于1951年被人类发现。这个频率是宇宙中任何射电天文学家都应该知悉的。
第6段
Once the existence of this wave-length had been discovered, it was not long before its use as the uniquely recognizable broadcasting frequency for interstellar communication was suggested. Without something of this kind, searching for intelligences on other planets would be like trying to meet a friend in London without a pre-arranged rendezvous and absurdly wandering the streets in the hope of a chance encounter.
这种波长一经发现，很快就有人提出，可以把它用作星际通信中可共同识别的广播频率。没有类似的通讯方法，要想联系上其他星球的智慧生命，就好比在伦敦街头瞎逛，还希望撞见没有事先约好的朋友一样。
学完这一课
选一个可以讨论的判断，说明依据，再加上一句限制或不同情况。
译文与解析据吴应时整理资料及本站首轮审校稿；词伙与练习提示为本站学习设计。原PDF第191—196页，2022年2月第2版。