新概念第四册课文[新概念第四册课文翻译及学习笔记【Lesson43、44、45】]

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新概念第四册课文[新概念第四册课文翻译及学习笔记

【Lesson43、44、45】]

【导语】新概念英语作为一套世界闻名的英语教程，以其全新的教学理念，有趣的课文内容和全面的技能训练，深受广大英语学习者的欢迎和喜爱。为了方便同学们的学习，大为大家了最全面的新概念第四册课文翻译及学习笔记，希望为大家的新概念英语学习提供帮助!

First listen and then answer the following question.

What does the \with other intelligent beings in space depend on?

We must conclude from the work of those who have studied the origin of life, that given a pla only approximately like our own, life is almost certain to start. Of all the plas in our solar system, we ware 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 plas have temperatures near absolute zero and

hydrogen-dominated atmospheres. But other suns, start as the astronomers call them, are bound to have plas like our own, and

as is the number of stars in the universe is so vast, this possibility bees virtual certainty. There are one hundred thousand million starts 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 the stars that we know exist is now estimated at about 300 million million million.

Although perhaps only 1 per cent of the life that has started somewhere will develop into highly plex and intelligent patterns, so vast is the number of plas, that intelligent life is bound to be a natural part of the universe.

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 e to this pla of ours thousands or millions of years ago, and found our then prevailing primitive state pletely 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-pla, although what impression any other civilization would thus get from us is best left unsaid.

But here we e up against the most difficult of all obstacles to contact with people on other plas -- 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\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.

Fortunately, there is a \rational way\for us to municate 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 1420 megacycles per second. 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.

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 munication was suggested. Without something of this kind, searching for intelligences on other plas 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.

ANTHONY MICHAELIS Are There Strangers in Space? from The Weekend Telegraph

Mercury n. 水星

hydrogen n. 氢气

prevailing adj. 普遍的

radio astronomer 射电天方学家

uniquely adv. 唯一地

rational adj. 合理的

radio frequency 无线电频率

cm n. 厘米

megacycle n. 兆周

emission n. 散发

intersteller adj.星际的