First listen and then answer the following question.
听录音，然后回答以下问题。
What does the ‘uniquely rational way’ for us to communicate 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 planet only approximately like our own, life is almost certain to start. Of all the planets in our own 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.
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.
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.
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.
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 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 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.
ANTHONY MICHAELIS Are There Strangers in Space? from The Weekend Telegraph
New words and expressions生词和短语
Mercury(1.4)/'m*:kjuri/n.水星
cm(1.31)(=centimetre/'senti?mi:t+/)n. 厘米
hydrogen(11.4-5)/'haidr+dN+n/n.氢气
megacycle(1.31)/'meg+?saik+l/n.兆周
prevailing(1.15)/pri'veiliR/adj.普遍的
emission(1.31)/I'miM+m/n.散发
radio astronomer(1.16)/'reidi+u+'str%n+m+/射电天文学家
intersteller(1.35)/?int+'stel+/adj. 星际的
rendezvous(1.37)/'r%ndivu:/n. 约会地点
uniquely (1.29)/ju:'ni:kli/adv.唯一地
encounter(1.37)/in'kaunt+/n.相遇
rational(1.29)/'r$M+n+l/adj.合理的
radio frequency(11.30-31)/'reidi+(>fri:kw+nsi/无线电频率
Notes on the text课文注释
1 that given a planet…certain to start, 这是一个宾语从句，作动词conclude的宾语，其中given a planet…our own，过去分词短语作条件状语，given与 if的意思相近，这个过去分词短语可译成“如果一个行星与我们所在的行星大致相同的话”。
Refer to the text to see how the following words have been used, then write sentences of your own using these words: approximately (1.2);prevailing primitive state(1.15);automatic messenger(1.17);obstacles(1.21);orbit(1.26); interstellar(1.35); chance encounter(1.37).
Summary摘要
Drawing your information from lines 21-37 (‘But here ... chance encounter.’), write an account of the difficulties of interstellar communication. Do not write more than 100 words. Use your own words as far as possible. Your answer should be in one paragraph.
Composition作文
Write a composition of about 600 words on one of the following subjects:
1 The universe.
2 Flying saucers.
3 If an outside observer were given the opportunity to spend a year on earth, what impression might he get of its inhabitants?
Key structures 关键句型
A Note the form of the verb in italics:
But other suns are bound to have planets like our own. (11.5-6)
Write sentences using the following expressions:
sure to; about to; due to.
B Rewrite the sentences given below using the opening phrases provided. Do not refer to the passage until you have finished the exercise:
1 As the number of planets is so vast, intelligent life is bound to be a natural part of the universe.
So vast ______ (1.11)
2 First of all, it is possible that they came to this planet of ours thousands or millions of years ago.
First of all, they may _______(1.14)
3 It was argued in Nature by Professor Ronald Bracewell, a leading American radio astronomer, that such a superior civilization, on a visit to our own solar system, may have left an automatic messenger behind.
Professor Ronald Bracewell, _____ (11.16-17)
4 Even if our own present primitive chemical rockets are good enough to orbit men, they have no chance of transporting us to the nearest other star.
Our own present ... though ______ (11.26-27)
Special difficulties难点
A Study the following pairs of words and then write sentences of your own to bring out the difference.
1 planet (1.2) ---- star (1.6)
Live images of the robotic vehicle, Sojourner, have been relayed from the planet Mars to our T.V. screens in seconds.
There must be other stars, like our own sun, with orbiting planets similar to Earth.
2 estimated (1.9) ---- esteemed
The cost of repair has been estimated at $45.
German mechanical engineering is highly esteemed world-wide.
3 natural (1.11) ---- physical
It's quite natural for a boy's voice to break when he is about 14.
Boxers take a lot of physical punishment.
4 unsaid (1.20) ---- untold
Some things are better left unsaid.
The floods have caused untold misery to hundreds of thousands of farmers this year.
5 search for (1.36) ---- search
The whole village has been searching for the missing boy.
The security guards are searching each passenger.
B Note the use of let alone in this sentence:
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. (11.26-28)
Complete the following sentences:
1 He's incapable of adding up a simple list of figures, let alone ______
2 He doesn't earn enough to support himself, let alone_____
Multiple choice questions 多项选择题
Choose the correct answers to the following questions.
Comprehension 理解
1 The possibility that life exists on other planets is almost certain because ______ .
a．there are plenty of planets like our own
b．the other planets in our solar system are unlikely to support life
c．our own galaxy is so large
d．of the sheer number of planets in the universe
2 According to the writer, ____.
a．there is a possibility that we constantly have visitors from outer space
b．our planet may have been visited at some time during the distant past
c．an automatic messenger was left on our planet at some time in the past
d．our civilization is just awakening and is of interest to other beings
3 Travel in the universe is difficult because ____.
a．even at the speed of light, distances are immense
b．light travels at 186,000 miles per hour
c．planets are 100 light years away
d．there are no rockets in the universe powerful enough
4 The discovery of the natural frequency of emission of hydrogen atoms in space is important because ________.
a．it's a precise radio frequency of 1420 megacycles per second
b．it would be universally recognized by intelligent life anywhere in the universe
c．it makes the discovery of intelligent life elsewhere virtually certain
d．hydrogen is abundant exclusively in our own solar system
Structure 句型
5 Life ______ present on a planet approximately like our own. (11.1-2)
a．was
b．might be
c．must be
d．is
6 Why have we had no visitors from outer space_____ ? (11.13-14)
a．before
b．in the past
c．so far
d．till then
7 They were not ______our primitive state. (1.15)
a．interesting to (6) interesting in
c．interested to
d．interested in
8 We have no chance ______by our own primitive chemical rockets. (11.26-27)
a．to be transporting
b．to transport
c．of transporting
d．of being transported
Vocabulary词汇
9 They are_____ to have planets like our own.(11.5-6)
a．almost certain
b．obliged
c．required
d．due
10 What impression they would get of us is best left _____.(11.19-20)
a．unspoken
b．untold
c．unmentioned
d．unrecounted
11 We come up against the most difficult of all obstacles to ____people.(1.21)
a．speaking to
b．being in touch with
c．touching
d．reaching out to
12 This depends on the _____radio frequency of the 21cm wavelength. (11.30-31)
