新概念英語第四冊
Lesson 43 Are there strangers in space
1 . have no chance of transporting us to the nearest other star, four light years away,但尚不可能把我們送到離我們最近、相距4光年的其他星球上去，
2 . may have left an automatic messenger behind to await the possible awakening of an advanced civilization.很可能會在離開太陽系時留下自動化信息裝置，等待先進文明的覺醒。
3 . First of all, they may have come to this planet of ours thousands or millions of years ago,首先，他們可能在幾千年前或幾百年萬年前已來過我們地球，
4 . Without something of this kind, searching for intelligences on other planets沒有這種手段，要想尋覓其他星球上的智力生命，
5 . as Walter Sullivan has put it in his excellent book, We Are not Alone.正如沃爾特·沙利文在其傑作《我們並不孤獨》中闡述的。
6 . As a reasonable guess, they might, on an average, be 100 light years away.據合理推算，外星人離我們平均距離也有100光年之遠
7 . But other suns, stars as the astronomers call them, are bound to have planets like our own,但是，其他的太陽，即天文學家所說的恆星，肯定會有像我們地球一樣的行星。
8 . although what impression any other civilization would thus get from us is best left unsaid.至於其他文明行星對我們地球會有什麼印象，還是不說為好。
9 . Once the existence of this wave-length had been discovered,一旦這種波長的實際存在被發現，
10 . (A light year is the distance which light travels at 186,000 miles per second in one year,一光年是光以每秒186，000英里的速度在一年內走的距離，
11 . It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951;這個頻率是空間氫原子釋放的自然頻率，是在1951年被人類發現的。
12 . and assuming such an automatic messenger picked up our first broadcasts of the 1920's,假定外星人的這種自動化信息裝置接收到了我們二十世紀二十年代的第一次廣播信號，
13 . Of all the planets in our own solar system,在我們太陽系的所有行星中，
14 . So the number of stars that we know exist is now estimated at about 300 million million million.因此，我們所知道的現有恆星數目估計約有30億×1000億顆。
15 . it was not long before its use as the uniquely recognizable broadcasting frequency for interstellar communication was suggested.提出把它作為星際間唯一可辨認的廣播頻率就為期不遠了。
16 . Fortunately, there is a 'uniquely rational way' for us to communicate with other intelligent beings,幸運的是，有一種我們可以和其他智力生命通迅聯繫的"唯一合理的方法"，
17 . There are one hundred thousand million stars in our own Milky Way alone,僅我們的銀河系就有1000億顆恆星，
18 . the message to its home planet is barely halfway there.那麼這個信號在發回到原來的行星途中剛剛走了一半路程。
19 . Similarly, our own present primitive chemical rockets, though good enough to orbit men,同樣，我們目前使用的原始化學火箭，雖然可以把人送入軌道，
20 . 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.就如同去倫敦見一位朋友，事先未約定地點，而荒唐地在街上遊逛，以期待碰巧遇上一樣。
21 . might well re-transmit them back to its home-planet,完全有可能把這些信號發回到原來的行星。
22 . This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second.這種通訊聯繫要靠21厘米波段，即每秒1420兆周的精確無線電頻率。
23 . 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.然而，在和外星人聯繫中我們遇到的最大困難是分隔我們的天文距離。
24 . Professor Ronald Bracewell, a leading American radio astronomer,argued in Nature that such a superior civilization, on a visit to our own solar system,假如有如此高級文明生命訪問了我們的太陽系，
25 . Mars is too dry and poor in oxygen, Venus far too hot, and so is Mercury,火星太乾燥又缺氧，金星太熱，水星也一樣。
26 . that given a planet only approximately like our own, life is almost certain to start.如果設想有一顆行星和我們地球的情況基本相似，那幾乎肯定會產生生命。
27 . and found our then prevailing primitive state completely uninteresting to their own advanced knowledge.並且發現我們地球當時普遍存在著的原始狀態同他們先進的知識相比是索然無味的。
28 . namely 6 million million miles.) Radio waves also travel at the speed of light,即6萬億英里）。無線電波也是以光速傳播的。
29 . it must be known to any kind of radio astronomer in the universe.這個頻率是宇宙中任何射電天文學家都應該熟悉的。
30 . If then we are so certain that other intelligent life exists in the universe,既然我們如此堅信宇宙中存在著其他有智力的生命，
31 . and as the number of stars in the universe is so vast,因為宇宙中恆星的數目極其龐大，
32 . this possibility becomes virtual certainty.所以存在著產生生命星球的這種可能性是肯定無疑的。
33 . that intelligent life is bound to be a natural part of the universe.有智力的生命必然是宇宙的自然組成部分。
34 . we are now pretty certain the Earth is the only one on which life can survive.我們目前可以肯定的是，地球是生命能存在的唯一行星。
35 . Such a messenger, receiving our radio and television signals,這種自動化信息裝置，在接收到我們的無線電和電視信號後，
36 . and the outer planets have temperatures near absolute zero and hydrogen-dominated atmospheres.除此以外，太陽系的其他行星的溫度都接近絕對零度，並圍繞著以氫氣為主的大氣層。
37 . We must conclude from the work of those who have studied the origin of life,我們必須從那些研究生命起源的人的工作總結出：
38 . and then there are three thousand million other Milky Ways, or galaxies, in the universe.況且在宇宙中還有30億個天河，即銀河系。
39 . let alone distances of tens or hundreds of light years.更不用說幾十光年或幾百光年遠的地方了。
40 . so vast is the number of planets,但是行星的數目是那麼龐大，
41 . why have we had no visitors from outer space yet?那麼我們為什麼還未見到外層空間來訪的客人呢？
42 . Although perhaps only 1 per cent of the life that has started somewhere will develop into highly complex and intelligent patterns,雖然在已經產生生命的某個地方，可能只有1%會發展成高度複雜有智力的生命形態，