Lesson 43 Are there strangers in space

and as the number of stars in the universe is so vast,

因?yàn)橛钪嬷泻阈堑臄?shù)目極其龐大，

Lesson 43 Are there strangers in space

this possibility becomes virtual certainty.

所以存在著產(chǎn)生生命星球的這種可能性是肯定無疑的。

Lesson 43 Are there strangers in space

There are one hundred thousand million stars in our own Milky Way alone,

僅我們的銀河系就有1000億顆恒星，

Lesson 43 Are there strangers in space

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(gè)天河，即銀河系。

Lesson 43 Are there strangers in space

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(xiàn)有恒星數(shù)目估計(jì)約有30億×1000億顆。

Lesson 43 Are there strangers in space

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(jīng)產(chǎn)生生命的某個(gè)地方，可能只有1%會(huì)發(fā)展成高度復(fù)雜有智力的生命形態(tài)，

Lesson 43 Are there strangers in space

so vast is the number of planets,

但是行星的數(shù)目是那么龐大，

Lesson 43 Are there strangers in space

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。

Lesson 43 Are there strangers in space

If then we are so certain that other intelligent life exists in the universe,

既然我們?nèi)绱藞?jiān)信宇宙中存在著其他有智力的生命，

Lesson 43 Are there strangers in space

why have we had no visitors from outer space yet?

那么我們?yōu)槭裁催€未見到外層空間來訪的客人呢？

Lesson 43 Are there strangers in space

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，

Lesson 43 Are there strangers in space

and found our then prevailing primitive state completely uninteresting to their own advanced knowledge.

并且發(fā)現(xiàn)我們地球當(dāng)時(shí)普遍存在著的原始狀態(tài)同他們先進(jìn)的知識(shí)相比是索然無味的。

Lesson 43 Are there strangers in space

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(jí)文明生命訪問了我們的太陽系，

Lesson 43 Are there strangers in space

may have left an automatic messenger behind to await the possible awakening of an advanced civilization.

很可能會(huì)在離開太陽系時(shí)留下自動(dòng)化信息裝置，等待先進(jìn)文明的覺醒。

Lesson 43 Are there strangers in space

Such a messenger, receiving our radio and television signals,

這種自動(dòng)化信息裝置，在接收到我們的無線電和電視信號(hào)后，

Lesson 43 Are there strangers in space

might well re-transmit them back to its home-planet,

完全有可能把這些信號(hào)發(fā)回到原來的行星。

Lesson 43 Are there strangers in space

although what impression any other civilization would thus get from us is best left unsaid.

至于其他文明行星對(duì)我們地球會(huì)有什么印象，還是不說為好。

Lesson 43 Are there strangers in space

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(lián)系中我們遇到的最大困難是分隔我們的天文距離。

Lesson 43 Are there strangers in space

As a reasonable guess, they might, on an average, be 100 light years away.

據(jù)合理推算，外星人離我們平均距離也有100光年之遠(yuǎn)

Lesson 43 Are there strangers in space

(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(nèi)走的距離，

Lesson 43 Are there strangers in space

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。

Lesson 43 Are there strangers in space

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(dòng)化信息裝置接收到了我們二十世紀(jì)二十年代的第一次廣播信號(hào)，

Lesson 43 Are there strangers in space

the message to its home planet is barely halfway there.

那么這個(gè)信號(hào)在發(fā)回到原來的行星途中剛剛走了一半路程。

Lesson 43 Are there strangers in space

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(xué)火箭，雖然可以把人送入軌道，

Lesson 43 Are there strangers in space

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，

Lesson 43 Are there strangers in space

let alone distances of tens or hundreds of light years.

更不用說幾十光年或幾百光年遠(yuǎn)的地方了。

Lesson 43 Are there strangers in space

Fortunately, there is a 'uniquely rational way' for us to communicate with other intelligent beings,

幸運(yùn)的是，有一種我們可以和其他智力生命通迅聯(lián)系的"唯一合理的方法"，

Lesson 43 Are there strangers in space

as Walter Sullivan has put it in his excellent book, We Are not Alone.

正如沃爾特·沙利文在其杰作《我們并不孤獨(dú)》中闡述的。

Lesson 43 Are there strangers in space

This depends on the precise radio frequency of the 21-cm wavelength, or 1420 megacycles per second.

這種通訊聯(lián)系要靠21厘米波段，即每秒1420兆周的精確無線電頻率。

Lesson 43 Are there strangers in space

It is the natural frequency of emission of the hydrogen atoms in space and was discovered by us in 1951;

這個(gè)頻率是空間氫原子釋放的自然頻率，是在1951年被人類發(fā)現(xiàn)的。