英语听力：自然百科 探索世界奥秘之Alien Neighbors (寻访外星人) Unit12

How likely that technology will destroy those who invented it? The Drake Equation¹ doesn’t exactly narrow the field. Depending on the variables, the number of intelligent civilizations could be zero or a billion or any number in between. Richard Dawkins thinks the last factor in the equation might explain why the heavens are so silent.

"It’s been rather pessimistically suggested that when a civilization anywhere in the universe becomes advanced enough to, say, develop radio telescopes or the ability to communicate by radio over vast distances. That level of technology, almost inevitably², is close to...., destroying itself by atom bombs or similar weapons of mass destruction. Now if this is true, it could be an answer to the question--why haven’t we heard from other forms of life."

It’s also possible that an intelligent civilization might have more in common with our machines than ourselves.

"A really advanced civilization might have gone beyond biology to develop machine intelligence. Machine intelligence could spread throughout the galaxy³ a lot more easily than biology could. So it maybe that if we pick up a signal, it’s not from biology at all, it’s from a machine, a thinking machine."

If thinking machines populate another world, they may have evolved not from carbon molecules⁴ as we did, but from silicon⁵, the same kind of silicon that’s the basis of computer technology. Silicon is not all that different to carbon.

"Just possibly, you could imagine a kind of fantasy science fiction life which was not carbon-based but silicon-based. But you don’t have to go to silicon, you could, you could have other kinds of carbon-based organic life which would be very, very different from life on this planet as we know it and still be living. "

To stand a chance of supporting carbon-based life, there must be water. Water is essential to life as we know it. We have no evidence that life could exist on another moon or planet without water. As new moons and planets are discovered, there are bursts of hope that some life, other than life familiar to us, is out there.

1995 saw great excitement when a brand-new planet was detected. Two Swiss astronomers⁶ spotted⁷ the planet beyond our own solar system. For the first time, a planet had been found orbiting another star. Within a year of this discovery, more new planets were announced. This time, the glory belonged to two American astronomers using the Licht Telescope in San Francisco. It was this great instrument that caught the light from a distant star and showed the world that planetary systems may be common. The planet finders were Jeff Marcy and Paul Butler, and no one was as surprised about it as they were.

" When Jeff first suggested that we might find planets, it seemed like an outrageous⁸ idea, but still, it was, you know, a lot more exciting than most anything else I could imagine, so I jumped at the chance to look for planets, I didn’t know if it would ever work and it’s been a long long struggle to get here. "

words in this passage

populate：to live in an area or place 居住在…中。

eg:The settlers began to move inland and populate the river valleys.

science fiction :books, films or cartoons about an imagined future, especially about space travel or other planets科幻,科学幻想小说（亦作： sci-fi）

stand a chance of :有...的希望

see: 这里的用法与witness相同: When a place or period witnesses a particular event, the event happens in that place or during that period

eg: The past few years have witnessed momentous⁹ changes throughout Eastern Europe.

brand-new: completely new, especially not yet used:崭新的

jump at sth:to accept something eagerly:欣然接受

eg:She jumped at the chance of a trip to Paris.

1 equation   

n.方程式，等式，等同

参考例句：

• The solution can be expressed by a mathematical equation.答案可用一个数学方程式来表示。
• This equation is known as the ideal gas law.这个等式被叫做理想气体定律。

2 inevitably   

adv.不可避免地；必然发生地

参考例句：

• In the way you go on,you are inevitably coming apart.照你们这样下去，毫无疑问是会散伙的。
• Technological changes will inevitably lead to unemployment.技术变革必然会导致失业。

3 galaxy   

n.星系；银河系；一群(杰出或著名的人物)

参考例句：

• The earth is one of the planets in the Galaxy.地球是银河系中的星球之一。
• The company has a galaxy of talent.该公司拥有一批优秀的人才。

4 molecules   

分子( molecule的名词复数 )

参考例句：

• The structure of molecules can be seen under an electron microscope. 分子的结构可在电子显微镜下观察到。
• Inside the reactor the large molecules are cracked into smaller molecules. 在反应堆里，大分子裂变为小分子。

5 silicon   

n.硅(旧名矽)

参考例句：

• This company pioneered the use of silicon chip.这家公司开创了使用硅片的方法。
• A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。

6 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

7 spotted   

adj.有斑点的，斑纹的，弄污了的

参考例句：

• The milkman selected the spotted cows,from among a herd of two hundred.牛奶商从一群200头牛中选出有斑点的牛。
• Sam's shop stocks short spotted socks.山姆的商店屯积了有斑点的短袜。

8 outrageous   

adj.无理的，令人不能容忍的

参考例句：

• Her outrageous behaviour at the party offended everyone.她在聚会上的无礼行为触怒了每一个人。
• Charges for local telephone calls are particularly outrageous.本地电话资费贵得出奇。

9 momentous   

adj.重要的，重大的

参考例句：

• I am deeply honoured to be invited to this momentous occasion.能应邀出席如此重要的场合，我深感荣幸。
• The momentous news was that war had begun.重大的新闻是战争已经开始。