国家地理-2008-04-19 New Search For ET 寻找外星人（下）

Is anyone out there? For over 40 years scientists have been searching for extraterrestrial intelligence, but they’ve found nothing. Now the new Allen Telescope Array, a string of 350 radio telescopes, is being built 300 miles north of San Francisco and is breathing new life into the search. Find out why SETI scientists now say we might be hearing from ET sooner than you think.

 Senior SETI astronomer¹ Seth Shostak tells us how this new telescope will work.

“And clearly, we are trying to find evidence of ET, and we are trying to do that by looking for a signal, in what’s called the electromagnetic spectrum², which is a fancy way of saying the radio dial, at least for us. Let me turn on my radio here, okay, now you hear that static, all right. That's just all natural noise. Galaxies³ and hot gas between the galaxies, and pulsars and quasars, they all make radio noise. And it’s everywhere on the dial. But if I tune⁴ more far over here, get that squeal⁵ and then, right there, intelligent life, okay. And that’s the difference between nature and some deliberate signal, because it’s at one spot on the dial. Nature does not make signals that are restricted to one spot on the dial in general. It just doesn’t do that. ”
 
Since the cosmos⁶ just don’t make Nero focus signals like this, finding one would be an almost certain sign of an alien culture. So what is it about this new array that makes it more likely to succeed? ''The Allen Telescope Array, basically, is all about speed. We can look at more than one star at once. And so whereas in the last decade, we looked at about a thousand stars, in the next decade, we’ll look at a million.''
 
That’s because the Allen Array's field of view, the area of sky it sees at one time is much larger than any other telescope. And it can capture millions of frequencies from multiple star systems simultaneously⁷. Basically, the Allen Telescope Array is a SETI hot rod with SETI astronomers⁸ at the controls 24/7.
 
“So, if you look inside here, you kind of see where the robot meets the rod in terms of these antennas⁹. I mean, the operation is actually in principle very very simple. The radio waves come in from the sky and then they come down to this Buck¹⁰ Rogers-looking thing here. This is called the feed. But really all it does is to take sorts of incoming radio waves and amplifies¹¹ them and turns them into electrical signals, the things go down to a fiber¹² rob cable back underground to the control room. Now, this thing looks so funny, because it’s got to be able to pick up radio waves at various wavelengths¹³ from the, you know, from relatively¹⁴ long to relatively short. So that’s why it has this taper-looking backgear here for the longer wavelengths and front-line for the shorter.”
 
“The antennas send everything they collect from the cosmos into this room, there comes in like I hear. If you think of what Frank did in 1960, he had one channel of radio noise, he was modeling one; here we’ve got a hundred million channels coming in and then we move up the dial to take in another hundred million and another hundred million.''
 
The sheer scale of the search is almost impossible to imagine. Remember, in our galaxy¹⁵ alone, there are over three hundred billion other suns, many with orbiting planets. And beyond that, lie a hundred billion other galaxies, just like our own. Even in its current configuration¹⁶, the arrays virtual dish gathers nine times more information than present-day processor technology can decode¹⁷. That means, ninety percent of what the telescope observes is simply thrown away. So for the next decade or two, the technology in this little room will be playing catch-up with the dishes outside.

 “We know that technology is gonna continue to advance in an exponential rate, and so all this stuff will be replaced in another five years by yet faster machines which allow us to look at more star systems, more channels, in other words, to speed up the SETI search.”
 
And as that search accelerates, Tarter¹⁸ and other SETI scientists are thinking about the consequences of success.
 
“If we detect a signal, we’ll do everything that we can at the sight to make sure that it isn’t our own technology that’s fooling us, or that it isn’t a deliberate hoax¹⁹. If we get an independent confirmation²⁰, then, we will in fact tell the world, because a signal isn’t being sent to the Allen Telescope Array, it’s being sent to the planet earth, and the planet earth deserves to know about it.”
 
But once the world has been notified, then what? Let’s just say, an official response plan, probably won’t be necessary. “If you ever announce that you’ve detected a signal, and give the description of what it is and where it’s coming from. Anybody with a transmitter is gonna get on the horn and shout whatever they want. And wouldn’t that be just about the best characterization of 21st century earth in an unorganized cacophony²¹?” That’s exactly the kind of thing SETI scientists are seeking. Even the accidental noise of an alien culture would answer one of the most ancient questions of all--Are we alone?
 
''Humans have been asking it forever. The probability of success is difficult to estimate, but if we never search, the chance of success is zero.''
 
pulsar: 脉冲星
rotating neutron²² stars that are observable as sources of electromagnetic radiation.
 
quasar：类星体
an astronomical²³ object that looks like a star in optical telescopes (i.e. it is a point source), and has a very high redshift.
 
exponential：
exponential growth, increase etc becomes faster as the amount of the thing that is growing increases

 cacophony：
sound that is harsh and unpleasant-sounding.

1 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

2 spectrum   

n.谱，光谱，频谱；范围，幅度，系列

参考例句：

• This is a kind of atomic spectrum.这是一种原子光谱。
• We have known much of the constitution of the solar spectrum.关于太阳光谱的构成，我们已了解不少。

3 galaxies   

星系( galaxy的名词复数 )； 银河系； 一群（杰出或著名的人物）

参考例句：

• Quasars are the highly energetic cores of distant galaxies. 类星体是遥远星系的极为活跃的核心体。
• We still don't know how many galaxies there are in the universe. 我们还不知道宇宙中有多少个星系。

4 tune   

n.调子；和谐，协调；v.调音，调节，调整

参考例句：

• He'd written a tune,and played it to us on the piano.他写了一段曲子，并在钢琴上弹给我们听。
• The boy beat out a tune on a tin can.那男孩在易拉罐上敲出一首曲子。

5 squeal   

v.发出长而尖的声音；n.长而尖的声音

参考例句：

• The children gave a squeal of fright.孩子们发出惊吓的尖叫声。
• There was a squeal of brakes as the car suddenly stopped.小汽车突然停下来时，车闸发出尖叫声。

6 cosmos   

n.宇宙；秩序，和谐

参考例句：

• Our world is but a small part of the cosmos.我们的世界仅仅是宇宙的一小部分而已。
• Is there any other intelligent life elsewhere in the cosmos?在宇宙的其他星球上还存在别的有智慧的生物吗？

7 simultaneously   

adv.同时发生地，同时进行地

参考例句：

• The radar beam can track a number of targets almost simultaneously.雷达波几乎可以同时追着多个目标。
• The Windows allow a computer user to execute multiple programs simultaneously.Windows允许计算机用户同时运行多个程序。

8 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》

9 antennas   

[生] 触角，触须（antenna的复数形式）

参考例句：

• Marconi tied several antennas to kites. 马可尼在风筝上系了几根天线。 来自超越目标英语 第3册
• Radio astronomy today is armed with the largest antennas in the world. 射电天文学拥有世界上最大的天线。

10 buck   

n.雄鹿，雄兔；v.马离地跳跃

参考例句：

• The boy bent curiously to the skeleton of the buck.这个男孩好奇地弯下身去看鹿的骸骨。
• The female deer attracts the buck with high-pitched sounds.雌鹿以尖声吸引雄鹿。

11 amplifies   

放大，扩大( amplify的第三人称单数 )； 增强； 详述

参考例句：

• Gain is the number of times the amplifier amplifies a signal. 增益就是放大器放大信号的倍数。
• Such panicky behaviour amplifies the impact of the Russian export ban. 这样的恐慌行为放大了俄罗斯小麦出口禁令的影响效应。

12 fiber   

n.纤维，纤维质

参考例句：

• The basic structural unit of yarn is the fiber.纤维是纱的基本结构单元。
• The material must be free of fiber clumps.这种材料必须无纤维块。

13 wavelengths   

n.波长( wavelength的名词复数 )；具有相同的/不同的思路；合拍；不合拍

参考例句：

• I find him difficult to talk to—we're on completely different wavelengths. 我没法和他谈话，因为我们俩完全不对路。 来自《简明英汉词典》
• Sunlight consists of different wavelengths of radiation. 阳光由几种不同波长的射线组成。 来自辞典例句

14 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

15 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。

16 configuration   

n.结构，布局，形态，(计算机)配置

参考例句：

• Geographers study the configuration of the mountains.地理学家研究山脉的地形轮廓。
• Prices range from $119 to $199,depending on the particular configuration.价格因具体配置而异，从119美元至199美元不等。

17 decode   

vt.译（码），解（码）

参考例句：

• All he had to do was decode it and pass it over.他需要做的就是将它破译然后转给他人。
• The secret documents were intercepted and decoded.机密文件遭截获并被破译。

18 tarter   

tart（酸的，辛辣的）的比较级形式

参考例句：

• Bruce Tarter, who has directed Lawrence Livermore National Laboratory for the past eight years. 1975年，塔特拿到博士学位，其间除了念书，她还得忙著抚养第一次婚姻生下的女儿。 来自互联网

19 hoax   

v.欺骗，哄骗，愚弄；n.愚弄人，恶作剧

参考例句：

• They were the victims of a cruel hoax.他们是一个残忍恶作剧的受害者。
• They hoax him out of his money.他们骗去他的钱。

20 confirmation   

n.证实，确认，批准

参考例句：

• We are waiting for confirmation of the news.我们正在等待证实那个消息。
• We need confirmation in writing before we can send your order out.给你们发送订购的货物之前，我们需要书面确认。

21 cacophony   

n.刺耳的声音

参考例句：

• All around was bubbling a cacophony of voices.周围人声嘈杂。
• The drivers behind him honked,and the cacophony grew louder.后面的司机还在按喇叭，且那刺耳的声音越来越大。

22 neutron   

n.中子

参考例句：

• Neutron is neutral and slightly heavier than the proton.中子是中性的，比质子略重。
• Based on the neutron energy,the value of weighting factor was given.根据中子能量给出了相应的辐射权重因子的数值。

23 astronomical   

adj.天文学的，（数字）极大的

参考例句：

• He was an expert on ancient Chinese astronomical literature.他是研究中国古代天文学文献的专家。
• Houses in the village are selling for astronomical prices.乡村的房价正在飙升。