英语听力：自然百科 行星旅行指南：火星 Mars—18

 There is no room to screw up on a trip like this, mental or otherwise. Once on Mars, you are likely to be stuck there for a year or more, waiting for a window of opportunity to ride home. And unlike a robot, the hopes and fears of the whole planet will be riding with you. 

 

I think that humans are going to do a better job of exploring Mars ultimately than robots ever can. 

 

Robots move really slowly, what is in every opportunity that had done in 5 years on Mars, 2 astronauts can probably have done in a week. 

 

As fast and as smart as we are, we still need mechanical help to scout(侦察) the course for Mars, the next robot rolling on to red dirt will be aptly named Curiosity. 

It is the size of a small car and it has a nuclear power source, so you don’t have to worry about dust accumulating on solar or radar¹ and things like that, and most importantly, it has the capability² to look for trace quantities of organic molecules³, so we have gone beyond now looking for evidence of habitability to actually looking for evidence of the building blocks of life. 

 

Whether it is alive or dead, a trip to this red planet has a lot to teach us about our lonely blue one and the universe beyond. 

 

Now if you have 2 planets that are next to each other in the same solar system, they both have independent origins of life, you would have to conclude that the chance of having life all over the universe indeed, even in other places in our solar system would be very high and you can basically go to the bet and bet on it. 

 

We are not going to Mars just to search for life, we are going to Mars to search for a second genesis (起源)of life. We’d like to find something that is different from us that doesn’t have same genetic⁴ history and genetic code that we have, and for my point of view, the more alien the better. 

 

Now the second possibility is that we find life on Mars but, my goodness, it has a genetic code exactly like us, it uses DNA⁵.  It is too coincidental. This is representing our cousins. Life, either arose on earth and went to Mars, or actually, more likely the life originated on Mars, and it was transported on a meteorite⁶ or a comet to the earth early on and in fact, our home planet is Mars.

1 radar   

n.雷达，无线电探测器

参考例句：

• They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
• Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。

2 capability   

n.能力；才能；(pl)可发展的能力或特性等

参考例句：

• She has the capability to become a very fine actress.她有潜力成为杰出演员。
• Organizing a whole department is beyond his capability.组织整个部门是他能力以外的事。

3 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。

4 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

5 DNA   

(缩)deoxyribonucleic acid 脱氧核糖核酸

参考例句：

• DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
• Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。

6 meteorite   

n.陨石；流星

参考例句：

• The meteorite in Jilin Exhibition Hall is believed to be the largest in the world.吉林展览馆的陨石被认为是世界上最大的。
• The famous Murchison meteorite smashed into the Australian ground in 1969.1969年著名的默奇森陨石轰然坠落在澳大利亚。