英语听力精选进阶版 9393

Is, or was there ever, life on Mars? It's a question that's excited scientists since the dawn of the space age. And right now, there are orbiters, landers, roving vehicles all over the surface of the red planet, analyzing¹ it. But it's still an open question: how habitable is our celestial² neighbor and what, if anything, could have inhabited it? Here are four key moments in the search to answer that question: In 1976, NASA's 'Viking' lander, was the first mission to look for microbial life in soil samples it grabbed from Mar's surface. It didn't find evidence of even the simplest, organic molecule³. Since then, some members of the Viking team have questioned whether they missed something in that initial analysis. But to this day, there's no accepted evidence of microbial life on Mars.

In July of 1996, NASA scientists announced the discovery of fossils of bacterial⁴ life in meteorites⁵ that they found in Antarctica—meteorites from Mars that had crashed into our planet12,000 years ago. After huge, initial excitement, NASA said that after two years of continuing to study that meteorites, those initial lines of evidence simply went away. But to this day, there are still scientists who maintain that initial analysis was valid⁶. Both NASA's 'Curiosity' rover and the European Space Agency's orbiter have detected whiffs of the gas methane⁷ on Mars. Now that's tantalizing⁸ because on Earth, the vast majority of methane comes from microbial life so future martian missions have set their sights on detecting exactly where that gas is coming from. Most recently, and possibly most excitingly, researchers have found the first evidence of an existing body of liquid water on Mars. It was found using radar⁹ and this is a sub-glacial lake under the southern polar ice cap of the red planet.

火星上现在或者曾经有过生命吗?自从人类进入太空时代，这个问题就刺激着科学家们的神经。当前，轨道飞行器、着陆器和探测车都在这颗红色星球的表面进行分析。但是这仍然是一个没有解决的问题：我们的星球邻居到底有多适合人类居住?如果可能，又有什么适合居住?在研究中有四个关键性的事件可以回答这个问题：1976年，美国宇航局的“海盗号”着陆器寻找其从火星表面上采集的土壤样品中是否有微生物，这是探测火星是否存在生命的第一个飞行器。它没有发现哪怕是最简单的有机分子的证据。自那以后，“海盗号”团队的一部分成员就质疑在最初的分析中他们是否遗漏了一些东西。但是直到今天，没有可以接受的证据表明火星上存在微生物。1996年7月，美国宇航局科学家宣布他们在南极的火星陨石里发现了细菌化石，这些陨石是1万2千年前从火星坠落到地球上的。在经历了最初的巨大惊喜后，美国宇航局表示经过两年对这些陨石持续不断的研究，那些证明存在细菌的最初的线条已经消失了。但是直到今日，仍然有科学家认为那些最初的分析是有效的。美国宇航局的“好奇号”火星探测器和欧洲航天局的轨道飞行器都探测到火星上存在甲烷气体。这一点令人兴奋，因为在地球上，绝大部分甲烷来自微生物，所以未来火星的探测任务将会把目标锁定在精确探测这些甲烷气体来自于火星哪里。在刚刚过去的不久前，出现了可能是最令人兴奋的一次发现，研究人员发现了火星上有液态水存在的第一个实体证据。它是由雷达发现的火星南极冰盖下的一个冰下湖。

1 analyzing   

v.分析；分析( analyze的现在分词 )；分解；解释；对…进行心理分析n.分析

参考例句：

• Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据，暴露出的问题甚至更大。 来自辞典例句
• He undoubtedly was not far off the mark in analyzing its predictions. 当然，他对其预测所作的分析倒也八九不离十。 来自辞典例句

2 celestial   

adj.天体的；天上的

参考例句：

• The rosy light yet beamed like a celestial dawn.玫瑰色的红光依然象天上的朝霞一样绚丽。
• Gravity governs the motions of celestial bodies.万有引力控制着天体的运动。

3 molecule   

n.分子，克分子

参考例句：

• A molecule of water is made up of two atoms of hygrogen and one atom of oxygen.一个水分子是由P妈̬f婘̬ 妈̬成的。
• This gives us the structural formula of the molecule.这种方式给出了分子的结构式。

4 bacterial   

a.细菌的

参考例句：

• Bacterial reproduction is accelerated in weightless space. 在失重的空间，细菌繁殖加快了。
• Brain lesions can be caused by bacterial infections. 大脑损伤可能由细菌感染引起。

5 meteorites   

n.陨星( meteorite的名词复数 )

参考例句：

• Small meteorites have left impact craters all over the planet's surface. 这个行星的表面布满了小块陨石留下的撞击坑。 来自《简明英汉词典》
• One theory about the existence of extraterrestrial life rests on the presence of carbon compounds in meteorites. 地球外存在生命的理论是基于陨星上存在碳化合物质这一事实的。 来自《简明英汉词典》

6 valid   

adj.有确实根据的；有效的；正当的，合法的

参考例句：

• His claim to own the house is valid.他主张对此屋的所有权有效。
• Do you have valid reasons for your absence?你的缺席有正当理由吗？

7 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

8 tantalizing   

adj.逗人的；惹弄人的；撩人的；煽情的v.逗弄，引诱，折磨( tantalize的现在分词 )

参考例句：

• This was my first tantalizing glimpse of the islands. 这是我第一眼看见的这些岛屿的动人美景。 来自《简明英汉词典》
• We have only vague and tantalizing glimpses of his power. 我们只能隐隐约约地领略他的威力，的确有一种可望不可及的感觉。 来自英汉非文学 - 历史

9 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。