经济学人: 搜寻火星生命 (1)

 On earth, most of the methane¹ in the atmosphere has been belched² by living organisms, 在地球上，大气中的大部分甲烷都是由活着的生物体喷出的，

so finding the gas on Mars would be happy news for seekers after extraterrestrial life. 所以对探求者们来说，在火星上发现气体是仅次于发现地外生命的好消息。

Sadly, news announced on December 12th, at the annual meeting of the American Geophysical Union (AGU), in Washington, DC, was anything but happy. 不幸的是，12月12日在华盛顿特区举行的美国地球物理学会（AGU）年度会议上宣布的消息却让人开心不起来。

Preliminary results from ExoMars Trace Gas Orbiter, a European craft that has been circling Mars for the past two years, 欧洲的ExoMars微量气体探测轨道飞行器在过去两年中一直围绕火星盘旋，

give a thumbs-down to the idea that there is methane in its atmosphere. 该飞船发回的初步结果与火星大气中有甲烷的说法相悖。

Previous observations, from orbit and by telescopes on Earth, suggested Mars might sport traces of the gas. 从轨道发回的以及从地球望远镜中观察到的早期观察结果表明火星上或许有气体存在的痕迹。

These were backed up by data from Curiosity, an American Mars rover. 这些都得到了美国火星探测车好奇号的数据支撑。

In its six years crawling around a crater³ called Gale⁴ Curiosity has both detected methane 在六年的时间里，它一直围绕着盖尔环形山爬行，好奇号既探测到了甲烷

and recorded seasonal⁵ ups and downs of the stuff that cycle from a modest 0.25 parts per billion during the winter to 0.65ppbn in the summer, with spikes⁶ up to 7.0ppbn. 也记录下了这种物质季节性的波动，它稳定地维持在冬季的几十亿分之0.25到夏季的几十亿分之0.65之间，有时会攀升至几十亿分之7。

That cyclical pattern has intrigued⁷ researchers back on Earth. Broadly speaking, there are two possible sources for Martian methane. 那种循环模式引起了地球上研究人员的兴趣。一般来说，火星甲烷有两种可能的来源。

One is outer space, whence carbon-rich molecules⁸, some of which are likely to break down into methane, arrive constantly on meteors of various sizes. 一种是太空，那里有富含碳的分子，其中一些可能分解成甲烷，抵达大小各异的流星上。

The other is from under the planet's surface. 另一种是来自行星表面之下。

Methane from both sources will mix eventually into the atmosphere. 两种来源的甲烷最终将混入大气中。

But if the gas is coming from underground, it will be more concentrated near its source, and might well appear on a seasonal basis. 但是如果气体来自于地下，那么它将更加集中于起源头附近，并且有可能表现出季节性。

The process could be a geological or geochemical one that is encouraged by the relative warmth of summer. That would be interesting. 这一过程可以是地质性或地球化学性的，并受到了夏季相对温暖气候的鼓动。这很有趣。

Or it could be biological, with methane-generating bugs⁹ waking up during the summer months. 或者它可以是生物学过程，产生甲烷的虫子在夏季的几个月中醒来。

That would be headline-grabbing. For either to be the explanation of the seasonality¹⁰ observed by Curiosity, 这将会成为新闻焦点。不论好奇号观测到的季节性解释是哪一种，

the rover would have to have had the luck to land in an area of such methane seeps¹¹. But such lucky breaks do happen. 探测车将有幸着陆在这片甲烷渗出的区域。但是这种幸运的事确实发生了。

 

1 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。

2 belched   

v.打嗝( belch的过去式和过去分词 )；喷出，吐出；打（嗝）；嗳（气）

参考例句：

• He wiped his hand across his mouth, then belched loudly. 他用手抹了抹嘴，然后打了个响亮的饱嗝。
• Artillery growled and belched on the horizon. 大炮轰鸣在地平面上猛烈地爆炸。 来自《现代英汉综合大词典》

3 crater   

n.火山口，弹坑

参考例句：

• With a telescope you can see the huge crater of Ve-suvius.用望远镜你能看到巨大的维苏威火山口。
• They came to the lip of a dead crater.他们来到了一个死火山口。

4 gale   

n.大风，强风，一阵闹声（尤指笑声等）

参考例句：

• We got our roof blown off in the gale last night.昨夜的大风把我们的房顶给掀掉了。
• According to the weather forecast,there will be a gale tomorrow.据气象台预报，明天有大风。

5 seasonal   

adj.季节的，季节性的

参考例句：

• The town relies on the seasonal tourist industry for jobs.这个城镇依靠季节性旅游业提供就业机会。
• The hors d'oeuvre is seasonal vegetables.餐前小吃是应时蔬菜。

6 spikes   

n.穗( spike的名词复数 )；跑鞋；（防滑）鞋钉；尖状物v.加烈酒于( spike的第三人称单数 )；偷偷地给某人的饮料加入（更多）酒精（ 或药物）；把尖状物钉入；打乱某人的计划

参考例句：

• a row of iron spikes on a wall 墙头的一排尖铁
• There is a row of spikes on top of the prison wall to prevent the prisoners escaping. 监狱墙头装有一排尖钉，以防犯人逃跑。 来自《简明英汉词典》

7 intrigued   

adj.好奇的，被迷住了的v.搞阴谋诡计(intrigue的过去式)；激起…的兴趣或好奇心；“intrigue”的过去式和过去分词

参考例句：

• You've really intrigued me—tell me more! 你说的真有意思—再给我讲一些吧！
• He was intrigued by her story. 他被她的故事迷住了。

8 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。

9 bugs   

adj.疯狂的，发疯的n.窃听器( bug的名词复数 )；病菌；虫子；[计算机]（制作软件程序所产生的意料不到的）错误

参考例句：

• All programs have bugs and need endless refinement. 所有的程序都有漏洞，都需要不断改进。 来自《简明英汉词典》
• The sacks of rice were swarming with bugs. 一袋袋的米里长满了虫子。 来自《简明英汉词典》

10 seasonality   

季节性

参考例句：

• a high degree of climatic seasonality 明显的季节性气候变化
• Confinement. Seasonality of tourist trade, animals often 'contracted' to work. 限制，在旅游旺季时，动物们通常都得被迫“上工”。 来自互联网

11 seeps   

n.（液体）渗( seep的名词复数 )；渗透；渗出；漏出v.（液体）渗( seep的第三人称单数 )；渗透；渗出；漏出

参考例句：

• Water seeps through sand. 水渗入沙中。 来自《现代汉英综合大词典》
• Water seeps out of the wall. 水从墙里沁出。 来自《现代汉英综合大词典》