martian methane mystery deepens 火星上甲烷深藏的秘密-凯发k8官网

martian methane mystery deepens 火星上甲烷深藏的秘密
文章来源:未知 文章作者:meng 发布时间:2009-08-06 06:21 字体: [ ] 
(单词翻译:双击或拖选)

1 on mars is produced and destroyed far faster than on earth, according to analysis of recent data.

最近的统计数据显示,火星上的甲烷产生和消亡比地球上的快多了。

the martian surface is very hostile to organics say scientists
the martian surface is very hostile to organics say scientists

scientists in paris used a computer climate model for the red planet to simulate observations made from earth.

it shows the gas is 3(不平坦地,不均衡地) distributed in the martian atmosphere and changes with the seasons.

the presence of methane(甲烷) on mars is 4(吸引人的,有趣的) because its origin could either be life or geological activity - including volcanism.

writing in the journal nature, franck lefevre and francois forget from the universite pierre et marie curie in paris describe how they used a computer model of the martian climate to reconstruct observations made by a us team.

dr lefevre says the chemistry of the martian atmosphere is still a mystery.

he told bbc news: "we put the 5(动力学) and chemistry as we know it in the model and tried to match the measurements, to reproduce the 2 distribution they saw from earth."

"the problem is if we just take into account the photochemistry(光化学) as we know it on earth and if we put it in the model, then we cannot reproduce the model and that was a surprise."

"the current chemistry as we know it is not consistent with the measurements of methane on mars."

"there is something else going on, something that lowers the methane lifetime by a factor of 600. so if the measurements are correct, we must be missing something quite important."

dr lefevre says the work shows that if there is a much faster loss for methane on mars there must also be a much stronger production of methane.

but he urges caution: "it's a real challenge to measure methane on mars from earth and we've got only one example of this uneven distribution."

the results the french team used were published in january this year in the journal science. they were gathered by an american team using a technique called 6 spectroscopy(红外光谱学) at three different ground-based telescopes to monitor about 90% of the planet's surface.

in 2003 "8" of methane were identified. at one point, the primary 7 of methane contained an estimated 19,000 tonnes of the gas.

dr michael mumma, director of nasa's goddard center for astrobiology and lead author on the previous paper, told bbc news it was vital to understand how methane was destroyed on mars and to explain how so much of the gas is produced and destroyed so quickly on the red planet.

dr mumma does not rule out a biological explanation for the phenomenon but says it is possible that geology alone could be responsible.

if the methane is produced by geological activity, it could either originate from active martian volcanoes or from a process called serpentinisation.

the latter process occurs at low temperatures when rocks rich in the minerals olivine(橄榄石) and pyroxene(辉石) react chemically with water, releasing methane.

in december, dr mumma's team will begin another study of the martian surface using the new technique of adaptive optics(自适应光学) at the european southern observatory's very large telescope (vlt) in chile. they hope to 9(折叠,复写) their earlier results.

dr lefevre says that if the variations are confirmed it would mean the martian surface is very hostile for organics. but this would not necessarily exclude the possibility that life or the remnants(剩余,残余) of past life persist below ground, where conditions could be more 10.

nasa is due to launch a $2.3bn nuclear-powered rover(漂流者,流浪者) known as mars science laboratory (also called "curiosity") to the planet in 2011.

under one possible 11, the european and us space agencies would then send a european orbiter to the red planet in 2016 to track down the sources of methane.

a subsequent 2018 launch opportunity would be taken by the european exomars rover, launching on a us 12 rocket. the proposal currently being discussed is that exomars should be joined by a slightly smaller rover in the class of the us spirit and opportunity vehicles that are on the surface today.

exomars and its smaller cousin could be targeted at the methane sources identified by the 2016 orbiter.



点击收听单词发音收听单词发音  

1 t1eyx     
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 akwwb     
adj.不平坦的,不规则的,不均匀的
参考例句:
  • the sidewalk is very uneven—be careful where you walk.这人行道凹凸不平—走路时请小心。
  • the country was noted for its uneven distribution of land resources.这个国家以土地资源分布不均匀出名。
3 9fzz51     
adv.不均匀的
参考例句:
  • fuel resources are very unevenly distributed. 燃料资源分布很不均匀。
  • the cloth is dyed unevenly. 布染花了。
4 vqyzm1     
adj.有趣的;迷人的v.搞阴谋诡计(intrigue的现在分词);激起…的好奇心
参考例句:
  • these discoveries raise intriguing questions. 这些发现带来了非常有趣的问题。
  • it all sounds very intriguing. 这些听起来都很有趣。 来自《简明英汉词典》
5 nuszqq     
n.力学,动力学,动力,原动力;动态
参考例句:
  • in order to succeed,you must master complicated knowledge of dynamics.要取得胜利,你必须掌握很复杂的动力学知识。
  • dynamics is a discipline that cannot be mastered without extensive practice.动力学是一门不做大量习题就不能掌握的学科。
6 dx0yp     
adj./n.红外线(的)
参考例句:
  • infrared is widely used in industry and medical science.红外线广泛应用于工业和医学科学。
  • infrared radiation has wavelengths longer than those of visible light.红外辐射的波长比可见光的波长长。
7 h2szm     
n.羽毛;v.整理羽毛,骚首弄姿,用羽毛装饰
参考例句:
  • her hat was adorned with a plume.她帽子上饰着羽毛。
  • he does not plume himself on these achievements.他并不因这些成就而自夸。
8 15625acbfa4517aa1374a6f1f44be446     
羽毛( plume的名词复数 ); 羽毛饰; 羽毛状物; 升上空中的羽状物
参考例句:
  • the dancer wore a headdress of pink ostrich plumes. 那位舞蹈演员戴着粉色鸵鸟毛制作的头饰。
  • the plumes on her bonnet barely moved as she nodded. 她点点头,那帽子的羽毛在一个劲儿颤动。
9 pvaxn     
v.折叠,复制,模写;n.同样的样品;adj.转折的
参考例句:
  • the dna of chromatin must replicate before cell division.染色质dna在细胞分裂之前必须复制。
  • it is also easy to replicate,as the next subsection explains.就像下一个小节详细说明的那样,它还可以被轻易的复制。
10 2t2zw     
adj.善良的,慈祥的;良性的,无危险的
参考例句:
  • the benign weather brought north america a bumper crop.温和的气候给北美带来大丰收。
  • martha is a benign old lady.玛莎是个仁慈的老妇人。
11 lzoxm     
n.剧本,脚本;概要
参考例句:
  • but the birth scenario is not completely accurate.然而分娩脚本并非完全准确的。
  • this is a totally different scenario.这是完全不同的剧本。
12 vocy5     
n.地图册,图表集
参考例句:
  • he reached down the atlas from the top shelf.他从书架顶层取下地图集。
  • the atlas contains forty maps,including three of great britain.这本地图集有40幅地图,其中包括3幅英国地图。
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