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The most likely source of the water locked inside soils on the moon's surface is the constant stream of charged particles from the sun known as the solar wind, a University of Michigan researcher and his colleagues have concluded. Over the last five years, spacecraft observations and new lab measurements of Apollo lunar samples have overturned the long-held belief that the moon is bone-dry.
In 2009, NASA's Lunar Crater1 Observation and Sensing satellite, known as LCROSS, slammed into a permanently2 shadowed lunar crater(月球陨石坑) and ejected a plume3 of material that was surprisingly rich in water ice. Water and related compounds have also been detected in the lunar regolith(风化层), the layer of fine powder and rock fragments that coats the lunar surface.
But the origin of lunar surface water has remained unclear. Is it mainly the result of impacts from water-bearing comets and other chunks4 of space debris5, or could there be other sources? Theoretical models of lunar water stability dating to the late 1970s suggest that hydrogen ions (protons) from the solar wind can combine with oxygen on the moon's surface to form water and related compounds called hydroxyls(氢氧根), which consist of one atom of hydrogen and one of oxygen and are known as OH.
In an article published online October 14 in the journal Nature Geoscience, U-M's Youxue Zhang and colleagues from the University of Tennessee and the California Institute of Technology present findings that support solar-wind production of water ice on the moon.
The first author of the paper is Yang Liu of U-T. She is a U-M alumna6 who earned her doctorate7(博士学位) under Zhang, who is a professor in the Department of Earth and Environmental Sciences.
In the paper, the researchers present infrared8 spectroscopy and mass spectrometry analyses of Apollo samples that reveal the presence of significant amounts of hydroxyl inside glasses formed in the lunar regolith by micrometeorite(微小陨石) impacts.
When combined, the techniques of Fourier transform infrared spectroscopy and secondary ion mass spectrometry can be used to determine the chemical form of the hydrogen in a substance, as well as its abundance and its isotopic9 composition. Most of the infrared spectroscopy work was done at Zhang's U-M lab, and the mass spectroscopy was conducted at Caltech.
"We found that the 'water' component10, the hydroxyl, in the lunar regolith is mostly from solar wind implantation of protons, which locally combined with oxygen to form hydroxyls that moved into the interior of glasses by impact melting," said Zhang, the James R. O'Neil Collegiate Professor of Geological Sciences.
"Lunar regolith is everywhere on the lunar surface, and glasses make up about half of lunar regolith. So our work shows that the 'water' component, the hydroxyl, is widespread in lunar materials, although not in the form of ice or liquid water that can easily be used in a future manned lunar base."
The findings imply that ice inside permanently shadowed polar craters11 on the moon, sometimes called cold traps, could contain hydrogen atoms ultimately derived12 from the solar wind, the researchers report.
"This also means that water likely exists on Mercury and on asteroids13 such as Vesta or Eros further within our solar system," Liu said. "These planetary bodies have very different environments, but all have the potential to produce water."
The regolith glasses are called agglutinates, and the study reported in Nature Geoscience is the first to identify agglutinates as a new reservoir of OH on the moon -- an "unanticipated, abundant reservoir" of OH and water in the lunar regolith, according to the authors.
The researchers analyzed14 individual grains from Apollo 11 mare15 soil, Apollo 16 highland16 soil and Apollo 17 mare soil. The grains included agglutinates(胶合的) and impact glasses.
In addition to Liu and Zhang, authors of the Nature Geoscience report are Yunbin Guan, George Rossman and John Eiler of Caltech and Lawrence Taylor of U-T.
The work was funded in part by NASA cosmochemistry(宇宙化学) grants to Taylor and Zhang, by support from the Moore Foundation to the Caltech Microanalysis Center, and by a National Science Foundation grant to Rossman. A portion of the study was also supported by U-T's the Planetary Geosciences Institute.


1 crater WofzH     
  • 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。
2 permanently KluzuU     
  • The accident left him permanently scarred.那次事故给他留下了永久的伤疤。
  • The ship is now permanently moored on the Thames in London.该船现在永久地停泊在伦敦泰晤士河边。
3 plume H2SzM     
  • 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。
4 chunks a0e6aa3f5109dc15b489f628b2f01028     
厚厚的一块( chunk的名词复数 ); (某物)相当大的数量或部分
  • a tin of pineapple chunks 一罐菠萝块
  • Those chunks of meat are rather large—could you chop them up a bIt'smaller? 这些肉块相当大,还能再切小一点吗?
5 debris debris     
  • After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
  • Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上,导致蛀牙。
6 alumna 0zizAo     
n.女校友,女毕业生 (pl.alumnae)
  • I came across a old alumna in the street this morning.今天早上我在街上碰见一位老校友。
  • My alumni and alumna are present at my birthday party.我的男校友和女校友都出席了我的生日聚会。
7 doctorate fkEzt     
  • He hasn't enough credits to get his doctorate.他的学分不够取得博士学位。
  • Where did she do her doctorate?她在哪里攻读博士?
8 infrared dx0yp     
  • 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。
9 isotopic 7ad2ece915960e8c295e01a4d04cc192     
  • The isotopic signatures of most ancient limestones indicated the same process. 大多数古代石灰岩的同位素特征说明了同样的过程。 来自辞典例句
  • Isotopic discrimination is not likely. 同位素甄别是不可能的。 来自辞典例句
10 component epSzv     
  • Each component is carefully checked before assembly.每个零件在装配前都经过仔细检查。
  • Blade and handle are the component parts of a knife.刀身和刀柄是一把刀的组成部分。
11 craters 1f8461e3895b38f51c992255a1c86823     
n.火山口( crater的名词复数 );弹坑等
  • 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》
  • The battlefield was full of craters made by exploding shells. 战场上布满弹坑。 来自《现代英汉综合大词典》
12 derived 6cddb7353e699051a384686b6b3ff1e2     
vi.起源;由来;衍生;导出v.得到( derive的过去式和过去分词 );(从…中)得到获得;源于;(从…中)提取
  • Many English words are derived from Latin and Greek. 英语很多词源出于拉丁文和希腊文。 来自《简明英汉词典》
  • He derived his enthusiasm for literature from his father. 他对文学的爱好是受他父亲的影响。 来自《简明英汉词典》
13 asteroids d02ebba086eb60b6155b94e12649ff84     
n.小行星( asteroid的名词复数 );海盘车,海星
  • Asteroids,also known as "minor planets",are numerous in the outer space. 小行星,亦称为“小型行星”,在外太空中不计其数。
  • Most stars probably have their quota of planets, meteorids, comets, and asteroids. 多数恒星也许还拥有若干行星、流星、彗星和小行星。
14 analyzed 483f1acae53789fbee273a644fdcda80     
v.分析( analyze的过去式和过去分词 );分解;解释;对…进行心理分析
  • The doctors analyzed the blood sample for anemia. 医生们分析了贫血的血样。 来自《简明英汉词典》
  • The young man did not analyze the process of his captivation and enrapturement, for love to him was a mystery and could not be analyzed. 这年轻人没有分析自己蛊惑著迷的过程,因为对他来说,爱是个不可分析的迷。 来自《简明英汉词典》
15 mare Y24y3     
  • The mare has just thrown a foal in the stable.那匹母马刚刚在马厩里产下了一只小马驹。
  • The mare foundered under the heavy load and collapsed in the road.那母马因负载过重而倒在路上。
16 highland sdpxR     
  • The highland game is part of Scotland's cultural heritage.苏格兰高地游戏是苏格兰文化遗产的一部分。
  • The highland forests where few hunters venture have long been the bear's sanctuary.这片只有少数猎人涉险的高山森林,一直都是黑熊的避难所。
TAG标签: water moon soils