月球背面高地的形成分析-凯发k8官网

月球背面高地的形成分析
文章来源:未知 文章作者:meng 发布时间:2010-11-12 03:10 字体: [ ] 
(单词翻译:双击或拖选)

a 1(膨胀,凸出部分) of elevated topography(地势) on the farside of the moon--known as the lunar farside highlands--has defied explanation for decades. but a new study led by researchers at the university of california, santa cruz, shows that the highlands may be the result of tidal(潮汐的) forces 2 early in the moon's history when its solid outer crust floated on an ocean of liquid rock. ian garrick-bethell, an assistant professor of earth and planetary sciences at uc santa cruz, found that the shape of the moon's bulge can be described by a surprisingly simple mathematical function. "what's interesting is that the form of the mathematical function implies that tides had something to do with the formation of that 3(地形,地势) ," said garrick-bethell, who is the first author of a paper on the new findings published in the november 11 issue of science.

the paper describes a process for formation of the lunar highlands that involves tidal heating of the moon's crust about 4.4 billion years ago. at that time, not long after the moon's formation, the crust was decoupled from the 4(地幔) below it by an intervening ocean of magma(岩浆) . as a result, the gravitational pull of the earth caused tidal 5 and heating of the crust. at the polar regions, where the flexing and heating was greatest, the crust became thinner, while the thickest crust would have formed in the regions in line with the earth.

this process still does not explain why the bulge is now found only on the farside of the moon. "you would expect to see a bulge on both sides, because tides have a symmetrical effect," garrick-bethell said. "it may be that 6 activity or other geological processes over the past 4.4 billion years have changed the expression of the bulge on the nearside."

the paper's coauthors include francis nimmo, associate professor of earth and planetary sciences at ucsc, and mark wieczorek, a planetary geophysicist at the institut de physique du globe in paris. the researchers 7 topographical(地形的) data from nasa's lunar reconnaissance orbiter and gravitational data from japan's kaguya orbiter.

a map of crustal thickness based on the gravity data showed that an especially thick region of the moon's crust 8 the lunar farside highlands. the variations in crustal thickness on the moon are similar to effects seen on jupiter's moon europa, which has a shell of ice over an ocean of liquid water. nimmo has studied the effects of tidal heating on the structure of europa, and the researchers 9 the same 10(分析的) approach to the moon.

"europa is a completely different satellite from our moon, but it gave us the idea to look at the process of tidal flexing of the crust over a liquid ocean," garrick-bethell said.

the mathematical function that describes the shape of the moon's bulge can account for about one-fourth of the moon's shape, he said. although mysteries still remain, such as what made the nearside so different, the new study provides a mathematical framework for further 11 into the shape of the moon.

"it's still not completely clear yet, but we're starting to chip away(削弱,损害) at the problem," garrick-bethell said.



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1 ns3ze     
n.突出,膨胀,激增;vt.突出,膨胀
参考例句:
  • the apple made a bulge in his pocket.苹果把他口袋塞得鼓了起来。
  • what's that awkward bulge in your pocket?你口袋里那块鼓鼓囊囊的东西是什么?
2 czrzoc     
n.演戏,行为,假装;adj.代理的,临时的,演出用的
参考例句:
  • ignore her,she's just acting.别理她,她只是假装的。
  • during the seventies,her acting career was in eclipse.在七十年代,她的表演生涯黯然失色。
3 sgeyk     
n.地面,地形,地图
参考例句:
  • he had made a detailed study of the terrain.他对地形作了缜密的研究。
  • he knows the terrain of this locality like the back of his hand.他对这一带的地形了如指掌。
4 y7tzs     
n.斗篷,覆罩之物,罩子;v.罩住,覆盖,脸红
参考例句:
  • the earth had donned her mantle of brightest green.大地披上了苍翠欲滴的绿色斗篷。
  • the mountain was covered with a mantle of snow.山上覆盖着一层雪。
5 ea85fac2422c3e15400d532b3bfb4d3c     
n.挠曲,可挠性v.屈曲( flex的现在分词 );弯曲;(为准备大干而)显示实力;摩拳擦掌
参考例句:
  • flexing particular muscles allows snakes to move in several ways. 可弯曲的特殊的肌肉使蛇可以用几种方式移动。 来自电影对白
  • china has become an economic superpower and is flexing its muscles. 中国已经成为了一个经济巨人而且在展示他的肌肉。 来自互联网
6 blgzq     
adj.火山的;象火山的;由火山引起的
参考例句:
  • there have been several volcanic eruptions this year.今年火山爆发了好几次。
  • volcanic activity has created thermal springs and boiling mud pools.火山活动产生了温泉和沸腾的泥浆池。
7 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
参考例句:
  • 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》
8 d9c77c83f8c2ab289262fec743f08dd0     
v.位于或存在于(某物)之下( underlie的第三人称单数 );构成…的基础(或起因),引起
参考例句:
  • i think a lack of confidence underlies his manner. 我认为他表现出的态度是因为他缺乏信心。 来自《简明英汉词典》
  • try to figure out what feeling underlies your anger. 努力找出你的愤怒之下潜藏的情感。 来自辞典例句
9 tz2zxa     
adj.应用的;v.应用,适用
参考例句:
  • she plans to take a course in applied linguistics.她打算学习应用语言学课程。
  • this cream is best applied to the face at night.这种乳霜最好晚上擦脸用。
10 llmys     
adj.分析的;用分析法的
参考例句:
  • i have an analytical approach to every survey.对每项调查我都采用分析方法。
  • as a result,analytical data obtained by analysts were often in disagreement.结果各个分析家所得的分析数据常常不一致。
11 02de25420938593f7db7bd4052010b32     
(正式的)调查( investigation的名词复数 ); 侦查; 科学研究; 学术研究
参考例句:
  • his investigations were intensive and thorough but revealed nothing. 他进行了深入彻底的调查,但没有发现什么。
  • he often sent them out to make investigations. 他常常派他们出去作调查。
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