月球存水量可能被高估
文章来源:未知 文章作者:enread 发布时间:2014-04-02 06:13 字体: [ ]  进入论坛
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The amount of water present in the moon may have been overestimated1 by scientists studying the mineral apatite(磷灰石), says a team of researchers led by Jeremy Boyce of the UCLA Department of Earth, Planetary and Space Sciences. Boyce and his colleagues created a computer model to accurately2 predict how apatite would have crystallized from cooling bodies of lunar magma early in the moon's history. Their simulations revealed that the unusually hydrogen-rich apatite crystals observed in many lunar rock samples may not have formed within a water-rich environment, as was originally expected.
 
This discovery has overturned the long-held assumption that the hydrogen in apatite is a good indicator3 of overall lunar water content.
 
"The mineral apatite is the most widely used method for estimating the amount of water in lunar rocks, but it cannot be trusted," said Boyce, who is an adjunct assistant professor in the UCLA College of Letters and Science. "Our new results show that there is not as much water in lunar magma as apatite would have us believe."
 
The research was published online March 20 in the journal Science on and will be published in a future print edition.
 
For decades, scientists believed the moon was almost entirely4 devoid5 of water. However, the discovery of hydrogen-rich apatite within lunar rocks in 2010 seemed to hint at a more watery6 past. Scientists originally assumed that information obtained from a small sample of apatite could predict the original water content of a large body of magma, or even the entire moon, but Boyce's study indicates that apatite may, in fact, be deceptive7.
 
Boyce believes the high water content within lunar apatite results from a quirk8 in the crystallization process rather than a water-rich lunar environment. When water is present as molten rock cools, apatite can form by incorporating hydrogen atoms into its crystal structure. However, hydrogen will be included in the newly crystallizing mineral only if apatite's preferred building blocks, fluorine and chlorine, have been mostly exhausted9.
 
"Early-forming apatite is so fluorine-rich that it vacuums all the fluorine out of the magma, followed by chlorine(氯)," Boyce said. "Apatite that forms later doesn't see any fluorine or chlorine and becomes hydrogen-rich because it has no choice."
 
Therefore, when fluorine and chlorine become depleted10, a cooling body of magma will shift from forming hydrogen-poor apatite to forming hydrogen-rich apatite, with the latter not accurately reflecting the original water content in the magma.


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1 overestimated 3ea9652f4f5fa3d13a818524edff9444     
对(数量)估计过高,对…作过高的评价( overestimate的过去式和过去分词 )
参考例句:
  • They overestimated his ability when they promoted him. 他们提拔他的时候高估了他的能力。
  • The Ministry of Finance consistently overestimated its budget deficits. 财政部一贯高估预算赤字。
2 accurately oJHyf     
adv.准确地,精确地
参考例句:
  • It is hard to hit the ball accurately.准确地击中球很难。
  • Now scientists can forecast the weather accurately.现在科学家们能准确地预报天气。
3 indicator i8NxM     
n.指标;指示物,指示者;指示器
参考例句:
  • Gold prices are often seen as an indicator of inflation.黃金价格常常被看作是通货膨胀的指标。
  • His left-hand indicator is flashing.他左手边的转向灯正在闪亮。
4 entirely entirely     
ad.全部地,完整地;完全地,彻底地
参考例句:
  • The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
  • His life was entirely given up to the educational work. 他的一生统统献给了教育工作。
5 devoid dZzzx     
adj.全无的,缺乏的
参考例句:
  • He is completely devoid of humour.他十分缺乏幽默。
  • The house is totally devoid of furniture.这所房子里什么家具都没有。
6 watery bU5zW     
adj.有水的,水汪汪的;湿的,湿润的
参考例句:
  • In his watery eyes there is an expression of distrust.他那含泪的眼睛流露出惊惶失措的神情。
  • Her eyes became watery because of the smoke.因为烟熏,她的双眼变得泪汪汪的。
7 deceptive CnMzO     
adj.骗人的,造成假象的,靠不住的
参考例句:
  • His appearance was deceptive.他的外表带有欺骗性。
  • The storyline is deceptively simple.故事情节看似简单,其实不然。
8 quirk 00KzV     
n.奇事,巧合;古怪的举动
参考例句:
  • He had a strange quirk of addressing his wife as Mrs Smith.他很怪,把自己的妻子称作史密斯夫人。
  • The most annoying quirk of his is wearing a cap all the time.他最令人感到厌恶的怪癖就是无论何时都戴著帽子。
9 exhausted 7taz4r     
adj.极其疲惫的,精疲力尽的
参考例句:
  • It was a long haul home and we arrived exhausted.搬运回家的这段路程特别长,到家时我们已筋疲力尽。
  • Jenny was exhausted by the hustle of city life.珍妮被城市生活的忙乱弄得筋疲力尽。
10 depleted 31d93165da679292f22e5e2e5aa49a03     
adj. 枯竭的, 废弃的 动词deplete的过去式和过去分词
参考例句:
  • Food supplies were severely depleted. 食物供应已严重不足。
  • Both teams were severely depleted by injuries. 两个队都因队员受伤而实力大减。
TAG标签: water moon mineral
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