Study shows Moon younger than previous estimates
英语课
WASHINGTON, Aug. 17 (Xinhua) -- Latest research shows that the Moon could be younger than previous estimates. The findings were published online Wednesday in the Nature journal.
The prevailing 1 theory of the Moon's origin is that it was created by a giant impact between a large planet-like object and the proto-Earth. The energy of this impact was sufficiently 2 high that the Moon formed from melted material that was ejected into space. As the Moon cooled, this magma solidified 3 into different mineral components 4. Analysis of lunar rock samples thought to have been derived 5 from the original magma has given scientists a new estimate of the Moon's age.
According to this theory for lunar formation, a rock type called ferroan anorthosite, or FAN, is the oldest of the Moon's crustal rocks, but scientists have had difficulty dating FAN samples. The research team used newly refined techniques to determine the age of a sample of FAN from the lunar rock that was brought back to Earth by the Apollo 16 mission in 1972.
The team analyzed 6 the isotopes 8 of the elements lead and neodymium to place the FAN sample's age at 4.36 billion years. This figure is significantly younger than earlier estimates of the Moon's age that range as old as the age of the solar system at 4. 568 billion years. The new, younger age obtained for the oldest lunar crust is similar to ages obtained for the oldest terrestrial minerals -- zircons from western Australia -- suggesting that the oldest crusts on both Earth and Moon formed at approximately the same time, and that this time dates from shortly after the giant impact.
This study is the first in which a single sample of FAN yielded consistent ages from multiple isotope 7 dating techniques. This result strongly suggests that these ages pinpoint 9 the time at which the sample crystallized.
"The extraordinarily 10 young age of this lunar sample either means that the Moon solidified significantly later than previous estimates, or that we need to change our entire understanding of the Moon's geochemical history," Carnegie Institute of Science's geochemist and study author Richard Carlson said.
adj.盛行的；占优势的；主要的
- She wears a fashionable hair style prevailing in the city.她的发型是这个城市流行的款式。
- This reflects attitudes and values prevailing in society.这反映了社会上盛行的态度和价值观。
adv.足够地，充分地
- It turned out he had not insured the house sufficiently.原来他没有给房屋投足保险。
- The new policy was sufficiently elastic to accommodate both views.新政策充分灵活地适用两种观点。
（使）成为固体，（使）变硬，（使）变得坚固( solidify的过去式和过去分词 )； 使团结一致； 充实，巩固； 具体化
- Her attitudes solidified through privilege and habit. 由于特权和习惯使然，她的看法变得越来越难以改变。
- When threatened, he fires spheres of solidified air from his launcher! 当危险来临，他就会发射它的弹药！
（机器、设备等的）构成要素，零件，成分； 成分( component的名词复数 )； [物理化学]组分； [数学]分量； （混合物的）组成部分
- the components of a machine 机器部件
- Our chemistry teacher often reduces a compound to its components in lab. 在实验室中化学老师常把化合物分解为各种成分。
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》
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》
n.同位素
- The isotope ratio is directly used for comparing oils or gases.同位素比率直接用于比较各种石油或天然气。
- How to apply a radio isotope?如何运用放射性同位素？
n.同位素；同位素( isotope的名词复数 )
- the many isotopes of carbon 碳的诸多同位素
- Tritium is one of the mildest radioactive isotopes. 氚是最和缓的放射性同位素之一。 来自《简明英汉词典》
vt.准确地确定；用针标出…的精确位置
- It is difficult to pinpoint when water problems of the modern age began.很难准确地指出，现代用水的问题是什么时候出现的。
- I could pinpoint his precise location on a map.我能在地图上指明他的准确位置。
adv.格外地；极端地
- She is an extraordinarily beautiful girl.她是个美丽非凡的姑娘。
- The sea was extraordinarily calm that morning.那天清晨，大海出奇地宁静。