首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
For more than thirty years after astronauts first set foot on the Moon, scientists have been unable to unravel the mystery of wh
For more than thirty years after astronauts first set foot on the Moon, scientists have been unable to unravel the mystery of wh
admin
2010-01-13
29
问题
For more than thirty years after astronauts first set foot on the Moon, scientists have been unable to unravel the mystery of where the Earth’s only satellite came from. But now there is direct evidence that the Moon was born after a giant collision between the young Earth and another planet.
Previous studies of rocks from the Earth and the Moon have been unable to distinguish between the two, suggesting that they formed from the same material. But this still left room for a number of theories explaining how—for example, that the Moon and Earth formed from the same material at the same time. It was even suggested that the early Earth spun so fast it formed a bulge that eventually broke off to form the Moon.
Franck Poitrasson, and his colleagues at the Swiss Federal Institute of Technology have compared Moon rocks with rocks from Earth and discovered a surprising difference. They analysed the weight of the elements present in the rock using a highly accurate form of mass spectroscopy(光谱研究) that involves vaporising a sample by passing it through an argon (氩) flame. Although they appeared very similar in most respects, the Moon rocks had a higher ratio of iron-57 to iron-54 isotopes(同位素)than the Earth rocks. "The only way we could explain this difference is that the Moon and the Earth were partly vaporised during their formation," says Poitrasson.
Only the popular "giant planetary impact" theory could generate the temperatures of more than 1700℃ needed to vaporise iron. In this scenario, a Mars-sized planet known as Theia crashed into Earth 50 million years after the birth of the Solar System. This catastrophic collision would have released 100 million times more energy than the impact believed to have wiped out the dinosaurs—enough to melt and vaporise a large portion of the Earth and completely destroy Theia. The debris from the collision would have been thrown into orbit around the Earth and eventually coalesced to form the Moon.
When iron is vaporised, the lighter isotopes burn off first. And since the ejected debris that became the Moon would have been more thoroughly vaporised, it would have lost a greater proportion of its lighter iron isotopes than Earth did. This would explain the different ratios that Poitrasson has found.
Which of the following statement is NOT TRUE according to the passage?
选项
A、The Moon was born after a giant collision between the young Earth and another planet.
B、The Moon rocks had a higher ratio of iron 57 to iron 54 isotopes than the Earth rocks.
C、The Moon and the Earth have almost the same portion of iron.
D、This catastrophic collision would have released much more energy than the impact believed to have wiped out the dinosaurs.
答案
C
解析
在第一段末尾提到“there is direct evidence that the Moon was born after a giant collision between the young Earth and another planet”所以A正确。在第四段中提到,“the Moon rocks had a higher ratio of iron 57 to iron 54 isotopes than the Earth rocks”所以B也正确。在第五段中也提到,“This catastrophic collision would have released 100 million times more energy than the impact believed to have wiped out the dinosaurs”所以D正确,故选C。
转载请注明原文地址:https://kaotiyun.com/show/timi777K
0
在职申硕(同等学力)英语
相关试题推荐
Formillionsofyearsbeforetheappearanceoftheelectriclight,shiftwork,all-nightcableTVandtheInternet,theEarth’s
Therearehiddenfactorswhichscientistscall"feedbackmechanisms".Nooneknowsquitehowtheywillinteractwiththechangin
Accordingtothispassage,troublesontheroadareprimarilycausedby______.By"goodsense"(Paragraph2),thewritermeans_
Scientistsarehopingtoeliminatemalaria(疟疾)bydevelopingageneticallymodifiedmosquitothatcannottransmitthedisease.
BeforehighschoolteacherKimberlyRughgotdowntobusinessatthestartofarecentschoolweek,shejokedwithherstudents
Someofthesestudies(haveshown)thatalthoughsomepeoplehavetrouble(tofallasleep),othershavean(equally)difficultt
随机试题
下列哪些物质是磷酸果糖激酶-1的变构激活剂
神经根型颈椎病患者牵引时一般应该采用
本病例诊断可不予考虑的是为确诊此病人有无尿崩症,应首先进行哪项试验
洁净空调风管不得有()接缝。
假如张先生在去年的今天以每股25元的价格购买了1000股招商银行股票,过去一年得到0.2元的红利,年底时股票价格为每股30元,则其持有期收益率为()。
企业采购的物品大致可分为生产性材料和非生产性材料。()
现阶段,我国中小学教科书编写的直接依据是()。
下列关于我国国情的表述,不正确的是()。
Readthearticlebelowaboutanewproduct.Aresentences16-22"Right"or"Wrong"?Ifthereisnotenoughinformationtoanswer
A、Yellow.B、Red.C、Green.D、Black.A本题问“博物馆的屋顶是什么颜色”。文中提到“TheMuseumisyellow,whichstandsfortheemperor”。故A项“黄色”为正确答案。
最新回复
(
0
)