首页
登录
职称英语
【B1】 [br] 【B4】 [originaltext]The origin of Earth’s moon, the largest moon in the
【B1】 [br] 【B4】 [originaltext]The origin of Earth’s moon, the largest moon in the
游客
2023-07-13
65
管理
问题
【B1】 [br] 【B4】
The origin of Earth’s moon, the largest moon in the solar system, is still something of a mystery. There are some theories about its origin however. Now, keep in mind that a theory of the moon’s origin has to be consistent with two important facts. The first fact is that the Earth contains a lot of iron, most of it has an iron core. But the moon contains practically no iron. The second fact is that other than the difference in iron content, the moon and Earth are composed of the same minerals, a similarity not shared with any other planet or moon in our solar system. One of the earliest theories of the moon’s origin, I called it the Capture Theory, proposes that the moon was somehow captured by Earth’s gravitational force. This theory is improbable, however, because it assumes that the moon and Earth formed in different parts of the solar system. If this was true you would expect the moon’s composition to be much different from Earth’s composition, just as all the other planets in the solar system are so different from Earth. A second theory of the moon’s origin is more promising. It is sometimes referred to as the Mars Theory, because according to this theory, when Earth was still in formation, it was struck by a planet about the size of Mars. The impact caused the cores of the two planets to melt together and chunks of Earth’s crust to be thrown out into space. These chunks came together to form the moon. Now, remember, Earth’s crust is low in iron, because the iron is in Earth’s core, but high in various other minerals. This then accounts for why there is little iron but lots of other minerals on the moon.
选项
答案
practically
解析
转载请注明原文地址:http://tihaiku.com/zcyy/2832586.html
相关试题推荐
【B1】[br]【B5】[originaltext]Thehumanbraincontains10thousandmillionce
【B1】[br]【B2】[originaltext]Thehumanbraincontains10thousandmillionce
[originaltext]AblondeladyWalksintoaNewYorkCityBankandasksforth
[originaltext]AblondeladyWalksintoaNewYorkCityBankandasksforth
[originaltext]Theword"sports"firstmeantsomethingthatpeopledidinth
[originaltext]Theword"sports"firstmeantsomethingthatpeopledidinth
[originaltext]W:Whatareyoudoing?M:(20)I’morderingsomefilingcabineto
[originaltext]M:Uh,whereamI?W:Excuseme.Doyouneedanyhelp?M:Nab,I.
[originaltext]M:Uh,whereamI?W:Excuseme.Doyouneedanyhelp?M:Nab,I.
[originaltext]M:Boththechocolatecakeandtheicecreamareverydelicioust
随机试题
[originaltext]W:Goodmorning,Tom!Howareyou?M:Notbad!Whataboutyou?W:
[originaltext]Now,listentoPartTwooftheinterview.W:Absolutely.(6-1)But
HowIwishthatI________EnglishwellwhenIwasincollege!A、hadlearnedB、le
档案鉴定人员在判定档案价值时必须考虑保管费用因素,所谓保管费用,是指对以后保管档
(2020年真题)关于基金估值,以下表述正确的是().A.基金估值的第一
共用题干 SomethingMenDoNotLiketoDoEri
此时的处理原则是A.静脉滴注缩宫素 B.产房待产 C.肌内注射哌替啶 D.
各种运输方式内外部的各个方面的构成和联系,就是( )。 A.运输系统
一地下室外墙,墙厚h,采用MU10烧结普通砖、M10水泥砂浆砌筑,砌体施工质量控
某工程施工合同中约定2013年11月20日竣工,并于1个月内交付给发包方使用,但
最新回复
(
0
)