首页
登录
职称英语
【B1】 [br] 【B7】 [originaltext]The origin of Earth’s moon, the largest moon in the
【B1】 [br] 【B7】 [originaltext]The origin of Earth’s moon, the largest moon in the
游客
2024-02-14
6
管理
问题
【B1】 [br] 【B7】
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
however
解析
转载请注明原文地址:https://tihaiku.com/zcyy/3448855.html
相关试题推荐
[originaltext]Chrisisinchargeofpurchasingandmaintainingequipmentin
[originaltext]Chrisisinchargeofpurchasingandmaintainingequipmentin
[originaltext]Bowsandarrowsareoneoftheman’soldestweapons.Theygav
[originaltext]M:Right,let’sgetontothemarketingstrategy.W:Well,thema
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
[originaltext]Sportsmadgamesareveryusefulforcharactertraining.Int
随机试题
Ricci,45,isnowstrikingoutonperhapshisboldestventureyet.Heplans
【B1】[br]【B3】[originaltext]Asummaryofthephysicalandchemicalnatureofli
简述绩效考核的形式。
技师对无牙颌模型的某些区域用石膏填补倒凹,其目的主要为()A.节省时
A.燥 B.风 C.热 D.火 E.心诸痛痒疮,皆属于
有机磷中毒时,代谢失常的神经递质是A.多巴胺 B.乙酰胆碱 C.5-羟色胺
诊断甲状腺乳头状癌最重要的依据是( )。A.癌细胞核明显异型 B.癌细胞有大
在漫长的进化之路上,一些生物因为某几个基因突变,获得了较强的体温调控能力。以人体
()是比较适合于人力资源需求短期预测的方法。A.德尔菲法 B.人员核查法
公路施工企业投标行为由( )负责评价,履约行为由( )负责评价,其他行为由( )
最新回复
(
0
)