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
2024-02-14
20
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:https://tihaiku.com/zcyy/3448852.html
相关试题推荐
[originaltext]Chrisisinchargeofpurchasingandmaintainingequipmentin
[originaltext]Chrisisinchargeofpurchasingandmaintainingequipmentin
[originaltext]Chrisisinchargeofpurchasingandmaintainingequipmentin
[originaltext]Bowsandarrowsareoneoftheman’soldestweapons.Theygav
[originaltext]M:Right,let’sgetontothemarketingstrategy.W:Well,thema
[originaltext]M:Right,let’sgetontothemarketingstrategy.W:Well,thema
[originaltext]M:Right,let’sgetontothemarketingstrategy.W:Well,thema
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
[originaltext]W:Tonyisthebestcross-countryrunnerwe’veeverhadinthiss
随机试题
Giventheadvantagesofelectronicmoney,youmightthinkthatwewouldmove
HowdidtheEnglishChannelcomeintobeing?[br][originaltext]F:Tom,doyou
Fromthepassagewecaninfertaboois______.[br]Basedontheideaspresented
Heroinaddictiontodayisfoundchieflyamongyoungmenof【B1】______groups
[originaltext]M:MayIseeDeanWilliamsplease?W:DeanWilliamswon’tbeint
B
已知矩阵,则A2-2A-2E(其中E为2阶单位矩阵)的特征值是( )A.2,2
挥发性或气体药物常用的给药方法是______;混悬液或油溶制剂常用给药方法是__
A.清宫术 B.取适量内膜活检 C.测基础体温 D.经行24~48小时刮宫
瑞氏染液中起溶剂作用的是()。A.美蓝 B.伊红 C.天青 D.甲醇
最新回复
(
0
)