首页
登录
职称英语
【B1】 [br] 【B8】 [originaltext]The origin of Earth’s moon, the largest moon in the
【B1】 [br] 【B8】 [originaltext]The origin of Earth’s moon, the largest moon in the
游客
2023-07-13
71
管理
问题
【B1】 [br] 【B8】
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
expect
解析
转载请注明原文地址:http://tihaiku.com/zcyy/2832590.html
相关试题推荐
【B1】[br]【B11】[originaltext]Italiansareknownforthemandtheoriessugge
【B1】[br]【B5】[originaltext]Italiansareknownforthemandtheoriessugges
【B1】[br]【B3】[originaltext]Italiansareknownforthemandtheoriessugges
[originaltext]Doyouhaveatoughmathtestcomingup?Thenlistentosome
[originaltext]Doyouhaveatoughmathtestcomingup?Thenlistentosome
[originaltext]Parentsshouldstopblamingthemselvesbecausethere’snota
[originaltext]Parentsshouldstopblamingthemselvesbecausethere’snota
[originaltext]SomestudentsattheOpenUniversityleftschool20yearsago.
[originaltext]SomestudentsattheOpenUniversityleftschool20yearsago.
[originaltext]SomestudentsattheOpenUniversityleftschool20yearsago.
随机试题
Asapsychotherapistwithmanypatientsintheir20’s,Ican______thefacttha
圆管层流运动过流断面上速度分布为(式中r0为圆管半径):
学龄儿童应该合理食用各类食物,取得平衡膳食,一日中午餐热量占一日总热量的( )
在PowerPoint中放映当前幻灯片的快捷键为( )。A.Shift+F5
共用题干 DarkForcesDominateUniverseThee
覆冰天气时,观察外绝缘的覆冰厚度及冰凌桥接程度,覆冰厚度不超10mm,冰凌桥接长
下图是一块前后两面临街的矩形土地,总深度为30.00m,前街路线价(土地单价)为
工程质量控制关键点的文件中,不包括()A.质量控制关键点明细表 B.工序
(2021年真题)缆索吊装松索应按()顺序。A.拱脚段扣索、次拱脚段扣索、起重索
在某工程网络计划中,已知工作M自由时差为2天,总时差为5天,监理工程师检查实际进
最新回复
(
0
)