首页
登录
职称英语
【B1】 [br] 【B5】 [originaltext]The origin of Earth’s moon, the largest moon in the
【B1】 [br] 【B5】 [originaltext]The origin of Earth’s moon, the largest moon in the
游客
2023-07-13
56
管理
问题
【B1】 [br] 【B5】
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
Composed
解析
转载请注明原文地址:http://tihaiku.com/zcyy/2832587.html
相关试题推荐
[originaltext]MyfirstsemesterofcollegewastheworstI’vebeenthrough.
[originaltext]MyfirstsemesterofcollegewastheworstI’vebeenthrough.
[originaltext]MyfirstsemesterofcollegewastheworstI’vebeenthrough.
[originaltext]Bookswhichgiveinstructionsonhowtodothingsareverypo
[originaltext]M:Howdidthejobinterviewgothismorning?W:I’mquiteconfid
[originaltext]M:Howdidthejobinterviewgothismorning?W:I’mquiteconfid
[originaltext]M:Howdidthejobinterviewgothismorning?W:I’mquiteconfid
[originaltext]M:Howdidthejobinterviewgothismorning?W:I’mquiteconfid
[originaltext]M:Howdidthejobinterviewgothismorning?W:I’mquiteconfid
【B1】[br]【B11】[originaltext]Catsarecreaturesofhabit.Theyliketogot
随机试题
Youwillhearfiveshortrecordings.Foreachrecording,decidewhatthe
Whatdoesthespeakermeanwhenhesays"Idon’tthinkIneedtotellyouwhyth
【B1】[br]【B8】[originaltext]ThethirdofMarchisanexcitingdayforlittl
下面哪种行为既是消防安全违法行为,同时又是治安违法行为()。A.建筑设计单位不
女性,35岁,在温度计制造厂工作。由于温度掌握不好,温度计破裂,经常有汞蒸气外逸
嗳气频作,常随情绪变化者,见于A.胃阴虚证 B.胃气虚证 C.肝胃不和证
经返修或加固处理的分项工程、分部工程,虽然改变外形尺寸但仍能满足()要求,可按技
猩红热出疹期的体征不包括A.帕氏线 B.口周苍白圈 C.杨梅舌 D.柯氏斑
变配电装置的防火措施中,接地保护是一种必不可少的防护类型。下列关于其接地措施的说
有关肺通气阻力的叙述,下列哪项是的 A.肺通气阻力可分为弹性阻力和非弹性阻力
最新回复
(
0
)