章节大纲

  • A hot, volcanic landscape with a red sky and a large sun in the background.

     

    What was early Earth like?
    ::早期地球是什么样子的?

    Earth was not always the  planet  it is today. In its earliest days, Earth was scorching hot. It did not have an  atmosphere  or  water . If life originated early on, it was wiped out by the terrible conditions.
    ::地球并不总是今天的地球。在最初的年代,地球正在燃烧,没有大气层或水。如果生命起源于早期,那么它就会被可怕的条件所毁灭。

    Formation of Earth and Moon
    ::地球和月球的形成

    Material at similar distances from the   collided together to form each of the planets. Earth grew from material in its part of space. The Moon’s origin is completely different from Earth’s.
    ::地球的起源与地球完全不同。 地球的起源是月球的起源。 地球的起源与地球的起源是完全不同的。 地球的起源与地球的起源是完全不同的。 地球的起源与地球的起源是完全不同的。

    Earth Forms
    ::地球表

    Earth formed like the other planets. Different materials in its region of space collided. Eventually, the material made a planet. All of the collisions caused Earth to  heat  up.   and metal melted. The molten material separated into layers. Gravity pulled the denser material into the center. The lighter  elements  rose to the surface ( Figure   ). Because the material separated, Earth’s  core  is made mostly of iron. Earth’s  crust  is made mostly of lighter materials. In between the crust and the core is Earth’s mantle, made of solid rock.
    ::地球形成与其他行星一样。 不同材料在其空间区域相撞。 最终, 材料制造了一个行星。 所有碰撞都导致地球升温, 金属熔化。 熔化材料被分离成层层。 重力将较稠密的物质拉入中心。 较轻元素升到表面( 图 ) 。 由于材料分离, 地球核心主要由铁组成。 地壳主要由较轻的材料组成。 在地壳和核心之间, 地壳和核心之间是由坚固岩石组成的地壳。

    Earth's layers: crust, mantle, liquid outer core, and solid inner core.

     

    Earth's layers.
     ::地球的层

    Moon Forms
     ::月表

    This  model  for how the Moon formed is the best fit of all of the  data  scientists have about the Moon.
    ::这个模型说明月球是如何形成的 是所有关于月球的数据科学家 最合适的模型。

    In the early  solar system , there was a lot of space debris.   flew around, sometimes striking the planets. An asteroid the size of   smashed into Earth. The huge amount of  energy  from the impact melted most of Earth. The asteroid melted too. Material from both Earth and the asteroid was thrown out into  orbit . Over time, this material smashed together to form our Moon. The  lunar  surface of the Moon is about 4.5 billion years old. This means that the collision happened about 70 million years after Earth formed.
    ::在早期的太阳系中,有很多空间碎片. 飞来飞去, 有时撞击行星。 一颗小行星, 其大小被撞入地球。 撞击产生的大量能量也融化了大部分地球。 小行星也被熔化了。 来自地球和小行星的材料都被抛出轨道。 随着时间的推移, 这些材料一起碎裂成我们的月球。 月球的月球表面有45亿年的历史。 这意味着撞击发生在地球形成7000万年后。

     

    Summary
     ::摘要

    • Earth grew from material that collided in its part of space.
      ::地球生长自在其空间部分相撞的物质。
    • The material melted and gravity separated it into layers.
      ::材料熔化,重力将材料分离成层。
    • An enormous asteroid struck Earth. The material flew into orbit and came together to form the Moon.
      ::一颗巨大的小行星撞击了地球 材料飞入轨道 聚集在一起组成月球

    Review
    ::回顾

    1. How did Earth form?
      ::地球是怎样形成的?
    1. How did Earth material separate into layers?
      ::地球物质如何分解成几层?
    1. How did the Moon form?
      ::月球是怎样形成的?