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  • General

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  • 月球的形成

    A lunar rock specimen displayed with a measuring scale and labeled block.

     

    Why is this called the Genesis Rock?
    ::为什么这叫创世纪之岩?

    The Genesis   was brought from the Moon to Earth by Apollo 15 astronauts. The rock is only 100 million years younger than the  solar system  and comes from the Moon's original  crust .
    ::阿波罗15号宇航员将创世纪从月球带回地球,岩石比太阳系还小1亿年,来自月球最初的地壳。

    How the Moon Formed
    ::月月如何形成

    One of the most unique features of  planet  Earth is its large Moon. Unlike the only other natural  satellites  orbiting an  inner planet , those of  , the Moon is not a captured  . Understanding the Moon’s birth and early history reveals a great deal about Earth’s early days.
    ::地球最独特的特征之一是其庞大的月球。 与环绕一个内行星的唯一其他自然卫星 — — 月球卫星 — — 不同,月球并不是被俘虏的。 了解月球的诞生和早期历史揭示了地球早期的许多东西。

    Features of the Moon
    ::月球的特征

    To determine how the Moon formed, scientists had to account for several lines of evidence:
    ::为了确定月球是如何形成的,科学家们必须说明若干方面的证据:

    • The Moon is large; not much smaller than the smallest planet, Mercury.
      ::月球是巨大的,并不小于最小的行星,水星。
    • Earth and Moon are very similar in composition.
      ::地球和月球的构成非常相似。
    • Moon’s surface is 4.5 billion years old, about the same as the age of the solar system.
      ::月球表面有45亿年的历史,与太阳系时代差不多。
    • For a body its size and distance from the  , the Moon has very little  core ; Earth has a fairly large core.
      ::对于一个体体来说,月球的大小和距离都很小;地球有相当大的核。
    • The oxygen  isotope  ratios of Earth and Moon indicate that they originated in the same part of the solar system.
      ::地球和月球的氧同位素比率表明,它们起源于太阳系的同一部分。
    • Earth has a faster spin than it should have for a planet of its size and distance from the Sun.
      ::地球的旋转速度比地球的大小和距离太阳的行星要快。

    Can you devise a “birth story” for the Moon that takes all of these bits of  data  into account?
    ::你能为月球设计一个“出生故事”吗? 它将所有这些数据都考虑在内?

    Moon's Birth Story
    ::月月的诞生故事

    Astronomers  have carried out computer simulations that are consistent with these  facts  and have detailed a birth story for the Moon. A little more than 4.5 billion years ago, roughly 70 million years after Earth formed, planetary bodies were being pummeled by asteroids and planetoids of all kinds. Earth was struck by a Mars-sized asteroid ( Figure   ).
    ::天文学家们进行了符合这些事实的计算机模拟,并详细介绍了月球的诞生故事。 在45亿多年前,也就是地球形成约7 000万年后的大约4 000万年前,行星体被各种小行星和行星所覆盖。 地球被火星大小的小行星撞击(图 ) 。

    Artist's depiction of the impact that formed the Moon from Earth and a Mars-sized asteroid.

     

    An artist’s depiction of the impact that produced the Moon.
    ::一位艺术家对月球撞击的描述。

    The tremendous  energy  from the impact melted both bodies. The molten material mixed up. The dense metals remained on Earth but some of the molten, rocky material was flung into an  orbit  around Earth. It eventually accreted into a single body, the Moon. Since both planetary bodies were molten, material could differentiate out of the  magma  ocean into core, mantle, and crust as they cooled. Earth’s fast spin is from energy imparted to it by the impact.
    ::撞击产生的巨大能量融化了两个体。熔化物将两种体融化。 熔化物将两种体体融为一体。稠密的金属留在地球上,但部分熔化的岩石材料被抛入环绕地球的轨道中。 最终,它被浓缩成一个单一体 — — 月球。 由于两个行星体被熔化,材料可以将岩浆海洋区分为冷却时的岩浆、地壳和地壳。 地球的快速旋转来自撞击给它带来的能量。

    Moon Rocks
    ::月月岩

    Lunar  rocks reveal an enormous amount about Earth’s early days. The Genesis Rock, with a date of 4.5 billion years, is only about 100 million years younger than the solar system (see opening image). The rock is a piece of the Moon’s anorthosite crust, which was the original crust. Why do you think Moon rocks contain information that is not available from Earth’s own materials?
    ::月球岩石揭示了地球早期的巨量。 创世纪岩石的日期为45亿年,比太阳系还小大约1亿年(见开场图像 ) 。 该岩石是月球的厌食地壳的一块块,这是原地壳。 为什么你认为月球岩石含有无法从地球自身材料中获取的信息?

    Can you find how all of the evidence presented in the bullet points above is present in the Moon’s birth story?
    ::能否发现上面子弹点上的所有证据 都出现在月球的诞生故事中?

    Summary
    ::摘要

    • The scientific explanation for how the Moon formed must take into account its features, such as its large size, internal structure, chemical composition, and spin.
      ::对月球如何形成的科学解释必须考虑到月球的特征,例如它的大小、内部结构、化学成分和旋转。
    • Earth was struck by a giant asteroid that melted the planet and asteroid and flung material into orbit where it coalesced and cooled to become the Moon.
      ::地球被一颗巨型小行星撞击,它熔化了行星和小行星,并将材料抛入轨道,凝聚并冷却成月球。
    • Moon's original crust is anorthosite, a feldspar-rich, light rock.
      ::月球原有的地壳是厌食动物, 富饶的费尔茨帕尔,轻岩。

    Review
    ::回顾

    1. Relay the story of how the Moon formed. Integrate as many of the Moon's features into the story as possible.
      ::重现月球如何形成的故事。 尽可能多地将月球的特征融入故事中。
    1. Why are Earth and Moon roughly the same age as the rest of the solar system?
      ::为什么地球和月球 大约和太阳系其他部分一样大?
    1. Why do scientists learn a lot about the early Earth from their studies of the Moon?
      ::为什么科学家从对月球的研究中 学到很多关于早期地球的知识?