宇宙（2007）

The Universe S01E06

Part 2 April 22, 2021, 8:11 p.m.

That's a brilliant lake!
确实非常可怕
来看看
Oh, man! Geez!
That is absolutely gorgeous!
欧,实在是太梦幻了
That did some serious damage.
造成如此大的破坏
Just imagine that this is theasteroid that slammed in to the Earth.
想象一下地球上的这些小行星撞击
This must have been happeningjust repeatedly,
不断重复地发生
doing real damageto the planet Earth.
在地球表面造成严重的破坏
And it's just a smallscale example
这只是一个小实验
of what must have happenedat the early Earth.
发生在早期地球的情况
Yes!
真棒
Some of the objects blastinginto infant Earth
一些撞击地球的星体
were over 300 miles in diameter.
直径超过300英里
The force of one such high velocityimpact created tremendous heat.
这种高♥强♥度撞击,产生了超高温
Earth began roastingfrom the inside.
地球内部开始变热
Iron and nickel meltedand sank to the core
铁和镍融化,汇集到地核
generating heatlike a massive furnace.
产生巨大热量就像炼钢炉
The outer rock, or magma,was completely melted
岩石与融化液态的岩浆不停转换
producing a molten ocean.
又产生大量的岩浆灰
The planet was a raging infernofloating in space,
地球是飘浮在宇宙中的狂热地狱
literally...hell on Earth.
完全的,人间炼狱
The most severe impacts*could've sterilized the planet.
各种撞击更强烈地袭击地球
You've got a steam atmosphere and heaton the entire surface of the Earth
地球表面只有蒸汽
above sterilization temperatures.
并且这样的高温,跟消毒柜一样
Formation of the Earth's core, sometimescalled the great iron catastrophe,
地核的形成
通常称之为铁核对流
occurred within the first 40 millionyears of our planet's existence,
在地球诞生的最初4千万年
and it had a profoundeffect on our future.
并对我们的未来产生了深远的影响
Within the iron core,
得益于地球的铁质核心
the rotating ball of molten irongenerated a remarkable magnetic field.
不断旋转对流逐渐产生了地磁场
This set up the conditionsfor a habitable planet.
是地球适合生存的必须条件
By getting all the iron downto the centre of the planet
地心铁的聚集
you had a solid corethat eventually drove
产生固态内核,最终
the protective magnetic fieldthat surrounds our planet.
地磁场像盾一样环绕着地球
Without the magnetic field
如果没有地磁场
Earth would be an airless wastedevoid of life.
地球将没有空气,无法生存
A gusty wind of materials
太阳粒子风来到地球
speeds from the Sun past Earth ata million miles an hour,
以每小时100英里的速度
and could erode our atmosphereto nearly nothing
把大气不断的吹离,直到完全消失
in a few million years.
也只需几十万年
But Earth's magnetic fielddeflects the solar wind
但是,地磁场保护着地球,抵御太阳风
and preserves our air.
保住了大气层
But even with a magnetic field
即使有磁场保护
violence and chaos continuedto plague our planet.
地表仍充满炎热和混乱
Above the Earth's iron core,
由于炎热的铁核
its rocky mantlewas melting
外层的岩石被融化
forming volcanoes thatrose to the surface
形成突出地表的火山
and burped up noxiousgases and lava.
不断释放有毒气体和火山灰
And the collisionskept coming.
同时小行星撞击依然不断发生着
One impact would forever changethe course of Earth's history
地球形成史上一次重要撞击改变了这一切
and the fate of mankind.
人类的宿命
About 50 million yearsafter the Earth began forming
地球诞生5千万年后的某时
it experienced a collision that wouldsteer it in a new direction.
一个巨大的撞击改变了地球发展方向
An object the size of Mars
一个火星大小的星体撞击地球
slammed right into Earth, whichwas already 80% of its total size.
拥有当时地球体积80%大小
The explosive impact meltedboth the planets' outer layers
巨大爆♥炸♥融化了两个星球的外表
and fused the two togetherto form a larger Earth.
融合并形成了一个更大的地球
Some molten debris that didn't blendtogether coalesced to shape our Moon.
一些散落的其他碎片
结合在一起形成了月球
Planetary scientist Bill Hartmann,first proposed this theory
星体研究专家比尔,首先发表了这样的理论
after NASA's first mission to the Moon.
在NASA的第一次登月任务之后
When the Apollo astronautsbrought back rocks from the Moon
阿波罗宇航员带回来一些岩石
可以了解这些岩石的产生
and we could actually see whatthe rocks were made of,
they found out that...
最后发现
the rocks are likelava that you can find on Earth.
这些岩石非常像地球上发现的火山岩
Which tells you that the Moon materialand the Earth material are very similar.
这表明地球和月球的构成
非常相似
Earth's intimaterelationship with its moon
与地球关系密切的月球
gave the growing planeta competitive edge.
给地球成长带来诸多好处
The Moon is what causesthe seasons because
月球的存在,导致
some parts of the earthen NorthPole is tilted toward the Sun
在一年的某些时候北极朝着太阳
and later on the South Poleis tilted toward the Sun.
另一些时间,南极朝着太阳
The Moon holds that tilt steady. Thevarious gravity forces that are exerted
月球一直保持着一个倾角
万有引力作用下
tend to act in a way that holdsthat steady.
始终保持在一个固定倾角
After the epic collision whichcreated our moon,
在这次创造了月球的伟大的碰撞中
our planet was over 90%of its total mass.
地球获得了超过90%的物质
The planetary formation process
这个地球形成过程
involves almosta biological competition
使地球具有生物进化的基础
of many bodies bashinginto each other at very high speeds.
来自于这些高速撞击获得的物质
When the collisions subsided nearly3,9 billion years ago,
当39亿年前,碰撞停止时
our solar system was leftwith eight planets.
太阳系形成了8大行星
Or nine if you still count Pluto.
包括冥王星则有9大行星
Earth secured the thirdorbital position from the Sun,
地球处在了绕日运行的第三个位置
which is now 93 million miles away.
离太阳930万英里
Planets don't like each other,
几大行星各不相同
because they're gravitationallytugging each other.
取决于各自的引力
So they're equally spaced.
排列着
Each planet is a certainfraction further from the Sun.
每个行星都一个一个隔着一定的距离
The objects that didn'tbecome planets became refugees.
这些是太阳系中的流浪者
Asteroids, made of rock and iron,
这些小行星大多由石块和铁构成
found asylum in the Asteroid Beltbetween Mars and Jupiter.
存在于火星与木星的轨道之间
Comets, composed of icesdust and rock,
彗星由冰,尘土和石块构成
sought shelter in the Kuiper Belt,
一些存在于太阳系的古比皮带
just beyond the planet Neptune.
位于海王星轨道外层
Others migrated to the Oort Cloud,over a trillion miles from Earth.
另一些聚集成奥尔特云远离地球10亿英里以外的地方
This battered Porschesare a good analogue
非常相似于这些撞坏的保时捷
to the early Solar System,the comets and asteroids
包含着大量小行星和彗星的早期太阳系
that survived the early days.
这些小星体从诞生之初幸存下来
And like these cars, which arekept here for their parts,
同这些车一样保存着其所有部件
we can also ** comets and asteroidsfor vital parts
我们依然可以去寻找这些重要部件
that have been storedsince the formation of the Solar System.
这些太阳系诞生之初就形成的小星体
Over the courseof Earth's history,
在地球形成历史中
many misguided asteroidshave strayed off their orbital path
一些小行星可能改变了自己的运行轨道
and landed on our planetas meteorites.
落到地球上,成为地球的一部分
Over the years, scientists haveanalysed these meteorites
近年来,科学家们分♥析♥了这些外来物
and determined their agethrough radioactive dating.
通过放射性同位素衰减测其年龄
And since meteorites were formed atthe same time as our planets,
由于它们与地球同时期诞生
they provide the age of Earth.
这也得出地球的年龄
Roughly 4.5 billion years old.
大约45亿年
Scientifically this is fantastic.
科学家的这种特别思路
It's like looking atyour family history
就像寻找你的家族历史
and finding pieces of your first relativeall the way back in Earth's history.
想办法找出最初的家传物品
追溯他们的历史
They're still out there.
虽然在外漂流很久
Asteroids and comets
小行星和彗星们
may also shed light
同时可能又是我们
on the originsof water on our planet.
地球上水的来源
3.9 billion years ago,
39亿年前
the Earth cooled, forming a thicksilicate crust over its mantle,
地球开始冷却,形成坚硬的硅酸盐外壳
覆盖在铁镍内核之外
an iron and nickel core.
Warm liquid soon covered theplanet's surface,
很快地,温暖的地面覆盖了大量的水
except for a few volcanic islandsdotting the globe.
除了点缀在地球上的一些火山岛
One of the Earth'slucky properties
地球的又一个特别幸运之处
is that it happened to be bornin just the right place,
是诞生在一个恰当的地方
in what's calledthe habitable zone.
这是一个适合生存的区域
It's the right distance from the Sun,
跟太阳保持足够的距离
where its ocean does notboil away,
海洋不会被蒸发
but not too hot.
因为不是太热
Or too far away,where its ocean freezes over.
同样又离太阳不是太远海洋也不至于被冰冻
But where did Earthget all this water?
但是地表的这么多水来自何方?
One view is that watercame from volcanoes,
一种假说,认为是来自于火山爆发
which have been around sincethe early formation of Earth.
这些早期地球上所存在的大量火山
Volcanoes spewed out massiveamounts of steam into the atmosphere.