了解宇宙是如何运行的（2010）

How the Universe Works S06E08

Part 6 Dec. 22, 2021, 7:23 p.m.

And Caloris basin
is coated in carbon.
彗星中有很多碳
Comets have a lot
of carbon in them,
我们知道彗星会撞击行星
and we know that
comets hit planets.
所以很明显
So it's kind of obvious to say,
“碳从何而来？”
"where did the carbon
come from?"
嗯，彗星，但也许不是
Well, comets, but maybe not.
2016年，信使团队揭示了一个令人兴奋的新理论
In 2016, the messenger team
reveals an exciting new theory.
最大的陨石坑
Are the largest impact craters
暴露了更深的东西吗？
actually exposing
something deeper?
陨石坑是进入行星地壳下面的
Impact craters are windows
into the lower parts
一个窗口
of the crust of a planet,
陨石坑越大，撞击事件
and the larger
the impact crater,
从深处挖掘出的物质就越深
the deeper the impact event
并将其带到
has excavated
material from depth
我们能在表面看到的地方
and brought it to where
we can see it at the surface.
这些陨石坑揭示了一个转折
The craters reveal a twist.
使水星变得如此黑暗的碳
The carbon that makes
Mercury so dark
一直都在那里
had been there all along
是最初形成这个行星的物质的一部分
as part of the material
that first formed the planet.
当年轻的水星被撞击时
When young Mercury is hit,
parts of the surface
部分表面会变成熔岩海洋
are transformed
into an ocean of molten rock.
当岩浆海洋冷却时，它就会凝固
As this magma ocean cools,
it solidifies,
形成地壳
forming a crust,
地壳上有石墨
and sitting on top
of this crust, graphite,
碳的结晶形式
the crystallized form of carbon.
像石墨这样的含碳矿物
Carbon containing
minerals like graphite
最终会出现在
would end up near
the surface of Mercury
水星表面岩浆海洋的顶部
at the top of that magma ocean
因为这些矿物的密度
because those minerals
are a lot less dense
与传统岩石相比要小得多
than the conventional
rocky minerals
因为那些岩石含有大量铁和镍
that contain a lot of, you know,
它们的密度更大
iron and nickel.
Those are more dense.
它们倾向于下沉到行星的中心
They tend to sink to
the center of the planet.
那些较轻的元素，比如石墨
Those lighter elements
like graphite
会飘到顶部
would tend to float to the top.
但火山活动让新的玄武岩熔岩流
But volcanism covers the planet
覆盖了整个星球
in new basalt lava flows
这些熔岩流来自地表深处
coming from deep
below the surface
那里的碳没有下沉
where the carbon didn't sink,
这些熔岩埋葬了水星古老的地壳
and this lava buries
Mercury's ancient crust.
随着时间的推移，这些碳
Over time, that carbon
is covered up
被随后的熔岩流所覆盖
by subsequent lava flows,
但是这些在水星表面下方的这层碳
but there was
this layer of carbon
当物体撞击水星并在表面
waiting underneath
the surface of Mercury,
凿出洞时就会把隐藏在下面的
and as objects hit Mercury and
gouged out holes in the surface,
这一较暗的层暴露出来
it exposed this hidden
darker layer underneath.
被数十亿年的熔岩流覆盖
Covered by a billion
years of lava flows
并被巨大的撞击事件所揭示
and revealed
by giant impact events,
这肯定是……
one this is for sure...
水星的表面确实是一片地狱般的景象
Mercury's surface has been
a truly hellish landscape.
想象一下，在火山活动非常活跃的
Imagine that we're on
the surface of Mercury
前10亿年里
during that first billion years
如果我们生活在水星的表面
when volcanism was very active.
这些彗星和陨石从天而降
Raining down from the sky,
all these comets and meteorites
无情地撞击地表
just pelting
the surface mercilessly,
然后，在你的脚下
and then, beneath your feet,
这些熔岩会冒出来
there'll be all this
molten rock bubbling up.
在水星上的前十亿年里
Really an awful place to be
真是一个可怕的地方
in that first billion years
on Mercury.
数十亿年来
Over billions of years,
彗星和火山活动重塑了水星的表面
comets and volcanism reshaped
the surface of Mercury,
然而这颗行星还没有结束
and this planet is not done yet.
科学家们发现了绵延数百英里的巨大悬崖
Scientists find giant cliffs
stretching hundreds of miles.
看起来水星还活着
It seems Mercury is alive.
水星，一个被陨石坑和古老熔岩流覆盖的
Mercury, a small,
dark world covered in craters
小而黑暗的世界
and ancient lava flows,
但科学家在其表面发现了其他东西
but scientists find
something else on the surface.
大约2英里高的悬崖被称为断层崖
Towering cliffs around 2 miles
high known as fault scarps.
如果你此时正沿着
If you were walking
along one of these scarps
水星表面的悬崖行走
on the surface of Mercury,
就会遇见一个巨大的悬崖
there would be
this giant cliff face
绵延数百英里远，远远超过地平线
that would go on for miles
and miles well over the horizon,
所以你会走在一个几乎没有尽头的悬崖旁边
so you would be walking next
to an almost endless cliff.
最大的断层崖是“鲁普斯”（Rupes）
The largest fault
scarp is enterprise Rupes.
它有600多英里长，横跨德克萨斯州的宽度
At over 600 miles long, it would
span the width of Texas.
我们在地球上看到了断层崖
We see fault scarps on Earth,
这是构造活动的证据
evidence of tectonic activity.
行星科学家贾尼·拉德博参观了死亡谷的一处悬崖
Planetary scientist
Jani Radebaugh visits a scarp
然后进行讲解
in death valley to explain.
在我身后形成这条长长的、笔直的阴影线
This long, straight
line of shadows behind me
是因为死亡谷仍在不断地
formed because death valley
is still spreading apart
分散右边的物质
and the material on the right
这些物质从左边掉落下来
has dropped down from
the material on the left
形成了一个非常陡峭的断层崖
and left a really
sharp fault scarp.
在我身后你们看到的断层崖
The fault scarp
you see behind me,
还有我们在水星上看到的断层崖，都是由构造力形成的
and the ones we see on Mercury,
are formed by tectonic forces,
这些意味着
and this just means
that there are forces
行星内部存在着外力
inside of the planets,
这些外力导致地壳破裂
and those forces cause
breaks in the crust.
在地球上，地幔的热量传递
On Earth, transfer
of heat from the mantle
推动了大♥陆♥板块的运动
drives the movement
of continental plates.
这些板块在地球表面移♥动♥
These plates move around
the surface of the planet,
相互作用……
interacting with each other...
建造着山脉，裂谷，甚至大♥陆♥
Building mountains, rift
valleys, even continents.
水星上的断层崖意味着
Do the fault scarps on Mercury
它也有板块构造吗？
mean it also has
plate tectonics?
当你想到地球的板块构造时
When you think about
the Earth's plate tectonics,
有多个板块的岩石
there are multiple
plates of rock