了解宇宙是如何运行的（2010）

How the Universe Works S11E02

Part 5 April 10, 2023, 10:20 a.m.

This is crazy young for Mars.
火星已经存在了数十亿年
Mars has been around
for billions of years.
五万年不算什么
50,000 years is nothing.
人类很久以前就在地球上了
Humans were around on Earth
that long ago.
这是最近的事
So this is really recent.
拉德博:基于我们最近经历的
RADEBAUGH: Based on
the fact that we had
这两次火星地震，再加上
these two Mars quakes recently,
plus the evidence of
最近这两次火星地震的证据
these two Mars quakes recently,
plus the evidence of
加上5万年前火山爆发的证据
the volcanic eruption
just 50,000 years ago,
我的意思是，现在我们不能说火星已经死亡
I mean, now we cannot
say that Mars is dead.
我们不得不说火星还活着
We have to say
Mars is active.
火山活跃的火星
ROWE:
A volcanically active Mars
表明它的内部可能仍然是温暖的——那么如果是这样
suggests its interior may
still be warm -- if it is,
为什么行星的磁场会消失？
why did the planet's
magnetic field die?
洞察号♥利用火星小地震的振动
Insight probes
deep into the interior of
深入探测这颗红色星球的内部
the Red Planet using vibrations
from small Mars quakes.
洞察号♥用这些来构建
Insight uses these to kind of
construct what the interior of
火星内部的样子
Mars was like,
因为这些波以不同的方式
because these waves
bounce off different layers
从火星内部的不同层反弹
inside the interior of Mars
in different ways.
洞察号♥的地震仪
ROWE: Insight's seismometer
builds a picture of Mars
通过完全重绘火星内部地图来构建火星的图像
by completely redrawing the map
of the interior of the planet.
拉德博:事实证明，地壳比我们想象的
RADEBAUGH: It turns out
the crust is thinner
要薄——只有12到23英里厚（19公里到37公里）
than we thought --
it's only 12 to 23 miles thick.
所以这是整个火星的图景
So there's this whole picture
of Mars that is unfolding in
所以这是整个火星的图景
So there's this whole picture
of Mars that is unfolding in
展现在我们面前，这与我们预测的
front of us that is
vastly different
大相径庭
than we ever predicted.
洞察号♥对火星新布局的改进揭示了
ROWE: Insight's new and improved
layout of Mars reveals
一个969英里深的地幔，围绕着一个富含金属的核心
a 969-mile-deep mantle
surrounding a metal-rich core.
洞察号♥对数据的新分♥析♥揭示了
New analysis of data from
Insight reveals the size of
火星核心的大小这是我们以前从未有过的
the core of Mars,
and we haven't had this before.
太令人兴奋了
It's so exciting.
半径大约是1100英里（1770公里）
It's about 1,100 miles
in radius.
这是火星体半径的一半多一点
This is a little more than
half the radius of the body,
它相当大，比我们对火星核心大小的预期
which is pretty big, and is
much bigger than we expected
它相当大，比我们对火星核心大小的预期
which is pretty big, and is
much bigger than we expected
要大得多
for the size
of the core of Mars.
火星更大的内核
ROWE:
Mars's larger core
约占行星质量的四分之一
makes up about a quarter
of the planet's mass.
洞察号♥前往火星中心的旅程
And Insight's journey to
还带来了另一个惊喜
the center of Mars
reveals another surprise.
兰扎:我们一直认为火星的核心
LANZA: We have always thought
that the core of Mars
早已凝固，一点也不温暖
was long since solidified
and wasn't warm at all.
但洞察号♥现在向我们展示
And Insight is now showing us
that actually,
实际上，部分核心可能仍处于熔融状态
part of the core is probably
still molten,
这令人震惊
which is shocking.
火星上有一个液态核，我的意思是，这太疯狂了
There's a liquid core at Mars.
I mean, this is crazy.
过去任务的数据可能有助于
ROWE: Data from past missions
may help
解释为什么火星核心仍然是液态的
explain why Mars's core
is still liquid.
科学家们在地壳中发现了高含量的硫
Scientists discovered high
levels of sulfur in the crust.
火星的硫含量似乎比地球多一点
Mars seems to have
a bit more sulfur,
至少在表面是这样
at least in the surface,
than Earth does.
如果我们将这种成分延伸到核心
If we extend that composition
to the core
并向铁镍核心中添加更多的硫
and add more sulfur to
the iron-nickel core,
这实际上会降低它的融化温度
that would actually reduce
its melting temperature,
这实际上会降低它的融化温度
that would actually reduce
its melting temperature,
这就有可能使这个核心在今天还是熔融的
making it possible for this
core to be molten today.
我们认为火星的内核在冷却和凝固时
ROWE: We thought that Mars
lost its magnetic field
失去了磁场
when the core
cooled and solidified.
但熔融的内核改变了一切
A molten core
changes everything.
那么，我们如何解释火星上即使有液体内核
Well, how can we explain
this lack of a magnetic field
却没有磁场呢？
at Mars even though
there's a liquid core?
好吧，要有磁场就需要
Well, in order to have
a magnetic field,
流体在运动，旋转和对流
you need the fluid to be moving
and rotating and convecting.
随着时间的推移，火星失去热量并冷却
ROWE: Over time, as Mars
lost heat and cooled down
随着时间的推移，火星失去热量并冷却
ROWE: Over time, as Mars
lost heat and cooled down
由于硫，它的核心保持熔融状态
its core stayed molten
thanks to the sulfur.
但是，由于热量较少
But, with less heat,
there was not enough
没有足够的能量来推动
energy to power the churning
convection of liquid metal
液态金属的搅动对流，从而产生电流
that creates
an electric current.
内核中的对流速度会减慢到
The convection in that core
would have slowed down
不会产生磁场的程度
to the point where no magnetic
field would be generated.
37亿年前，火星的磁屏蔽层消失
ROWE: 3.7 billion years ago,
Mars's magnetic shield dies.
太阳风无情的攻击
The solar wind's
relentless attack
将行星的大气层剥离
strips the planet of
its atmosphere.
随着大气层的消失
As the atmosphere disappears,
地表的水逐渐蒸发
water on the surface
gradually boils away.
但是星球上所有的水都消散了吗？
But did all of the planet's
water dissipate?
为了找到答案，我们的机器人再次组队
To find out,
our robots once again team up.
自从1971年第一个探测器访问火星以来
ROWE: Since the first probe
visited Mars in 1971,
已经有16个任务从轨道上对这颗红色星球进行了调查
16 missions have investigated
the Red Planet from orbit,
同时有10个着陆器探索了火星表面
while 10 landers
have explored the surface.
他们发现火星可能仍然是一颗活跃的行星
They've revealed Mars may
still be an active planet,
曾经有适合生命生存的条件
one that once had the right
conditions for life.
火星曾经被认为是一个干燥、干旱
Mars used to be
thought of as this dry,
不适宜居住的环境
arid, inhospitable environment.
多亏了最近的火星任务
And thanks to the recent
Mars missions,
我们现在知道它们可以维持生命
we know now that they could
have sustained life.
今天，火星内部
ROWE: Could there be any
ancient Martian
是否还隐藏着古代的水？