了解宇宙是如何运行的（2010）

How the Universe Works S06E08

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

在下面的一层液态岩石上移♥动♥
that are moving around
on a layer of liquid rock below.
然而，水星基本上只有一个大板块
Mercury, however, has basically
just one big plate.
有一个固体表面覆盖了整个星球
There's a solid surface
that covers the entire planet.
水星有着不同的构造
Mercury has a
different kind of tectonics.
在数十亿年的时间里，它的液态核心已经冷却了
Over billions of years,
its liquid core cools,
随着内部冷却，这颗行星收缩了大约9英里
and as the interior cools, the
planet shrinks around 9 miles.
当某物冷却时，它会收缩
When something cools,
it contracts.
它会变小
It actually becomes smaller.
由于收缩，岩石和地壳起皱
Because of this contraction,
the rock and the crust wrinkles,
于是形成了巨大的悬崖
creating massive scarps.
你可以想象，如果你拿一个气球，把它盖在泥里
You can imagine, if you take
a balloon and cover it in mud
等泥干后
and let the mud dry,
你从气球里放一点空气
and then you let a little bit
of air out of the balloon,
会发生什么？
what's going to happen?
泥浆也会收缩
Well, that mud is going to
try to contract as well,
但它收缩不了，所以它会像这样裂开和折断
but it can't, and so it'll crack
and snap like that,
你就会得到这些逆冲断层，这些悬崖
and you'll get these
thrust faults, these scarps.
但对于水星来说，故事并没有就此结束
But for Mercury,
the story doesn't end there.
我们知道水星上的大断层是很久以前形成的
We understand that the large
fault scarps on Mercury formed
当时星球正在冷却
a long time ago
when the planet was cooling
地壳正在收缩和弯曲
and the crust was
shrinking and buckling,
但最近，信使号♥在水星附近
but more recently, messenger
has come very close to Mercury
发现了非常小的断层
and has found really
small fault scarps.
与一英里高的巨大陡坡不同
Unlike the giant
mile-high scarps,
这些小陡坡不到200英尺长
these small ones are less
than 200 feet in length.
这意味着什么？
What does this mean?
这些是小陡坡，问题是
These are small scarps,
and the thing is,
如果它们真的很古老
if those were really old,
撞击就会把它们抹去
impacts would have erased them,
所以它们应该早就从表面消失了
and so these should be
long gone off the surface.
所以这意味着它们是最近的
So that means that
they're recent.
他们是新的
They're new.
目前，水星被公认为
Right now, Mercury
has the record
太阳系中最小的行星
of being the smallest official
planet in the solar system,
但有没有可能最小的行星还在缩小呢？
but is it possible the smallest
planet is still shrinking?
水星在它的一生中一直受到轰击
Throughout its life,
Mercury has been bombarded.
冲击在巨大的老断层崖上会留下坑
Impacts have cratered
the large, old fault scarps.
这些小陡坡也应该被撞击留下的疤痕覆盖
The small scarps should be
covered in impact scars as well,
但它们是崭新的，这意味着它们很年轻
but they're pristine, which
means that they're young,
这意味着水星仍在收缩
and that means Mercury
is still shrinking.
水星实际上仍然是构造活动的
Mercury is actually
still tectonically active.
所以地球不再是太阳系中
So the Earth is no longer
唯一的构造活动行星
the only tectonically active
planet in the solar system.
我们已经看到水星有着惊人的历史
We've seen that Mercury
has a surprising history.
问题是，这颗行星本身仍然在冷却
The thing is, the planet
itself is still cooling,
仍然在收缩，即使在它
still contracting, even after
all of these billions
形成后的数十亿年之后太让人吃惊了
of years after it formed.
That's amazing.
乍一看，你可能会认为
At first, it may seem
that you could write this off
水星是靠近太阳的一块沉闷的、了无生气的小石头
as a dull, little, dead rock
close to the Sun,
但水星是一个有故事的星球
but Mercury has a story to tell.
这个故事一直延续到今天
A story that continues
to this day
尽管地球已经经历了一切
despite everything the
planet has gone through.
水星的日子过得很艰难在太阳系的历史上
Mercury has had it pretty
rough. It's had a tough time
它经历了一段艰难的时期
over the history
of the solar system.
它被行星抛来抛去
It has been tossed
around by planets.
它受到巨大的小行星和彗星的影响
It has been impacted by
gigantic asteroids and comets.
它是在萎缩
It is shrinking.
它受到太阳辐射的轰击
It's bombarded
by solar radiation.
这将使水星忍♥无可忍♥
That would tick anybody off,
而且在未来完全有可能
and it's entirely possible
that in the future,
水星会进行它的复仇
Mercury will get its revenge.
水星可能还有最后一招
Mercury could have
a final trick up its sleeve,
会威胁到我们的生存
one that threatens
our very existence.
信使号♥完成了水星最后的轨道运行
Messenger completes
its final orbit of Mercury...
然后撞向行星表面
and crashes into
the planet's surface,
对于一个有着撞击历史的世界来说
a fitting conclusion for a world
这是一个恰当的结论
with a history of impacts.
在信使号♥任务结束时
At the end of
the messenger mission,
我们对水星的看法发生了实质性的改变
our view of Mercury had
been substantially changed.
突然间，我们看到了一个完整的世界
We suddenly had a picture
of a complete world,
一个有着地狱般的高温
a place that had hellishly
high temperatures
和冰状的水的地方
and yet ices of water,
这种进化与它的任何行星兄弟
an evolution that didn't match
都不一样
that of any of its
sibling planets.
水星的未来会像它的过去一样不可预测吗？
Could Mercury's future be just
as unpredictable as its past?
现在，水星的未来看起来很光明……
Right now, the future
of Mercury looks bright...
非常,非常明亮
Very, very bright.
这都要归功于水星的巨大邻居
It's all thanks to
Mercury's massive neighbor.
太阳是一个由氢和氦组成的巨大球体
The Sun is a giant ball
of hydrogen and helium,
在其核心，发生了核聚变反应
and in the core, there's
a nuclear fusion reaction,
但随着时间的推移，太阳赖以生存的燃料，氢
but over time, the fuel that
the Sun runs on, hydrogen,
将开始消亡
will begin to die out.
它会消耗掉所有的燃料
It will actually burn
through all of its fuel.
当这种情况发生时，在它生命的最后阶段
When that happens,
in the final phases of its life,
太阳将膨胀成为一颗红巨星
the Sun will bloat up
to become a red giant star,
大小是现在的数百倍
hundreds of times the size
that it currently is.
随着太阳膨胀，它将吞噬水星
As the Sun expands,
it will engulf Mercury.
水星表面已经够糟糕的了
Being on the surface of Mercury
is bad enough right now.
现在要把它放在一个恒星里面
Now put it inside of a star.
所有的热量轰击这个星球
All of that heat
bombarding the planet
会把它蒸发掉
will literally boil it away.
但是水星是否有可能逃脱
But is there a chance
that Mercury could escape
这种炙烤呢？
this roasting?
我们需要考虑的不只是
There's not just
the evolution of the Sun