了解宇宙是如何运行的（2010）

How the Universe Works S01E02

Part 3 April 18, 2021, 7:55 p.m.

of black holes in the night sky.
当我们环顾银河系和其它星系
When we look around our
galaxy and other galaxies,
可以确定的是强大黑洞遍布宇宙
it's clear that the universe
is full of powerful black holes.
找到黑洞是一回事
Finding black holes is one thing.
弄清它们如何运作是另一回事
Figuring out how they work,
that's a whole different ballgame.
所谓不入虎穴, 焉得虎子
The only way to find
out is to visit one.
你要搭宇宙飞船穿越浩瀚的太空
You'd have to take a spacecraft
to cross the vastness of space
才能靠近黑洞
just to get close to it.
然后要进入黑洞
Then, you'd have to go
inside the black hole.
在那里, 现实世界彻底粉碎
There, you'd find a place
where reality breaks down
时间停顿
and time stands still.
宇宙中存在着数十亿个黑洞
There are billions of
black holes in the universe.
可以用望远镜和卫星探测到它们
We can detect them with
telescopes and satellites,
但我们并不知道它们的具体模样
but we don't actually know
what they're like up close.
虽然遥不可及
It's a long way off,
但科学家已思索探索黑洞的计划
but scientists are already speculating
about a mission to a black hole,
是深入宇宙最危险区域的单程旅行
a one-way trip to the most
dangerous place in the universe.
起初黑洞在物理学界引起一片哗然
Originally, physicists were
horrified at the idea of black holes.
他们企图否认黑洞的存在
They wanted to banish them
因为黑洞似乎打破了…
because the laws of physics as
we know them seem to break down
所有物理定律
at the instant of a black hole.
时间停止了
Time stops,
引力变得无限大
gravity becomes infinite.
这真是个噩梦
This is a nightmare.
人类显然绝不可能靠近黑洞
Obviously, we can't send humans
anywhere near a black hole.
但机械人呢? 当然可以
But a robot? Well. sure.
机械人探测器可以在即将越过…
A robotic probe could transmit data back
黑洞边缘时传回数据
just before it goes over the edge.
黑洞的这个边缘叫做事件穹界
That edge of a black hole
is called the event horizon.
至少在已知宇宙中它是时空的边缘
It's the edge of time and space,
at least in the universe we know.
我们称之为事件穹界
We call the event
horizon an event horizon
只是因为它将空间一分为二
quite simply because it
separates space into two regions.
它不是一个物理表面
It's not a physical surface.
当你穿过它时, 可能完全不察觉
You might not even notice it
if you were falling through it.
但一旦进去就万劫不复
But ultimately, once you're
inside of it, you're doomed.
当你接近事件穹界
As you approach the event horizon,
引力增强和奇异情形也开始显现
gravity gets stronger and very
strange things start to happen.
若你脚先入黑洞, 脚离黑洞较近
As you fall into a black hole feet first,
your feet are closer to the black hole
所以感受到的引力更强
and so the gravity
they feel is stronger.
你的头部离得较远
Your head is not quite as close,
所以感受到的引力较小
and so the gravity it feels is less.
所以你会被拉长
And basically, what happens
is you get stretched out,
双脚受到的牵引远大于头部
your feet are being pulled
much harder than your head
就像被两个壮汉拉伸的拖肥糖
and you're like a piece of taffy
being pulled between two strong people.
越接近, 你就变得越细长
As you get thinner and thinner and thinner,
as you get closer and closer and closer,
这个过程被称为意粉效应
you're undergoing a process
we call spaghettification,
因为你变成了一根又细又长的面条
because you're basically turned
into a long thin tube of pasta.
引力会将机械人探测器拉伸到极限
Gravity would stretch our
robotic probe to the limit,
然后将其撕碎
then rip it apart.
但假如探测器够坚固, 能继续前行
But imagine if the probe was strong
enough to survive and keep going.
一旦接近事件穹界, 一切会很离奇
As it gets close to the event
horizon, everything goes crazy.
引力大到无穷以至时间停顿
Gravity is so extreme, it stops time.
我们认为时间永无止尽
We think of time as being endless.
但在黑洞中, 时间可以说停顿了
However, in a black hole,
in some sense, time stops.
听来是无稽之谈, 但黑洞确实如此
This sounds like it's nuts,
but that's the way it works.
数学上得出这个结论
it's in the math.
它其实是宇宙构造的一部分
It's actually woven into the
fabric of the universe itself.
若你从远处遥望
If you were to watch from a distance,
探测器接近黑洞时似乎慢了下来
the robot probe would seem to slow down
as it gets closer to the black hole.
然后好像完全停顿了
Then, it would appear
to stop completely.
整个过程可能十分短暂
The whole process might
just take a brief moment,
但从外面看, 似乎慢到几乎静止
but from the outside, you appear
to freeze and fall ever more slowly.
你其实永远不可能看到…
You actually can never observe an object
物体穿过事件穹界的全过程
fall all the way through
the event horizon.
它在黑洞表面停顿了
It literally freezes at the surface
因为它的时钟和你的相比无限缓慢
because its clock is going
infinitely slowly compared to yours.
事实上探测器没有停下来
In reality, the probe
hasn't stopped at all.
它仍在前进和穿过事件穹界
It keeps going and
crosses the event horizon.
若它将镜头向后转动朝向黑洞入口
If the probe points its cameras backwards,
towards the entrance of the black hole,
会看到光线被吸进来
it will see light being sucked in.
若将镜头向前方, 起初只见到黑暗
If it points the camera forward,
at first, it sees only black,
但随着它继续向黑洞核心前行
but as it moves toward the
heart of the black hole,
会到达宇宙中最奇异地方
it encounters the most
bizarre place in the universe.
黑洞的巨大引力将一切…
The black hole's immense
gravity pulls everything down
拉到位于中心的小点上
to an unimaginably
small point at its centre
科学家称之为奇点
Scientists call it the singularity.
我们确实不知道黑洞中心发生甚么
We really just don't know what
happens at the centre of a black hole.
密度非常高以至物理定律都被打破
The densities are so great that the laws
of physics break down as we know them.
奇点的引力无穷大使时空失去意义
A singularity is a point of infinite gravity
where space and time become meaningless.
这个说法很荒谬
Now, that is ridiculous.
奇点的意思其实是我不知道
A singularity is basically a
word for saying, "I don't know,"
我毫无头绪
it's a word for saying, "I'm clueless."
直到现在科学家也无法回答
Even now, scientists can't
really answer the question,
黑洞究竟是甚么
"What is a black hole?"
令人有些不安, 当知道宇宙中存在
It's upsetting a little bit to think
that there are objects out there
违背物理定律的物体
that are breaking the laws of physics.
必然存在更高一级的定律
There must be bigger laws that are
being used by these black holes,
适用于黑洞并为黑洞所遵循
that are being obeyed
by these black holes,
只是我们还未知道
that we just don't understand yet.
唯一知道的是黑洞诞生于垂死恒星
Okay, so the one thing we do understand is
that black holes are born from dying stars.
而大多数黑洞很小, 大约直径20哩
And most are small,
around 20 miles across.
但现在科学家已发现有些黑洞很大
But now scientists have discovered
that some black holes are much bigger.
它们叫做超大质量黑洞
They're called supermassive black holes.
它们与整个太阳系的大小相当
They're the same size as
our entire solar system
其中一个就潜伏在银河系中心
and one of these monsters lies
at the heart of our own galaxy.
太阳系位于银河系之中
Our solar system lies
in the Milky Way galaxy.
它由数十亿恒星构成, 包括太阳
It's made up of billions
of stars, including our sun,
全部绕着中心一个神秘区域旋转
all revolving around a mysterious