了解宇宙是如何运行的（2010）

How the Universe Works S06E01

Part 5 Dec. 22, 2021, 7:22 p.m.

will eventually evaporate,
这是对如何看待黑洞的彻底转变
and that was a complete shift in
how to think about black holes.
根据霍金的说法
According to Hawking,
当黑洞不再吞噬物质时
when black holes
aren't eating material,
它们实际上会通过散发热辐射或热量而收缩
they actually shrink by emitting
thermal radiation or heat.
在这个过程中
In this process,
黑洞最终会完全蒸发掉
a black hole will eventually
evaporate completely,
这给科学家带来了一个问题
and this creates
a problem for scientists.
宇宙中的一切事物
Everything in the universe,
从原子到行星再到宇宙飞船
from atoms to planets
to spacecrafts,
都携带着有关它们是由什么组成的
carry information
about what they're made of,
它们运动的速度有多快、以及它们去过哪里的信息
how fast they're going,
and where they've been.
物理定律表明
The laws of physics state
这些信息不会从宇宙中丢失
that this information
can't be lost from the universe,
这应该适用于黑洞
and that should apply
to black holes.
所以如果一个物体
So if an object passes through
穿过黑洞的视界
the event horizon
of a black hole,
关于这个物体的所有信息
all the information
about that object
都变成了黑洞本身的一部分
becomes part
of the black hole itself.
一旦它们掉进去了，你所能看到的就是一个更重的黑洞
Once they've fallen in, all you
can see is a heavier black hole,
如果你没有观察的话，你不知道是什么东西掉进去的
and you don't know what fell in
if you weren't watching it.
这并不违反物理定律
Well, that doesn't violate
the laws of physics,
但如果黑洞继续蒸发
but if the black hole continues
to evaporate,
随着热辐射蒸发
evaporate, evaporate
with thermal radiation
然后消失
and then disappear,
那么之后就只有热辐射了
then all you have afterwards
is thermal radiation.
你没有任何信息，甚至在原理上
You have no information,
even in principle,
关于什么掉进去了
about what fell in.
而这个信息
And that information
is precisely
正是量子力学所说的不能丢失
what quantum mechanics
says can't be lost.
黑洞发出的热辐射
The thermal radiation
coming out of the black hole
不包含任何信息
contains no information.
这是一张白纸
It's a blank slate.
如果这种情况一直持续到黑洞蒸发
If this continues until
the black hole evaporates,
那么当黑洞消失时
then all the information
is completely lost
所有的信息都将完全丢失
when the black hole disappears.
如果这些信息消失了
If that information disappears,
那么量子力学的定律就被违反了
then the laws of
quantum mechanics are violated.
我们还不知道如何解决这个悖论
And we don't know how
to solve that paradox yet.
我们正试图将量子力学和相对论结合起来
We're trying to combine quantum
mechanics and relativity,
而我们第一次能够做到这一点
and the first time
we're able to do it
就导致了这个巨大的混乱
leads to this giant mess
that calls into question
它让我们对有关宇宙运行方式的基本假设产生了疑问
fundamental assumptions about
the way the universe works,
所以……这是一个问题
so... that's kind of a problem.
这个问题被称为“信息悖论”
The problem is known
as the information paradox,
如果科学家们想要找到答案
and if scientists are going
to find an answer to it,
他们就必须将两种理论统一起来……
they'll have to unify
their two theories...
广义相对论，大的规则
General relativity,
the rules of the large,
量子力学，小的规则
and quantum mechanics,
the rules of the tiny.
到目前为止，这被证明是不可能的
And so far,
that's proved impossible.
我认为物理学中最大的尴尬
I think the single
biggest embarrassment in physics
就是我们有这两种理论……
is that we have
these two theories...
描述大的广义相对论
General relativity
describing the big
和描述小的量子力学……
and quantum mechanics
describing the small...
他们根本就不合得来
That simply don't get along.
大自然显然知道它在做什么
Nature obviously knows
what it's doing,
但我们没有一个单一的、统一的解释
but we just don't have
a single, unified explanation.
在过去的几十年里
The past few decades,
当我们试图全面描述黑洞时
as we've tried to describe
black holes fully,
我们做的工作越多
the more work we've done,
我们得到的混乱就越多
the more of a tangled mess
we get.
这至少需要一个聪明的头脑
It will take at least
one brilliant mind
来弄清楚
to figure this out.
也许已经有人这么做了
Maybe someone already has.
经典黑洞有一个壳状的视界
The classical black hole has
a shell-like event horizon
任何物体都无法逃脱
beyond which nothing can escape.
根据信息悖论，当黑洞蒸发时
And according to
the information paradox,
信息就丢失了
information is lost
when a black hole evaporates.
但这里有一个激进的、令人费解的想法……
But here's a radical,
mind-bending idea...
如果黑洞有毛发呢？
What if black holes have hair?
霍金和他的合作者指出
What Hawking and his
collaborators pointed out
黑洞可以有柔软的毛发
is that black holes
can have soft hair,
如果这是真的，那将是
and if that's true,
that would be a way
能够封装所有进入黑洞的信息的
of encapsulating
all the information
一种方式
that went into the black hole.
科学家们提出，这些所谓的毛发
Scientists propose
that these so-called hairs
以某种方式储存了
somehow store the information
坠入黑洞的任何东西的信息
of whatever has fallen
into the black hole.
当黑洞蒸发时
The information
is then imprinted
这些信息就会被印在热辐射上
on the thermal radiation emitted
as the black hole evaporates.
这些毛茸茸的黑洞可以解决信息悖论
These hairy black holes could
solve the information paradox,
但它们完全只是理论
but they're
entirely theoretical.
这些都是很新的想法
These are really new ideas,
人们还在尝试着去理解它们
and people are still trying
to figure them out.
所以很难给出一个
So it's hard to give
a really good explanation
很好的解释……
of something that is...
这是正在形成的理论
This is theory in the making.
人们正在解决这个问题
People are working this out now.
解决信息悖论
Solving the information paradox
将科学推向了极限
is pushing science
to its limits.
但更大的问题是
But an even bigger problem
黑洞的中心
is sitting at the heart
of a black hole.
关于黑洞理论的最大问题
The big problem about
the idea of black holes
是在它的中心，有一个我们称之为奇点的东西
is that at its center, there's
what we call a singularity.
在这个奇点处，物质的密度是无限的
At this singularity,
matter has infinite density
而空间是无限弯曲的
and space is infinitely curved.
这听起来不像是物理学
That's not something that