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SciShow Space is supported by Brilliant.org.
《太空科学秀》由Brilliant.org赞助播出。
When people talk about black holes, there's one thing that pretty much always comes up:
人们在讨论黑洞的时候，总会提到一件事，那就是：
Black holes get their name because the infinitely tiny, infinitely dense point in the center has a gravitational pull so strong that even light can't escape.
黑洞得名于此是因为其中心极小、密度极高，引力极大，就连光也无法逃脱。
The thing is, that might not always be true.
不过，这个说法或许并不属实。
For the past half century, basically as long as we've known black holes are a thing,
过去半个世纪以来，也可以说是人类知道有黑洞这么个东西以来，
astrophysicists have been debating the existence of something that should be a black hole, except it's neither black nor a hole.
天体物理学家一直在探讨可能有一个黑洞一样的东西存在，只不过他们没想到这个东西既不黑，也不是个洞。
They're called naked singularities, and if they exist, they'll rewrite physics as we know it.
他们描绘的是裸奇点，而如果这种裸奇点当真存在的话，人类将改写物理学。
When a star dies, it undergoes a gravitational implosion and starts to collapse in on itself.
一颗恒星消亡时，会经历引力聚爆和坍缩。
If the star is massive enough, nothing can stop the collapse, and all that matter turns into a single point in space.
如果恒星足够大，其坍缩是不可阻挡的，整个恒星都会坍缩为宇宙中的一个点。
We call that point a singularity, and it has zero volume and basically infinite density.
这个点，我们称之为奇点。奇点的体积为零，密度无限大。
Like with basically everything involving infinity, it's hard to even imagine what that means.
就像所有与无限这个词搭边的事物一样，人类也很难想象奇点的具体含义。
But that's astrophysics for you, things get weird.
但天体物理学就是这样，不奇怪就不是天体物理学了。
And you might want to fasten your seatbelt, because they're about to get a whole lot weirder.
不过，从现在开始请系好你的腰带，我们要开车了，没有最奇怪，只有更奇怪。
A singularity isn't the same thing as a black hole, but it is what causes the black hole.
奇点和黑洞还不是一回事，因为黑洞是奇点演变来的。
The term black hole refers to everything inside the event horizon,
“黑洞”指的是所有视界里的所有事物，
the point where the singularity's gravitational pull becomes so strong that light can't escape.
在黑洞这个点上，奇点的强大引力让任何光都无法逃脱。
It's impossible to see anything inside it from the outside.
从外面完全不可能了解黑洞里面的情况。
And if you decided to go inside the event horizon to check out what's going on, you'd never get out again.
如果你想进入黑洞的视界里一探究竟，那你可能就再也出不来了。
So, sure, for a moment you'd be the only person in the universe to actually know what's happening down there,
也就是说有那么一瞬间，你是宇宙里唯一一个真正了解黑洞里面情况怎样的人，
but you'd never be able to tell anyone and you'd be stuck until you died.
但你却无法告知任何人。只能困在黑洞里等死。
In 1965, an astrophysicist named Roger Penrose demonstrated that all black holes must have singularities within them.
1965年，一位名为罗杰·彭罗斯的天体物理学家证明：所有黑洞里都有奇点。
Makes sense. But he couldn't prove that all singularities need to have a point-of-no-return event horizon, and therefore a black hole, surrounding them.
这一点虽然说得通，但罗杰无法证明所有奇点都需要有无归点的视界，因此也就无法证明奇点周围必有黑洞存在。
In other words, he couldn't prove that it was impossible for a singularity to be naked.
也就是说，罗杰无法证明奇点都不可能是裸奇点。
He was pretty sure naked singularities couldn't exist though, even if he couldn't mathematically prove it.
罗杰十分确信，裸奇点是不可能存在的，虽然他无法从数学的角度证明这一点。
Four years later, he coined what's known as the conjecture of cosmic censorship,
四年后，他创造了著名的宇宙监察假设。
which basically just says that it's impossible for a singularity to exist without a black hole around it.
该假设认为，奇点周围必有黑洞。
Again, he couldn't prove it, it was just a conjecture.
这个假设他也无法证明，也只是个假设。
But it was really hard to imagine how an infinitely dense point could exist without a black hole around it,
但很难想象一个密度无限大的点周围没有黑洞，
and all these decades later, many astrophysicists still subscribe to cosmic censorship. But not all of them.
所以几十年后的今天，很多天体物理学家依然支持宇宙监察假设，不过也有人不相信。
We've obviously never observed a naked singularity, but that doesn't mean it's impossible for them to exist.
人类确实未曾观测到裸奇点，但这并不意味着裸奇点就不存在。
This long-running debate actually led to one of many wagers Stephen Hawking has publicly made about astronomical discoveries.
对裸奇点是否存在的问题争论了许久后，史蒂芬·霍金关于天文学诸多发现的赌注里也多了一个与裸奇点有关的赌。
In the early 1990s, he bet Caltech's Kip Thorne and John Preskill that naked singularities can't exist.
上世纪90年代初期，霍金跟加州理工学院的基普·索恩和约翰·普雷斯基尔打赌说裸奇点并不存在。
The loser had to, quote reward the winner with clothing to cover the winner's nakedness which was definitely on-theme.
打赌输的一方必须“给赢家遮蔽裸体的衣服”，赌注可以说是非常切题了。
Months later, Hawking actually found mathematical evidence though not definitive proof that
几个月后，霍金发现了数学角度的证据，虽然不是铁证，
when a black hole finishes evaporating, it might leave behind a naked singularity.
黑洞一旦结束蒸发，就可能会留下裸奇点。
If the idea of a black hole evaporating sounds super strange well, it is. But it's one of the many quirks of quantum mechanics,
只不过就是黑洞会蒸发这件事听起来怪异至极，但这是量子力学众多怪异事件中的一个，
which predicts that a pair of particles can spontaneously pop into existence with one on either side of the event horizon.
量子力学预测，视界的任意一边只要有一个量子，就会自发形成另一个量子，凑成一对。
If the one outside has the right trajectory, it'll escape off into the universe, leaving the black hole with a teeny tiny little bit less mass.
如果视界外的量子有正确的轨道，那么这个量子就会逃向宇宙中，使黑洞减少一丢丢的重量。
But! Quirks of quantum mechanics didn't fall within the confines of the bet, so Hawking technically hadn't lost.
但是！量子力学的怪异之处并不在这个赌注的范畴内，所以严格来说，霍金并没有输。
He had to concede in 1997, though, when computer models found a special case for fine-tuned parameters that would produce a naked singularity from an imploding star.
不过，1997年，电脑模型发现，对恒星聚爆后的参数进行微调就可以产生裸奇点，这虽然是一种特殊情况，但霍金还是输了。
Basically, it's like trying to balance a sharpened pencil on the pointy end. Highly improbable, but not impossible.
这就好像试图在铅笔尖的那一端找到平衡一样，虽然不太可能，但也不是完全不可能。
Hawking made the most of his loss, though he gave Thorne and Preskill T-shirts featuring a woman in nothing but a towel,
霍金基本上算是兑现了自己的赌注，他给了索恩和普雷斯基尔两件T恤，衬衫上的女人只裹着一条毛巾，
along with the words Nature Abhors a Naked Singularity.
衬衫上写着大自然厌恶裸奇点。
So, simulations are able to suggest naked singularities might form if conditions are just right, but what about more general cases?
所以说，通过模拟手段，在条件适当的时候是可以产生裸奇点的，但一般情况下会产生裸奇点吗？
Well, researchers have found that if our universe had a different number of dimensions,
一些研究人员发现，如果宇宙的维度数量与现在不同，
or was shaped differently than it is, then yes it could form naked singularities.
或者说宇宙的形态与现在不同，确实会有许多裸奇点。
But all this could mean that naked singularities only work on paper, not in practice.
但这也只能说明，裸奇点只能是纸上谈兵的东西，无法付诸实践。
We're kinda stuck with the universe we've got.
对于现在的宇宙，我们陷入了死循环。
If by chance we actually learn of a real naked singularity floating around out there in the cosmos, though, it could change our understanding of the universe.
如果我们真能偶然得知宇宙间存在某个真实漂浮的奇点，那将会改变我们对宇宙的认知。
Mainly because we'd be able to study something that's governed by both quantum mechanics,
这主要是因为，我们能研究的东西必须符合量子力学这种微观科学的原理，
the science of the very small and general relativity, the science of the very massive.
也要符合广义相对论这个宏观科学的原理。
As it stands, these two theories work almost perfectly when you're using each of them on their own, but they don't play well together.
但现实是，这两种科学理论虽然都可以自圆其说，但却无法彼此配合。
When you try to apply them both at the same time, like when something is both super duper massive and super duper tiny,
如果想同时应用这两种理论，比如将它们用在既无限大又无限小的事物上，
basically, a singularity they spit out nonsense answers.
符合这种条件的基本上就只有奇点了，就会产生十分荒谬的结果。
But being able to directly observe a singularity would give us the data to either unite them, or scrap them for a different theory entirely.
但如果我们能直接观测奇点，就能获得数据，并据此决定是将它们合二为一，还是彻底分割为完全不同的理论。
A unified theory of the universe would do more than just reveal the secrets hiding in black holes.
宇宙的统一理论不仅能揭示黑洞中隐藏的秘密。
Right now, anything that happened before 10 to the negative 43rd seconds after the Big Bang is a big mystery
目前，宇宙大爆炸后-43秒至10秒间发生的事到现在还是一个巨大的谜团，
because both quantum mechanics and general relativity would apply to it.
因为用量子力学和广义相对论都说得通。
That's such a tiny fraction of time that you might think it wouldn't really matter anyway, but, like, those were the very first moments of our universe.
这段时间太短，所以你可能认为它并不重要，但这段时间确是宇宙最初的时段。
In other words, for being infinitely tiny, naked singularities are a pretty big deal.
与此相似，裸奇点虽然无限小，但却十分重要。
If you're interested in diving further into singularities, not literally, SciShow's sponsor, Brilliant has a lesson in their Astronomy unit about black holes
如果你想进一步了解奇点，可以登录《太空科学秀》赞助商Brilliant的网站，他们天文学的单元有一节课与黑洞有关，
that walks you through the escape speed, the Schwarzschild radius, and how we can detect black holes using gamma ray radiation and accretion disks.
会具体讲解逃逸速度、施瓦茨席尔德半径、如何通过Y射线照射和吸积盘来探测黑洞的存在。
Let's see how I do. Well, hello! And welcome to just outside the event horizon of our awesome black hole here.
我给大家演示一下我本人的学习过程，欢迎大家回到黑洞的视界外。
We're going to dive into the Brilliant.org lesson about black holes.
现在，我们要在Brilliant.org上学习与黑洞有关的知识。
And like with all Brilliant.org lessons it starts with some basic information about black holes in general,
跟Brilliant.org上的所有课程一样，这节课也会先从总体上介绍一些与黑洞有关的基本知识，
how they differ from other cosmic situations, and then we dive into some more detailed information.
比如黑洞与其他宇宙现象的区别，然后才会去了解更具体的知识。
For example this first question asks us about gravitational potential energy of an object on the surface.
比如，第一个问题与物体在地球表面的重力势能有关。
Whether that would be near the surface of a black hole or, as this questions starts us very simply, is the surface of the earth.
是在黑洞表面的附近呢，还是就在地球的表面那样简单呢？
So then we get our basic equation and then it asks us a clear question.
我们得到了基本方程之后，然后又弹出一个问题：
If the radius of Earth were smaller and the earth was denser, what would happen to potential energy?
如果地球半径缩短，地球密度变大，那么势能会有什么变化呢？
And so my guess, don't judge me if I get it wrong, would be that your potential energy would be lower.
那我就猜一下，错了不管哦！我猜势能会减小。
So I can click on that answer, and I nailed it!
于是我就选出答案，然后就完成了！
And we just continue on from here learning all sorts of awesome stuff.
按照这种方法继续往下，就能学到各种各样的知识。
And just so you know the first 200 people that sign up at brilliant.org/scishowspace will get 20% off their annual subscription AND support SciShow Space so thanks!
还有哦，你们可能已经知道，前200位在brilliant.org/scishowspace注册的用户可以减免20%的订阅费，同时也是对我们栏目的鼎力支持，我们将不胜感激！
