Well, this is scary enough. They have an even more powerful and dark property: they might delete the universe itself.

這聽起來似乎夠可怕了， 但它們還有更強大、更深沉的特性: 它們可能會吞噬宇宙本身

Black holes in a nutshell

[開場音樂~]

A black hole appears when an extraordinary amount of matter is concentrated in a tiny space.

我們來簡談黑洞吧

At their center, gravity is almost infinitely strong and whatever gets too

當極大量的物質被壓縮到極小的空間時， 黑洞就會出現

close is ripped into its elementary particles.

黑洞中心的引力幾乎是無限強大的，所以無論是什麼東西，只要太靠近它，都會被撕成基本粒子

Not even light can escape black holes, and so we perceive them as spheres of blackness.

就連光也無法逃不出黑洞， 所以在我們看來它們是顆黑暗的球體

If you were to fall into a black hole, nothing bad would happen until well after you crossed its outer border: the event horizon.

如果你掉進黑洞裏，還不會發生什麼壞事，直到你越過了它的外邊界──事件視界

You can imagine this as swimming in a river that ends in an enormous waterfall.

你可以想像成你在河裡游泳，而盡頭是一座巨大的瀑布

As you float along, imperceptibly, the stream gets faster and faster, even if you can't see the waterfall yet.

當你漂浮在水上時，即使還看不見瀑布， 但不知不覺地水流得越來越快

You could swim to safety, until without even noticing it, you cross the point of no return.

你還是可以游回安全水域中， 直到在沒有察覺的情況下，你越過一條無法折返的界線

No matter how fast you try to swim now, the stream will pull you towards certain death.

這時不管你游得有多快，水流最終還是會把你推向死亡

Nothing can escape a black hole waterfall once it gets too close.

任何東西一旦過於靠近，就不可能逃脫黑洞的瀑布

This border completely separates black holes from the rest of the universe: we can't access them unless we're willing to never return.

這個界線區隔了宇宙和黑洞， 除非我們沒有要折返的意圖，不然實在到不了黑洞

So there's no way of telling what's really going on inside black holes,

所以其實我們無法知道黑洞裡到底發生了什麼

but we have a few ideas about what's going on right at their very edges.

不過，對於黑洞邊界正在發生什麼事， 我們倒是有一些想法

Black holes radiate their mass away, like a hot pot on a stove losing its water as steam.

黑洞會以輻射的型態釋放它的質量， 就像放在爐子上的火鍋，以蒸發水的方式散發熱能

This is called Hawking radiation.

這就是所謂的"霍金輻射"

Black holes constantly lose an extremely tiny amount of their mass,

黑洞不斷地失去其極小部分的質量

a process that's unbelievably slow.

而這個過程是非常緩慢的

It will take a black hole with a mass of our sun 10,000 billion billion billion billion billion billion years to lose 0.0000001% of its mass.

如果有個跟太陽一樣質量的黑洞，大概只需要經過10^58年就可以散去0.0000001%的質量了呢~

This is happening constantly and unstoppably, and as it goes on it speeds up more and more.

這個過程會一直不間斷的持續下去， 而且速度將會越來越快

In the far far future when the last star in the universe has been dead for trillions of years,

在很遠很遠的將來， 當宇宙中的最後一顆星星已經死了萬億年之後

black holes will become tinier and tinier until they evaporate and disappear, leaving behind just a bit of radiation.

黑洞將變得越來越小， 直到它們蒸發、消失，只留下一點點的輻射能

But this is a problem, because in the process of disappearing black holes might delete something fundamental: information.

不過這會是個問題，因為在黑洞消失的過程中， 可能會刪除一些宇宙的基礎：訊息（或稱"資訊"､"資料"）

2 - What is information?

二、什麼是"訊息"？

Information is nothing tangible. It's typically understood as a property of the arrangement of particles. What does this mean?

"訊息"是無形的存在， 而它通常被理解為"粒子排列的特性"，這是什麼意思呢？

Imagine a bunch of carbon atoms. Arrange them in a certain way and you get coal.

想像有一束碳原子，以某種方式排列它們，你會得到煤

Arrange them in a different way, and you get a diamond.

以另外一種方式排列它們，你則會得到鑽石

The atoms are the same, what changes is the information. If we make this more complex and add in a few more atoms,

這些原子的本質都一樣，改變的東西是"訊息"。 如果我們把這弄得更複雜，並加入更多種類的原子......

we get a banana.

......那我們會得到一個香蕉~

Change the arrangement of the atoms, and we get a squirrel.

改變原子的排序，那我們得到一隻松鼠~

The basic building blocks of everything in the universe are the same,

構成這個宇宙所有東西的基本建構物質都是一樣的， 不管是鳥、石頭、還是一杯咖啡，都一樣

and don't care if they're part of a bird or a rock or a cup of coffee.

如果沒有"訊息"，宇宙中的一切將會毫無分別

Without information everything in the universe would be the same.

而根據量子力學理論，"訊息"是無法被摧毀的

According to the theory of quantum mechanics information is indestructible.

它可能會改變形狀

It might change shape,

但它永遠不會消失。 比如說，如果你燒掉一張紙，你會得到灰

but it can never be lost: for example if you burn a piece of paper, you get ash.

基本上那些灰不會再變回紙了

That ash will never become paper again.

但是，如果你能仔細地收集那些灰裡的每一個碳原子， 並準確測出從火中散發的煙霧和熱能的性質， 理論上你能把紙重建

But, if you were able to carefully collect every single carbon atom in the ash, and measured the exact properties of the smoke and heat

那張紙的"訊息"一直都存在於宇宙之中，它並沒有消失

radiating from the fire, you could, in theory reconstruct the paper.

它只是變的很難"讀取"

The information of the paper is still in the universe. It's not lost,

如果你能以某種方式去測量宇宙中的每一顆原子、粒子和輻射波

it's just hard to read.

你就能看見並追蹤每一個"訊息"

If you could somehow measure every single atom and particle and wave of radiation in the universe,

理論上你能看見宇宙的整體歷史， 從現在一直回溯至宇宙大霹靂

you could see and track every bit of information there is.

而在大霹靂這個點， 黑洞將會成為我們無法再往前回溯的原因

Hypothetically, you could see the entire history of the universe right back to the Big Bang.

"訊息"能告訴我們， 事物如何開始有了區別、而這事物的前身又是什麼

And here black holes trip us up.

黑洞卻反其道而行：它們讓不同的事物變成一樣的東西。它們破壞"訊息"

Information tells us how things are different from each other and what used to be what.

這就造成了"訊息悖論"，而這是個很嚴重的問題

Black holes do the opposite: they take different things and make them the same. They destroy information.

~~~訊息悖論~~~

This creates the information paradox, and this is a serious problem.

我們目前所有的物理學定律都建立在一個基礎上： "訊息"不會消失

The information paradox

存在？不存在？

It's fundamental for all our laws of physics that information can never be lost.

如果沒有"訊息"，則一切都是相對的

Existing, not existing. Without information, everything is relative.

如果我們想要理解"現實"，那就需要絕對性的定義

When it comes to our understanding of reality, we need absolutes.

我們如何解決這個矛盾(悖論)？

How could we solve this paradox?

有幾種可能性：

There are a few possibilities.

一）訊息不見啦~

1) Information is lost.

而且是無可返回的不見啦~

Irretrievably and forever.

這表示，我們要否決掉所有的物理學定律， 然後丟掉一堆至今運做的很不錯的理論，從頭開始做起

This means we have to nix all our laws of physics, throwing out a lot of stuff

新的物理學定律會長什麼樣子？對我們這意味著什麼？ 沒人知道

that's worked very well so far and to start from scratch

這聽起來好像有點可怕，不過好像也讓人有點興奮

What those new laws of physics would look like, or what that means for us, nobody knows.

二）訊息被隱藏啦~

This is a little frightening, but also kind of exciting.

也許黑洞的一小部分分裂了出來，形成一個"嬰兒宇宙"

2) Information is hidden.

"訊息"將被轉移到這個又新又奇怪的地方， 不過我們既沒辦法觀測，也沒辦法與之交流

Maybe a little part of the black hole splits off and forms a baby universe.

嚴格來說，"訊息"沒有不見

The information would be transferred into this new weird place, where we could never observe or interact with it,

這就好像你有一個你永遠沒辦法讀取， 而且裡面存著你跟你家人照片的壞掉硬碟

but technically it would not be lost.

沒被刪掉聽起來是很好啦，可是根本沒屁用啊

It's like having a broken hard drive with all your family photos, that you could never access.

也有可能，黑洞在生命周期結束後並不會完全地消失，

Sure, it's nice that they've not been deleted, but also not very helpful.

它可能會留下一小塊"訊息鑽石"

Or maybe black holes don't disappear completely after the end of their life cycles,

就像一輛塞滿著無限"資訊小丑"的小丑車一樣

but a little piece is left, an information diamond.

但是，還有第三個選項

like a clown car filled with an infinite amount of information clowns.

訊息很安全啦~，沒有不見也沒有被藏起來

But there's a third option:

搞不好我們看待這整件事的方法都錯了

Information is safe after all, not lost or hidden.

我們知道黑洞會困住"訊息"，然後可能隨後就刪掉了。 不過，我們沒想到黑洞在此同時可能還會做什麼

Perhaps we've just been looking at this whole thing the wrong way.

黑洞把自己的"訊息"儲存在哪裡呢？

We know that black holes trap information and might delete it later, but we never thought about what they do with it in the meantime.

~~宇宙收納~~

Where do black holes store their information?

讓我們用髒衣服創造一個黑洞吧

Cosmic housekeeping

首先，我們用裝了髒衣服的洗衣籃塞滿房間。 你想儲藏的髒衣服越多，房間裡的洗衣籃就越多

Let's create a black hole with dirty laundry.

到了某個時刻每個洗衣籃都滿了，房間也被堆滿了， 連支襪子都沒辦法再塞進去

First, we fill up a room with laundry baskets: the more laundry you want to store, the more baskets you put in the room.

這個房間目前處於全滿狀態

But at some point every single basket is full, and the room is completely stacked, not a single extra sock fits in.

不過如果我們用很多能量硬塞一支襪子進去， 就會導致這個房間崩塌成一個黑洞

The room is at maximum capacity.

但是房間本身的容量並沒有改變，要放入更多東西或是"資訊"還是不可能的

But if we still squeeze the sock in with a lot of energy and violence, the room collapses in on itself and forms a black hole.

所以如果我們再丟更多髒衣服進去會怎麼樣呢？

But the capacity of the room itself has not changed, fitting in more stuff or information is still impossible.

房間本身會自己變的大一點， 為了新進的資訊而騰出空間

So what happens if we throw more laundry into it?

原來黑洞每吸進一點"訊息"， 它的表面就會成長一點點

The room itself gets a little bit bigger to make space for the new information.

簡而言之，"訊息"越多，表面積也就越大

It turns out a black hole grows its surface by a tiny pixel for each bit of information we throw into it.

"訊息"被呈現在表面上。 就如同我們丟一塊石頭到池塘裡會發生的事一樣

In a nutshell, more information means more surface area.

石頭沉到底部之後，我們就看不到它了

The information gets painted on the surface, similar to what happens when we throw a stone into a pond.

不過我們可以從池塘表面的漣漪知道有東西掉進去了

After the stone sinks to the bottom we can't see it anymore,

即使是最小的黑洞，其表面所儲存的"訊息"也比人類歷史上產生的所有數據還多

but we can tell that something went in from the ripples on the surface of the pond.

他們靠把"訊息"儲存在一個小到令人難以置信的像素上來達到這點

Even the smallest black hole can store more information on its surface than all the data ever produced in human history.

黑洞，是一個究極的硬碟啊

They do this by storing information in a type of pixel that is unbelievably tiny.

這有點像是把一本平裝書轉成電子書， 這兩個東西看似完全不同

Black holes are the ultimate hard drive.

不過它們的內容物是相同的， 只是用了另一種編碼和記憶的方式

This is a bit like taking a paper back, and turning it into an e-book, two things that look completely different.

黑洞吞噬了恆星、行星， 這有點像是把整個圖書館裡的書都轉成電子檔

But their content is the same -- it's just encoded and memorized in another way.

這被叫做"全像原理"，不過如果這是對的， 那我們所有對於宇宙的認知就是錯的

Black holes swallowing stars and planets is a bit like transferring a whole library onto an e-reader.

宇宙是個全像投影圖

This solution is called the holographic principle, but if it's correct then everything we thought we knew about the universe is wrong.

如果"訊息"真的是被儲存在黑洞邊界， 那霍金輻射便有可能記住並帶走編碼在那裡的"訊息"

The universe is a hologram

所以就算黑洞完全消逝了，資訊也不會消失

If information is actually stored on the boundary of a black hole, the Hawking radiation has a chance of learning about the information

而且我們的物理學也不需要再重新來一遍， 訊息悖論被解決了！

encoded there, and can carry it away.

不過我們還是要從根本上改變對現實的認識

So, information is not lost when black holes fade away,

如果落入黑洞的一切都被儲存在它的事件視界， 這基本上意謂著三維的事物是在一個平面上進行編碼的

and we do not need to redo physics: the information paradox is resolved.

我們幫這取了個名字：全像投影圖

But we still have to change our understanding of reality in a fundamental way.

全像圖就像一個3D照片： 編碼著三維圖像在其中的扁平塑膠片

If everything that falls into the black hole is stored on its event horizon, that basically means that three-dimensional stuff is encoded on a flat surface.

黑洞就像一個全像圖， 因為它裡頭的一切都編碼在事件視界上

We have a name for this: a hologram.

在黑洞裡的人會感覺自己活在平常的三維空間中

A hologram is like a 3D photo, a flat piece of plastic that encodes a three-dimensional image.

不過對在外側的我們而言， 他們只不過是在黑洞表面上的扁平圖片罷了

A black hole is like a hologram, because everything inside it is encoded on its event horizon.

這結果聽起來很違反直覺啊，不過請等我一下

A person inside a black hole will experience their usual three-dimensional life.

黑洞是個極端的物件， 不過它們仍然遵守與其他事物相同的規則

but for us on the outside they are flattened images on the surface of the black hole.

所以如果這種2D和3D之間瘋狂的二相性適用於黑洞， 那它也可能同樣運作於你存在的這整個宇宙之間

The consequence of this is counterintuitive, but stay with us for a moment.

由於黑洞內部的人不會意識到， 其實他們被編碼在一個扁平表面上

Black holes are very extreme objects, but they're still bound to the same rules as everything else.

所以我們可能共享相同的命運， 你真的有可能會被拉伸在宇宙盡頭的平台上呢

So if this crazy duality between 2D and 3D works for black holes, then it might work for the whole universe, and you in it.

在這理論背後的科學極其複雜、也相當奇異。 它用微型宇宙來模擬，並加入了弦理論和一大堆質量......

Since a person inside a black hole would not realize that they're encoded on a flat surface,

我們會在另一部影片中，對這部分多加討論

we might share the same fate: you really might be stretched over a flat screen at the end of the universe.

無論宇宙真正的樣貌是什麼

The science behind this is complicated and really weird, with toy universes to play with, string theory and a lot of maths.

我們只知道它是奇怪而複雜的， 而且我們必須多加鑽研物理來瞭解它

We'll talk about this more in another video.

不過黑洞可能就是瞭解現實本質的關鍵

Regardless of what the true nature of the universe really is, we just know that it's strange and complicated,

這部影片是由瑞士國家科學基金會支持， 並靠著 Alessandro Sfondrini 的科學建議而實現的

and we have to do a lot more physics to understand it.

繁體中文譯：ScTruF 校對: Vamesix

But black holes might be key to understanding the nature of reality itself.

This video was supported by the Swiss National Science Foundation, and realized with the scientific advice of Alessandro Sfondrini.