Once you go in, you don't go out.

一旦你進去了，你就不會再出來了。

But beginning with the work of Stephen hawking we realize that.

但從斯蒂芬-霍金的作品開始，我們意識到。

Don't worry dude you're in this episode a lot.

別擔心，夥計，你在這一集裡有很多。

We realize that black holes emit radiation they actually glow just a little bit and they eventually dissolve completely disappearing.

我們意識到，黑洞會發出輻射，它們實際上只是發出一點光芒，最終會完全溶解消失。

And this opens up a nasty paradox called the black hole information paradox.

這就開啟了一個討厭的悖論，叫做黑洞資訊悖論。

What happens to all the information that flows into a black hole after it disappears?

黑洞消失後，所有流入黑洞的資訊會發生什麼？

The full answer relies on a complete description of quantum gravity which which we don't have.

完整的答案有賴於對量子引力的完整描述，而我們沒有這種描述。

Yeah, okay let's take a step back in Einstein's theory of relativity.

是的，好吧，讓我們在愛因斯坦的相對論中退一步。

Black holes are extraordinarily simple objects.

黑洞是特別簡單的物體。

You just need three.

你只需要三個。

Only three numbers to completely describe any black hole.

只有三個數字可以完全描述任何黑洞。

You need to know its mass, its electric charge and its spin and that's it.

你需要知道它的品質，它的電荷和它的旋轉，僅此而已。

And then the black holes themselves are extraordinarily simple.

然後，黑洞本身也是異常簡單的。

There's a singularity at the center which is a point of infinite density and also the subject of another episode and then it's surrounded by an event horizon.

中心有一個奇點，這是一個無限密度的點，也是另一集的主題，然後它被一個事件視界所包圍。

That is the boundary, the entrance to the roach motel.

那是邊界，是蟑螂旅館的入口。

But that event horizon is even more boring than you think it might be.

但是那個事件視界比你想象的還要無聊。

Take a look at this water.

看一看這水。

Where is the point of no return.

哪裡是不歸路。

It's not the waterfall itself.

這不是瀑布本身的問題。

It's somewhere upriver.

它在上游的某個地方。

There's a place on the river where the flow is too strong for you to be able to fight against the current that is the event horizon.

在河上有一個地方，水流太強，你無法與水流抗衡，這就是事件視界。

That is the point of no return.

這就是不歸路。

And this shows us how boring event horizons really are.

而這讓我們看到，事件的視野到底有多無聊。

They don't look any different from any other part of the river, you only discover them when you try to escape.

它們看起來與河流的其他部分沒有任何不同，你只有在試圖逃跑時才發現它們。

But Stephen Hawking found that event horizons are anything but boring.

但斯蒂芬-霍金髮現，事件視界並不無聊。

There's a weird interaction happening there between the event horizon itself and the quantum fields that surround it in this interaction gives rise to the emission of particles particles that have a temperature black holes.

在事件視界本身和圍繞它的量子場之間發生了一種奇怪的互動，在這種互動中產生了具有黑洞溫度的粒子的發射。

Whoa!

哇!

And that's really messed up.

而這真的很混亂。

So let's go to the chalkboard to check this out.

是以，讓我們去黑板上看看這個。

Stephen Hawking's result was extraordinary and honestly counterintuitive.

斯蒂芬-霍金的結果是非同尋常的，說實話是反直覺的。

Who knew that that black holes, the ultimate bottomless pits of destruction would glow would have a temperature.

誰知道黑洞，這個毀滅的終極無底洞會發光會有溫度。

And this temperature is something that we can, if we can calculate Hawking's formula for the temperature of a black hole is simply temperature is equal to the reduced plank's constant H, which is Planck's constant, divided by two pi times the speed of light cubed, divided by eight pi.

而這個溫度是我們可以的，如果我們可以計算出霍金的黑洞溫度公式，簡單來說就是溫度等於縮小的普朗克常數H，也就是普朗克常數，除以2π乘以光速的立方，除以8π。

Newton's gravitational constant times the bolts men, constant times the mass of the black hole.

牛頓的引力常數乘以螺栓人，常數乘以黑洞的品質。

This is telling us that the temperature of a black hole is incredibly small because the mass of a black hole, even the smallest black holes have a massive a few times that of the sun.

這就告訴我們，黑洞的溫度小得驚人，因為黑洞的品質，即使是最小的黑洞也有幾倍於太陽的品質。

Makes this a very very big number.

使得這是一個非常非常大的數字。

Which makes temperature a very, very small numbers.

這使得溫度成為一個非常、非常小的數字。

So this is incredibly, incredibly small.

是以，這是令人難以置信的，令人難以置信的小。

We're talking a typical black hole emitting, you know, like one or 2 photons a year.

我們說的是一個典型的黑洞，你知道的，一年發射一到兩個光子。

But it's not zero.

但這並不是零。

Now black holes emit radiation through this this crazy complex quantum mechanical process.

現在，黑洞通過這個瘋狂複雜的量子力學過程發出輻射。

Any kind of radiation has a has a spectrum has a structure.

任何一種輻射都有一個光譜，有一個結構。

But to describe the radiation emitted by a black hole, I need some sort of inspiration.

但要描述黑洞發出的輻射，我需要某種靈感。

A lightbulb moment, if you will.

如果你願意的話，這是一個閃光的時刻。

Thank you.

謝謝你。

All right, This is an old school incandescent light bulb and the kind of radiation the spectrum of radiation emitted by this light bulb is something we call black body radiation.

好吧，這是一個老式的白熾燈泡，這個燈泡發出的那種輻射的光譜是我們稱之為黑體輻射的東西。

Now, lightbulbs aren't the only thing in the universe to have blackbody spectrum of human bodies emit radiation with a similar spectrum of the sun, emits radiation with the same spectrum.

現在，燈泡並不是宇宙中唯一具有黑體光譜的東西，人體發出的輻射具有類似太陽的光譜，發出的輻射具有相同的光譜。

And so do black holes.

黑洞也是如此。

Let's say we have a very cold object.

比方說，我們有一個非常冷的物體。

Very cold objects have a blackbody spectrum of a flux versus wavelength.

非常冷的物體有一個黑體光譜，即通量與波長的關係。

That looks something like this.

這看起來像這樣。

Very hot objects have a similar kind of spectrum, but it's shaped more like this.

非常熱的物體有一種類似的光譜，但它的形狀更像這樣。

It's it's pickier and then it goes down like this.

這是它比較挑剔，然後就這樣下去了。

Any object in the universe that emits as a black body radiator.

宇宙中任何以黑體輻射方式發射的物體。

We'll have something looking like these curves, including black holes.

我們會有一些看起來像這些曲線的東西，包括黑洞。

That's one of the most remarkable things about Hawking's result is how simple the radiation emitted by black holes really is.

這是霍金成果中最了不起的事情之一，即黑洞發出的輻射到底有多簡單。

It's this crazy complex quantum mechanical process that leads to a simple equation for the temperature And then a well known spectrum that we've we've known about for over a century.

這是一個瘋狂的複雜的量子力學過程，導致了一個簡單的溫度方程，然後是一個眾所周知的光譜，我們已經知道了一個多世紀。

But that simplicity makes black holes even more confusing because this is the exact place where the paradox comes in?

但這種簡單性使黑洞更加令人困惑，因為這正是悖論出現的地方？

Because the blackbody radiation emitted by a black hole doesn't carry any information.

因為黑洞發出的黑體輻射並不攜帶任何資訊。

It's very boring actually.

實際上，這非常無聊。

So let's say you you make one black hole made out of, I don't know a potato.

是以，假設你做了一個黑洞，由我不知道的一個洋芋製成。

All right, and you make another black hole made out of a plant.

好吧，你再做一個用植物做成的黑洞。

Yeah.

是的。

So we've got two black holes, one is made out of potatoes and one is made out of plants, a lot of potatoes and a lot of plants.

所以我們有兩個黑洞，一個是用洋芋做的，一個是用植物做的，有很多洋芋和很多植物。

But you get the idea.

但你會明白這個道理。

There's a lot of information in this plant and in this potato and it's locked up in the black hole.

這個植物和這個洋芋中有很多資訊，它們被鎖在黑洞中。

But then the black hole starts radiating and they have the exact same mass.

但隨後黑洞開始輻射，它們的品質完全相同。

They have the exact same temperature.

它們的溫度完全相同。

There's exact same blackbody radiation.

有完全相同的黑體輻射。

There's no information carried away.

沒有任何資訊被帶走。

I don't know which one is the potato black hole and which one is the plant black hole.

我不知道哪一個是洋芋黑洞，哪一個是植物黑洞。

But as they radiate, they lose mass and eventually they disappear.

但隨著他們的輻射，他們失去了品質，最終他們消失了。

So where did the information go?

那麼，這些資訊到哪裡去了？

What happened to that?

發生了什麼事？

This is the paradox.

這就是矛盾之處。

So let's talk to an expert to dig into this mystery a little bit more.

是以，讓我們與一位專家談談，進一步挖掘這個謎團。

I am dr moya McTeer, I am an astrophysicist of folklorist and the science communicator.

我是Moya McTeer博士，我是一位天體物理學家、民俗學家和科學傳播者。

Well, let's talk about space and we're talking about black holes, the universe makes stars and some stars turn into black holes.

好吧，讓我們來談談空間，我們正在談論黑洞，宇宙製造恆星，一些恆星變成了黑洞。

How does that happen?

那是怎麼發生的呢？

How do you go from this giant ball of radiation and light and warmth to a black hole black holes can form in a few different ways, astronomers are still trying to figure out how the very first early big black holes formed, we call these primordial black holes.

你如何從這個巨大的輻射和光和溫暖的球變成一個黑洞黑洞可以通過幾種不同的方式形成，天文學家仍在試圖弄清楚最早期的大黑洞是如何形成的，我們稱之為原始黑洞。

But the most common way for black holes to form is through the life cycle of stars.

但是黑洞形成的最常見方式是通過恆星的生命週期。

So you have a star that's massive enough, let's say it has to be about 40 times more massive than our sun by the time it runs out of all of the hydrogen in its core, something called hydrostatic equilibrium breaks.

所以你有一顆品質足夠大的恆星，比方說它的品質必須是我們太陽的40倍，當它耗盡核心中所有的氫氣時，一種叫做靜水平衡的東西就會打破。

So the way that stars work is that they're constantly imbalance between gravity crushing in and the pressure that you get when you have nuclear fusion pushing out and when you stop using hydrogen in your core, you lose the outward pressure so gravity forces the star to collapse in on itself.

是以，恆星的工作方式是，它們在重力的擠壓和你有核聚變時得到的壓力之間不斷失衡，當你停止使用核心中的氫氣時，你失去了向外的壓力，所以重力迫使恆星向自身坍縮。

And then there's this rebounding effect that creates a supernova explosion.

然後有這種反彈效應，形成超新星爆炸。

So in the explosion a lot of the material from the star gets flung out from the system.

是以，在爆炸中，大量來自恆星的物質被從系統中甩出。

But what's left if it's dense enough or if it's massive enough is a very dense black hole.

但是，如果它的密度足夠大，或者它的品質足夠大，剩下的就是一個非常密集的黑洞。

These are small black holes.

這些是小黑洞。

They're called stellar mass black holes only a few times more massive than our sun.

它們被稱為恆星品質的黑洞，品質只比我們的太陽大幾倍。

But if you get enough of them together, then they can grow into a bigger black hole.

但是，如果你有足夠多的人在一起，那麼他們可以成長為一個更大的黑洞。

How many black holes are we talking about in a galaxy?

我們談論的是一個星系中有多少個黑洞？

12, maybe 10.

12，也許是10。

We have one supermassive black hole in the Milky Way galaxy, but there are tens of thousands of these smaller stellar mass black holes in the Milky Way alone and there are hundreds of billions of Galaxies.

我們在銀河系有一個超大品質的黑洞，但僅在銀河系就有數以萬計的這種較小的恆星品質的黑洞，而且有數千億個銀河系。

So there are lots of black holes out there in the universe.

是以，宇宙中存在著許多黑洞。

You mentioned the supermassive black hole in the center of the Milky Way, How do you get something to be super massive?

你提到了銀河系中心的超大品質黑洞，你是如何讓一個東西成為超大品質的？

And I think in a lot of space contexts, astronomers are still trying to figure out how these really massive black holes form, but we are pretty sure that at least regular supermassive black holes, not these like hyper massive ones that they form through galactic collisions because a lot of Galaxies, most Galaxies have black holes at their centers and that's just another effect of gravity.

我認為在很多空間背景下，天文學家仍在試圖弄清楚這些真正巨大的黑洞是如何形成的，但我們非常肯定，至少常規的超大品質黑洞，而不是這些像超大品質的黑洞，它們是通過星系碰撞形成的，因為很多星系，大多數星系的中心都有黑洞，這只是重力的另一種影響。

This really heavy thing is going to sink towards the center of the galaxy and when these Galaxies collide, so do their black holes after many millions of years of spinning in towards each other.

這個非常重的東西將向星系中心沉沒，當這些星系發生碰撞時，它們的黑洞在經過數百萬年的相互旋轉後也會發生碰撞。

When you get all of these black holes colliding, then their masses add up.

當你得到所有這些黑洞的碰撞，那麼它們的品質就會增加。

So you get a super massive one in the center.

所以你在中間得到一個超級巨大的。

These black holes, they just sit there minding their own business and they don't do anything else, right?

這些黑洞，它們只是坐在那裡管好自己的事情，它們不做其他事情，對嗎？

Oh, I wish well it actually is a common misconception that black holes suck things into them and they do have very strong gravitational pools but they aren't like vacuums actually suctioning stuff in.

哦，我希望如此，實際上這是一個常見的誤解，認為黑洞會把東西吸進去，它們確實有非常強大的引力池，但它們並不像真空吸塵器那樣真正把東西吸進去。

It's just a gravity well it is a pit for stuff to fall into.

這只是一個重力井，它是一個讓東西掉進去的坑。

If we look at the anatomy of a black hole, there's the black hole in the center and the edge of the black hole was called the event horizon after the event horizon.

如果我們看一下黑洞的解剖結構，中心是黑洞，黑洞的邊緣在事件視界之後被稱為事件視界。

If the black hole is massive enough and active enough, it has something called an accretion disk.

如果黑洞的品質足夠大，而且足夠活躍，它就會有一個叫做吸積盤的東西。

So this is the disk of material around the black hole that it's eating, its material that has been gravitationally attracted to the black hole and is actively in the process of spinning into this gravity pit.

所以這是黑洞周圍被它吃掉的物質盤，它的物質被黑洞的引力所吸引，正在積極地旋轉到這個引力坑中。

Sometimes there's enough friction and heat in that accretion disc that it lights up so we can see it.

有時，在那個吸積盤中有足夠的摩擦和熱量，它就會發光，所以我們可以看到它。

That's how we study a lot of black holes or we study their gravitational effect on things around it, like the stars that are orbiting it.

這就是我們研究很多黑洞的方法，或者說我們研究它們對周圍事物的引力影響，比如圍繞它運行的恆星。

One of the things we're exploring in this episode is hawking radiation.

在這一集裡，我們要探討的一個問題是鷹擊長空的輻射。

Can you just talk about hawking radiation and how annoying it is?

你能不能只說說霍金輻射和它有多煩人？

Yes, I can.

是的，我可以。

So we say that black holes are so dense that nothing can escape them unless they're traveling faster than the speed of light.

所以我們說，黑洞的密度很大，除非它們的速度超過光速，否則沒有任何東西可以逃離它們。

But that creates this this paradox because black holes have energy and they can dissipate that energy but if something can escape a black hole, how can it possibly dissipate this energy.

但這就產生了這個悖論，因為黑洞有能量，它們可以消散這些能量，但如果有東西可以逃離黑洞，它怎麼可能消散這些能量。

Stephen hawking came up with this hypothesis for radiation that gets trapped basically on opposite sides of the event horizon.

斯蒂芬-霍金提出了這樣的假設，即輻射基本上被困在事件視界的兩邊。

Some gets sucked in some dozen.

有些人被吸進去了，有些人被打進去了。

The stuff that doesn't get sucked in can be radiated away as energy as this Hawking radiation.

沒有被吸進去的東西可以作為這種霍金輻射的能量被輻射出去。

Yeah, I've been thinking a lot about the long term end of the universe and one of the potential ways that the universe could end is in the big freeze.

是的，我一直在思考宇宙的長期終結問題，而宇宙終結的潛在方式之一就是大凍結。

This is the scenario where the universe keeps expanding forever long enough that all of the gas gets made into stars and then all of those stars die and they cool off and eventually many, many trillions of years from now.

這是一種設想，即宇宙永遠保持膨脹，足夠長的時間，所有的氣體被製成恆星，然後所有這些恆星死亡，它們冷卻，最終從現在起很多很多萬億年。

The only thing left in the universe is black holes after all of the stars have pulled down to dark chunks of rock.

宇宙中唯一剩下的是黑洞，在所有的恆星都拉下來變成黑暗的岩石塊之後。

So some scientists have tried to figure out what happens after that.

是以，一些科學家試圖弄清楚之後會發生什麼。

How do the black holes lose energy?

黑洞是如何失去能量的？

Because the only way for the universe to really be dead is for there to be no energy in it.

因為宇宙真正死亡的唯一途徑是其中沒有能量。

So one way that black holes can lose their energy is through this talking radiation and it would take many, many billions of years.

是以，黑洞失去能量的一種方式是通過這種會說話的輻射，而這將需要許多、許多億年。

We're a single black hole to lose all of its energy through Hawking radiation.

我們是一個單一的黑洞，通過霍金輻射失去其所有的能量。

But it is theoretically possible.

但理論上是可能的。

So the ultimate fate of the universe rests in understanding Hawking radiation.

是以，宇宙的最終命運在於瞭解霍金輻射。

The ultimate fate of the universe in this one potential scenario.

在這一個潛在的情況下，宇宙的最終命運。

Thank you moya Yeah, thank you to achieve his result.

謝謝你，莫亞 是的，謝謝你取得了他的成果。

Hawking combined our understanding of gravity which is general relativity with our understanding of the very small, which is quantum mechanics, but he only did that in an approximate sense.

霍金將我們對廣義相對論的引力的理解與我們對極小物體的理解（即量子力學）相結合，但他只是在近似的意義上做到了這一點。

He assumed that the gravity was relatively weak at the event horizon.

他假設事件視界處的引力相對較弱。

That it didn't couple strongly to the quantum fields that were there.

它沒有與那裡的量子場發生強烈的耦合。

It could be that in a full theory of quantum gravity, something much more complex is happening at the event horizon.

可能在一個完整的量子引力理論中，在事件視界處發生了更復雜的事情。

Something we call a firewall Now, studio regulations prevented me from having an actual wall of fire to show you what would happen.

我們稱之為防火牆的東西 現在，工作室的規定使我無法有一個真正的火牆向你展示會發生什麼。

So instead I'm just gonna smash some eggs.

是以，我只是要砸碎一些雞蛋。

The key idea here is that in physics information is preserved and everything can be traced back to its roots.

這裡的關鍵想法是，在物理學中，資訊被保存下來，一切都可以追溯到它的根源。

If I smash this egg, all the information is preserved.

如果我打碎這個蛋，所有的資訊都會被保留下來。

If I wanted to I could retrace all the steps of all the molecules and reconstruct the egg?

如果我想，我可以追溯所有分子的所有步驟，並重建雞蛋？

It would be extraordinarily difficult, but it wouldn't be impossible.

這將是非常困難的，但也不是不可能。

So what happens in firewall theory is that if this egg were to hit the event horizon it would get obliterated and all its information would be spread across the event horizon and then that information would get tangled up with the Hawking radiation leaking out into space that way, when the black hole disappears, all the information is still there in the universe.

是以，在防火牆理論中發生的情況是，如果這個雞蛋撞上事件穹界，它將被湮沒，它的所有資訊將被傳播到事件穹界，然後這些資訊將與洩露到太空的霍金輻射糾纏在一起，這樣，當黑洞消失時，所有的資訊仍然存在於宇宙中。

And the paradox is resolved a little bit messily.

而這個悖論被解決得有點亂。

But but still resolved.

但但還是解決了。

You know, this is actually oddly satisfying anyway, we should move on.

你知道，無論如何，這其實是很奇怪的滿足，我們應該繼續前進。

Is there someone here to clean it up or it's me.

這裡有誰來清理，還是我。

It's me okay.

是我好了。

As intriguing as firewall theory is.

正如防火牆理論一樣耐人尋味。

It does have its shortcomings.

它確實有其不足之處。

Most importantly, we don't actually know how it works, how the information actually gets encoded on the event horizon and how it gets tangled up in the hawking radiation.

最重要的是，我們實際上不知道它是如何工作的，資訊實際上是如何被編碼在事件穹界上的，以及它是如何被糾纏在霍金輻射中的。

So it doesn't actually solve the paradox, it just moves it somewhere else.

所以它實際上並沒有解決這個悖論，只是把它移到了別的地方。

But in our studies of black holes we found something very intriguing and that has to do with holograms.

但在我們對黑洞的研究中，我們發現了一些非常耐人尋味的東西，這與全息圖有關係。

Yeah, yeah holograms but not the holograms.

是的，是全息圖，但不是全息圖。

You're thinking of holographic theory where multi dimensional information is stored on a lower dimensional of the substrate.

你想到的是全息理論，其中多元資訊被存儲在基體的低維上。

If you will, we found that when information flows into a black hole its surface area increases in proportion to the amount of information not its volume.

如果你願意，我們發現，當資訊流入黑洞時，其表面積的增加與信息量成正比，而不是其體積。

So this is telling us that somehow the information that goes into a black hole is getting stored or encoded on the surface area, not within the bulk of the black hole itself.

是以，這就告訴我們，進入黑洞的資訊以某種方式被儲存或編碼在表面區域，而不是在黑洞本身的內部。

What is this telling us?

這告訴我們什麼呢？

We're not exactly sure.

我們並不完全確定。

It could mean that a full theory of quantum gravity really only lives in two dimensions, not three or something else.

這可能意味著一個完整的量子引力理論真的只存在於兩個維度，而不是三個維度或其他。

I mean honestly, black holes are just plain confusing.

我的意思是，說實話，黑洞實在是太令人困惑了。