Name: 【TED-Ed】近代最偉大的物理學家：霍金之黑洞悖論解析 (Hawking's black hole paradox explained - Fabio Pacucci)
Uploaded: 2020-02-14T21:01:10.000Z
Duration: 5 min 38 s

關係子句

Scientists work on the boundaries of the unknown, where every new piece of knowledge forms a path into a void of uncertainty.

科學家致力於探索未知的邊界，每一次新知的發現都開啓一條通往未知可能性的路。

And nothing is more uncertain, or potentially enlightening, than a paradox.

沒有什麼比悖論更不確定的了—或，更有啟發的潛力。

Throughout history, paradoxes have threatened to undermine everything we know, and just as often, they've reshaped our understanding of the world.

縱觀歷史，悖論一直挑戰著我們所知的一切，但它們同樣經常重新建構我們對世界的了解。

Today, one of the biggest paradoxes in the universe threatens to unravel the fields of general relativity and quantum mechanics: the black hole information paradox.

現今，宇宙中最大的悖論之一威脅著「廣義相對論」與「量子力學」領域：「黑洞資訊悖論」。

To understand this paradox, we first need to define what we mean by "information."

要了解這個悖論，我們先要定義這裡所謂的「資訊」是什麼。

Typically, the information we talk about is visible to the naked eye.

通常，我們所說的資訊是用肉眼可以看見的。

For example, this kind of information tells us that an apple is red, round, and shiny.

比如，這種資訊告訴我們蘋果是紅色的、圓形的、有光澤。

But physicists are more concerned with quantum information.

但物理學家更在乎的是量子資訊。

This refers to the quantum properties of all the particles that make up that apple, such as their position, velocity, and spin.

也就是：構成這顆蘋果的 所有粒子有什麼量子特性，比如它們的位置、速度、自旋。

Every object in the Universe is composed of particles with unique quantum properties.

宇宙中的所有物質都由具有獨特量子特性的粒子所構成。

This idea is evoked most significantly in a vital law of physics: "the total amount of quantum information in the Universe must be conserved".

一個重要的物理定律體現了這個想法：「宇宙中所有量子資訊的總量必須守恆」。

Even if you destroy an object beyond recognition, its quantum information is never permanently deleted.

即使我們把物體摧毀到無法辨識，它的量子資訊也永遠不會消失。

And theoretically, knowledge of that information would allow us to recreate the object from its particle components.

理論上，一旦知道那些資訊，我們就可以用該物體的粒子元件將該物體重建出來。

Conservation of information isn't just an arbitrary rule, but a mathematical necessity, upon which  much of modern science is built.

資訊守恆並不只是任意的一條法則，它在數學上有其必要性，且是大部分現代科學的建構基礎。

But around black holes, those foundations get shaken.

但在黑洞附近， 那些根基受到動搖。

When an apple enters a black hole, it seems as though it leaves the Universe, and all its quantum information becomes irretrievably lost.

當一顆蘋果進入黑洞，它就好像離開了這個宇宙，它會失去它所有的量子資訊，且無法挽回。

However, this doesn't immediately break the laws of physics.

然而，這不會馬上破壞物理的法則。

The information is out of sight, but it might still exist within the black hole's mysterious void.

資訊雖然看不見，但它可能仍然存在於黑洞的神秘空洞當中。

Alternatively, some theories suggest that information doesn't even make it inside the black hole at all.

另一種說法是，那些資訊甚至根本沒有進入到黑洞中。

Seen from outside, it's as if the apple's quantum information is encoded on the surface layer of the black hole, called the event horizon.

從外面看，似乎蘋果的量子資訊被編碼在黑洞的表層上，也就是「事相面 (事件視界)」。

As the black hole's mass increases, the surface of the event horizon increases as well.

當黑洞的質量增加，事相面的表面也會增加。

So it's possible that as a black hole swallows an object, it also grows large enough to conserve the object's quantum information.

所以，的確有可能，當黑洞吞噬物體時，它也會長大到一個程度，讓該物體的量子資訊可以守恆。

But whether information is conserved inside the black hole or on its surface, the laws of physics remain intact—until you account for Hawking radiation.

但，不論資訊守恆是發生在黑洞內或黑洞表面，物理的定律仍然不受影響—除非你要去說明「霍金輻射」。

Discovered by Stephen Hawking in 1974, this phenomenon shows that black holes are gradually evaporating.

1974 年史帝芬霍金發現了這種現象，它顯示黑洞會漸漸蒸發。

Over incredibly long periods of time black holes lose mass as they shed particles away from their event horizons.

經過非常長的時間之後，黑洞的事相面會散失粒子，因而失去一些質量。

Critically, it seems as though the evaporating particles are unrelated to the information the black hole encodes, suggesting that a black hole and all the quantum information it contains could be completely erased.

重要的是，蒸發的粒子看起來似乎和黑洞編碼的資訊沒有關聯—這就意味著，黑洞和它含有的所有量子資訊能被完全抹除。

Does that quantum information truly disappear?

While the evaporation process would take an incredibly long time, the questions it raises for physics are far more urgent.

雖然蒸發過程會花非常長的時間，它帶給物理的問題更急迫。

The destruction of information would force us to rewrite some of our most fundamental scientific paradigms.

資訊的毀滅會迫使我們重寫我們最基礎的科學範式。

But fortunately, in science, every paradox is an opportunity for new discoveries.

但，幸運的是，在科學上，每一個範式都是新發現的機會。

Researchers are investigating a broad range of possible solutions to the information paradox.

針對「資訊悖論」，研究者在探究各種可能的解決方案。

Some have theorized that information actually is encoded in the escaping radiation, in some way we can't yet understand.

有些研究者推理說資訊其實是被編碼在逃逸輻射上，用的是我們尚無法理解的編碼方式。

Others have suggested the paradox is just a misunderstanding of how general relativity and quantum field theory interact.

其他研究者則認為悖論只是誤解，誤會了「廣義相對論」和「量子場論」如何產生交互作用。

Respectively, these two theories describe the largest and smallest physical phenomena, and they're notoriously difficult to combine.

這兩種理論分別描述了最大和最小的物理現象，這兩者本來就是出了名的難結合。

Some researchers argue that a solution to this and many other paradoxes will come naturally with a "unified theory of everything."

有些研究者主張，對這個悖論及許多其他悖論而言，解決方案自然會隨著「統一的萬物論」出現。

But perhaps the most mind-bending  theory to come from exploring this paradox is the holographic principle".

但，也許在探究這個悖論時，最難以理解的理論是「全像原理」。

Expanding on the idea that the 2D surface of an event horizon can store quantum information, this principle suggests that the very boundary of the observable universe is also a 2D surface encoded with information about real, 3D objects.

事相面的 2D 表面能夠儲存量子資訊，這個想法延伸出了全像原理，該原理指出，可觀測宇宙的每一條邊界也都是 2D 表面，且有關於真實 3D 物體的資訊被編碼在這表面上。

If this is true, it's possible that reality as we know it is just a holographic projection of that information.

如果這是真的， 有可能我們所知道的真實只是那些資訊的全像投影。

If proven, any of these theories would open up new questions to explore, while still preserving our current models of the universe.

如果得到證明，上述任一個理論都能夠開啟探索的新方向，同時還能沿用我們目前的宇宙模型。

But it's also possible that those models are wrong! Either way, this paradox has already helped us take another step into the unknown.

但，也有可能那些模型是錯的！不管怎樣，這個悖論已經讓我們向未知更進一步了。

Ever wonder if a black hole could destroy us?

有沒有想過黑洞是否可以消滅我們？

Cast your lot for or against humanity by watching one of these videos next.

想得知人類是否能與黑洞共存，就繼續看接下來的影片吧！