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


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


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


  • 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.


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


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


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


  • But physicists are more concerned with quantum information.


  • 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.


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


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


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


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


  • 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.


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


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


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


  • 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.


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


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


  • 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.


  • 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.


  • Does that quantum information truly disappear?


  • If not, where does it go?


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


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


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


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


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


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


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


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


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


  • 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.


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


  • Ever wonder if a black hole could destroy us?


  • Or we could destroy a black hole?


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


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


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B2 中高級 中文 美國腔 TED-Ed 黑洞 悖論 量子 資訊 宇宙

【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)

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