黑洞只有兩個參數，形成機制卻仍是謎

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But if you ask somebody a bit more like me, who works on theory and is interested in the fundamental concepts, then a black hole is a very different beast. It's an object that curves spacetime to the extent that time stops at the event horizon.

但如果去問更接近我這種做理論、關心基本概念的人，那黑洞是個完全不同的東西——它是把時空彎曲到時間在事件視界處停止的物體。

Vitor Cardoso3:07

Any black hole in the universe. That means of all the trillions of black holes we think are out there, all of them are specified entirely by just two parameters.

宇宙中的任何黑洞——我們以為存在的數萬億個黑洞——全都只由兩個參數完全決定。

Vitor Cardoso10:47

If our planet, the Earth, would suddenly decide to collapse to a black hole and everything that composes the Earth would fall onto the black hole, it could not be a black hole because it's spinning too fast. And what the equations would tell us is there would be no horizon.

如果我們的星球地球突然決定坍縮成黑洞，地球的所有物質都掉進黑洞裡，那它也成不了黑洞，因為它自轉太快了。方程告訴我們的是：不會形成視界。

Vitor Cardoso19:34

We see black holes exist all the way up to 120 solar masses. We don't really know how they form.

我們看到黑洞一直存在到 120 倍太陽質量。我們並不真正知道它們是怎麼形成的。

Vitor Cardoso20:52

So if they were under the form of black holes, once in a while, micro black holes, one of these black holes would pass in front of a star, and it would lens the light from that star, so we would see the light from that star changing. And we haven't seen this.

所以如果暗物質以黑洞的形式存在，那麼偶爾，一個微型黑洞會從某顆恆星前經過，它會彎曲那顆恆星的光，我們會看到那顆恆星的光在變化。而我們從沒見過這種情況。

Vitor Cardoso28:59

they're reconstructed from, I would say, roughly 10%. So 90% of the image is reconstructed, and it's reconstructed based on thousands of simulations that we do of matter around black holes.

它們是在大約只有 10% 實測數據的基礎上重建出來的。所以圖像裡 90% 是重建的，而且重建依據是我們做的成千上萬次黑洞周圍物質模擬。

Vitor Cardoso37:15

Gravitational waves are not traveling at the speed of light. So I'm always expecting some news along that side of things. So I always get a bit not depressed, but okay, it's the speed of light with 15 decimal digits.

引力波不按光速傳播——所以我一直在期待這方面的新聞。所以我總有點，不是說抑鬱，而是：好吧，光速測到了 15 位小數。行吧。

Vitor Cardoso40:57

It's a fascinating thing to think that if dark matter would come under the form of axions, there might be systems there that look like atoms: a nucleus, which is a spinning black hole, surrounded by a cloud, like the hydrogen atom, a cloud of axions.

想想就著迷：如果暗物質以 axion 的形式存在，那麼可能有一套系統看起來像原子——原子核是一個旋轉黑洞，周圍環繞著一團雲，就像氫原子那樣，一團 axion 雲。

Vitor Cardoso1:00:37

數字與實體

術語

no-hair theorem無毛定理

真空中穩態黑洞僅由質量、自轉（及電荷）決定，沒有其它自由度。

Kerr metric克爾度規

描述旋轉黑洞外部時空的廣義相對論精確解。

light ring光環

光子能繞黑洞做圓周運動的最內層軌道，決定陰影形狀。

cosmic censorship宇宙監督假設

猜測物理奇點總被事件視界遮擋，裸奇點不會在自然界出現。

matched filtering匹配濾波

用理論波形模板與探測器輸出比對，從噪聲中提取引力波信號。

last parsec problem最後一秒差距問題

兩個超大質量黑洞靠近到約 1 秒差距後缺乏機制繼續合併，與觀測矛盾。

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