黑洞只有两个参数，形成机制却仍是谜

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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.

但如果去问更接近我这种做理论、关心基本概念的人，那黑洞是个完全不同的东西——它是把时空弯曲到时间在事件视界处停止的物体。

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——我们以为存在的数万亿个黑洞——全都只由两个参数完全决定。

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.

如果我们的星球地球突然决定坍缩成黑洞，地球的所有物质都掉进黑洞里，那它也成不了黑洞，因为它自转太快了。方程告诉我们的是：不会形成视界。

Vitor Cardoso19:34

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

我们看到黑洞一直存在到 120 倍太阳质量。我们并不真正知道它们是怎么形成的。

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.

所以如果暗物质以黑洞的形式存在，那么偶尔，一个微型黑洞会从某颗恒星前经过，它会弯曲那颗恒星的光，我们会看到那颗恒星的光在变化。而我们从没见过这种情况。

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.

它们是在大约只有 10% 实测数据的基础上重建出来的。所以图像里 90% 是重建的，而且重建依据是我们做的成千上万次黑洞周围物质模拟。

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.

引力波不按光速传播——所以我一直在期待这方面的新闻。所以我总有点，不是说抑郁，而是：好吧，光速测到了 15 位小数。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.

想想就着迷：如果暗物质以 axion 的形式存在，那么可能有一套系统看起来像原子——原子核是一个旋转黑洞，周围环绕着一团云，就像氢原子那样，一团 axion 云。

Vitor Cardoso1:00:37

数字与实体

术语

no-hair theorem无毛定理

真空中稳态黑洞仅由质量、自转（及电荷）决定，没有其它自由度。

Kerr metric克尔度规

描述旋转黑洞外部时空的广义相对论精确解。

light ring光环

光子能绕黑洞做圆周运动的最内层轨道，决定阴影形状。

cosmic censorship宇宙监督假设

猜测物理奇点总被事件视界遮挡，裸奇点不会在自然界出现。

matched filtering匹配滤波

用理论波形模板与探测器输出比对，从噪声中提取引力波信号。

last parsec problem最后一秒差距问题

两个超大质量黑洞靠近到约 1 秒差距后缺乏机制继续合并，与观测矛盾。

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