Can a black hole be destroyed? - Fabio Pacucci

翻译人员: Carol Wang 校对人员: Ziyao Wang

Black holes are among the most destructive objects in the universe.

黑洞是宇宙最具破坏性的物体之一，

Anything that gets too close to the central singularity of a black hole,

任何太靠近黑洞中心奇点的物体，

be it an asteroid, planet, or star,

无论是小行星，行星还是恒星，

risks being torn apart by its extreme gravitational field.

都有被其巨大引力场摧毁的危险。

And if the approaching object happens to cross the black hole’s event horizon,

如果接近黑洞的物体 恰好穿过黑洞的事件视界，

it’ll disappear and never re-emerge,

它将会消失，永不再出现，

adding to the black hole’s mass and expanding its radius in the process.

此过程中，黑洞质量增加， 而且黑洞半径扩大。

There is nothing we could throw at a black hole

没有任何扔向黑洞的东西

that would do the least bit of damage to it.

会对它造成一点损害

Even another black hole won’t destroy it–

即使另一个黑洞也无法摧毁它——

the two will simply merge into a larger black hole,

这两个黑洞只会合成一个更大的黑洞，

releasing a bit of energy as gravitational waves in the process.

此过程中释放出一点引力波能量。

By some accounts,

理论证明，

it’s possible that the universe may eventually consist entirely of black holes

在遥远的将来，

黑洞会组成整个宇宙。

in a very distant future.

And yet, there may be a way to destroy, or “evaporate,” these objects after all.

然而有一种方法 可能可以摧毁或“蒸发”这些黑洞。

If the theory is true,

如果那个理论可靠，

all we need to do is to wait.

我们只需要等待。

In 1974,

1974年，

Stephen Hawking theorized a process

斯蒂芬·霍金提出

that could lead a black hole to gradually lose mass.

一个可能导致黑洞 逐渐失去质量的过程：

Hawking radiation, as it came to be known,

霍金辐射学说。

is based on a well-established phenomenon called quantum fluctuations of the vacuum.

这个理论基于一种 真空量子波动的已知现象。

According to quantum mechanics,

根据量子力学，

a given point in spacetime fluctuates between multiple possible energy states.

时空中的一个点在多个 可能的能量状态之间波动。

These fluctuations are driven by the continuous creation and destruction

这些波动是由虚粒子对的

of virtual particle pairs,

不断产生和湮灭所造成的，

which consist of a particle and its oppositely charged antiparticle.

虚粒子对由粒子 和带相反电荷的反粒子组成。

Normally, the two collide and annihilate each other shortly after appearing,

通常两者出现后不久 就会相互碰撞和湮灭，

preserving the total energy.

总能量不变。

But what happens when they appear just at the edge of a black hole’s event horizon?

但它们出现在黑洞 事件视界时会发生什么呢？

If they’re positioned just right,

如果它们恰好位于视界边缘，

one of the particles could escape the black hole’s pull

一个粒子可能会逃脱黑洞引力，

while its counterpart falls in.

而另一个坠入黑洞。

It would then annihilate another oppositely charged particle

黑洞视界边缘内的粒子

会中和另一个带相反电荷的粒子，

within the event horizon of the black hole,

reducing the black hole’s mass.

从而减少黑洞的质量。

Meanwhile, to an outside observer,

对外部观察者来说，

it would look like the black hole had emitted the escaped particle.

就好像黑洞发射了逃逸粒子。

Thus, unless a black hole continues to absorb additional matter and energy,

因此，除非黑洞继续 吸收外部物质和能量，

it’ll evaporate particle by particle, at an excruciatingly slow rate.

它将以极其缓慢的速度蒸发粒子。

How slow?

有多慢呢？

A branch of physics, called black hole thermodynamics, gives us an answer.

黑洞热力学给出了答案。

When everyday objects or celestial bodies release energy to their environment,

日常物体或天体 向周围环境释放能量，

we perceive that as heat,

我们把其感受为热量，

and can use their energy emission to measure their temperature.

并且根据释放的能量 来测量它们的温度。

Black hole thermodynamics

黑洞热力学认为，

suggests that we can similarly define the “temperature” of a black hole.

我们也可以类似地 定义黑洞的“温度”。

It theorizes that the more massive the black hole,

该理论认为，黑洞质量越大，

the lower its temperature.

其温度越低。

The universe’s largest black holes

宇宙最大的黑洞，

would give off temperatures of the order of 10 to the -17th power Kelvin,

其温度为10的负17次方开尔文，

very close to absolute zero.

非常接近绝对零度。

Meanwhile, one with the mass of the asteroid Vesta

而一个与灶神星 同质量的黑洞的温度，

would have a temperature close to 200 degrees Celsius,

则接近200摄氏度，

thus releasing a lot of energy in the form of Hawking Radiation

它以霍金辐射的形式，

向寒冷的外部环境释放大量能量。

to the cold outside environment.

The smaller the black hole,

黑洞越小，

the hotter it seems to be burning–

其燃烧得更加炽热——

and the sooner it’ll burn out completely.

而且很快就会烧光。

Just how soon?

到底多快呢？

Well, don’t hold your breath.

好吧，别期望太高。

First of all, most black holes accrete, or absorb matter and energy,

首先，多数黑洞聚集 或吸收物质和能量的速度

more quickly than they emit Hawking radiation.

远远大于发出霍金辐射的速度，

But even if a black hole with the mass of our Sun stopped accreting,

即使一个与太阳质量 相同的黑洞停止了聚集物质能量，

it would take 10 to the 67th power years–

它也需要10的67次方年——

many many magnitudes longer than the current age of the Universe—

也就是比现在宇宙的年龄更长的时间——

to fully evaporate.

才能完全消失。

When a black hole reaches about 230 metric tons,

当黑洞达到230公吨左右时，

it’ll have only one more second to live.

它只会再生存一秒。

In that final second,

在最后一秒，

its event horizon becomes increasingly tiny,

它的事件视界变得越来越小，

until finally releasing all of its energy back into the universe.

直到最终将所有能量释放回宇宙。

And while Hawking radiation has never been directly observed,

虽然人们从未直接观察到霍金辐射，

some scientists believe that certain gamma ray flashes detected in the sky

但一些科学家认为，天空中 探测到的某些伽马射线闪光

are actually traces of the last moments

就是是远古时期形成的、

of small, primordial black holes formed at the dawn of time.

小的原始黑洞最后一刻的痕迹。

最终，在未知的遥远未来，

Eventually, in an almost inconceivably distant future,

the universe may be left as a cold and dark place.

宇宙会成为冰冷、黑暗之所。

But if Stephen Hawking was right,

但如果霍金辐射的理论是正确的，

before that happens,

在那发生之前，

the normally terrifying and otherwise impervious black holes

可怕而神秘莫测的黑洞，

will end their existence in a final blaze of glory.

将在最后的荣耀之火中湮灭。