Name: 【TED-Ed】地球可能被黑洞吸掉嗎？ (Could the Earth be swallowed by a black hole? - Fabio Pacucci)
Uploaded: 2018-09-25T02:32:25.000Z
Duration: 5 min 11 s

From asteroids capable  of destroying entire species,

從可以摧毀整個物種的小行星，

to gamma-ray bursts and supernovae  that could exterminate life on Earth,

到可以讓地球上所有生命滅絕的

關係子句

outer space has no shortage of forces that could wreak havoc on our tiny planet.

that seems more terrifying  than any of these –

可以在我們的小小星球上 造成大浩劫的力量。

something that wipes out  everything it comes near.

Could the Earth  be swallowed by a black hole?

任何東西只要靠近它 就會被徹底消滅。

that space and time around it  are inescapably modified,

地球有沒有可能會被黑洞給吞噬？

Nothing, not even light, can move fast enough

高到它周圍的空間和時間 都無法避免地被改變，

to escape a black hole's  gravitational pull

Thus, a black hole is like a cosmic vacuum cleaner with infinite capacity,

gobbling up everything in its path,  and letting nothing out.

也就是所謂的事件視界， 就無法脫離了。

To determine whether a black hole  could swallow the Earth,

因此，黑洞是個容量 無限大的宇宙吸塵器，

we first have to figure out  where they are.

狼吞虎咽它經過的一切， 什麼都不放過。

But since they don't emit light,  how's that possible?

若要判斷一個黑洞 是否會把地球吞噬，

Fortunately, we're able to observe  their effect on the space around them.

但它們不會散發光線， 怎麼可能找到它們？

the immense gravitational field accelerates it to high speed.

幸運的是，我們可以觀察 它們對於周圍空間的影響。

And for objects too far away  to be sucked in,

非常大的重力場會讓它加速 到極高的速度。

the massive gravitational force  still affects their orbits.

If we observe several stars orbiting around an apparently empty point,

至於太遠而不會被吸進去的物體，

極大的引力仍然會影響它們的軌道。

Similarly, light that passes close enough to an event horizon

如果我們觀察到有許多星星明顯 在一個空的點周圍繞軌運行時，

will be deflected in a phenomenon  known as gravitational lensing.

很可能就是黑洞在帶領它們跳舞。

Most of the black holes that we've found  can be thought of as two main types.

同樣的，路過的光 如果太靠近事件視界，

The smaller ones,  called stellar mass black holes,

會因為所謂的重力透鏡效應而轉向。

have a mass up to 100 times larger  than that of our sun.

我們所發現的黑洞 大部分可分為兩種主要類型。

They're formed when a massive star  consumes all its nuclear fuel

質量比我們的太陽還要大一百倍。

We've observed several of these objects as close as 3000 light-years away,

當一個大質量的星星 消耗光了它所有的核燃料，

and there could be up to 100 million  small black holes

我們觀察到這些物體中 有幾個距離我們近三千光年，

我們應該要擔心嗎？可能不用。

stellar black holes only have a radius  of around 300 kilometers or less,

儘管恆星質量黑洞的質量很大，

making the chances  of a direct hit with us miniscule.

它們的半徑只有 約三百公里，甚至更小，

Although because  their gravitational fields

因此，直接衝向我們的機會非常小。

can affect a planet from a large distance,

they could be dangerous  even without a direct collision.

可以在很遠的距離就影響到星球，

If a typical stellar-mass black hole  were to pass in the region of Neptune,

即使沒有直接衝撞， 它們也具有危險性。

the orbit of the Earth  would be considerably modified,

如果一個典型的恆星質量黑洞 通過海王星一帶，

地球的軌道可能會被大大地改變，

Still, the combination of how small  they are and how vast the galaxy is

means that stellar black holes don't give us much to worry about.

不過，黑洞非常小， 再加上銀河非常大，

But we still have to meet the second type:

也就是說，我們不需要 太擔心恆星質量黑洞。

但我們仍然得要談談 第二種黑洞：超大質量黑洞。

These have masses millions or billions times greater than that of our sun

它們的質量比我們的太陽 大數百萬或數十億倍，

and have event horizons that could span billions of kilometers.

These giants have grown  to immense proportions

by swallowing matter  and merging with other black holes.

以及跟其他黑洞合併 而變得如此巨大。

supermassive black holes aren't wandering through space.

超大質量黑洞不會在宇宙中閒逛。

Instead, they lie at the center  of galaxies, including our own.

反之，它們會停留在銀河的中心， 包括我們的銀河。

Our solar system is in a stable orbit  around a supermassive black hole

我們的太陽系的運行軌道是繞著 超大質量黑洞的穩定軌道，

that resides  at the center of the Milky Way,

at a safe distance of 25,000 light-years.

保持兩萬五千光年的安全距離。

若我們的銀河系 和另一個銀河系相撞，

the Earth could be thrown towards  the galactic center,

close enough  to the supermassive black hole

In fact, a collision  with the Andromeda Galaxy

is predicted to happen  4 billion years from now,

which may not be great news for our home planet.

對於我們的家鄉地球來說， 這並不是好消息。

但在我們也不要 太嚴厲地評斷黑洞，

black holes aren't simply agents  of destruction.

They played a crucial role  in the formation of galaxies,

對於銀河系的形成， 它們也扮演了重要的角色，

Far from being shadowy characters  in the cosmic play,

在這齣宇宙劇中， 黑洞演的並不是帶來陰影的角色，

black holes have fundamentally contributed

基本上，它們做出了很多貢獻，

in making the universe  a bright and astonishing place.

讓宇宙成為一個明亮、 令人驚奇的地方。