the very simple fact

請各位思考一下

that, by far,

一個非常簡單的事實

most of what we know about the universe

目前為止

comes to us from light.

我們所知的宇宙

We can stand on the Earth and look up at the night sky

都透過「光」而來

and see stars with our bare eyes.

站在地球上仰望夜空

The Sun burns our peripheral vision.

我們憑肉眼就能看得見星星

We see light reflected off the Moon.

太陽照亮我們的視野邊界

And in the time since Galileo pointed that rudimentary telescope

因為光的反射而看見月亮

at the celestial bodies,

自從伽利略以最原始的望遠鏡

the known universe has come to us through light,

舉目望天開始了觀測

across vast eras in cosmic history.

一向以來，已知宇宙都是透過光來向我們傳達訊息

And with all of our modern telescopes,

即便穿越了宇宙浩瀚的歷史

we've been able to collect

以現代的望遠鏡

this stunning silent movie of the universe --

我們能接收

these series of snapshots

這齣令人驚異、讚歎的宇宙無聲電影

that go all the way back to the Big Bang.

用許多連續圖形

And yet, the universe is not a silent movie

一路回溯至大霹靂時期

because the universe isn't silent.

但是，宇宙上演的並不是一齣默劇

I'd like to convince you

因為宇宙其實並非一片死寂

that the universe has a soundtrack

我想說服你們的就是這件事

and that soundtrack is played on space itself,

宇宙是個有聲電影

because space can wobble like a drum.

宇宙自己發出聲音成為它的聲部

It can ring out a kind of recording

這是因為太空像鼓一樣會震動

throughout the universe

它像唱片一樣可以發出聲音

of some of the most dramatic events as they unfold.

傳遍整個宇宙

Now we'd like to be able to add

尤其當某些極富戲劇效果的事件展開的時候

to a kind of glorious visual composition

現在我們想嘗試

that we have of the universe --

在炫麗奪目的視覺效果以外

a sonic composition.

為我們的宇宙再加上

And while we've never heard the sounds from space,

它聲音的部份

we really should, in the next few years,

雖然我們從沒聽過來自太空的聲音

start to turn up the volume on what's going on out there.

幾年之內，我們應該可以開始

So in this ambition

把外面世界發出的聲音音量再調更大

to capture songs from the universe,

在這雄心壯志

we turn our focus

企圖接收宇宙譜出的歌曲驅動下

to black holes and the promise they have,

帶領我們將目光轉向

because black holes can bang on space-time

黑洞和它們的能量特性

like mallets on a drum

因為黑洞能在空-時中發出聲響

and have a very characteristic song,

像一根鼓棒一樣

which I'd like to play for you -- some of our predictions

它的歌曲則極富特色

for what that song will be like.

在此根據我們的假設

Now black holes are dark against a dark sky.

將要播放一段黑洞可能會發出的聲音

We can't see them directly.

黑洞是襯在黑底之上

They're not brought to us with light, at least not directly.

不可能直接看得見

We can see them indirectly,

它們不是直接以光的形式向我們呈現,至少沒有以直接的方式

because black holes wreak havoc on their environment.

我們能以間接的方式看見它們

They destroy stars around them.

也就是黑洞對它週遭環境施加的破壞

They churn up debris in their surroundings.

諸如毀滅周圍恆星

But they won't come to us directly through light.

將方圓以內碎片劇烈攪拌...等

We might one day see a shadow

總之它們不會以可見光讓我們看見

a black hole can cast on a very bright background,

有一天我們或許看得見它的影子

but we haven't yet.

當黑洞遇上一個非常明亮的背景時這就有可能

And yet black holes may be heard

但現在還在努力中

even if they're not seen,

但黑洞是可以聽得見的

and that's because they bang on space-time like a drum.

就算它們真的是我們所不能看見的

Now we owe the idea that space can ring like a drum

能聽見黑洞是因它像鼓一樣,敲槌著空時

to Albert Einstein -- to whom we owe so much.

我們會有這麼一個太空中響著鼓聲的念頭

Einstein realized that if space were empty,

最該感謝的人是愛因斯坦，非常感謝

if the universe were empty,

愛因斯坦明瞭如果太空是空的

it would be like this picture,

宇宙是空的

except for maybe without the helpful grid drawn on it.

就像這張照片

But if we were freely falling through the space,

或者說實際上應沒有這些輔助線會像得更徹底些

even without this helpful grid,

不過如果我們自由的墜入太空中

we might be able to paint it ourselves,

就算沒有這些輔助線

because we would notice that we traveled along straight lines,

我們自己也能畫的出這幅圖

undeflected straight paths

因為我們會注意到自己是以直線運動前進

through the universe.

以直線不偏轉的路徑

Einstein also realized --

通過宇宙

and this is the real meat of the matter --

愛因斯坦還想到另一件事

that if you put energy or mass in the universe,

而那個部份才是更加精采

it would curve space,

也就是，若將能量或質量放在宇宙中

and a freely falling object

它會彎曲空間

would pass by, let's say, the Sun

而自由落下的物體

and it would be deflected

有可能會經過，譬如說，太陽

along the natural curves in the space.

於是它的路徑會受偏轉

It was Einstein's great general theory of relativity.

沿著空間自然曲線偏轉

Now even light will be bent by those paths.

這是愛因斯坦的普通相對論

And you can be bent so much

因為連光都會受這些路徑影響而彎曲

that you're caught in orbit around the Sun,

彎曲到一個程度

as the Earth is, or the Moon around the Earth.

你會被太陽抓住而繞著它依軌道運轉

These are the natural curves in space.

就像地球繞太陽轉，月亮繞地球轉

What Einstein did not realize

這就是空間的自然曲線

was that, if you took our Sun

愛因斯坦沒想通的事情是

and you crushed it down to six kilometers --

如果你拿著太陽

so you took a million times the mass of the Earth

把它擠壓直到只剩6公里直徑大小

and you crushed it to six kilometers across,

這是一團質量是地球100萬倍的東西

you would make a black hole,

然後把它的體積壓縮到6公里寬

an object so dense

這樣就是個黑洞

that if light veered too close, it would never escape --

一個非常嚴密的物質

a dark shadow against the universe.

如果靠得太近，連光不可能逃走

It wasn't Einstein who realized this,

成為一個相對於宇宙的黑色陰影

it was Karl Schwarzschild

愛因斯坦沒領悟到這件事情

who was a German Jew in World War I --

這是卡爾史瓦西解出來的

joined the German army already an accomplished scientist,

他是德國猶太人，在第一次世界大戰時

working on the Russian front.

在入伍時已是一位傑出科學家

I like to imagine Schwarzschild in the war in the trenches

在德俄邊境前線工作

calculating ballistic trajectories for cannon fire,

我總愛想像史瓦西是躲在戰爭時期的壕溝裡頭

and then, in between,

邊計算高射炮的發射彈道

calculating Einstein's equations --

邊偶爾計算一下

as you do in the trenches.

愛因斯坦的公式

And he was reading Einstein's recently published

壕溝裡能做的事情不多

general theory of relativity,

他正拜讀愛因斯坦最新的

and he was thrilled by this theory.

普通相對論

And he quickly surmised

令他大感驚訝的理論

an exact mathematical solution

他很快推算出

that described something very extraordinary:

一道精確的數學解答

curves so strong

極不尋常的描述了一個現象

that space would rain down into them,

一道強大的曲線

space itself would curve like a waterfall

空間會順勢下流

flowing down the throat of a hole.

空間本身會像瀑布一般的彎曲

And even light could not escape this current.

向下流入一個喉嚨敞開的洞

Light would be dragged down the hole

即便是光也無法逃離這股流勢

as everything else would be,

光會被拉入這個洞中

and all that would be left would be a shadow.

和其他任何東西一樣

Now he wrote to Einstein,

所有東西最後都會只剩下一個影子

and he said, "As you will see,

史瓦西寫信告訴愛因斯坦

the war has been kind to me enough.

他說,「且看,

Despite the heavy gunfire,

戰爭對我是多麼慷慨有餘啊,

I've been able to get away from it all

即便在戰火交織下

and walk through the land of your ideas."

我也能有遠離這一切的一個某處可去

And Einstein was very impressed with his exact solution,

一步步前進在由你的理論所佔領的土地上。」

and I should hope also the dedication of the scientist.

愛因斯坦對史瓦西精確的解答實在印象深刻

This is the hardworking scientist under harsh conditions.

我應該期望自己有科學家這樣全心全力

And he took Schwarzschild's idea

在這樣艱困的處境下仍辛勤工作

to the Prussian Academy of Sciences the next week.

帶著著史瓦西的理論想法

But Einstein always thought black holes were a mathematical oddity.

一週後，愛因斯坦前往波斯科學院

He did not believe they existed in nature.

愛因斯坦一向以為黑洞只不過是個純數學的怪物

He thought nature would protect us from their formation.

他並不相信自然界真有這個東西存在

It was decades

他認為自然界應該會在創生的過程中保護我們

before the term "black hole" was coined

幾十年過去

and people realized

黑洞一詞被憑空創造問世

that black holes are real astrophysical objects --

人們理解到

in fact they're the death state

黑洞是天文物理中真實的天體

of very massive stars

事實上它們是一種最終的境界

that collapse catastrophically

大質量恆星們的最終結局

at the end of their lifetime.

災難性的崩塌瓦解

Now our Sun will not collapse to a black hole.

當它的生命走到盡頭時

It's actually not massive enough.

我們的太陽不會塌縮成黑洞

But if we did a little thought experiment --

事實上它的質量還不夠形成為黑洞

as Einstein was very fond of doing --

但如果我們運用思考來做個實驗

we could imagine

就像愛因斯坦很喜歡做的事情一樣

putting the Sun crushed down to six kilometers,

我們不妨想像

and putting a tiny little Earth around it in orbit,

把太陽壓縮成６公里大小

maybe 30 kilometers

把一個超微小地球放在它旁邊依軌道運行

outside of the black-hole sun.

距離約30公里

And it would be self-illuminated,

在這顆太陽黑洞外面30公里處

because now the Sun's gone, we have no other source of light --

然後地球自己會發光

so let's make our little Earth self-illuminated.

因為沒有太陽了,我們也將失去光源--

And you would realize you could put the Earth in a happy orbit

只好先假設地球變成是發光體的情形

even 30 km

你會發現這個距離之下地球軌道

outside of this crushed black hole.

在距離黑洞

This crushed black hole

30公里以外

actually would fit inside Manhattan, more or less.

一個被壓縮的黑洞

It might spill off into the Hudson a little bit

事實上就和紐約市中心的曼哈頓區差不多大而已

before it destroyed the Earth.

有時它或許會碰到一點哈得遜區

But basically that's what we're talking about.

在它快要吞滅地球之前

We're talking about an object that you could crush down

基本上我們說的就是體積這麼小的一個東西

to half the square area of Manhattan.

我們說的這個東西是你可以把它壓縮到

So we move this Earth very close --

只有曼哈頓方圓一半大的區域

30 kilometers outside --

我們把這個地球移動到非常靠近 --

and we notice it's perfectly fine orbiting around the black hole.

30公里外的這個距離

There's a sort of myth

這是繞行這顆黑洞完美的軌道

that black holes devour everything in the universe,

這有點神秘

but you actually have to get very close to fall in.

黑洞無一例外的吞滅宇宙裡的一切物體

But what's very impressive is that, from our vantage point,

但事實上你必須非常靠近它才能掉的下去

we can always see the Earth.

但令人驚訝的是,從我們的觀望點

It cannot hide behind the black hole.

我們總是看得到地球

The light from the Earth, some of it falls in,

它沒辦法躲藏在黑洞的後方

but some of it gets lensed around and brought back to us.

這時有些從地球發出的光會掉入黑洞中

So you can't hide anything behind a black hole.

有些會因受到透鏡得作用,傳回來讓我們看見

If this were Battlestar Galactica

你沒辦法把一樣東西藏在黑洞後面

and you're fighting the Cylons,

如果是在科幻影集「太空堡壘」中

don't hide behind the black hole.

你和塞隆人正在作戰

They can see you.

千萬別選在一個黑洞的後面跟他玩躲迷藏

Now, our Sun will not collapse to a black hole --

敵人一定會看見你

it's not massive enough --

太陽不會塌縮成黑洞

but there are tens of thousands of black holes in our galaxy.

它質量不夠

And if one were to eclipse the Milky Way,

我們的銀河系裡有上萬顆黑洞

this is what it would look like.

如果銀河系裡發生了「食」的現象

We would see a shadow of that black hole

看起來會像這樣

against the hundred billion stars

我們會看到一個黑洞的影子

in the Milky Way Galaxy and its luminous dust lanes.

在數千億顆明亮恆星的映襯之下

And if we were to fall towards this black hole,

在銀河系還有許多明亮的塵埃帶中

we would see all of that light lensed around it,

若我們朝黑洞裡頭掉進去

and we could even start to cross into that shadow

我們會看見受到透鏡作用的光環繞在外層

and really not notice that anything dramatic had happened.

我們甚至開始穿透那個陰影

It would be bad if we tried to fire our rockets and get out of there

卻並不會真的發現什麼太有戲劇效果的事情

because we couldn't,

試圖從黑洞裡發射一顆火箭逃出來並不是個太好的主意

anymore than light can escape.

因為根本不可行

But even though the black hole is dark from the outside,

連光都逃不掉

it's not dark on the inside,

不過雖然黑洞從外面看是漆黑一片

because all of the light from the galaxy can fall in behind us.

內層卻不是黑的

And even though, due to a relativistic effect known as time dilation,

因為所有銀河系而來的光都在我們身後掉進來

our clocks would seem to slow down

儘管如此,由於時間膨脹的相對關係

relative to galactic time,

我們的時鐘會慢下來

it would look as though the evolution of the galaxy

相對於星系時間

had been sped up and shot at us,

看起來會好像是銀河系的演化

right before we were crushed to death by the black hole.

加速度進行並且正對著我們而來

It would be like a near-death experience

然後我們將被黑洞壓碎而死掉

where you see the light at the end of the tunnel,

很像是個瀕死經驗

but it's a total death experience.

看得見光在隧道末端...

(Laughter)

但這經驗其實會讓你非死不可

And there's no way of telling anybody

(笑聲)

about the light at the end of the tunnel.

你也沒辦法跟任何人說這個經歷

Now we've never seen a shadow like this of a black hole,

說你看得見光在隧道末端...

but black holes can be heard,

我們從來沒看見過像這樣的一個黑洞的影子

even if they're not seen.

但是我們聽得見黑洞

Imagine now taking an astrophysically realistic situation --

雖然就算看不到

imagine two black holes that have lived a long life together.

想像現在天文物理中有這樣一個現實情境

Maybe they started as stars

有兩個黑洞在一起,已經過了很久的時間

and collapsed to two black holes --

也許從它們是恆星的身分開始

each one 10 times the mass of the Sun.

然後崩塌為兩個黑洞

So now we're going to crush them down to 60 kilometers across.

每一個都有太陽質量的十倍大

They can be spinning

所以現在我們把它們壓縮為60公里大小

hundreds of times a second.

它們可能在自轉

At the end of their lives,

以每秒數百次的速度自轉

they're going around each other very near the speed of light.

當它們的恆星生命走到盡頭時

So they're crossing thousands of kilometers

它們以幾乎是光速互繞對方轉

in a fraction of a second,

以每秒數千里的速度

and as they do so, they not only curve space,

快速移動

but they leave behind in their wake

如此,不只扭曲了空間

a ringing of space,

它們也在所經之處的後方

an actual wave on space-time.

留下一個發出響聲的空間

Space squeezes and stretches

在空時中有一道實際的波

as it emanates out from these black holes

太空壓縮也延伸

banging on the universe.

這些自黑洞中發出來的波

And they travel out into the cosmos

敲擊著宇宙

at the speed of light.

它們朝向宇宙

This computer simulation

以光速奔去

is due to a relativity group at NASA Goddard.

這個電腦模擬結果

It took almost 30 years for anyone in the world to crack this problem.

是由美國航太總署戈達德太空中心的相對論組製作

This was one of the groups.

地球上很多人近30年時間都用來解答出這一道題目

It shows two black holes in orbit around each other,

戈達德小組是其中之一

again, with these helpfully painted curves.

它顯示的情況是兩個黑洞彼此互繞

And if you can see -- it's kind of faint --

如前述,藉由自然界事先就畫好的曲線

but if you can see the red waves emanating out,

它們看起來有點暗淡

those are the gravitational waves.

但你看得見紅色的波向外散射

They're literally the sounds of space ringing,

這就是重力波

and they will travel out from these black holes at the speed of light

使太空發出聲響

as they ring down and coalesce

它們從黑洞裡以光速跑出來