中子星——除了黑洞以外最極端的存在：英語精讀講義

Neutron stars are one of the most extreme and violent things in the universe. 文法

中子星是宇宙中最極端、最狂暴的事物之一。

Giant atomic nuclei only a few kilometers in diameter,

直徑只有幾公里的巨大原子核，

but as massive as stars.

但質量卻和恆星相當。

And they owe their existence to the death of something majestic. 片語搭配

它們的存在歸功於某種宏偉事物的死亡。

Stars exist because of a fragile balance.

恆星之所以存在，是因為一種脆弱的平衡。

The mass of millions of billions of trillions of tons of hot plasma

成千上萬億兆噸的高溫電漿

are being pulled inwards by gravity and squeeze material together with so much force that nuclei fuse. 文法

被重力向內拉扯，並以極大的力量將物質擠壓在一起，導致原子核發生核融合。

Hydrogen fuses into helium.

氫融合合成氦。

This releases energy,

這釋放出能量，

which pushes against gravity and tries to escape.

對抗重力並試圖向外逃逸。

As long as this balance exists, 文法

只要這種平衡存在，

stars are pretty stable.

恆星就非常穩定。

Eventually, the hydrogen will be exhausted.

最終，氫會被耗盡。

Medium stars like our sun go through a giant phase 片語動詞

像我們太陽這樣的中等恆星會經歷一個巨大的階段，

where they burn helium into carbon and oxygen

在這個階段，它們將氦燃燒成碳和氧，

before they eventually turn into white dwarfs.

然後最終變成白矮星。

But in stars many times the mass of our sun,

但在質量是我們太陽許多倍的恆星中，

things get interesting when the helium is exhausted.

當氦耗盡時，事情就變得有趣了。

For a moment,

有那麼一瞬間，

the balance of pressure and radiation tips 慣用語

壓力和輻射的平衡被打破，

and gravity wins,

重力佔據上風，

squeezing the star tighter than before.

以前所未有的力度擠壓恆星。

The core burns hotter and faster

核心燃燒得更熱、更快，

while the outer layers of the star swell by hundreds of times,

而恆星的外層則膨脹數百倍，

fusing heavier and heavier elements. 文法

融合出越來越重的元素。

Carbon burns to neon in centuries,

碳在幾個世紀內燃燒成氖，

neon to oxygen in a year,

氖在一年內變成氧，

oxygen to silicon in months,

氧在幾個月內變成矽，

and silicon to iron in a day.

而矽在一天內變成鐵。

And then, death.

然後，死亡。

Iron is nuclear ash.

鐵是核灰燼。

It has no energy to give and cannot be fused.

它沒有能量可釋放，也不能發生核融合。

The fusion suddenly stops and the balance ends.

核融合突然停止，平衡就此終結。

Without the outward pressure from fusion, 文法

沒有了核融合向外施加的壓力，

the core is crushed by the enormous weight of the star above it.

核心被上方恆星的巨大重量壓碎。

What happens now is awesome and scary.

接下來發生的事情既令人敬畏又令人恐懼。

Particles like electrons and protons really don't want to be near each other. 慣用語

像電子和質子這樣的粒子真的不想彼此靠近。

But the pressure of the collapsing star is so great

但是坍縮恆星的壓力是如此之大，

that electrons and protons fuse into neutrons,

以至於電子和質子融合成中子，

which then get squeezed together as tightly as in atomic nuclei.

然後它們被擠壓得像原子核中一樣緊密。

An iron ball the size of the Earth 表達脈絡

一個地球大小的鐵球

is squeezed into a ball of pure nuclear matter the size of a city.

被擠壓成一個城市大小、純粹由核物質組成的球體。

But not just the core, the whole star implodes,

但不僅僅是核心，整顆恆星都會向內發生內爆，

gravity pulling the outer layers in at 25% the speed of light.

重力以光速的25%將外層向內拉扯。

This implosion bounces off the iron core,

這種內爆在鐵芯上反彈，

producing a shock wave that explodes outwards

產生向外爆炸的衝擊波，

and catapults the rest of the star into space. 用詞

並將恆星的其餘部分彈射到太空中。

This is what we call a supernova explosion 文法

這就是我們所說的超新星爆發，

and it will outshine entire galaxies.

它的光芒將蓋過整個星系。

What remains of the star is now a neutron star. 文法

這顆恆星剩下的部分現在就是一顆中子星。

Its mass is around a million times the mass of the Earth,

它的質量大約是地球質量的一百萬倍，

but compressed to an object about 25 km wide.

但卻被壓縮成一個約25公里寬的物體。

It's so dense that the mass of all living humans 文法

它的密度如此之大，以至於所有活著的人類的質量

would fit into 1 cubic centimeter of neutron star matter.

都能塞進1立方公分的中子星物質中。

That's roughly a billion tons in a space the size of a sugar cube.

那大約是一個方糖大小的空間裡裝了十億噸。

Put another way, 表達脈絡

換句話說，

that's Mount Everest in a cup of coffee. 慣用語

那就是把聖母峰塞進一杯咖啡裡。

From the outside,

從外面看，

a neutron star is unbelievably extreme.

中子星極端得令人難以置信。

Its gravity is the strongest outside black holes

它的重力是除黑洞外最強的，

and if it were any denser, it would become one. 文法

如果它的密度再大一點，它就會變成黑洞。

Light is bent around it,

光在它周圍彎曲，

meaning you can see the front and parts of the back. 文法

這意味著你能看到它的正面以及部分的背面。

Their surfaces reach a million degrees Celsius

它們的表面溫度達到一百萬攝氏度，

compared to a measly 6,000 degrees for our sun. 用詞

而我們太陽的表面溫度只有可憐的6000度。

Okay,

好吧，

let's look inside a neutron star. 表達脈絡

讓我們看看中子星的內部。

Although these giant atomic nuclei are stars, 表達脈絡

雖然這些巨大的原子核是恆星，

in many ways they're also like planets

但在很多方面它們也像行星，

with solid crusts over a liquid core.

在液體核心之上著堅硬的外殼。

The crust is extremely hard.

這層外殼非常堅硬。

The outermost layers are made of iron left over from the supernova, 片語動詞

最外層由超新星遺留下來的鐵組成，

squeezed together in a crystal lattice

被擠壓在晶格中，

with a sea of electrons flowing through them. 慣用語

並有電子海在其中流動。

Going deeper,

再往深處去，

gravity squeezes nuclei closer together.

重力將原子核擠壓得更緊。

We find fewer and fewer protons 文法

我們發現質子越來越少，

as most merge to neutrons

因為大多數都融合成中子，

until we reach the base of the crust.

直到我們到達外殼的底部。

Here, nuclei are squeezed together so hard that they start to touch.

在這裡，原子核被擠壓得如此厲害，以至於它們開始相互接觸。

Protons and neutrons rearrange,

質子和中子重新排列，

making long cylinders or sheets,

形成長圓柱體或片狀，

enormous nuclei with millions of protons and neutrons

擁有數百萬質子和中子的巨大原子核，

shaped like spaghetti and lasagna, 文化背景

形狀像義大利麵和千層麵，

which physicists call nuclear pasta.

物理學家稱之為核義大利麵。

Nuclear pasta is so dense that it may be the strongest material in the universe,

核義大利麵的密度極高，它可能是宇宙中最堅硬的物質，

basically unbreakable.

基本上堅不可摧。

Lumps of pasta inside a neutron star can even make mountains,

中子星內部的義大利麵塊甚至可以形成山脈，

at most a few centimeters high, 文法

最多只有幾公分高，

but many times as massive as the Himalayas.

但質量卻比喜馬拉雅山大很多倍。

Eventually, beneath the pasta,

最終，在義大利麵之下，

we reach the core.

我們到達了核心。

We're not really sure what the properties of matter are 文法

我們還不太確定當物質被擠壓得如此厲害時，

when they're squeezed this hard.

它的性質是什麼樣的。

Protons and neutrons might dissolve into an ocean of quarks,

質子和中子可能會溶解成夸克的海洋，

a so-called quark-gluon plasma. 用詞

也就是所謂的夸克-膠子電漿。

Some of those quarks might turn into strange quarks,

其中一些夸克可能會變成奇夸克，

making a sort of strange matter with properties so extreme 片語搭配

形成一種奇異物質，其特性極其極端，

that we made a whole video about it.

以至於我們專門做了一期影片來講解它。

Or maybe they just stay protons and neutrons.

或者它們可能只是保持為質子和中子。

No one knows for sure, 片語搭配

沒有人確切知道，

and that's why we do science.

這就是為什麼我們要進行科學研究。

That's all pretty heavy stuff, 慣用語

這都是些相當沉重的話題，

literally,

字面意義上的沉重，

so let's go back out into space.

所以我們還是回到太空中吧。

When neutron stars first collapse,

當中子星剛坍縮時，

they begin to spin very, very fast,

它們開始旋轉得非常非常快，

like a ballerina pulling her arms in. 表達脈絡

就像芭蕾舞演員把手臂收緊一樣。

Neutron stars are celestial ballerinas

中子星是天體芭蕾舞者，

spinning many times per second.

每秒旋轉很多次。

This creates pulses

這會產生脈衝，

because their magnetic field creates a beam of radio waves,

因為它們的磁場產生了一束無線電波，

which passes every time they spin.

每次旋轉都會掃過一次。

These radio pulsars are the best known type of neutron star. 片語搭配

這些電波脈衝星是中子星中最著名的類型。

About 2,000 are known of in the Milky Way.

銀河系中大約已知有2000個。

These magnetic fields are the strongest in the universe,

這些磁場是宇宙中最強的，

a quadrillion times stronger than Earth's after they're born. 文法

它們誕生後的磁場強度是地球的一千萬億倍。

They're called magnetars until they calm down a little. 片語動詞

在它們稍稍平靜下來之前，它們被稱為磁星。

But the absolute best kind of neutron stars are friends with other neutron stars. 慣用語

但是最棒的中子星，是那些和其他中子星交朋友的。

By radiating away energy as gravitational waves, 文法

通過以重力波的形式輻射掉能量，

ripples in space-time, 慣用語

即時空中的漣漪，

their orbits can decay and they can crash into and kill each other

它們的軌道會衰減，並且它們會碰撞並殺死對方，

in a kilonova explosion that spews out a lot of their guts. 慣用語

在一場千新星爆炸中，噴射出它們的大量內臟。

When they do, 文法

當它們這樣做時，

the conditions become so extreme

條件變得如此極端，

that for a moment heavy nuclei are made again.

以至於重原子核在一瞬間被再次製造出來。

It's not fusion putting nuclei together this time, 文法

這次不是核融合把原子核放在一起，

but heavy neutron-rich matter falling apart and reassembling.

而是富含中子的重物質分崩離析然後重新組裝。

Only very recently,

直到最近，

we've learned that this is probably the origin

我們才知道這很可能是宇宙中，

of most of the heavy elements in the universe,

大多數重元素的起源，

like gold, uranium, and platinum,

比如金、鈾和鉑，

and dozens more.

以及其他幾十種元素。

So then our two neutron stars collapse and become a black hole,

然後我們的兩顆中子星坍縮成一個黑洞，

dying yet again.

再次死亡。

Not only do stars have to die to create elements, 文法

恆星不僅要死一次來創造元素，

they have to die twice.

它們還要死兩次。

Over millions of years,

在幾百萬年的時間裡，

these atoms will mix back into the galaxy,

這些原子將混合回星系中，

but some of them end up in a cloud 片語動詞

但其中一些最終進入了一片雲團，

which gravity pulls together to form stars and planets,

重力將其拉在一起形成恆星和行星，

repeating the cycle.

重複著這個循環。

Our solar system is one example,

我們的太陽系就是一個例子，

and the remains of those neutron stars that came before us

在咱們之前就存在的那些中子星的殘骸，

are all around us.

就在我們周圍。

Our entire technological modern world

我們整個技術發達的現代世界，

was built out of the elements neutron stars made in eons past, 講解

都是由中子星在漫長歲月中製造的元素建立起來的，

sending these atoms on a 13 billion-year journey 文法

這些原子經歷了一場長達130億年的旅程，

to come together and make us and our world.

最終聚集在一起，創造了我們和我們的世界。

And that's pretty cool.

這真是太酷了。