中子星——除了黑洞外最极端的存在：英语精读讲义

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

中子星是宇宙中最极端、最狂暴的事物之一。

Giant atomic nuclei only a few kilometers in diameter,

直径只有几公里的巨大原子核，

but as massive as stars.

但质量却和恒星相当。

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

它们的存在归功于某种宏伟事物的死亡。

Stars exist because of a fragile balance.

恒星之所以存在，是因为一种脆弱的平衡。

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

成千上万亿兆吨的高温等离子体

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

被引力向内拉扯，并以极大的力量将物质挤压在一起，导致原子核发生聚变。

Hydrogen fuses into helium.

氢聚变成氦。

This releases energy,

这释放出能量，

which pushes against gravity and tries to escape.

对抗引力并试图向外逃逸。

As long as this balance exists, 語法

只要这种平衡存在，

stars are pretty stable.

恒星就非常稳定。

Eventually, the hydrogen will be exhausted.

最终，氢会被耗尽。

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

像我们太阳这样的中等恒星会经历一个巨大的阶段，

where they burn helium into carbon and oxygen

在这个阶段，它们将氦燃烧成碳和氧，

before they eventually turn into white dwarfs.

然后最终变成白矮星。

But in stars many times the mass of our sun,

但在质量是我们太阳许多倍的恒星中，

things get interesting when the helium is exhausted.

当氦耗尽时，事情就变得有趣了。

For a moment,

有那么一瞬间，

the balance of pressure and radiation tips 習語

压力和辐射的平衡被打破，

and gravity wins,

引力占据上风，

squeezing the star tighter than before.

以前所未有的力度挤压恒星。

The core burns hotter and faster

核心燃烧得更热、更快，

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

而恒星的外层则膨胀数百倍，

fusing heavier and heavier elements. 語法

聚变出越来越重的元素。

Carbon burns to neon in centuries,

碳在几个世纪内燃烧成氖，

neon to oxygen in a year,

氖在一年内变成氧，

oxygen to silicon in months,

氧在几个月内变成硅，

and silicon to iron in a day.

而硅在一天内变成铁。

And then, death.

然后，死亡。

Iron is nuclear ash.

铁是核灰烬。

It has no energy to give and cannot be fused.

它没有能量可释放，也不能发生聚变。

The fusion suddenly stops and the balance ends.

聚变突然停止，平衡就此终结。

Without the outward pressure from fusion, 語法

没有了聚变向外施加的压力，

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

核心被上方恒星的巨大重量压碎。

What happens now is awesome and scary.

接下来发生的事情既令人敬畏又令人恐惧。

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

像电子和质子这样的粒子真的不想彼此靠近。

But the pressure of the collapsing star is so great

但是坍缩恒星的压力是如此之大，

that electrons and protons fuse into neutrons,

以至于电子和质子融合成中子，

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

然后它们被挤压得像原子核中一样紧密。

An iron ball the size of the Earth 表達脈絡

一个地球大小的铁球

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

被挤压成一个城市大小、纯粹由核物质组成的球体。

But not just the core, the whole star implodes,

但不仅仅是核心，整颗恒星都会向内发生内爆，

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

引力以光速的25%将外层向内拉扯。

This implosion bounces off the iron core,

这种内爆在铁芯上反弹，

producing a shock wave that explodes outwards

产生向外爆炸的冲击波，

and catapults the rest of the star into space. 用詞

并将恒星的其余部分弹射到太空中。

This is what we call a supernova explosion 語法

这就是我们所说的超新星爆发，

and it will outshine entire galaxies.

它的光芒将盖过整个星系。

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

这颗恒星剩下的部分现在就是一颗中子星。

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

它的质量大约是地球质量的一百万倍，

but compressed to an object about 25 km wide.

但却被压缩成一个约25公里宽的物体。

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

它的密度如此之大，以至于所有活着的人类的质量

would fit into 1 cubic centimeter of neutron star matter.

都能塞进1立方厘米的中子星物质中。

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

那大约是一个方糖大小的空间里装了十亿吨。

Put another way, 表達脈絡

换句话说，

that's Mount Everest in a cup of coffee. 習語

那就是把珠穆朗玛峰塞进一杯咖啡里。

From the outside,

从外面看，

a neutron star is unbelievably extreme.

中子星极端得令人难以置信。

Its gravity is the strongest outside black holes

它的引力是除黑洞外最强的，

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

如果它的密度再大一点，它就会变成黑洞。

Light is bent around it,

光在它周围弯曲，

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

这意味着你能看到它的正面以及部分的背面。

Their surfaces reach a million degrees Celsius

它们的表面温度达到一百万摄氏度，

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

而我们太阳的表面温度只有可怜的6000度。

Okay,

好吧，

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

让我们看看中子星的内部。

Although these giant atomic nuclei are stars, 表達脈絡

虽然这些巨大的原子核是恒星，

in many ways they're also like planets

但在很多方面它们也像行星，

with solid crusts over a liquid core.

在液体核心之上有着坚硬的外壳。

The crust is extremely hard.

这层外壳非常坚硬。

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

最外层由超新星遗留下来的铁组成，

squeezed together in a crystal lattice

被挤压在晶格中，

with a sea of electrons flowing through them. 習語

并有电子海在其中流动。

Going deeper,

再往深处去，

gravity squeezes nuclei closer together.

引力将原子核挤压得更紧。

We find fewer and fewer protons 語法

我们发现质子越来越少，

as most merge to neutrons

因为大多数都融合成中子，

until we reach the base of the crust.

直到我们到达外壳的底部。

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

在这里，原子核被挤压得如此厉害，以至于它们开始相互接触。

Protons and neutrons rearrange,

质子和中子重新排列，

making long cylinders or sheets,

形成长圆柱体或片状，

enormous nuclei with millions of protons and neutrons

拥有数百万质子和中子的巨大原子核，

shaped like spaghetti and lasagna, 文化背景

形状像意大利面和千层面，

which physicists call nuclear pasta.

物理学家称之为核意面。

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

核意面的密度极高，它可能是宇宙中最坚硬的物质，

basically unbreakable.

基本上坚不可摧。

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

中子星内部的意面块甚至可以形成山脉，

at most a few centimeters high, 語法

最多只有几厘米高，

but many times as massive as the Himalayas.

但质量却比喜马拉雅山大很多倍。

Eventually, beneath the pasta,

最终，在意面之下，

we reach the core.

我们到达了核心。

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

我们还不太确定当物质被挤压得如此厉害时，

when they're squeezed this hard.

它的性质是什么样的。

Protons and neutrons might dissolve into an ocean of quarks,

质子和中子可能会溶解成夸克的海洋，

a so-called quark-gluon plasma. 用詞

也就是所谓的夸克-胶子等离子体。

Some of those quarks might turn into strange quarks,

其中一些夸克可能会变成奇异夸克，

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

形成一种奇异物质，其特性极其极端，

that we made a whole video about it.

以至于我们专门做了一期视频来讲解它。

Or maybe they just stay protons and neutrons.

或者它们可能只是保持为质子和中子。

No one knows for sure, 短語搭配

没有人确切知道，

and that's why we do science.

这就是为什么我们要进行科学研究。

That's all pretty heavy stuff, 習語

这都是些相当沉重的话题，

literally,

字面意义上的沉重，

so let's go back out into space.

所以我们还是回到太空中吧。

When neutron stars first collapse,

当中子星刚坍缩时，

they begin to spin very, very fast,

它们开始旋转得非常非常快，

like a ballerina pulling her arms in. 表達脈絡

就像芭蕾舞演员把手臂收紧一样。

Neutron stars are celestial ballerinas

中子星是天体芭蕾舞者，

spinning many times per second.

每秒旋转很多次。

This creates pulses

这会产生脉冲，

because their magnetic field creates a beam of radio waves,

因为它们的磁场产生了一束无线电波，

which passes every time they spin.

每次旋转都会扫过一次。

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

这些射电脉冲星是中子星中最著名的类型。

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

银河系中大约已知有2000个。

These magnetic fields are the strongest in the universe,

这些磁场是宇宙中最强的，

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

它们诞生后的磁场强度是地球的一千万亿倍。

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

在它们稍稍平静下来之前，它们被称为磁星。

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

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, 語法

通过以引力波的形式辐射掉能量，

ripples in space-time, 習語

即时空中的涟漪，

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

它们的轨道会衰减，并且它们会碰撞并杀死对方，

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

在一场千新星爆炸中，喷射出它们的大量内脏。

When they do, 語法

当它们这样做时，

the conditions become so extreme

条件变得如此极端，

that for a moment heavy nuclei are made again.

以至于重原子核在一瞬间被再次制造出来。

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

这次不是聚变把原子核放在一起，

but heavy neutron-rich matter falling apart and reassembling.

而是富含中子的重物质分崩离析然后重新组装。

Only very recently,

直到最近，

we've learned that this is probably the origin

我们才知道这很可能是宇宙中，

of most of the heavy elements in the universe,

大多数重元素的起源，

like gold, uranium, and platinum,

比如金、铀和铂，

and dozens more.

以及其他几十种元素。

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

然后我们的两颗中子星坍缩成一个黑洞，

dying yet again.

再次死亡。

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

恒星不仅要死一次来创造元素，

they have to die twice.

它们还要死两次。

Over millions of years,

在几百万年的时间里，

these atoms will mix back into the galaxy,

这些原子将混合回星系中，

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

但其中一些最终进入了一片云团，

which gravity pulls together to form stars and planets,

引力将其拉在一起形成恒星和行星，

repeating the cycle.

重复着这个循环。

Our solar system is one example,

我们的太阳系就是一个例子，

and the remains of those neutron stars that came before us

在咱们之前就存在的那些中子星的残骸，

are all around us.

就在我们周围。

Our entire technological modern world

我们整个技术发达的现代世界，

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

都是由中子星在漫长岁月中制造的元素建立起来的，

sending these atoms on a 13 billion-year journey 語法

这些原子经历了一场长达130亿年的旅程，

to come together and make us and our world.

最终聚集在一起，创造了我们和我们的世界。

And that's pretty cool.

这真是太酷了。