永恒黑暗前的最后之光 —— 白矮星与黑矮星：英语精读讲义

Humans can survive in this universe as long as we have an energy source. 語法

只要有能量源，人类就能在这个宇宙中生存下去。

Unfortunately, the universe will die.

不幸的是，宇宙将会走向死亡。

It will happen slowly over many billions of years,

这是一个漫长的过程，需要数十亿年，

but it will happen.

但它终究会发生。

On a universal time scale,

在宇宙的时间尺度上，

stars like our sun will be gone in no time. 習語

像太阳这样的恒星很快就会消亡。

Luckily, there are places that will exist practically forever from a human perspective. 短語搭配

幸运的是，从人类的角度来看，有些地方几乎可以永远存在。

The corpses of dead stars,

那就是死亡恒星的尸体——

white dwarfs.

白矮星。

They could be humanity's last home right before the death of the universe.

它们可能成为宇宙死亡前人类最后的家园。

What are these strange things?

这些奇怪的东西究竟是什么？

And what happens when they finally die?

当它们最终死亡时又会发生什么？

How long stars live varies drastically,

恒星的寿命差异极大，

depending on how massive they are. 語法

取决于它们的质量。

For example,

例如，

really massive stars burn hot and fast,

质量极大的恒星燃烧得又热又快，

dying violently in supernovae a few million years after birth.

在诞生几百万年后就会在超新星爆发中猛烈地死去。

But they're the exception.

但它们只是例外。

97% of all stars will end their existence as white dwarfs.

宇宙中97%的恒星最终都会变成白矮星。

There are two ways this can happen.

这通常有两种方式。

Small stars,

质量较小的恒星，

so called red dwarfs,

即所谓的红矮星，

burn out over trillions of years 短語動詞

会在数万亿年的时间里慢慢燃烧，

until they eventually quietly turn into white dwarfs. 短語動詞

直到最终静静地变成白矮星。

Medium-sized stars like our sun are more interesting.

像太阳这样的中等质量恒星则更有趣。

Imagine the sun as a huge pressure cooker 表達脈絡

把太阳想象成一个巨大的高压锅，

that fuses hydrogen into helium in its core

在其核心通过引力

through its gravity.

将氢聚变成氦。

The fusion of elements releases extreme amounts of energy

元素的聚变释放出极大的能量，

that pushes outwards and stabilizes the star,

这些能量向外推挤，稳定了恒星，

keeping it in a delicate balance. 短語搭配

使其保持着微妙的平衡。

When the sun is old,

当太阳老去时，

the hydrogen in the core is exhausted,

核心的氢被耗尽，

and the sun will begin to burn helium into heavier elements.

太阳便开始将氦聚变成更重的元素。

While doing so, 表達脈絡

在这个过程中，

it will shed its outer layers. 用詞

它会褪去它的外层。

When this process is over,

当这个过程结束时，

more than half of the sun's mass will be lost into space

太阳一半以上的质量都将散落到太空中，

as a spectacular planetary nebula

形成一个壮观的行星状星云，

millions of kilometers across. 語法

跨度达数百万公里。

What remains will be its former core. 語法

留下的将是它曾经的核心。

A white dwarf is born,

一颗白矮星诞生了，

a star corpse.

一具恒星的尸体。

While its former self was about 100 times its diameter, 語法

它曾经的直径是现在的100倍左右，

now it's only about as big as Earth,

现在只有地球那么大，

but still with about half of its former mass.

但依然保留着过去一半的质量。

This means it's extremely dense.

这意味着它的密度极高。

A teaspoon of white dwarf is about as massive as a car. 語法

一茶匙白矮星物质的质量大约相当于一辆汽车。

Its surface gravity is over 100,000 times higher than Earth's. 語法

其表面引力是地球的10万倍以上。

If you tried to land on it, 語法

如果你试图在上面登陆，

you'd immediately be compressed into a steaming puddle.

你会立刻被压成一滩冒着热气的肉泥。

Life around a white dwarf is very unlikely,

在白矮星周围存在生命的希望十分渺茫，

but possible.

但也并非不可能。

Most of them that exist now were former stars that,

现存的大多数白矮星都是曾经死去的恒星，

well, died, 語氣意圖

嗯，死去了，

which probably ruined any planets they once had.

这可能毁掉了它们曾经拥有的所有行星。

But that's not all. 表達脈絡

但还不止这些。

Since they are so small,

因为它们太小了，

a planet would need to orbit them about 75 times closer 語法

行星需要在一个比地球离太阳近大约75倍的轨道上绕行，

than Earth is to the sun to have liquid water.

才能拥有液态水。

This proximity has ups and downs. 習語

这种近距离有利也有弊。

For one, 表達脈絡

首先，

it would tidally lock the planet,

它会潮汐锁定行星，

giving it a permanent day and permanent night.

让它有一面永远是白天，一面永远是黑夜。

At the edges of these day and night zones,

在昼夜交界处，

life could be possible.

生命可能是存在的。

But white dwarfs have a very stable energy output,

此外白矮星的能量输出非常稳定，

so they might actually be safer to live around 語法

所以在它们周围生活实际上可能更安全，

than many red dwarfs.

甚至比许多红矮星还要安全。

This is still speculation at this point, 短語搭配

虽然目前这还只是推测，

but if we could find a white dwarf

但如果我们能找到一颗白矮星，

with the right conditions to settle around,

并且条件适合定居，

we could have a home for many billions of years.

我们就能拥有一个可以居住数十亿年的家园。

But why do they shine so much longer than other star types?

可是为什么它们发光的时间比其他类型的恒星长那么多？

White dwarfs are very,

白矮星非常、

very hot,

非常热，

up to 40 times hotter than our sun, 語法

温度最高可达我们太阳的40倍，

ranking among the hottest objects in the universe.

是宇宙中最热的天体之一。

But they are not incredibly active.

但它们并不极其活跃。

All the heat inside of them is trapped

它们内部所有的热量都被困住了，

and has nowhere to go. 短語搭配

无处可去。

Only on its outer layer can it escape into space. 語法

只有在外层，热量才能散发到太空中。

But space is mostly empty,

但是太空大部分是真空的，

so heat can't be transferred by conduction.

所以热量不能通过传导来传递。

The only way energy can escape is by radiation. 語法

能量逃逸的唯一方式是辐射。

This is so inefficient 語法

这种方式效率极低，

that white dwarfs will take trillions of years to cool down, 短語動詞

以至于白矮星需要数万亿年的时间才能冷却下来，

which may make them humanity's last refuge. 習語

这可能使它们成为人类最后的避难所。

They might be the last sources of light and energy

它们可能是这个垂死宇宙中

in a dying universe.

最后的光和能量来源。

According to some estimates, 短語搭配

根据一些估算，

white dwarfs might shine as long as 100 billion billion years, 用詞

白矮星可能会发光长达1000亿亿年，

10 billion times longer than the universe has existed.

比宇宙目前存在的历史长100亿倍。

So far into the future

在那么遥远的未来，

that no regular stars will shine anymore.

任何常规的恒星都不会再发光了。

Galaxies will have evaporated. 語法

星系也将消散。

And only then will the first white dwarf 語法

直到那时，第一颗白矮星才会

turn into the first black dwarf.

变成第一颗黑矮星。

When this happens,

当这件事发生时，

the last hope for life will die off. 短語動詞

生命最后的希望也将破灭。

Black dwarfs will be inactive spheres with no energy left to give.

黑矮星将变成没有能量可以释放的不活跃球体。

Still massive enough to kill you if you get too close.

尽管它们仍然具有极大的质量，靠得太近仍会丧命。

So cold that they'll be near the coldest possible temperature 語法

它们极度寒冷，接近于宇宙中的

in the universe.

绝对最低温度。

So dark that they are practically invisible.

它们极其黑暗，几乎不可见。

The universe will enter its last stage,

宇宙将进入它的最后阶段：

heat death, 文化背景

热寂，

which will leave the universe unrecognizable.

这将使宇宙变得面目全非。

An absolutely dark and cold graveyard

一个绝对黑暗和寒冷的坟墓，

with black holes and black dwarfs

里面充满了黑洞和黑矮星，

scattered over trillions of light years.

散布在数万亿光年的空间里。

We don't know for sure 短語搭配

我们无法确定

what will happen with black dwarfs in the end.

黑矮星最终会发生什么。

If the proton,

如果质子——

one of the fundamental parts of atoms,

这个原子的基本组成部分之一——

has a limited lifespan,

有有限的寿命，

black dwarfs will slowly evaporate over many trillions of years.

那么黑矮星将在数万亿年的时间里慢慢蒸发。

If the proton does not decay,

如果质子不衰变，

black dwarfs will probably turn into spheres of pure ion

黑矮星可能会通过量子隧穿效应

via quantum tunneling over a time span

变成纯离子球，这需要经过一段

so obscenely gigantic that calling it forever is okay. 語法

漫长得离谱的时间，用“永恒”来形容也毫不夸张。

These ion spheres will then travel completely alone

这些离子球将在黑暗的宇宙中

through a dark universe.

孤独地穿行。

Nothing new will happen anymore.

再也不会有任何新鲜事发生。

Forever.

永远。

While this may sound kind of dark,

虽然这听起来有些阴郁，

this is so far away that for our purposes today,

但这离我们太遥远了，就目前的状况而言，

it might as well not happen at all. 短語搭配

它完全等同于不会发生。

It doesn't matter what happens in a billion trillion years. 語法

万亿亿年后发生什么并不重要。

Right now,

就在当下，

we happen to exist at an excellent time, 短語搭配

我们碰巧存在于一个绝佳的时代，

able to be in awe about a universe filled with endless stars

能够敬畏这个充满无尽星辰、

and light and planets

光芒和行星的宇宙，

and enough time to visit them one day.

并且我们有足够的时间在未来去造访它们。

Our music is finally available on Spotify and iTunes.

我们的音乐终于在 Spotify 和 iTunes 上架了。

It's composed by our good friends at Epic Mountain,

它由我们的好朋友 Epic Mountain 创作，

two guys with a studio who make music for a living. 短語搭配

两个有工作室、靠做音乐谋生的小伙子。

You can check them out here 短語動詞

你可以在这里查看他们的作品，

and follow them on Facebook and Twitter.

并在 Facebook 和 Twitter 上关注他们。

And if you like our videos,

如果你喜欢我们的视频，

please consider supporting us on Patreon.

请考虑在 Patreon 上支持我们。

It really would be extremely helpful.

这真的会对我们有极大的帮助。

If you need an excuse to delay work a little bit longer,

如果你需要一个借口再拖延一会儿工作，

here's a playlist with more space videos.

这里有一个包含更多太空视频的播放列表。