来自太空的死亡——伽马射线暴（Gamma-Ray Bursts）揭秘：英语精读讲义

Imagine if you could gather the energy from every star within a 100 million light years, 語法

想象一下，如果你能收集一亿光年内所有恒星的能量，

from thousands of galaxies,

它们来自数千个星系，

each with billions of stars.

每个星系都有数十亿颗恒星。

Imagine you could take this kind of power

想象一下，你可以利用这种能量

and use it to fire the biggest super weapon in the universe.

来发射宇宙中最大的超级武器。

Imagine the damage you could do.

想象一下你能造成的破坏。

It turns out you don't need to imagine it. 表達脈絡

事实证明，你不需要去想象。

These exist and they're called gamma ray bursts.

这些确实存在，它们被称为伽马射线暴。

But what are these cosmic snipers? 習語

但这些宇宙狙击手究竟是什么？

And what happens if one takes a shot at Earth?

如果它们向地球开了一枪会发生什么？

To understand gamma ray bursts, 表達脈絡

要理解伽马射线暴，

we first have to understand gamma rays.

我们首先必须了解伽马射线。

Gamma rays are electromagnetic radiation,

伽马射线是电磁辐射，

waves which carry energy just like visible light. 表達脈絡

就像可见光一样携带能量的波。

Visible light is a tiny part of the electromagnetic spectrum.

可见光只是电磁波谱的一小部分。

It's the part your eyes can see.

它是你眼睛能看到的那部分。

At lower energies,

在较低能量的一端，

there are radio waves,

有无线电波、

microwaves, and infrared.

微波和红外线。

And at higher energies,

而在较高能量的一端，

ultraviolet, X-rays,

是紫外线、X射线、

and gamma rays.

和伽马射线。

Gamma rays are incredibly powerful.

伽马射线无比强大。

A single gamma ray photon is more energetic than a million visible photons combined.

一个伽马射线光子的能量比一百万个可见光光子加起来还要高。

Their high energy makes gamma rays a form of ionizing radiation,

它们的高能量使伽马射线成为一种电离辐射，

meaning they are energetic enough to break apart atomic bonds. 講解

这意味着它们有足够的能量破坏原子键。

This makes them dangerous to you and me.

这使它们对你我来说都很危险。

Ionizing radiation disrupts the delicate biochemical machinery that keeps us alive,

电离辐射会破坏让我们存活的精密生化机制，

like a 9 mm bullet through a clock. 習語

就像一颗9毫米子弹射穿了钟表一样。

Fortunately,

幸运的是，

on Earth,

在地球上，

the ozone layer blocks gamma rays,

臭氧层阻挡了伽马射线，

filtering them out before they can harm us. 短語動詞

在它们伤害我们之前将其过滤掉。

But if the atmosphere blocks gamma rays from space,

但是，如果大气层阻挡了来自太空的伽马射线，

how were gamma ray bursts or GRBs from space ever discovered?

那么来自太空的伽马射线暴或称 GRB 是如何被发现的呢？

During the Cold War,

在冷战期间，

the USA sent up spy satellites 短語動詞

美国发射了间谍卫星，

which could detect gamma rays from Soviet nuclear tests in space.

这些卫星可以探测到苏联在太空进行核试验时产生的伽马射线。

They didn't see any bombs,

他们没有看到任何核弹，

but they did observe faint bursts coming from space 語法

但却观察到了来自太空的微弱闪发，

lasting only a few seconds.

仅仅持续了几秒钟。

To date, 短語搭配

迄今为止，

this may be the only major scientific discovery made by spy satellites

这可能是间谍卫星取得的唯一一项重大科学发现，

that we know about anyway. 語氣意圖

至少是我们所知的。

Astronomers use telescopes that see different kinds of light to make their discoveries,

天文学家使用能够看到不同种类光线的望远镜来进行发现，

and these spy satellites gave them a new pair of eyes. 習語

而这些间谍卫星给了他们一双新的眼睛。

They were a mystery for 30 years,

这在长达三十年的时间里是个谜，

but eventually we discovered the source of a GRB,

但最终我们发现了一个 GRB 的源头，

a galaxy 6 billion light years away.

一个位于60亿光年外的星系。

If a GRB can be seen from such a distance, 語法

如果在那么远的距离还能看到 GRB，

then it must be incredibly energetic,

那么它一定具有极其巨大的能量，

releasing more energy in a second than the sun will in its entire 10 billion year lifetime, 語法

它在一秒钟内释放的能量比太阳在一百亿年生命周期中释放的还要多，

making GRBs the brightest events in the universe. 語法

这使 GRB 成为宇宙中最明亮的事件。

So,

那么，

where do they come from?

它们从何而来？

GRBs accompany some of the most violent cataclysmic deaths in the universe

GRB 伴随着宇宙中最猛烈的毁灭性死亡

and the birth of black holes.

以及黑洞的诞生。

There are two types of gamma ray burst,

伽马射线暴分为两种，

short and long,

短暴和长暴，

and each has their own source.

各自有着不同的来源。

Long GRBs last about a minute,

长的 GRB 持续大约一分钟，

and scientists think they are produced by supernova

科学家认为它们是由超新星产生的，

when the core of a massive star collapses to become a black hole. 語法

当大质量恒星的核心坍缩成为黑洞时。

Short GRBs last a second

短的 GRB 持续一秒，

and are produced when two neutron stars in a binary merge. 用詞

是由双星系统中的两颗中子星合并时产生的。

Over millions of years,

历经数百万年，

their orbits decay by emitting gravitational waves. 用詞

它们的轨道因为发射引力波而衰减。

Once they're close enough to touch, 語法

一旦它们近到可以接触，

they crash and splash into each other

它们就会碰撞并迸射到彼此身上，

forming a black hole.

形成一个黑洞。

Both supernova and neutron star mergers make the same thing,

超新星和中子星合并都会产生同样的东西，

black holes

即黑洞，

surrounded by a magnetized disc of gas left over from their parent stars. 短語動詞

周围环绕着来自其母星残留气体的磁化盘。

In these environments,

在这些环境中，

the rotation winds up the magnetic field 短語動詞

旋转会卷绕磁场，

which funnels hot jets of particles traveling at maybe the speed of light.

从而将可能以光速行进的热粒子喷流漏斗化。

The gas in this funnel creates two tight jets of high energy gamma rays,

这个漏斗中的气体产生了束缚紧密的高能伽马射线喷流，

like a celestial laser gun. 習語

就像一把天体激光枪。

So,

因此，

unlike other cosmic explosions which spread out and fade, 表達脈絡

不同于其他会扩散并消退的宇宙爆炸，

GRBs stay focused and can be seen from much further.

GRB 保持着聚焦，可以从更远的地方被观测到。

Any more detail would require too much mathematics for a YouTube video. 語氣意圖

再多的细节对于一部 YouTube 视频来说就需要太多数学知识了。

The universe is full of these cosmic snipers,

宇宙中充满了这些宇宙狙击手，

firing blindly and randomly into the dark, 習語

在黑暗中盲目而随机地开火，

and they're hitting us all the time.

它们一直在击中我们。

On average, 短語搭配

平均而言，

we detect one per day.

我们每天会探测到一个。

Fortunately,

幸运的是，

most are harmless.

大多数是无害的。

All the bursts we have detected so far 語法

到目前为止，我们探测到的所有射线暴

originated outside the Milky Way,

都起源于银河系之外，

too far away to hurt us.

距离我们太远，无法造成伤害。

But a nearby GRB could be disastrous.

但如果在附近发生 GRB 可能是灾难性的。

If one goes off within a few light years of us, 短語動詞

如果有一次爆发发生在我们几光年内，

it would totally cook the surface of the Earth, 習語

它将彻底烤熟地球表面，

or at least the half that's facing it.

或者至少是面向它的一半。

But even a more distant GRB could still end life on Earth.

但即使是更遥远的 GRB 仍可能终结地球上的生命。

And it wouldn't need to score a headshot to kill us. 習語

它甚至不需要直接爆头就能杀死我们。

If originating from a few thousand light years away,

如果它起源于几千光年之外，

it would be a 100 light years wide by the time it reaches us,

到达我们这里时，它将达到 100 光年宽，

washing over the solar system like a tidal wave. 習語

像海啸一样冲刷太阳系。

Again,

再说一次，

the ozone layer protects us,

臭氧层保护着我们，

but it's better equipped to handle the trickle of ultraviolet from the sun. 短語搭配

但它更适合应对来自太阳的少量紫外线。

A gamma ray burst would overwhelm it,

伽马射线暴会压垮它，

leaving us exposed to deadly solar radiation. 語法

让我们暴露在致命的太阳辐射中。

Ozone takes years to replenish itself by natural processes, 語法

臭氧层通过自然过程自我补充需要数年时间，

which is more than enough time for the sun to burn the Earth sterile, 語法

这足以让太阳将地球烤得寸草不生，

or at least to kill most complex life.

或至少杀死大部分复杂生命。

In fact,

事实上，

this may have already happened.

这种事可能已经发生过。

A GRB has been suggested as one possible cause of the Ordovician extinction 講解

GRB 被认为是导致奥陶纪物种灭绝的一个可能原因，

450 million years ago

发生在4.5亿年前，

that eradicated almost 85% of all marine species,

灭绝了大约 85% 的海洋物种，

although it's pretty much impossible to prove. 表達脈絡

尽管这几乎不可能被证明。

Gamma ray bursts could even be one reason we don't see life anywhere else in the universe.

伽马射线暴甚至可能是我们在宇宙中其他地方看不到生命的原因之一。

They might be wiping clean huge chunks of it on a regular basis. 講解

它们可能定期抹去宇宙中的大片生命。

It's been suggested that because of GRBs,

有人提出，由于 GRB 的存在，

only 10% of all galaxies might be hospitable to life similar to us. 短語搭配

只有 10% 的星系可能适宜类似我们这样的生命生存。

So,

那么，

are they going to kill us?

它们会杀了我们吗？

Probably not.

可能不会。

In a galaxy like ours,

在像我们这样的星系中，

there may only be one GRB per millennia, 語法

每千年可能只发生一次 GRB，

and to harm us, 語法

并且要伤害我们，

they must be close and directed at us.

它们必须离得很近并且直接对准我们。

But since gamma rays travel at the speed of light,

但由于伽马射线以光速传播，

we won't know one is headed our way until it arrives. 講解

直到它到达，我们才会知道有一个正在向我们飞来。

So,

所以，

there could already be a GRB on its way to kill us all

可能已经有一个 GRB 正在向我们飞来，要杀死我们所有人，

and we won't know it

而我们并不知道，

until it hits us and we're dead.

直到它击中我们，而我们死去。