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太空死光——解释伽马射线爆发

Death From Space — Gamma-Ray Bursts Explained

试着想象 你能从数百万光年范围内的每颗恒星收集能量
Imagine if you could gather the energy from every star within a hundred million light years.
这意味着上千个星系 每个都包括数十亿颗恒星
From thousands of galaxies, each with billions of stars.
试着想象 你能使用这种能量 来驱动宇宙中最大的超级武器
Imagine, you could take this kind of power, and use it to fire the biggest super-weapon in the universe.
想想看你的破坏力
Imagine the damage you could do.
事实是 根本无需想象
It turns out, you don’t need to imagine it.
它们是真实存在的 叫做伽马射线暴
These exist, and they’re called gamma ray bursts.
但是 这些宇宙狙击手究竟是什么?
But what are these cosmic snipers?
如果其中之一击中地球 会发生什么?
And what happens if one takes a shot at Earth?
要了解伽马射线暴 我们必须首先了解伽马射线
To understand gamma ray bursts, we first have to understand gamma rays.
伽马射线是一种电磁辐射 — 像可见光那样的能量波
Gamma rays are electromagnetic radiation – waves which carry energy just like visible light.
可见光是电磁波频谱的很小一部分:是人类肉眼可见的部分
Visible light is a tiny part of the electromagnetic spectrum: it’s the part your eyes can see.
低频能量电磁波有无线电波 微波和红外线
At lower energies, there are radio waves, microwaves and infrared.
高频能量电磁波则包括:红外线 X射线和伽马射线
And at higher energies: ultraviolet, x-rays and gamma rays.
伽马射线拥有惊人的能量
Gamma rays are incredibly powerful.
一个伽马射线光子 比一百万个可见光子加起来的能量还要大
A single gamma ray photon, is more energetic than a million visible photons combined.
伽马射线的高能特性使其成为一种电离辐射
Their high energy makes gamma rays a form of ionizing radiation.
这意味着他们有足够的能量来打破原子键
Meaning they are energetic enough, to break apart atomic bonds.
所以对你我来说十分危险
This makes them dangerous to you and me.
电离辐射会破坏我们脆弱的生化机制 导致死亡
Ionizing radiation disrupts the delicate biochemical machinery that keeps us alive,
如同击穿钟表的9毫米子弹
like a 9mm bullet through a clock.
幸运地是 地球的臭氧层能阻挡伽马射线。在伽马射线伤害到我们以前将其过滤
Fortunately, on Earth, the ozone layer blocks gamma rays. Filtering them out before they can harm us.
但如果大气层完全挡住了来自太空的伽马射线
But if the atmosphere blocks gamma rays from space,
人们又是如何发现伽马射线暴的呢?
how were gamma ray bursts (or GRBs) from space ever discovered?
冷战期间
During the Cold War,
美国发射的间谍卫星 可以侦测到苏联太空核试验所发出的伽马射线
the USA sent up spy satellites, which could detect gamma rays from Soviet nuclear tests in space.
他们没发现核弹 而是观测到来自太空的微弱伽马射线暴
They didn’t see any bombs, but they did observe faint bursts coming from space,
持续时间只有几秒
lasting only a few seconds.
迄今为止 这可能是间谍卫星做出的唯一一个重大科学发现(我们也就知道这一个)
To date, this may be the only major scientific discovery made by spy satellites (that we know about anyway).
天文学家们通过望远镜观测不同光线来寻找发现
Astronomers use telescopes see different kinds of light to make their discoveries.
间谍卫星则赋予了他们新的双目
And these spy satellites gave them a new pair of eyes.
在这之后的30年里 伽马射线暴始终保持着神秘色彩 但最终
They were a mystery for thirty years but eventually,
人们发现了一次伽马射线暴的源头:在一个距我们六十亿光年远的星系
we discovered the source of a GRB: a galaxy six billion light years away.
如果伽马射线暴能从这么远的距离被观测到 它一定具有惊人的能量
If a GRB can be seen from such a distance, then it must be incredibly energetic.
伽马射线暴在一秒内释放的能量 比太阳在一百亿年的寿命中还要多
Releasing more energy in a second than the sun will, in its entire ten billion year lifetime.
使得伽马射线暴成为宇宙中最耀眼的风景
Making GRBs, the brightest events in the universe.
那么 他们从哪来?
So, where do they come from?
伽马射线暴常伴随着宇宙中最剧烈 最灾难性的死亡
GRBs, accompany some of the most violent, cataclysmic deaths in the universe,
以及黑洞的诞生
and the birth of black holes.
有两种伽马射线暴:
There are two types of gamma ray bursts:
短暴和长暴 来源不同
short and long, and each has their own source.
长伽马射线暴能持续一分钟左右 科学家认为由超新星产生:
Long GRBs last about a minute, and scientist think they are produced by supernova:
当一颗巨大恒星的核心塌陷成黑洞
when the core of a massive star collapses to become a black hole.
短伽马射线暴持续一秒 由两颗中子星的双星合并产生
Short GRBs last a second, and are produced when two neutron stars in a binary merge.
数百万年的时间里 两颗中子星的轨道被双星系统释放的引力波不断侵蚀
Over millions of years, their orbits decay by emmiting gravitational waves.
一旦达到足够近的距离 两颗中子星相互撞击 形成黑洞
Once they are close enough to touch, they crash and splash into each other, forming a black hole.
但不论超新星还是中子星 他们合并后产生的是同样的东西:
Both supernova and neutron star mergers the same thing:
黑洞 被原星体剩下的气体形成的磁环所围绕
black holes, surrounded by a magnetized disc of gas left over from their parent stars.
在这样的环境下 旋转给磁场加速 喷射出炽热的离子流
In these environments, the rotation winds up the magnetic field, which funnels hot jets of particles,
其行进速度接近光速
traveling at nearly the speed of light.
汇集处的气体创造出两道高能伽马射线
The gas in this funnel creates two tight jets of high energy gamma rays,
就像太空中的激光枪
like a celestial laser gun.
因此 其他宇宙爆炸会逐渐消散
So unlike other cosmic explosions, which spread out and fade,
而伽马射线暴则是集中的 从很远的距离也能观测的到
GRBs say focused, and can been seen from much further.
其他细节则需要数学进行解释 对You Tube视频来说过于复杂了
Any more detail would require too much mathematics for a YouTube video.
宇宙中充满了类似的狙击手 毫无规律地向幽暗处盲射
The universe is full of these cosmic snipers, firing blindly and randomly into the dark,
他们还经常打中我们
and they’re hitting us all the time.
我们每天平均能侦测到一次。幸运的是 大部分是无害的
On average, we detect one per day. Fortunately, most are harmless.
目前我们已观测到的各种爆发 都来自银河系外部
All the bursts we have detected so far, originated outside the Milky Way,
距离地球太远 伤不到我们
too far away to hurt us.
但是 擦肩而过的伽马射线暴则可能是灾难性的
But a nearby GRB could be disastrous,
若有伽马射线暴在距地球几光年内通过 就可能烧焦地球表面
if one goes off within a few light years of us, it would totally cook the surface of the Earth.
或者至少 面向射线暴的半面
Or at least, the half that’s facing it.
但即便距离更远些的伽马射线暴也可能终结地球上所有的生命
But even a more distant GRB could still end life on Earth.
还不需要直接命中就能杀死我们
And it wouldn’t need to score a head-shot to kill us.
如果从数千光年外发射
If originating from a few thousand light years away,
伽马射线暴到达地球时会扩展到数百光年宽
it would be a hundred light years wide by the time it reaches us,
然后像海浪一般冲刷过太阳系
washing over the Solar System like a tidal wave.
臭氧层的确能保护我们 但它主要针对的是来自太阳的紫外线照射
Again, the ozone layer protects us, but it’s better equipped to handle the trickle of ultraviolet from the sun.
伽马射线暴将破坏臭氧层 使人们暴露在致命的太阳辐射之下
A gamma ray burst would overwhelm it, leaving us exposed to deadly solar radiation.
通过自然过程 臭氧层需要数年时间自我修复
Ozone takes years to replenish itself by natural processes,
与此同时 太阳光早已把地球照射成了不毛之地
which is more than enough time for the sun to burn the Earth sterile.
或者 杀死大部分复杂生命体
Or at least, to kill most complex life.
事实上 这一切可能发生过
In fact, this may have already happened.
四亿五千万年前 发生了奥陶纪大灭绝 伽马射线暴是可能的原因之一
A GRB has been suggested as one possible cause of the Ordovician extinction 450 million years ago,
最终导致几乎85%的海洋生物灭绝
that eradicated almost 85% of all marine species.
虽然几乎无法证明
Although it’s pretty much impossible to prove.
伽马射线暴还可能是我们尚未在宇宙中发现其他生命的原因之一
Gamma ray bursts could even be one reason we don’t see life anywhere else in the universe.
他们可能有规律地清除了大部分的生命
They might be wiping clean huge chucks of it, on a regular basis.
有人推测 由于伽马射线暴 宇宙中只有10%的星系适合生命生存
It’s been suggested, that because of GRBs, only 10% of all galaxies might be hospitable to life,
对我们也一样
similar to us.
那么 伽马射线暴会消灭人类吗?
So, are they going to kill us?
可能不会
Probably not.
在我们的星系中 每一千年可能遇到一次伽马射线暴
In a galaxy like ours, there may only be one GRB per millennia.
要伤害我们 伽马射线暴必须足够近而且朝向地球
And to harm us, they must be close and directed at us.
但既然伽马射线是以光速行进的 我们只有在看见伽马射线的时候 才知道它是朝地球的方向射来
But since gamma rays travel at the speed of light, we won’t know when it’s headed our way until it arrives.
因此 可能有伽马射线暴在前来毁灭我们的路上 但人们并不知情 直到伽马射线暴击中地球
So, there could already be a GRB on its way to kill us all, and we won’t know it, until it hits us,
然后我们就都挂了
and we’re dead.
本视频由squarespace.com/nutshell赞助
This video was sponsored by squarespace.com/nutshell
从天而降的死忙之光可能随时到来
Death from the sky could come around any second.
也许 就是现在!
Maybe, even now!
所以不要浪费时间了
So you don’t have any time to waste.
学习架设网站 作品集或者博客通常费时又费力
Learning to set up a website, portfolio or blog is usually hard and time consuming.
但有了Squarespace就不一样了
Not so with Squarespace though.
它能用简单易懂的工具帮你快速构建网页
They let you set up a page with easily understandable tools, very quickly,
完全不用学习网页设计的知识
and without any knowledge of web design.
你可以输入代码 “NUTSHELL” 节省10%并支持Kurzgesagt
You can use the code “NUTSHELL” to save 10% and support Kurzgesagt.
Squarespace一直是非常棒的赞助者 向他们展示你的爱心吧
Squarespace have been a great sponsor, so give them some love.
你也可以在Patreon上直接支持我们 或者在这里购买Kurzgesagt相关商品:
You can support us directly at Patreon or get Kurzgesagt merch here:
感谢帮助
it really helps.
在接下去的几个月 我们还会制作更多关于灾难性毁灭事件的视频
Over the next few months, we’d like to make more videos about cataclysmic destructive events,
因为 实话实说 这个话题非常有料
because, honestly, it’s a lot of fun to make these.
如果你有想了解的审判日情节
If you have any ideas about what kind of doomsday scenario you’d like to learn about,
可以在评论中注明
let us know in the comments.
如果你还想再杀点时间 请观看相关视频
And if you need to kill a little more time now, here are few related videos.
或者…
Or maybe…
就现在!
NOW!

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