了解宇宙是如何运行的（2010）

How the Universe Works S06E05

Part 5 Dec. 22, 2021, 7:22 p.m.

within distant galaxy clusters like hydra a.
一个大问题是
One big question is,
是什么把气体放在那里的？
what could've put that gas there？
是什么使这种气体温度如此之高
What could have made this gas so hot
以至于它能喷发到离星系很远的地方呢？
that it's able to puff out so far from the galaxy？
一种可能性是，这是由银河系历史上的
One possibility is that this was driven by an active phase
一个活跃阶段驱动的
in our galaxy's history.
在遥远的银河系中心
Far away, in the heart of our galaxy,
隐藏在气体和云层之下的是一个巨大的……
hidden by gas and clouds, lies a giant...
一个超大质量黑洞叫做人马座A星
A supermassive black hole called Sagittarius a-star.
现在,它是安静的
Now, it's quiet.
它是死了还是睡着了？
Is it dead or just sleeping？
唯一能在银河系上下制♥造♥出
The only thing that could have created
这些巨大物质的是
these vast lobes of material above and below the milky way
从银河系核心流出的巨大喷流
are giant jets streaming out of the core of our galaxy.
嗯，这听起来是不是很像类星体？
Well, doesn't that sound a lot like a quasar？
但与 hydra a (海德拉 a)不同的是
But unlike hydra a, the expelled gas
这些喷出的气体并非来自数亿年前
doesn't date from hundreds of millions of years ago.
这些喷流是在过去的600万年里爆发了
These were blown out within the last 6 million years.
我们在宇宙中看到的几乎所有类星体都在遥远的地方
Almost all quasars we see are in the distant universe,
这意味着它们都在遥远的过去
which means they're in the distant past.
但这是最近的活动
But here we have recent activity.
就在600万年前，我们星系中心的黑洞还在进食
Just 6 million years ago, our central black hole was feeding.
没有人真正预料到这一点
No one really expected that because,
因为从我们记事起，我们一直认为
for as long as we can remember, we've thought about
我们的银河系是静止的
our milky way galaxy as being quiescent,
也就是说不会吃得太多
that is to say not really eating too much,
有点像一个饮食中的黑洞
sort of like a black hole on a diet.
一定是什么东西破坏了它的饮食
Something must have broken its diet.
也许是一群不幸的恒星离得太近了
Maybe an unfortunate group of stars strayed too close.
不管是什么方式
Whatever the delivery method,
这颗沉睡的人马座A星狼吞虎咽地
the sleeping Sagittarius a-star gorged
吃了一顿新的饭，然后爆♥炸♥性地醒来了
on its new meal and woke up explosively.
它的喷流从星系中喷射出去了
Its jets blasted over a trillion trillion trillion tons of gas
超过十万亿吨♥的气体
out of the galaxy.
幸运的是，我们的黑洞
Thankfully, our black hole
比典型的类星体要小得多
is much smaller than a typical quasar.
这只是一次小小的爆发
This was only a small outburst,
但我们沉睡的巨人
but it's possible our sleeping giant
可能会再次醒来
could wake up again, much bigger
比以前更大更危险
and much more dangerous than ever before.
总有一天会有这样的事发生
There's something coming up that means that one day,
当你走到外面，看着夜空
you may walk outside, look at the night sky
你会发现类星体启动了
and realize the quasar has turned on.
我们知道星系碰撞
We know quasars can be triggered
可以触发类星体
by galactic collisions,
我们也知道有一个星系正朝我们走来
and we know a galaxy is heading our way.
公共安全公告……银河系
Public safety announcement... The milky way galaxy
正在与仙女座星系发生碰撞
is on a collision course with Andromeda.
它以每秒70英里的速度向我们移♥动♥
It's traveling at us at about 70 miles a second,
大约40亿年之后
and in about 4 billion years,
这两个星系将发生碰撞
these two galaxies are going to collide.
两个星系都有超大质量黑洞
Both of us have supermassive black holes.
我们的质量是太阳的四五百万倍
Ours is 4 or 5 million times the mass of the sun.
而仙女座星系的黑洞要大20倍
And Andromeda's black hole is 20 times larger.
最终，这些黑洞
Eventually, those black holes
将开始围绕彼此旋转
will start spiraling around each other,
它们注定要合并
and they're destined to merge.
新的黑洞将比人马座a星
The new black hole will be much bigger
要大得多
than Sagittarius a-star,
而这个超巨星将有新的气体需要消耗
and this supergiant will have a fresh load of gas to consume.
这将是银河系的一次难以置信的爆♥炸♥
This will be an incredible explosion for the milky way,
甚至可能是银河系
maybe even the biggest explosion
整个生命周期中最大的一次爆♥炸♥
it's ever had in its whole life cycle.
类星体的诞生的爆♥炸♥可能比
A quasar could be born far bigger
我们之前经历过的任何爆♥炸♥都要大得多
than anything we have experienced before.
在合并的混乱中，我们的太阳系可能会迁移
In the chaos of the merger, our solar system could migrate,
向星系核心移♥动♥，向类星体移♥动♥
moving closer to the galaxy's core, closer to the quasar.
我们不仅能亲眼目睹星系的碰撞
We will have a front-row seat to not only colliding galaxies,
还能看到更惊人更可怕的事情
but in fact, something even more amazing and terrifying,
类星体被启动了
a quasar being switched on.
我们离得越近，场面越壮观
The closer we are, the bigger the spectacle.
它看起来就像天空中一个明亮的光源
It would look like a single bright source in the sky,
几乎就像第二个太阳
almost like a second sun.
伴随着美丽风景的将是难以置信的热量
Along with the beauty will be incredible heat,
类星体风，也许，甚至喷射
quasar winds, and, perhaps, even jets.
这一切对地球意味着什么？
What will all this mean for Earth？
大气会被剥离
The atmosphere is going to be stripped away.
海洋要沸腾了
Oceans are going to boil.
也许你脚下的石头会融化
Maybe the rock under your feet will melt.
我的意思是，我们所说的
I mean, we're talking about
是巨大的能量
a tremendous amount of energy here.
地球上绝对不会有生命
There would absolutely be no life on Earth.
这颗新点燃的类星体可能能量非常巨大
The newly ignited quasar may be so energetic
会从银河系中心
it blasts trillions of tons of gas
喷发出数万亿吨♥气体
out of the milky way.
在未来，即使是恒星和行星的基本成分
Even the basic ingredients for future stars and planets
也可能面临风险
could be at risk.
那是恒星形成的地方，也是行星形成的地方
That's where stars form, and that's where planets form,
所以如果把所有的正常物质
and so if you kick all the normal matter
都踢出星系
out of the galaxies,
就不再有恒星，行星
you no longer get stars and planets
也不再有人类和文明
and humans and civilizations.
我觉得这不是个好主意
That doesn't sound like such a good idea to me.
类星体具有可怕的破坏力
With their terrible destructive force,
对星系来说似乎是个坏消息
quasars seem like bad news for galaxies.
但我们现在发现了它们的另一面
But we are now discovering there's another side to them.
类星体释放了那么多的能量
Quasars are putting out so much energy,
它们似乎对它们的环境造成了非常大的破坏
they appear to be so disruptive to their environment,
但也有可能，没有它们，我们就不会在这里
but it could be that, without them, we wouldn't be here.
类星体有着巨大的能量
For all their ferocious power,
它们可能是宇宙的终极创造者
quasars might be the ultimate cosmic creators.
类星体释放出难以想象的能量
Kicking out unimaginable power,
可能会在其所在的环境中造成混乱
quasars can cause chaos in their local environment,
但这可能对一个健康的星系
but it's possible that this might be essential
至关重要
for a healthy galaxy.
它甚至可能为生命创造条件
It might even create the conditions for life.
我们发现类星体虽然具有破坏性
We're discovering that for all their destructive properties,
但也有创造性的一面
quasars also have a creative side,
所以很有可能我们周围的宇宙
so it very well may be that the universe we see around us
就是由类星体塑造的
was shaped by quasars.
恒星是星系的本质
Stars are the essence of a galaxy,
但一切都是有节制的
but everything in moderation.
恒星太多可能会造成问题
Too many stars can actually be a problem.
有很多新恒星形成
Having a lot of new star formation
是一件好事
is kind of a good thing,
但太多就不好了
but too much of it can be a bad thing.
新恒星诞生时，很多都是
When new stars are born, many of them are going to be
又热又大的蓝色恒星
hot, large, blue stars,
但最终，这些年轻的热恒星会开始死亡
but eventually, those young, hot stars are going to start to die,
当它们死亡时，它们会以超新星的形式
and when they do, they're going to explode violently
剧烈爆♥炸♥
as supernovae.
会有新的黑洞出现
There will be new black holes.
也会有新喷流
There will be jets.
会有震动穿过
There will be shocks that actually go
星系的气体
through the gas of the galaxy.
所有这些，实际上，会把星系给杀死
All of that is, effectively, killing the galaxy.
新恒星形成的大爆发
Large bursts of star formation
会使星系剧烈而混乱
make the galaxy violent and chaotic.
恒星和行星会被超新星和黑洞的
Stars and planets are wiped out by intense radiation
强烈辐射摧毁