了解宇宙是如何运行的（2010）

How the Universe Works S08E08

Part 2 Jan. 30, 2022, 2:59 p.m.

initially at near the speed
of light.
当产生这样的喷流时它们可以
And as they do so,
they can wreak havoc
造成严重的破坏或塑造
or sculpt the evolution
of the galaxy
喷流所传播星系的进化
that
they're propagating through.
人马座a星的喷流
Narrator:
Sagittarius a-star's jets
将气体喷出星系
blasted gas out of the galaxy,
形成了我们所看到的费米气泡
creating the scars we see
as the fermi bubbles.
造成这些喷射的东西似乎已经关闭了
Now, whatever caused those jets
seems to have turned off.
它不再发生了
It's not happening anymore
我们看到了它们的残余物
and we're seeing sort
of the leftovers of them.
但显然这是一个迹象
But this is clearly a sign
表明在过去几百万年的某个时候
that sometime in the past
few million years,
我们星系中心的黑洞，人马座a星
the black hole
in the center of our galaxy,
正在积极地吞噬周围的物质
sagittarius a-star, was actively
feeding on material around it.
有物质掉进去，然后被喷射出来
Material was falling into it
and blasting out this stuff.
“喷气引擎”在他们身后留下了毁灭
Narrator: The jets left
destruction in their wake.
♪
它们也可能影响了我们整个星系的发展
they may have also affected
the growth of our entire galaxy.
银河系中心的这些结构非常重要
These structures at the center
of our galaxy are important
因为它们既可以阻止恒星的形成
because they can either
shut off star formation
也可以触发恒星的形成
or they can trigger
star formation.
特伦布雷:当这些喷流穿过星系时
Tremblay: As those jets
propagate through the galaxy,
它们会堆积气体
they pile up gas
然后这些气体会被触发形成恒星
and that gas can be then
triggered into star formation.
但这些喷流也可以向周围环境
But these jets can also impart
so much heat or energy feedback
传递大量的热量或能量，从而阻止恒星的形成
into the environment that
they prevent star formation.
所以黑洞在很多方面指挥着一个管弦乐队
So black holes in many ways
conduct an orchestra,
指导或指挥恒星何时能形成，何时不能形成
instructing or dictating
when stars can and cannot form.
♪
在银河系的中心
narrator:
In the center of the milky way,
恒星的形成率似乎很低
star-formation rates seem low.
“喷气引擎”可能要为此负责
The jets could be responsible.
但在2017年，阿尔玛望远镜发现
But in 2017,
the alma telescope discovered
变化即将到来
that change is coming.
泰勒:所以阿尔玛实际上能够
Thaller: So alma's actually been
able to peer in
窥视到我们星系的中心
to the heart of our galaxy
看到在所有这些破坏附近
and see that near
all this destruction,
实际上可能有新一代恒星正在形成
there might actually be a new
generation of stars forming.
今天，我们平静的超大质量黑洞
Narrator: Today, our calm
supermassive black hole
可能在帮助核心的恒星形成
could be helping
star formation in the core.
但是费米气泡可能是
But the fermi bubbles could be
evidence of a time
人马座a星停止恒星形成的证据
when sagittarius a-star
shut down star formation.
超大质量黑洞在未来
Could the supermassive
black hole
会咆哮着重生吗？
roar back to life in the future?
人马座的a星可以通过
Tremblay: Sagittarius a-star
could roar back to life
向它倾倒一些气体来恢复生命
by just dumping some gas
onto it.
在我们星系的中心有很多气体
And there's a lot of gas
at the center of our galaxy
它们可能会漫游到
and it could wander into
the proximity
人马座a星附近
of sagittarius a-star
最终落在事件的视界上
and ultimately fall
onto the event horizon
从而使核心被照亮
and that would light it up.
如果人马座a星吸收了足够的气体……
Narrator: If sagittarius a-star
eats enough gas...
……它可以使星系中的恒星停止形成
...It could shut down
star formation in the galaxy
达数百万年
for millions of years.
♪
它也可能释放出有可能袭击地球的
it could also give off x-rays
and gamma rays
X射线和伽马射线
that may hit the earth.
萨特:值得庆幸的是，我们中心的超大质量黑洞
Sutter: Thankfully, our central
supermassive black hole
非常安静，这种巨大的进食事件
is pretty quiet
and massive feeding events,
以及巨大的能量事件非常非常罕见
massive energy events
are very, very rare.
我们不必太多担心
We don't necessarily
have much to worry about.
人马座a星重塑了我们的星系
Narrator: Sagittarius a-star
has reshaped our galaxy.
如果我们想在宇宙中生存
If we want to survive
in the universe,
我们需要更多地了解这个巨大的黑洞
we need to know more about
this monster black hole.
视界望远镜的任务就是要做到这一点
The event horizon telescope
is on a mission to do just that.
问题是它能成功吗？
Question is can it succeed?
♪
银河系的中心是一个
narrator:
The center of the milky way
超大质量黑洞——
is home to a supermassive
black hole,
人马座a星
sagittarius a-star.
至少我们认为是这样的
At least we think it is.
我们从未直接看到过
We've never seen
the supermassive
超大质量黑洞
black hole directly.
但我们也看到过恒星绕着核心飞行
But we have seen stars
racing around the core.
菲利平科:恒星围绕银河系中心
Filippenko:
The speeds of the stars
旋转的速度表明
zipping around the center
of our milky way galaxy
那里有一个质量非常大
indicate that there's
something very massive
非常紧凑的东西
and very compact there,
实际上，它的质量是太阳的400万倍
indeed, 4 million times
as massive as our sun
体积却小于太阳系
in a volume smaller
than that of our solar system.
它基本上是个黑洞
It's got to be
a black hole basically.
通过测量银河系中心
Narrator: By measuring
the orbits of stars
恒星的轨道……
in our galaxy center...
……我们估计人马座a星
...We estimate
that sagittarius a-star
比我们的太阳宽100多倍
is over a hundred times
wider than our sun.
尽管黑洞很大，但它是隐藏的
But despite its size,
the black hole is hidden.
特伦布雷:观测黑洞最直接的
Tremblay:
One of the immediate challenges
挑战之一是
of actually observing
black holes
实际上它们不发光，你看不到它们
is the fact that they don't emit
light and so you can't see them.
对吧？所以我们从来没有见过黑洞
Right? So we've never
actually seen a black hole.
我们只看到了黑洞周围的物质
We've only seen the stuff
around a black hole
或者说我们看到了黑洞
or we have seen the effects
that that black hole
对周围环境的影响
imparts on its ambient
surroundings.
这就是视界望远镜的由来
Narrator: That's where the event
horizon telescope came in.
它的目标是拍摄人马座a星
Its goal was to photograph
sagittarius a-star,
不是黑洞本身，而是它的阴影
not the black hole itself,
but its shadow.