了解宇宙是如何运行的（2010）

Fiona Harrison runs the NuSTAR mission.
这是第一个目标
Its first target
银河系中心的黑洞
the Black Hole at the center of our galaxy.
NuSTAR能够看到最高能量的X射线
NuSTAR can see the very highest-energy x-rays
能够穿透尘埃和气体
that can penetrate through dust and gas.
使我们能够观察这个黑洞
It enables us to have this view of this Black Hole.
NuSTAR的X射线观测
NuSTAR's x-ray vision
只能看最狂暴的事件
sees only the most violent events.
黑洞大爆发比较少见 但NuSTAR有幸看到
Black Hole tantrums are rare, but NuSTAR got lucky.
我们看到了
We looked.
我们看了大约六小时后
And about six hours after we looked,
我们看到黑洞变亮一百倍
we saw the Black Hole get a hundred times brighter.
那持续多长时间？ 只有几小时
How long did that last? Only a few hours.
然后它就消失 重回沉寂
Then it faded away back into oblivion.
然而这个事件就是我们要找的
But this event was what we were looking for.
我们都大为惊讶
We were all just amazed.
屋子里举杯庆祝
There were cheers in the room.
这是最激动人心的时刻
It was just one of the most exciting moments,
任务刚刚开始 进展也太快了
and so early on in the mission, too.
这是直接证据
It's direct evidence
我们的黑洞还在发挥作用
our Black Hole is still active
还有力量控制银河系
and still has the muscle to control the galaxy.
黑洞的力量显示出来了
The Black Hole's power is revealed
它照亮围绕它旋转的尘埃和气体盘
when it lights up a disk of gas and dust which spins around it.
这些物质以圆盘状围绕黑洞旋转
As this material is swirling around the Black Hole in a disk,
它们互相摩擦
it rubs against each other.
也有磁场和其它力
And there's also magnetic fields and other forces.
所有这些使盘状物加热到极高温度 甚至超过太阳
All of this heats that disk to much hotter, even, than the sun.
NuSTAR检测到围绕黑洞的气体
NuSTAR detects that gas around the Black Hole
正加热到一亿八千万华氏度
is heating up to 180 million degrees fahrenheit.
比太阳表面还热一万八千倍
That's 18,000 times hotter than the surface of the sun.
超热的气体对恒星形成不是好消息
This superheated gas is bad news for star formation.
气体必须冷却 以最终形成恒星
The gas has to get cold in order for it to eventually form stars.
因为气体密度非常非常大
And that's because the gas has to get very, very dense
最终气体会坍塌
so that, eventually, the gas can collapse
坍塌后的内核会发生核聚变
into something that's gonna have nuclear fusion in its core.
所以在黑洞周边的区域
So in regions around Black Holes,
由于太热
because they're so hot,
它们加热周边的气体
they heat up the gas around them.
这会完全限制气体
And that totally limits the ability
转化为恒星的能力
for that gas to turn into stars.
大量的能量被发射出来
Massive amounts of energy are emitted.
这实际上不仅摧毁恒星
And that actually can not only destroy stars,
还会把以后形成恒星的气体吹散
it can blow the gas away that would later on form stars.
恒星制♥造♥工作结束
Star birth shuts down.
在银河系的历史中
Over our galaxy's life,
超大质量黑洞 把气体和尘埃束缚在周围
our supermassive Black Hole drags gas and dust towards it,
构成恒星形成必须的元素
the ingredients needed for star formation.
在初期
In its infancy,
它的力量使气体云聚合在一起
its power slams these gas clouds together,
触发恒星诞生
sparking stars into life.
现在 它极高的温度把气体云吹散
Now, it blows them apart with its extreme heat,
控制了银河系恒星的数量
regulating the population of stars in the galaxy.
星系中心的黑洞有点像阀门
The Black Hole in the center acts a little bit like a valve,
控制银河系恒星的形成
controlling how stars form in the galaxy itself.
黑洞和星系之间是
There is a remarkable symbiotic relationship
明显的共生关系
between Black Holes and galaxies.
黑洞像宇宙的管理者
Black Holes act like cosmic regulators,
在特定时间增加恒星的形成
increasing, at certain times, star formation
控制星系演化的速度
and governing the rate at which galaxies evolve.
我们不知道为什么黑洞能
We're not sure why our Black Hole
阻止某些恒星形成 却触发别的恒星诞生
stops some star formation and sparks others.
我们所知道的
All we do know
就是这规则对我们是必不可少的
is that this regulation might be essential for us.
当制♥造♥恒星时
When it made stars,
黑洞也会有助于创建太阳
the Black Hole might have also helped create our sun.
现在 它限制恒星形成
Now, it limits star formation,
会减少我们地球附近的致命辐射
which could bring lethal radiation near planet earth.
如果我们居住区域有
If we were living in an area where there were
许多年轻恒星和正在爆♥炸♥的超新星
lots of young stars and supernovae blowing up,
这对地球生命来说是个坏消息
that would not be so good for life on earth.
现在适合生命的条件近乎完美
Now the conditions for life are perfect.
眺望我们的夜空 它看起来是不变的、永恒的
Looking up at our night sky, it looks unchanging, eternal.
但在宇宙中 不存在永恒
But in the universe, nothing lasts forever.
银河系正在准备它的下一次巨变
Our galaxy is gearing up for its next big change.
所以未来什么样？
So what does the future hold?
答案是我们将不再是螺旋星系了
The answer is that we won't be a spiral galaxy for much longer.
我们螺旋星系的寿命
Our lifetime as a spiral galaxy
离最终的死亡 大约走完了三分之二
is about two-thirds of the way into its final death throes.
银河系在外面有个大姐姐
The Milky Way has a giant sister out there,
距离太近 令人不舒服
too close for comfort.
她们的姐妹之争令夜空开火
Their sibling rivalry will set the night on fire
宇宙中两个最大的重量级拳手
and pit two of the biggest heavyweights in the cosmos
陷入死亡之战
in a fight to the death.
大约一百三十亿年前
Around 13 billion years ago,
银河系在一个超大质量黑洞周围形成
the Milky Way forms around a supermassive Black Hole.
它逐渐拥有了几千亿颗恒星
it adds hundreds of billions of stars,
逐渐形成一个平的圆盘状 并被塑造为螺旋形
settles into a flat disk and is sculpted into a spiral.
银河系不断的演化
Our galaxy has constantly evolved.
它的未来也与其它星系一样
Its future is no different.
它将变得狂暴
And it's going to get violent.
晚上出去 仰望夜空
Go out tonight and look at the night sky
用双筒望远镜
with a pair of binoculars,
你可以看到仙女座星系
and you can see the Andromeda galaxy.
这是我们的未来
That is our future.
也许四十亿年或五十亿年后
Perhaps 4 or 5 billion years from now,
我们会和我们隔壁的邻居发生大碰撞
we will be on a collision course with our next-door neighbor.
这可能像是一场敌对的大接收
And it could be like a hostile takeover.
仙女座直冲我们而来
Andromeda is heading straight for us.
当然碰撞不是新鲜事
Collisions are, of course, nothing new.
在银河系初期
In its infancy,
我们靠碰撞和吞吃其它星系成长壮大
our galaxy grew by colliding and eating other galaxies.
但这一次 有所不同
But this time, it's different.
当初的校园霸王 即将遇上对手
The original schoolyard bully is going to meet its match.
银河系总是比周遭强
The Milky Way has always been the biggest thing around.
任何跑到附近的小星系
So any little Dwarf galaxy that's gotten near
都会被拆散
has gotten torn apart,
银河系总是保持正常运行
but the Milky Way just keeps right on going.
现在有另一个真正的大家伙
Now, there's another really big galaxy
正直冲我们而来
that's actually headed right for us right now.
这是仙女座 另一张圆盘
That's Andromeda. It's another disk.
当两张大圆盘跑到一起
And when these two big disks come together,
就会一个盘子也没有
there's not gonna be a disk left.
两个盘子没有胜利者
Neither of those disks is gonna win.
当碰撞靠近时
As the collision nears,
我们的夜空会完全改变
our night sky will change completely.
今天如果你放眼望去 夜空背景确实是黑的
Today, if you look out when it's really dark,
你看到大的银河带
you see the big band of the Milky Way.
真是美不胜收
It's a beautiful thing.
几十亿年后
A few billion years from now,
你看到的不是一条恒星带
what you would see is not just one band of stars,
另一条恒星带像这样交叉过来
but another band of stars that crisscrosses like this.
当它靠近
As it nears,
仙女座在我们的夜空变得越来越大
Andromeda grows larger and larger in our sky.
最后 两个星系彼此撞击
Finally, the galaxies smash into one another.
恒星被从原来轨道上撕下来
Stars are torn from their orbits.
实际上恒星不会碰撞
The stars don't actually collide.
恒星太小
Stars are extremely small
和它们之间的空间比起来
compared to the space in-between them.
但对气体云来说 情况发生改变
But that's not true for gas clouds.
气体云太大