宇宙时空之旅（2014）

Cosmos: A SpaceTime Odyssey S01E08

Part 4 April 25, 2021, 12:40 p.m.

这时太阳唯一存在过的证据
The kernel of light at the center
就是它的光之内核
will be the only part of the Sun that endures,
这是一颗还会在接下来的一千亿年里
a white dwarf star that will go on shining dimly
继续发出黯淡光芒的白矮星
for another 100 billion years.
当遥远未来的生命路过
Will the beings of a distant future,
这颗恒星的残骸之时
sailing past this wreck of a star,
会不会了解它曾经抚育过的世界和生命
have any idea of the life and worlds that it once warmed?
普通恒星梦幻般的裹尸布转瞬即逝
The psychedelic death shrouds of ordinary stars are fleeting,
通常只存在几万年的时间
lasting only tens of thousands of years
之后就会消散回到星际气体和尘埃中
before dissipating in the interstellar gas and dust
而新生命也会从此诞生
from which the new stars will be born.
双星系统中的恒星命运则有所不同
The stars in a binary star system can have a different fate.
夜空中最亮的天狼星
Sirius, the brightest star in the night sky,
有一颗很暗很暗的伴星
has a very faint stellar companion--
一颗白矮星
a white dwarf.
这颗白矮星曾经与太阳很像
It was once a Sun-like star.
当天狼星燃尽自己的核燃料变成一颗红巨星
Someday, when Sirius runs out of fuel and becomes a red giant,
它会把自己的物质转移到那颗白矮星上
it will shed its substance onto the white dwarf.
这颗伴星的强大引力将会吸引那些气体
The intense gravity of the companion will attract that gas,
使它们形成一个漩涡盘
pulling it into a spiraling disk.
当较大的恒星上的气体
When the gas from the larger star
落到白矮星表面的时候
falls onto the surface of the white dwarf,
它们将会引发核爆♥炸♥
it will trigger nuclear explosions.
最大的爆发将会释放出
The greatest burst will release
十万倍太阳的能量
100,000 times more energy than the Sun.
这种爆发的恒星被称作"新星"
Each one of those star bursts is called a "Nova,"
来自于拉丁文"新"
from the Latin for "New."
对于十五倍太阳质量的恒星
A star about 15 times as massive as the Sun,
比如像猎户座右脚处的
one like Rigel, the blue supergiant
参宿七一样的蓝超巨星
that forms the right foot of Orion,
它的命运又是有所不同的
has a different fate in store.
电子的压力就完全无法阻止它的塌缩过程
Its collapse will not be stopped by the pressure of electrons.
这种恒星会继续向内塌缩
The star will keep falling in on itself,
直到恒星内部的原子核由于过度拥挤
until its nuclei become so overcrowded
产生对抗引力的压力
that they push back.
参宿七会收缩到自身的十万分之一
Rigel will shrink down about 100,000 times,
直到原子核靠得非常紧密
until there's no space left between the nuclei
以至于无法再继续收缩
and it can shrink no more.
到那时
At that point,
它会引发一个更强大的核爆♥炸♥ 一个超新星
it ignites a more powerful nuclear reaction, a supernova.
绝大多数恒星演化
Most stellar evolution
都长达千万或者百亿年
takes millions or billions of years.
但是能引发超新星的内核塌缩
But the interior collapse that triggers a supernova explosion
却只持续仅仅几秒钟
takes only seconds.
爆发之后剩下的是一个称作脉冲星的
What remains will be an atomic nucleus
急速自转的中子星
the size of a small city--
它就是一个原子核大小跟一座小城市差不多
a rapidly rotating neutron star called a pulsar.
但对于超过三十倍太阳质量的恒星来说
But for a star more than 30 times as massive as the Sun--
比如猎户座腰带处的参宿二
a star like Alnilam, in Orion's Belt--
这种塌缩就完全没办法被阻止了
there will be no stopping its collapse.
在几百万年之后
In a few million years,
当参宿二也耗光了自己的燃料
when Alnilam runs out of fuel,
它也会超新星爆发
it, too, will go supernova.
参宿二向内塌缩的内核
The imploding core of Alnilam
质量如此巨大以至于原子核之间的核力
will be so massive that not even nuclear forces
都没有办法阻止它的塌缩
will be strong enough to hold off its collapse.
没有任何东西能承受如此大的引力
Nothing can withstand such gravity.
而这种恒星的宿命是不可思议的
And such a star has an astonishing destiny.
它会不停地塌缩
It will continues to collapse,
直至过了一个被称作"视界"的
crossing a boundary in space-time
时空边界
called the "Event horizon,"
我们看不到边界内的任何东西
beyond which we cannot see.
当它跨过那道边界
When it traverses that frontier,
这颗恒星就彻底从视线中消失了
the star will vanish completely from sight.
它会进到一个黑洞中
It will be inside a black hole,
这地方的引力强到没有任何东西
a place where gravity is so strong that nothing,
就算是光也无法逃脱
not even light, can escape.
对于另一种更罕见的恒星来说
But there's an even more dramatic fate
它们的命运更有戏剧性
that awaits a rare kind of star.
这种星在银河系中就有一颗
There's one of them in our galaxy.
它是如此的不稳定以至于当它爆发时
It's so unstable that when it goes,
它不会简单地成为新星或者超新星
it won't become a mere nova or supernova.
一种更惨烈的结局在等待着它它会成为
It'll become something far more catastrophic...
超超新星
a hypernova.
这种爆发在我们有生之年就可能发生
And it could happen in our lifetime.
澳洲内陆可以说是地球上
There are few places on Earth to get a better view of the night sky
最适合观测星空的地方
than the Australian Outback.
没有建筑物
No buildings,
没有汽车没有街灯这里什么都没有
no cars, streetlights, nothing out here;
只有无垠的星空和星光
just lots of starlight...
还有偶尔露脸的袋鼠
and the occasional kangaroo.
在这里看银河的话风景一定不会差
You can get a particularly good view of the Milky Way from down here.
银河系的中心高高地升在天上
The center of our galaxy rises high in the sky,
那跨越天际的弧形就好像夜空的脊梁
and it arches across the heavens like the backbone of night.
我们住在一个螺旋星系中
We live in a spiral galaxy.
当我们仰望银河系的时候
And when we look at the Milky Way,
看到的其实是漩涡盘中数百亿的恒星的星光
we're seeing light from billions of stars in its spiral disk.
而在这美好的夜空下
And under this beautiful dark sky,
你会发现其实银河系并不是一条均匀的光带
you can see that the Milky Way isn't a uniform band of light.
它有昏暗的区域截断了星光
There are dark patches, breaks in the starlight.
这些昏暗的区域是由星际尘埃产生的
Those dark patches are caused by interstellar dust.
这种尘埃会阻挡星光而尘埃又有很多很多
The dust blocks the starlight, and there's lots of it.
大部分的文明仰望星空时
Most cultures looked up at the stars
都会把星空中的点连接起来
and connected the dots
在天空中组成一些熟悉的图案
to form familiar images in the sky.
这就是星座
Constellations.
但是澳大利亚的原住民们
But the Aboriginal people of Australia
却在沿着银河系延伸的黑暗中发现了一个图案
saw a pattern in the darkness running through the Milky Way.
他们看到了澳洲大♥陆♥的一种特有大鸟鸸鹋
They saw an emu, a large bird native to this continent.
并不是在繁星中而是在无星处
Not in the stars, but in the absence of stars.
想看夜空的话有太多种方法
There are so many ways to look at the night sky.
从人类诞生开始我们已经仰望星空百万年
For a million years or more, we've watched the sky.
而这当中发生了很多事情
And a lot's happened in that time.
超新星在银河系中差不多一个世纪发生一次
Supernova explode in our galaxy about once a century.
如果我们把这百万年凝视星空的时间
If we could compress all those nights of stargazing
凝结到一分钟里
into a single minute,
这就是我们能看到的
this is what we would see.
现在如果假设我们的眼睛就是望远镜
Now, if our eyes were telescopes,
假设它们是大如马车轮的接收光的桶
if they were light buckets as big as wagon wheels
同时我们的视力也不局限于单一类型的光
and our vision was not limited to just one kind of light,
那这就是我们能看到的银河系
then this is the Milky Way we would see.
这是近红外波段的银河系
A galaxy in near-infrared light
在由无数恒星组成的背景之上
with streaming tendrils of dust
超新星爆发正在将尘埃
hurled outward by those exploding supernovas,
像蜿蜒的藤蔓一样抛射出去
silhouetted against a backdrop of countless stars.
在银河系的另一部分
About 7,500 light-years away,
大概七千五百光年之外
in another part of our galaxy,
在难以置信的尺度之上正发生着惊人的剧变
there is a place of upheaval on an inconceivable scale.
这里是船底座星云
This is the Carina Nebula.
一个造星机器
A star-making machine.
要横穿这块星云就算是光也要跑五十年
It takes a ray of light 50 years to cross it.
这里诞生的巨型恒星
The titanic stars born here
正在用强烈的紫外辐射
sear the surrounding gas and dust
灼烧着周围的气体和尘埃
with their fierce ultraviolet radiation.
当一个巨大的恒星死亡时
When a massive star dies,
它会把自己炸成碎片
it blows itself to smithereens.
它的物质被抛射至无垠的空间中
Its substance is propelled across the vastness
等星光去唤起待引力去聚集
to be stirred by starlight and gathered up by gravity.
星归尘尘归星
Stars to dust and dust to stars.
在这个宇宙中没有什么会被浪费
In the cosmos, nothing is wasted.