宇宙时空之旅（2014）

Cosmos: A SpaceTime Odyssey S01E04

Part 5 April 25, 2021, 12:39 p.m.

当巨大的恒星耗尽了自身的核燃料
When giant stars exhaust their nuclear fuel,
就无法保持自己温度
they can no longer stay hot enough
来抵抗自身向内的引力作用
to fend off the inward pull of their own gravity.
质量最大的恒星坍缩成黑暗
The most massive stars collapse into darkness,
只剩下自己的重力场
leaving only their gravity behind.
这个黑洞吞噬了一颗超大质量恒星
This black hole enshrouds the shrunken corpse
坍缩的残骸
of a supergiant star.
恒星自身已经萎缩成
The star itself has shriveled into something
比这片黑暗更小的物体
even smaller than this darkness,
直径只有六十四千米
only 6♥4♥ kilometers wide.
这是有史以来发现的第一个黑洞
This is the first black hole ever discovered--
天鹅座X-1
Cygnus X-1.
我们究竟是如何发现
How did we on Earth ever find something
如此渺小黑暗和遥远的物体呢
so small and dark and far away?
我们通过另一种光线看到它 X射线
We looked at it in another kind of light. X-rays.
在X射线中我们无法看到这颗蓝色的恒星
In X-ray light, we lost sight of the blue star
因为它的表面温度只有三万度
because its surface is a tepid 30,000 degrees.
但是黑洞周围围绕的盘状气体
But the disk of gas around the black hole
由于一亿度的温度放出耀眼的X射线
glowed brilliantly in X-rays at 100 million degrees.
威廉·赫歇尔的研究指出
As William Herschel discovered,
许多恒星和相距不远的伴星
many stars have close companions
组成一个双星系统
forming a binary star system
但如果其中一颗恒星非常巨大
but if one member of such a pair is enormous
而另一颗是致密星
and the other is compact,
较小的一颗会吸收和耗尽
the smaller star can drain and consume the atmosphere
较大恒星的大气
of its larger sibling.
这种不公平的关系可以延续百万年
This neurotic relationship can last for millions of years.
较大恒星的大气会因虹吸效应
The atmosphere of the larger star was being siphoned onto
形成一个发光的炽热吸积盘围绕着黑洞
a glowing hot accretion disk that revolves around
并螺旋着进入其中
and spirals into a black hole.
不可抗拒的引力加速了蓝色恒星的气体
The overwhelming gravity was accelerating the blue star's gas
进入死亡漩涡
into a death spiral,
穿越时空的边界
crossing the spacetime boundary,
从此消失不见
never to be seen again.
分离开黑洞
The fateful boundary
和宇宙中其他一切的关键边界
that separates a black hole from the rest of the universe
叫做事件视界
is called an event horizon.
在我们看来盘上的物质
From our point of view, the substance in the disk
在靠近事件视界时会减速
slows down as it approaches the event horizon,
不会真正到达视界
never quite reaching it.
但是如果你乘着旋转的气体
But if you were riding on that spiraling gas--
我不推荐你这么做
and i don't advise it--
你就能在几秒钟内穿越事件视界
you would sail past the event horizon in a matter of seconds
到达一个有去无回
into the undiscovered country
无法被探索的国度
from which no traveller returns.
我们所有探索过许多星系的中心地带
We have searched the hearts of dozens of galaxies,
每一个星系我们都找到了一个超大质量黑洞
and in every case, we have found a super-massive black hole.
银河系也不例外
Our own galaxy is no exception.
离银河系中心最近的恒星
The stars nearest the center of our galaxy
以超过每小时四千万千米的速度公转
whip around at more than 40 million kilometers an hour.
什么让它们运行得这么快
What could make them move so fast?
唯一符合逻辑的解释
The only logical explanation
就是一个四百万倍太阳质量的天体
is that something with the mass of four million suns
存在于银河系中心
lies at the center.
这个有太阳四百万倍质量的天体发出的光在哪
So where's the blazing light of four million suns?
既然我们无法看到
Since we can't see it,
就说明它被黑洞吞噬了
it must be imprisoned inside a black hole.
地球是远处在安全距离之外的
Earth is far enough away to be perfectly safe.
但其他星球可能不这么走运了
Other worlds might not be so lucky.
如果你能通过危险的旅途
If you somehow survived the perilous journey
成功穿越视界
across the event horizon,
你就能够溯古追今
you'd be able to look back out
看着整个宇宙的未来历史
and see the entire future history of the universe
在你眼前徐徐展开
unfold before your eyes.
怎么做到的
How?
因为当四维时空被黑洞的巨大引力
Because when spacetime is warped
所扭曲的时候
by the extreme gravity of a black hole,
时间也被伸展到了极限
time is stretched to the limit.
那你面前将出现怎样的光景
But what would be in front of you?
当我们到达那里我要提前警告你
Before we go there, i should warn you
我们正在进入一个未知的科学领域
that we're entering uncharted scientific territory.
我们只知道将会有还未被发现的物理定律
For all we know, there may be undiscovered laws of physics
在黑洞的中心控制一切
that govern events at the center of a black hole.
但是在下一个爱因斯坦出现之前
But until the next Einstein comes along,
我们来假想一个思维实验
let's perform a thought experiment.
这就是约翰·米歇尔在十八世纪
That's how John Michell first imagined dark stars
第一次想象暗星
in the 18th century,
和爱因斯坦开始构思相对
and how Einstein conceived of his theory of rela...
父亲您相信灵魂吗
Father, do you believe in ghosts?
不我信的并非人类的灵魂
Oh, no, not in the human kind of ghosts.
不完全不是
No, not at all.
但是抬头看我的孩子
But look up, my boy,
你可以看见灵魂充满了天空
and see a sky full of them.
如果你能在通向黑洞的旅程中幸存下来
If you could survive the trip into a black hole,
你可能会在宇宙中的另一处时空出现
you might emerge in another place and time in our own universe,
不受相对论的基本规律控制
circumventing the first commandment of relativity...
汝不可超越光速行之
Thou shalt not travel faster than light.
没有东西可以超越光速穿过空间
Nothing can move through space faster than light.
但是空间不仅仅是虚无
But space is not mere emptiness.
它可以被伸展收缩和变形
Its properties can stretch and shrink and can be deformed.
当这发生的时候时间也变形了
And when that happens, time is deformed, too.
爱因斯坦发现空间和时间
Einstein discovered that space and time
只是同一物体的两个方面即四维时空
are just two aspects of the same thing, spacetime.
四维时空本身可以变形
Spacetime itself can deform enough
足够以任何速度带着你去任何地方
to carry you anywhere at any speed.
黑洞可能同样也是穿梭宇宙的隧♥道♥
Black holes may very well be tunnels through the universe.
在这样的星际交通系统上
On this intergalactic subway system,
你能去到宇宙时空最遥远的地方
you could travel to the farthest reaches of spacetime,
甚至也可以达到更为奇妙的地方
or you might arrive in someplace even more amazing.
我们可能发现自己处于一个完全不同的宇宙
We might find ourselves in an altogether different universe.
但是浩大的宇宙是怎样浓缩进一个黑洞里
But how can a whole universe fit inside of a black hole,
而它只是我们宇宙小小的一部分呢
which is only a small part of our universe?
这是时空带给我们的另一个小把戏
It's another magic trick of spacetime.
黑洞巨大的引力
The phenomenal gravity of a black hole
可以扭曲整个宇宙的时空塞入黑洞
can warp the space of an entire universe inside it.
地球上的重力可能足够拽住我们
Our local gravity might be a drag to us,
但是和一个坍缩恒星内部相比
but it's really feeble compared
实在是太过微弱了
with what goes on inside a collapsed star.
据我们所知
As far as we know,
当一个巨型恒星坍缩成一个黑洞
when a giant star collapses to make a black hole,
中心地带超大的密度和压强接近大爆♥炸♥
the extreme density and pressure at the center mimic the big bang,
而大爆♥炸♥开创了我们的宇宙
which gave rise to our universe.
在黑洞内部的宇宙
And a universe inside a black hole
可能产生属于自己的黑洞
might give rise to its own black holes.
那些黑洞又可以创造其他宇宙
And those could lead to other universes.
这可能就是我们宇宙的真正形态
Maybe that's how our cosmos came to be.
我们只知道
For all we know,
如果你想知道黑洞内部真实的样子
if you want to see what it's like inside a black hole,
看看周围就可以了
just look around you.
威廉·赫歇尔继续探索太阳
William Herschel went on to discover that the Sun
和它的行星在银河中的运行
and its planets are moving through the milky way.
那他的儿子约翰呢
And whatever became of his son John?
他成长为一名出色的科学家
He grew up to become a great scientist.
他继续了父亲的深空观测
His deep-space observations built on those of his father
他建立了我们今天所用的标准星系表
to become the basis for the standard catalog of galaxies we use today.
当威廉的身体每况愈下时
When William was in failing health,
约翰彻夜陪着他
John stayed with him through the long nights at his telescope
用望远镜观测恒星
to help him sweep the stars.
当他父亲去世时约翰写了他的墓志铭
And when his father died, John wrote his epitaph...
"他打破了天堂之墙"
"he broke through the walls of heaven."