恒星七纪（2012）

就是残骸
is a remnant.
恒星即将进入它一生的
The star is ready to enter the next
下一个神秘的阶段
enigmatic phase of its life.
白矮星曾让科学家困惑了好几十年
White Dwarfs baffled astronomers for decades.
首要的问题就是找到它们
The first problem was finding them.
其实它们就藏在我们眼前
It turned out they'd been hidden in plain sight.
只是我们需要一个更大的望远镜去找到它们
We just needed a bigger telescope to see them.
北半球冬季的夜空中
The winter sky in the northern hemisphere
有着许多神奇的星座
brings a set of fantastic constellations.
比如这个 大犬星座
Like this one, Canis Major.
大犬星座有着夜空中最亮的恒星
Canis Major contains the brightest star in the night sky.
叫做天狼星
It's called Sirius.
天狼星 弗朗西斯科拍摄
它是颗漂亮的恒星 也叫做大犬星
A lovely star, also known as the Dog Star.
在十九世纪
And it was discovered in the 19th century,
随着望远镜质量的不断提高
when the telescopes were really, really high quality
科学家发现天狼星有一颗伴星
that Sirius has a companion,
被主星明亮的光辉
a very faint companion that is lost
掩盖了的黯淡的伴星
in the glare of the very bright star.
天狼星A
天狼星B 发现于1862年
这颗大犬星的伴星被戏称为"小狗"
This tiny companion to the bright Dog Star was dubbed the Pup.
在1922年
And by 1922,
这种新型的恒星有了正式命名
this new type of star had an official classification.
叫做白矮星
It was called a White Dwarf.
但是科学家们并不在意如何命名
But naming it was the least of scientists' problems.
当比较了它的大小和质量时
When they compared its size to its mass,
却得到了意想不到的结果
something extraordinary emerged.
它的密度比地球上的任何东西都要大
It was denser than anything on Earth,
比之前想象的任何东西都要大
denser than anything previously imagined.
它们根本就是种不该存在的恒星
They were a type of star that shouldn't exist.
它的核聚变已经停止 剩下的不过是残骸
The burnt-out remains of one whose fusion has stopped.
燃料都已耗尽了 它们是如何发光的呢
Their fuel is exhausted, so how can they still shine?
这个疑团困扰了约翰·埃利斯教授很久
Mysteries that have long intrigued Professor John Ellis.
纵观其一生 恒星都在通过
Throughout their lives, stars make their energy
让轻原子核聚变成更重的原子核来产生能量
by fusing together light nuclei to make heavier ones.
约翰·埃利斯教授
伦敦国王学院 理论物理学家
它们先是把氢聚变成氦
They start off with hydrogen and they make helium,
然后它们继续聚变氦核
then they go on to fuse together helium
产生碳和氧
to make carbon and oxygen.
随着时间推移
And as time goes on,
它们消耗了越来越多的燃料
they burn up more and more of this fuel
最终就像汽车一样 没油了
until, eventually, it's like a car, you run out of gas.
随着氦燃烧的结束
With its helium-burning days at an end,
白矮星的活动也停止了
the White Dwarf's active life is over.
剩下的只有由碳和氧组成的死去的内核
All it's left with is a dead core of carbon and oxygen.
这已经不算是恒星了 不过是灰烬罢了
It's not really a star at all but a cinder.
而在恒星内部发生的
And the internal battle raging in the heart of the star,
引力与聚变的战斗 现在已见分晓
between gravity and fusion, now has a clear victor.
一旦聚变停止
Once the fusion stops,
恒星在自身引力作用下塌缩
the whole thing collapses under its own weight
形成白矮星
to form a White Dwarf.
成为一颗密度大得难以想象的小型天体
So you've got this very small blob, which is incredibly dense.
将会比它最初时的密度
It's going to be something like a million times denser
高数百万倍
than it started off,
非常非常密
so dense, in fact,
要是有跟我手♥机♥那么大的一块
that if you had a piece the size of my mobile phone,
可能会有差不多十吨♥重
it would weigh something like ten tonnes.
巨大的红巨星 其内核塌缩
The core of the massive Red Giant collapses,
使得白矮星的密度
leaving the White Dwarf denser than anything
比之前发现的任何东西都要高
that had previously been discovered.
这又产生了另一个让人困惑问题
This raises another perplexing question.
为什么引力没能完全毁掉它们呢
Why doesn't gravity completely destroy them?
它们真是谜一样的东西
They were such baffling objects
曾有一名英国天文学家评论道
that one British astronomer commented,
"要是能给白矮星回条信息的话
"An appropriate response to the message from a White Dwarf was
"最合适的一定是 '闭嘴 别瞎说'"
'Shut up, don't talk nonsense.' "
直到物理学有了革命性的重大进步
It took a whole new revolutionary form of physics to emerge
这些谜团才被解开
before their secrets could be unravelled.
量子力学更好地揭示了
Quantum mechanics revealed much more
原子的内部结构
about the innards of atoms,
使得天文学家们
enabling astronomers to
开始破解白矮星的秘密
begin to solve the mystery of the White Dwarf.
在物理学中 我们有两种不同的粒子
In physics, we've got two different types of particles.
有一种是喜欢抱团的粒子
There are some particles that are very gregarious,
喜欢聚在一起
that like to get together,
而另一种粒子
and then we've got other particles,
例如电子
like the electron,
就喜欢彼此分开来
which like to be different from each other.
它们就像在宴会上
They're a little bit like people at a party
撞衫了的人
who are wearing the same colour dress.
它们不喜欢呆在彼此的周围
They don't want to be standing next to each other,
所以它们会自然地拉开彼此间的距离
so they're going to tend to naturally push away from each other.
这就有点像物理学家说的压力
That's...that's like what we physicists call pressure.
这个压力来自于粒子间互相争抢位置
This pressure is created as the particles jostle for position.
这是量子力学的原理
It's a principle of quantum mechanics,
当将其应用到恒星上时
and when it was applied to stars,
死亡白矮星的存在也就说得通了
the lives of dead White Dwarfs suddenly made sense.
阻止它们完全坍缩的原因
What stopped them collapsing completely
就是粒子间产生了压力
was that gravity was resisted by the pressure generated
抵抗了引力的作用
between the particles themselves.
在白矮星中
In a White Dwarf,
引力与压力有着微妙的平衡
you've got a delicate balance between the gravity
引力想要把它压成一团
which is trying to squeeze it together,
而电子不想呆在一块儿
and the pressure of these electrons trying not to
产生了压力
all have their dresses in the same place,
试图往外推
that are trying to push out.
正是二者间的平衡 引力向内拉
And it's the balance between this gravity pulling in
电子向外推
and the electrons pushing out
才使得白矮星成了现在的大小
that keeps the White Dwarf the size it is.
这也让一颗耗尽了燃料的恒星
It's also what lets a star with no fuel supply
继续发光几十亿年
shine for billions of years.
这些白矮星非常小
These White Dwarfs are very small,
所以它们的表面♥积♥也非常小
so they've got a very small surface area,
就是说 虽然它们是白色的 温度高
which means that although they are white hot,
但是它们发出的光和热
the light that they emit, the heat energy which they send out,
依然十分有限
is still very limited just
因为表面♥积♥太小了
because of the very small size of the surface.
如今 它继续发光
Now, it carries on radiating light
并逐渐冷却下来
and it gradually cools down,
变得越来越黯淡
it gradually gets dimmer and dimmer.
有点像
It's a little bit like a
退休的老恒星待在恒星养老院里
retired person sitting in an old stars' home.
它仍然活着
It's still, you know, ticking along,
但渐渐变得
but it gradually gets
越发迟缓 越发黯淡
sort of slower and slower, dimmer and dimmer.
这些白矮星
There are White Dwarfs
遍布我们的银河系 以及其它所有星系
cluttering up our galaxy, all the other galaxies.
白矮星的谜团已被解开
The enigma of the White Dwarf had been resolved.
科学家已经知道绝大多数的恒星
Scientists had discovered how the vast majority of stars,
包括我们的太阳 是如何走向死亡的
including our own Sun, will end their days.
成为白矮星 渐渐消逝在宇宙的黑暗中
As White Dwarfs gently fading into the darkness of the universe.
但并不是所有的恒星都走得无声无息
But not all stars go so quietly.
大多数的大质量恒星 则是轰轰烈烈
For the most massive stars, something extraordinary happens.
它们用最后一次呐喊宣告自己的退场
They make their exit with one last spectacular hurrah.
超新星 是宇宙中大多数大质量恒星
Supernovae are the explosive, dramatic death throes
爆发性的 激动人心的死亡挣扎
of the most massive stars in the universe.
如此明亮和强烈的爆♥炸♥
Explosions so bright and intense
可以与一百亿个太阳发出的光相媲美
that they can briefly rival the output of ten billion Suns.
它们留下的痕迹
They leave behind traces
将天空描绘得五彩斑斓
that paint the sky with a rainbow of colours.
如今我们明白 这些壮丽的场景