了解宇宙是如何运行的（2010）

How the Universe Works S01E05

Part 2 April 18, 2021, 7:56 p.m.

And in fact, Type la supernovae
are of vital importance
它们令宇宙布满…
to populating the universe
with the kind of elements
对我们至关重要的元素
that are important to us.
la型超新星将铁喷射到数万亿哩外
Type la supernovas blast iron
trillions of miles into space.
宇宙中大部分铁来自超新星
It's where most of the iron
in the cosmos comes from.
但比铁重的元素, 如金和银呢?
But what about all the elements that are
heavier than iron, like gold and silver?
它们又来自哪里呢?
Where do they come from?
答案是其它恒星
The answer again is other stars.
单星, 更大的恒星
Single stars. Bigger stars.
超新星创造了宇宙万物
Supernovas make
everything in the universe.
地球上所有物质
Everything we see, all the
material in planet Earth,
都是在超新星内部创造的
was created inside a supernova.
连你和我也同样源自垂死的恒星
Even you and I are
made from dying stars.
没有超新星, 我们不会存在
Without supernovae, we wouldn't be here.
身体中每个原子都来自爆♥炸♥的恒星
Every atom in your body was
once inside a star that exploded.
也许我们左手的原子与右手的原子
And the atoms in your left hand
来自两个不同的恒星
may have come from a different star
than the atoms in your right hand.
你其实是星尘
You are literally stardust.
太阳系中几乎所有的铁来自…
Almost all of the iron in our solar
system came from a double star supernova
一个50多亿年前爆♥炸♥的双子超新星
that exploded more than
five billion years ago.
从地球的内核到摩天大楼
From our planet's molten core
- to our skyscrapers...
再到血液中的血红蛋白
to the haemoglobin in our blood.
都是由来自la型超新星的铁构成的
it's all made of iron
from Type la supernovas.
但较重的元素, 像金, 银和铀
But the heavier elements in our
world, like gold, silver and uranium,
则来自另一种超新星
come from another type of supernova...
单星超新星
a single star supernova.
这是太阳
This is our sun.
重量远大于太阳的单星
A single star has to weigh
much more than oir sun
才可能成为超新星
to go supernova.
这些巨星确实存在
And there are sane
monster stars out there.
有些比太阳重数十倍
Some are dozens of times
heavier than our sun.
有些重数百倍
And some are hundreds
of times more massive.
越重的恒星, 燃烧得越快
The heavier the star,
the faster it burns.
一旦这些庞然大物开始衰老和死亡
And when these massive
stars begin to age and die,
内部的核反应便会加速
the nuclear reactions
inside them speed up.
巨星消耗核燃料非常迅速
Giant stars bun through their
nuclear fuel very, very fast
这有点像放纵生活, 英年早逝
It's sort of the, you know,
the live fast, die young.
恒星的质量越大
The more mass a star has,
内部燃烧的温度越高
the hotter it burns inside,
燃料消耗得也就越快
the faster it burns through its fuel.
与双子超新星不同的是
Unlike double star supernovas,
巨型单星在爆♥炸♥前创造了大量元素
really massive single stars create
lots of elements before they explode.
一旦将氢转化成氦
Once they turn hydrogen into helium,
氦转化成碳, 和碳转化成氧
helium into carbon,
and carbon into oxygen,
它们不会塌缩成白矮星
they don't collapse
into white dwarf stars.
相反这颗巨星会继续燃烧
Instead, giant stars keep on burning...
在内核深处形成一层层新元素
building up layer after layer of
new elements deep in their core.
巨星将氦转成碳和氧后不会停下来
Big stars don't stop after they've
burned helium to carbon and oxygen.
它们继续燃烧, 将碳烧成更重元素
They go ahead and burn carbon
to still heavier elements
然后将氖和氧转化成硅
and then neon and oxygen to silicon...
直到形成一个像俄♥罗♥斯♥套娃一样的
until you get this
nested Russian doll...
球形千层糕
spherical layer cake kind of thing.
这些元素是构成宇宙的基础材料
These elements are the bui I
ding blocks of the universe...
但它们被困在巨星内部
but they're trapped
inside the giant star.
它们总会出来的
Somehow they've got to get out.
通过研究爆♥炸♥的恒星
Studying exploding stars has taught us
我们发现重元素是如何形成的
how the heavy elements of
the universe came to be.
它们形成于巨星内部的核反应
They were formed... by
nuclear reactions inside stars.
但若有些巨星没有爆♥炸♥
But if some of those
stars were not to explode,
那么这些元素将永远封存
then those elements would
be locked up forever.
引发巨大单星释放元素的原因
The trigger that will release the
elements in the single giant star
正是同样引发la型超新星爆♥炸♥的
is the same element that causes
the Type la supernova to blow up...
铁元素
iron.
铁耗尽恒星核聚变产生的所有能量
Iron eats up all the energy
of the star's nuclear fusion.
没有了核聚变能量向外扩张的压力
Without the energy from
nuclear fusion pushing out,
引力开始向内挤压
gravity begins to crush down.
巨星注定要毁灭
The big star is doomed.
恒星的最后时刻非常壮观
The last moments of a
star are really phenomenal.
恒星也许经历了 1000万年
The star might last for 10 million years
才成为超新星
on the way to becoming a supernova,
但最后一刻来得非常迅速
but the last little bit
takes place very rapidly.
一旦具备铁质内核和一旦失去平衡
Once you have an iron core and
once it gets out of balance,
它就会在一毫秒内塌缩
it col lapses in a thousandth
of a second, a millisecond,
就如同从地球变成曼哈顿那么小
from the size of the Earth
down to the size of Manhattan.
塌缩时以三分之一光速的速度移♥动♥
It's travelling about one-third of
the speed of light as it crunches down.
当恒星变得不稳定时
As the star becomes unstable,
巨大引力引起内核塌缩
the massive power of gravity
causes the core to collapse.
这过程释放出巨大能量
This happens with such incredible power,
致使内部原子也开始挤压在一起
even the atoms inside
start to crush together.
当恒星逐渐变小和密度变大
As it gets smaller and denser,
内核开始累积越来越多能量
the core builds up more and more energy.
它的质量是太阳的1.5倍
It's something with about one and
a half times the mass of the sun
而塌缩后的直径只有15哩
that has collapsed to something
that's only about 15 miles across.
密度的确大得惊人
It's got incredible density.
是水的密度的一千万亿倍
You know, it's a thousand trillion
times the density of water.
现在这颗恒星爆♥炸♥了
Now, the star explodes.
爆♥炸♥穿透恒星外层
The blast rips through
the star's outer layers,
在过程中创造出所有比铁重的元素
and in the process, makes all
the elements heavier than iron.
铁变成钴
Iron becomes cobalt
钴变成镍
Cobalt becomes nickel.
然后变成金, 铂和铀
And on and on to gold,
platinum and uranium.
爆♥炸♥很短暂
The explosion is so brief
只制♥造♥了少量重元素
it only makes small amounts
of these heavier elements,
这也是它们这样稀少的原因
which is why they're so rare.
超新星把这些新元素
The supernova blasts these new elements
喷射到数十亿哩外的太空中
billions of miles into space.
我们知道的唯一方法
The only method we know,
宇宙里能够创造新元素的…
the only mechanism that we have
found anywhere in the universe
唯一途径
for creating new elements...
就是在作垂死挣扎的恒星
is in the death throes of a star.,.
叫做超新星
called a supernova.
令人难以置信的是会有物质…
It seems incredible that anything