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原子来自哪里?来自许多亿年前的宇宙烟火

Where do atoms come from? Billions of years of cosmic fireworks. | Michelle Thaller

向天文学家提问吧
Don:嗨 米歇尔博士 宇宙初开就产生了元素周期表吗?
Don, you have asked a question that’s related to
Don 你问的这个问题
what I think is my absolute favorite fact in the universe
和我自认为最喜欢的宇宙事实具有一定的相关性
and that is that we are made of dead stars
那就是 我们是由死恒星组成的
And that’s literally true.
这是千真万确的
The atoms in our bodies were actually created inside the cause of stars
我们体内的原子实际上是在恒星内部产生的
that then it exploded and died, or unraveled into space.
然后恒星爆炸 死亡 或者解体进入太空
And so your question about the periodic table is very interesting.
所以你提出的关于元素周期表的问题非常有趣
Well, what’s the periodic table like
那宇宙初开 也就是宇宙大爆炸的那一刻
at the beginning of the universe the moment of Big Bang?
元素周期表是什么样的呢?
Well one thing I can say, it was a lot simpler.
我可以说 它要简单得多
Eh, The Big Bang, when it went off, produced basically three elements.
宇宙大爆炸发生的时候 总的来说就产生了三种元素
Almost everything was hydrogen.
主要是氢
There was a little bit of helium,
少量的氦
and a tiny tiny little smattering of lithium as well.
还有极少量的锂
So those three elements were around
所以 这三种元素
just a couple of minutes after the formation of the universe
是在宇宙形成后几分钟就产生了
but nothing else.
但除此之外 别无他物
And, and that’s actually not a theory.
而且 这并不是一个理论
That’s actually something we can observe.
而是我们可以真真切切观察到的
One of the wonderful things about being an astronomer is,
成为天文学家的其中一个美妙之处就在于
as you look out into space farther and farther away
当你观望的宇宙空间越来越遥远
the light has taken longer to get to you.
光来到你身边的旅途就越来越漫长
And the farthest we can see is actually back to a time
目之所及 最遥远的实际上就要回到
only about 400,000 years after the Big Bang.
宇宙大爆炸后的40万年左右
And really, at that time,
说真的 那个时候
there was nothing but very hot hydrogen gas,
宇宙除了滚烫的氢气 还有一点点的氦和锂
and a little bit of helium and lithium as well.
其它什么都没有
So everything larger than that,
所以 所有比这些更大
every atom more complex,
更复杂的原子
had to be formed inside a star.
都必须要在恒星内部形成
Over time, our stars, like the sun,
随着时间的推移 恒星 比如说太阳
are pretty good over the life circle of producing things like carbon and oxygen.
在生命演化过程中很容易产生碳氧之类的物质
They don’t really get much more far off the periodic table than that.
它们在元素周期表中确实没有处于太靠后的位置
If you want to go any farther than the element iron,
如果你想得到铁之后的元素
you actually need a very violent explosion,
那就需要非常剧烈的爆炸
a supernova explosion
超新星爆炸
The cores of very massive stars —
大质量恒星的核心
by that I mean stars that are
大质量的意思是说 这些恒星的质量
10, 20 maybe as much as 50 times the mass of the sun,
是太阳质量的10倍 20倍亦或50倍
their cores are much hotter,
而它们的核心温度更高
because the gravity crushes things down,
因为引力的坍缩作用
and temperature goes up many many millions of degrees hotter than inside the sun.
它们的核心温度要高于太阳内部温度几百万度
So these stars can actually form bigger and bigger atoms.
所以 事实上它们是能够形成越来越大的原子
The hotter the temperature, the denser the core,
温度越高 核密度越大
the more you can ram things together
就有越多的物质发生撞击
and actually form bigger and bigger atoms over time.
随着时间的推移 就会形成越来越大的原子
But there’s a very special thing that happens
但是 当铁原子形成时
when you get to the atom iron.
就会些有特殊的事情发生
And it’s something you’ve actually heard about but you may never have thought of.
这些事你已经听说 但可能从未想过
And that when people think about getting energy out of a nuclear reaction
而当人类想从核反应中获取能量时
you’ve heard about fusion reactions.
你们听说过核聚变反应
So like a fusion bomb,
像氢弹一样
actually takes hydrogen, fuses it together to make helium,
将氢聚变生成氦
and that creates energy.
并释放大量能量
And that’s a nuclear bomb.
这就是核弹
The sun also runs on that particular reaction,
太阳也发生着氢聚变
fusing hydrogen together.
这种特殊的反应
But then you also heard that there’s something called fission.
但你们可能也听说过 还有一些所谓的核裂变
And this is how, say, a uranium bomb would work.
这就涉及到铀弹的工作原理
A uranium nucleus has many, many particles inside it
铀核内有很多很多的粒子
you actually get energy out of breaking it up,
要获取能量 就要裂变铀核
and forming two smaller nuclei
形成两个更小的核
that are actually a bit denser and they hold together better.
这两个核的密度更大一点 也更容易结合
And so you get energy out of breaking them apart.
那么就可以通过分裂它们来获取能量
And the element iron is exactly halfway between those two processes.
而铁元素刚好处于这两个过程的中间环节
So you’ve been getting energy by fusing things together until you get to iron.
所以在聚变反应到达铁之前 你都可以通过聚变来获取能量
And iron is the first nucleus
而铁是第一个
where you don’t get any energy out of fusing it.
不能从聚变中获取能量的原子核
From anything bigger now,
目前从任何更大的原子那里
you get energy out of ripping apart fission.
你都可以通过裂变获取能量
So iron is what sets off a supernova explosion.
因此 铁就是引发超新星爆炸的物质
When a star tries to fuse iron together, it absorbs energy.
当恒星要聚合铁 就要吸收能量
And that’s not great for the star.
而恒星能量供给不足
The core collapses.
其核心就会坍塌
And that huge collapse creates this giant wave of heat
而且这种巨大的坍塌会产生巨大的热浪
and the formation of many, many new elements after that.
之后会形成许许多多的新元素
So anything heavier than iron has to be created in a supernova explosion.
因此 所有比铁重的元素都是在超新星爆炸中产生的
Now there are some elements heavier still
目前 还有一些更重的元素
that even supernova energies don’t really
即使是超新星的能量
get up to quite high enough to make.
都无法达到那么高 使其形成
And this is something we only found out
这是最近几年
recently in the last couple of years.
我们才发现的
Elements like gold.
比如说 金元素
Gold is actually a really interesting one.
金是一种很有趣的元素
Platinum are interesting enough.
铂也很有趣
Bismuth, and all the big things like uraniumand, all of the really large atoms,
铋和所有铀之类的大元素 所有的大原子
they have to be formed by something that seems almost preposterous,
它们必须是由某种看似荒谬的东西形成
but we have observed this happening
而我们观测到这发生于
two neutron stars colliding
两颗中子星相撞
So neutron stars are the cores of dead stars.
所以中子星是死恒星的核心
They’re super-compressed.
它们超压缩
The density of a neutron star
至于中子星的密度
is about a Mount Everest worth of mass in every square centimeter.
它每平方厘米的质量就相当于一座珠穆朗玛峰
So think about crushing Mount Everest into a little cube like that.
来想象一下 把珠穆朗玛峰压成这么小的一个立方体
The entire star, which is only about 10 miles across,
而整个恒星的直径又只有10英里左右
is actually that density.
事实上 中子星的密度就是这样
And that means you have a tremendous amount of nuclear components —
这也就意味着有大量的核成分
neutrons, protons really close together.
中子 质子非常靠近
And two neutron stars collide, and when that happens,
当两个中子星相撞之时
you make all of these very heavy elements up like gold,
所有这些超重元素就被组建起来了
and platinum, and uranium, and all the big stuff.
比如金 铂 铀以及所有大元素
And again, this is not something that we just know theoretically.
再次强调 这些并不仅仅只是我们所了解的理论
We actually have observed this happening.
而是我们确实见证过这种情况
Recently, we observed two neutron stars colliding.
最近 我们观测到两颗中子星相撞
And in that single explosion,
而且在那一次爆炸中
10,000 times the mass of the Earth in gold came out of that explosion.
释放出了10000倍地球质量的金元素
It was tremendous .
太惊人了
So we definitely know where those atoms come from now,
所以 现在我们清楚地知道原子从何而来
we observed that happening.
我们也见证过
So to recap,
那么 来回顾一下
at the beginning of the universe, you had three elements,
宇宙初开 就存在着三种元素
mostly hydrogen, a little bit of helium, tiny little bit of lithium.
主要是氢 还有少量的氦和极少量的锂
Now we have the entire periodic table.
现在我们有了整个元素周期表
And a lot of those are formed in stars like the sun.
其中很多都是在像太阳之类的恒星中形成的
Anything past iron has to be
铁之后的元素都必须
formed much more violently in a supernova explosion
在更激烈的超新星爆炸中形成
or in the case of very large atoms,
或是在两个原子都非常大的情况下
two colliding neutron stars.
由两颗中子星相撞形成
And over billions of years, we’ve filled out the periodic table that way.
数十亿年来 我们就是这样填写元素周期表的

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视频概述

简单介绍了元素周期表的发展过程,首先产生的原子是什么,以及这些原子通过什么方式形成越来越复杂的原子,最终形成我们今天所熟知的元素周期表

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收集自网络

翻译译者

长安小盆友

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审核员Y

视频来源

https://www.youtube.com/watch?v=-WZ8D6MWUL4

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