宇宙时空之旅（2014）

Cosmos: A SpaceTime Odyssey S01E06

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

在我们的日常生活中
In everyday life on our world,
从原子的尺度上看
on the scale of atoms,
物质从不相互接触
material objects never really touch.
每个原子中心都有个小原子核
Each atom has a tiny nucleus at its center,
由电子云的磁力线包围
surrounded by an electron cloud of lines of force.
当原子相互靠近
As the atoms approach each other,
男孩的电子云排斥女孩的电子云
the boy's electron clouds push away the girl's.
任何原子超过99.9%的质量
More than 99.9% of the matter of any atom
都集中在原子核
is concentrated in its nucleus.
原子核被电子云包围
The nucleus is surrounded by an electron cloud
电子云产生不可见的力场
which produces an invisible field of force,
起到缓冲器的作用
and acts like a shock absorber.
电子云的构型
The configuration of the electron cloud
决定这种元素的性质
determines the nature of an element.
在地球上正常情况下
In the ordinary course of things here on Earth,
原子核不会相互接触
the nuclei never touch.
我们虽然感受到触觉
We have a sensation of touching,
但那不过是隐形力场
but that's really just our invisible force fields
相互重叠排斥的结果
overlapping and repelling each other.
和原子其他部分相比
The nucleus is very small
原子核很小
compared to the rest of the atom.
如果说原子的大小等同于这间教堂
If an atom were the size of this cathedral,
原子核的大小等同于那粒灰尘
its nucleus would be the size of that mote of dust.
原子中绝大部分是真空
An atom is mostly empty space.
要想了解物质的本质
To understand the nature of matter,
我们还需更加深入
we have to go deeper still,
到一个比原子小十万倍的地方
to a place 100,000 times smaller than the atom:
它的原子核
Its nucleus.
宇宙中最简单最多的原子是氢原子
The simplest and most plentiful atom in the cosmos is hydrogen.
它的原子核是单个质子
Its nucleus is a single proton,
也就意味着氢元素是第一号♥元素
which makes hydrogen element number one.
周围的电子云
The clouds that surround it
是氢原子唯一的电子可移♥动♥的区域
are the realms where the atom's lone electron is permitted to roam.
原子核有两个质子会怎样呢
What happens when you have a nucleus with two protons?
质子会相互排斥
Protons repel each other.
要想把它们在原子核里结合到一起
In order to hold them together in a nucleus,
还需要另一种叫中子的粒子
you need other particles called neutrons.
它们负责让质子安守本分
Their job is to keep the protons from getting out of line.
中子用超强核力
They overwhelm the protons
战胜质子斥力让它们吸引在一起
with their strong attractive nuclear force.
原子核有两个质子的元素为二号♥元素
A nucleus with two protons is element number two,
也被称为氦元素
otherwise known as helium.
原子核有六个质子的元素为六号♥元素
A nucleus with six protons is element number six,
也就是碳元素
which is carbon,
构建生命体的基本材料
the fundamental building block of life.
金元素的原子核有79个质子
The nucleus of a gold atom has 79 protons.
它周围的电子云中有79个电子
They attract 79 electrons in clouds around it.
光与这些电子的相互作用
The way light interacts with those electrons
让金闪闪发光
is what makes gold glitter.
原子核中每多一个质子
Every additional proton in the nucleus
就需要足量的中子将它们束缚住
requires enough neutrons to bind them together...
不过有个限度
Up to a point.
原子核中的中子数有上限
There's an upper limit to the number of neutrons you can stuff into
再多就会变得不稳定
a nucleus before it becomes unstable.
我知道有个地方
I know a place
不同原子的原子核真的可以相互接触
where the nuclei of different atoms actually do touch each other.
太阳看起来像个固体天体
The Sun looks like a solid object,
其实不是
but it's not.
它的高温使所有原子处于气态
It's so hot that all its atoms are always in their gaseous state.
地球上使物质呈固态或液态的化学键
The bonds that join atoms to make solids and liquids on Earth
不足以对抗烈日的高温
are not strong enough to withstand the heat of the boiling Sun.
这些比地球还大的炽热弧形气体流
Those arcing streams of incandescent gas that dwarf the Earth
受由太阳内部发射出的
are guided by magnetic lines of force
磁力线操纵
that emanate from below the surface of the Sun.
为什么太阳温度如此高
Why is the Sun so hot?
因为它巨大的引力将原子挤到了一起
Because its own stupendous gravity is squeezing its atoms together.
引力的能量转化为
The energy of gravity is being transformed
运动原子的动能
into the energy of moving atoms.
这就是温度
That's what heat is.
越到太阳的中心
The deeper we go into the Sun,
原子挤得越紧温度越高
the greater the squeezing and the higher the temperature.
在太阳的最中心
In the heart of the Sun,
原子高速运动一旦碰撞就会融合
the atoms are moving so fast that when they collide, they fuse.
原子核会相互接触
Their nuclei touch.
太阳是一个由自身引力维持的
The Sun is a nuclear fusion reactor,
核聚变反应堆
held together by its own gravity.
由向内的引力
It's balanced between the inward pull of gravity
和高温气体向外的推力维持平衡
and the outward push of its hot gases.
这种平衡持续了数十亿年
That balance has lasted billions of years,
它的稳定使地球上生物进化成为可能
providing stability that made possible the evolution of life on Earth.
在太阳的核心
In the Sun's core,
氢原子聚变成氦原子
the fusion of hydrogen into helium
以光子的形式释放核能
releases nuclear energy in the form of photons.
这些光子慢慢到达太阳表面
These particles of light slowly work their way to the surface,
也就成为了日光
where they're seen as sunlight.
氦相当于太阳这个核反应堆的灰烬
Helium is the ash of the Sun's nuclear furnace.
太阳是个中型恒星
The Sun is a medium-sized star.
它的核心也不过是一千万度不算太热
Its core is only a lukewarm ten million degrees...
足以让氢原子聚变
hot enough to fuse hydrogen,
却不足以让氦原子聚变
but too cold to fuse helium.
银河系中有很多恒星可达到更高温度
There are many stars in the galaxy that get much hotter,
因为它们质量更大
because they're more massive
也就有更强的引力
and have more gravity.
这些恒星可让氦原子聚变成更重的原子
Such stars fuse helium into heavier elements,
比如碳原子和氧原子
like carbon and oxygen.
在它们的暮年
In their old age,
它们将这些元素慢慢扩散到太空中
they gently diffuse these elements into space.
还有一些质量更大的恒星
Other stars, more massive yet,
寿命不长
live fast and die young
在灾难性的超新星爆♥炸♥中死亡
in cataclysmic supernova explosions.
在银河系超新星爆♥炸♥大概每世纪发生一次
In our galaxy, such stars go supernova about once a century.
爆♥炸♥时的温度远远超过太阳核心
These explosions are far hotter than the core of the Sun...
足以把像铁这样的元素
hot enough to transform elements like iron
转化成更重的元素释放到太空中
into all the heavier ones and spew them into space.
大麦哲伦星云
The large magellanic cloud
是银河系的相邻星系
is a neighboring galaxy of our milky way.
在南半球的天空中可见
It's visible in the skies of the Southern hemisphere.
当超新星爆♥炸♥时
When a supernova explodes,
它的亮度超越整个星系
its brightness rivals that of its entire galaxy.
但这些光能
But all that light
只占爆♥炸♥释放的总能量的百分之一
is only about one percent of the energy liberated in the explosion.
剩下的能量被宇宙中
The rest of the energy is carried off by the most common
最常见但最神秘的粒子带走
and the most mysterious particles in the cosmos.
此刻有数万亿这种粒子正在穿过你
There are trillions of them passing through you right now,
只需追踪其中的一个
and yet tracking down even one of them
我们就会到达地球上最奇怪的地方
will take us to one of the strangest places on Earth.
追踪中微子是最不寻常的猎捕
Stalking the wild neutrino is the rarest of sport.
要想成功追踪中微子
The lengths one must go to track them down
必须付出超乎寻常的努力
is nothing short of astonishing.
欢迎来到超级神冈探测器
Welcome to Super Kamiokande,
日本地下中微子探测室
the subterranean Japanese neutrino detection chamber.
我们身处地下一公里
We're more than a half mile beneath Earth's surface.
你大概会问哪个脑袋正常的人
You might ask, "Well, who in their right mind
会把天文台埋在地下深处呢
would bury an astronomical observatory so far underground?"
那些要捕捉宇宙中最独特的猎物
Those who hunt the most elusive prey in the cosmos:
即中微子的猎人
The neutrino.
包围着五万顿蒸馏水的
This enormous array of light detectors
光电倍增管阵列
surrounding 50,000 tons of distilled water
是专门捕捉中微子的陷阱
is a trap designed to catch neutrinos only.
其他例子例如宇宙射线
Other particles, such as cosmic rays...