了解宇宙是如何运行的（2010）

How the Universe Works S05E09

Part 2 April 18, 2021, 7:48 p.m.

Our solar system only has one star.
大多数恒星系不止一个恒星
Most solar systems have more than one.
恒星围绕彼此旋转
And the stars orbit around each other.
数十亿年前
Billions of years ago,
这颗钻石行星是一颗黄色的恒星
the diamond planet is a yellow star,
很像我们的太阳
much like our sun.
它的大得多的双星伙伴
Its much larger binary partner quickly
迅速燃烧完了它的燃料
burns through its fuel supply
然后爆♥炸♥成一颗猛烈的超新星
and then explodes in a violent supernova,
留下了一颗脉冲星的残骸
leaving behind a remnant, a pulsar.
这颗类似太阳的恒星足够大
The sun-like star is big enough to survive the blast.
可以在爆♥炸♥中幸存下来
But billions of years later,
它也会耗尽燃料并死亡
it too runs out of fuel and dies,
留下一个被称为白矮星的燃尽的核心
leaving behind a burnt-out core known as a white dwarf.
脉冲星的引力
The gravity of the pulsar starts
开始从白矮星的外层
to steal the lighter elements,
窃取氢和氦等
hydrogen and helium,
较轻的元素
from the outer layers of the white dwarf
直到几乎只剩下
until pretty much all that's left are
这颗死亡的恒星在其生命周期中
the molecules of carbon
所产生的所有碳分子
the dead star produced during its lifetime.
剩余物中的压力非常大
The pressures in the leftover ball
以至于碳只能以结晶的形式存在
are so intense that the carbon crystallizes,
最终变成了一颗压实的钻石星球
turning it into a compacted diamond.
不过，实证明这些宇宙钻石并不是永恒的
But it turns out these cosmic diamonds aren't forever.
脉冲星的引力吸引着这颗钻石行星
The gravity of the pulsar pulls on the diamond planet,
让它沿着缓慢而不断减少的死亡螺旋
hauling inwards on a slow
慢慢向脉冲星靠近
and ever-decreasing death spiral.
在某个时刻，当它越来越接近那个脉冲星时
At some point, as it gets closer and closer to that pulsar,
引力越来越难将它拉伸
it's feeling a harder and harder gravitational stretching.
当它离脉冲星很近的时候，这种力量会变得非常强大
When it gets very close, that force will get so strong,
会把整个星球撕成碎片
it will rip that planet apart.
想象一下
Imagine the view
一颗一万亿克拉的钻石
as a 10-thousand-billion- billion-billion-karat diamond
被撕成碎片
is ripped to pieces.
自身的引力再也不能把身体聚集在一起
Gravity cannot hold the body together anymore.
而且。。。它基本上被撕碎了
And it ... it basically gets torn apart.
现在，你所拥有的只是。。。一场钻石雨
And now, what you have is a ... a shower of diamonds.
我是说，这听起来很神奇
I mean, that sounds amazing.
从死亡恒星的核心中
Extreme diamond planets forged
锻造出来的极端钻石行星
from the hearts of dead stars
点燃了人们的想象力
fire the imagination.
但是系外行星猎人
But what exoplanet hunters
真正想找到的是类似我们地球这样的行星
really want to find are worlds like our own.
一般来说，天文学家寻找系外行星
Astronomers, in general, are looking for exoplanets
是因为它们很酷
because they're cool.
但拜托我们是人类
But come on. We're human beings.
我们想找到另一个像地球一样的行星
And we want to find another planet like earth.
而在2016年，天文学家们发现
And in 2016, astronomers are shocked
一颗潜在的类地行星
when they discover a potentially earth-like planet
围绕着我们最近的比邻星运行时感到震惊
orbiting our closest neighboring star.
震惊的科学家们想知道
Stunned scientists wonder,
这个新的系外行星
will this new exoplanet
会有它所需要的东西来孕育生命
have what it takes to give birth to life,
智慧生命
intelligent life,
甚至文明吗？
even civilizations?
看看夜空
Take a look at the night sky.
我们现在知道行星可能围绕着
We now know that planets probably surround
你所看到的几乎每一个光点
almost every point of light you see.
但还有更多
But there's more.
我们每看到一颗星星
For every star we can see,
都有另外无数颗
there are countless others too dim
我们无法看到的恒星
for our eyes to pick out.
这些是红矮星
These are the red dwarfs,
比太阳小得多
far smaller than the sun
但它们却是行星的家园
but home to planets by the truckload.
许多这样的星球
And many of these worlds
是和地球一样由岩石构成的
are made from rock like the earth.
红矮星比银河系中
There are more red dwarfs
任何一种恒星都多
than any other kind of star in the galaxy.
这些恒星也有行星的
And these stars have planets, too.
所以我们银河系中最常见的行星
So the most common type of planet in our galaxy
是一颗生活在红矮星周围的行星
is one that lives around a red dwarf.
在银河系数十亿颗红矮星中
Of the billions of red dwarfs in the milky way,
超过二十分之一的行星的轨道
more than one in 20 have planets
距离刚好
that orbit at just the right distance
适合液态水在表面聚集
for liquid water to collect on the surface.
如果再靠近一点
Any closer, the temperature would be too hot,
温度就会太热，地表水就会沸腾
and the surface water would boil.
而再远一点，水就会结冰
Any farther away and the water would freeze.
它常被称为“宜居带”
It's often called the goldilocks zone
因为它正好适合海洋的形成
because it's just right for oceans to form,
就像在地球上一样
just as they did on the earth.
这些温暖潮湿的世界
Could one of these warm,
能为我们这样的生命提供栖息地吗
wet worlds provide a habitat for life like us?
这是整件事的圣杯
That's kinda the holy grail of this whole thing,
找到一个像家一样的地方
to find something that looks like home.
首先，这意味着它可能有生命
For one thing, that means that it could have life on it.
它可能适合居住
It could be habitable.
这是我们一直想要的解决的问题
And that's something that we've always wanted
我们在宇宙中孤独吗？
are we alone?
这些潮湿的岩石行星
These rocky, wet planets
看起来像是地球的替身
may seem like dead ringers for the earth.
但这里有个问题
But there's a catch.
许多红矮星的行星的运行轨道
Many red-dwarf worlds
离它们的暗淡的恒星非常近
orbit so closely to their demo stars
导致行星的同一面
that the same side of the planet
总是朝向恒星
would always face inwards,
永远被恒星的巨大引力锁定
held in place forever by the star's immense gravity.
科学家称这种现象为潮汐锁定
Scientists call this phenomenon tidal locking.
我们都很熟悉这样一个事实
We're all familiar with the fact that the earth spins on its axis
地球绕着它的轴旋转
and gives us night and day.
给了我们黑夜和白天
But if you move in closer to a star, eventually,
但引力的相互作用会阻止这种旋转
the gravitational interaction will stop that rotation.
致使星球的一面将永远面对恒星
One side of the planet will always face the star.
另一边总是面朝别处
One side will always face away.
所以，它被潮汐锁住了
And you're tidally locked.
如果你降落在这个星球上
If you land on this planet and look around,
环顾四周，你会看到不同的景色
you're gonna see stuff that's very different depending on
这取决于你在哪里
where you are.
如果你在行星的某一点，就在恒星下面
If you're on the point on the planet
所以当你抬头看天上的
that is underneath the star
恒星一直在正上方
so that, when you look up, that star is straight up,
它永远停留在那个地方
that's where it's always gonna be.
它永远不升起也永远不会降落
It never rises. It never sets.
一直不会移♥动♥
It never moves.
恒星就在一直在那里
That's where the star is.
但是，如果你在星球的另一边
Now, if you're on the other side of the planet,
将总是在晚上，你抬头看
it's always nighttime ... you look up,
你永远看不到天上的主星
you never see your host star in the sky.
2016年
In 2016, astronomers discovered
天文学家发现了一颗潜在的类地行星
a potentially earth-like planet
围绕着离太阳最近的
orbiting the sun's closest neighboring star,
比邻星半人马座（proxima centauri）运行
proxima centauri.
这颗被称为proxima b的行星
The planet, dubbed proxima b,
离它的宿主很近
sits close enough to its host
可以拥有像地球一样的海洋
to have oceans like the earth.
但科学家怀疑它被潮汐锁住了
But scientists suspect its tidally locked.
结果：Proxima b可能看上去
The result: Proxima b may be staring at its parent star
像一个巨大的眼球一样盯着它的母星
like a giant eyeball.
夜晚是一片黑暗、冰冻的荒野