了解宇宙是如何运行的（2010）

How the Universe Works S06E09

Part 6 Dec. 22, 2021, 7:23 p.m.

A single head-on collision would leave traces
留下泰娅和地核的痕迹
of both Thea and Earth's core on the Moon,
但侧击不会产生足够的物质
but a glancing blow wouldn't knock off enough material
来形成像我们这样大的月球
to form a moon as big as ours.
有一种方法可以解决我们今天看到的
One way we can end up with the Earth-moon system
地球-月球系统的所有问题
that we see today and solve all these problems,
那就是不是一次大碰撞
is that instead of having one big collision,
而是一系列的小碰撞
there were a series of several smaller collisions.
每一次撞击都会擦过地壳的一部分
Each impact grazes off a section of Earth's crust
从而在地球周围形成一个环
that forms a ring around our planet.
每一次微小的碰撞
With each small collision,
都会有物质被抛入围绕地球的轨道
material would have been thrown into orbit around the Earth.
最终，这些碰撞碎片合并形成
Eventually this collisional debris merges
一个小的新天体，一个小卫星
to form a small, new moon, a moonlet.
经过几次碰撞后
Now after several of these collisions,
每次碰撞产生的碎片都会围绕地球旋转
you'll have debris from each collision circling the Earth.
其中一些仍然以碎片的形式存在
Some of it is still in the form of debris,
一些以小卫星的形式存在
some of it is in the form of moonlets.
最终它们结合在一起形成了现在的月球
Eventually they coalesce to form our current moon.
看来我们的月球
It seems our moon may well be
很可能是太阳系早期
the product of a series
一系列宇宙碰撞的产物
of cosmic collisions in the early solar system.
我们现在仰望天空时看到的不是卫星
What we see when we look up in the sky now isn't the moon,
但它基本上是最后一个幸存的卫星
but it's basically the last moon that survived.
它只是在所有这些撞击停止时
It was just the one that happened to be there
恰好在那里的一个
when all of these impacts stopped.
我们的月球和太阳系其他成员诞生的过程
The birth of our moon and the rest of our solar system
是暴♥力♥的、混乱的、灾难性的
was violent, chaotic, catastrophic.
当我们观察太阳系的时候当它还很年轻的时候
When we look at the solar system when it was very young,
我们所有的模型几乎都在说同样的事情
all of our models pretty much say the same thing.
这很糟糕，没有秩序
It was not nice and orderly.
这是一场灾难
It was a disaster.
然后事情就安定下来了
And then things settled down.
生命有机会在非常稳定、非常友好的条件下
Life had a chance to take hold and evolve under very stable,
站稳并进化
very friendly conditions.
所以当你现在环顾四周
So when you look around right now,
你看到的是一个古老的，暴♥力♥的过去的故事
you're seeing the story of an ancient, violent past
它逐渐演变成我们今天所知道的
that has smoothed out into the wonderful environment
美好的环境
we know today.
我们的太阳系可能看起来很稳定
Our solar system might seem stable,
但它仍然有一些非常奇怪的地方
but there is still something very strange about it.
仍然有一个持久的谜团
There is still one enduring mystery,
那就是为什么太阳系是倾斜的？
and that is why the solar system tilted?
这八颗行星在
The eight planets orbit
大致相同的平面上运行
in roughly the same flat plane,
但与太阳的自转轴相比
but compared to the spin axis of the Sun,
这个平面是倾斜的，这使得太阳看起来不平衡
that plane is tilted, making the Sun look lopsided.
结果是，当你看太阳的倾斜
And it turns out, when you look at the Sun's tilt,
它实际上倾斜了6度
it's actually tipped by 6 degrees,
这是太阳系的平面
the plane of the solar system.
这听起来可能不是很多
And that may not sound like a lot,
但实际上
but it's actually quite a bit
与太阳系所有行星的倾斜度相比，这是相当斜的
compared to the tilts of all the planets of the solar system,
这个很独特
and this is an outlier.
这很奇怪
It's strange.
是什么造成的呢？
What could have done that?
与我们所知道的太阳系是如何形成的
The tilt contradicts what we know about
相矛盾
how the solar system formed,
一个旋转的云坍缩成一个圆盘
a spinning cloud collapses into a disk.
旋转的圆盘就变成了太阳和所有的行星
The spinning disk then becomes the Sun and all the planets.
它们应该在同一轴上旋转
It should all be spinning on the same axis.
有一种可能的方法可以改变
So one possible way that you could change the orientation
太阳相对于行星所在平面的引力方向
of the pull of the Sun relative to the plane the planets are in,
那就是是否有什么东西
is if there was something out there
在长时间地拉着行星
tugging on the planets for a very long time.
2016年，加州科技天文学家
2016, Cal tech astronomers
康斯坦丁·巴蒂金和迈克·布朗
Konstantin Batygin and Mike Brown
声称他们发现了丢失的东西……
claim they've found the missing something...
第9行星，理论上的一颗巨大的行星
Planet 9, a theoretical giant orbiting off-kilter
在太阳系的偏远地带偏离轨道运行
in the far reaches of the solar system.
第9行星位于一个又长又大的轨道上
Planet 9 resides on a long and substantial orbit,
它本身也相当大，大约是地球的10倍
and it itself is pretty massive, about 10 Earth masses or so.
如果它在一个高度椭圆倾斜的轨道上围绕太阳运行
If it's orbiting the Sun on a highly elliptical tilted orbit,
每次它靠近太阳时
every time it gets close to the Sun,
它就会拉住行星一点
it's going to tug on the planets just a little bit.
但在成千上万次的轨道运行中，它可以颠覆太阳系中
But over hundreds and thousands of orbits, it can actually tip
所有行星的轨道
the orbits of all the planets in the solar system,
但它不会颠覆太阳
but it won't tip the Sun.
在数十亿年的时间里
Over billions of years, the planetary system
恒星系统慢慢扭曲，偏离了原来的平面
slowly twists out of alignment with its original plane.
第9行星的遥远距离
Planet 9's distant reach
可能解决了太阳系倾斜的谜题
may solve the mystery of the solar system's tilt,
但随着太阳开始消亡
but it might also have a disastrous effect
它也可能对外行星产生灾难性的影响
on the outer planets as the Sun starts to die.
太阳就像宇宙中的其他恒星一样
the Sun, just like every other star in the universe,
也有生命周期
has a life cycle.
它诞生了
It was born.
它现在正过着它的生活，它也将会死去
It is currently living its life, and it will die.
当它死亡时，它会膨胀成一颗红巨星
As it dies, it will bloat up into a red giant star,
然后外层开始漂移
and then the outer layers will begin to drift away.
这就意味着太阳的质量
Now what that means is that
会迅速下降
the Sun will be losing mass very quickly.
让我们围绕太阳运行的
The thing that holds us in orbit around the Sun
是太阳的引力
is the gravitational pull of the Sun.
那么这对行星意味着什么呢？
所以，太阳不会轻轻地进入那个美好的夜晚
它肯定会吞没水星
它还将扩张并吞噬地球、金星
也许我们并不确定
但不管怎样，我们都会被煮熟，所有的内行星都会被煮熟
但是外行星呢？
随着太阳外层的膨胀
Jupiter, Saturn, Uranus, and Neptune
木星、土星、天王星
will move away from the Sun
和海王星将远离太阳
as its outer layers expand,
但遥远的第九颗行星并非如此
but that's not the case for distant Planet 9.
科学家们认为，第9行星的轨道
Scientists think that Planet 9 orbits
离太阳太远，当太阳消亡时
so far out that as the Sun dies,
它对行星的引力将会减弱
it will loosen its gravitational grip on the planet.
第9行星开始会感受到其他天体比太阳
Planet 9 starts to feel the influence of other objects
更大的影响
more than the Sun.
例如，一颗路过的恒星
It turns out a passing star, for example,
可能会影响它的轨道
could affect its orbit,
甚至是星系本身的潮汐也会
or even tides from the galaxy itself,
我们的星系的重力场会影响这颗行星
our galaxy's gravitational field can affect this planet,
并把它丢进太阳系内部
and drop it into the inner solar system.
第9行星轨道的变化
This change in Planet 9's orbits
对太阳系来说可能是灾难性的
could be disastrous for the solar system.
如果发生这种情况
And if that happens,
它可能会对木星、土星、天王星和海王星
it could actually wreak havoc on the gas giants
等气态巨行星造成严重破坏
Jupiter, Saturn, Uranus, and Neptune
扭曲它们的轨道
and distort their orbits,
可能会把它们抛向太阳
maybe dropping them into the Sun
或者把它们抛出太阳系
or flinging them out of the solar system, as well.
第9行星可能会使太阳系的灭亡
Planet 9 could make the death of the solar system
如同它的诞生一样剧烈
just as violent as its birth.
现在我们正处在这个美妙的最佳位置
Right now we're in this wonderful sweet spot
在这里生命可以进化并在两个
where life can evolve and take hold between
几乎难以想象的暴♥力♥时代之间站稳
two eras of almost unimaginable violence.
如果真的有第九颗行星，那就有点像
If there is a Planet 9, then it's kind of a rehash
早期太阳系发生的事情的翻版
of what happened in the early solar system,
当时因为一颗巨大的行星向内移♥动♥
when everything was really chaotic
一切都非常混乱
because of a giant planet moving inward.
同样的事情可能再次发生
The same thing could happen again.
出生在混乱
Born in chaos.