了解宇宙是如何运行的（2010）

How the Universe Works S06E02

Part 4 Dec. 22, 2021, 7:22 p.m.

八大行星和其他许多，许多的小天体
why its where it is based on, you know,
我们都能解释为什么它在那里诞生或运行
the eight planets and many, many other small bodies.
塞德娜不能用那些天体的理论来解释
Sedna cannot be explained by that,
而且，你知道，这标志着塞德娜非常神秘
and, you know, that's the sign of a good mystery.
一定是发生了什么事情
Something else must have happened.
当用计算机来模拟改变天体运行的轨道时
Looking at models for how you can change
塞德纳几乎不可能
the orbits of objects, there's almost no way
在我们的太阳系中形成
Sedna could've formed in our solar system,
然后改变轨道，使它变成椭圆形
and then had its orbit change so that it's that elliptical
并飞到离太阳那么远的地方
and goes that far out from the Sun.
这意味着也许，我是说也许，它不是在太阳系形成的
And that means maybe... Maybe... it didn't form here.
可能是来自一个陌生的世界
It may be an alien world.
我们的太阳系是如何捕获
How could our solar system
一个来自外星世界的天体的呢？
have snagged an alien world?
很久以前，我们的太阳
Long ago, it turns out our sun
可能与其他恒星摩擦过宇宙的肩膀
may have rubbed cosmic shoulders with other stars.
太阳出生在一个恒星的托儿所
It was born in a stellar nursery...
接近过许多其他婴儿恒星
Close to many other embryonic stars.
所以，如果太阳出生在一个非常密集的区域
So if the Sun was born in a very dense neighborhood,
许多其他恒星同时在这一区域诞生
whereby a lot of other stars
那么在这些恒星形成行星时
were forming at the same time in the same region,
它们之间的进行物质交换
it is absolutely possible that material could be exchanged
是绝对有可能的
between these stars as they're forming planets.
塞德娜可能和其他恒星周围的天体一样
Sedna may have formed just like any other object
在一个漂亮的圆形轨道上形成
around another star... In a nice, circular orbit
我们的太阳经过了那个外星太阳系的主要行星
out past the main planets of that alien solar system,
如果那颗恒星离太阳足够近
but if that star got close enough to the Sun,
我们的引力可能会把塞德娜给偷出来
our gravity may have been able to lift Sedna out and steal it.
很有可能其他矮行星
It's possible that other dwarf planets
也是从其他星系中被绑♥架♥而来
were abducted from other systems
这些外来星携带有外星世界的水
and that these alien worlds carried alien water
甚至是外星的有机物质并带到内行星上
and even alien organic materials to the inner planets.
或许还有另外一种解释
这个奇怪的轨道或许是因为
在我们的太阳系中还隐藏着难以捉摸的九号♥行星
这个遥远的隐藏行星被认为是非常巨大
它的引力可以使得塞德娜的轨道形成椭圆形
塞德娜可能是第一个揭示九号♥行星存在的天体
我们可以用是九大行星的原型来追踪这颗行星
对其他遥远物体的跟踪
发现了一组有着同样奇怪的椭圆轨道的物体
在太阳系外♥围♥有一组天体
它们的轨道基本上是相互对齐的
我们本以为这些轨道会是这样、这样、这样或那样
但事实并非如此。他们有着相似的步伐
它们都在朝一个方向旋转
但是不太确定，因为距离实在太远了
所以不太可能得到精确的数据
或许只是偶然
或许它们的轨道就是这样排列的
如果在太阳系中有这么一颗巨大的行星，九号♥行星
我们将继续研究追踪
我们还没有找到第九行星
在我们找到之前
我们会从侧面了解它，我们完全可以做得到
但这颗行星正迫使我们重新评估我们自己的宇宙邻居
这种想法很诱人，这让我们更进一步
It's so tempting to think that we understand something
理解了我们的太阳系，我们的家
as basic as our own solar system, our own home.
当你发现像塞德娜这样的天体时
When you discover something like Sedna,
你会意识到可能还有很多我们没有发现的东西
you realize there could be a lot out there that we haven't seen.
我们的太阳系可能
There are objects that are small like Sedna
还有许多像塞德娜一样的小天体
that are just so far away
它们离我们很远，我们无法探测到它们
that they're beyond our limit to detect them,
所以可能还有成百上千的这样的天体
so there could be hundreds, thousands, tens of thousands
这些太阳系中新的组成部分
of objects out there, new parts of our solar system
还在等待着我们去发现
that are still waiting to be discovered.
而这些遍布太阳系的矮行星
Dwarf planets all over the solar system
正在揭示隐藏的生命
are revealing hidden lives.
在小行星带，谷神星表面的盐
In the asteroid belt, salt on the surface of Ceres
表明在地表下有液态水
suggests liquid water beneath the surface.
Farther out, the new horizons mission
在更远的地方，“新地平线”探测器
found subsurface oceans on Pluto.
在冥王星上发现了地下海洋
我们过去一直认为
We used to think that water could only exist
水只可能存在于宜居带
in this Goldilocks zone,
这里即不会很热，不会导致水的沸腾
where it's not so hot that the water boils off
也不是那么冷，水不会结冰成固体
and it's not so cold that it freezes,
但现在这个观点显然已经Out了
but that's not the case anymore.
我们环顾四周，发现周围到处都有水
We look around, and we find water
我们在太阳系最意想不到的地方发现了水
in the most unexpected places in our own solar system.
这是现代行星科学的
This is kind of a revelation
最新发现
of modern planetary science
即太阳系外♥围♥的许多行星上
that so many of these worlds in the outer solar system
可能存在有地下液态水海洋
may have subsurface oceans of liquid water.
看到我们在研究这些世界的内部结构上
It kind of boggles the mind to see how far we've come
已经取得了这么大的进步
in our understanding
这有点让人吃惊
of the interior structures of these worlds.
在离太阳这么远的地方
Finding liquid water so far from the Sun
发现液态水让科学家们震惊……
left scientists stunned...
……而当我们近距离研究
...and the surprises keep on coming
这些遥远的世界时，更有不断的惊喜出现
as we study these distant worlds up close.
鸟神星，2/3冥王星大小
Makemake, 2/3 the size of Pluto.
表面覆盖着乙烷和甲烷冰
Its surface is covered in ethane and methane ice.
甲烷被冻结成1/2英寸大小的冰粒
The methane is frozen into 1/2-inch-sized ice grains.
它与阳光发生反应，形成一种叫做索林（tholins）的有机物分子
It reacts with sunlight, forming organic molecules call tholins.
这些颜色让这个星球呈现出红棕色
These color the planet red-brown.
更远的地方是阋神星
Farther out lies Eris.
它距离太阳90亿英里（约145亿公里）
It's 9 billion miles from the Sun,
它的表面温度
and its surface temperature...
大约零下400华氏度（-240℃）
About 400 degrees Fahrenheit below zero.
阋神星绝对是一个诱人的天体
Eris is an absolutely tantalizing object.
我们对它所知甚少
We really don't know much about it at all.
它应该与冥王星非常相似
It should be very similar to Pluto,
但我们注意到的一件事是
but one of the things we notice
冥王星的表面有点不完整
is that Pluto's surface is kind of patchy.
有非常明亮的区域
There are areas that are very bright,
也有非常暗的区域
but also areas that are quite dark.
而阋神星表面看起来几乎完全是明亮的
Eris, on the other hand, seems to be almost entirely bright.
阋神星是太阳系中
Eris is one of the shiniest objects
最耀眼的天体之一
in the solar system,
它会反射96%的光线
reflecting 96% of the light that hits it.
科学家想知道为什么会这样
Scientists wondered why.
一个证据来自它的近邻冥王星
A clue comes from its near neighbor, Pluto.
当新视野飞过时，它发现了一些奇怪的东西
When new horizons flew past, it spotted something strange.
其中一个有趣的小细节是
One of the funny little details is that as we flew over Pluto,
当我们飞过冥王星时
we realized that there were things
我们意识到下面有些东西看起来很像沙丘
that looked a lot like sand dunes down there.
这听起来可能不是那么的异国情调
Now, that may not sound incredibly exotic.
你知道，沙丘有什么有趣的地方吗？
You know, what's very interesting about a sand dune?
沙丘听起来可能很沉闷
Sand dunes may sound dull,
但它们能揭示很多行星活动的机制
but they can reveal a lot about the mechanics of a planet.
冥王星上的沙丘
Unlike the dunes we know and love on the earth
完全是由冰颗粒构成的
that are made of sand, the dunes on Pluto
与我们在地球上认识和喜爱的沙丘不同
are made entirely of particles of ice.
只有一件事可以建造沙丘——风
There's only one thing that can build dunes... wind.
沙丘就像是风在山谷中移♥动♥的视觉化呈现
Dunes are like a visual representation of the wind
它携带着沙子吹过山谷，留下沙子并沉积
that's moving across the valley and carrying the sands with it
最终形成这些巨大而美丽的沙丘形态
and depositing it into these big, beautiful dune forms.
我们的星球足够大
Our planet is large enough
可以容纳大气层
to hold on to an atmosphere.
当空气被太阳加温后会就上升
Air, warmed by the Sun, rises.
新鲜空气从下面补充进来，于是产生了风
Fresh air rushes in underneath, generating winds.
冥王星很小，离太阳很远
Pluto is so small and so far from the Sun,
不应该有大气层、风或沙丘
it shouldn't have an atmosphere or wind or dunes.
冥王星的问题
The problem Pluto has,
就像太阳系中的其他小天体一样
like other small bodies in the solar system,
很难保持住大气层
is that it's really hard for it to hold on to an atmosphere.
因为它太小了
It's just too small.
即使是非常稀薄的、轻的大气气体，也会轻易地逃逸掉
The very thin, light atmospheric gases basically just escape.
无论是妊神星或鸟神星
Neither Haumea nor makemake
都没有可探测到的大气层
have detectable atmospheres,
但是当新视野回顾冥王星时
but when new horizons looked back at Pluto
这颗矮行星在太阳前面经过
as the dwarf planet passed in front of the Sun,