了解宇宙是如何运行的（2010）

How the Universe Works S05E02

Part 5 April 18, 2021, 7:46 p.m.

no extra energy from the sun.
所以大气中任何重的物质，任何重的分子，
And so then anything heavy in the atmosphere,
随着时间的推移
any heavier molecule, over time,
很可能都会落到表面
would have probably fallen to the surface.
只有最轻的元素
And only the lightest elements,
最轻的分子，会留在大气中
the lightest molecules, would stay in your atmosphere,
所以可能只有纯氢和氦。
so maybe just almost pure hydrogen or helium.
你可能会有一个非常干净的环境
And you'd have, maybe, a really clear atmosphere.
德尔达:离太阳那么远的地方
Durda: What would a mini-Neptune look like
迷你海王星会是什么样子呢？
that far out from the sun?
我想到的是水母之类的东西，对吧？
The thing I think of are things like jellyfish, right?
那种美丽的，半透明的外观
That sort of beautiful, translucent look,
你甚至可以透过它看到生物体的内部
where you're looking through to the innards of the organism.
在这种情况下，你可以通过某种方式
In this case, you might look through
看到这个星球的内部
to the innards of the planet in some way.
大气层可能是透明的
The atmosphere may be transparent.
但这个星球远非平静
But this planet is far from calm.
星球内部会被雷暴的闪光照亮
The interior is lit by the flash of thunderstorms.
当来自遥远太阳的太阳风
And faint lights dance around the poles
沿着星球的磁场向下流动时
as solar winds from distant stars
微弱的光在两极周围飞舞
stream down the planet's magnetic fields.
杜尔达:观察这颗行星的内部
Durda: Looking into the innards of the planet,
在某些方面，它看起来
it would look, in some ways, like these gorgeous,
就像这些美丽的，发光的深海生物
beautiful deep-sea organisms that are bioluminescent.
我们可能会有类似于行星的东西
And we may have the planetary equivalent
存在于漆黑的太空中
of something like out there in the inky blackness of space,
而不是漆黑的海洋深处
rather than the inky blackness of the deep ocean.
9号♥行星会是一个迷你海王星吗？
Could planet 9 be a mini-Neptune?
令人惊讶的是，在我们的太阳系中存在额外气体巨星的
Surprisingly, the possibility of an extra gas giant
可能性并不是什么新鲜事
in our solar system isn't new.
2011年，科学家们
In 2011, scientists attempted
试图用超级计算机
to replicate the formation
模拟太阳系的形成过程
of our solar system using supercomputers.
但他们的模型是行不通的
But their models didn't work
除非他们再加上一颗巨大的气体行星
unless they added an extra gas giant planet to the mix.
再造我们现在的太阳系
It was really difficult to reproduce
真的很困难
our current solar system.
但一位科学家发现
But one scientist found that,
如果你在我们的太阳系中
if you add a fifth large planet
加入第五颗大行星
to our solar system,
那么这颗行星最终会
then that planet will end up
被我们的太阳系喷射出去
getting ejected from our solar system.
结果就会有我们今天拥有的行星了
And you'd have the planets that we have today.
9号♥行星是超级计算机预测的失踪的
Is planet 9 the missing gas giant
气态巨行星吗？
predicted by the supercomputers?
计算机模型显示
The computer model shows it being ejected
它是被木星的巨大引力喷射出来的
by the immense gravity of Jupiter.
但是9号♥行星是否有可能是被太阳的引力
But did planet 9 instead cling to our solar system
捕获而依附于我们的太阳系呢?
by the tips of its gravitational fingers?
有时，我们的数学模型
Sometimes, our mathematical models
预测了我们认为不可能的事情
predict things that we think are impossible.
然后我们找到它们了
And then we find them.
而且，我们已经知道
And, for a while, we've known that,
如果你把一个小型海王星
if you throw a mini-Neptune
放入混合行星的形成中
into the mix of planets forming,
这个模型就会更好
the models work better.
也许我们终于找到了那把钥匙……第9大行星
Maybe we found that key, finally ... planet 9.
我们知道巨大的行星会被抛来抛去
We know giant planets can get thrown around.
观察者甚至看到被喷射出的行星
Observers have even seen ejected planets
在恒星之间的空间中自♥由♥漂浮
floating free in the space between stars.
9号♥行星是否也遭遇了同样的命运呢？
Did planet 9 almost suffer the same fate?
这是完全有可能的
It's entirely possible that there could've been
可能是一颗比地球大的行星
a planet forming bigger than earth,
像一个“超级地球”
something like a super-earth, well on its way
顺利存在于气体巨头所在的
to becoming a gas giant
美妙的圆盘区域
in this wonderful area of the disk,
它本来可以木星一样吸引很多材料像
where it could've drawn in a lot of material
并成为一个巨型气体行星
and become a gas giant like Jupiter,
只是它与木星走得太近了
except it got too close to Jupiter.
在它能做到这点之前
And, before it could do that,
它就被木星的引力
it was gravitationally thrown away
从这个美妙的觅食地
from this wonderful feeding ground
抛到了外太阳系
out into the much sparser,
更稀疏、更贫瘠的沙漠里
more barren desert of the outer solar system.
9号♥行星真的是一个被放逐到
Is planet 9 really a frozen mini-Neptune
太阳系外荒地的冰冻迷你海王星吗?
banished to the badlands of the outer solar system?
现在，这是我们最好的选择
Right now, it's our best bet.
但还有一个选择
But there is one more option.
一些科学家认为
Some scientists believe
9号♥行星可能根本没有在太阳系内形成
planet 9 may not have formed around our sun at all.
我们的这颗最遥远的行星
Is our most distant planet
是从另一颗恒星上掠夺来的外星世界吗？
an alien world snatched from another star?
如果这颗神秘的9号♥行星存在的话
If the mysterious planet 9 exists,
它是目前太阳系中
it is by far the most distant planet
距离最远的行星
in the solar system,
是海王星距离的20倍
20 times farther out than Neptune.
那么它是怎么来的呢？
So how did it get there?
它是在它目前所在的地方制♥造♥出来的吗？
Was it made in the place it currently occupies?
或者它是作为一个岩石性质的超级地球
Or was it flung out from the inner solar system
或者更有可能是
as a rocky super-earth
一个迷你海王星从太阳系内部
or, more likely, a mini-Neptune?
被抛出来的吗？
The jury's out.
但还有另一个选择
But there is another option.
它是来自系外的天体
And it's out of this world.
所以问题是，如果这两种说法都不对
So the question is, then, where did it come from
那它从何而来?
if neither of these things is right?
可能还有另一种解释
And it's possible that there is another explanation.
那就是第九颗行星是
And that is that planet 9 is an alien visitor
来自外太空的“外星人”
from outer space.
太阳只是银河系中
The sun is just 1 of 200 billion stars
围绕超大质量黑洞运行的
orbiting the supermassive black hole
2000亿颗恒星中的1颗
at the center of the milky way galaxy.
这些恒星中的大多数都有可能有多个行星
Most of these stars probably have multiple planets.
科学家们现在相信，有时，
And scientists now believe that, from time to time,
两颗恒星可能会靠得太近而让人不舒服
two stars might pass a little too close for comfort.
结果……就有了行星窃贼
The result ... planetary theft.
我们知道太阳在银河系中运行
We know that the sun moves around in the galaxy.
我们知道银河中
We know that there are other stars
还有其他恒星系
and other solar systems.
有没有可能是因为太阳
Is it possible that the sun passed so close
离另一个恒星系太近了
to another solar system
所以偷了一颗行星？
that it stole a planet?
今天，我们的太阳独自漂浮在太空中
Today, our sun drifts through space alone,
就像大海上的一艘游艇
like a yacht in the open ocean.
但事实并非总是如此
But that wasn't always the case.
时光倒流46亿年
Rewind the clock 4.6 billion years,
我们所在的星团是一个更加拥挤的地方
and our local star cluster was a much more crowded place,
这是9号♥行星跳船的理想条件
ideal conditions for planet 9 to jump ship.
太阳和其他成千上万颗恒星
The sun was born in a nursery
一起诞生在“恒星托儿所”
with thousands of other stars.
就像这个港口的船一样
Just like the boats in this harbor,
周围有很多船，很多邻居
there are so many boats around, so many neighbors.
年轻的太阳就是这样
It was like that for the young sun.
像太阳这样的恒星诞生于恒星的摇篮
Stars like the sun are born in stellar nurseries,
巨大的气体云
vast clouds of gas that collapse
坍缩形成成千上万的恒星
to form tens of thousands of stars,
所有的恒星都紧紧地挤在一起
all tightly packed together.
天文学家认为，在这个
Astronomers think it's possible
狭窄而混乱的恒星游乐场里
that, inside this cramped, confused playground of stars,
太阳的引力可能从路过的邻居那里
our sun's gravity could've stolen planet 9
偷走了9号♥行星