了解宇宙是如何运行的（2010）

How the Universe Works S05E09

Part 4 April 18, 2021, 7:48 p.m.

the size of Jupiter.
取而代之的是
Instead, the dark knight must've started life far away
黑暗骑士一定是从远离恒星的位置产生
from the heat of its star,
那里是冰和气体丰富的地方
where ice and gas was abundant,
然后逐渐由外向内螺旋上升到
and then gradually spiraled inwards
现在的位置
to its current position.
我们认为这些热木星的形状
We think these hot jupiters form much
很像我们太阳系中的行星
like the planets in our solar system.
一颗巨大的行星
You have a massive planet
它的轨道离恒星很远
that's orbiting very far from the star,
从围绕恒星旋转的气体和尘埃盘中
building up material from this disc of gas
积累物质
and dust swirling around the star.
但是当它穿过这个气体和尘埃盘时
But as it's moving through this disc of material,
会猛地撞击这个盘
it's slamming into it.
于是形成了阻力
And that's acting like a drag.
所以就这样非常缓慢地
So very slowly, over millions of years,
在数百万年里
it's going to spiral into the star,
以螺旋的方式越来越接近恒星
get closer and closer and closer.
最后导致这颗巨大的行星
And what you're left with is a massive planet
它的运行轨道非常接近它的主星，变成一颗炽热的木星
orbiting very close to its star, a hot Jupiter.
Tres-2b 刚刚诞生的时候
Tres-2b most likely started life
很可能与今天的木星一样
looking much like Jupiter does today,
有非常明亮的颜色
bright in color
和一个有狂暴的暴风雨大气层
and with a raging, stormy atmosphere.
但当它靠近它的炽热恒星时
But as it moved closer to its hot star,
星球的大气层开始变热
the planet's atmosphere began to cook.
逐渐变黑，变成了黑暗骑士
It blackened and became the dark knight.
所以这向我们展示了
So this shows us how dynamic
行星系统的究竟怎样运行的
planetary systems must be.
行星会迁移
Planets migrate.
我们今天看到的行星
Where we see planets today
可能不是它们形成的地方
may not be where they formed.
事实上，我们很确定这不是他们形成的地方
In fact, we're pretty sure it's not where they formed.
感谢像 tres-2b 这样的奇怪星球
Thanks to strange worlds like tres-2b,
让我们确信气态巨行星
we now know for sure that gas giant planets
可以飘向他们的主星
can drift in towards their star.
但相反的事情会发生的吗？
But could the opposite be true?
它们有时会漂出星系吗？
Could they sometimes drift out?
天文学家把望远镜转向
Astronomers turn their telescopes
恒星之间的空间
to the spaces between stars.
他们惊奇地发现
And they're amazed to find scores
几十颗系外行星漂浮在开阔的空间
of exoplanets set adrift in open space.
这其中有一个孤独的孤儿行星
And one of these lonely orphan worlds
可能是我们见过的最奇怪的系外行星
could be the weirdest exoplanet we've ever seen.
2013年一群天文学家
2013 ... a group of astronomers
在夜空中搜寻一种叫做
scan the night sky for a mysterious class of object
棕矮星的神秘天体
called a brown dwarf.
棕矮星是失败的恒星
Brown dwarfs are failed stars,
由于体积太小
too small for fusion
所以无法发生核聚变点燃核心
to fully ignite in their cores.
但这些昏暗的气体星球确实会散发出一些热量
But these dim, gassy balls do radiate some heat,
使天文学家能够用红外望远镜
allowing the astronomers to pick them out
将它们分辨出来
with infrared telescopes.
恒星只是一个大的氢气星球
A star is just a big ball of hydrogen
它的质量刚好可以使内部的温度
that happens to have enough mass that the interior
升高到足以发生核聚变的程度
gets hot enough inside to start a nuclear reaction.
现在，宇宙完全有能力
Now, the universe is perfectly capable of producing things
产生一些质量不够大
that just didn't quite have enough mass
无法使核聚变发生的天体
to get those nuclear reactions going.
我们称之为棕矮星
And we call that a brown dwarf.
天文学家们的红外探测器
The astronomers get a hit
探测到了一些天体
on their infrared detectors.
但这不是他们所期望的
But it's not what they were expecting.
他们发现的天体质量太低
The object they see is too low-mass
不可能是棕矮星
to be a brown dwarf.
一定是一颗气体行星
It had to be a gas planet.
但它的主星却不见了
But its host star was nowhere to be seen.
这颗行星似乎漂浮在开阔的宇宙空间里
The planet appeared to be set adrift in open space.
天文学家偶然发现了
The astronomers had stumbled across one
银河系中最神秘的天体之一
of the most mysterious objects in the galaxy:
一颗孤独的流浪孤儿行星
A lonely, orphaned, rogue planet.
行星，顾名思义
A planet, by definition,
在某种意义上，你可能会认为
in some sense, you might've thought,
是围绕恒星运行的天体
is something that orbits a star.
但这些行星没有主星
These are planets that don't have a star.
流浪星球的想法简直是疯了
The idea of a rogue planet is just crazy.
如果我们还没发现他们
That's bonkers. And if ...
那一定会认为这个想法太疯狂了
but yet we've seen them.
所以这些东西是存在的我是说，现在我已经疯狂了
So these things exist. I mean, that already is crazy.
我们的星系可能有数十亿颗
Our galaxy could be home to billions of
游荡在星际空间的流浪行星
rogue planets wandering across interstellar space.
如果没有一颗恒星来给它们提供温度
Without a star to keep them warm,
你会认为流浪行星一定是寒冷的
you'd expect rogue planets to be cold.
但2013年发现的这颗行星非常怪异
But the planet discovered in 2013 is seriously weird.
它很热
It's hot.
在这个星球的厚重的大气层内部
The clouds in the planet's deep,
气体在华氏1400度（摄氏760度）以上高温下燃烧
gassy atmosphere burn at over 1,400 degrees fahrenheit.
很难想象到这种危险的地方去旅行
It's hard to imagine a more hostile place to visit.
现在，如果你试着进入这个星球
Now, if you were to try to get into this planet,
首先你能保护自己
if you could protect yourself from the massive amounts
不受大气对你的巨大压力
of pressure of the atmosphere
和试图蒸发你的巨大热量
squeezing on you and the huge amount of heat
对你的影响，即使这样
trying to basically vaporize you,
这里仍然会是一个相当粗爆的地方
it still would be a pretty rough neighborhood.
这里几乎肯定有令人难以置信的天气
This thing almost certainly has incredible weather,
巨大的风暴
tremendous storms,
大量的热空气上升和冷空气下降
huge parcels of hot air rising and cold air falling.
不仅如此，我们还发现
Not only that, we found that, in a lot of these objects,
在很多这样的环境中
if they're hot enough,
如果温度足够高，铁和其他金属会蒸发
iron and other metals can be vaporized.
当它们冷却的时候，这些东西会像雨一样掉下来
As they cool though, this stuff can rain out.
你可以想象滚烫的金属水的雨滴
And you can imagine droplets of molten iron
从空中落下
falling out of the sky.
这里绝对不是买♥♥公♥寓♥的好地方
This is not a great place to, you know, buy a condo.
在灼热的云层深处
Diving deep below the searing clouds,
压力不断增加
pressure builds
直到重力的压力变得非常大
until the pressure of gravity is so great,
以至于氢气变成了一种奇怪的液态金属
hydrogen gases transform into a weird liquid metal.
但是这个星球从何而来？
But where did this planet come from?
怎么会这么热呢？
And how did it get so hot?
这颗行星的灼热
The planet's scorching heat reminds scientists
让科学家们想起了
of infant gas giants in the hot,
在一个新形成的行星系统的炎热混乱环境中
violent crossfire
就有这样刚刚诞生的气态巨行星
of a newly forming planetary system.
这颗流浪行星是否有可能
Is it possible this rogue planet
就是一个婴儿行星被它的嫉妒的行星兄弟
was actually a baby thrown from its nursery
从它的育儿室扔了出来吗？
by its jealous planetary siblings?
行星显然是在恒星附近形成的
Planets obviously form in the vicinity of a star.
但是，你知道，在同一个窝里肯定有其他的行星
But, you know, they're in a nest with other planets.
在星系形成早期，它们过于接近时
And when they get too close in the early days,
它们的引力相互作用
their gravitational tugs
通常会使其中一些行星减速
will usually slow one of the planets down
而使另一些行星加速
and speed the other planet up.
如果加速的速度足够快
And if it speeds up enough,
那颗行星就有可能
that planet can escape the interstellar system
完全脱离星际系统并进入宇宙深处、处、处。。。
altogether and go out into the depths of space-Ace-Ace.
一个被遗弃的气体巨人婴儿
An orphan baby gas giant cast out into the cosmos.
但这个世界可能并不孤独
But this world may not be truly alone.
它可能有卫星
It could have companion moons.
在我们的太阳系中
In our solar system,
木星和土星的椭圆轨道上