了解宇宙是如何运行的（2010）

How the Universe Works S01E07

Part 3 April 18, 2021, 7:57 p.m.

We've since decided that Pluto
is, in fact, a dwarf planet,
在超过30亿哩之外绕太阳运行
one of many orbiting more than
three billion miles from the sun.
哪里有数百万这样的行星
There are millions of
these things out there.
它们太遥远和太模糊, 很难看清楚
They're so far away and so
faint that they're hard to see.
这些是太阳系形成过程中的残留物
These are left over from the
formation of the solar system itself.
柯伊伯带处于太阳影响力的边缘
The Kuiper Belt marks the
edge of the sun's influence.
这里没有热力和光线极暗
There is no warmth and not
much light way out here.
但柯伊伯带并不是太阳系的边界
But the Kuiper Belt is not
the end of our solar system.
更远处还有一个由数万亿冰封物质
A shell of trillions of icy objects,
构成的外壳, 称为奥尔特云
called the Oort Cloud,
is even further out.
奥尔特云非常遥远
The Oort Cloud is so far away,
太阳的光要走一整年才能到达哪里
light from the sun takes
a full year to reach it.
从寒冷边缘到中心的炽热恒星
From the cold outer edge to
the hot star at the centre,
我们的太阳系看来很稳定
our solar system seems stable.
一切都井然有序和在怡当位置
Everything appears orderly
and in its proper place.
但有个地方令人♥大♥惑不解
But something isn't right.
天王星和海王星的位置不对
Uranus and Neptune
are in the wrong place.
太阳系的行星由气体和尘埃形成
The planets of the solar system grew
from a giant disk of dust and gas...
四个离太阳较近的岩态行星
the four inner rocky
planets close to the sun,
和较远的气体巨行星
and the giant gas planets farther out.
但天王星和海王星看来位置不对
But Uranus and Neptune
seem out of place.
离太阳这么远, 根本没有足够物质
There wasn't enough stuff
this far from the sun
形成这样巨大的行星
to make such big planets.
那么它们为何跑到这里呢?
So, what are they doing out here?
这引出了一个理论
That led us to a theory
天王星和海王星
where Uranus and Neptune
是在离太阳很近的位置形成
formed very close to the sun...
然后被推到了外♥围♥
and were actually
violently pushed outward.
是甚么推动两个巨大行星
So, what could shove two massive planets
穿越太阳系呢?
clear across the solar system?
我们相信土星和木星
We believe that Jupiter and Saturn
形成一种有趣的结构
got into this funny configuration.
木星绕太阳运行两周的时间
where Jupiter went around
the sun exactly twice
等于土星绕太阳运行一周的时间
every time Saturn went around once.
这种结构使得它们在相遇时
And that configuration...
产生更大的相互影响
allows the planets to kick each
other more as they pass one another,
这导致整个太阳系出现混乱
and that caused the
whole system to go nuts.
木星和土星的引力相结合
The combined gravity of Jupiter and
Saturn yanked hard on Uranus and Neptune...
猛力将天王星和海王星拖离太阳
and pulled them away from the sun.
当它们向外移♥动♥时
As they moved outward,
艰难地穿过小行星群
the two planets ploughed through
asteroids and other debris
和其它行星形成时留下的碎片
left over from the formation
of the other planets.
数十亿岩块在这过程中四处飞散
This sent billions of chunks of
rock flying in all directions.
有些形成了小行星带
Some rocks formed the asteroid belt.
但大部分被甩出外♥围♥形成柯伊伯带
But most were thrown out to
create the vast Kuiper Belt
我喜欢用保龄球赛做比喻
The analogy I like to use
is, think of a bowling match.
当保龄球打过去, 球瓶四处飞散
And the bowling balls go down,
and the pins just go kaplooey.
这就是在太阳系外♥围♥发生的情况
That's what happened in the
outer part of the solar system.
但木星和土星的引力太过强大
The gravitational push from
Jupiter and Saturn was so strong,
可能掉换了天王星和海王星的位置
it may have reversed the
position of the two planets.
天王星和海王星在形成时
It looks like it's possible... that
Uranus and Neptune actually formed
位置可能与现在相反
in the opposite order.
海王星比天王星更靠近太阳
Neptune was closer
to the sun than Uranus
但这些引力互动令它们掉换了位置
but these gravitational interactions
actually swapped their positions.
天王星和海王星穿过的大量岩石
It was the blizzard of rocks
that Uranus and Neptune ran into
起到了剎车作用
that acted like a brake
它们慢慢减速形成了现在的轨道
and slowed them into the
orbits they keep today.
行星改变轨道似乎匪夷所思
The idea of planets changing
orbits may sound crazy,
但科学家在其它太阳系见到过
but scientists have seen it
happen in other solar systems.
所以他们认为这是普遍现象
So now they think it's just
the way all solar systems work.
当我们遥望星系
When we look out into the galaxy
观察其它恒星周围的行星时
and look at planets around other stars,
看到许多类似事件发生过的证据
we see lots of evidence of those
kind of events happening elsewhere.
在一个遥远星系
In one far-off system,
科学家观察到超乎寻常的现象
scientists have spotted something
completely off the charts.,.
一个与木星同样大小的行星
a planet as big as Jupiter,
但它的运行方式与木星截然不同
but it's not acting
like the Jupiter we know.
有些这样巨大的行星
Some of these giant planets...
经常在靠近母恒星的地方运行
are found orbiting very
close to their host star,
只需几天时间就能绕母恒星一周
taking only days, a few days,
to go around the host star.
这些巨行星离恒星太近
Obviously, such close-in Jupiters
显然会受到炙烤
are blowtorched by the star,
行星的温度可达一千或二千度摄氏
raising the temperature of the planet
up to 1,000 or 2,000 degrees Celsius.
一个气体巨行星是不可能形成的
There's no way a gas giant
could have formed this close in.
这里的温度实在太高
It's way too hot
唯一的解释就是
The only explanation...
它在远处形成, 然后移♥动♥到这里
is that it must have formed out
there and then moved in here.
我们的太阳系可能发生过同样情况
The same thing could have
happened in our own solar system.
科学家已发现太阳表面…
Scientists have found large
amounts of the element, lithium,
含有大量锂元素
on the surface of the sun.
恒星中通常并没有锂元素
Lithium doesn't normally exist in stars,
但气体巨行星却含有这一元素
but it is found in gas planets.
也许我们的太阳系曾有气体巨行星
Maybe there was another gas
giant in our own solar system
撞向太阳
that spiralled in and
crashed into the sun.
这解释了为何太阳表面有锂元素
That would explain how
the lithium got there.
一定发生过激烈碰撞
Something very violent happened.
是否可能有一颗像木星大小的行星
Could it have been one of
these Jupiter-size planets
在很久以前撞入太阳?
getting thrown in
toward the sun long ago?
太阳系的初期狂暴而混乱
In the beginning, solar
systems are violent and messy.
但逐渐安定下来和变得较稳定
But over time, they settle
down and become more stable.
但稳定只是假象
But stability is an illusion.
太阳系里的任何一颗行星
Any planet in the solar system
随时都有毁灭危险
is always in danger
of total annihilation.
银河系中有各式各样的太阳系
There are all kinds of solar
systems in the Milky Way galaxy.
大多数与我们的太阳系大不相同
Most seem strange compared to our own.
有些行星的轨道很混乱
Some planets follow crazy orbits.
有些行星♥相♥互撞击
Some smash into each other.
有些甚至会撞入母恒星里
Others dive into their stars.
那么为何我们的太阳系的行星轨道
So why are the orbits of our own planets
如此规则和稳定呢?
so regular and stable?
因为所有行星的运动
Well, that's because... all the
planets have motion left over