了解宇宙是如何运行的（2010）

How the Universe Works S10E06

Part 5 Aug. 5, 2022, 5:05 p.m.

those beautiful outbound
pictures of Saturn
美丽照片
that you see.
随着旅行者号♥再次运行
With Voyager
operational again,
NASA同意为下一阶段的任务提供资金
NASA agreed to fund
the next stage of the missio
[海蒂]我永远感激 NASA 决定完成
[Heidi] I'm eternally gratef
that NASA did decide to
这次伟大的旅行
complete the grand tour.
知道我们有一个健康的宇宙飞船
It was tremendous
relief to know we had
a healthy spacecraft,
旅行者2号♥
Voyager 2,
能够去天王星和海王星，这是极大的宽慰
to go on to
Uranus and Neptune.
1986年
1986,
在土星的引力弹弓助推下
boosted by a slingshot
from Saturn,
旅行者2号♥到达天王星
Voyager 2 arrives at Uranus
在太空中待了9年之后
After nine years in space,
探测器现在进入了未知领域
the probe is now in
uncharted territory.
[卡莉]在旅行者号♥遇到天王星之前
[Carly] Ahead of
Voyager's encounter,
我们很难理解天王星身上的
Uranus was really
difficult to know much about
我们知道的颜色
We knew what its color was,
而且它没有任何来自地球的明显特征
but it didn't have any obvious
features from the Earth.
它看起来有点像一个普通的绿色斑点
It looked sort of like
a generic green blob.
我们确实知道一些事情
We did know
a couple things.
天王星有光环
Uranus has rings
位于它的一侧
and sits on its side.
[丹]其他大多数行星的旋转轴
[Dan] Unlike most of
the other planets,
都或多或少地垂直于它们的轨道平面
whose spin axis are oriented
more or less perpendicular
to their orbital plane,
而天王星不一样，它是倾斜的
Uranus is tipped over
on its side,
它有时会像桶一样绕着太阳旋转
it rolls around the sun
like a barrel at times.
还有一些时候，太阳正好照在赤道上
There are other times when
the sun is shining right dow
the equator.
这很不寻常
It's very unusual.
在历时五个半小时的飞行中
In a flyby lastin
just five and a half hours,
旅行者2号♥发现了11个新卫星
Voyager 2 discovers
11 new moons,
还有两个幽灵般的环绕天王星的光环
and two more ghostly rings
circling Uranus.
但旅行者2号♥最奇怪的发现是
But Voyager 2's
strangest discovery
这颗行星奇特的磁场
is the planet's freakish
magnetic field.
“旅行者”号♥携带了一个磁杆
Voyager carried
a magnetic boom
that told us about
它告诉了我们这个行星的磁场
the magnetic field
of the planet.
结果非常有趣
And that turned out to be
really interesting.
天王星磁场的强度和方向
The strength
and direction of Uranus'
magnetic field
与其他行星不同
turns out to be unlike
any other planet.
[菲尔]地球有磁场
[Phil] The Earth has
a magnetic field
它的行为是非常复杂的
and it's pretty complicated
how it behaves.
但你可以把它想象成行星内部有一个巨大的条形磁铁
But you can think of it as if
there's a giant bar magnet
inside the planet.
有一个北磁极和一个南磁极
There's a north magnetic pol
and a south magnetic pole,
它们周围有磁力线
and magnetic field lines
around them.
在地球上，条形磁铁与地球的自转轴紧密相连
On Earth,
the bar magnet lines up clos
to our planet's spin axis.
旅行者号♥探测器在土星和木星也发现了同样的情况
The Voyager probes foun
the same in Saturn
and Jupiter.
但是天王星的磁场却不同
But Uranus'
magnetosphere is different.
磁场的南北轴
The north and south axis
of the magnetic field
is tilted
相对于天王星的自转轴
by almost 60 degrees,
倾斜了近60度
relative to the spin axis
of Uranus.
这很奇怪
That's strange.
[丹]如果你想象把地球的
[Dan] If you imagine
transforming the Earth's
magnetic field to be like
变成天王星的磁场
the Uranus one,
你会在迈阿密附近的某个地方发现磁北极
you'd have the magnetic
north pole near
Miami someplace.
就在左外场的位置
It's way out there
in left field.
磁场不仅仅是倾斜的
And the magnetic
field isn't just tilted.
[丹]还偏离了中心！磁场的中心
[Dan] It's off center!
The center of
the magnetic field,
你认为应该在行星的中心
you think would be at
the center of the planet,
但实际上它偏移了5000英里(约8000多公里)
it's actually offset
by 5000 miles,
这偏得太多了
which is a lot.
我们认为它可能是在天王星的地幔中产生的
We think it may be generated
in the mantle of Uranus,
那里有熔融的水，而不是熔融的铁
where there is molten water,
not molten iron.
极端的高温和高压会使水分子分离
Extreme heat
and pressure breaks
water molecules apart
并使它们重新排列成一种熔融的晶体结构
and rearranges them into
a molten crystal structure,
这种奇异的状态被称为超离子冰
an exotic state called
superionic ice.
当我们说到冰的时候
When we talk about ice,
比如在一个巨大的行星上的巨大冰块
like, superionic ice
inside a giant planet,
但我们说的不是冰块[笑]
we're not talking about
ice cubes. [chuckles]
水有很多不同的存在方式
Water has lots of
different ways of being.
有些真的很奇怪
And some of them
are really strange.
半液态半固态的冰
The half liquid,
half solid ice
在星球的外层旋转
swirls around in the outer
layer of the planet,
像液态金属一样移♥动♥
moving like liquid metal.
由于冰导电、
Because the ice
conducts electricity,
这就产生了天王星周围的偏移磁场
this produces the offset
magnetic field around Uranus
旅行者2号♥还发现了一个巨大的磁故障
Voyager 2 also uncovered
a gigantic magnetic glitch
但它一直隐藏在数据中
but it remained hidden
in the data
直到2020年科学家才发现
until scientists discovered
in 2020.
[菲尔]他们发现的是一个光点
[Phil] What they found
was a blip,
磁场增强了
a strengthening of
the magnetic field,
在天王星后方大约一百万英里的地方
and it was about
a million miles behind Uranus.
不管是什么原因造成的，都是相当大的
And whatever was causing this
was quite large.
它是一个巨大的磁泡
It's a giant
magnetic bubble,
直径25万英里
250,000 miles across,
漂浮在太空中
floating in space.
[菲尔]这种类型的磁泡被称为等离子体
[Phil] This type of
magnetic bubble is called
a plasmoid,
当磁场线被挤压时
and it happens when
the magnetic field lines ge
pinched off
它就会产生类似于一个独♥立♥的壳
and it can create, sort of
a self-contained shell.
这意味着天王星周围的磁场
This means that
the magnetic field