了解宇宙是如何运行的（2010）

了解宇宙如何运行
第三季
土星
耀眼 传奇
Dazzling, legendary
它是夜空中最美丽的星球
It's the most beautiful planet in the night sky.
但是土星一直对我们隐藏着它的秘密
But secretive saturn has been holding out on us.
在我们了解到的关于它的事实中
We learned a vast amount about it,
大多数的已经非常令人吃惊
And most of this has been very surprising.
我们认为我们已经了解了它的大部分事实
We thought we knew those bodies. We had no idea.
土星有极端的天气
Saturn boils with extreme weather
波动和扭曲的
And weird lights.
奇异光环
The rings ripple and twist,
以及超过60个非凡的卫星
Bullied by over 60 remarkable moons.
每个卫星都是一个世界 都有值得一讲的故事
They are individual worlds. They each have a story to tell.
这是行星旅行的梦想
This is a planetary explorer's dream.
今天 土星的卫星
Today, saturn's moons
是寻找外星生命的热门
Are the hottest property in the search for alien life.
如果要我选择太阳系中
If there's one place in the solar system
最有可能存在生命的地方
I would put a bet that life exists there right now,
我选择土星
I would choose saturn.
在土星最大卫星上
And on saturn's largest moon,
我们可能已经找到了生命
We may have already found it.
我们在土卫六上有些奇怪的事情
We've found some curious things on titan,
很可能就是生命存在的证据
And it might just be evidence of life.
土星 夜空中的宝石
Saturn, the jewel of the night sky,
有着美丽的外观和巨大的体积
Dazzles us with its beauty and scale.
它是如此巨大
It's huge so big,
装得下700多个地球
You could fit more than 700 earths inside it.
但是不要被它的体积欺骗了
But don't let size fool you.
土星有一件事情很有意思
One of the most interesting things about saturn
虽然它体积巨大 但里面的物质并不多
Is that it is so big compared to how much stuff is in it,
这让它的密度比水还要低
That it's actually lower density than water.
有个土星的老笑话 如果你找得到足够大的浴缸
The old joke is that if you could find a bathtub big enough
把它装满水
And fill it with water,
土星会浮起来 而土星环会沉下去
Saturn would float, but it would leave a ring.
其他行星也有环
Other planets have rings,
但都没有土星这么宏伟壮丽
But none so vast and glorious as saturn's.
从主环外侧到内侧
The journey from the outside of the main rings
足足有6.6万英里（约10.6万公里）
To the inside edge is 66,000 miles
相当于地球周长的2.5倍
Over 2 1/2 times the distance around the earth.
然后这片尘埃和冰粒子的
Yet this vast collection of dust and ice particles
巨大集♥合♥体很薄 某些区域只有几十英尺厚
Is whisper-Thin in places just tens of feet.
土星环大部分
Saturn's rings are made up
很小的冰粒子和岩石组成
Of mostly very small particles, of ice and rock.
有的粒子很大
Some of the particles are larger,
但是绝大多数和沙子一样细
But for the most part, no bigger than grains of dust.
土星环的内外
Racing within the rings
有60多颗卫星在远距离运行
And orbiting far outside them are over 60 moons
它们由岩石和水冰组成
Made from rock and water ice.
最小的卫星和小雪球一样
They range in size from tiny snowballs
最大的卫星则有活跃的地质现象
To worlds with active geology,
液态水
Liquid water...
天气系统 甚至可能有生命
weather systems, and possibly even life,
存活在距离太阳十亿英里（16亿公里）外的这种地方
A billion miles from the warmth of the sun.
那里温度很低
It's so cold out there,
我们以为什么都没有
We just thought there'd be nothing there,
结果我们大错特错了
And we were so wrong. We were so wrong.
土星第一个令人意外的现象
Saturn's first shocker
就是土星的狂暴天气
Its wild weather.
土星的风暴极度猛烈
The storms on saturn are extremely violent,
我们地球上的风暴根本比不上
Unlike anything we see on the planet earth.
事实上 在整个太阳系中
In fact, saturn has the second fastest winds
土星的风速排名第二
In the entire solar system.
强风从土星的云顶呼啸而过
These winds race through saturn's cloud tops
时速超过一千英里（约1600公里）
At over a thousand miles an hour,
是地球上最强气旋的四倍
Four times faster than earth's strongest cyclones.
土星上有强度高达地球上一万倍的
And lightning bolts flash up to 10,000 times more powerfully
闪电
Than those on earth.
土星的一切都比地球大得多
Everything on saturn is just so very, very much bigger.
那里的天气系统
I mean, there are weather systems
比地球上的更大
That are as big or bigger than the earth.
土星的狂暴天气出人意料
Saturn's ferocious weather is surprising,
因为地球的天气
Because on earth, weather is driven
是由太阳的热能所驱动
By the heat energy of the sun.
太阳的热能让海水蒸发
The sun warms the land, generating wind.
形成雨和云
It causes the seas to evaporate, creating clouds and rain.
土星离太阳太远 不可能得到相同的热能
Saturn lies too far from the sun to feel the same warmth,
由此驱动其天气的热能
So the heat that drives its weather
必然来自别处
Must be coming from somewhere else.
为了了解这个神秘的热能来源
To understand this mysterious heat source,
我们必须回到45亿年前
We need to go back 4 1/2 billion years...
那时候带环的土星刚诞生
to the birth of the ringed planet.
我们太阳系的行星发源地
The planets in our solar system
由冰 尘埃和气体
Emerged from a vast, swirling cloud
组成的巨大旋涡
Of ice, dust, and gas.
今日还能在地球上找到这些成分
The same ingredients can still be found on earth today
例如冰岛等地方
In places like iceland,
这里的火山灰灰跟冰河混在一起
Where volcanic ash mixes with icy glaciers.
如果你想打造土星那样的巨大行星
If you wanna build a giant planet like saturn,
这堆原料就很适合用来说明
This pile of raw material here is a great visual analog.
宇宙间有大量的氧和氢
There's a lot of oxygen and hydrogen in the universe.
它们会形成水和水冰
That makes water, and that makes water ice,
最早形成太阳系的物质
And the stuff initially that made the solar system
就是这堆东西
Is basically this stuff here.
有肮脏的水冰
It's dirty ice, water ice, with a little bit of
冰里有一点岩石跟金属矿物
Little bit of rocky and metallic minerals left in there
这些都存在于寒冷的太空里
Out there in the cold of space.
45亿年前
4 1/2 billion years ago,
巨大的肮脏冰粒子云团
A vast cloud of dirty ice particles
被氢和氦裹住 并因为自身的引力而坍缩
Shrouded in hydrogen and helium collapses under its own gravity,
在中心形成新的恒星
And at the center, a new star our sun
我们的太阳系因此形成
Sparks into life.
这个新恒星的高温融化了最近的冰
The heat of the new star melts the ice closest to it
并吹散了气体 只留下岩石碎屑
And blows away the gas, leaving only rocky debris behind.
但在更遥远的地带 冰物质和气体留了下来
But farther out, icy material and gas survive.
冰冻线出现
A boundary forms a frost line
这条边界的内侧有岩石云团 外侧则有冰和气体
Between the rocky inner cloud and the icy gas beyond.
我们可以用营火来打比方
Once you fire up that campfire, if you will,
在内太阳系 只有这些东西会留下来
What would be left behind in the inner solar system
这是硅酸盐矿物质
Is gonna be this stuff
可以组成地球等行星
Silicate minerals you make a planet like the earth from.
但是离太阳更远的地带温度较低
But far away from the sun, where it's colder,
当你跨出了冰冻线
You cross the frost line, and what's out there
那里冷到足以让冰留下来
Is still cold enough to maintain the ice behind,
那里有很多冰
And there's a lot of it there.
起初这些材料会形成固体核心
At first you make sort of a solid core of this material,
等它累计到临界重量
But when you reach a critical mass,
就会产生足够的引力
You've got enough gravitational influence
开始直接吸引内行星云团的氢和氦
To start to directly draw in some of the hydrogen and helium In the interplanetary cloud.
土星巨大的固体核心
Saturn's huge solid core,
如今是地球的10到20倍大
Now 10 to 20 times the size of the earth,
它不断产生引力 吸引气体
Generates relentless gravity and draws in gas.
这个气体行星越大 就能吸引越多物质
The bigger this gas ball gets, the more material it sucks in.
接着土星强大的引力
Saturn's massive gravity then gets to work
开始将刚形成的大气层压缩
On its fledgling atmosphere, compressing it.
之后就跟受到压力挤压的气体一样 温度升高
And like any gas under pressure, it gets hot Seriously hot.
即使在今日 土星的高压大气
Even today, saturn's high pressure atmosphere
还是能让核心温度高达华氏2.1万度（约1万1千6百摄氏度）
Heats its core to 21,000 degrees
这是太阳表面温度的2倍
Twice the temperature of the surface of the sun.
这股上升的热能
And it's this heat rising up
形成了独特的土星环
Which forms saturn's distinct bands
并驱动着极端的天气