了解宇宙是如何运行的（2010）

The most important is also the most surprising
一个小小的冰卫星上可能有生命
A tiny ice moon that may be home to life.
有史以来
For most of history,
我们多半只能就近研究我们地球的卫星月球
The only moon we've been able to study up close is our own.
许多深陷的陨石坑是强烈冲撞的痕迹
Multiple deep craters tell a powerful story.
月球一片死寂
Our moon is dead.
它没有地质活动或天气系统
There's no active geology or weather
可以磨灭这些古老的伤疤
To wipe away these ancient scars.
但是其他行星的卫星呢
But what about the moons around other planets like saturn?
土星的卫星也是死寂的吗
Are they dead, too?
我们原本以为
Our first assumption about saturn
土星的卫星也跟月球一样
Was that the moons would be like that
寒冷死寂 是早期太阳系的遗物
Cold, dead, lifeless relics from the early solar system.
后来我们发明了宇宙飞船
It wasn't until we invented spacecraft
前往这些卫星才发现
That could go to these moons that we discovered
我们的太阳系有惊人的多样性
How incredibly diverse our solar system truly is.
土卫二 直径300英里的冰质卫星
Take enceladus an ice moon barely 300 miles across.
十年前没有人注意它
Nobody paid it any attention a decade ago.
但今天 它是宇宙探索的明星
But today, it's a geological rock star.
因为
And this is why.
土卫二的轨道在土星环的最外圈内的
Enceladus orbits inside saturn's outer most ring
E环运行
The e ring.
E环让科学家相当困惑 因为他们想不出
The e ring puzzled scientists because they couldn't figure out
这么宽广松散的环带为何不会消失
How a ring so broad and so diffuse Could hold itself together.
卡西尼号♥团队决定就近飞过土卫二
The cassini team decided to take a close fly by of enceladus
以解开这个谜团
To solve the mystery.
它是不是环粒子聚在一起的因素
Did it have something to do with keeping the particles together?
E环和土卫二又有什么关系
What was the connection between the e ring and enceladus?
现在我们知道
Well, now we know that enceladus is actually responsible
土卫二就是E环形成的主因
For the e ring being there in the first place.
2005年 卡西尼号♥拍到了令人惊奇的景象
2005, cassini captures an astonishing sight
土卫二南极的裂缝处 100座间歇泉
A hundred geysers shooting ice particles miles into space
将冰粒子喷到几英里高的天空中
From cracks in the south pole.
土卫二高速将内部物质喷进太空
Enceladus is hurdling its guts into space at a colossal rate.
在土卫二运行的时候
As enceladus orbits saturn,
这些冰质羽状物提供原料给土星外♥围♥的闪亮大光环
These icy plumes feed a vast shimmering halo around the planet
也就是神秘的E环
The mysterious e ring.
冰质羽状物也会和土星的磁场起相互作用
This icy plume also interacts with saturn's magnetic field,
形成带电粒子的电浆云
Causing a plasma cloud of charged particles.
带电粒子沿着土星磁力线高速行进
The particles race along saturn's magnetic field lines
撞进土星南北极的大气层
And slam into saturn's polar atmosphere,
造成辽阔的紫外线极光
Raising huge ultraviolet auroras.
间歇泉可以解释E环的形成
Geysers explain the e ring,
然后它是怎么出现在
But how can they exist on a frozen moon
离太阳几十亿英里外的冰冻卫星上的呢
A billion miles from the sun?
地球的间歇泉会出现在
On earth, geysers form in highly volcanic places
火山活动频繁的地方
Where water comes into contact with hot rocks.
土卫二很小 距离太阳又远
Enceladus, so small, and so far from the sun,
应该是死寂的冰冷世界
Should be cold and dead.
是土星的引力让它变热的
But thanks to saturn's gravity, it's not.
土卫二的热源
The source of the heating on enceladus
来自它的偏向轨道
Is the eccentric orbit of that moon.
有时它会离土星比较近
Sometimes it's a little closer to saturn,
有时它会离土星比较远
Sometimes it's a little further away.
这股引力会不断
And that heating on enceladus from that kneading
来回拉扯土卫二
Gravitationally making the moon stretch and pull
让内部的温度上升
Is what warms the interior,
造成我们今天在土卫二上看到的活动
Causing the activity on enceladus that we see today.
土星的重力
The gravitational pull of saturn
穿透土卫二的水冰地表
Reaches deep into enceladus beyond its water-Ice exterior
直达土卫二的岩石核心
Gripping its rocky core.
这股土星的引力时强时弱
As saturn's grasp strengthens and weakens,
它摩擦着土卫二寒冷的岩石核心
It massages this cold, rocky heart,
以摩擦产生的热能造成地质活动
Bringing it to geological life with frictional heat.
热能融化核心周围的冰
The heat melts the ice around it,
在地表下形成广阔湖泊
Creating a vast subsurface lake
水从土卫二南极
At the southern pole of enceladus.
地表冰层的宽大裂缝喷出
This water jets out through huge cracks in the surface ice.
在地球 有液态水的地方
On earth, where there's liquid water,
就有生命
There's life.
土卫二是否具备
Could enceladus have what it takes
让简单生命出现的条件
For simple organisms to exist?
卡西尼号♥拍到间歇泉之后
Once cassini saw these geysers, the scientists knew
科学家知道他们发现了极为美妙的现象
They had found something extremely wonderful.
他们甚至变更了卡西尼号♥的
They actually changed the mission of cassini itself,
任务跟路径
Changed its trajectory.
我们让卡西尼号♥低空飞到
We sent the cassini spacecraft to fly very, very close
这些间歇泉喷出的裂缝上方
Over these cracks where the water was rushing out.
科学家抱着渺小的希望
Scientists clung to the faint hope
或许那里的水分有盐分
That the water would contain salts and organic molecules
和氨之类的有机物质
Like ammonia,
这些分子是地球生命的基本成分
The building blocks of life here on earth.
惊人的是卡西尼号♥探测到大量的有机分子
Stunningly, cassini's censors tasted all of them in abundance.
羽状物里存在有机物
In that plume, there's organic material.
那不是水 那是原始汤
It's not water. It's a soup.
真是不可思议
That's incredible.
那里符合所有的居住条件
All the main requirements for habitability,
包括能量 液态水 生物氮和氨
Energy source, liquid water, source of biological nitrogen
的来源及有机物
And ammonia, organic material,
不断向太空喷发
And the samples are coming up into space.
就像一块写着免费赠送的大招牌
There's a big sign free samples, take one.
那里或许会演化出生命
There could be life that could've evolved there.
目前我们还不知道 还没发现过
Now we don't know. We haven't seen it.
但是目前那里的环境
But the conditions there are as good there now
就像30亿年前
As they were on earth 3 billion years ago
生命在地球形成的环境
When life arose here.
土卫二可能有生命的重大发现
The sensational realization that enceladus
让科学家为了接下来的探索任务
May harbor life has sparked intense debate
展开了激烈的辩论
About future missions to find it,
土卫二有个对手也在争取宝贵的研究资金
Because it has a rival for those precious research dollars.
因为土星最大的卫星 土卫六也可能有生命
Saturn's largest moon, titan, could also be home to life
而且是奇特的生命
Bizarre life.
我们可能早就发现它了
And we may have already found it.
绕行土星的卫星有60多个
More than 60 moons orbit the planet saturn,
其中有一个卫星特别雄伟
But one dwarfs them all.
土卫六是巨人 它比水星还大
Titan is a colossus, bigger than the planet mercury.
浓密的橙色大气层让望远镜无法观察土卫六的地表
A thick orange haze hides its surface from our telescopes,
卡西尼号♥首次看穿
And when the cassini mission first appeared beneath
土卫六的橙色大气层时 它所显示的世界
Titan's orange cloak, it revealed a world weirder
比我们想象的还要诡异
Than we could ever have imagined.
土卫六是个神奇的地方
Titan is an amazing place.
在土星的所有卫星里
And of all the things going on around saturn,
它或许是最令人兴奋的
Titan might be the most exciting of all.
土卫六有山脉 沙漠 河流和湖泊
Titan has mountains and deserts, rivers and lakes.
只有地球才有这么多样的地址特征
Only the earth can match it for geological diversity.
但土卫六的岩床其实是水冰
But here, water ice takes the place of bedrock,
温度低至零下300华氏度（零下149度）
Frozen at 300 degrees below zero.
而土卫六的河道里流动的
And instead of water,
不是水 而是液态甲烷
The rivers on titan flow with methane.
这里下的雨是液态甲烷
This is a place where it actually rains liquid methane,
就是液化气
Liquid natural gas.
这种液体填满了河流和湖泊
This liquid is filling up rivers and lakes.
因此土卫六极为特别
This makes titan incredibly special.
就我们所知 在太阳系中
It's only the second world in the solar system
只有它和地球的地表有液体
Where we know there's liquid on the surface.
和地球一样
And like earth,
土卫六具有富含氮的浓密大气层
Titan has a thick nitrogen-Rich atmosphere.
但是土卫六大气中没有提供呼吸的氧
But instead of the oxygen we breathe,
而是充满含碳的分子
Titan's air is spiked with carbon-Rich molecules
因此它呈现暗橙色
That stain it a dull orange.
那是甲烷 乙烷 丙烷