了解宇宙是如何运行的（2010）

We could not have been more wrong.
这个行星热闹非凡 有活跃的天气
The planet boils and bangs with active weather
风暴 闪电和极光
Storms, lightning, and auroras.
它的环一直在演化
The rings constantly evolve.
而它的卫星也并非我们所想的冰冻雪球
And the moons aren't the frozen snowballs we expected.
这些卫星受到地质运动的影响 有温暖的间歇泉
They're shaped by active geology with warm water geysers
还有液态甲烷湖泊
And lakes of liquid methane.
如今 在土星最大的卫星土卫六
And now on saturn's largest moon, titan,
科学家或许已经找到证明外星生命存在的
Scientists may have uncovered the first tangible evidence...
第一个确切证据
of extraterrestrial life.
液态水向来是我们寻找生命的重点
Our search for life has been
跟着水找
Focused on liquid water follow the water.
这是很棒的策略
I think it's a good strategy.
但是只找有水的地方
But i think we are limiting ourselves if we think that
这种做法未免狭隘
That's the only place to look.
我认为就算不是水的液体都有可能
I think liquids may be interesting even if they're not water.
克里斯麦凯是天体生物学家
Astrobiologist, chris mckay,
他认为土卫六演化出来的生命
Believes that life on titan
或许生活在液态甲烷里
May have evolved to live in liquid methane,
而并非活在液态水里
Not liquid water.
但是土卫六非常冷
But titan is so cold,
简单生命会有截然不同的生存法则
Simple life would play by a very different set of rules
那就是越大越好
Where bigger is better.
我们到其他星球时
When we go to other worlds,
会寻找那里有没有细菌
We're gonna be looking for bacteria,
我们会假设那些细菌很小
And we assume that they're gonna be very small.
但是你可以问 为何细菌会这么小
But you could ask the question, why are bacteria so small?
我想原因是它们生活在水里
Well, i think the answer is because they live in water.
地球的细菌不必长得很大
On earth, bacteria don't need to grow big
就能活的很好
In order to thrive.
水几乎可以溶解一切
Water dissolves almost everything,
它提供富含营养的环境
So it provides a nutrient-Rich environment
就连小而简单的生物也能存活
Where small and simple bring success.
土卫六有液态甲烷和液态乙烷
You go to titan where the liquid is liquid methane,
它们和水很不一样
Liquid ethane, very different from water.
所以生物不可能长得很小
There's no reason an organism should be small.
事实正好相反 它会长得很大
In fact, quite the opposite. It should be huge.
麦凯想象土卫六有巨大的单细胞生物
Mckay envisions enormous single-Celled organisms
长得和纸片一样
Around titan's shores, looking like sheets of paper.
它们会用巨大的表面♥积♥尽量摄取食物
Their huge surface area would maximize
因为液态甲烷的养分很低
The uptake of food from the nutrient-Poor liquid methane.
我预料如果土卫六上
I predict if there's life on titan
你不需要显微镜来观察
Living in liquid methane, you won't need a microscope to see it.
你需要米尺
You'll need a yardstick.
但卡西尼号♥在土卫六云层上方
When cassini released the huygens probe
投放惠更斯号♥时
High above the cloud tops of titan,
麦凯发现他有机会
Mckay realized he had an opportunity
让他的土卫六生物理论更有说服力
To bolster his theories of life on the surface.
他说想象的甲烷生物必须进食才能存活
His methane-Loving life-Forms must be eating to survive.
或许惠更斯号♥灵敏的传感器
Perhaps huygens' delicate sensors
会搜集到生物进食的证据
Would pick up evidence of ground level feasting.
惠更斯号♥前往土卫六的路上
As huygens was on its way to titan,
我正在旅馆里写论文
I'm sitting in a hotel room writing up a paper saying,
我写 要是土卫六上有生命呢
Hey, what if there's life on titan?
它会吃什么 我们要怎么才能发现它
What would it eat? And how would we detect it?
这个穿过大气层的探测器
How would this probe flying through the atmosphere
如何检察
Detect it?
就在惠更斯号♥登陆的当天
Literally the day huygens landed,
我把这篇论文投到期刊
I submitted this paper to the journal,
并且预测如果土卫六有生物
Predicting that if there was life on titan,
它的食物应该是氢
It would eat hydrogen and the probe
探测器应该会发现氢被消耗
Would be able to measure this depletion of hydrogen.
所以我们要测量氢的含量
So let's look for hydrogen.
惠更斯号♥打开降落伞
Huygens parachutes through titan's atmosphere,
穿越土卫六的大气层并沿途采集氢样本
Sampling the gases as it goes.
高层大气有大量的氢
The upper atmosphere has plenty of hydrogen,
中层大气也是
So do the middle layers,
然而地面却出现意外的结果
But at ground level, there's a surprise result
空气的氢浓度明显下降
An apparently drop-Off in the concentration of hydrogen in the air.
某种物质或某种生物把氢用光了
Something or perhaps someone was using it up.
我一听到报道说地面的氢被耗尽了
When i heard a report that there was a depletion of hydrogen,
心跳就变得好快 我心想
I my heart raced 'cause i thought,
如果有确切数据
If this is if this is hard data
证明氢被耗尽
For depletion of hydrogen,
除了被生物消耗掉外 我想不出其他理由
I can't imagine any other way besides biology to explain that.
我很兴奋 因为结果
It's exciting in that it's consistent
和我们预测一致
With what we predicted,
但是我们需要其他的计算结果
But we have to wait for this to be confirmed
跟直接的测量来进一步证实
By other calculations, by direct measurements, and so on.
如果未来的任务能证实土卫六有生物活在甲烷里
If future missions can confirm methane-Based life
那绝对会是科学史上最伟大的发现
On titan, it will surely be the greatest discovery in the history of science.
因为这种低温环境的生物
Because this low temperature biology must have arisen
绝对不会是来自地球的生命
Independently of life on earth.
如果我们 比如在火星发现生命
If we discover life, let's say on mars,
它很可能来自
There will always be the possibility
地球和火星交换的岩石
That rocks and ice and bits of material
冰河物质
Could've been exchanged.
但是地球不可能和那么遥远的
But the chances of that happening from earth
土星交换物质
All the way to saturn are next to nothing.
要是我们能在太阳系
If we find a second example of life in our solar system
发现第二个有生命的地方
Especially in a place like titan
尤其是像土卫六这种和地球天差地远的寒冷环境
Which is so alien to the earth, so cold and so different,
那就说明了一件重大非凡的事情
That tells us something excruciatingly important.
生命必然存在于宇宙各处
And that is that life must be everywhere in the universe.
机器人任务发现了土卫二和土卫六
Robotic missions offer tantalizing hints
可能有生命的线索
Of simple life on enceladus and titan.
然而土星领域是否只适合巨大细菌生存
But is saturn's realm only fit for giant bacteria
它是否能成为人类的家园
Or is it a place we humans could one day call home?
土星轨道离太阳有十亿英里远
Saturn orbits a billion miles from the sun.
远到它的反射光要过一小时
So far out it takes an hour for its reflected light
才会到达我们眼前
To reach our eyes.
然而在我们文明的未来
Yet the future of our civilization
或许得靠人类殖民到
May rest on humans one day colonizing the moons
这个气体巨行星周围的卫星
Surrounding this gas giant planet.
这是艰巨的任务 然而土星
It won't be easy, but saturn has something
值得我们大费周章
Worth the trouble
因为那里蕴藏着丰富的氦三燃料
A magical source of fuel called helium-3
可以满足我们直到千百万年后
That can satisfy our increasing hunger for energy
不断增长的能源需求
For millions of years.
有些科学家认为
Some futurists believe that we have to have
土星旅行需要有商业价值
A commercial incentive to going to saturn.
不只可以到土星的卫星采矿
Not just to mine the minerals of the moons of saturn,
还可以去收集大量的氦三燃料
But also to harvest fuel in the form of helium-3.
氦三四非常罕见的物质
Helium-3 is a rare substance that we can use
可以用在聚变反应中提供无穷无尽的能源
In fusion engines to provide perhaps unlimited energy.
氦三是一种有单中子和双质子的物质
Helium-3 may very well replace oil as the fuel
非常适合取代石油燃料
To take us into the centuries to come.
为将来世界提供能源的物质
With its single neutron and twin protons,
氦三非常适合一种用来制♥造♥能源的方式
Helium-3 is uniquely suited to a form of energy production
那就是核聚变
Called fusion
也是在恒星核心里燃烧的过程
The same process that burns in the heart of a star.
当两个原子核
When two nuclei are crushed together
在高压下互相碰撞
Under enormous pressure, they fuse,
就会聚变成更重的新原子 并且释放出纯粹的能量
Creating a new heavier atom and a burst of pure energy.
最棒的是氦三不会释放出
Best of all, helium-3 doesn't release
和其他聚变燃料反应时
Any of the harmful radiation
释放出的有害辐射
Associated with other fusion fuels.
氦三只有一个问题
The only trouble with helium-3
它在地球的蕴藏量少之又少
There's precious little to be found on earth.
你可以在月球找到一些氦三
Now you could find some helium-3 on the moon,
但在我们的太阳系最大的氦三蕴藏地