宇宙（2007）

The Universe S01E08

Part 4 April 22, 2021, 8:12 p.m.

但是,随着惠更斯探测器穿越大气
But as the Huygens probe descendedthrough the atmosphere,
开始变得透明起来
it's transparent enough to beable to see the surface features
可以看清降落区域的地表特征
as it fell through.
跟洛杉矶的大雾没有太大不同
But it's not unlike a hazyday here in Los Angeles.
不是土卫六大气的颜色吸引科学家
It's not the colour of the atmospherethat most intrigues scientists,
而是其成分
it's the composition.
氮气和甲烷
Nitrogen and methane, the samegases they believe
正是早期地球大气的主要成分
made up much of Earth'searly atmosphere.
认为土卫六的大气
The idea that Titan'satmosphere
跟40亿年前的地球大气很相似
mimics the atmosphere of early Earth4 billion years ago,
激动着我们,让人很兴奋
it's something we're very, veryexcited about and interested in.
这是我们在实验室做过的最困难的实验
And it's one of the things we'restudying very hard in our laboratory.
看看是否能得到期待的结果
Let's see if we can get this aligned.What do we have?
科罗拉多州立大学,Margaret Tolbert博士
At the University of Colorado,Dr. Margaret Tolbert
正在他的实验室里模拟土卫六大气
is simulating Titan's atmospherein her lab.
是否其中包含着生命形成所需的元素?
Might it too have thenecessary ingredients for life?
在这个实验里,尽量模拟土卫六
In this experiment we're tryingto simulate the chemistry
大气顶部的气体成分
that goes on high in Titan'satmosphere,
也就是大雾之处
where the haze is forming.
这里有个反应室
So what we have is a reactionchamber here,
里面充满了氮气和甲烷
and all that we have here isnitrogen and methane.
土卫六大气的主要成分
So the two most importantcomponents of Titan's atmosphere.
然后我们只亮一盏灯
And then we're justgonna flick on a lamp,
这盏灯模拟太阳照射到土卫六大气上
and that lamp is going to simulate thesunlight hitting Titan's atmosphere.
令人惊讶地, Tolbert博士的研究
Incredibly, Tolbert's researchhas shown
显示出土卫六的大气
that Titan's atmosphere,
在模拟的阳光下
when stimulated by sunlight,begins to produce organic compounds.
开始产生一些有机化合物
这对于科学家在地球外寻找生物
For scientists looking for lifebeyond our planet,
非常的有帮助
this could be big.
当科学家们在银河系里寻找生命的迹象时
As scientists scour the galaxyfor signs of life,
这些令人激动的结果来自太阳系
there are some exciting resultsfrom within our own Solar System.
土卫六应该含有这些生命必需的物质
Saturn's moon, Titan, seemsto have the necessary ingredients.
科罗拉多州立大学的实验,表明阳光和富含氮气和甲烷的
Testing at the University of Coloradohas shown
that when sunlight interacts with Titan'snitrogen and methane-rich atmosphere,
土卫六大气共同作用
产生有机化合物
organic compounds are created.
这些有机物
So these organics are
飘浮在土卫六表面
floating down to the surfaceof Titan,
就像图片中那些
and you can see them in the pictures,
谁又知道这些化合物会创造出什么呢
and who knows what they'redoing once they're there?
也许能创造某些新形式的生命
They could be providing energyto some new kind of life.
还需要做更多的研究
Further research is needed
测定土卫六上是否真的有生命
to determine if there really islife on Titan.
或者能在某时进化出生命
Or if it might some daydevelop.
尽管土卫六大气非常相似早期地球大气
Although its atmosphere resemblesearly Earth,
但还是有很大不同
the environment is vastlydifferent.
这里很冷
It's cold.
低于零下华氏300度[-150度]
It's -300 篎and there's no liquid water.
没有液态水
这是土卫六和早期地球的最大不同
So that's a big difference betweenearly Earth and Titan.
土卫六上的河床和湖床
The lakes and river beds on Titan
是另外一些东西开凿的
were carved down to the groundby something.
这里没有液态水
There's no liquid wateron the moon,
那么,是什么在这里流动?
so what flows on this terrain?
地球上的山是硅酸盐石块构成
The hills on Earth are madeof silicate, rocks...
而土卫六上的山由冰和固态甲烷构成
whereas the hills on Titan areice, methane ice...
河道是甲烷雨造成的
The river channels on Titan areformed by methane rain,
不同于地球上流水形成的河谷
as opposed to the Earth river valleysformed by water.
显然,这里下着液态的甲烷雨
Liquid methane, it seems,rains down on Titan,
或者曾经下过
or did at one time.
土卫六温度太低一些气体都液化了
On Titan, it is so coldthat gases liquefied.
就有了河流湖泊
And there are coastlinesand rivers,
and all this terrain shaped bymoving rivers of methane.
这些地面河流都由
液态甲烷构成
这些非常令人好奇
It's just completely intriguing.
甲烷是天然气的主要成分, 还包含一些丙烷和丁烷
Methane is the principal componentof natural gas, butane and propane.
都是能源
All sources of fuel.
含碳油气都是燃料
There's a lot of hydrocarbons,
it might be very light hydrocarbons,on Titan.
土星六上发现的就是这些
含量很多
And there's a lot of it.
只要有氧可以永远燃烧下去
And it burns if you put it incontact with oxygen,
那里能量非常之多
so there's a lot ofenergy out there.
卫星表面的这么多能量
Enough on the surface ofthis huge moon,
可以满足很长时间人类的需求
to supply all of Earth's needsfor a very long time.
土卫六天然气储量非常大
Here is this tremendous supplyof natural gas on Titan.
能都带回地球那就太棒了
Well, wouldn't it be great to go outthere and tap into it and bring it back?
但是我想,这将耗资巨大
But I think that you would find thatit would cost you so much to go out
把甲烷提取并带回来
and get the methane andbring it back,
实际上你带不回任何东西
that you would never be able toeffectively power
anything on Earth with it.
尽管土卫六是土星最大的卫星
While Titan is Saturn'slargest moon,
不过某个小卫星也许更令人激动
one of its smallest maybe even more exciting.
土卫二,由明亮的冰岩混合组成
It's a brilliant ballof ice and rock called Enceladus.
它比较小
It's a tiny object,
直径只有300英里[480千米]
it's only about 300 miles in size.
体积只有月球的1/8
That's about 1/8th the sizeof our own Moon.
我们从没见过如此小的天体
And we've never seen a bodythat small
居然是活跃的
that has activity on it.
2005年发现了它的活力
This activity wasdiscovered in 2005
由卡西尼成像团队的Carolyn Porco博士发现
by Dr. Carolyn Porco and her Cassiniimaging team.
一幅照片上显示土卫二像个喷气式发动机
One photo seemed to suggestthat jets were coming out of Enceladus.
在我们团队看来很可能
It seemed very likely to the membersof my team that it's possible
这个喷气式发动机是个间歇喷泉
that these jets areactually geysers,
喷射水汽
they're erupting from pocketsof liquid water
喷气位置离表面不深
not too far beneaththe surface.
地球上与土卫二最相近的应该是
The closest thing we haveon Earth to Enceladus
黄石国家公园的Old Reliable喷泉
is something like Old Faithful geyserhere at Yellowstone National Park,
能把水汽喷上约100英尺[45米]高
which is shooting water vapourand water about 150 ft into the air.
而土卫二上的蒸汽喷泉能
The geysers on Enceladusare erupting
water vapour hundredsor miles into the air
在空中喷出几百英里高
是由于喷射猛烈而又没有大气阻碍
because there's muchlower gravity there
and the fact there's noatmosphere holding them in.
土卫二上被发现的很多喷泉
Many geysers have sincebeen discovered,
都位于南半球的一个区域内
all in a region of Enceladus'southern hemisphere.
产生于那些裂缝
They are coming outof these fissures,
这些巨大裂缝延伸有135千米长
big cracks that go on for about135 kilometres.
一些80英里长的裂缝
Something like 80 milesof cracks.
我们称之"老虎纹"
We call them "tiger stripes",'cause when we first saw them
因为我们第一次看见的时候
they really looked likethe stripes on a tiger.
发现这些纹路非常像老虎身上的
有4个区域布满裂缝
There're four areas thatseem to be ridges
应该都是地质活跃地区
or kind of active geologic areas.
这些区域喷射的水汽柱
And the plumes seemedto be coming out of these areas
大约有20或21根
and we counted about20 or 21 plumes.
土卫二的地面上都是太空Old Reliable喷泉
Southern Enceladus is coveredin cosmic Old Faithfuls.
谁能想到一个德克萨斯州大的冰球
Who would have thought thatan ice ball of the size of Texas
活力十足,不停喷发水柱和水汽
would be alive with plumesand geysers?
太令人惊异了
I mean, it's astounding.
土卫二由于土星的潮汐作用而被加热
Enceladus is heated in its interiorby the tides of Saturn.
月球引力作用于地球海洋
The Earth's Moon is pulling onthe Earth's oceans
拉升而造成潮汐现象
and distorting their shapeand producing the tides
这些现象我们很熟悉
that we're familiar withhere on Earth.
不过,土卫二在土星强大引力作用下
But on Enceladus, the planet Saturnis pulling on that moon
在围绕土星旋转的同时
and as Enceladus goes aroundin its orbit,
由于引力方向不断变化
that pull is changing the iceinside Enceladus.
土卫二内部不断碎裂摩擦
It's creaking and groaningand rubbing against itself
产生大量热量
and creating a lot of heatthrough friction.
我们认为这潮汐摩擦生成的热
We think it's that frictional heat
使冰水蒸发
that is producing the evaporationof the water ice that
从地表裂缝中逃逸,形成了我们所见的喷泉
is then escaping through these cracksand making the geysers that we see there.
另外
And there's more.
土卫二的喷发,证实了另一个理论
Enceladus' eruptionshave clarified a theory
关于土星某个环的形成原因
of what powers oneof Saturn's rings.