宇宙（2007）

The Universe S01E08

Part 2 April 22, 2021, 8:12 p.m.

he drew in a drawingin place of a noun,
只有一幅图示
and this is what he drew.
这就是他所画的
Here's Saturn, andhere's these two things.
土星在这里, 这两个是他发现的东西
Unfortunately Galileo neverreally figured out what it was.
遗憾的是,伽利略并不确切知道这是什么
We had to wait for a laterastronomer to do that.
只能等今后的天文学家继续探索
45 years later, a Dutch physicist,Christiaan Huygens,
45年后,荷兰物理学家惠更斯
had an answer.
找到了答案
He knew that there wasn't justone ring, but several giant rings.
他认识到这些不仅仅是一个圆环是几条圆环
Today, there areseven know ring regions.
如今,我们知道里面有7个环区
There's the A-ring,the B-ring and the C-ring.
A环B环C环
So those are the threemain rings.
是3个最主要的环
There is a ring interior to theC-ring called the D-ring.
C环里面还有D环
And once we got there with Voyager,showed us the F-ring in all its glory.
当我们的先驱者号♥到达土星,发现了最美丽的F环
And then there were some diffuserings outside, the E and the G-ring.
在F环外还有微弱的E环和G环
Each of these ringshas a different personality.
每条环的性质都不一样
The A-ring is almost transparent,
A环几乎是透明的
which is why light easilypasses through it.
因为光线最容易穿透A环
The B-ring is dense,chock-full of material.
B环密度最大,充满物质
The C-ring is evenmore transparent than the A.
C环比A环还透明
While the D-ringis barely there.
而那儿,是D环
There's a lot ofneat things in those rings.
这些环里面有许多令人感兴趣的
So you can't think of them ashomogeneous body.
我们认为他们都是不同的
You gotta think of each particleinside those rings and what is ***
你可以想象一下这些由各种碎片组成的环
These distinct qualities are what wesee as colours, shapes and shadows.
就像我们所见颜色,形状和阴影各不相同
The wonder that isSaturn's rings.
神奇的土星光环
The reason we cansee them at all is due to the Sun.
我们能够看见它
Just as our moon glows withreflected sunlight,
是因为它像月亮一样反射阳光
so do Saturn's rings.
这是土星光环如此明亮的原因
It is a phenomenoncalled "ring shine".
这个现象称为环反射
Just imagine yourself on the nightside of Saturn looking up,
想象一下你在土星背面的黑夜中抬头仰望
and having the rings justcompletely covering the sky.
看见这些光环布满整个天空
It's much brighter than** the Earth on a full moon.
比地球上的满月亮很多
They shimmer, and they're brilliantand they're bright,
闪耀着,非常明亮
and that's because they're mostlymade up of ice particles
这主要是由于环由冰质碎片组成
which reflect a lot of sunlight.
反射了更多的阳光
However, there is evidence thatthe glowing marvels of our Solar System
然而,有迹象表明
这种太阳系奇观
won't be around forever.
也许不是永恒的
Some scientists are askingjust when will they disappear.
一些科学家猜测光环可能在某时消失
尽管科学家们对于土星光环
For all scientists know about Saturn'srings, they remain a huge mystery.
依然还有很多不明之处
这种猜想也受到质疑
When they appeared is a pointof much debate.
他们认为,环形成于土星诞生时
Scientists used to believe that the ringswere formed at the same time as Saturn.
约45亿年前
4.5 billion years ago.
但是,我们无法知道环上的物质还有哪些是最初形成时的
But because we don't understandwhat holds the rings together
我们最多只能猜测环还能坚持多久
and our best guess as to how longthe rings could stay together
也许还能存在几亿年吧
is only a hundred million years, there'ssomething wrong with this picture.
有理由相信
There are reasons to believe
土星环的寿命不会超过几亿年了
they're no older than a fewhundred million years old.
这个理由出自
Those reasons lie in trying to estimate
对环磨损消耗速度的预计
how much erosion is takingplace on the rings,
因为小陨石的不断袭击
because of the hailstormof micro-meteorites,
那些高速飞来的微小陨石
small, tiny bodies... particles
that come in at a tremendousspeed and chip away
袭击并损耗土星环
at the rings and thereforeerode them.
天王星,海王星和木星都有自己的环
Neptune, Uranus and Jupiter also haverings, but theirs are sparse and dim.
只是比较少和微弱
土星环是最明亮完整的
Saturn's are bright and full,
这导致科学家们思索
leading scientists to suggest
土星环可能没有被侵蚀太久
that they haven't been exposedto erosion for long.
也就是说,相对还很新
And therefore are relatively new.
但是,不断的侵蚀
But, does this gradual erosion
是否意味着土星最终将失去着最大的特征?
mean that Saturn will loseits most magnificent feature?
这种想法认为长时间以来
The idea is that over long periods oftime the material can get just so small
环的物质碎片将越来越碎小
如果你进入土星的磁力层
that it can be charged, and acquiring acharge in Saturn's magnetosphere,
会被磁力场拉出土星
and then it can just get zipped away,taken away by the magnetic field.
或者直接螺旋形掉进土星
Or it just spirals intoSaturn itself.
这是土星环的死亡阶段
That is a scenario forthe death of the rings,
it's that they finallyget eroded away.
将被慢慢消耗掉
因此土星环
In order for Saturn to continuouslyhave rings,
需要不断的补充
they need to be re-filled.
当前的土星环如此巨大
For the moment Saturn has atremendously large ring system,
但环的组成物质需要不断补充
but the actual material in the ringsdoes have to be replenished.
这样看来,另一种形式的袭击似乎是必须的
Strangely, another kindof assault might be necessary
才能维持环的存在
to preserve them.
必须要有彗星击中土星环
They have to get renewed byan errant comet coming in and crashing,
给环提供新的物质
adding to the massthat's going around there.
这个问题备受怀疑
And that kind of questionis still being debated.
环消失的理论在建立过程中始终充满争议
The debate continues when theorisingas to when the ring will vanish.
需要几亿年,也许几十亿年我不能确定
Hundreds of millions of years, probably,maybe billions of years, we don't know.
这个课题一直在讨论中
That's a matter of debateright now.
环到底是很年轻,然后很快就死亡
Whether the rings are young andare gonna die an early death,
还是已经存在很久了,也将继续存在很久很久
or they're old and they're gonna remainwith us for a very, very long time.
土星的48颗卫星中某些小卫星
Of Saturn's 48 named moons,there are small moons
被称作"牧羊犬"卫星
called "shepherds",for a good reason.
引力作用下他们围绕着某条土星环
They have gravitational pulls thathelp keep the rings intact
放牧
by herding the particles.
土星专家们被这土星的卫星和环之间复杂精巧的编排所吸引
Saturn's experts are interested in thecomplicated choreography
between the planet's moonsand its rings.
扭曲麻花般的F环特别引人关注
The contorted F-ringis especially intriguing.
两个牧羊犬卫星环绕在两边,普罗米修斯[土卫16]和潘多拉[土卫17]
And then there's the two shepherdsatellites on either side,
Prometheus and Pandora,
环被卫星引力作用
and they are having gravitationaleffects on this ring.
拉向几个方向
It's being tugged ina variety of directions,
看起来影响非常剧烈
so it looks wild and misbehaved,if you will,
这是动力变化作用区域
and it's a dynamicistsplayground.
我们对F环发生的这一切非常感兴趣
We're very, very interested inwatching what happens to the F-ring
因为这展示了卫星与环之间的相互作用
because it tells us how moonsinteract with rings.
土星早在公元前700年的古文明中被记载
Saturn mesmerizedcivilizations as early as 700 BCE,
亚述人记录了星空中明亮的土星
when the Assyrians took note of itsparkling in the distant sky.
数百年后希腊人称之Cronos
Hundreds of years later,the Greeks gave it a name: Cronos,
收获之神
after the god of harvest.
可能由于土星在收获的季节里处于天堂的位置
Possibly due to its position in the skyduring harvest season.
土星又是罗马神话的农业之神
The Romans' god of agriculture wasSaturnus, which is why we call it Saturn.
这就是现在土星[Saturn]的含义
也是由一星期的第六天来命名
They also named a day of theweek after him,
英语里的星期六[Saturday]
what we now call Saturday.
不过,如果罗马人近距离观察土星
However, had the Romans actuallyseen the planet close up,
可能会称之为天气之神
they might have named itfor the god of weather.
土星是一个狂热之处,时刻变化着
Saturn is a wild,ever-changing place but,
不像地球上的天气
unlike on Earthwhere things change
通常只持续几天或几小时
on a daily and evenon an hourly basis,
土星风暴能持续几天,几周甚至几个月
the storms on Saturn can lastfor days and weeks and months...
缓慢变化的巨大范围的天气
and things change on a large scalevery slowly over time.
土星剧烈天气现象的发现
The discovery of this violentactivity on Saturn
惊动了专家们
came as a surprise to experts.
几个世纪以来,土星的观测都不是那么清晰
For centuries, their viewof the planet had been obscured
土星大气中的大♥片♥氨气阻碍了观测
by an ammonia gas haze.
新的卫星数据改变了这一切
New satellite datais changing everything.
现在我们知道土星活力十足
And we see now that Saturnis a dynamic place.
被证明甚至比木星还要活跃的多
It's been revealed nowas being probably
more dynamicin a lot of ways than Jupiter.
仅仅就我们已经看到的那些风暴
There's the number of stormswe see, the motions that they do...
风暴的风速达到惊人的1000英里每小时[1600千米每小时]
Incredibly, winds blow at speedsof 1,000 mph.
实际的测量风暴
We measure the windsliterally by watching
需要观察小块的气体移♥动♥图像
the different little cells of theatmosphere move in imaging.
因此,从拍摄的图像
So you need sequentialimages
看看这些是怎样快速移♥动♥的
to see how much thingshave moved.
土星表面没有山
There are no mountainson the surface of Saturn,
仔细看看这些云的面貌
its cloud features that we look atto see how quickly
如何快速地变化,运动形成飓风
they evolve and change and moveto measure the winds.
最近的探索显示出
Recent exploration has shownother phenomena
一些目前难以理解的现象
that aren't yet understood.
我们可以看见这些面貌,云团和漩涡