行星（2019）

运行了将近40亿年
for almost four billion years.
如果在38亿年前生命刚刚诞生时
If I was to sit here on Earth 3.8 billion years ago
我坐在这里仰望夜空
when life began and look up into the night sky,
就可能会看到它跟今天一样
I would have seen it shining there as a point of light
在静谧的星空中闪耀 遥远又超然
the same as it looks today, distant and seemingly detached.
在漫长的时间里它始终未变 而地球则经历了
And it's remained that way for the vast expanse of time it's taken
自然选择的漫长进化过程
for evolution by natural selection
将最初产生的有机物变成了现在的纷繁生命
to transform those first populations of organisms into all this,
把地球变成了太阳系无垠荒漠中的
to transform the Earth into an oasis of life
一片生命绿洲
in the desert of the solar system.
但木星对地球的影响至今依然存在
But Jupiter's influence over the Earth remains to this day...
因为尽管它与地球相距甚远 鞭长莫及
..and that's because, despite its great distance from us...
但它却牢牢掌控着小行星带
..it retains a vice-like grip over the asteroid belt.
我们往住会很自然地
It's easy, I think quite natural,
把小行星带看作一个单一结构
to think of the asteroid belt as a single structure.
一个围绕太阳的岩石环
A sort of ring of rock surrounding the sun.
但它现在的模样并非如此
But that's not what it's like at all.
事实上 那里存在不计其数的岩石碎块
In reality, each one of those millions and millions of pieces
它们是沿着各自不同的轨道运行的
of rock is following its own individual orbits.
这段生动的模拟动画融合了
And this remarkable animation
人们10年来的天文观测结果
is made up of ten years of astronomical observations.
动画中的每个点都代表
And every point you see on this animation...
一颗小行星 也包括了所有的行星
..is a single asteroid, apart from all the planets.
你可以看到地球 火星和金星 围绕太阳急速旋转
And so you see Earth and Mars and Venus whizzing around the sun.
但有趣的是 你看木星
But the interesting one is Jupiter...
它就在小行星带外侧公转着
..orbiting just outside the asteroid belt.
你可以看到小行星带是跟随着
What you can see is that the asteroid belt
木星的节奏律动的
dances to Jupiter's tune.
可以说木星就是小行星带的指挥
It's the conductor of the asteroid belt, if you like.
这里有许多复杂的模式 但也有其内在结构
There are complex patterns here, but there's also structure.
产生这一切的原因就在于
And the reason for that is the delicate interplay
太阳引力和木星引力之间
between the gravitational pull of the sun
十分微妙的相互作用
and the gravitational force from Jupiter.
可能出现的情况是
Now, what can happen is that
由于两颗小行星的相互作用
perhaps because of an interaction between two asteroids,
也许是相互碰撞
perhaps they collide with each other,
也许是在各自轨道与木星排成一条直线
or perhaps on their orbit they line-up perfectly with Jupiter
由此获得额外的重力弹射
and get an extra gravitational kick,
这种结构势必会扰乱小行星的轨迹
those asteroids can be disturbed from this structure
将它们送入太阳系内层
and be sent inwards to the inner solar system.
木星正是通过这一机制实现了对靠近太阳的
And by that mechanism, Jupiter has a profound influence
几大行星的深远影响
on the planets closer to the sun.
大约一亿年前
Around 100 million years ago,
一颗直径大约10公里的小行星从小行星带被撞飞
an asteroid 10km across was ejected from the asteroid belt.
在木星引力的作用下
Dislodged by Jupiter's gravity,
它被送上一条与地球相撞的轨道
it was set on a collision course with the Earth.
小行星撞击地球形成了一团炽热的火球
When it struck, it generated a fireball so hot,
方圆1000公里内的所有生命顷刻间灰飞烟灭
anything within a 1,000km radius would have died instantly.
这次撞击导致3000亿吨♥硫磺
The impact threw 300 billion tonnes of sulphur
进入大气
into the atmosphere.
在接踵而至的“核冬天”
And during the nuclear winter that followed,
地球上75%的物种彻底走向灭绝
75% of all species were wiped from the face of the Earth.
强大的木星
In one fell swoop,
一下改变了地球的历史进程
Jupiter changed the course of our planet's history.
如今在地球上几个地方
There are a few places on Earth today
仍旧能看到这些失落世界的影子
where you can catch a glimpse of lost worlds,
那里看起来仍像数百万年前的地球
you can see Earth as it was millions of years in the past
可以一睹地球曾经的模样
and perhaps glimpse the Earth as it might have been.
这里就是其中一个去处
And this is one of them.
这里现在是美国科罗拉多平原
Today, this is the Colorado Plain,
海拔超过1000米
over a kilometre in altitude,
位于丹佛市以南 靠近落基山脉
south of Denver close to the Rocky Mountains,
可是如果在两亿年前 这里处于海平面高度
but 200 million years ago, this was at sea level.
是一个古老的湖泊 而那些失落世界的幽灵
It was an ancient lake and the ghosts of those lost worlds,
那些过去的印记仍能看到
the imprints of the past, can be seen over there,
因为在这里能发现成千上万的恐龙脚印
because there are literally thousands of dinosaur footprints.
这些就是恐龙的脚印
And here they are, the dinosaur footprints.
感觉这真的很不可思议
I find this absolutely remarkable.
这些是大型的蜥脚类恐龙脚印
This is the footprint of a sauropod dinosaur.
它属于大型食草恐龙 脖子很长
That's one of the big ones. The big herbivores with the long necks.
它们重量在30吨♥左右
This animal would have weighed about 30 tonnes.
身高差不多有两层楼那么高
It was tall enough to peer over a two-storey house.
我们可以想象的是 当时可能有一群蜥脚类恐龙
What happened here is, probably a herd of them, a group of them
行动笨拙地穿越湖床 随后
came lumbering across this lake bed and, then,
也许就在当天下午 紧盯这群恐龙的
perhaps that same afternoon, predators came,
捕食者尾随而来
maybe following the herd.
这些脚印就是异特龙留下
And that's these footprints here.
这是三趾脚印
The allosaurus', these three-toed footprints.
异特龙的体形要小得多 大概是我身高的两倍
Much smaller animal, maybe about twice the height of me,
体重大约两吨♥ 非常灵活敏捷
about two tonnes, very nimble and agile.
你在这里相当于看到了一个被时间冻结的完整故事
So, you see a whole story played out here, frozen in time.
如今的地球上只留下了它们的脚印
Today, just their traces remain...
但如果不是木星的缘故
..but were it not for Jupiter...
它们或许依旧倘佯在地球各处
..they might still be here.
在漫长的地球历史上
There are so many chance events,
甚至是长达138亿年的宇宙历史上
not only throughout the history of Earth,
发生过许多偶然事件
but also spanning the entire history of the universe
如果没有这些偶然事件 我们可能根本不存在
for 13.8 billion years, without which we wouldn't exist.
地球生命自从40亿年前诞生以来
There's an unbroken chain of life stretching back
就始终繁衍延续
four billion years here on this planet.
如果中间出现任何中断或干扰
You interrupt or interject at any point
地球生命就会发生变化
and life on Earth is different.
当然就像所提到的 还会有一些影响生命的重大事件发生
But having said that, there are major events that affected life.
其中之一就是小行星的撞击导致了恐龙的灭绝
And one of them is the asteroid that wipes out the dinosaurs.
从这个意义上我们可以说
And, in that sense, it is certainly true to say
如果没有木星 人类就不可能存在
that without Jupiter, we wouldn't be here.
这位太阳系的守护者冥冥之中为人类统治地球
The godfather of the planets paved the way for us
铺平了道路
to inherit the Earth.
虽然它偶尔还是会从小行星带
And although it occasionally flings rocks
向我们抛掷几颗石块
from the asteroid belt our way...
但它也在保护着我们
..it also protects us...
对于那些从太阳系最远
..because for objects heading towards the Earth
冲向地球的天体来说
from the far reaches of the solar system,
木星的引力场发挥着屏障般的作用
Jupiter's gravitational field acts as a shield.
大约100年前 一颗直径4000米
Around a century ago, a lump of rock and ice
重170亿吨♥ 由岩石和冰组成的彗星
4km across and weighing 17 billion tonnes...
朝着太阳系内层猛冲过来
..was hurtling towards the inner solar system...
此时木星大显威力
..until Jupiter intervened.
5 4 3 2 1 Five, four, three, two, one...
我们已经点火并发射“亚特兰蒂斯”号♥
We have ignition and lift off of Atlantis
搭载“伽利略”号♥前往木星
and the Galileo Spacecraft bound for Jupiter.
70年后 我们亲眼目睹了木星的
70 years later, we witnessed just how effective a shield
有效屏障作用
Jupiter can be.
美国国家航♥空♥航♥天♥局 “亚特兰蒂斯”号♥航♥天♥飞机 1989年
“亚特兰蒂斯”号♥航♥天♥飞机搭载的是
Onboard the space shuttle Atlantis...
“伽利略”号♥轨道探测器
..the Galileo orbiter.
苏梅克-列维9号♥彗星
在“伽利略”号♥探测器发射3年后
Three years after Galileo launched,
苏梅克列维9号♥彗星被木星的引力俘获
comet Shoemaker-Levy-9 had been captured by Jupiter's gravity.
它落入了这颗气态巨行星的怀抱
Locked in the giant planet's embrace...
并在潮汐力的作用下变得四分五裂
..tidal forces now began to tear it apart.
这颗彗星的旅程戛然而止
Its journey cut short...
等待它的是毁灭的结局
..the comet now faced annihilation.
1994年7月 距离木星2.4亿公里
“伽利略”号♥飞出内太阳系
After crossing the inner solar system,
穿过小行星带
Galileo passed through the asteroid belt...
逐渐接近即将见证这颗彗星
..approaching the spots from where it would witness
最后毁灭的地方
the comet's final moments.
美国国家航♥空♥航♥天♥局 “伽利略”号♥拍摄图像
7月16日 “伽利略”号♥观测到这颗彗星的首批碎片
On July 16th, Galileo saw the first fragments of the comet
落入了木星的南半球
enter Jupiter's southern hemisphere.
苏梅克列维9号♥彗星的碎片
Pieces of comet Shoemaker-Levy-9
撞击木星的过程持续了6天时间