行星（2019）

美国国家航♥空♥航♥天♥局“信使”号♥水星探测器发射升空
Lift off of Messenger on Nasa's mission to Mercury.
水 星
金 星
火 星
木 星
土 星
天 王 星
海 王 星
行星 第3集
沿着内太阳系向外
Beyond the inner solar system...
穿过小行星带
..past the asteroid belt...
木星便映入眼帘
..lies Jupiter.
木星 距离太阳7.8亿公里
它是太阳系中体积最大的行星 一颗气态巨行星
The largest of the planets is a giant swirling ball of gas...
它表面斑驳的花纹是肆虐的风暴
..its marbled appearance generated by violent winds
经过木星云层时形成的
that rage through its clouds.
木星是一个既陌生又遥远的世界
Jupiter is a world as strange as it is remote.
如果你向上空飞行大约100千米左右
If you fly upwards, only about 100km or so,
你就能到达大气层边缘和漆黑的太空
you reach the edge of our atmosphere and the blackness of space.
距离并不遥远
It's really not that far.
可一旦置身太空
But once you're in space,
衡量距离的尺度就变得超乎想象
the distance scales are sort of incomprehensible.
金星是距离地球最近的行星 大约为4000万公里
I mean, Venus, the closest planet, is over 40 million kilometres away.
木星离地球大约为6.5亿公里
Jupiter around 650 million kilometres.
飞行最快的探测器也要数年才能到达
It takes our fastest spacecraft years to get there.
所以其它行星可能会影响地球
So, the idea that those planets could have any influence on us
人类的想法似乎有些异想天开
here on Earth seems fanciful.
事实上 如果你说的是
And, indeed, if you're talking about
遇到陌生帅哥的几率
your chances of meeting a handsome stranger
或者需要在周三时调整未来一周的生活安排
or your life plans requiring a moderate reconfiguration
那确实不会有影响
about a week on Wednesday, then you would be right.
但是如果要涉及到更深刻 更深层次的问题
However, if you ask more profound questions, deeper questions like,
比如地球为什么是这样
"Why is the Earth the way that it is?
地球上为何存在生命
"Why is there life on Earth?
人类为何存在
"Why do we exist at all?"
那么事实证明这些行星 特别是木星
then it turns out that the planets, and Jupiter in particular,
对地球具有深远影响
have had a profound effect.
在生命初期 年轻的木星就开始横冲直撞
Early in its life, the young Jupiter went on the rampage.
这颗气态巨行星开始了穿越太阳系的
The giant planet embarked on a voyage of destruction
毁灭之旅
across the solar system...
它改写了太阳系各大行星的命运
..that transformed the destiny of the planets,
改变了地球上的生命历程
and the course of life on Earth.
木星是太阳系的守护者
Jupiter is the godfather of the planets.
对木星的探测研究有助于我们了解整个太阳系的形成
Understand it and you understand how the solar system came to be.
教父 木星
在地球上 我们能够一瞥木星的巨大威力
On Earth, we can see glimpses of Jupiter's power...
这些就是它在地球表面
..in the scars it's left...
留下的伤疤
..on the face of the planet.
这是美国亚利桑那州的巴林杰陨石坑
This is the famous Barringer Meteor Crater in Arizona.
它的直径大约是1000米
It is about a kilometre across,
从火山口边缘到底部深170米
170 metres from the rim to the crater floor
大约5万年前
and it was created about 50,000 years ago
一颗直径50米的陨石以每秒13公里的速度
when a meteorite, 50 metres across, entered the Earth's atmosphere
撞入地球大气层
travelling at about 13km per second.
这就意味着它从进入地球大气层
That means it would have taken around, what, seven seconds
到落地的时间大约需要7秒钟
to go from the top of the atmosphere to the ground
它撞击地球的力度很大 释放出的能量相当于
and it hit with such force that the energy released
1000万吨♥炸♥药♥爆♥炸♥的当量
was equivalent to ten megatons of TNT.
它就像一枚巨大的核弹
And that is a very large nuclear bomb.
科学界认为
The meteorite that hit the Earth here
这颗撞击地球的陨石来自小行星带
is thought to have come from the asteroid belt...
就是围绕内太阳系边缘
..the ring of rocky debris that orbits at the edge
运行的岩石残骸环带
of the inner solar system.
它很可能是在木星
And it was deflected from its orbit
引力的作用下偏离了运行轨道
most likely by the gravitational influence of Jupiter.
木星与地球是截然不同的两类行星
Jupiter is a completely different class of planet to the Earth.
它是气态巨行星
A gas giant.
一个由氢和氦组成的巨大旋涡 它的体积巨大
A swirling ball of hydrogen and helium so large
足以容纳1300个地球
you could fit 1,300 Earths inside.
木星能够对小行星产生巨大的影响
Jupiter can exert such a powerful influence on the asteroids
因为它的质量大得惊人
because it's so massive.
大约是太阳系中其它所有行星
It's about two-and-a-half times the mass of all the other planets,
卫星和小行星总质量的2.5倍
moons and asteroids in the solar system combined.
所以它能够产生巨大的引力
And, therefore, it has a strong gravitational pull.
也就是说
And this means that Jupiter exerts an influence
木星对整个太阳系的影响之大 是仅次于太阳的
across the entire solar system that's second only to the sun.
这种影响不只是制♥造♥出像这样奇怪的陨石坑
And that influenced us far more than create the odd crater.
它还能够改变行星的历史
It can change the history of worlds.
要了解木星的重要地位
To understand how Jupiter rose to such dominance,
我们必须回溯历史 甚至是太阳系诞生之前
you have to go back to a time before the solar system even existed.
50亿年前
近50亿年前
Nearly five billion years ago,
一颗遥远的恒星爆♥炸♥ 在整个银河系掀起一股强烈的冲击波
a distant exploding star sent a shock wave across the galaxy...
结果导致形成太阳系的
..causing the cloud of gas and dust
气体和尘埃云大量坍缩
that would become our solar system to collapse...
太阳由此开始形成
..as the sun began to form.
但是在更远处 也有其它气体在逐渐聚集
But further out, something else was growing.
大约5000万年后
After 50 million years...
太阳的核熔炉燃起熊熊烈火
..the sun's nuclear furnace ignited.
当第一束阳光洒落时
The light of its first dawn...
太阳系的第一颗行星
..revealing Jupiter...
木星赫然呈现在眼前
..the solar system's first world.
这颗行星诞生得很早 吸收了太阳形成过程中
A planet born so early, it swept up most of the material
留下的大部分残骸
left over from the formation of the sun.
木星凭借其优势地位 对新形成的太阳系
Because of its dominance, Jupiter had a profound effect
产生了深远影响
on the newly forming solar system
并为我们地球的诞生铺平了道路
and paved the way for our living world to form.
这是我们太阳系的模型
This is a model of our solar system.
这是太阳 然后是4个内太阳系的岩石行星
So, here's the sun, and then we have the four inner rocky planets,
包括水星 金星 地球和火星
Mercury, Venus, Earth and Mars.
接着是小行星带
Then comes the asteroid belt,
一个围绕太阳运行的 由数百万颗小块岩石
the ring of millions of smaller pieces of rock
组成的环带
orbiting around the sun.
然后是气态巨行星
And then the gas giants.
包括木星 土星 天王星和海王星
Jupiter, Saturn, Uranus and Neptune.
现在它有了一个令人满意的规则结构
Now, this has a pleasing regular structure about it.
所有岩石行星靠近太阳
All the rocky planets close to the star
气态巨行星则相距甚远
and the gas giants further out.
我们认为这应该是行星形成的自然规律
And we thought that this must be the natural order of things,
太阳系的布局上就应是这样的
the way that solar systems have to form,
可是在探测遥远恒星周围的行星后
until we started to detect planets around distant stars
我们才发现这根本不是典型的布局
and then we found that this arrangement is not typical at all.
银河系有大约3000亿颗恒星 太阳只是其中之一
Our sun is just one of around 300 billion stars in our galaxy...
几乎每颗恒星
..and almost every one of those stars
都有自己的行星系统
is home to its own system of planets.
在其它大多数行星系统中 我们地球的公转区域是一片空旷的空间
In most other systems, the region where our planet orbits is empty.
而在更靠近恒星的地方 出现了许多“超级地球”
Instead, closer to the star, we see super-Earths,
行星：波江座40B 星座：波江座 质量：8.5个地球
是比太阳系的地球更大的类地行星
vast rocky planets many times bigger than our own.
但关键在于 这些行星据估计
But, crucially, these worlds are thought
覆盖着厚厚的有毒大气
to have thick toxic atmospheres,
行星：詹森 星座：巨蟹座 大气：氢和氦
因此根本不适宜生命存在
making them completely inhospitable to life.
这就提出了一个很有意思的问题
And that raises a very interesting question.
为什么我们的太阳系是这种布局呢
Why, then, is our solar system the way that it is?
为了寻找答案
To answer that question,
我们向太阳系的所有行星都发射了探测器
we've sent spacecraft to every one of the planets...
它们已经发现的各种异常现象
..and they've uncovered strange anomalies
揭示了我们太阳系久远的历史
that reveal our solar system's past.
金星探测器揭示 它曾经拥有的水量远远超出了
Our missions to Venus found that it once had far more water
我们对这颗近日行星的预期
than you'd expect for a planet so close to the sun...
它曾经可以匹敌地球
..just as Earth does today.
当探测器在火星降落时
The spacecraft we've sent to Mars
眼前的世界令人♥大♥吃一惊 它的大小只有姊妹行星
touched down on a world that is curiously just half the size
地球和金星的一半大
of her sister planets Earth and Venus.
在小行星带
And in the asteroid belt,
我们发现这里是许多消亡世界的墓地