了解宇宙是如何运行的（2010）

How the Universe Works S06E02

Part 3 Dec. 22, 2021, 7:22 p.m.

太阳系是在一个由气体和尘埃组成的圆盘形成的
The solar system formed out of a disc of gas and dust,
当木星形成时
and as Jupiter formed,
它会穿过这些物质
it would've been plowing through this material.
而当它穿过这些物质时
And if it plows through that material,
它就会受到阻力，动能降低
it's experiencing drag.
于是太阳的引力战胜木星的离心力
As it was losing energy, it would start to move in
木星就会开始相对缓慢地向太阳移♥动♥
toward the Sun relatively slowly.
谷神星形成于太阳系的外缘
Ceres formed in the outer edges of the solar system.
它从柯伊伯带中脱离出来
It was dislodged from the Kuiper belt
并因为木星的移♥动♥而向内拉
and yanked inwards by the migration of Jupiter,
当木星停止移♥动♥时，谷神星也停止了移♥动♥
and when Jupiter stopped migrating, so did Ceres.
然后在小行星带上进入了一个新的稳定轨道
It settled into a new, stable orbit in the asteroid belt.
一旦你意识到
Once you realize
这样奇怪和戏剧性的事情可能会发生
that something that strange and dramatic can happen,
一颗矮行星可能在太阳系的很远的地方形成
that a dwarf planet can form far out in the solar system
然后被拖到了太阳系内侧
and be brought in,
你一定会思考这种事情以前发生过多少次
it makes you wonder how many times that happened before.
会不会有其他几代矮行星
Could there have been other generations of dwarf planets
被抛向太阳
that got thrown in towards the Sun
或者完全被抛出太阳系？
or maybe were thrown out of the solar system entirely?
科学家认为
Scientists believe that squadrons of rocks
曾经有数以百计的由岩石和冰块构成的矮行星
and icy dwarf planets
组成一支中队
may have hurdled into the solar system.
呼啸着进入太阳系内部
Hundreds set out.
但只有一个幸存了下来
Only one survived.
如果外太阳系中
If there was a population
有一群小矮星向内迁移
of small dwarf planets
谷神星可能是唯一的幸存者
in the outer solar system that migrated inwards,
硕果仅存的一颗
Ceres might be the sole survivor, the only one left.
所以如果谷神星
So if Ceres settled into its new home
在小行星带的新家安顿下来
in the asteroid belt,
那其他的冰世界矮行星在哪里？
where are the rest of the icy worlds and the water on them?
谷神星可能是从太阳系外♥围♥迁移来的
The idea that Ceres may have moved in
这个想法很有趣
from the outer solar system is interesting,
但是为什么这个理论对我们来说很重要呢？
but why should it be important to you?
难以置信的是
And incredibly, the answer might be inside your own body
答案可能就在你自己的身体里
right now.
很长一段时间以来，我们一直在想
For the longest time, we've wondered
地球上大部分的水是从哪里来的？
where did the majority of earth's water come from?
你知道地球在哪里？
When you think about where the earth is,
它离太阳有多近
how close it is to the Sun,
这里就不应该有水的存在
there shouldn't have been any water here.
了解谷神星的演化
Understanding the evolution of Ceres,
从它形成的地方到我们今天发现它的地方
from where it formed to where we find it today,
也可以引导我们了解
could also lead us to understand how the earth can end up
地球如何最终拥有比我们预期的更多的水
with more water than we would otherwise expect.
在地球形成的过程中
When the earth formed,
由于太热
it was too hot for water to exist on the surface.
水无法在地表上存在
Perhaps the squadrons of dwarf planets
在这些矮行星的旅程中被打碎了
broke up on their journey,
用富含水的岩石向地球倾泻
showering earth with water-rich lumps of rock,
这些岩石中的水足以填满地球的海洋
enough to fill earth's oceans.
令人惊讶的是，当我们研究水的化学成分时
Amazingly, when we study the chemistry of water,
最能够匹配是你体内的水是
the best match is that the water in your body right now
来自于小行星本身
came from asteroids themselves,
小行星或矮行星它们在数十亿年的时间里
asteroids and dwarf planets that rained down
不断地降落并撞击地球
and hit the earth over billions of years.
矮行星可能还带来了一些其他的东西
Dwarf planets may have brought something else.
2017年2月
February 2017, scientists announce
科学家宣布在谷神星表面
the discovery of organic materials
发现了有机物质
on the surface of Ceres.
在地球上
On earth, life uses water
生命所需要的水和有机化合物碳基分子
and organic chemistry, carbon-based molecules.
矮行星的有趣之处在于
The intriguing thing about the dwarf planets
它们同时拥有这两种物质
is that they have both of those.
冥王星和谷神星都存在有机分子
Pluto and Ceres have organic molecules.
地表下也都存在液态水
There's liquid water below the surface.
有一种能源可以使星球内部暖和起来
There's a source of energy that warms the interior.
在这些冰冷的地表之下
It is not at all impossible that somewhere under
有生命存在并非完全不可能
these cold, icy surfaces, there could be life.
其他矮行星也有生命吗？
Could other dwarf planets host life, too?
塞德娜和鸟神星都有红色的斑块
Sedna and makemake both have red-colored patches.
这种颜色来自一种叫做索林（tholins）的有机分子
The color comes from something called tholins,
而它可能就是生命的起源
organic molecules that could be a precursor to life.
从这些有趣的
Based on all the interesting chemistry they're doing,
化学现象来看
these dwarf planets could be like
这些矮行星就像是太阳系的试管
the test tubes of the solar system.
如果太阳系里到处都是这样的小天体
If there are small bodies strewn all about the solar system
它们有液态水或冰
that had liquid water or ice,
那么它们就有可能成为生命的孵化器
it could possibly serve as an Incubator for life,
只要附着在小天体上
just holding on to it,
随时准备撞向另一个天体，并在那里播种
ready to crash into another body and seed it.
这就意味着
The habitable zone now extends
宜居带已经延伸到了整个太阳系
to the entire solar system.
这个的确是非常大地、非常大地扩张了宜居带
It really expands... It greatly expands...
生命有可能在整个星系的区域存在
The stage for the play of life in the entire galaxy.
也许我们的存在
Maybe we have dwarf planets to thank
应该感谢矮行星的存在
for our very existence.
突然之间，太阳系中最小的天体
All of a sudden, the smallest bodies in our solar system
变成了我们所见过的
have become some of the most interesting things
最有趣的东西
we've ever seen.
矮行星会迁移的想法
The idea of migrating dwarf planets
打开了另一些有趣的设想
opens up some intriguing scenarios,
其中还包括了另一个可能的事实
including one really out-there possibility.
有一些水和有机物质
Some of that water and organic material
可能不是来自我们的太阳系
may not be from our solar system.
我们对矮行星了解得越多
The more we learn about dwarf planets,
它们就越让我们吃惊
the more they surprise us.
有一颗矮行星的存在
But there's one dwarf planet
依然还是一个不解的谜
whose very existence is a mystery.
它就是赛德娜,没有人确切知道
It's called Sedna, and no one is quite sure
它在我们的太阳系中起什么作用
what it's doing in our solar system.
塞德娜可能是整个太阳系中
Sedna may have my vote for the single most peculiar object
最奇特的天体
in the entire solar system.
这个大约有1000英里（约1600多公里）宽的世界
Here, we have a world which is about 1,000 miles wide,
但它在太阳系中的轨道距离远远超过了海王星的轨道
but it is way far out in the solar system, way past Neptune.
塞德娜是我们在太阳系中
Sedna is the most distant object
发现的最远的天体
we've identified in our solar system.
站在塞德娜的表面
Standing on the surface of Sedna,
回望太阳系
looking back at the solar system,
太阳看起来会像一颗非常明亮的恒星
the Sun would look like a really bright star,
但不会比一颗真正明亮的恒星亮多少
but not much more than a really bright star.
和冥王星一样
Just like Pluto,
塞德娜也有一个奇怪的椭圆形轨道
Sedna has a strange, elliptical orbit.
不同之处在于，塞德娜距离太阳的距离
The difference is, Sedna travels from 7 billion
从70亿英里到930亿英里不等（大约113公里到1500公里）
to 93 billion miles from the Sun,
与冥王星不同的是
and unlike Pluto, its orbit can't be explained
它的轨道无法用靠近海王星的距离来解释
by its close proximity to Neptune.
赛德娜的奇怪之处在于它的轨道
The weird thing about Sedna is its orbit.
当它离任何一颗主行星的距离都那么远的时候
How could it have gotten that elliptical
它怎么会变成椭圆呢？
when it's that far away from any of the major planets?
如果有一个离海王星足够近的天体
If you have an object that's close enough to Neptune,
海王星的引力会影响它的轨道
Neptune's gravity can affect its orbit
并使它进入椭圆轨道
and swing it into an elliptical orbit.
问题是，塞德娜永远不会离海王星那么近
The problem is, Sedna never gets that close to Neptune.
它离那个轨道很远
It doesn't get anywhere near close enough
这就意味着
to be in that kind of orbit,
一定发生了别的事情
and that means that something else is going on out there.
塞德娜不能用我们知道的一些理论来解释
Sedna cannot be explained using objects that we know.
而太阳系其他的一切天体
Everything else, we can understand