了解宇宙是如何运行的（2010）

How the Universe Works S09E02

Part 4 March 16, 2022, 8:54 a.m.

On Earth, there are
roughly 160 molecules of
160个重水分子比100万个普通水分子
heavy water for every million
molecules of normal water.
“罗塞塔”在彗星周围移♥动♥时
As Rosetta moved
around the comet,
测量了水蒸气中
it measured the ratio of
hydrogen to deuterium in
氢与氘的比例
the water vapor.
如果与地球的比例精确匹配
An exact match to Earth's
ratio would confirm that comets
将证实彗星是海洋的来源
were the source of our oceans,
但“罗塞塔”发现了一些令人惊讶的事情
but Rosetta discovered
something surprising.
“罗塞塔”发现的是，氘与氢的比例
What Rosetta found was that
the deuterium to hydrogen ratio
是地球海洋中水的三倍
was three times that of
the water in Earth's ocean.
这意味着像67P这样的彗星
That means a comet like 67P
不可能是地球水的来源
couldn't have been the source
of Earth's water.
谢里丹:如果这和海水的测量结果
SHERIDAN: If it was the same
as the measurement
是一样的
of the ocean water,
那么我们可以说这些彗星可能是
then we could have said that
these comets could have been
我们在地球上看到的水的输送机制
a delivery mechanism for
the water that we see on Earth.
事实上，它高出三倍，这表明
The fact it was three times
higher kind of indicates that
像67P这样的彗星
comets, like 67P,
并不是我们今天在地球上看到的水的来源
were not the source of the water
that we see on Earth today.
但是，尽管像67P这样的彗星没有给地球提供水
But although comets like
67P didn't deliver our water,
我们不能排除所有彗星
we can't rule out all comets.
奥卢西伊:我们必须正确看待这个问题
OLUSEYI: We have to keep
this in perspective.
67P只是一颗彗星，我们对彗星
67P is but one comet,
and what we know about
这类天体的了解是
objects like comets
它们是有一系列的，这些系列
is that they come in
families, and these families
有不同的组成成分
have different compositions.
所以可能有些彗星有类似地球的水
So it could be that some
have Earth-like water,
是它们把水带到地球上的
and those are the ones that
brought water to Earth,
而有些则没有
and some don't.
拜沃特斯:我不认为这样的结果会导致
BYWATERS: I don't see
wrinkles like this
地球上水的理论需要“重起炉灶”
as going back
to the drawing board.
当然，我们有时会得到更多的问题而不是答案
Sure, we get more questions
sometimes than answers,
但这让我们能够进一步探索，并真正扩展
but that allows us to probe
farther and really expand
我们对行星形成的知识
our knowledge into
how planets formed.
67P彗星的组成成分
The composition of Comet 67P
改写了我们对太阳系的理解
rewrites our understanding of
并且这颗彗星
the solar system, and the comet
有更多的秘密要揭示
has more secrets to reveal.
泰勒:我们之所以要一路追踪
THALLER: The reason we went
all the way
67P彗星
out to Comet 67P,
事实上，我们之所以研究彗星
and, in fact, the reason
we studied comets at all,
是因为我们在寻找生命起源的线索
is we're looking for clues
about the origins of life.
在“罗塞塔”探测器检查彗星的冰核时
As Rosetta examined
the icy core of the comet,
它发现了大量的分子
it found a treasure trove
of molecules.
67P能携带构成生命本身的元素吗？
Could 67P carry the building
blocks of life itself?
“罗塞塔”前往67P彗星的任务是
Rosetta's mission
to Comet 67P planned to answer
为了回答行星科学中最大的问题
the biggest questions
in planetary science,
而其中最大的问题莫过于
and none as bigger
than figuring out
弄清地球上生命的起源
the origins of life on Earth.
地球上的生命在地球冷却后
Life on Earth got started
not long after
不久就开始了，大约是45亿年前
our planet cooled, something
like 4.5 billion years ago.
但我们不知道确切的过程
But we don't know
the exact process.
所有这些生命都是从地球上的分子
Did all that stuff
come together here from
聚集在一起，然后变得越来越复杂的吗？
molecules on Earth and become
more and more complex?
还是生命是从太空带来的？
Or was it brought from space?
[爆♥炸♥]
[explosion blasts]
“罗塞塔”号♥开始寻找
Rosetta began to hunt for
构成生命的元素……基本有机化合物
the building blocks of life...
Basic organic compounds.
因此，我们一直认为彗星可能携带
So we always thought
that comets probably
有机物质，但在“罗塞塔”号♥之前
carry organic materials,
but we really couldn't
我们真的无法证实这一点
confirm that until Rosetta.
拉德堡:“罗塞塔”检测到了脂肪族化合物
RADEBAUGH:
It detected aliphatic compounds,
这是一种富含碳和氢的有机物
which are organics rich in
carbon and hydrogen, and that is
这是首次在彗星表面
the first time such a substance
检测到这种物质
has been detected at
the surface of a comet.
兰扎:这些材料是制♥造♥蛋白质的
LANZA: These materials
are the raw building blocks
原始材料
for making things like proteins,
而蛋白质是所有生命所必需的
which are required for all life.
这非常重要，因为这表明
This is really important,
because this says that
这些物质可能是由彗星送到地球的
possibly these materials were
delivered to Earth by comets.
彗星在整个太阳系中
The idea that comets
carried the building blocks for
携带着生命的基石的观点
life across the solar system
is known as
被称为分子生源说
molecular panspermia.
你可以把彗星想象成
You can kind of think of
comets is being like space
太空运输卡车，对吧？
delivery trucks, right?
它们正在外太空形成
They're forming out there
in deep space.
所有这些物质都是和它们一起形成的
All this stuff is being
formed with them,
然后它们把它们带到地球上
and then they bring it to Earth.
但现在，你懂的，你不希望
Now, you know,
you don't want your
送货卡车撞穿你的前门
delivery truck smashing
through your front door,
但在彗星的情况下，当它们撞击地球时
but in the case of comets,
when they impact the Earth,
它们可以把这些分子分散到各个地方
they can distribute those
molecules all over the place.
但在某种程度上，我们跳过了一个步骤，对吧？
But in some way, we're kind of
skipping a step, right?
我的意思是，彗星可能
I mean, so the comet
may be bringing
会把生命的成分带到地球
the ingredients of life
to the Earth,
但彗星从哪里得到这些成分的呢？
but where'd the comet get
those ingredients?
答案可能在太空深处
The answer may be in
deep space,
在恒星系统和星系之间
in the matter
and radiation floating
遭受辐射的漂浮物质
between star systems
and a galaxy.
被称为星际介质
It's called
the interstellar medium.
杜尔达:很有趣的结果是
DURDA:
The really interesting result
彗星67P的总体组成
is that the overall
composition of Comet 67P
和该彗星中一些真正有趣的成分
and some of the really
interesting ingredients
非常相似、相同
in that comet are very similar,
在某些情况下，我们在星际介质中
identical, in some cases,
two materials we find out there
发现了两种物质
in the interstellar medium,