了解宇宙是如何运行的（2010）

How the Universe Works S08E03

Part 8 Jan. 30, 2022, 2:58 p.m.

But how about a drink?
我们所知道的生命的存在
In order for life as we know it
to exist,
都需要液态水
one needs liquid water.
如果外星人生活在一个贫瘠的沙漠星球上
Narrator: If aliens live
on a barren desert planet,
像我们这样的水世界可能非常有吸引力
a water world like ours
could be highly attractive.
虽然我们称自己为蓝色星球
While we call ourselves
the blue planet,
但我们的海洋并非独一无二
our oceans are not unique.
宇宙提供了更多的水资源
The universe offers
far greater water resources.
萨特:在我们的太阳系中，我们发现
Sutter: In our solar system,
we're finding that
大部分液态水存在于气体巨星周围的卫星中
most of the liquid water exists
in moons around the gas giants.
我们相信木星的卫星木卫二
Narrator: We believe
jupiter's moon europa
有一层大约15英里（约24公里）厚的水冰
has a layer of water ice
around 15 miles thick
漂浮在100英里（约161公里）深的海洋上
floating on an ocean
up to 100 miles deep.
这颗卫星所含的水可能是地球上
This single moon may have
twice as much water
所有海洋总和的两倍
as all earth's oceans combined.
木卫二是我们太阳系的水世界
Europa is the water world
of our solar system
而不是地球
and not the earth.
所以，如果你是一个寻找水的外星人
So if you were an alien
looking for water,
你不会费事去找像地球这样的大行星
you wouldn't bother going to
a big planet like the earth
然后通过某种巨大的吸管把水吸进走
to suck it up through
some kind of giant straw.
你会去外太阳系
You'd go to
the outer solar system.
你可能会收获冰冷的卫星
You might harvest icy moons.
与其对抗
Narrator:
Instead of working against
地球强大的引力
the powerful gravitational pull
of earth,
外星种族可以从木卫二取水
an alien race could draw water
from europa,
那里的引力比地球弱十倍
where gravity is almost
10 times weaker.
那么我们还能提供什么资源呢？
So what other resources
have we got to offer?
也许外星人是来开采地壳上的
Maybe aliens come to strip mine
the earth's crust
金属——比如铁、钛或铂
for metals -- iron or titanium
or platinum.
外星人可能会用这些金属
Aliens might use these metals
做和我们完全一样的事情——
for exactly the same things
that we do --
建造宇宙飞船，建造他们的技术
for building spaceships,
for building their technology.
这些材料对于任何
Narrator:
Such materials could be useful
缺乏矿产资源的外星文明来说都是有用的
for any alien civilization
short on mineral resources.
问题是，我们星球上的很多金属
Problem is,
a lot of our planet's metals
都深埋在地球内部
are buried deep
in the earth's interior.
地球形成时，大量的铁
When the earth formed,
the great deal of its iron
沉入地球的核心
sunk down into the core
of our planet
并带走了大量的金属
and took a lot of metals
with it.
所以它们在地球上很难开采
So they're actually quite hard
to mine on the earth.
一个外星种族在小行星带寻找
Narrator: An alien race would be
better off prospecting
会更容易获得的矿物资源
for more accessible minerals
situated in the asteroid belt.
在小行星带中，有一颗叫做普赛克的小行星
In the asteroid belt, there's
an asteroid called psyche,
它由纯铁镍组成
which is made up
of pure iron nickel,
就像地心一样
just like the core of the earth.
普赛克提供了一个近150英里（约242公里）长的
Narrator: Psyche provides
a near-150-mile
裸♥露♥的铁镍带
exposed strip of iron nickel,
这是另一个外量人不需要麻烦我们的原因
yet another reason e.T.
Wouldn't need to bother with us.
在我看来，这些原因
For my money,
none of those reasons
都不会吸引外星人来地球
would draw aliens to earth.
所有这些东西在其他地方都很容易找到
All these things can be found
far more easily elsewhere.
第一次接触的可能性
Narrator: The possibility
of first contact
听起来越来越遥远
is beginning to sound
increasingly remote.
宇宙设置了巨大的障碍
The universe throws up
massive barriers
阻止我们与有智慧的外星种族交流
stopping us from communicating
with an intelligent alien race,
而这个种族很可能完全没有兴趣
a race that might very well
have absolutely no interest
与我们联♥系♥
in contacting us,
除非，当然，他们已经有兴趣了
unless, of course,
they already have.
有没有可能我们已经探测到外星人的信♥号♥♥
Is it possible that
there have been alien signals
但我们没有意识到它们是什么？
that we've already detected but
we didn't realize what they are?
科学家们发现了一个
Narrator:
Scientists have discovered
他们无法解释的强大的宇宙信♥号♥♥
a powerful cosmic signal
that they cannot explain.
这最终会成为第一次接触吗？
Could this finally be
first contact?
[爆♥炸♥]
[ explosion ]
2018年7月——
narrator: July 2018 --
不列颠哥伦比亚省的齐姆望远镜
the chime telescope
in british columbia
探测到一股比眨眼还要快的
detected a short flash
of radio energy
射电短闪
quicker than a blinking eye.
它被称为快速无线电暴
It's called a fast radio burst.
这些都是非常强大的，非常非常短
These are intensely powerful,
very, very short
的无线电脉冲，在射电波长上
lived radio bursts
that can be 1,000 times brighter
比太阳亮1000倍
than the sun
at radio wavelengths,
瞬间到达并消失
that arrive and disappear
in an instant.
大多数快速无线电脉冲都是一次性的
Narrator: Most fast radio bursts
are one-offs,
一闪而过，然后就永远消失了
blinking into existence,
then disappearing forever.
但这个不是
But not this one.
几天后，科学家们再次捕捉到了闪光
A few days later, scientists
caught the flash again.
产生这样的爆发所需要的能量
The amount of energy
that it takes to produce
对于我们在地球上
a burst like this,
从数十亿光年外
for us to detect it
here on earth
探测到它，是极其巨大的
from billions of light-years,
is immense.
我们以前也遇到过类似的事情——
And we've run across
things like this before --
爆♥炸♥的恒星，伽马射线爆发
exploding stars,
gamma-ray bursts.
这些都是非常奇怪的物体
These are all
very strange objects,
但这无法解释这个现象
but that does not explain these
因为一些快速的无线电脉冲会重复
because some of these
fast radio bursts repeat.
所以不管是什么能产生这种能量
So whatever it is that can
generate this kind of energy,
它都能产生不止一次
it can do it more than once.
光有很多不同的波长
Narrator: Light comes in
many different wavelengths.
无线电波是最长的，因此很适合
Radio waves are the longest,
making them good
远距离通信
for long-distance communication.
我们使用无线电波已有100多年的历史
We've used radio waves
for over 100 years,
从无线收音机到电视
from wireless radio to tv,
从手♥机♥通话到用太空探测器
from cellphone calls
to communications