了解宇宙是如何运行的（2010）

How the Universe Works S08E03

Part 5 Jan. 30, 2022, 2:58 p.m.

That's over 160,000 miles
an hour.
泰勒:那么，以我们目前的技术
Thaller:
So with our current technology,
我们有机会真正看到
do we have any chance
of actually seeing
其他行星的样子吗？
what these other planets
are like?
那么，想想我们目前拥有的
Well, think about the fastest
and farthest things
最快和最远的东西，比如旅行者号♥宇宙飞船
we have right now,
like the voyager spacecraft.
它们已经在太空中旅行了30多年
They've been in space
for more than 30 years
以惊人的速度飞行——每小时38000英里（约61200公里）
going incredibly fast --
38,000 miles an hour.
3万8千英里（约61200公里）的时速是很快的
Narrator:
38,000 miles an hour is fast.
但离我们最近的星系
But the closest galaxies to us
正在以四倍于这个速度向外移♥动♥
are moving away at over
four times that speed.
探测器被送到的地方越远
And the further away a probe
is sent to travel,
任务就越艰巨
the tougher its task.
关于宇宙膨胀的一个问题是
The thing about the expansion
of the universe
物体离你越远
is that the farther away
something is,
它离开你的速度也越快
the faster it's moving
away from you.
两个物体距离越远，它们之间的空间就越大
The more distant two objects
are away from each other,
它们之间的空间越大
the more space there is
between them,
就有越多的空间
and the more space
there is between them,
可以扩展
the more space there is
to expand.
奥卢西伊:它们移♥动♥的速度
Oluseyi: The rate at which
they're moving away
与它们的距离成正比
is proportional
to their distance.
如果距离是两倍，它就以两倍的速度移♥动♥
If it's twice as far away,
it moves away twice as fast.
距离地球三倍远
It is three times farther away,
移♥动♥的速度也是三倍快
and moves away
three times as fast.
把它放大到我们在38亿光年之外
Narrator: Scale it up to
the planets we've discovered
发现的行星
3.8 billion light-years away,
“感谢”宇宙的膨胀
and thanks to the expansion
of the universe,
那些星系外的世界也正在以
those extra-galactic worlds
are moving away from us
每秒49000英里（约78900公里）的速度远离我们
at over 49,000 miles per second.
想像一下，你是一名跑步者，你看到了终点线
Imagine that you're a runner,
and you see the finish line.
你离它越来越近了
You're getting
a bit closer to it,
但是现在，实际上，赛道本身在扩张
but now, actually,
the track itself is expanding.
随着赛道扩张的速度越来越快
And as the track expands
faster and faster,
它的扩张速度超过了你的极限
it's expanding faster
than you can possibly run.
突然之间，终点线开始后退
All of a sudden, that
finish line starts receding,
而你永远都无法到达终点
and you're never, ever
gonna reach it.
假设有一天我们能够建造一个探测器
Narrator: Say one day
we're able to build probes
以物理学所允许的最快速度飞行
that travel at the fastest speed
physics allows --
也就是光速
the speed of light.
即使这样也可能不够
Even that might not be enough
因为有时候宇宙本身
because sometimes
the universe itself
并不遵守规则
doesn't play by the rules.
物体在太空中以超光速进行传播
It's not possible for things
to travel through space
是不可能的，但是空间
faster than the speed of light,
but it is possible for space
以超光速进行扩张却是可能的
to expand faster
than the speed of light.
特朗布莱:我们看的每一个地方
Tremblay: Everywhere we look,
we see very distant galaxies
我们都能看到非常遥远的星系它们明显在以
that are apparently receding,
or moving away from earth,
大于光速的速度远离地球
at greater than
the speed of light.
布洛克:我们可以在天空中看到遥远的星系
Bullock:
There are distant galaxies
we can see in the sky that,
即使我们建造最先进的宇宙飞船
even if we were to build the
most advanced spaceship possible
甚至能以光速飞行
that could even move
at the speed of light,
我们也永远无法到达那里
we could never get there.
我们在遥远的天空中看到的星系中
97% of the galaxies that we can
see in the distant sky
有97%是我们无法到达的
are actually unreachable to us.
所以对于所有的星系
Narrator: So for all
the galaxies out there
和所有可以孕育生命的行星来说
and all the planets
that could harbor life,
大多数都是我们无法触及的
most of them
are out of our reach.
宇宙物理学对第一次接触
The physics of the universe
has dealt an immense blow
造成了巨大的打击
to first contact.
宇宙的真♥相♥将永远对我们隐藏
The true reality of the universe
will always be hidden from us
因为这个，因为这个膨胀
because of this,
because of this expansion.
我们越是看宇宙的外面
Narrator: The further we look
out into the universe,
第一次接触就越不可能
the more unlikely
first contact becomes.
我们可能需要一个先进的
We might need
an advanced alien race
外星种族来拜访我们
to come and visit us instead.
假设我们很幸运
Suppose we get that lucky.
即便如此，第一次接触真的可行吗？
Even then, would first contact
actually be feasible?
奥卢西:我们认为外星人和我们一样
Oluseyi:
We think aliens are like us.
他们也不行
They're not.
我们假设生命和我们一样
We're assuming that
the life is like us
他们的行星环境也和我们一样
and that their planetary
environment is like ours.
我不认为宇宙中的大多数生命
I don't think
that's gonna be the case
都是这样的
for most of the life
in the universe.
那么，外星人能够在与我们
Narrator:
So, could extraterrestrials
和我们的星球的第一次接触中存活下来吗？
even survive first contact
with us and our planet?
[爆♥炸♥]
[ explosion ]
2019年7月——
narrator: July 2019 --
测试卫星发现了一个距离我们
the test satellite
discovered a new alien world
31光年的新的外星世界
31 light-years from us
名为 gj 357 d
named gj 357 d.
它的质量是地球的六倍多
At over six times the mass
of our home planet,
被认为是一个超级地球
it's thought to be
a super earth.
根据我们的观察
And from our observations,
超级地球似乎是最好的生命家园
super earths appear to be
prime real estate.
我们所看到的是最常见的
What we see is that
the most common type
类地行星类型是我们所说的超级地球
of terrestrial planet
is what we call a super earth.
所以这意味着它是一颗类地行星
So that means
it's a terrestrial planet,
但质量要大得多
but much more massive.
更大的质量意味着更大的重力
Narrator: More massive can mean
more gravity,
创造了一个完全不同于我们的行星环境
creating a planetary environment
completely unlike our own
和完全不同于我们的生命
and life completely unlike ours.
奥卢西:如果他们在一个超级地球的表面
Oluseyi: If they're on
the surface of a super earth,
那么重力可能会更强
it could be that gravity