了解宇宙是如何运行的（2010）

How the Universe Works S05E09

Part 5 April 18, 2021, 7:48 p.m.

families of icy moons swing around Jupiter
运行着很多冰质卫星家族
and saturn on elliptical orbits.
科学家们还发现了
And scientists have discovered icy exteriors
覆盖着广阔液态水海洋的冰层
that cover vast liquid water oceans.
正如我们在太阳系的卫星上所看到的
As we've seen in the moons in our solar system,
嗯，它们也可以非常活跃
uh, they can be very active.
如果它们是冰的
If they're icy, the gravitational interaction
它们与主行星的引力相互作用
with their host planet can stretch them
会拉伸它们、挤压它们、并使它们升温
and squeeze them and heat them up.
这些所谓的潮汐力
These so-called tidal forces could power hot
可以为火山口提供热的动力
volcanic vents just like the vents found
就像地球海洋深处的火山口一样
deep in the earth's oceans.
在我们的星球上
On our planet, ocean vents support
阳光照射不到的海洋火山喷口
all kinds of strange life
但那里依然支撑着各种奇怪的生命
without the benefit of sunlight.
类似的事情会发生在
Could something similar be happening
某个流浪星球的潮汐般炙热的卫星上吗？
on the tidally heated moon of a rogue planet?
这是完全有可能的
It's entirely possible, hugely speculative,
虽然很大程度上是推测性的
and let me be clear about that,
让我说得更明白点
but it's possible that you could have life
在一个没有太阳的星球上或许有可能有生命产生
arising on the moon of a sunless planet.
这些卫星
You could have these moons kind of snuggled up
依偎在这颗系外行星周围
around this exoplanet,
通过它的重力来保持温暖
keeping warm through its gravity.
所以即使周围没有恒星
So even with no star around,
仍然有生命存在的可能性
there's still possibility for life.
怪异的流浪行星
Weird rogue planets allow us
让我们开始梦想星际间的外星生命
to dream of interstellar alien life.
但是，很难想象
But it's hard to imagine these deep-sea creatures
这些深海生物
developing into advanced,
在火山口贫乏的能量下
complex, intelligent life
发展成先进、复杂、智能的生命
on the meager energy of volcanic vents.
要找到文明存在的证据
To find evidence of civilizations,
我们还是需要从别处寻找
we need to look elsewhere.
可能是一颗遥远恒星的
And it's just possible the weird behavior
怪异行为
of a distant star
为我们提供了
has provided our first clue
这些先进文明
that these advanced civilizations
可能真的存在的第一条线索
could really exist.
我们曾经认为
We used to think our galaxy
我们的星系里只有恒星
was only filled with stars.
现在我们知道这些恒星也有行星
We now know those stars have planets, too,
有数千亿颗
hundreds of billions of them.
天文学家称这些外星世界为系外行星
Astronomers call these alien worlds exoplanets.
之前我们甚至不知道有系外行星
（译者早就一直认为有系外行星存在，
只是发现不了，为什么这些科学家们
之前会不知道有系外行星？
——译者注）
WoWe didn't even know that there were exoplanets.
现在，想想在过去的10到15年里
（译者早就一直认为有系外行星存在，
只是发现不了，为什么这些科学家们
之前会不知道有系外行星？
——译者注）
And now, it's just mind-blowing
我们对我们的宇宙了解增加了多少
（译者早就一直认为有系外行星存在，
只是发现不了，为什么这些科学家们
之前会不知道有系外行星？
——译者注）
to think about how much we've learned about our universe
真是令人兴奋
（译者早就一直认为有系外行星存在，
只是发现不了，为什么这些科学家们
之前会不知道有系外行星？
——译者注）
just in the last, you know, 10 to 15 years.
这是我们对外界事物理解的
（译者早就一直认为有系外行星存在，
只是发现不了，为什么这些科学家们
之前会不知道有系外行星？
——译者注）
This is a really fundamental shift
一个根本性转变
（译者早就一直认为有系外行星存在，
只是发现不了，为什么这些科学家们
之前会不知道有系外行星？
——译者注）
in our understanding of what is out there.
自2009年以来
Since 2009,
执行对系外行星搜寻任务的
a planet-hunting space observatory
开普勒(kepler)太空望远镜
called kepler has revolutionized
让搜寻系外行星的工作发生了彻底的改变
the search for exoplanets,
它的探测到的系外行星数量
locating more than all
超过了地球上其他所有望远镜的总和
the telescopes on earth combined.
开普勒之所以成功
Kepler's success is due to its ability
是因为它能够同时观测15万颗恒星
to keep watch on 150,000 stars simultaneously.
如果开普勒发现其中一颗恒星
If kepler spots the light from one of those stars
发出的光在一瞬间变暗
dimming just for a moment,
那么一颗系外行星可能正在穿过它的轨道
an exoplanet could be crossing its path.
探测到的亮度变化幅度越大
And the greater the drop detected,
则系外行星的体积可能就越大
the bigger the exoplanet could be.
但在2011年和2013年
But in 2011 and 2013,
开普勒发现了一颗亮度变化
kepler spots dips in brightness
超出了正常范围的恒星
that are off the scale.
这颗神秘的恒星被称为“塔比之星”
The mystery star is dubbed tabby's star,
以研究这个奇怪行为的
named for the astronomer
天文学家的名字来命名的
who investigated its strange behavior.
这种行为迫使科学家们
And that behavior has forced scientists to consider
考虑一种完全改变宇宙的可能性
a completely universe-changing possibility.
泰比星真的很有趣
The tabby star is really interesting because we know
因为我们知道有一个物体绕它运行
there's an object that's orbiting it.
它挡住了大量的光线
And it's blocking a really large amount of the light.
所以我们才知道它在那里
That's how we know it's there.
但它比一般行星所能阻挡的要多得多
But it's much more than a planet typically would block.
如果你有一颗木星大小的行星围
If you have a Jupiter-sized planet
绕着一颗普通恒星运行
orbiting a normal star,
你会挡住百分之一的光线
you block a percent of the light.
这只是一个非常非常小的亮度下降
It's a very, very small dip.
但是对于塔比星，我们看到的是
But with tabby's star, what we're seeing are huge dips
巨大亮度下降幅度，有20%的光被遮挡住了
where 20 percent of the light is being blocked.
如果开普勒的读数是正确的
If kepler's readings are right,
一些巨大的东西正在塔比星周围移♥动♥
something huge is moving around tabby's star.
还有一个外部的可能性
And there's an outside chance
就是某个行星的残余物
that something is the remnants of a planet
被外星人拆开后
taken apart by aliens
制♥作♥成一个巨大的太阳能发电厂
and repurposed as a giant solar power plant.
真正先进的文明会做的
What really advanced societies
只是把一些毫无价值的星球
would do is just take apart some worthless planet,
比如我们太阳系里的海王星
like Neptune in our own solar system,
拆成一个巨大的球体
and rebuild it as a giant sphere
放在他们星球的轨道之外
outside the orbit of their planet,
收集并利用这些阳光
collect all that sunlight and then use that.
世界上最好的能源就是你的主星
WoThe best energy source anywhere is your star.
所以你可以建造巨大的建筑
So you might build giant structures
来获取能量
to actually harvest the energy.
弗里曼·戴森称之为戴森球
Freeman Dyson called this a Dyson sphere.
我们能找到一个戴森球吗？
Could we have found a Dyson sphere?
如果一颗系外行星的残骸
If the remains of an exoplanet
挡住了塔比星的光线
are blocking the light from tabby's star,
那么外星人肯定在忙碌着
the aliens have been busy.
它们的巨形结构一定非常巨大
Their megastructure would need to be vast to account
才能解释科学家所看到的暗淡现象
for the dimming seen by scientists.
戴森球也许是科幻小说的梦想
A Dyson sphere is the stuff of Sci-Fi dreams.
我们如何证明它是真实的呢？
But how can we prove it's real?
搜寻外星文明(SETI)的天文学家把望远镜转向塔比的恒星
Astronomers at SETI turn their telescopes to tabby's star
希望能窃听到外星人建造者的
in the hopes of eavesdropping on the radio chatter
无线电通讯
of its alien builders.
我们一听到塔比恒星的消息
As soon as we heard about tabby's star,
就把艾伦望远镜阵列的天线
we swung the antennas
朝着那颗恒星的方向摆动了
of our Allen telescope array in the direction of that star.
我们花了一两个星期的时间
And we spent about a week or two actually looking at it
通过无线电拨号♥的广泛范围来观察它
over a wide range of the radio dial,
寻找任何可能的信♥号♥♥ 但我们什么也没找到
looking for any signals. Well, we didn't find any.
在巴拿马，我们还用望远镜
We also used a telescope down in Panama
寻找闪光的激光
to look for flashing laser lights.
同样，我们什么也没有找到
We didn't find those either.
如果说一种戴森球