宇宙时空之旅（2014）

Cosmos: A SpaceTime Odyssey S01E11

Part 4 April 25, 2021, 12:41 p.m.

如果这些星球存在着
If any of these worlds are home
拥有射电望远镜的文明
to a civilization with radio telescopes,
他们可能已经知道人类在地球了
they could already know that we're here.
如果其他星球也在把自己的故事
What if other worlds are sending
发送到太空中那会怎样
their stories into space?
自1960年以来我们一直在监听
Since 1960, we've been listening
来自地球外的无线电♥信♥♥号♥♥
for extraterrestrial radio signals
却并未听到类似钟声的声音
without hearing so much as a tolling bell.
但是我们的研究还太零散
But our search has been sporadic
只拘泥于宇宙中的特定部分
and limited to certain parts of the sky.
如我们所知
For all we know,
我们也许刚刚错过了外星人的信♥号♥♥
we may have just missed an alien signal,
因为在错误的时间
looking in the wrong place
找错了地方
at the wrong time.
我们只监听了的银河系中
We've only listened to a miniscule fraction
一小部分恒星
of the stars in our galaxy.
也许还有其他问题
And there may be another problem...
从某种程度上来说
we are, to some extent,
我们人类是时间的囚徒
prisoners of our own moment in time
并且受到科学技术的限制
and the limits of our technology.
无线电与电视广播
Radio and television broadcasting
在人类的技术发展历程中
may be only a brief passing phase
也许只是昙花一现
in our technological development.
当我们在想象外星文明
When we imagine alien civilizations
通过射电望远镜发射无线电♥信♥♥号♥♥时
broadcasting signals with radio telescopes,
我们又与那些幻想着
are we any different from earlier generations
坐炮弹飞到月球的先人们有何区别呢
who imagined riding cannon shells to the Moon?
比人类更先进点的外星文明
Civilizations even slightly more advanced than ours
也许已经改用
may have already moved on
另一种通讯方式了
to some other mode of communication,
一种我们还未发现
one that we have yet to discover
更无法想象的方式了
or even imagine.
他们的信息也许
Their messages could be
此时此刻就围绕在我们周围
swirling around us, at this very moment,
但是我们没有方法来获取这些信息
but we lack the means to perceive them,
就像我们的祖先
just as all of our ancestors,
在一个多世纪前一样
up to a little more than a century ago,
也会无视从其他地方传来的
would have been oblivious to the most urgent radio signal
紧急无线电♥信♥♥号♥♥
from another world.
还有一个更棘手的可能性
But there's another, more troubling possibility--
外星文明就像生物一样
civilizations, like other living things,
都会由于自然原因或暴♥力♥
may only live so long before perishing
或是自己造成的破坏
due to natural causes, or violence,
在存在一段时间后消亡
or self-inflicted wounds.
我们是否能够接触到
Whether or not we ever make contact
外星智慧生命
with intelligent alien life
也许取决于另一个重要的问题
may depend on a critical question.
一个文明的寿命是多久
What is the life expectancy of a civilization?
在恩黑杜安娜时代
By the time of Enheduanna,
她第一次在作品上留下了作者名字
the first person to ever get a writing credit,
文明已经出现1000多年了
civilization was already more than 1,000 years old.
但如今她的繁华之城已是不毛之地
But today, her glorious city is a barren wasteland.
是什么原因
What went wrong?
其中一个原因是美索不达米亚平原上
One problem was the almost ceaseless warfare
城邦之间的近乎无休止的战乱
between the cities of Mesopotamia,
屡次摧毁他们的文明成就
which continually destroyed their achievements.
人们颂扬的伟大军功
They glorified military conquest
最终成为了自身的牺牲品
and ultimately became its victims.
另一个原因是
Another cause of decline
他们的技术知识
was that their technical know-how
已远超他们对于自然的理解
overran their understanding of nature.
设计精巧的灌溉系统
The ingenious irrigation system
这是伟大的美索不达米亚文明的基石
that was the basis for the great civilizations of Mesopotamia
但却造成了意想不到的后果
had an unintended consequence--
每年水都会经灌溉系统流入农田
the water channeled into their farmlands every year
水蒸发后盐分结晶
evaporated and left its salt behind.
经过一代又一代人的灌溉
Over generations, the salt accumulated
盐分的累积让庄稼枯死
and began to kill the crops.
大约在公元前2200年
And then, about 2,200 BC,
就在恩西杜拉娜时代之后不久
not long after the time of Enheduanna,
灾难降临
disaster struck...
极其严重的干旱
a drought of truly epic proportions,
持续了好几十年
lasting for many decades.
焦金流石草木萧疏
The rains stopped, crops withered,
饿殍遍野满目疮痍
and there was famine and anarchy.
后来蛮夷入侵
Barbarians invaded.
许多城邦的街道上到处都是死尸
The streets of many cities were littered with dead.
只有一种解释
There could be only one explanation.
至高无上的神恩利尔发怒了
Enlil, the supreme god, was angry
因为他的一座寺庙被毁了
because one of his temples had been destroyed.
美索不达米亚人也许不知道
The people of Mesopotamia could not know
同样的干旱吹灭了
that the same drought was crushing
埃及文明的曙光
the dawning civilizations of Egypt,
还有希腊印度
Greece, India,
巴基斯坦和中国
Pakistan and China.
地球上所有的神
All the gods of the Earth
一定是因为什么事而发怒了
must have been really angry about something.
尽管人们很聪明
For all their brilliance,
但那些文明中的人们
the people of those civilizations had no inkling
并不知道他们在经历气候突变
they were experiencing abrupt climate change.
3000年后气候也同样
3,000 years later, the climate
给另一个灿烂文明带来了突变
would change abruptly for another glorious civilization,
这次在中美洲
this one in Central America.
在它最巅峰的时候
At its peak,
玛雅文明消亡了
the Mayan civilization perished,
被持续了一世纪的一系列严重干旱
wiped out by a series of severe droughts
所毁灭
over the course of a century.
但这些文明与我们同在
We still carry within us
在我们语言和神话里的
the echoes of these extinct civilizations
那些灭绝文明依旧发出回响
in our languages and our myths.
如今人类进入了全球化文明的时代
Today, we have a single global civilization.
这次能持续多久
How long will it live?
文明灭绝的方式有很多种
There are so many ways for a civilization to die.
让我们从
Let's start with the ones
人类或许束手无策的情况开始
that we probably wouldn't be able to do much about.
1000光年外的超新星爆发了
That supernova is 1,000 light-years away.
如果再近一点比方说
If it were much closer, say...
距离地球小于30光年
less than 30 light-years from Earth,
爆发产生的宇宙射线
its cosmic radiation would shred
会打碎地球的大气臭氧保护层
the atmosphere's protective ozone layer
摧毁我们的文明
and destroy our civilization.
幸运的是起码在未来的几亿年里
Lucky for us, none of the stars close enough to harm us
距离近到能对地球造成伤害的恒星中
are likely to go supernova any time
没有一颗会超新星爆♥炸♥
in the next few hundred million years.
每隔一百万年左右
Every million years or so,
地球上会有超级火山爆发
a supervolcano erupts somewhere on Earth.
最近一次发生在七万四千年前的
The last time it happened was 74,000 years ago,
苏门答腊岛上
on the island of Sumatra,
也就是今天的印尼
in what is now Indonesia.
它喷出的
It spewed hundreds of times more
岩石火山灰和毒气
rock, ash and toxic gas
比有记载以来的任一火山爆发都超出百倍
than any single volcano in recorded history.
熔岩从地壳中喷发出来
The molten rock that erupted from Earth's crust
从火山口
left this caldera,
蔓延100千米
100 kilometers long,
现在这里成了一片湖
now filled with a lake.
多巴火山把超过2500立方千米的碎石
The Toba volcano sent more than 600 cubic miles
喷向了空中
of pulverized rock soaring skyward.
西风把火山灰带去了印度
The westward wind carried the volcanic ash over India,
火山灰就像一块厚毯子一样
where it fell out in a smothering blanket