评论
打印
Could human civilization eventually spread across the whole Milky Way galaxy?
人类文明最终能传播到整个银河系吗？
Could we move beyond our small blue planet to establish colonies in the multitude of star systems out there?
我们能在这个小小的蓝色星球之外的广袤星系建立殖民地吗？
This question's a pretty daunting one.
这个问题还挺吓人的。
There are around 300 billion stars in the galaxy, which is about 160,000 light-years across.
银河系有3000亿颗恒星左右，从一边到另一边的距离是160000光年。
So far we've sent a single spacecraft outside our solar system, trudging along at 0.006% of the speed of light.
现在为止我们就发送了一艘宇宙飞船到太阳系外，以0.006%光速缓慢前行。
At that rate, it would take over 2.5 billion years just to get from one end of the galaxy to the other.
以那个速度，得花不止25亿年才能横跨一个星系。
And then there's the question of human survival.
然后就有了这个人类生存的问题。
The gulf between stars is simply enormous.
恒星间的距离简直大无边际。
We couldn't live sustainably on most planets, and we require a lot of resources to stay alive.
在多数星球上我们都不能持续生存，而且我们需要很多资源才能存活下来。
And yet, decades ago, scholars found that it's theoretically possible to not just spread human civilization across the galaxy,
然而几十年前，学者发现从理论角度在银河系传播人类文明不仅是可行的，
but to do so quite quickly, without breaking any known laws of physics.
而且还能很快实现，还不违背现有的物理定律。
Their idea is based on the work of a mathematician named John von Neumann,
这个想法源于一名叫约翰·冯·诺依曼的数学家的研究，
who designed on paper machines that could self-replicate and create new generations of themselves.
他在纸上设计了一台能进行自动复制和创造新一代的机器。
These would later come to be known as von Neumann machines.
后来这些机器被称为冯·诺依曼机器。
In the context of space exploration, von Neumann machines could be built on Earth and launched into space.
在太空探索的背景下，冯·诺依曼机器可以建在地球上，然后发射进太空。
There, the self-sufficient machines would land on distant planets.
太空中，这种自给机器会在遥远的星球着陆。
They would then mine the available resources and harvest energy,
然后开采可用资源、搜集能量，
build replicas of themselves, launch those to the nearest planets, and continue the cycle.
进行自我复制，把复制的机器发射到最近的星球，然后不断循环这个过程。
The result is the creation of millions of probes spreading outwards into the universe like a drop of ink in a fishbowl.
最后结果就是无数探测器像水里的一点墨水一样不断向外在宇宙中蔓延。
Scholars crunched the numbers and found that a single von Neumann machine traveling at 5% of the speed of light
学者进行计算之后发现，一台冯·诺依曼机器以5%光速飞行，
should be able to replicate throughout our galaxy in 4 million years or less.
要花400万年才能通过不断复制穿越银河系。
That may sound like a long time, but when you consider that our universe is 14 billion years old,
听起来时间很长，但想到140亿岁高龄的宇宙，
on a cosmic scale, it's incredibly fast -- the equivalent of about 2.5 hours in an entire year.
从宇宙尺度看来已经非常快了，也就是一整年里的两个半小时。
Creating von Neumann machines would require a few technologies we don't have yet,
造一台冯·诺依曼机器需要几项目前没有的新技术，
including advanced artificial intelligence, miniaturization, and better propulsion systems.
包括先进的人工智能、微型化科技、更好的推进系统。
If we wanted to use them to spread actual humans throughout the galaxy, we would need yet another technological leap
如果想运用这些技术把人类送进银河系，我们还得需要另一项技术性飞跃，
the ability to artificially grow biological organisms and bodies using raw elements and genetic information.
通过原始元素和基因信息来人为造出生物有机体和生物机体。
Regardless, if in the last billion years an alien civilization created such a machine
不管怎么说，如果过去10亿年间有外星文明造出了类似的机器，
and set it multiplying its way toward us, our galaxy would be swarming with them by now.
通过不断复制的方式向我们驶来，我们的银河系应该已经到处都是这些机器了。
So then where are all these machines?
但是那些机器在哪儿呢？
Some astronomers, like Carl Sagan, say that intelligent aliens wouldn't build self-replicating machines at all.
一些天文学家，比如卡尔·萨根，说聪明的外星人不可能建造自我复制机器。
They might hurtle out of control, scavenging planets to their cores in order to keep replicating.
这些机器会在横冲直撞后失去控制，为了实现自我复制把星球洗劫一空。
Others take the machines absence as proof that intelligent alien civilizations don't exist,
另外一些人认为这种机器不存在，是因为根本不存在智慧的外星文明，
or that they go extinct before they can develop the necessary technologies.
或者在他们发展出必要科技前就已经灭绝了。
But all this hasn't stopped people from imagining what it would be like if they were out there.
但这些想法并不妨碍人类想象，如果存在外星文明将是怎样一番景象。
Science fiction author David Brin writes about a universe in which many different von Neumann machines exist and proliferate simultaneously.
科幻小说作家大卫·布林描写了一个存在许多不同的冯·诺依曼机器并同时扩散的宇宙。
Some are designed to greet young civilizations, others to locate and destroy them before they become a threat.
一些机器跟年轻文明打招呼，另一些则定位年轻文明，并且在年轻文明成为威胁前将其摧毁。
In fact, in Brin's story 'Lungfish,' some von Neumann machines are keeping a close watch over the Earth right now,
实际上，在布林的小说“Lungfish”里面，一些冯·诺依曼机器正密切关注着地球，
waiting for us to reach a certain level of sophistication before they make their move.
等我们成熟到一定阶段后他们才采取行动。
For now, all we have is curiosity and theory.
目前，我们有的只是好奇心和理论。
But the next time you look at the night sky,
但下次你仰望夜空时，
consider that billions of self-replicating machines could be advancing between stars in our galaxy right now.
想象无数自我复制的机器正在银河系的恒星间穿梭。
If they exist, one of them will eventually land on Earth, or maybe, just maybe, they're already here.
如果它们存在，最后一定会降临地球，也许，它们已经到地球了。
