Could human civilization spread across the whole galaxy? - Roey Tzezana

Translator: Jessica Ruby Reviewer: Brian Greene

譯者: Henry Black 審譯者: 庭芝 梁

Could human civilization eventually spread across the whole Milky Way galaxy?

人類文明能散播到 整個銀河系嗎？

Could we move beyond our small blue planet

我們能夠離開地球，

to establish colonies in the multitude of star systems out there?

到眾多的星系中 建立殖民地嗎？

This question's a pretty daunting one.

這個問題其實有點令人氣餒。

There are around 300 billion stars in the galaxy,

銀河系中有約3000億個星體，

which is about 160,000 light-years across.

距離橫跨16萬光年。

So far we've sent a single spacecraft outside our solar system,

而目前我們只能將一個飛行器 送出太陽系，

trudging along at 0.006% of the speed of light.

而它只能以 光速的0.006%倍速度旅行。

At that rate, it would take over 2.5 billion years

依照這樣的速度， 得花費超過25億年

just to get from one end of the galaxy to the other.

才能到達銀河系的另一端。

And then there's the question of human survival.

而且人類如何生存 也是個問題。

The gulf between stars is simply enormous.

每個星體的距離都非常遙遠，

We couldn't live sustainably on most planets,

況且大多數的行星 都不宜人居，

and we require a lot of resources to stay alive.

但人類需要很多資源才能生活。

And yet, decades ago, scholars found that it's theoretically possible

然而，幾十年前有學者發現 在理論上這是可行的，

to not just spread human civilization across the galaxy,

不只是將人類文明 散播到整個銀河系

but to do so quite quickly,

而且速度又很快，

without breaking any known laws of physics.

也不需要打破任何物理定律。

Their idea is based on the work of a mathematician named John von Neumann,

這樣的想法是根據數學家 約翰·馮·諾伊曼

設計的一種理論機器， 不但具有自我複製能力，

who designed on paper machines that could self-replicate

and create new generations of themselves.

而且能不斷繁殖後代。

These would later come to be known as von Neumann machines.

這個想法被後人稱之為 馮·諾伊曼飛行器。

In the context of space exploration,

進行太空旅行時，

von Neumann machines could be built on Earth

馮·諾伊曼飛行器 可於地球上製造，

and launched into space.

再發射到外太空。

There, the self-sufficient machines would land on distant planets.

這些能自給的機器 會登陸遙遠的行星。

They would then mine the available resources and harvest energy,

然後鑽探可取得的資源 並獲取能量，

build replicas of themselves,

複製更多個體，

launch those to the nearest planets,

再發射到附近的行星，

and continue the cycle.

不斷重複以上的循環。

The result is the creation of millions of probes

最終便會產出 幾百萬台飛行器，

spreading outwards into the universe like a drop of ink in a fishbowl.

如同滴入水缸中的墨水般 不斷向宇宙擴散。

Scholars crunched the numbers and found that a single von Neumann machine

學者們經過不斷計算之後發現，

traveling at 5% of the speed of light

如果每台飛行器 以5%的光速飛行，

should be able to replicate throughout our galaxy in 4 million years or less.

大概400萬年以內 就能遍布整個銀河系。

聽起來或許很久，

That may sound like a long time,

but when you consider that our universe is 14 billion years old,

但想到宇宙已經有140億年的歷史時，

on a cosmic scale, it's incredibly fast -

以宏觀的角度而言是非常快的，

the equivalent of about 2.5 hours in an entire year.

只相當於一年中的2.5個小時，

Creating von Neumann machines would require a few technologies

製造馮·諾伊曼飛行器 需要幾項關鍵技術，

we don't have yet,

目前還沒研發出來，

including advanced artificial intelligence,

包含更先進的人工智慧，

miniaturization,

縮小技術，

and better propulsion systems.

還有改良的推進系統。

If we wanted to use them to spread actual humans throughout the galaxy,

如果我們想傳送真正的"人類"，

we would need yet another technological leap -

我們必須再發生一次科技大躍進，

the ability to artificially grow biological organisms and bodies

發展出以人工方式培養器官，

using raw elements and genetic information.

還有使用原料跟基因資訊 培養人體的技術。

Regardless, if in the last billion years

除此之外， 如果過去數十億年當中，

an alien civilization created such a machine

已經有外星文明 製造出這樣的機器，

and set it multiplying its way toward us,

並且不斷在宇宙中擴散的話，

our galaxy would be swarming with them by now.

現在銀河系當中 早就到處都有那些機器了。

So then where are all these machines?

可是那些機器在哪裡呢？

Some astronomers, like Carl Sagan,

卡爾賽根等天文學家認為，

say that intelligent aliens wouldn't build self-replicating machines at all.

有智慧的外星生物 是不會製造這種機器的，

They might hurtle out of control,

因為有可能會失控，

scavenging planets to their cores in order to keep replicating.

為了持續繁殖 而侵蝕星球的核心。

Others take the machines absence as proof

其他人則認為 這些機器沒有出現，

that intelligent alien civilizations don't exist,

證明了高度智慧的外星文明 仍然不存在，

or that they go extinct before they can develop the necessary technologies.

又或者是這些文明 在研發出必要的科技前就滅絕了。

But all this hasn't stopped people from imagining what it would be like

但這並不會停止人們去想像

存在宇宙中的外星生命。

if they were out there.

Science fiction author David Brin

科幻小說作家大衛布林

writes about a universe in which many different von Neumann machines exist

曾描述過一個宇宙 存在著各種馮·諾伊曼飛行器，

and proliferate simultaneously.

同時他們也不斷地繁殖擴散。

Some are designed to greet young civilizations,

有些是去拜訪剛發展出來的文明，

others to locate and destroy them before they become a threat.

有些則是會在 文明成為威脅前摧毀他們。

In fact, in Brin's story "Lungfish,"

事實上，在布林所寫的 《肺魚》(Lungfish)故事中提到，

some von Neumann machines are keeping a close watch over the Earth right now,

有些馮·諾伊曼飛行器 正密切監視著地球，

waiting for us to reach a certain level of sophistication

等待我們的文明發展到某種程度

before they make their move.

再做出行動。

For now, all we have is curiosity and theory.

目前為止我們所說的 還只是理論和好奇而已。

But the next time you look at the night sky,

下次當你凝望夜空的時候，想像一下

consider that billions of self-replicating machines

有數十億台能自我繁殖的機器

could be advancing between stars in our galaxy right now.

正在銀河系中行進。

If they exist, one of them will eventually land on Earth,

如果真的有， 其中一台一定會來到地球。

or maybe, just maybe, they're already here.

但也有可能，只是可能而已， 其實它們已經到了。