Why Can't We See Evidence of Alien Life?

為什麼我們還找不到外星生命存在的證據?

譯者: Yu-Sheng Lin 審譯者: Chen-Han Hsiao

(片頭)

在浩瀚無垠的宇宙中

Somewhere out there in that vast universe,

必然有無數其他行星充滿生命，

there must surely be countless other planets teeming with life,

但是，為什麼我們沒有找到任何的證據呢？

but why don't we see any evidence of it?

嗯，這就是 恩裡科 · 費米 在 1950 年提出那個著名的疑問:

Well, this is the famous question asked by Enrico Fermi in 1950:

"Where is everybody?"

"其他人在哪裡？"

Conspiracy theorists claim that UFOs are visiting all the time

陰謀論者宣稱, 其實一直都有幽浮(UFO)到地球來

and the reports are just being covered up,

只是所有的報告都被掩蓋掉了

but honestly, they aren't very convincing.

但坦白地說，這種說法不太有說服力。

But that leaves a real riddle.

所以這個疑問還是一直存在著.

In the past year, the Kepler space observatory

在過去一年，克卜勒太空望遠鏡已找到

has found hundreds of planets just around nearby stars,

鄰近我們的一些恆星週邊的數以百計的行星

如果用這些數據來推論

and if you extrapolate that data,

it looks like there could be half a trillion planets

應該有將近5000億個行星

光只算我們自己這個銀河系.

just in our own galaxy.

If any one in 10,000 has conditions that might support a form of life,

如果每一萬個行星中只有一個

能夠發展出某種的生命形態, 那就相當於

that's still 50 million possible life-harboring planets

有 5000 萬個行星可能有生命

right here in the Milky Way.

就在我們的銀河系裡

所以這裡就是疑問所在了:

So here's the riddle.

Our Earth didn't form

我們的地球一直到 "大霹靂" 的約 90 億年後才形成。

until about 9 billion years after the Big Bang.

在我們的銀河系中的許多其他行星

Countless other planets in our galaxy should have formed earlier

應該有可能形成得更早，並且有機會發展出生命

and given life a chance to get underway

比地球的生命發生, 早個幾十億年,

billions or certainly many millions of years

earlier than happened on Earth.

或者是幾百萬年的時間.

If just a few of them had spawned intelligent life

如果其中有些發展出了具有智慧的生命形態

and started creating technologies,

並且開始創造各種科技

這些技術會有數百萬年的時間

those technologies would have had millions of years

可以發展到很複雜, 很強大

to grow in complexity and power.

在地球上，

On Earth,

我們已經看到科技的發展

we've seen how dramatically technology can accelerate

在短短 100 年間能達到如此驚人的地佈

in just 100 years.

如果有數百萬年的時間，有智慧的外星文明

In millions of years, an intelligent alien civilization

could easily have spread out across the galaxy,

應該很容易傳播到整個銀河系

perhaps creating giant energy-harvesting artifacts,

也許創造出了巨大的能量收集工具

or fleets of colonizing spaceships,

或是 殖民太空船的艦隊

or glorious works of art that fill the night sky.

或是 塞滿整個夜空的 發亮的藝術作品。

至少，你會認為他們應該會有意或無意的

At the very least, you'd think they'd be revealing their presence,

藉著某種型態的電磁信號

deliberately or otherwise,

暴露他們存在的事實

through electromagnetic signals of one kind or another.

然而，我們從未看到任何令人信服的證據。

And yet we see no convincing evidence of any of it.

這是為什麼呢？

Why?

Well, there are numerous possible answers,

嗯，有許多可能的答案，

some of them quite dark.

有些人想得比較灰暗。

Maybe a single, superintelligent civilization

或許有一個單一的超級智慧文明

實質上接管了整個銀河系，

has indeed taken over the galaxy,

and has imposed strict radio silence

並且實行嚴格的無線電靜默管制

because it's paranoid of any potential competitors.

只為了不讓任何潛在的競爭對手出頭

It's just sitting there ready to obliterate

它只在那裡等待著殲滅

anything that becomes a threat.

所有可能變成威脅的文明

Or maybe they're not that intelligent.

或許他們沒有那麼高的智慧

Or perhaps, the evolution of an intelligence

又或許某種智慧生物的演進

capable of creating sophisticated technology

以經能夠創建尖端的技術

is far rarer than we've assumed.

比我們能猜想的還要稀奇許多

After all,

畢竟，智慧生命在40 億年間, 只在地球上發生了一次

it's only happened once on Earth

in 4 billion years.

Maybe even that was incredibly lucky.

這或許是難以置信的幸運狀況

Maybe we are the first such civilization in our galaxy.

或許我們是這個銀河系裡第一個發展出文明的。

也有可能文明發展的本身, 同時也帶著

Or, perhaps, civilization carries with it

the seeds of its own destruction

自我毀滅的種子

through the inability to control the technologies it creates.

因為對自己所發展出的技術失去了控制的能力。

但還有許多更有希望的答案。

But there are numerous more hopeful answers.

For a start, we're not looking that hard,

比方說，我們找得還不夠認真。我們投入的經費少得可憐。

and we're spending a pitiful amount of money on it.

銀河系中恒星只有微不足道的一小部分

Only a tiny fraction of the stars in our galaxy

have really been looked at closely for signs of interesting signals.

真的被仔細觀察過, 看有沒有特殊的訊息徵象。

也許我們沒有用對的方式來觀察

And perhaps, we're not looking the right way.

也許隨著文明的發展，

Maybe as civilizations develop,

they quickly discover communication technologies

外星人很快發展出新的通信技術

far more sophisticated and useful than electromagnetic waves.

比電磁波更複雜先進而且好用。

也許所有的動靜, 都是發生於

Maybe all the action takes place

inside the mysterious recently discovered dark matter,

最近才發現的神秘的 "暗物質"

or dark energy,

或是 暗能量，這些佔有宇宙質量的大部分組成。

that appear to account for most of the universe's mass.

又或者，我們觀察的尺度不對

Or maybe we're looking at the wrong scale.

也許這些智慧文明已經了解到

Perhaps intelligent civilizations come to realize

that life is ultimately just complex patterns of information

生命的極致, 只是一些形式複雜的資訊

interacting with each other in a beautiful way,

以美麗的方式彼此間互動

and that can happen more efficiently at a small scale.

而這樣的事情在更小的尺度可以更有效的進行

So just as on Earth, clunky stereo systems have shrunk to beautiful, tiny iPods,

就如同在地球上，笨重的立體音響

已經被縮小成美麗又精巧的 ipod，也許智慧生命本身，

maybe intelligent life itself,

為了減少它的環境足跡 (對環境的影響)

in order to reduce its footprint on the environment,

has turned itself microscopic,

所以已經演化成微小的型態

so the Solar System might be teeming with aliens,

如果真的是這樣，那太陽系可能一直充滿了外星人，只是我們沒有注意到他們。

and we're just not noticing them.

也許在我們大腦中的許多念頭, 本身就是一種外星生命。

Maybe the very ideas in our heads are a form of alien life.

Well, okay, that's a crazy thought.

嗯，好吧，這想法太瘋狂了.

The aliens made me say it.

是外星人害我這樣說的.

But it is cool that ideas do seem to have a life all of their own,

但這真的很酷, 想法本身就像是有生命的

而且存活得比產生想法的人還久

and that they outlive their creators.

也許生物型態的生命, 只是一個過渡型態。

Maybe biological life is just a passing phase.

在未來的 15 年裡

Well, within the next 15 years,

we could start seeing real spectroscopic information

我們將能開始觀察到五花八色的資訊

from promising nearby planets

來自於鄰近的這些行星, 並發掘出這些行星有多少可能性發展出生命

that will reveal just how life-friendly they might be.

在此同時, SETI計畫, (SETI 是搜尋外星智慧的縮寫)

And meanwhile SETI,

the Search for Extra-Terrestrial Intelligence,

也持續提供資料給大眾

is now releasing its data to the public

so that millions of citizen scientists, maybe including you,

讓數以百萬計的平民科學家參與，也許包括你在內

can bring the power of the crowd to join the search.

將群眾的能量帶入研究體系共同努力。

在地球上，還有許多令人驚異的實驗在進行著

And here on Earth, amazing experiments are being done

嘗試從頭開始創造生命

to try to create life from scratch,

life that might be very different from the DNA forms we know.

這種生命可能與我們熟知的 DNA 形態大不相同

All of this will help us understand

所有這一切都是為了要解答那個疑問:

宇宙是否充滿各種生命?

whether the universe is teeming with life

or, whether indeed,

抑或是，真的只有我們而已

it's just us.

不管答案是什麼，背後的道理

Either answer, in its own way,

is awe-inspiring,

都會是令人驚歎的

because even if we are alone,

因為即使我們是唯一的

the fact that we think and dream,

我們 思考, 夢想, 探究 這些問題的這檔子事

and ask these questions

有可能變成是關於宇宙的最重要的事情之一

might yet turn out to be one of the most important facts

about the universe.

我還有一個好消息要告訴你

And I have one more piece of good news for you.

The quest for knowledge and understanding never gets dull.

對於知識和理解的追尋, 是永遠不會變得枯燥乏味的

It doesn't. It's actually the opposite.

不僅不會乏味, 相反的, 你知道得越多

The more you know,

the more amazing the world seems.

就會覺得這個世界越神奇

And it's the crazy possibilities, the unanswered questions,

而這些瘋狂的可能性, 未被解答的疑問,

that pull us forward.

就是我們前進的動力, 所以, 請繼續好奇下去.

So, stay curious.