With more than 100 billion galaxies in the observable universe and at least 500 billion planets in the Milky Way alone, don't you think we should have found something by now?

在可視宇宙超過一千億個星系、單銀河系至少也有五千億顆行星的狀況下，你不覺得我們到現在應該找到些什麼了嗎？

Even if a tiny percentage of those billions of planets hosted intelligent life, there would be tens of thousands of extraterrestrial civilizations out there.

即使數十億行星中只有一小部分養育著智慧生命，太空中應該也會有數萬個外星文明。

Yet, we haven't seen any.

然而我們至今一個都沒看到。

We keep wondering, "What's taking them so long to come?"

我們不停在想：「是什麼東西拖延了牠們到臨的時間？」

But what if I told you that even the friendliest of all aliens could wipe out our entire civilization for good?

但如果我跟你說，就連最友善的外星人都可以徹底殲滅我們整體文明，你會怎麼想？

This is "What If", and here's what would happen if aliens visited us tomorrow.

這是《What If》，如果外星人明天到來，即將發生以下這些事。

We tend to apply our theories to the rest of the Universe.

我們一般會將我們的理論套在宇宙其它地方。

We expect aliens to come for a visit, even though we ourselves haven't traveled out of our own neighborhood yet.

我們期待外星人造訪，儘管我們自己至今還沒有旅行至鄰近星球。

We just believe that they've had so much more time for technological progress to make space travel possible.

我們只是相信牠們有更多的時間促成科技進步，使得太空旅行變成可能。

So, here they are, with their shiny alien spaceship roving above our heads.

好啦，牠們來了，閃閃發亮的外星太空船在我們頭頂上漫遊。

What would we do?

我們會怎麼做？

As far as we know, no government on this planet has any sort of alien-greeting party planned if aliens suddenly showed up on the horizon.

就我們所知，如果外星人突然出現在地球，世界上沒有任何一個政府籌備好外星人歡迎派對。

Just try to keep cool.

只要盡量保持冷靜。

Say the aliens happened to be very polite and sent us a signal before invading our planet's personal space.

假設外星人剛好很有禮貌，侵犯地球上個人空間前發送了訊號給我們。

Well, you wouldn't know it right away.

那你也不會馬上知道。

Not until several observatories maintained by different organizations verified that signal.

還要等到數個由不同組織管理的觀測站證實那則訊號。

Yep, that's it.

沒錯，就是這樣。

Aliens are here.

外星人來了。

Now you know.

現在你知道了。

You got this shocking news from your TV.

你從電視當中得知這則驚人的新聞。

NASA officially confirmed....

美國太空總署正式證實⋯⋯

And a alien ship detected in the Solar System...

而太陽系中偵測到的一艘太空船⋯⋯

... not alone in the universe.

⋯⋯在太空中不是獨自存在的。

Agencies and countries around the world would be working together, quickly trying to assess the level of threat.

世界各地的機關以及國家將合作，試圖快速地評估威脅程度。

They'd summon experts in linguistics, psychology, combat, and biology and have them attempt to make first contact with the aliens.

他們會招集語言學、心理學、戰鬥學及生物學等專家，並讓他們試圖與外星人做第一次接觸。

Groups of experts would record all interactions to analyze simple alien gestures and auditory reactions.

專家群會記錄所有的互動以分析簡單的外星人手勢以及聽覺反應。

Those would help to decide whether aliens came in peace or they intend to do some serious damage.

那些將有助於決定外星人是和平到來或是打算做出嚴重傷害。

Some people might believe that religious leaders should do all the talking.

有些人可能會相信應該由宗教領袖進行所有對談。

Something's telling me that aliens didn't learn our languages in school, so...

我認為外星人在學校時應該不會學習地球的語言，所以說⋯⋯

... good luck to anyone trying to reach out to them.

⋯⋯對任何想要跟牠們溝通的人，我只能祝他好運。

While the world's most intelligent people were busy trying to interpret the aliens' intentions to the best of their ability, you would be⏤wait!

當當世界上最聰明的人們竭盡全力忙著嘗試解讀外星人的意圖時，你將會──等等！

Aren't you curious to know what the aliens look like?

你不好奇外星人的樣貌嗎？

Some evolution experts agree that things like proteins and DNA are the same no matter where in the universe you're from.

一些演化論專家都認同，無論你來自宇宙的哪個地方，諸如蛋白質以及 DNA 等物質都是一樣的。

If that's true, alien evolution would be close to that of humans.

如果那是真的，外星人的演化會跟人類的很相近。

They'd have binocular vision with eyes located close to the brain.

牠們會擁有雙眼視覺，眼睛位置會靠近腦部。

Just like us, they'd be based on land and have a minimum of two legs for mobility and three fingers so that they could handle tools.

就像我們一樣，牠們將以陸地生活為主，並至少有兩條腿用以活動以及至少三隻手指頭來使用工具。

Still, if some of our own life forms look like this, try to picture something coming from another planet.

儘管如此，如果我們地球上可能有長成這樣的生物，試著想像來自另一個星球的生物。

Meanwhile, on Earth, while governments were busy figuring out the action plan, the media would be keeping you informed.

在地球上，政府忙著訂定行動計畫的同時，媒體會讓你時時掌握資訊。

You'd be advised to stay indoors and wait for further instructions.

你會被建議要留在室內，等候進一步指示。

It'd be hard to filter out what's legitimate news and what isn't, but try not to fall for fake end-of-the-world news on Facebook and keep calm.

要過濾哪些是正當新聞也會是一件難事，但試著不要被臉書上虛假的世界末日新聞愚弄並保持冷靜。

At least make an effort to give up the urge to pack up your belongings and head for the hills.

至少要盡力讓自己壓抑打包家當、逃往山丘的衝動。

At the same time, the governments and scientific experts would be sharing information about alien interactions.

同時，政府以及科學專家將會分享與外星人互動的資訊。

From here, the events could unfold in a few different ways.

從此之後，情勢可能會以幾個不同方式發展。

First, we might not get any auditory or visual response.

首先，我們可能不會得到任何聽覺或視覺回應。

Nothing at all.

一點都沒有。

This could mean anything from the alien spacecraft doesn't have any aliens on board to the aliens are waiting for their alien backup to fry us up.

這可能意味各種情境，包含外星船上沒有任何外星人或是外星人正在等候後援來消滅我們。

Another possibility is that aliens responded and tried to communicate with no weapons involved.

另外一個可能性是，外星人會回應，並嘗試以無武力方式進行溝通。

I can't speak to their possible intentions.

我無法為牠們可能的意圖發表意見。

For all we know, they may want to get rid of us and keep the Earth to themselves.

就我們所知，牠們可能會想要根除人類，將地球佔為己有。

Thanks to the language barrier, our interactions might not be going well.

多虧了語言障礙，我們的互動非常可能不順利進行。

Tensions would begin to rise.

緊張感會開始上升。

We'd be screwed.

我們會很慘。

Considering that these beings had the technology to travel to Earth, it's likely that they also had the capability to develop some very, very advanced weaponry.

考量到這些生物有能夠旅行到地球的科技，牠們大概也有能力開發一些非常、非常先進的武器。

Civilians would most likely be hitting the panic button as hard as possible.

平民百姓大概會用盡全力按壓緊急按鈕。

Meanwhile, governments would put their nuclear weapons on standby.

同時，政府會確保所有核武準備就緒。

That would be our our best and most destructive weapon against them.

那將會是我們對抗牠們最好且最具毀滅性的武器。

Or so we think...

也可能是我們自以為⋯⋯

It may turn out that the aliens have adverse reactions to things on Earth that we are all accustomed to.

結果可能是，外星人對於地球上我們習慣的一切出現不良反應。

If, say, their skin melted upon contact with water, then defending ourselves against them would be simple.

假設牠們的肌膚接觸到水便會融化，那麼保衛自己對抗牠們就會很簡單。

I'm not saying aliens would necessarily bring doom upon the Earth.

我並不是說外星人一定會為地球帶來毀滅。

They might not mean us any harm at all.

牠們對我們可能一點惡意都沒有。

But if some hazardous microorganisms from outer space hitched a ride with them and made it into our world, we humans might have no natural immunity to those extraterrestrial microbes.

但如果外太空一些有害的微生物跟著牠們的太空船旅行並抵達地球，人類可能對這些外來微生物毫無天然抗體。

And they could slowly wipe our species off the planet.

那牠們就可能慢慢地讓我們的物種從地球上消失。

On the other hand, if aliens weren't coming here to make friends, we'd be destroyed long before we got a chance to offer peace between intelligent beings.

另一方面，如果外星人不是為了交朋友而來，我們可能早在有機會提出智能生物間的和平協議前，就被毀滅殆盡。

In any case, we aren't ready for a visit from interplanetary travelers.

無論如何，我們都還沒準備好迎接星際旅客的造訪。

We'd better get prepared for "first contact".

我們最好為了「第一類接觸」做足準備。

Or maybe we should try to invade alien worlds before they invade us.

又或許我們應該試著在外星人侵略地球前，侵略外星世界。

But that's a topic for another "What If".

但那是《What If》另一次的影片主題了。