正文翻譯
原創翻譯：龍騰網 http://www.ltaaa.com 翻譯：君子衝盈 轉載請註明出處
Krister Sundelin, UX Writer at HiQ G?teborg (2011-present)
If there are aliens, why do they not invade Earth?
Any advanced alien species would come from at least 4.5 light-years away, and probably a lot more. But let’s go for best case: 4.5 light-years. That’s the distance light travels in 4.5 years. Using our best rocket technology, it takes us about 80,000 years. Using the best rocket technology we can imagine, we could make the journey in 50 years.
So if they can get an invasion fleet here in any time for an invasion to be practical, they’re ludicrously advanced. Possibly they have access to technology that we can barely imagine. Let’s imagine that they have something like an Alcubierre drive. They would have access to or knowledge to make matter with negative energy density, and they would have all their practical energy needs satisfied.
如果有外星人，為什麼他們不入侵地球？
任何先進的外星物種都至少來自4.5光年以外，或許更遠，但讓我們看看最好的情況： 4.5光年，這等於光傳播4.5年所走過的距離。
使用我們最先進的火箭技術，我們需要8萬年的時間，使用我們能想象到的最好的火箭技術，我們可以在50年內完成這一旅程。
因此，如果他們可以在任何時候在這樣的距離部署入侵地球的艦隊，那麼他們就可以說是十分先進，也許他們能接觸到我們幾乎無法想象的技術。
我們想象一下，他們會有類似曲速驅動引擎的東西，他們有機會或相應知識製造負能量密度的物質，他們將滿足所有實際的能源需求。
The point is: if you can traverse the depths of interstellar space with an invasion fleet, you’re so advanced that you have no reason to invade a planet. Every need you might imagine for invading a planet can be easier solved in space with the resources that are there and uncontested.
Except, perhaps, if it is about religion.
關鍵是：如果你能用一支入侵艦隊穿越廣漠的星際深空，你已經非常先進了，沒有理由去入侵一顆行星。
你能想象到每一個入侵行星的需求都可以在太空中更容易地解決，因為那裡有無可爭議的資源。
當然，如果涉及（外星人）宗教的話，情況可能會不一樣。
評論翻譯
原創翻譯：龍騰網 http://www.ltaaa.com 翻譯：君子衝盈 轉載請註明出處
Christophe Meessen
This question is based on the assumption that an alien invasion of earth would be perceivable like the invasion of the American continent by Europeans. But one should keep in mind that aliens may have, are, or might invade earth in an non-perceivable way.
Any action made by any living entity is motivated by a benefit. There must be an advantage that outbalance the risk and consequences of a negative reaction.
ET reaching earth, if any, must have master the energy source to do so. So energy can’t be the motivation. Materials might also be mastered and there is plenty in space, even water. ET have spaceships perfectly adapted for them and space travels. They can move, escape and hide with a spaceship. They can’t do that on earth. We are currently vulnerable to a collision with asteroids or whatever, they are not.
這個問題是基於這樣一個假設，即外星人入侵地球會像歐洲人入侵美洲大陸一樣可以被感知。
但是我們應該記住，外星人可能已經，正在，或者可能以一種不可察覺的方式入侵地球。
任何活著的實體所採取的任何行動都是出於利益，而且還必須存在某種優勢能夠抵消消極反應的風險和後果。
到達地球的外星人—— 如果存在的話——必須掌控能量源才能做到這一點，所以能源不可能是其動機。
還必須掌控材料，太空中有足夠的空間，甚至水，外星人擁有完美適應他們的太空飛船和太空旅行，他們可以移動，逃跑，躲藏在宇宙飛船裡，但他們在地球上不能這麼做，我們現在很容易受到小行星撞擊或者其他什麼的影響，但他們不會。
The element of value we have on earth is our genetic material which is the product of billion years of evolution. That is what might interest ET and they don’t need to invade earth for that. They only need to collect samples and eventually create hybrids in their spaceships if they consider it of value.
We currently don’t know if there are plenty ET civilization more advanced than us, and if they have full liberty of movement. It could be that there is a fundamental law of life among them that is to respect the development of any life form. Any civilization that would not respect this law would represent a threat to the others. This is what is more or less happening between countries on earth.
There may be other reasons, which we are not aware of yet.
對外星人來說，地球上擁有的最具價值元素可能是是我的遺傳物質，它是億萬年進化的產物，這一點到是可能會引起外星人的興趣，但他們不需要為此入侵地球啊，如果他們認為它有價值，他們只需要收集樣本，在他們的太空船就能創造出相應的混血兒。
我們目前不知道是否有很多比我們更先進的外星文明，也不知道他們是否有充分的行動自由。
可能在他們之中有一個基本的生命法則，那就是尊重任何生命形式的發展。
任何不遵守這一規則的文明都將對其他文明構成威脅——地球上的國家之間或多或少存在這樣的規則。
Human beings have been around what, 100,000 years? Yet that’s just one-billionth of the expected lifespan of the universe. We exist at a very tiny scale, both in terms of time and distance.
Just 10 billion years after the universe started, we know life evolved on Earth. But the Earth has had intelligent life for just the past 1/30,000th of its existence. For aliens to find us, they would have to exist in the same teeny blip of time we occupy.
Spacefaring civilizations may pass each other like trains in the night, with trillions of miles and hundreds of millions of years separating them. Not only are their planets incredibly far apart, but they don’t even coexist in anywhere near the same time frx.
人類大概有10萬年的歷史了吧？ 然而，這僅僅是宇宙預期壽命的十億分之一，我們存在於一個非常微小的尺度，無論是時間還是距離。
在宇宙誕生100億年後，地球上的生命進化了，但是地球在過去的三萬分之一的時間裡都有智慧生命，要讓外星人找到我們，他們必須和我們生活在同一點的時間裡。
太空文明可能會像夜間的火車一樣彼此擦肩而過，相隔數萬億英里、數億年，他們的行星不僅相距遙遠，而且他們甚至不能在同一時間段內共存。
小行星撞擊地球造成大規模物種滅絕的可能性要大得多。
Kevin Stern, B.S. Computer Information Systems (1997)
Why would they? We pose no threat to any civilization advanced enough to travel the stars. Especially being basically grounded. We’re in a lonely arm in the Galaxy. Not much strategic means there. We have little to offer an advanced civilization because we’re primitive to them.
Food/ i doubt any species will travel the universe, abducting various creatures to test for how edible, nutricous, or delicious they are. And really, can you imagine going through all that trouble of invading, killing, being killed, just for a Happy Meal? I doubt we’d make good slaves, and if they study our media, they’d know we don’t take kindly to slavery (least of all white people, who insist on being the slavers). Again, an awful lot of trouble to round up some slaves that will revolt the first chance they get. Resources? Again, why risk destruction in a war?
It really makes little sens to be invading other worlds, considering the time, technology, danger, and various other reasons. Sure, it could happen, but it sure hasn’t happened in our collective history. In fact, if you want to believe the ancient aliens theory, any alien contact has been rather peaceful.
他們為什麼要這麼做？ 我們對任何足夠先進到可以星際旅行的文明都不構成威脅。
尤其是我們基本上形同被“禁足”，我們生活在銀河系的孤獨的臂膀裡，這裡沒有多少戰略意義。
我們幾乎沒有一個足夠先進的文明，我們對他們來說是原始的。
為了食物？ 我懷疑是否會有物種會在宇宙中旅行，無聊到綁架各種各樣的生物來測試它們的食用性、營養性或美味程度。
說真的，你能想象為了一頓開心樂園餐而費盡周折地入侵、殺戮嗎？
奴隸？ 我懷疑我們是否能成為好的奴隸，如果他們研究我們的媒體，他們就會知道我們對奴隸制並不友好 ( 尤其是堅持要當奴隸販子的白人)，為了圍捕那些一有機會就會反抗的奴隸，實在不值得，也會有很多麻煩。
資源？ 有必要在戰爭中冒著毀滅的危險去獲得資源？
考慮到時間、技術、危險和其他各種各樣的原因，入侵其他世界確實毫無意義。
當然，這種情況有可能發生，但在我們的集體歷史中肯定沒有發生過，事實上，如果你相信《遠古外星人的》理論，任何外星人的接觸都是相當和平的。
Rebecca Harbison, General purpose nerd
There’s a lot of steps between premise A and B that might prevent it.
Alien doesn’t necessarily mean intelligent or technological. If we find microbes on Enceladus, they aren’t invading anything.
(Aside: if we find microbes in the solar system, the glib answer is ‘they may already have’. There is a reason NASA has a whole office devoted to making sure our space probes (especially landers, especially anything heading to Mars or an icy satellite with a sub-ice ocean) are squeaky clean. Microbes are a lot better at surviving hostile conditions than us big multi-cellular organisms )
We don’t know what aliens are like. Maybe most intelligent species live on places like Enceladus, and think planets with open skies are creepy. Heck, maybe they live on places like Titan, and see us as weird creatures based on molten ice.
在前提 a 和前提 b 之間有很多步驟可能阻止它。
外星人並不一定意味著智能或技術，如果我們在土衛二上發現微生物，它們不會入侵任何東西。
( 除此之外：如果我們在太陽系中發現了微生物，那麼一個簡單的答案是“他們可能已經發現了”。NASA有一整個辦公室致力於確保我們的太空探測器 ( 特別是著陸器，尤其是任何前往火星或冰層以下海洋的衛星 ) 是潔淨無瑕的，這是有原因的，微生物比我們這些大型多細胞有機體在惡劣條件下生存得更好。)
我們不知道外星人是什麼樣的。
也許大多數智能物種生活在像土衛二這樣的地方，並認為擁有太空旅行能力的行星是令人毛骨悚然的，見鬼，也許他們生活在土衛六這樣的地方，把我們看成是基於基於熔融冰的怪異生物。
Space travel is hard. Humans still couldn’t invade anything off Earth, and we’ve actually been to space. We haven’t even sent people past the Moon. But we’ve existed as a species for hundreds of thousands of years. So that’s a tiny proportion of time for us to be space invaders, even if we land people on Mars tomorrow.
No, seriously, space travel is hard. Currently it would take us generations to get to the nearest place that might have a habitable planet. Which we haven’t identified yet — we just know the planets in our solar system are pretty hostile for life like us. And that is a limit as far as we know: nothing can travel at or above the speed of light that starts slower than light. That also means you need to dedicate an invasion and colonizing force at once, as by the time you get the news, it is way too late to send reinforcements.
They have better things to do with their time. If aliens could live in space for decades or centuries enough to get to Earth, and send a whole army/support/colony staff, why bother taking over someone else’s planet at all?
Francesco Maddalena, Msc. Nanoscience / PhD Physics
Well why should they in the first place?
In any case there are several reasons:
They do not exist (not anywhere in our galaxy or galaxy cluster at least)
They don’t have the technology to reach us or mount an invasion. I mean imagine we discovered Mars was inhabited by little green men with similar tech level as us. We would be NOWHERE near mounting an invasion. We are not even ready to send a few people there!
They are too far. Perhaps physics prevents all to travel faster than light. This would basically forbid any Alien civilization to conquer us unless they were willing to spend hundreds of years in space… Still even so logistically it would be nearly impossible
They don’t care about us (why should they really? Is Earth the only piece of prime real estate in the galaxy?)
They do not want to interfere with us (like Prime Directive in Star Trek)
They have very low technological level (we might as well be the most advanced in the galaxy as far as it goes)
There is no sentient life (near enough to us) except for us
那麼，首先，他們為什麼要這樣做呢？
無論如何，有以下幾個原因：
它們不存在 ( 至少在我們的星系或星系團中不存在 )
他們沒有技術來接近我們或發動入侵。
我的意思是，想象一下，我們發現火星上居住著和我們技術水平相當的小綠人，我們根本不可能發動入侵，我們甚至還沒準備好派幾個人去那裡！
他們太遠了。
也許物理學阻止了一切超光速的運動，這將基本上禁止任何外星文明徵服我們，除非他們願意在太空中度過數百年...... 儘管如此，從邏輯上講，這幾乎是不可能的。
他們不關心我們 ( 他們為什麼要關心我們？ 地球是銀河系中唯一的黃金地段嗎? )
他們不想幹涉我們 ( 正像《星際迷航》中的《最高指令》所述 )
它們的技術水平非常低 ( 就目前而言，我們可能是銀河系中最先進的 )
除了我們之外，沒有任何有知覺的生命 ( 離我們足夠近 )
Bill Hitchens, Logical and Critical Thinking, University of Auckland
The Earth is an unremarkable planet out in the middle of nowhere.
Even if they can see the planet, it’s unlikely that they can see anything about us. They might be able to tell there’s life, but that’s about it.
Space travel is expensive and hard. You need to make sure you’re doing it for a worthwhile cause.
Invading Earth doesn’t get you anything you can’t find elsewhere.
You want diamonds? There are planets made of diamond.
You want slaves? Robots are far more efficient than people could ever be.
Whatever technology the aliens might use to get here would be better used to get them what they actually want.
在茫茫荒野中，地球是一顆不起眼的行星。
即使他們能看到地球，他們也不可能看到我們的任何東西，他們也許能分辨出生命的存在，但僅此而已。
太空旅行既昂貴又困難， 你需要確保你是為了一個有價值的事業而做這件事。
入侵地球不會給你帶來任何你在別處找不到的東西。
你要鑽石？有些行星是由鑽石構成的。
你要奴隸？機器人遠比人類更有效率。
無論外星人可能使用什麼技術來到達這裡，都比他們真正想要的東西要好。
Andrew Wrigley, Earth is neither flat nor round. It bulges at the middle.
Why on Earth would aliens invade Earth when it is jam packed with the kind of seriously aggressive and destructive beings that are humans, hell bent, into the bargain, on destroying Earth and quite capable of doing it without any help from outer space?
Never mind trying to get here across the intractable vastness of space?
Or being greeted by Donald Trump, who has just invaded the UK because Jeremy Corbyn is a loser who has refused to nuke the incoming aliens?
I think you get my drift, but just in case:
If these aliens are so bloody intelligent that they can not only get here but also invade us, then this is the last shit hole in the local cluster they will bother to visit.
Or invade.
地球上擠滿了極具侵略性和破壞性的生物，人類拼命摧毀地球，而且完全有能力在沒有外太空幫助的情況下摧毀地球，為什麼外星人還要入侵地球？還嘗試著穿越這難以駕馭的浩瀚太空來入侵地球？
還是為了受到唐納德 · 特朗普的歡迎，他剛剛入侵英國，因為傑里米 · 科爾賓是一個拒絕用核武器攻擊外星人的失敗者？
我想你明白我的意思，但以防萬一我說清楚點：
如果這些外星人是如此的聰明，他們不僅可以到達這裡，而且還可以入侵我們，那麼這裡就是他們最不願意來的地方。
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