On April 15th, 1912, an “Unsinkable ship” named the Titanic hit an iceberg and came

一九一二年四月十五日，名叫鐵達尼號，被稱作為「永不沉沒的船」撞上了冰山，

to rest nearly 4 kilometers beneath the surface.

沈入四公里深的海底深處。

Light?

有光線嗎？

None.

沒有。

The temperature?

溫度多少？

Two degrees Celsius.

攝氏兩度。

Pressures?

氣壓多少？

5000 pounds per square inch.

5000 磅每平方英寸。

But more than 100 years later, this watery graveyard is somehow teeming with life.

但是過了一百年以後，這個水裡的墳場不知怎麼地充滿了生命。

Those strange icicle shapes covering the Titanic are full of microscopic organisms that thrive

覆蓋在鐵達尼號上的那些奇怪冰柱狀上長滿了微生物，

in one of Earth's most inhospitable environments.

這些微生物正在地球上最惡劣的環境下茁壯生長。

They can literally *eat metal* and someday soon, they'll leave nothing but a rusty

它們真的可以吃金屬，而在將來的某一天，它們只會在原本船的地方留下

pile of powder where the ship once was.

一堆生鏽的粉末。

These deep-sea microbes are extremophiles, one of countless organisms living hidden in

這些深海微生物是嗜極生物，它們是居住在世界最極端的

Earth's most extreme habitats, adapted to conditions where, until recently, we figured

棲息地裡無數個生命中的其中之一，它們適應了原本我們以為

life couldn't exist.

不會有生命的環境。

Extremophiles have changed how we view life's possibilities on Earth.

嗜極生物改變了我們對於生命的可能性的看法。

They hold clues to how life may have taken hold on this planet, and also give us hints

它們身上有生命如何在這個星球上扎根的線索，也可以提示我們

about life's possibilities deep in space.

關於生命在太空深處的可能。

Off the Galapagos islands, 2 kilometers underwater, Earth's mantle and the ocean directly meet,

在加拉帕戈斯島下兩公里的深海處，地函和海交接的地方

creating strange, smoking vents with temperatures above 100˚C… yet home to ecosystems as

會產生奇怪和會冒煙的熱泉噴口，它們的溫度超過一百度，但是它們和熱帶雨林一樣

rich as any rainforest.

是非常多生態系的家。

At the base of this deep-sea food chain is a weird kind of single-celled life.

在深海食物鏈的底層有一個奇怪的單細胞生物。

Archaea.

古菌。

When it was discovered by Carl Woese, it completely redrew the tree of life.

當它被 Carl Woese 發現的時候，生命之樹完全被重畫。

They look a lot like bacteria–prokaryotes–but Archaea have unique internal machinery.

它們看起來很像單核細菌，但是古菌有獨特的生理系統。

And in Earth's most extreme habitats, we find them more often than any other life form.

而且相較於其他生物，我們發現在地球上最極端的棲息地裡古菌最常被找到。

Organisms adapted to high temperatures, can grow above 120˚C, hot enough to disintegrate

適應高溫的生物可以在高於一百二十度的環境下生長，這個溫度足夠分解

most cells' machinery.

絕大多數細胞的機能。

The microbes at these deep sea vents have unique adaptations like specially wound DNA,

生長在深海的微生物有特殊的適應，像是纏繞成不同形狀的 DNA

and putting extra bonds in their proteins to keep everything from melting.

和在蛋白質上增加多餘的鍵以防止所有的東西融化。

And it's not just single-celled life.

而且不止單細胞生物。

Larger organisms like tube worms and hairy crabs thrive in these super-hot ecosystems

比較大的生物像是管蠕蟲和毛蟹也生長在這些超級熱的

too.

生態系統裡。

This is a place completely devoid of light, where energy must instead be harvested from

這個地方完全沒有陽光，所以能量必須從地殼噴口所產生的

hydrogen and sulfur gases bubbling from the tectonic vents.

氫氣和硫磺中收集。

Not unlike conditions we expect to find on Jupiter's moon Europa, where the geologically

不像是我們預期在木星的衛星「木衛二」上看到的那個樣子，活躍的

active interior creates pitch black oceans of liquid water beneath its icy surface.

地質內部會在冰的底下製造黑色的液態水。

When it comes to pressure, we don't know what life's limits might be.

以壓力來說，我們並不知道生命的極限在哪裡。

The deepest places probed on Earth, like the Mariana trench, are home to microbial life

地球上偵測到最深的位置像是馬裏亞納群島是一些可以承受高壓的

able to withstand pressures more than a thousand times higher than we feel at Earth's surface.

微生物的家，它們可以承受的氣壓是我們在地球表面上的幾千倍。

And when scientists exposed other microbes to *low* atmospheric pressures like those

而且當科學家把其他的微生物也暴露在像是火星的那種低氣壓下，

on, say, Mars, many were like “no problem, this is fine”.

很多微生物都覺得沒有大礙。

But there ARE a couple things it seems life can't do without.

但是有幾個東西對生命來說是不可或缺的。

The universal needs for life are good ol' carbon and water.

宇宙的萬物都需要好的氧氣和水。

Life is basically organized chemistry.

生命基本上就是有組織的化學。

Inside every cell on Earth, the making and breaking of bonds, building cellular machinery,

在地球上所有的細胞裡，鍵結的形成和破壞、細胞結構的建立、

copying DNA, even the membranes that keep a cell from spilling its guts… all depend

DNA 的複製、甚至是防止胞器跑出細胞的細胞膜都仰賴

on liquid H2O.

液態水。

But salty environments, frozen environments, or low-pressure atmospheres lack usable H2O,

但是鹹的、冰凍的或是低氣壓的環境缺乏可以使用的水，

they're essentially as dry as deserts.

它們基本上跟沙漠一樣乾。

Yet, in places like super-dry Antarctica, and deep in hidden caves, we find microbes,

不過，我們在像是南極一樣很乾燥的地方和洞穴的底部都有找到微生物，

tucked away *inside* rocks and crystals, where they've carved out tiny water-filled pocket little

它們隱藏在石頭和水晶裡面，它們會雕出細小的洞，這些洞裡充滿著水，像是

microscopic oases in deserts made of stone and salt.

沙漠裡由石頭和鹽所製造出的小綠洲。

In places like Chile's Atacama desert, one of the driest places on Earth, microbes pluck

在像是智利的阿塔卡馬沙漠，地球上其中一個最乾燥的地方裡，微生物會直接拿

water molecules right from the air, and make their own liquid shells.

空氣中的水分子來製作一個液態外殼。

On a planet like Venus, where it's just too darn hot for water to remain liquid at

在像是金星的星球上，當表面溫度已經太熱，水不可能維持液態的時候，

the surface--microbial life could be suspended in tiny droplets of water in the upper atmosphere.

微生物可以懸浮在地表上層空氣中的小水滴中。

One of the biggest risks to life anywhere is dangerous radiation: UV, gamma rays, and

不論在哪裡，生命其中一個最大的威脅是危險的輻射，例如紫外線、伽瑪射線和

X-rays, which can damage cells and mutate DNA.

X 光，它們可以摧毀細胞和造成 DNA 突變。

We don't worry about it much here because our magnetic field protects us, but elsewhere

因為磁場會保護我們所以我們不太擔心這些，但是在其他的地方

life would either be forced to shield itself underground or else figure out how to put

生命會被迫於躲到地底下或是尋找一個

up with a daily dose of mutation.

可以每天承受突變的方法。

Microbes seem to have this figured out too.

微生物似乎已經找到了方法。

In places like Chernobyl, we've found bacteria that can withstand huge doses of radiation.

在像是切爾諾貝利的地方，我們找到了可以經得住大量輻射的細菌。

Even cockroaches can handle at least 100 times more ionizing radiation than humans can, although

甚至是蟑螂可以承受的游離輻射量都至少是人類的一百倍，儘管

this is surprising to no one.

這已經不值得驚訝。

If these extremes seem harsh, it's probably because animals like us have a very narrow

如果這些極端的環境在我們看來很嚴苛，這可能是因為像我們一樣的動物有著非常狹窄的

window of survival.

生存區間。

Life has existed on Earth for more than 3 billion years, and it's flip-flopped from

生命已經生活在地球上超過 30 億年了，而且地球已經在

super scorching to super snowball many times.

極度炎熱和冰冷之間變換過無數次。

Our extremes may have been normal to Earth's earliest inhabitants.

我們所認為惡劣的環境也許對早期棲居在地球的生物來說是正常的。

Even our oxygen-rich atmosphere would be considered extreme to some life forms.

高氧的空氣甚至對某些生物來說也是惡劣的環境。

There's a good chance the first lifeforms were similar to what Woese discovered at those

有很大的可能初始的生命跟 Woose 在加拉帕戈斯底下

boiling black smokers beneath the Galapagos.

的深海熱泉中找到的很相似。

Understanding how life survives our extremes broadens our horizons for where we think life

了解生命如何在惡劣的環境中生存會幫助我們更加了解生命

can exist--and tells us where to look beyond Earth.

可以存在的地方，並告訴我們在地球以外可以關注的地方。

So far, we've only found life in one place, but if the odds of sharing this galaxy with

目前為止，我們只在一個地方找到生命，但是如果與另一個星球分享這個銀河系

another living planet ever seem too extreme, just remember that life, uh, finds a way.

的可能性似乎過於極端，你只要記得生命會自己找到出路。

Stay curious.

保持好奇。