Name: 我們可能在 2089 天后發現外星生命 (We Might Find Alien Life In 2089 Days)
Uploaded: 2025-07-10T05:18:43.000Z
Duration: 17 min 55 s

Clarke had a sequel to 2001 A Space Odyssey.

克拉克曾為《2001太空漫遊》寫過續集。

It's called 2010 Odyssey 2, and at the end of it, an alien intelligence converts Jupiter into a star.

它的名字叫《2010 奧德賽 2》，在它的結尾，一個外星智慧生物把木星變成了一顆恆星。

As a group of astronauts narrowly escape the implosion, they receive the following message from the aliens.

當一群太空人勉強躲過內爆之後，他們收到了外星人發來的以下資訊。

All these worlds are yours, except Europa.

除了歐羅巴之外，所有這些世界都是你們的。

No, but it suggests that already in 1982, we suspected that Europa might offer our best chance of finding alien life in our solar system.

不，但它表明，早在1982年，我們就懷疑木衛二可能是我們在太陽系中發現外星生命的最佳機會。

Forty-two years later, in October 2024, NASA is actually launching the most advanced mission to hunt for signs of alien life, and it's going to Jupiter's moon, Europa.

42 年後的 2024 年 10 月，美國國家航空航天局（NASA）將啟動最先進的任務，前往木星的衛星木衛二尋找外星生命的跡象。

那麼，那裡怎麼會有生命存在呢？

And how do you make a probe that can withstand the perilous conditions?

怎樣才能製造出能夠承受危險條件的探測器呢？

Deep inside Jupiter, there is so much pressure that hydrogen is believed to take the form of a metallic liquid.

在木星深處，壓力非常大，據說氫是以金屬液體的形式存在的。

And this metallic liquid hydrogen generates an incredibly powerful magnetic field, almost 20,000 times stronger than Earth, if you measure at the same distance away.

而這種金屬液態氫會產生無比強大的磁場，如果在同樣的距離測量，其磁場強度幾乎是地球的 2 萬倍。

So if you could see this magnetic field from Earth, it would appear twice as big as the full moon.

是以，如果你能從地球上看到這個磁場，它看起來會比滿月大一倍。

On its own, that magnetic field is harmless, but right in the middle of it is the most volcanically active world in the solar system, Jupiter's moon, Io.

就磁場本身而言，它是無害的，但就在磁場中間的是太陽系中火山最活躍的世界--木星的衛星木衛一。

The volcanoes on Io's surface shoot out tons of sulfur dioxide, and every second, one ton of this material gets ionized and trapped inside Jupiter's magnetic field.

木衛二表面的火山噴射出成噸的二氧化硫，每秒鐘就有一噸二氧化硫被電離並被困在木星的磁場中。

And the field accelerates these particles to rotate incredibly fast with Jupiter, so they whiz around at over 300 kilometers per second.

這個磁場加速了這些粒子，使它們以難以置信的速度隨木星旋轉，是以它們以每秒 300 多公里的速度呼嘯而過。

Their inertia actually pulls back on the field, stretching it out, and this trapped material slams into other moons, ejecting even more particles from their surfaces.

它們的慣性實際上拉回了場，將其拉長，這些被困住的物質撞向其他衛星，從它們的表面噴射出更多的粒子。

This cycle forms massive radiation belts which span past Europa and the other moons of Jupiter.

這個週期形成了巨大的輻射帶，穿過木衛二和木星的其他衛星。

Now for electronics, this intense radiation is kryptonite.

現在，對於電子設備來說，這種強烈的輻射就是氪石。

In the 1970s, the Pioneer 10 and Voyager missions only briefly passed by Jupiter.

20 世紀 70 年代，"先驅者 10 號 "和 "旅行者號 "飛行任務只是短暫地經過木星。

But the radiation caused glitches, gave the instruments false commands, and corrupted some of their data.

但輻射造成了故障，給儀器帶來了錯誤的指令，並破壞了部分數據。

Even with modern shielding, a spacecraft within the radiation belts would only survive for around three months.

即使有現代屏蔽裝置，輻射帶內的航天器也只能存活三個月左右。

So how will NASA's new mission, the Europa Clipper, orbit Europa for over four years without getting fried?

那麼，美國宇航局的新任務 "歐羅巴快船 "將如何繞歐羅巴運行四年多而不被燒燬呢？

It'll orbit Jupiter from afar and then swoop in every few weeks to quickly fly by Europa and then leave again.

它將從遠處繞木星運行，然後每隔幾周俯衝一次，快速飛過木衛二，然後再次離開。

And since the mission is going to collect a lot of data, it can use the downtime while it's way out here to transmit it all back to Earth before going in for another swoop.

由於這次任務要收集大量數據，它可以利用在這裡的停機時間，將所有數據傳回地球，然後再進行下一次飛行。

In all, it'll do 49 flybys, mapping almost the entire surface.

它總共將進行 49 次飛越，繪製幾乎整個地表的地圖。

That's actually how the Clipper got its name, after the fast and nimble 19th century clipper ships quickly dipping in and out of ports.

事實上，這就是 "快船號 "名稱的由來，因為 19 世紀的 "快船號 "快速、靈活地進出港口。

But of all the places in the solar system to look for life, why Europa?

但是，在太陽系中那麼多可以尋找生命的地方，為什麼偏偏是木衛二呢？

If you stood on Europa's surface, you'd be hit with 5,400 millisieverts of radiation in a single day.

如果你站在歐羅巴表面，一天之內就會受到 5400 毫西弗的輻射。

That's 1,800 times more than the annual dose here on Earth.

這比地球上的年劑量高出 1800 倍。

If you stay here for a couple hours, you would eventually die from radiation sickness.

如果你在這裡呆上幾個小時，最終就會死於輻射病。

When Voyager 1 passed by Jupiter in 1979, it took this photo of Europa.

1979 年旅行者 1 號經過木星時，拍攝了這張木衛二照片。

If you compare that to most of the other moons in the solar system, you'll notice something is missing.

如果把它與太陽系中的大多數其他衛星相比，你會發現少了點什麼。

Every planet and moon has been bombarded by asteroids over billions of years, and most planetary surfaces show it.

數十億年來，每一顆行星和月球都受到過小行星的轟擊，大多數行星的表面都有這種痕跡。

Well, something recent, say over the past 60 million years or so, must have been happening on Europa to erase most of these craters from the surface.

那麼，歐羅巴星上一定是最近發生了什麼，比如說在過去的6000萬年左右，才把這些環形山從表面上大部分抹去。

Sixteen years after Voyager, Galileo arrived to Jupiter.

旅行者號16年後，伽利略號抵達木星。

It spent eight years studying both the gas giant and its moons.

它花了八年時間研究這顆氣態巨行星及其衛星。

And Galileo's magnetometer picked up something interesting on Europa.

伽利略的磁力計在歐羅巴上發現了一些有趣的東西。

Jupiter's magnetic poles, like Earth's, aren't aligned with its geographic poles.

木星的磁極和地球的磁極一樣，並不與其地理極點對齊。

So as the planet rotates every 10 hours, the whole magnetic field wobbles.

是以，當行星每 10 個小時自轉一次時，整個磁場就會擺動一次。

This changing field from Jupiter induces a magnetic field on Europa, and a relatively strong one at that.

木星不斷變化的磁場在木衛二上形成了一個磁場，而且是一個相對較強的磁場。

That means there must be an electrically conductive layer within Europa that reacts to Jupiter's  And readings from Galileo indicate that it must be somewhere close to the surface, only tens of kilometers deep.

這意味著木衛二內部一定有一個導電層會對木星產生反應，而伽利略號的讀數表明，這個導電層一定在靠近表面的地方，只有幾十公里深。

Well, Europa's white surface is almost entirely covered in a thick crust of water ice.

歐羅巴的白色表面幾乎完全被厚厚的水冰層覆蓋。

These reddish-brown regions, when observed through a spectrometer, fit the description of a lot of things, like hydrated salts, sulfuric acid, or even bacteria.

通過光譜儀觀察，這些紅褐色區域符合很多東西的描述，比如水合鹽、硫酸，甚至細菌。

We need more data to be sure, but recent experiments at JPL found that sea salt, when bombarded with intense radiation, turns from white to this same brownish color found on Europa.

我們需要更多的數據才能確定，但 JPL 最近的實驗發現，海鹽在受到強烈輻射轟擊後，會從白色變成歐羅巴上發現的這種褐色。

So scientists suspect that there's a whole saltwater ocean inside Europa that could be 100 kilometers deep, meaning Europa would contain twice as much water as the whole of the Earth.

是以，科學家們懷疑木衛二內部有一整片鹽水海洋，可能有100公里深，這意味著木衛二的含水量是整個地球的兩倍。

And it must be driving geological activity that constantly smooths out and renews the surface of the moon.

它一定在推動地質活動，使月球表面不斷平滑和更新。

But the Jupiter system only gets about 4% of the sunlight we get here on Earth.

但木星系統獲得的陽光只有我們地球上的 4%。

So Europa's surface is constantly below negative 160 degrees Celsius, so you'd expect the whole ocean to be frozen solid.

是以，歐羅巴表面的溫度常年低於負160攝氏度，所以你會認為整個海洋都被凍得結結實實。

But there's a way to generate heat that doesn't rely on the sun.

但有一種不依賴太陽的制熱方法。

And I've got a little demo here to prove it.

我有一個小樣可以證明這一點。

Europa's orbit around Jupiter isn't a perfect circle.

木衛二圍繞木星的軌道並不是一個完美的圓。

This is because Io, Europa, and Ganymede are all in orbital resonance.

這是因為木衛一、木衛二和木衛三都處於軌道共振狀態。

Each time Ganymede completes one orbit, Europa completes two, and Io four.

每次木衛三完成一個軌道，木衛二完成兩個軌道，木衛四完成四個軌道。

Because of that, Io tugs Europa inward on one side of the orbit, while Ganymede pulls it out on the other, making its orbit more eccentric.

是以，木衛一在軌道的一側將歐羅巴向內拉扯，而木衛三則在另一側將其向外拉扯，使其軌道更加偏心。

Now Jupiter's pull is stronger on the closer side of the orbit than on the farther side.

現在，木星的拉力在軌道較近的一側比在較遠的一側更強。

So Europa is constantly being stretched and squeezed, stretched and squeezed.

是以，歐羅巴不斷受到拉伸和擠壓，拉伸和擠壓。

You can see how this rubber ball gets warmer as I squeeze it.

你可以看到這個橡膠球是如何隨著我的擠壓而變熱的。

Scientists believe that the friction caused by the tidal flexing of the entire moon can generate enough heat to keep the ocean liquid.

科學家認為，整個月球的潮汐彎曲所產生的摩擦力可以產生足夠的熱量，使海洋保持液態。

This effect gets stronger the closer you get to Jupiter, which is why Io is so volcanically active.

離木星越近，這種效應就越強，這也是木衛一火山如此活躍的原因。

So you can see this ball is significantly hotter now.

所以，你可以看到這個球現在明顯變熱了。

I held on to this ball at the same time to make sure it wasn't just the heat coming in from my hand.

我同時緊緊抓住這個球，以確保這不僅僅是我手上傳來的熱量。

What sort of temperature of the ocean are we thinking?

So melting temperature of ice, or maybe depressed by 10 degrees Celsius below that if it's a very salty ocean, similar to cold oceans on Earth.

是以，冰的融化溫度，如果是含鹽量很高的海洋，可能會比冰的融化溫度低 10 攝氏度，類似於地球上的寒冷海洋。

And how would the flexing differ if there's this big liquid ocean versus if there's no ocean there?

如果那裡有一個巨大的液態海洋和沒有海洋，彎曲會有什麼不同？

If there's no ocean, Europa should flex by only about one meter in amplitude.

如果沒有海洋，木衛二的彎曲幅度應該只有 1 米左右。

But if there's an ocean in there, then it flexes with an amplitude of 30 meters.

但如果那裡有一片海洋，那麼它的彎曲幅度就會達到 30 米。

And that will come out pretty clearly in the gravity data.

這一點在重力數據中會表現得非常明顯。

Another argument for how thick the ice shell is, we see these very strange features on the surface that are arcuate in shape, but like multiple arcs put together.

冰殼有多厚的另一個論據是，我們在表面看到了這些非常奇怪的特徵，它們呈弧形，但又像是多個弧形拼在一起的。

We call them cycloids, and it's not something you'd expect to see on an icy moon.

我們稱它們為環狀體，這可不是你能在冰冷的月球上看到的。

And we think they form if a crack propagates at just the right speed, about the speed someone would walk, and is following the changing stress field of Europa being squeezed as it orbits around Jupiter.

我們認為，如果裂縫的傳播速度恰到好處，就像人走路的速度一樣，並且隨著木衛二環繞木星運行時被擠壓的應力場的變化而變化，就會形成裂縫。

And if there were no ocean down there, there wouldn't be enough of an amplitude of that motion to explain the cracking.

如果下面沒有海洋，這種運動的振幅就不足以解釋開裂現象。

But if there is an ocean, then it could explain the cracking.

但是，如果存在海洋，那就可以解釋為什麼會出現裂縫。

All that tidal flexing pushes magma in the outer core up, closer to the seafloor.

所有的潮汐撓動都會將外核的岩漿推高，使其更接近海底。

Water flowing through the crust above it is heated and it picks up minerals from the ground, ejecting them into the ocean.

流經其上地殼的水被加熱，從地下吸附礦物質，並將其噴射到海洋中。

And where we find these on Earth, we also find life.

在地球上找到這些的地方，也就找到了生命。

Thousands of meters below the surface, with no sunlight, these vents are oases for ocean life.

這些噴口位於海面以下數千米處，沒有陽光，是海洋生物的綠洲。

The lifeforms down here rely on unique bacteria.

這裡的生命形式依賴於獨特的細菌。

Bacteria that feed on the minerals from the vents, rather than from the energy provided by the sun.

細菌以噴口中的礦物質為食，而不是以太陽提供的能量為食。

How long are we thinking that Europa has had an ocean?

我們認為歐羅巴擁有海洋的時間有多長？

That amount of time could give life the opportunity to evolve in those oceans.

這麼長的時間可以讓生命有機會在這些海洋中進化。

Organisms can use methane, carbon dioxide, sulfur reactions.

生物可利用甲烷、二氧化碳和硫發生反應。

Any chemical reaction you can think of that might happen in the ocean can potentially be used as a fuel for that organism's metabolism.

你能想到的任何可能在海洋中發生的化學反應，都有可能被用作生物新陳代謝的燃料。

So we're not talking about searching for fishes or whales or squids or something down there, but looking for single-celled organisms.

是以，我們不是在說尋找下面的魚類、鯨魚或魷魚什麼的，而是在尋找單細胞生物。

We were so concerned there might be life on Europa that when the Galileo mission was ending in 2003, it was deliberately crashed into Jupiter to avoid the risk of contaminating Europa.

我們非常擔心木衛二上可能存在生命，所以當伽利略號任務於2003年結束時，它被故意撞向木星，以避免汙染木衛二的風險。