Sarah Rugheimer: The search for microscopic aliens | TED Fellows

譯者: Wei-Yu Shih 審譯者: Helen Chang

[SHAPE YOUR FUTURE]

[塑造你的未來]

I want to find aliens.

我想要找到外星人。

Finding life on another planet is not just going to be a little hard,

要在另一顆星球上找到生命， 絕對不會只有一點難，

it's going to be very hard.

而是非常困難。

But for the first time in human history,

不過人類史上第一次

we have a chance to detect signs of life on another planet.

我們有機會探測到 另一個星球上的生命跡象。

Or maybe we've already detected it on Venus.

我們可能已經在金星上找到了。

Or maybe not.

或著其實沒有。

There are still two big hurdles

目前還有兩個很大的障礙，

when it comes to confirming life on another world.

如果要確認另一個世界的生命。

The first is building a telescope big enough to do this,

第一個是要做一個夠大的望遠鏡，

and the second is interpreting what we will find.

第二個則是理解我們的發現。

When we think of extraterrestrial life,

當我們想到外星生命，

we tend to think of aliens like funny little green men,

我們傾向於想像有趣的綠色外星人，

not aliens as single-celled microbes.

而不是外星的單細胞微生物。

But it's actually detecting signs of microbial life on another planet

但實際上探測在另一個星球上 微生物存活的跡象，

that I'm most optimistic about, and what I focus my research on.

是我覺得最有可能， 也是我專注在研究的。

I model how a star's high-energy radiation

我研究恆星的高能量輻射是如何

can make gases from microbes harder or easier to see

影響微生物產生氣體的可見度難易，

with future telescopes.

如果使用未來望遠鏡的話。

Microbes have dominated our planet's biosphere for most of Earth's history.

地球歷史上的大部分時間， 微生物主宰了我們星球的生物圈。

They've been emitting gases that can be seen in our atmosphere --

它們排出的氣體能夠在 我們的大氣中被看見，

even light years away --

就算是在數光年外，

for billions of years.

並持續了幾十億年。

Now, if an alien astronomer were looking at Earth,

假如一個外星的天文學家在觀察地球，

they would probably detect gases like oxygen, methane and nitrous oxide

他們可能會先探測到像是 氧氣、甲烷和一氧化二氮等氣體，

before detecting signs of us.

在發現我們存在的跡象之前。

Even with an active biosphere like Earth's,

就算地球擁有這般活躍的生物圈，

most of the gases that indicate life are coming from single-celled microbes,

大部分生命跡象氣體 都來自單細胞微生物，

not from animals.

而不是動物。

This is what we'll try to do in the next decade of astronomy --

天文學的下一個十年， 這就是我們打算要做的：

try to find signs of microbial life on planets orbiting other stars.

在其他行星系的星球上 尋找微生物的跡象。

But the technology to detect the atmosphere

但探測這種大氣的技術，

of a planet the size of Earth

對於與地球差不多大小

around another sun

並繞著另個太陽繞的星球，

is incredibly difficult.

是非常困難的。

It's like trying to determine the size of a firefly in front of a spotlight

就好比要判斷燈光下螢火蟲的大小，

while looking from another continent.

而且是從另一個洲看。

What's amazing is that with telescopes in the 2020s,

但令人驚喜的是， 2020年代的望遠鏡，

we're overcoming this technological barrier.

可以克服這個技術的障礙。

The second issue defining alien life

第二個定義外星生命的問題，

will be to interpret what these biosignature gases actually mean.

則是如何解釋生物特徵氣體的意義。

Twenty-one percent of our atmosphere is oxygen,

地球大氣中有百分之二十一的氧氣，

and nearly all of that oxygen comes from life.

而這些氧氣幾乎都來自於生物。

So here's the tricky question:

所以棘手問題來了：

Would detecting oxygen on another planet mean life?

在另一個星球發現氧氣， 是否等於發現生命？

No, not necessarily,

不是。不一定。

because we know of ways to get oxygen without biology.

因為我們知道沒有生物 也能產生氧氣的方法。

I try to understand a planet's geology and its star's radiation

我試著了解星球的地質 以及它恆星的輻射，

so that we can better identify a true life signal.

以讓我們更能確認真正的生命跡象。

And this is what makes the preliminary detection on Venus of phosphine,

這也就是為何在金星上 初步發現的磷化氫，

a potential biosignature gas,

一種潛在的生物特徵氣體，

so compelling but also so confusing.

引人注目的同時也很讓人疑惑。

Venus is not where we expected to find life.

金星並不是我們預期會有生命的地方。

It is a hellish world,

它的環境就像地獄，

with a surface temperature of nearly 900 degrees Fahrenheit.

地表溫度將近華氏九百度。

Could life be floating in the more temperate upper atmosphere?

還是生命可能漂浮在高大氣層？

But then how would such life eat and reproduce?

但這些生命要如何進食跟繁殖？

This discovery will have to be vetted over the coming decade.

這個發現會需要在 接下來的十年接受嚴格檢視。

First, we must verify the detection of phosphine itself,

第一，我們得確認發現磷化氫這件事。

and then later, we would have to confirm that this gas is coming from life

之後，我們要確定這氣體來自生命。

and not from some unexpected geological or photochemical process.

而不是意料之外的地質或光化學過程。

If true, this would be one of the most profound discoveries of our generation.

如果是真的，這將是我們這個世代 最重要的發現之一。

If it turns out that we were fooled,

假設我們錯了，

that we mistook this gas for biology when it's from some other process,

將此氣體誤會成與生物相關， 而實際上是透過其他方式產生的話，

we will have a sobering lesson to apply to planets orbiting distant stars.

會讓我們在研究更遙遠的 行星系時多一點省思。

Venus is close -- literally, our next-door neighbor --

金星很近，真的就是我們隔壁鄰居，

and yet we still have trouble understanding it.

但我們卻連了解它都有困難。

The planets we're finding orbiting other stars

我們發現的太陽系以外行星，

are weird and unexpected.

很奇怪並且出乎意料。

Some have the density of cotton candy,

有些的密度就像棉花糖，

and others rain molten iron.

有些則會下熔鐵的雨。

And most stars are different from our sun,

而且大部分恆星跟太陽不一樣，

with high-energy flares that can make it difficult for life.

高能量的火焰讓生命的存在很困難。

So the more we're looking at different biosignature gases,

所以當我們看越多 不同生物特徵氣體時，

the more we realize that there's no single gas

我們就更能意識到 沒有特定一種氣體，

that's enough to understand a planet and to claim alien life.

足夠讓我們了解一個星球 並且代表外星生物的存在。

It is just really difficult to distinguish life from nonlife

要區分生物與非生物很困難，

from light years away.

從數光年遠的地方。

And here's where the ambiguity lies.

這部分是個模糊地帶。

How will we know if a clue is a sign of life or is not?

我們要如何辨別一個線索 是否代表生命的跡象？

Well, first, we'll need to understand as much as we can

第一點，我們需要盡可能了解

about a planet's geology and the star it orbits.

一個星球的地質和它環繞的恆星。

We'll learn vital lessons by exploring our own solar system

我們可以藉由探索所在的太陽系 來更學習寶貴的經驗，

in places such as Venus and Mars.

例如金星跟火星。

We're getting closer to answering one of humanity's biggest questions:

我們距離人類最大問題之一的 解答越來越近：

Are we alone in the universe?

宇宙是否只有我們存在？

Any claim will be hotly debated.

任何一種主張都會被激烈的討論。

So basically, I'm stretched between two desires.

基本上，我渴望的有兩點。

I want to find alien life, but likely will not have a clear answer.

我希望能找到外星生物， 但可能不會有明確答案。

And that's OK; science is nuanced and self-correcting.

但沒關係，科學很微妙， 而且會自我修正。

It's what I love about it.

這就是為什麼我喜歡它。

Science is about balancing this duality of skepticism and of hope.

科學就是在懷疑與希望 兩者之間取得平衡。

We won't be able to teleport ourselves to another planet

我們無法瞬間移動到其他星球，

and take pictures of alien kangaroos jumping around.

然後把外星袋鼠 跳來跳去的樣子拍下來。

And without an intelligent "Hello, Earthlings!" signal,

在還沒收到「你好地球人」 的訊號之前，

we might still feel lonely,

我們可能還是會感到孤單，

even if we find out we're not alone in the universe.

就算我們發現自己在宇宙裡 並不是唯一的。

Despite these challenges, I'm super excited about alien microbes

儘管有這些挑戰， 我對於外星微生物還是很興奮，

and what they could teach us.

也很期待它們能教我們什麼。

Even if we find just one other sign of life,

就算我們只再找到一個 生命存在的證據，

then likely the universe is teeming with it,

那很有可能整個宇宙都充滿了生命，

from single-celled to complex.

從單細胞到更複雜的。

If we search for decades and find nothing,

如果我們花了數十年都沒找到，

then that is equally humbling.

這結果同樣令人謙卑。

But we must try.

但我們還是得嘗試。

We must do this search even when it means sitting with uncertainty along the way.

我們還是要繼續找尋， 就算沿路都充滿著不確定性。

Thank you.

謝謝。