Sarah Rugheimer: The search for microscopic aliens | TED Fellows

翻译人员: 校对人员: Helen Chang

[SHAPE YOUR FUTURE]

【塑造你的未来】

I want to find aliens.

我想寻找外星人。

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

在另一个星球上 寻找生物不会那么简单，

it's going to be very hard.

它会非常困难。

But for the first time in human history,

但这是在人类历史中的第一次，

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

我们有机会探测到 另一个星球上的生物迹象。

Or maybe we've already detected it on Venus.

也许我们早已在金星上 探测到外星人了。

Or maybe not.

也许我们还没有。

There are still two big hurdles

当涉及到确认另一个星球上的生物，

when it comes to confirming life on another world.

我们仍面临着两个巨大的障碍。

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

第一个障碍是 如何造出足够大的望远镜，

and the second is interpreting what we will find.

第二个障碍是 解读我们要找的究竟是什么。

When we think of extraterrestrial life,

当我们想到外星生物时，

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

我们倾向于把它们想象成 有趣的小绿人，

not aliens as single-celled microbes.

而不是单细胞微生物。

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

但实际上我最看好的就是 探测另一个星球上的微生物生命迹象，

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

这也是我的主要研究方向。

I model how a star's high-energy radiation

我模拟了恒星的高能辐射

can make gases from microbes harder or easier to see

如何使来自微生物的气体 在未来的望远镜中

with future telescopes.

更难或更易被观察到。

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

在地球的大部分历史上， 微生物都统治着我们星球的生物圈。

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

它们持续释放着 能在大气中被看到的气体，

even light years away --

在光年之外，

for billions of years.

在数十亿年间。

Now, if an alien astronomer were looking at Earth,

如果一个外星天文学家 现在正在看地球，

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

它也许会先探测到氧气、甲烷、 一氧化二氮之类的气体，

before detecting signs of us.

然后才探测到我们的迹象。

Even with an active biosphere like Earth's,

即便有像地球一样的活跃的生物圈，

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

大部分表示生物的气体 也来自于单细胞生物，

not from animals.

而不是来自于动物。

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

这是我们天文学下一个十年的目标，

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

试图在围绕其他恒星运转的行星上 找到微生物的迹象。

But the technology to detect the atmosphere

但是想要探测到

of a planet the size of Earth

一个地球大小的

around another sun

围绕着另一个太阳的的行星的大气，

is incredibly difficult.

从技术上来说是十分困难的。

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

这就像是试图在聚光灯前 确定一只萤火虫大小，

while looking from another continent.

而且还是从另一片大陆上去观察。

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

令人惊奇的是， 在21世纪20年代望远镜的帮助下，

we're overcoming this technological barrier.

我们正在克服这项科技障碍。

The second issue defining alien life

第二个问题，界定外星生物，

will be to interpret what these biosignature gases actually mean.

也就是解释这些 生物信号气体的实际含义。

Twenty-one percent of our atmosphere is oxygen,

我们的大气层中有21%是氧气，

and nearly all of that oxygen comes from life.

而且几乎所有氧气都来自于生物。

So here's the tricky question:

因此，这里有个棘手的问题：

Would detecting oxygen on another planet mean life?

探测到另一个星球上有氧气 是不是就意味着那里有生物呢？

No, not necessarily,

不，那并不一定。

because we know of ways to get oxygen without biology.

因为我们知道 如何在没有生物的情况下获得氧气。

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

我得了解一颗行星的地质 和它恒星的辐射，

so that we can better identify a true life signal.

才能更好地识别出真正的生物信号。

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

这就让在金星上初步探测到的磷化氢，

a potential biosignature gas,

一种可能的生物信号气体，

so compelling but also so confusing.

那么令人信服，也那么令人困惑。

Venus is not where we expected to find life.

我们并没有期待在金星上找到生物。

It is a hellish world,

金星是个环境恶劣的地方，

with a surface temperature of nearly 900 degrees Fahrenheit.

它的表面温度有将近900华氏度。

Could life be floating in the more temperate upper atmosphere?

生物可以漂浮在较温和的 上层大气上吗？

But then how would such life eat and reproduce?

这样的生物又怎么进食并且繁殖呢？

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

这一发现将会在未来十年内被检验。

First, we must verify the detection of phosphine itself,

首先，我们必须验证磷化氢本身，

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

随后，我们得确认 这种气体确实来自于生物，

and not from some unexpected geological or photochemical process.

而不是来自于一些 意想不到的地质或者光化学过程，

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

如果它确实来自于生物，

那这将是我们这代人 最具影响力的发现之一。

If it turns out that we were fooled,

如果事实证明，我们搞错了，

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

我们错以为这种气体来自生物， 实际上它产生于其他过程，

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

我们将会受到一个令人清醒的教训， 并将它运用在围绕遥远恒星的行星上。

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

金星离我们很近， 可以说是我们的隔壁邻居。

and yet we still have trouble understanding it.

我们却仍难以理解它。

The planets we're finding orbiting other stars

那些围绕着其他恒星的行星，

are weird and unexpected.

都是怪异且出人意料的。

Some have the density of cotton candy,

有些行星的密度和棉花糖一样，

and others rain molten iron.

有些则会下铁雨。

And most stars are different from our sun,

而且大部分恒星都和太阳不同，

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

它们的高能耀斑使得生物很难生存。

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

所以我们越是研究生物信号气体，

the more we realize that there's no single gas

就会越发意识到， 没有任何一种单一的气体

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

足以让我们了解一颗行星， 并声称上面有外星生物。

It is just really difficult to distinguish life from nonlife

要在光年之外区分生物和非生物，

from light years away.

实在是太难了。

And here's where the ambiguity lies.

而这正是模糊不清的地方。

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

我们要如何判断 一个线索是不是生物的迹象呢？

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

首先，我们需要尽可能多地了解

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

一颗行星的地质情况和它围绕的恒星。

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

我们会通过在金星和火星等地

in places such as Venus and Mars.

探索我们的太阳系来学习宝贵的经验。

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

我们在宇宙中是不是孤单的？ 我们距离解开这个人类最大谜题，

Are we alone in the universe?

已经越来越近了。

Any claim will be hotly debated.

任何主张都会引起激烈的争论。

So basically, I'm stretched between two desires.

所以基本上，我在两个愿望间挣扎。

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

我想找到外星生物， 但我可能不会得到一个明确的答案。

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

这可以接受。 毕竟科学是微妙且会自动修正的。

It's what I love about it.

这也是我热爱科学的原因。

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

科学就是要平衡 其怀疑主义和希望的双重性。

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

我们不能把自己传输到另一个星球上

and take pictures of alien kangaroos jumping around.

并拍摄外星袋鼠跳来跳去的照片。

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

如果无法接收到类似于 ”你好，地球人！“的智慧信号，

we might still feel lonely,

即便我们发现 我们在宇宙中不是孤单的，

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

我们也许仍会感到孤独。

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

尽管存在这些挑战， 我仍然对外星微生物

and what they could teach us.

以及它能教会我们的东西 感到非常期待。

Even if we find just one other sign of life,

即便我们只发现一个其他的生物迹象，

then likely the universe is teeming with it,

那么宇宙也有可能充满了

from single-celled to complex.

从单细胞到复杂的各种生物。

If we search for decades and find nothing,

如果我们寻找了几十年却一无所获，

then that is equally humbling.

那这同样是令人羞愧的。

But we must try.

但我们必须尝试。

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

我们必须进行这种探索， 即便这意味着沿途的不确定性。

Thank you.

谢谢。