What the Discovery of Exoplanets Reveals About the Universe | Jessie Christiansen | TED

翻译人员: Yip Yan Yeung 校对人员: Yan Li Xiao

I am a planet hunter

我是个行星猎人，

and keeper of the keys at NASA's Exoplanet Archive.

也是 NASA（美国航空航天局） 系外行星档案的钥匙保管人。

In March 2022, we reached a major milestone in space exploration:

2022 年 3 月，我们达成了 太空探索的一个重要成就：

5,000 known exoplanets.

5000 个已知系外行星。

For thousands of years,

几千年以来，

we've wondered about planets outside of our solar system,

我们都想了解 太阳系以外的行星，

now called exoplanets.

如今被称为“系外行星”。

But our technology only recently caught up with our imaginations.

但是直到最近，我们的科技 才赶上了我们的想象。

And yes, 5,000 planets is incredible.

没错，5000 颗行星 是个惊人的数目。

What's even more incredible

更惊人的是

is how space research will change as a result.

它为太空研究带来的改变。

When I started grad school,

我开始读研究生时，

there were about 100 known exoplanets,

大约有 100 个已知系外行星，

all radically different from the Earth and from each other.

全部与地球大相径庭， 各不相同。

I was determined to find more.

我下定决心要找出更多。

I spent four years looking at nearly 87,000 stars, one by one.

我花了四年，逐一观察 87000 颗恒星。

Now you might have this romantic idea

你可能会脑补 这样一个浪漫的场景，

that I was gazing intently through a telescope,

我专心致志地 透过望远镜凝视星空，

pondering some gorgeous view of the universe.

徜徉在宇宙的美景中。

I was not.

并不是。

I was looking at data like this,

我看的是这种数据，

measuring the brightness of each star over time.

持续测量每颗恒星的亮度。

If the brightness dipped, just briefly, just a little bit,

如果亮度降低，即使是一瞬， 即使是少许，

it could be because a planet had orbited in front of that star,

都有可能是因为有一颗行星 运行到了这颗恒星前方，

blocking some of the light from reaching my telescope.

挡住了射向望远镜的部分光线。

So I spent four years looking for decimal-level changes in these data.

我花了四年寻找数据中 微乎其微的变化。

And after four years, I'd found ...

过了四年，我发现了……

nothing.

啥都没发现。

Zero exoplanets.

0 个系外行星。

Thankfully, they still gave me the PhD, I think, for effort.

好在他们还是给了我博士学位。 我猜是因为没有功劳也有苦劳。

(Laughter)

（笑声）

Then I moved to Harvard, where I worked on my first NASA mission, called EPOXI.

然后我去了哈佛，开始了我的第一个 NASA 任务，名为 EPOXI。

I still didn't find any exoplanets.

我还是没发现任何系外行星。

Then in March 2010, I joined the Kepler Mission,

2010 年 3 月， 我加入了开普勒任务，

NASA's grand experiment

NASA 的一个重大任务，

with putting one of our planet-hunting instruments into space.

将一台探索行星的仪器 发射进太空。

Monday was my first day on the base in Silicon Valley.

星期一是我进入硅谷基地 工作的第一天。

It was mostly spent in HR.

基本上都在处理人事手续。

Tuesday, I sat down and looked at the data for the first time,

星期二，我第一次坐下查看了数据，

and I found my first exoplanet.

就找到了我的第一颗系外行星。

(Cheers)

（欢呼声）

(Applause)

（掌声）

A few minutes later, I found another one.

几分钟后，我又找到了一颗。

There's a saying that we're the generation that was born too late to explore Earth

有人说，我们这一代人， 探索地球为时已晚，

and too soon to explore space.

探索太空为时尚早。

That's not true anymore.

这种说法已经过时了。

That day and every day since, I've gotten to explore space.

那一天及自此的每一天， 我都在探索太空。

Kepler made it possible for us

开普勒让我们可以

to measure stellar brightness much more precisely

以前所未有的精度 测量恒星亮度。

than we had before.

And eventually I helped find thousands of exoplanets.

我最终得以参与发现 几千个系外行星。

And we've really only searched our local corner of the galaxy

而且我们只搜索了 银河系里我们眼前的一隅，

to find those planets.

就发现了这些系外行星。

That means there's likely tens of billions of planets just in our Milky Way.

意味着仅仅在我们的银河系中， 就有可能存在几百亿颗行星。

Now with so much data,

有了这么多数据，

we can start sorting and grouping and categorizing these planets

我们开始整理、 合并、分类这些行星，

to find trends.

寻找趋势。

Think of it this way:

可以这么理解：

if you wanted to learn about dogs and you had five dogs in your study,

如果你想了解狗， 你的研究中包含了五条狗，

well, you'd learn a lot about those five dogs.

那你就能充分了解 这五条狗的情况。

That they're all good dogs.

了解到它们都是好狗。

But maybe not about dogs in general.

但是你可能无法得出 狗的宏观情况。

If you had 5,000 dogs in your study,

如果研究包含了五千条狗，

then you’d start to see that there were German Shepherds and Dobermanns

你就能看出其中有 德国牧羊犬、杜宾犬、

and beagles,

比格犬，

and that these different breeds have different features.

每个品种都有不同的特点。

With demographic-level data on exoplanets,

有了系外行星 具体特征的数据，

we can start asking some of these big questions for the first time,

我们终于能问出一些 更宏大的问题，

like: Of those thousands and billions of planets in our galaxy,

比如：在银河系 这上亿的行星中，

how many are like the Earth, or like Jupiter?

有多少个类似地球，类似木星？

How many planets does a typical star have?

一颗恒星通常有多少颗行星？

Can a planet orbit more than one star?

行星能否围绕不止一颗恒星运行？

Yes.

可以。

Can a planet exist without any star at all?

不依靠恒星，行星还能存在吗？

Also yes.

答案也是可以。

One surprising result from the study of planet populations

行星样本研究 带来了一个惊人的结果：

is that the most common kind of planet in our galaxy

我们银河系中最常见的一种行星

might be one we don’t have in our solar system:

可能是我们的太阳系中 不存在的一种行星——

a super-Earth up to twice as big and ten times as heavy as our Earth.

地球两倍大、 十倍重的超级地球。

We've found evaporating planets, disintegrating planets,

我们还发现了蒸发行星、 解体行星、

planets clustered together in a clockwork dance,

以机械运转形态 聚在一起的行星、

ultra-puffy planets, ultra-dense planets.

过度膨胀的行星、 过度紧缩的行星。

It's truly a wild and wonderful menagerie

在我打开 NASA 系外行星档案的栅栏时，

that I get to corral at the NASA Exoplanet Archive.

涌向我的是无拘无束、 无与伦比的自由生命。

But it gets even more interesting than that.

但是有意思的地方不止于此。

With so much data, we might finally be able

手握这么多数据，我们终于

to figure out how planets are made.

有机会搞明白行星的起源了。

We see baby stars being born in stellar nurseries

我们知道原恒星诞生于 充满宇宙尘埃和气体的恒星摇篮。

surrounded by dust and gas.

And we see all the stars surrounded by completed planetary systems.

我们也知道所有恒星 都由完全形成的行星系统环绕。

But we still don't really know what happens in between.

但是我们依旧不知道 这之间发生了什么。

With more data, we might find planets

如果有了更多的数据， 我们就有可能发现

at some middle stage or many middle stages.

处在某个或某些中间阶段的行星。

And from there, be able to map out a timeline of planetary development.

接着我们就能描绘出 行星演变的整个过程。

What triggers these diffused clouds of dust and gas to collapse and transform?

是什么导致了这些四处弥漫的 尘埃和气体团分解、变形？

And how does the chaos and turmoil of dust become pebbles,

尘埃是如何经过风云巨变 变成卵石的，

and pebbles become boulders, and boulders become planetesimals?

卵石是如何变成巨石的， 巨石是如何变成星子的？

And from there,

紧接着，

after an intense series of bombardments

在一系列猛烈的撞击之后，

eventually settle into an ordered series of planets.

最终形成了有序的行星。

How often is one of those planets solid and warm,

有多少概率出现一个 坚固、温暖的行星，

with a water ocean lapping a sandy shore?

还有液体海洋 拍打着沙质海岸呢？

Where do we come from, and how did we get here?

我们从哪里来， 我们又是怎么来的呢？

The more we learn about exoplanets,

我们越了解系外行星，

the easier it is to target the ones we want.

就越容易找到我们想要的目标。

So far, we haven't found any planets that are like the Earth.

直至目前，我们还没有发现 任何类似于地球的行星。

But I hope we will.

但是我希望我们能发现。

NASA just spent the last few years

NASA 在过去的几年里，

studying the idea of a very large telescope in space

一直在研究超巨型太空望远镜，

with next-generation technology that would allow us to take an image,

搭载新一代技术， 让我们能够拍下一张照片，

an actual photograph, of a planet like the Earth.

为类似地球的行星 拍下一张真实的照片。

With that photo, we could search for biomarkers, signatures of life.

有了这张照片，我们就能 探索生物标记物，即生命的迹象。

I'll probably spend the rest of my career working on that mission.

我也许会将我余下的职业生涯 奉献给这个任务。

I hope I get to take that photo.

我希望我能拍到这张照片。

Thank you.

谢谢。

(Applause)

（掌声）