TED精彩演讲 | 系外行星的发现揭示了宇宙的什么

I am a planet hunter and keeper of the keys at NASA's Exoplanet Archive. In March 2022, we reached a major milestone in space exploration: 5,000 known exoplanets. For thousands of years, we've wondered about planets outside of our solar system, now called exoplanets. But our technology only recently caught up with our imaginations. And yes, 5,000 planets is incredible. What's even more incredible is how space research will change as a result.

我是 NASA 系外行星档案馆的行星猎人和钥匙保管员。 2022 年 3 月，我们达到了太空探索的一个重要里程碑： 5,000 颗已知系外行星。 几千年来， 我们一直想知道太阳系外的行星， 现在称为系外行星。 但我们的技术最近才赶上了我们的想象力。 是的，5,000 颗行星令人难以置信。 更令人难以置信 的是，太空研究将因此发生怎样的变化。

When I started grad school, there were about 100 known exoplanets, all radically different from the Earth and from each other. I was determined to find more. I spent four years looking at nearly 87,000 stars, one by one. Now you might have this romantic idea that I was gazing intently through a telescope, pondering some gorgeous view of the universe. I was not. I was looking at data like this, measuring the brightness of each star over time. If the brightness dipped, just briefly, just a little bit, it could be because a planet had orbited in front of that star, blocking some of the light from reaching my telescope.

当我开始读研究生时， 大约有 100 颗已知的系外行星， 它们都与地球截然不同，彼此之间也截然不同。 我决心找到更多。 我花了四年时间，一颗一颗地观察了近 87,000 颗星星。 现在你可能会有这样一个浪漫的想法 ，那就是我正在通过望远镜专心凝视， 思考宇宙的一些壮丽景色。 我不是。 我正在查看这样的数据， 随时间测量每颗恒星的亮度。 如果亮度下降，只是短暂地下降一点点， 那可能是因为一颗行星在那颗恒星前面绕行， 阻挡了一些光线到达我的望远镜。

So I spent four years looking for decimal-level changes in these data. And after four years, I'd found ... nothing. Zero exoplanets. Thankfully, they still gave me the PhD, I think, for effort.

于是我花了四年时间寻找这些数据的小数位变化。 四年后，我发现…… 一无所获。 零系外行星。 值得庆幸的是，我认为他们仍然努力地给了我博士学位。

Then I moved to Harvard, where I worked on my first NASA mission, called EPOXI. I still didn't find any exoplanets. Then in March 2010, I joined the Kepler Mission, NASA's grand experiment with putting one of our planet-hunting instruments into space. Monday was my first day on the base in Silicon Valley. It was mostly spent in HR. Tuesday, I sat down and looked at the data for the first time, and I found my first exoplanet.

然后我搬到了哈佛，在那里我参与了我的第一个 NASA 任务，名为 EPOXI。 我仍然没有发现任何系外行星。 然后在 2010 年 3 月，我加入了开普勒任务，这是NASA 将我们的一种行星搜寻仪器送入太空的大型实验。 星期一是我在硅谷基地的第一天。它主要花在人力资源上。星期二，我第一次坐下来查看数据，发现了我的第一颗系外行星。

A few minutes later, I found another one. There's a saying that we're the generation that was born too late to explore Earth and too soon to explore space. That's not true anymore. That day and every day since, I've gotten to explore space. Kepler made it possible for us to measure stellar brightness much more precisely than we had before. And eventually I helped find thousands of exoplanets. And we've really only searched our local corner of the galaxy to find those planets. That means there's likely tens of billions of planets just in our Milky Way.

几分钟后，我又找到了一个。 有句话说，我们这一代人出生得太晚，无法探索地球 ，而太早无法探索太空。 这不再是真的了。 那天和之后的每一天，我都开始探索太空。 开普勒使我们 能够比以前更精确地测量恒星亮度 。 最终我帮助找到了数以千计的系外行星。 我们实际上只搜索了银河系的本地角落 来寻找这些行星。 这意味着我们的银河系中可能有数百亿颗行星。

Now with so much data, we can start sorting and grouping and categorizing these planets to find trends. Think of it this way: if you wanted to learn about dogs and you had five dogs in your study, well, you'd learn a lot about those five dogs. That they're all good dogs. But maybe not about dogs in general. If you had 5,000 dogs in your study, then you’d start to see that there were German Shepherds and Dobermanns and beagles, and that these different breeds have different features. With demographic-level data on exoplanets, we can start asking some of these big questions for the first time, like: Of those thousands and billions of planets in our galaxy, how many are like the Earth, or like Jupiter? How many planets does a typical star have? Can a planet orbit more than one star? Yes. Can a planet exist without any star at all? Also yes.

现在有了这么多数据， 我们可以开始对这些行星进行分类、分组和分类 ，以寻找趋势。 可以这样想： 如果你想了解狗，而你的研究中有五只狗 ，那么，你会对这五只狗了解很多。 他们都是好狗。 但也许不是一般的狗。 如果您的研究中有 5,000 只狗， 那么您会开始发现有德国牧羊犬、杜宾犬 和比格犬， 并且这些不同的品种具有不同的特征。 借助系外行星的人口统计数据， 我们可以首次开始提出其中一些重大问题， 例如：在我们银河系中的数千亿颗行星中， 有多少像地球，或像木星？ 一颗典型的恒星有多少颗行星？ 一颗行星可以绕多颗恒星运行吗？ 是的。 一颗行星可以完全没有任何恒星吗？ 也是的。

One surprising result from the study of planet populations is that the most common kind of planet in our galaxy might be one we don’t have in our solar system: a super-Earth up to twice as big and ten times as heavy as our Earth. We've found evaporating planets, disintegrating planets, planets clustered together in a clockwork dance, ultra-puffy planets, ultra-dense planets. It's truly a wild and wonderful menagerie that I get to corral at the NASA Exoplanet Archive. But it gets even more interesting than that. With so much data, we might finally be able to figure out how planets are made.

行星数量研究的一个令人惊讶的结果 是，我们银河系中最常见的行星类型 可能是我们太阳系中没有的行星： 一颗比地球大两倍、重十倍的超级地球. 我们发现了正在蒸发的行星、正在分解的行星、 以发条舞蹈的方式聚集在一起的 行星、超膨胀的行星、超致密的行星。 我在 NASA Exoplanet Archive收养的这真是一个狂野而美妙的动物园。 但它变得比这更有趣。有了如此多的数据，我们也许最终能够弄清楚行星是如何形成的。

We see baby stars being born in stellar nurseries surrounded by dust and gas. And we see all the stars surrounded by completed planetary systems. But we still don't really know what happens in between. With more data, we might find planets at some middle stage or many middle stages. And from there, be able to map out a timeline of planetary development. What triggers these diffused clouds of dust and gas to collapse and transform? And how does the chaos and turmoil of dust become pebbles, and pebbles become boulders, and boulders become planetesimals? And from there, after an intense series of bombardments eventually settle into an ordered series of planets. How often is one of those planets solid and warm, with a water ocean lapping a sandy shore? Where do we come from, and how did we get here?

我们看到婴儿恒星在 被尘埃和气体包围的恒星托儿所中诞生。 我们看到所有的恒星都被完整的行星系统包围着。 但我们仍然不知道这两者之间会发生什么。 有了更多的数据，我们可能会发现处于某个中间阶段或许多中间阶段的行星。 从那里，能够绘制出行星发展的时间表。是什么触发了这些扩散的尘埃和气体云坍塌和转变？尘埃的混乱和动荡如何变成鹅卵石，鹅卵石变成巨石，巨石变成星子？从那里开始，经过一系列激烈的轰击，最终形成一系列有序的行星。 这些行星中有多少次是固体和温暖的， 有海水覆盖着沙质海岸？ 我们从哪里来，又是如何到达这里的？

The more we learn about exoplanets, the easier it is to target the ones we want. So far, we haven't found any planets that are like the Earth. But I hope we will. NASA just spent the last few years studying the idea of a very large telescope in space with next-generation technology that would allow us to take an image, an actual photograph, of a planet like the Earth. With that photo, we could search for biomarkers, signatures of life. I'll probably spend the rest of my career working on that mission. I hope I get to take that photo.

我们对系外行星了解得越多，就越 容易找到我们想要的目标。 到目前为止，我们还没有发现任何像地球一样的行星。 但我希望我们会。 美国国家航空航天局在过去几年里刚刚研究了在太空 中使用下一代技术建立超大型望远镜的想法，该望远镜将使我们能够拍摄 像地球这样的行星的图像，即真实照片。有了那张照片，我们就可以搜索生物标志物，生命的特征。我可能会用余下的职业生涯来完成这项任务。我希望我能拍下那张照片。