One of my lifelong goals is to find an Earth-sized planet in an Earth-like orbit about a sun-like star.
我毕生的目标之一是在类似地球运行的轨道上围绕类似太阳的恒星找到一颗地球大小的行星。
One that has a thin atmosphere, and that has water oceans.
这颗行星上大气稀薄，有海水。
One where we can point to a specific star and say that star has a planet like Earth.
在那里，我们可以指向一颗特定的恒星，并说该恒星周围有一颗类似地球的行星。
What I love to dream about is maybe there's some life on that planet you know, looking back at our Earth and our star and saying the same thing.
我喜欢幻想也许那颗行星上有生命，他们回头看向我们的地球和恒星，会说同样的话。
Like how amazing would that be?
那会有多神奇？
It would be amazing.
那太神奇了。
Now, this idea - that the stars have planets of their own and that those planets might have aliens living on them has been around for centuries.
现在，这种想法，即恒星有自己的行星，这些行星上可能有外星人居住，已经存在了几个世纪。
At first it had some pretty harsh critics.
起初，这种想法受到了一些非常严厉的批评。
But by 20th century, it was mainstream.
但到了20世纪，这种想法已成为主流。
Alien worlds showed up in books and then movies and TV.
外星世界出现在书籍、电影和电视中。
"In this galaxy, there's a mathematical probability of three million Earth-type planets".
"在银河系里，理论上可能有300万颗地球这样的行星"。
But here's the thing - even after all that, even when this episode of Star Trek: The Next Generation aired in 1987 scientists still hadn't confirmed the existence of a single planet outside our solar system.
但事情却是这样的——即使1987年播出了《星际迷航：下一代》，但科学家们仍然没有证实太阳系外存在着行星。
For all we knew, these so-called "exoplanets" could only be found in fiction.
据我们所知，所谓的"系外行星"只存在于小说中。
But the next generation of astronomers, armed with new telescopes and more powerful computers, set out to change that.
但是下一代装备了新型望远镜和功能更强大的计算机的天文学家开始改变这种状况。
This is Sara Seager.
这是Sara Seager。
She's a professor of astrophysics at MIT.
她是麻省理工学院的天体物理学教授。
It's the spirit of us being the first explorers, you know.
这是我们作为第一批探险家所具备的勇气。
We get to see what's out there for the very first time.
我们第一次看到外面的景象。 ~eudic
We get to know if there are other planets like ours.
我们可以知道是否还有其他类似地球的行星。
Here's a map of what they've found so far: It's our night sky, which is a sphere projected onto this square map.
这是一张标记着他们迄今为止发现的地图：这是我们的球形夜空，它投影到了这张正方形的地图上。
It's sort of one of the maps of the world, it's like, well, obviously we're on a globe, but this is all stretched out.
这有点像是世界地图，很明显我们处在球体上，但这个球体完全展开了。
Exactly, it's all stretched out.
是的，完全展开了。
The black dots are visible stars with the North Star, Polaris up here at the top of the map.
黑点是可见的恒星，北极星在地图的顶部。 倩言
And this band is the densest part of our own Milky Way Galaxy.
这条带是银河系中恒星最密集的部分。
The lines trace out constellations.
这些线条勾勒出星群。
So we can look for a familiar constellation like the Big Dipper. Up here. And here's Orion, actually.
我们可以找到一个熟悉的星群，比如北斗七星。在这里。这是猎户座。
And these colorful dots mark the position of stars with known "exoplanets".
这些彩色圆点标记了环绕着已知"系外行星"的恒星的位置。
The very first exoplanet around a sun-like star wasn't discovered until 1995. It was called 51 Pegasi b.
直到1995年，第一颗环绕类似太阳的恒星运行的系外行星才被发现。它叫做飞马座51b。
