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Hello and welcome to this episode of Tech Please!
大家好，欢迎来到本期的《科技脱口秀》！
This is Chenchen from Beijing and today we're joining the search for “Earth 2.0”.
我是晨辰，现在在北京的演播室，今天，让我们一起来寻找“地球2.0”。
So, “Earth 2.0”. You’ve all heard about that term?
所以，你们听说过“地球2.0”吗？
Well, let's talk about finding planets first.
我们先来讲一讲寻找行星吧。
To look for planets, NASA used to have the Kepler Space Telescope, and Europe has ESA’s Gaia, well, at least until 2025, which is its life expectancy.
为了寻找行星，美国国家航空航天局过去是通过开普勒望远镜进行观测，欧洲航天局用的是盖亚探测器，至少到2025年前这个望远镜都还可以坚持工作。
And remember the newly released deep field images of our universe captured by NASA's Webb telescope?
而且，记得前些日子NASA的韦伯望远镜发布的宇宙深空图吗？
Not only did they amaze us all, but we also learned that Webb will be used for collecting data about exoplanets, or extra-solar planets.
这不光让我们感慨万千，同时我们也得知，韦伯望远镜会被用来收集太阳系外行星的信息。
In fact, even before Webb, over 5,000 exoplanets had been discovered and confirmed by scientists, with around 50 Earth-like planets in the habitable zones.
事实上，在有韦伯望远镜以前，就已经有超过五千多系外行星被科学家们发现，其中，有大约50颗类地行星是位于宜居带内的。
Now, don't get excited too soon because most of them are hundreds of light-years away from Earth, meaning it could take us millions of years to travel there with our current fastest spacecraft.
但别高兴得太快，这些星球大部分都在地球的几百光年之外，也就是说，以我们现阶段最快的宇宙飞船也要花上百万年才能到达。
Now, with so many possibilities and unknows out there, China launched its own plan to look for nearby habitable planets in May.
但是，即使面对这么多未知和可能性，中国于今年五月宣布了自己的寻找邻近可移居星球计划。
The project, called “Closeby Habitable Exoplanet Survey”, or CHES, if carried out, will be the first space mission specifically designed to hunt for habitable Earth-like planets around nearby Sun-like stars via a space telescope.
这项“近邻宜居行星巡天计划”，也叫CHES，在开展之后，将会是第一个通过空间望远镜专门为在类日恒星附近寻找可移居类地星球设计的太空计划。
So, how is CHES better for exoplanet discovery?
那么CHES对于系外行星的发现有什么优势呢？
Well, to observe a planet is fairly easy.
观测行星其实很简单。
Scientists identify planets on a daily basis using a combination of the transit method, the radial-velocity method, direct Imaging or gravitational microlensing.
科学家们几乎每天都在发现它们。主要是通过几种不同的观测方法，包括凌星法、视向速度法、直接观测法或微引力透镜法。
Now I know that's a lot of terms that I will not expand in this episode, but you can Google them if you like!
这些术语听起来可能太晦涩了，我暂且不在这里展开赘述，但如果你感兴趣的话可以自己搜搜！
To determine if a planet is habitable, meaning “suitable for life to evolve,” there are a few vital things that scientists are looking for.
为了确定一个行星是否宜居，或者是是否“适宜万物生长”，科学家会关注这个行星上的几个关键要素。
Firstly, if it orbits in a habitable zone of its host star, or what the scientists call, the “Goldilocks zone”.
首先是行星的运行轨道与其母星的距离是否合适，即是否处在科学家所说的“宜居带”中。
A distance that's not too close or too far to have liquid water.
它指的是一个能让行星上存在液态水的适宜距离。
Water is always important, right?
水是生命之源嘛。
And then, of course, you want to know the size of the planet.
其次，行星的大小也同样值得关注。
Scientists always wanted to be a lot larger than our planet Earth, because they believe that the larger the planet is, the higher chance of it to have a gravity that can hold on for atmosphere.
科学家们倾向于寻找一个比地球大得多的行星，因为他们相信这个星球越大，其产生的重力更有可能留住大气层。
And then, the star must be a certain type, preferably a red or yellow dwarf star, just like our sun, that has had a stable existence for over 4.5 billion years.
最后，对于行星的母星也有特殊要求，最好是红矮星或黄矮星，就像我们的太阳一样，它已经稳定存在了超过45亿年。
And all of that cannot be done by just looking at it from Earth, right?
要知道这些信息，光靠在地球上进行观测是远远不够的。
So, CHES will observe around 100 sun-like stars that are specifically 32 light-years away and will hopefully discover roughly 50 Earth-like planets, or they should be called “super-Earth planets” that are up to 10 times the mass of Earth in habitable zones.
那么“近邻宜居行星巡天计划”将扫描约100个32光年以外的类太阳恒星，理想状态下将探测出约50个宜居带类地行星，或者也可以叫它们“超级地球”，它们的质量可能有10个地球那么重，且都在宜居带内。
The project will feature a 1.2-meter aperture optical telescope that's able to take high-quality images.
CHES计划有效载荷为一台口径1.2米，能够拍摄高质量图像的光学望远镜。
And it'll be placed into a halo orbit at the second Lagrange Point of the Earth-Sun system and maintain a stable operation for a period of at least five years.
CHES空间望远镜将被送入日地系统第二拉格朗日点的Halo轨道，并在该轨道维持至少5年的稳定运行。
And CHES will conduct extensive survey on the number, true planetary masses and three-dimensional orbits of those habitable planets.
CHES计划将详细普查宜居行星的数目、真实质量和三维轨道等信息。
Now, that's a lot richer than those predecessor telescopes provided.
这些数据将极大丰富那些“先驱者”望远镜所带回的成果。
But maybe, with all these powerful telescopes, whether for the one from China's CHES mission or Webb or Gaia, we’ll soon find out a Tatooine lying somewhere in the universe.
但或许，在这一系列强大的望远镜的加持下，无论是韦伯、盖亚，还是中国的CHES计划，相信我们终将在宇宙的某个角落发现另一片世外桃源。
As for the question of how to get to an exoplanet, it’s for another episode of Tech Please!
至于如何抵达系外星球的问题，我们将在另一期的《科技脱口秀》中进行求索。
This is Chenchen, till next time!
我是晨辰，我们下次再见！
