5.Kepler-186f
5.开普勒-186f

Kepler-186f is an exoplanet orbiting the star Kepler-186 about 500 light-years from Earth. Discovered in 2014, it is the first Earth-size exoplanet found to be orbiting in its star's habitable zone.
开普勒-186f距离地球约500光年，是一颗围绕开普勒-186运行的太阳系外行星。开普勒-186f于2014年被发现，是首颗在恒星的宜居带内被发现的类地系外行星。
Less than 10 percent greater than Earth's size, it is the closest "match" to our home planet. Any other similarities, like density, are unknown. But the presumably rocky composition can be hypothesized simply based on the exoplanet's size.
它的体积比地球大10%不到，是和地球最“接近”的行星。而对于该行星的其他相似之处，如密度等，我们均一无所知。但我们可以根据它的大小判断出这很有可能是一颗岩石行星。
Both its Earthlike size and its location in the habitable zone are what make Kepler-186f a more likely candidate to accommodate life. However, the presence of water has not been confirmed because of a lack of proper information, such as temperature.
体积与地球相差无几、同样位于宜居带，这两个条件使开普勒-186f成为候选的宜居星球。然而，由于温度等相关信息的缺乏，该星球上是否存在液态水尚未得到确认。
As Earth is our only known host of life, the theory is that a place like Earth in other ways might also be home to some form of life as we know it.
地球是我们已知的唯一存在生命的星球，已知理论表明，与地球类似的行星可能存在某种生命。

4.Kepler-452b
4.开普勒-452b

According to NASA, Kepler-452b could be "one of the best (places) to find extraterrestrial life." This exoplanet, however, may prove to be difficult to explore. It's over 1,000 light-years away. Even so, scientists have confirmed that Kepler-452b is located in its star's habitable zone, along with several companion exoplanets.
据美国宇航局资料显示，开普勒-452b可能是“最有机会找到外星生命的地方之一”。然而，这颗星球距地球超过1000光年，因此对这颗系外行星进行探索可能十分困难。即便如此，科学家也证实了开普勒-452b和几颗系外伴星均位于其恒星的宜居带。
For a while, Kepler-452b was known for being the closest to Earth's size. That honor now goes to Kepler-186f. Still, Kepler-452b's star is much more Sunlike, which is certainly interesting. Furthermore, this exoplanet is one of science's most notable subjects, particularly in the eyes of the SETI (Search for Extraterrestrial Intelligence) Institute, a leader in the exploration for extraterrestrial life.
有段时间，开普勒-452b以体积最接近地球而闻名，而现在，开普勒-186f获此殊荣。而同样有趣的是，开普勒-452b所环绕的恒星和太阳类似。此外，这颗系外行星是目前科学研究的热点，在地外生命探索领域的领导者SETI（地外文明探索）机构看来尤其如此。

3.LHS 1140b
3.LHS 1140b

This "super-Earth" is a recently discovered exoplanet that is in its star's habitable zone. LHS 1140b is considered by some scientists to be one of our best opportunities to find other life-forms.
这颗“超级地球”是最近发现的太阳系外行星，它位于其恒星的宜居带内。有的科学家认为LHS 1140b是最有可能找到其他生命形式的星球之一。
A super-Earth is an exoplanet that is up to 10 times more massive than our Earth. It is often presumed that a super-Earth is rocky, although we can't be sure without other observations. LHS 1140b, the mother of all super-Earths, is also believed to be rocky with an iron core... and to possibly have aliens.
超级地球是指体积比地球大十倍的太阳系外行星。尽管我们无法通过其他观察进行确认，但我们认为这些超级地球主要由岩石构成。作为所有超级地球之母，LHS 1140b也被认为是一颗内核为金属的岩石行星，还有可能存在外星人。
At only 40 light-years away, this exoplanet is in a good position for us to send a signal to intelligent life there, should it exist. In addition to LHS 1140b's proximity to Earth, the exoplanet's slower rotation speed makes LHS 1140b easier to observe.
如果有智慧生命存在，那么距离地球仅仅40光年的LHS 1140b很适合我们向其发射交流信号。LHS 1140b除了位置靠近地球，它的自转也较慢，我们对其进行观察会更容易些。

2.Tabby's Star
2.虎斑星

Tabby's Star, or KIC 8462852, has received a lot of buzz for being the host of an "alien megastructure." Well, maybe.
虎斑星又名KIC 8462852，因该星球上可能存在“外星巨型建筑”，很多人对它议论纷纷。
At 1,500 light-years away from Earth, this star was discovered by Yale astronomer Tabetha Boyajian and noted for its peculiar behavior. Tabby's Star dims at such extreme rates over time that the dimming cannot be attributed to an eclipsing planet. Other explanations include an unidentified space object or the more fun explanation, aliens.
耶鲁大学天文学家塔贝莎·博雅健发现了这颗距离地球1500光年的恒星，它以奇特而著称。随着时间的推移，虎斑星会突然变暗，这样的亮度骤降不能归结为凌日现象造成。有解释成是不明宇宙物体造成的，更有趣的说是由外星人造成的。
An alien megastructure is basically a giant device that captures energy from a star and converts it into something more useful. When a star loses energy, it dims. So the idea of an alien megastructure makes sense, at least a little bit.
有一种假说认为，这种外星建筑其实是一台巨型装置，能捕捉恒星能量并能将其转化为更有用东西。当能量被装置吸收时，恒星会变暗。所以外星巨型建筑的假想是有一点道理的。
However, the most recent and most likely theory about Tabby's Star is that it ate its own planet, which is certainly fascinating in its own right. Still, aliens have not been completely ruled out.
然而，最近提出的最可靠的理论是虎斑星吞噬了自己的行星，这个理论本身就是很吸引人的。不过也没有完全排除外星人假想。

1.Ganymede
1.木卫三

Another one of Jupiter's moons might contain life. Like the other moons, Ganymede is thought to have an ocean beneath its crust. Surprisingly, this ocean could contain more water than Earth itself. In fact, investigation into Ganymede's surface shows that there may have been a flood once when liquid water escaped from beneath the surface through cracks or other openings.
木星的另一颗卫星也可能存在生命。和其他卫星一样，木卫三被认为在其地壳下存在海洋。令人惊讶的是，这片海洋的液态水含量超过地球。事实上，对木卫三地表的调查显示，当液态水从地表下通过裂缝或其他出口喷出时，可能会形成洪水。
The exploration of this moon even brought about new research methods. For example, by analyzing magnetic fields, scientists found that they can possibly deduce information about the interior of the object, including whether liquid water is present.
对这颗卫星的探索还带来了新的研究方法。例如，通过分析磁场，科学家发现他们可以推断出物体内部的信息，包括是否存在液态水。
As of early 2017, there is no mission exploring Ganymede. But a probe called JUICE (JUpiter ICy moons Explorer) is set to explore Jupiter's moons further in the next several years.
截止2017年初，还没有探索木卫三的任务。但是，一个名称为JUICE（木星冰月探测器）的探测器将在未来几年内进一步探索木星的卫星。