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After years of searching, there's one place in the solar system where we've managed to find life. Okay, so I'm talking about Earth.
搜寻了很多年之后，我们终于得以在太阳系里的一个地方发现生命，想必大家也猜到了，就是地球没错。
But there are other bodies that astronomers suspect could be habitable, at least for special types of single-celled life forms.
但天文学家认为，还有其他一些星体是适宜人类居住的，至少适宜一些特殊种类的单细胞生物。
Probably not, like, space hippos or anything.Although that would be awesome.
不过，空间河马这种还是算了吧。虽然还挺酷的。
One of those bodies is Saturn's moon Enceladus, which almost definitely has an ocean's worth of liquid water underneath its icy surface.
其中一个就是土卫二了，其表面虽然覆盖着冰层，但冰层下面却是一片汪洋。
Based on what we know about life, we've thought this environment could be habitable, but we haven't known that for sure.
根据我们目前对生命的了解情况，我们认为土卫二环境宜居，但对于这一点，我们也不是100%确定。
But now, we do. According to research published on Tuesday in Nature Communications,
不过如今，我们有确凿的证据了，根据周二《自然通讯》上发布的一项研究成果，
Enceladus' environment could totally be habitable for at least one real-world microbe.
至少有一种现实世界的微生物是可以在土卫二的环境里存活下来的。
We don't know the exact conditions in Enceladus' oceans, but astronomers do have some educated guesses.
虽然我们不了解土卫二上海洋的具体情况，但天文学家根据职业经验还是做了一些猜测。
Plumes of water actually shoot into space through cracks at the moon's southern pole,
水是从土卫二南极的裂缝里涌出的，
and we've driven the Cassini spacecraft through some of them to figure out what compounds were inside.
我们已经派卡西尼号太空船探测了这些裂缝，想看看土卫二内部有什么化合物。
Besides regular old H2O, there were molecules like carbon dioxide, hydrogen, ammonia, and methane.
除了屡见不鲜的纯净水之外，还有二氧化碳、氢、氨、甲烷。
That last one's especially important, because methane is produced by all kinds of organisms on Earth, including single-celled archaea.
甲烷尤为重要，因为地球上任何种类的生物都能产生甲烷，单细胞生物也不例外。
So this could be an indicator that there's life on Enceladus, too.
所以，甲烷的存在也可以作为土卫二上存在生命的例证。
But before scientists got ahead of themselves, they had to see if methane-producing organisms could even survive there.
不过，科学家在欣喜若狂之前，要先确认可以产生甲烷的生物是否能在土卫二上存活。
That's where this new paper came in. In this study, a team of researchers got together three different, methane-producing species of archaea.
这一点也是这篇论文的切入点，在该研究中，一组研究人员找来了三种可以产生甲烷的古生菌，它们的种类各自不同。
Then they cultivated them in an environment we think is similar to Enceladus' southern ocean.
然后，研究人员将这些古生菌放在与土卫二南部海洋相似的环境中进行培养。
Specifically, they looked at the composition of gases, the pressure, and the pH.
研究人员尤其关注了气体、压强、PH值的情况。
Some of the gases on Enceladus like ammonia, actually prevent certain species of archaea from growing.
其实，土卫二上有些气体比如氨，会抑制某些古生菌的生长。
So they wanted to see if any of these three could not just survive, but thrive. And one did.
所以，研究人员想看看这三种古生菌中的哪种不仅可以存活下来，还可以大量繁殖。而确有一种古生菌做到了。
It's a little microbe known as Methanothermococcus okinawensis, which is a mouthful.
这种古生菌体型非常之小，学名为冲绳甲烷球菌。
It came from a hydrothermal vent field almost a thousand meters below sea level in the East China Sea.
这种古生菌来自中国东海的深海热液喷口处，大概在海平面1000米以下。
Of course, just because one species could thrive in the lab doesn't mean there are definitely microbes swimming on another world.
当然了，仅凭一种生物能在实验室里存活的例子是无法证明另外一个世界里也一定有微生物存活的。
The researchers caution that methane can also be created through chemical reactions that don't require living organisms.
对此，研究人员也警示称，甲烷是可以通过非生物之间的化学反应产生的。
And even if there is life making methane on Enceladus, geologic processes are definitely responsible for at least some of it, too.
而且，即便土卫二上存在能产生甲烷的生物，地质进程也一定产生了作用。
Still, the fact that we've found one species that could theoretically live there suggests there could also be others.
不过，理论上来讲，我们能在土卫二上发现一种生物这件事可以表明或许有其他生物的存在。
And that strengthens astrobiologists' hope for finding life beyond the rock we call home.
而这也加大了天体生物学家在地球之外发现其他生命的希望。
Meanwhile, on pretty much the other side of the observable universe, a star went supernova.
这个话题先说到这儿。另一边呢，在我们能观测到的宇宙的另一端，有一颗恒星消亡变为超新星了。
Well, it actually went supernova about 10 and a half billion years ago.
不过，其实这颗恒星是在150亿年前演变为超新星的。
But since light can only travel so fast, we had to wait a while to see it. The good news is, it was totally worth the wait.
不过由于光速是恒定的，所以我们要等一阵儿才能看到它了，但好消息是：等待是值得的，
Thanks to a study published last month in The Astrophysical Journal, we've confirmed this supernova is officially the oldest one ever detected.
因为根据《天文物理期刊》上个月发表的一则研究，我们已经确认：这颗超新星就是官方探测到过的年代最为久远的超新星了。
The cosmic explosion -- memorably dubbed DES16C2nm, was first captured in 2016 by the Dark Energy Survey.
这颗名为DES16C2nm的超新星最初是在2016年的暗能量调查(DES)里发现的。
The DES is an international collaboration trying to pin down the science behind dark energy.
暗能量调查是一项国际通力的调查项目，该项目力图找到暗能量背后的科学规律。
That's the mysterious phenomenon astronomers believe could be causing the universe's expansion to accelerate.
很多天文学家认为，暗能量是一种神秘的现象，也正是这种科学现象加速了宇宙的膨胀。
To investigate it, the survey is mapping 300 million galaxies, all billions of light-years away.
为了调查暗能量的科学规律，该研究以3亿个星系为观察目标。这3亿个星系距离地球都有几十亿光年的距离。
It isn't specifically looking for supernovas, but when you study that many galaxies, you're bound to find one or two.
研究人员并没有专门要找什么超新星，不过要观测这么多的星系，是免不了要找那么一两颗超新星的。
This one just turned out to be a special bonus and not only because of its age.
过程中碰巧走运找到了这颗超新星，但可喜可贺之处并非只在于其年代之久远。
DES16C2nm actually belongs to the rarest class of supernova, known as superluminous supernovas.
实际上，DES16C2nm这颗超新星属于最为罕见的超新星类别，也就是超级新星。
And as the name implies, they're really bright, about 100 times brighter than your typical supernova, and even brighter than some galaxies!
超级新星，顾名思义非常的明亮，其亮度是一般超新星亮度的大概100倍，甚至比有些星系还要亮。
They were discovered about a decade ago, and since then, we've only managed to identify a handful of them.
超级新星最早大概是10年前发现的，从那之后就没再发现过几颗超级新星。
We're still trying to pin down exactly how they work, but some scientists think they're caused by matter falling onto a newly-formed magnetar.
我们依然在探索超级新星的具体运行方式。不过，有些科学家认为，超级新星之所以形成是因为有物质掉落在了某颗新形成的磁星上。
Magnetars are the rapidly spinning, super dense cores of massive stars that went supernova,
磁星转速极快。磁星是由大质量恒星密度极大的内核演变为超新星后得来的，
and they have a magnetic field 100 trillion times stronger than Earth's. And that makes them emit a lot of energy.
而且磁星的磁场强度是地球的100万亿倍，所以，磁星会释放巨大的能量。
As that energy interacts with matter falling onto the magnetar, it makes the supernova extra bright.
这股能量与掉落在这颗磁星上的物质进行反应，这就使得这颗超新星亮度极大。
Now that they've spotted one superluminous supernova, astronomers can go back into the DES data to see if they can find more.
鉴于天文学家已经发现了一颗超级新星，他们也可以从暗能量数据中试图发现更多颗超级新星。
And future projects, like NASA's Wide-field Infrared Survey Telescope, will also be able to detect ones even more distant.
而且未来还会有一些项目，比如美国宇航局的广角红外巡天望远镜项目，也可以探测到更远的超新星。
It'll be able to find supernovas from when the universe was less than a billion years old!
该项目甚至还可以探测到宇宙初生10亿年内的超级新星！
And this is important because, the more distant superluminous supernovas we can find, the more we can understand how space evolved.
这一点很重要，因为我们能发现的超级新星越远，我们对宇宙发展历程的了解就越多。
Information on these supernovas is few and far between, but as far as we can tell,
关于超级新星，我们知之甚少。不过，就目前所知，
they seem to explode in more or less the same way, at least within a specific range of wavelengths.
他们似乎以近乎相同的方式爆炸，至少他们爆炸的波长范围是特定的。
If this is true, we could use these supernovas as distance markers to figure out how far it is to different galaxies,
如果这一点是真的，那么我们就可以将这些超级新星作为距离刻度，
and to figure out the size and even age of the universe.
从而得知它们距离不同星系的距离，以及宇宙的大小和年龄。
With more research, they could possibly help us answer some of the many questions surrounding the expansion of the universe or even dark energy itself.
通过更多的调查，它们也可能帮助我们解答与宇宙膨胀有关的许多问题，甚至是有关暗能量的问题。
Thanks for watching this episode of SciShow Space, which we couldn't make without our Patreon supporters.
感谢收看本期的《太空科学秀》，是大家的支持让我们的节目走得更远。
A year ago this coming Tuesday, we launched another project that couldn't exist without our patrons: SciShow Psych.
一年前的周一，我们还开了另一个节目，也得到了大家的热烈支持，这个节目就是：《太空心理学》。
As a thank-you to our patrons who made that channel happen, we'll be having a birthday livestream celebration for SciShow Psych on Tuesday, March 6 at 3pm ET.
是各位促成了这个节目的开办，为了感谢大家，我们将于美国东部时间3月6日的星期二在线庆祝《太空心理学》开办一周年。
Hank and Brit will be there, as well as some of the crew, and if you're a SciShow patron, we hope you can join us for this hour-long livestream too!
汉克和布雷特等工作人员也会在场，如果您喜欢太空类节目的话，希望您也可以参加我们的周年庆！
Bring your psych questions and your party hats!
欢迎在现场提问哦！让我们燥起来！
