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In 2015, New Horizons made its famous Pluto flyby, but once it left Pluto, its mission wasn't over.
2015年，新视野号进行了众所周知的冥王星飞近探测，但离开冥王星并不意味着任务的结束。
For the last few years, the spacecraft has been traveling toward an even more distant object that's been frozen in time for billions of years.
过去几年来，新视野号一直在朝着一个更远的物体飞行。这个物体数十亿年来一直处于冰冻的状态。
It's an icy world called 2014 MU69.
这里是冰封的世界，名作2014 MU69。
The team has nicknamed it Ultima Thule, and while you're ringing in the New Year on January 1st, New Horizons will finally fly by it.
科学团队给它起了一个绰号——天涯海角。当1月1日大家正在迎接新年到来的时候，新视野号就会在跋涉千山万水后飞过这里了。
Ultima Thule is a rock about the size of a city and is 6.6 billion kilometers away.
天涯海角是一块石头，其大小跟一座城市差不多，距离我们有66亿公里远。
It's located in the Kuiper belt, way out past the orbit of Pluto.
这里位于凯伯带，与冥王星的轨道有重合。
And that makes it the most distant object a spacecraft has ever visited.
这就使它成为航天器去过的最远的地方。
But you classical lit scholars out there already knew that because Ultima Thule means it's beyond the known world.
但学者们早就知道这一点了，因为“天涯海角”这个名字就已经表明它在已知世界之外了。
Way to be interdisciplinary, NASA!
这就是美国宇航局的跨学科之路呀！
Back in August, New Horizons sent NASA a grainy postcard with its first picture of Ultima Thule, and since then, the probe has been hurtling toward its target at about 14 kilometers per second.
回顾8月的时候，新视野号发送给美国宇航局一张明信片，附着人类给天涯海角拍下的第一张照片。从那时起，新视野号就开始朝着目标以14km/s的速度行进。
That's more than 50,000 kilometers per hour!
也就是5万多km/h！
New Horizons is going so fast that it won't be able to slow down enough to orbit the object.
新视野号的速度极快，所以就算再减速也不足以使速度达到可以环绕冥王星的程度。
Instead, it will just make a flyby, like it did with Pluto.
相反，新视野号只会做飞近探测，就像当初飞近探测冥王星那样。
But that doesn't mean it will be easy.
但这不意味着飞近探测难度就很低。
We don't understand Ultima Thule's orbit very well, so it's been hard to aim for, and astronomers have had to track it constantly.
我们不是很了解天涯海角的轨道，所以很难定一个具体的目标，天文学家
But since it's just a dim little speck in a sky full of stars, it's not easy to track, either.
但鉴于天涯海角在满是繁星的天空里只是亮度不大的小点儿，所以也很难追踪。
We don't even know if it's a single object or two giant rocks orbiting really close together.
我们甚至不知道天涯海角是一个单个的物体，还是2个巨大的岩石彼此紧密环行。
To make things more complicated, New Horizons is also trying to get even closer to Ultima Thule than it did to Pluto.
让情况更为复杂的是：新视野号还在努力靠近天涯海角，就像曾经靠近冥王星那样。
If all goes well, it's planning to skim just 3,500 kilometers above the surface.
如果一切进展顺利，新视野号将会在天涯海角地表上空飞行3500公里。
Which, at 14 kilometers per second, means there's virtually no room for error.
也就是14km/s的速度，这就意味着容错率几乎为0。
But it'll to be worth it.
但这一切还是值得的。
Visiting Ultima Thule is like exploring an amazingly well preserved, 4-billion-year-old fossil.
去往天涯海角就像探索一颗40亿年间依然保存完好的化石。
It's an ancient rock that formed at the same time as our solar system.
这是一颗跟我们太阳系同时形成的古代岩石。
And ever since then, it's been frozen solid at only a few dozen degrees Celsius above absolute zero.
从那以后，它就一直保持着冰冻的状态，温度只比绝对零度高几摄氏度。
So, in a way, visiting Ultima Thule is like going back in time.
所以，从某种程度来说，天涯海角就像在经历时光倒流。
We'll get to explore a snapshot taken of our neighborhood as it was being born.
我们需要找到我们临近地区刚诞生时候的照片。
Scientists are planning to look at the shape and surface features of Ultima Thule, see whether or not it has rings, and search for clues about how it formed.
科学家计划观测天涯海角的形态和地表特征，看看它是否有光环，并寻找它形成的线索。
They're even going to look for an atmosphere, though they don't expect to find one.
他们甚至要寻找一个大气层，虽然他们也没抱希望能找到。
Aside from Pluto, this is the first close-up look we'll get at an object in the Kuiper Belt, which we didn't even know existed until 1992.
除了冥王星之外，这是我们首次近距离观测凯伯带里的物体。而这个物体是我们1992年才知道其存在的。
But now we understand it's like a vault full of secrets that can tell us about the origin of the solar system.
但现在，我们对它的理解是：它是一个拱形结构，里面有很多秘密。如果能了解这些秘密，我们就能知道太阳系的起源。
Primitive space rocks may be even more important to us than we realized, too.
原始太空里的石头对我们的重要性可能比我们意识到的还要大。
Earlier this week, a team of researchers announced in Nature Communications that, in a lab, they had made the sugar component of DNA under extraterrestrial conditions.
本周初，一组研究人员在《自然通讯》上宣布，他们在实验室里，在地球外的环境中研制出了脱氧核糖核酸（DNA）的糖分组成。
Meaning that it's possible that the building blocks of DNA might not have originated on Earth.
这意味着，DNA的组成成分有可能并不是源于地球。
Now, this idea isn't new. In the last several decades, we've found other sugars on a few different meteorites.
这个想法也不是第一次萌生。在过去的几十年间，我们在多个不同的陨石中也发现了糖分。
That's led scientists to suspect that the sugars that support life could have originally come to Earth on space rocks.
这让科学家开始怀疑：支持生命存续的糖分可能从太空里的石头来到地球的。
But we still don't understand how sugars got on meteorites in the first place.
但我们还是不知道糖分为什么会存在于陨石中。
To figure it out, researchers have been trying to create those compounds under conditions that mimic interstellar space.
为了弄清这个问题，研究人员一直在努力模仿宇宙空间的环境，并在这样的环境里试图研制出糖分的化合物。
In this paper, the team made those conditions using a process called ultraviolet irradiation.
这篇论文的研究小组是通过一个名为紫外线照射的过程来创造实验环境的。
Ironically, it's what we normally use for sterilizing things, like water.
讽刺的是：这个环境正是我们一般情况下用来消毒的方法，比如给水消毒。
We use it to get rid of living things, but these scientists used it to create organic molecules from conditions that were not biological in the first place.
我们用这个方法来杀死生物，但这组科学家用这种方法在非生物宜居的条件下培育有机分子。
They started with a mixture of frozen water and methanol at -261°C.
起初，他们在零下261℃的环境下用结冰的水和甲醇来进行培育。
Kind of like something you might find in a cloud in interstellar space.
有点像我们在宇宙空间的云团中可能找到的物质。
Then, they shined ultraviolet light on it, like our Sun did to rocks billions of years ago.
随后，他们用紫外线照射实验的物质，就像几十亿年前太阳照射岩石一样。
When the light interacted with the ice, it produced a chemical reaction.
每当光线与冰接触，就会发生化学反应。
And the residue it created contained a bunch of different sugars and other compounds.
而化学反应产生的残余物包含很多不同类型的糖分和其他化合物。
Many of them had been seen before in similar experiments.
很多残余物是我们在类似实验中看到过的。
But this time, scientists also detected a compound called 2-deoxyribose.
但这一次，科学家还探测到了一种名为脱氧核糖的化合物。
This is a type of sugar called a deoxy sugar, which makes up DNA.
脱氧核糖也是脱氧糖的一种，是DNA的组成成分。
Along with it, they found compounds that can be derived from deoxy sugars and that we've also found on actual meteorites.
除此之外，研究人员还发现了可以从脱氧糖中提取出的化合物，这也是我们在陨石中发现的成分。
That doesn't mean those rocks used to contain deoxy sugars, we don't have evidence for that.
这并不意味着这些岩石以前就还有脱氧糖，我们可没找到这方面的证据。
But it's not impossible. Either way, this study adds to a list of sugars and other organic compounds that can be created, and have been created, in conditions a lot like the sterile environment of space.
但这也不是不可能的。无论如何，该研究添加了可以产生并已经产生的糖类和其他化合物。而产生的环境跟宇宙空间里的无菌环境极为相似。
It's the most convincing evidence yet that the sugars that gave rise to life on Earth could have been created in totally uninhabitable worlds.
这个证据极有说服力，可以证明糖分支持了地球上的生命，而这些糖分可能是在完全不宜居的宇宙空间中产生的。
Places like comets, asteroids, and clumps of space dust, places we don't associate with life at all.
彗星、小行星、宇宙尘埃都是我们认为完全与生命无关的存在。
It also hints at how humans came to be.
该证据也暗示了人类可能的形成过程，
It suggests that, as violent as it sounds, all the meteorites that bombarded the early Earth could have helped life emerge.
还表明所有曾经在地球初期撞击过地球的陨石可能也曾助力实现生命的形成，虽然撞击的过程听起来很暴力。
One thing we really need, though, is direct evidence.
我们切实需要的是直接证据。
So next, scientists will be looking for these deoxy sugars on meteorites themselves.
所以接下来，科学家将会在陨石中寻找脱氧糖的存在。
And this study gives them a good reason to keep looking.
该研究让他们有了继续观测研究的充分理由。
Thanks for watching this episode of SciShow Space News!
感谢收看本期的《太空科学秀》！
This will actually be our last regular news episode for 2018, but don't worry:
本期是我们2018年的最后一期，不过不要担心：
We have a few special things planned, and we'll be back in January.
有一些特殊的节目主题，我们已经在筹备中了，敬请期待一月份吧。
If you don't want to miss anything, you can go to youtube.com/scishowspace and subscribe.
如果大家不想错过任何一期节目，可以订阅youtube.com/scishowspace。
