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After more than 25 years of studying exoplanets, and centuries of looking around our own neighborhood, scientists have a pretty good idea of how solar systems are supposed to work.
在研究了25年的系外行星以及研究太阳系数个世纪之后科学家对太阳系的运作方式有了较为充分的了解。
Generally, you start with a big cloud of gas, which collapses to form a disk.
一开始，要有一大团气体云，气体云崩塌之后会形成一个圆盘。
Then, over time, you get a bunch of planets and asteroids and debris.
然后，随着时间的流逝，会出现行星、小行星和一些碎片。
This idea has been backed up by thousands of observations and countless models, but sometimes, scientists still find solar systems that throw them for a loop.
这个想法经过了上千次观察和无数个模型的证实，但有时候，科学家还是会发现太阳系让人意想不到的地方。
From gigantic planets too close to their stars, to those in unfathomably wide orbits, the discovery of seemingly impossible solar systems has puzzled astronomers.
太阳系里既有离所环绕恒星距离很近的行星，也有宽的异常的轨道，这些现象似乎不可能出现在太阳系里，但却出现了，这让天文学家百思不得其解。
According to their well-tested ideas, these systems shouldn't exist at all. But they do.
根据科学家多次证实的想法，这些系统本不应该存在，但却真实地存在着。
So, in no particular order, here are three of them, and what they mean for science.
下面介绍其中3个系统以及它们在科学史上的意义，排名不分先后。
First, there's the star HR8799, which you can add to our ongoing list of hard-to-remember names.
首先是恒星HR8799，可以把它放入难记的名单里。
It's 129 light-years from Earth, and it's orbited by four gas giants.
该恒星距离地球有129光年的距离，有4个气体巨星环绕它运行。
The latest planet was announced in 2010, and it's around 7 times the mass of Jupiter, orbiting 14.5 astronomical units, or AU, from its star.
最后一颗恒星是在2010年公之于众的，其质量是木星的近7倍，距离其所环绕恒信更有14.5个气体巨星天文单位（AU）。
In other words, it orbits about fourteen and a half times farther from its star than the Earth does the Sun.
换言之，它与所环绕恒星之间的距离是日地距离的近14.5倍。
That's roughly equivalent to halfway between the orbits of Saturn and Uranus, but for such a big planet, that's considered relatively close.
这近乎是土星和天王星之间轨道的一半，但对于如此庞大的行星来说，这个距离已经相当近了。
By itself, this isn't all that unusual. But the story is made more complicated because the other three planets around this star orbit much farther away.
就它自己而言，这一切都挺正常的。不过，它的情况变得更为复杂是因为该恒星附近的另外3颗行星的环绕距离却更远。
And that makes the system as a whole pretty tricky to explain.
这就让这个系统成了让人不解的存在。
Right now, gas giants are thought to form in one of two ways. One is accretion.
目前，一般认为，气体巨星可以由2种方式形成。一种是吸积盘的方式。
In this method, particles of dust clump together to make a solid core, whose gravity attracts a thick atmosphere over millions of years.
以这种方式形成的时候，灰尘粒子会聚积在一起形成一个固态内核，其引力可以吸引厚重的大气层长达数百年的时间。
The other is by fragmentation, where small patches of gas form planets directly over just 10,000 years.
另一种方式是碎片化方式，即一些小的气团用仅1万年的时间直接形成行星。
But neither of these models can explain the formation of all four siblings in this solar system.
但这2种模型都无法解释太阳系里所有由4个星体组成的系统。
Accretion can explain the inner planet, but not the outer three.
吸积盘的方式可以解释里面的那颗行星，但无法解释外面的3个。
Since that trio is so far from the star, the gas to make their atmospheres would have dissipated in the time it took a rocky core to form.
由于外面的3颗行星离恒星太过遥远，所以这些气体在形成大气层之前就会形成岩石内核的时候消散。
On the flip side, fragmentation can explain the outer three planets, but not the inner one.
而碎片化的方式可以解释外面的3颗行星，却无法解释里面的那一颗。
At 14.5 AU, it's thought that the gaseous disk around the young star would have been too hot and fast-moving to form a planet.
在14.5AU的距离上，这颗刚形成没多久的恒星附近虽然有气体圆盘，但由于温度过高以及移速过快，所以无法形成行星。
And while it's possible that both fragmentation and accretion would have made this system, scientists think it's unlikely, since among other things, the planets are all a similar size.
虽然这两种方式都有可能形成了这个系统，但科学家认为这是不太可能的，因为这些行星个头很小。
Until we get a better look, we won't know for sure what happened.
在能进行更为精密的观测之前，我们也无法确定事情的原委。
But based on a study published in 2013, we at least have a hypothesis.
不过，根据2013年发布的一项研究，我们至少有一个假说。
That year, research into the atmosphere of the outermost planet revealed that it had a comparatively oxygen-poor composition.
2013年，对最外面那颗行星大气层的研究表明这颗行星的组成结构中，氧的含量很少。
And that actually lent support to the accretion theory, at least, a modified version of it.
这一观测为吸积盘方式提供了支持，至少它与吸积盘方式差距不大。
Instead of a slow-forming rocky core, scientists think a core made of water ice could have formed, depleting the disk of oxygen.
科学家认为，内核并非是慢速形成的岩石内核，而是由冰形成的内核，这样就可以耗尽圆盘中的氧气了。
This core could take shape relatively quickly, attracting an atmosphere before the gas dissipated.
该内核成型的速度相对较快，可以在气体消散之前就吸聚形成大气层。
So we probably don't need to throw out our models just yet.
所以，我们的模型还是有用的。
Now, sometimes, there are even bigger planetary puzzles we need to solve, like in the case of this planet.
现在，有时候会遇到一些更大的行星难题，比如下面这颗行星。
I'm just gonna call it 2MASS for short, because let's be honest:
我就姑且简称它为2MASS，因为实话说：
It's 100 light-years away, so you probably won't need to say its full name all that much.
它距离我们有100光年的距离，所以也不必拘泥于是否说全名字了。
This object was discovered in 2009, but at the time, scientists thought it was a rogue planet wandering around without a parent star, which happens sometimes.
该行星是2009年发现的，那时候，科学家以为它是一颗流浪的行星，四处游荡只因没有母星，这种情况是偶有发生的。
Then, in 2016, new analyses revealed that 2MASS wasn't rogue after all.
后来，2016年的时候，新分析表明，这颗行星根本不是流浪行星。
Its motion was actually linked to a tiny red dwarf star.
其运动情况实际上是跟一颗小型红矮星相关联的。
But its orbit was unlike anything we've seen elsewhere.
但其轨道却和我们之前在其他地方看到的不一样。
2MASS is separated from its star by roughly 1 trillion kilometers, nearly 7,000 times the distance between Earth and the Sun.
这颗行星距离其恒星大概有1万亿公里的距离，是日地距离的近7000倍。
Scientists think there's no way this system could have formed from a disk of gas and dust, because the two pieces are just too far apart.
科学家认为，该系统是不可能形成气体和灰尘组成的圆盘的，因为恒星和行星距离太远了。
And they still don't know for sure how these objects maintain their unbelievably long-distance relationship, or how they got together in the first place.
而且他们还不确定这些物体是如何保持这种距离如此远的关系的，也不知道他们起初是如何形成这种关系的。
However, one of the researchers who discovered the system suggested that a random filament of gas could have pushed the once-rogue planet and the star together in the same direction.
不过，一位发现该系统的研究人员认为，一股随意出现的气体流可能推动这两颗曾经流浪的星体朝同一方向运动。
So again, it looks like the models can stay. Finally, TRAPPIST-1.
所以，我们再一次发现模型还是有用的。下面介绍最后一颗，也就是TRAPPIST-1。
It's probably one of the most famous discoveries of the last few years, and we've talked about it more than once on SciShow Space.
这很有可能是过去几年里最出名的发现之一了，我们在节目中多次提过它。
This system is about 40 light-years away, and it contains seven small, rocky planets orbiting their star, a cool red dwarf, incredibly closely.
该系统距离我们近40光年，里面有7颗由岩石组成的小型行星，环绕着一颗红矮星恒星，距离十分近。
In fact, all seven are closer than Mercury is to our Sun.
实际上，这7颗行星距离恒星的距离比水星与太阳之间的距离还要短。
But how all the planets got so buddy-buddy is a bit of a mystery.
但这些行星与恒星之间为何如此亲密却是个谜。
For the planets to accrete that close in, you'd need a very dense disk of gas.
行星要通过吸积盘的方式离得如此近，就需要一个密度很大的气体盘。
But if it was dense, you'd expect the planets that grew from it to be much bigger than they are.
但如果密度很大，这些从其中形成的行星就会比现在要大得多。
There's always the possibility that the planets formed farther out, in a more empty region, and migrated inward, but that doesn't explain their regular small size, either.
虽然行星确实有可能在更远的地方形成，比如在空旷的地方，并向里迁移，但这并不能解释它们大小不规则的情况。
So, in 2017, a third explanation was proposed.
于是，2017年的时候，又诞生了第三种说法。
Scientists from the University of Amsterdam suggested that pebble-sized debris first migrated inward to form small planets.
达姆斯特丹大学的一些科学家认为，卵石大小的碎片先是向内迁移，形成了小行星。
Those small planets disturbed the disk of debris around them, and that disturbance caused them to move into their current positions before they got too big.
这些小行星的出现扰乱了它们周围由碎片组成的圆盘，这种扰乱行为导致它们向内迁移到现在的位置，还没来得及变得太大。
Like with the other mysteries, we'll need more observations to be sure.
不过，就像其他未知之谜一样，我们还需要更多的观测才能确实是否如此。
But since everyone is interested in TRAPPIST-1 because of its potential habitability, there's likely more data to come.
不过，由于大家对可能宜居的TRAPPIST-1都感兴趣，所以很有可能还会有更多的信息出现。
These three solar systems, and other neighborhoods like them, have forced scientists to rethink their models of planetary formation, but not in a way that completely breaks astronomy.
这3个太阳系里的系统以及与它们相似的一些邻居迫使科学家重新思考行星形成的诸多模型，但思考的方式要符合天文学规律。
Because that's the thing about research: Every new finding that contradicts your theories isn't Earth-shattering, or solar system-shattering, in this case.
因为研究的第一原则是：与理论相冲突的新发现不能破坏地球和太阳系本身的规律。
Sometimes, it just means you're missing a piece of the puzzle, and it's up to clever and thoughtful research to figure it out.
有时候，这只是意味着我们错过解开某个谜题的机会了，但总有方式精巧、深思熟虑的研究能解开谜题。
Of course, finding that missing piece isn't always easy when your puzzle is hundreds of light-years away.
当然，解开数百光年以外的谜题并非易事。
But maybe that's what makes it fun. Thanks for watching this episode of SciShow Space!
但过程足够有乐趣。感谢收看本期的《太空科学秀》！
Scientists find seemingly impossible things out there all the time, but some mysteries are larger than others.
科学家一直在不断地发现看似不可能发生的现象，但一些谜题要比另一些还要难解。
If you want to learn about three planets that just straight-up shouldn't exist, you can watch our episode about them.
如果大家想了解这3颗本不应该存在的行星的话，可以观看我们专门的视频集锦。
