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Before the 1990s, we had no idea how the solar system compared to the rest of the galaxy.
在20世纪90年代之前，人类不知道太阳系与其他星系的关系。
We'd never found a planet around a foreign star, so for all we knew, our solar system was special.
我们从未在系外恒星的附近发现过行星。而且，目前就我们所知，太阳系也是独一无二的。
But in 1992, radio astronomers published their discovery of the first two exoplanets, and soon after that, the floodgates opened.
但在1992年的时候，研究无线电的几位天文学家发布了他们对2颗系外行星的发现，这是首次。在那之后，新世界的大门就打开了。
In the years since, powerful telescopes have revealed more than 3500 exoplanets in the galaxy, and research now suggests that nearly every star has at least one planet.
在那之后的这些年里，功能强大的望远镜帮我们发现了太阳系外的3500多颗系外行星。如今，研究表明，几乎每颗恒星都有至少一颗行星。
So in that respect, our solar system is just another face in the crowd, but we're still kind of a weird one.
这样来看，我们的太阳系只是人群中的另一张面孔，但是我们还是很奇特。
Because out of thousands of other systems, none look quite like ours.
因为在数千个星系中，没有哪个星系与太阳系相像。
We could be special after all. The question is why.
毕竟我们还是特殊的，因为问题本身就暴露了这一点。
Scientists have had a basic understanding of how the solar system formed since at least 1755, when the philosopher Immanuel Kant proposed the nebular hypothesis.
科学家至少1755年之后就对太阳系的形成方式有了一个基本的了解，那时候，哲学家伊曼努尔康德提出了星云假说。
He leaned on the work of other scientists of his day, and hypothesized that the Sun and planets evolved out of a cloud that collapsed under its own gravity to form a disk.
他借鉴了同时期其他科学家的成果，他提出假设：太阳和其他行星都是从一团云里演变出来的。这团云在引力的作用下分崩离析，形成了圆盘。
Then, to make a 4.6-billion-year-long story short, that disk became the plane where all of the planets orbit today.
随后经历了漫长的46亿年，长话短说，这期间，这个圆盘成了一个如今所有行星都会环绕的平面。
That basic idea has stuck around so long because it's really good at broadly describing the solar system, and extrasolar systems, too.
这个基本的想法存续了很久，因为这个想法能较为全面地描述太阳系和系外星系。
It tells us why planets generally sit in the same disk and orbit in the same direction.
这个假说让我们明白了行星为什么会在同一个圆盘内朝同一个方向运行。
It also explains why we sometimes see disks around newly formed stars.
这也能解释我们为什么有时候会在刚形成的恒星附近看到圆盘。
But it doesn't explain everything. Take Mars. It's puny.
但这并不能解释所有现象。以火星为例，它很小。
It has only about one-tenth the mass of Earth, but that shouldn't be the case.
只有地球质量的大概1/10，但本不该如此。
The nebular model tells us that, back when Mars was forming, there should have been enough material in Mars's part of the disk for it to grow much larger.
星云假说认为，在火星形成期间，圆盘上火星所在的部分，其中的材料已经足够让火星变得变大了。
And most simulations suggest that it should be closer to Earth's mass.
大多数模拟测试表明，火星质量应该和地球差不多。
So something doesn't add up. And Mars isn't the only outlier.
所以一定有什么东西没加上去，火星也不是唯一一个怪异的星球。
The solar system's planets are wildly different in size, ranging from little Mercury to giant Jupiter, but exoplanets don't usually vary much in size within one system.
太阳系里行星，大小各异，从小小的水星到庞大的木星，不一而足。但在一个星系内，系外行星大小却相差不大。
Scientists sometimes describe them as peas in a pod, because their sizing and spacing are so even. So all the variation we have here is not normal.
科学家有时候将这种现象描述为一个豆荚里的豆子，因为他们的大小和间距都很平均。所以，太阳系里的这种不均衡还挺不正常的。
And not only do we have these uncommon features, but we're also missing some of the most common ones, like super-Earths.
太阳系不仅具有这些不太常见的特征，而且还缺少一些常见的特征，比如超级地球。
These are planets more massive than ours, but less massive than something like Neptune.
超级地球是质量比恒星质量大的行星，但没有海王星等星体的质量那么大。
More than half of Sun-like stars seem to have one, but there's nothing like that here.
与太阳相似的恒星中，有一半以上似乎都有一个超级地球，但太阳系里却没有。
So our solar system has left us with a lot of mysteries.
太阳系留下了很多谜题。
Fortunately, we're starting to get to the bottom of them with the help of computer simulations.
所幸，我们在计算机模拟的帮助下已经开始了解问题的根源了。
As far as we can tell, a lot of our weirdness is probably Jupiter's fault. Thanks, Jupiter!
就我们目前所知，很多奇异现象很有可能都是木星的锅。对，就是木星！
Yeah, if you thought Jupiter was a majestic, swirly wonderland, well, yes, it is. But it's also a huge troublemaker.
没错，木星是个庄严的漩涡形仙境，但它也是一个大麻烦。
Based on evidence from meteorites, scientists believe that Jupiter was born early in the formation of the solar system, and that it may have roamed around a lot before settling in where it is today.
根据从陨石获得的数据，科学家认为，木星是在太阳系形成初期诞生的。但在那之后又过了很久才有了今天的样子。
In 2011, a team of scientists proposed a hypothesis about this called the grand tack model.
2011年，一组科学家提出了一个假说，即大策略模型。
There's still some debate about it, but it's based on simulations that suggest swirling gas around our young Sun swept up Jupiter and whisked it inward.
对此有过一些讨论，但都是基于模拟结果，而模拟结果表明太阳形成初期，其附近有旋流风，将木星向里推动。
It got to around where Mars orbits today before a newborn Saturn reined it in.
木星移动到了今天火星环行的地方，然后新生的土星通过引力作用让它的移动相对固定。
While Jupiter hung out there, its gravity likely robbed a lot of the material that would have formed Mars.
木星在这附近移动时，其引力很有可能吸引了很多物质，最后这些物质形成了火星。
Eventually, when the gas cleared out from the disk, it released its hold on the two giant planets, and they were free to wander back toward the outer solar system.
最后，当气体脱离圆盘的时候，他们不再受2大行星的吸引，可以自由地在太阳系外游荡。
Some astronomers also believe that, as it and Saturn threw around the material in the disk, they interfered with other planets as well.
一些天文学家还认为，在它和土星在圆盘中吸收物质的时候，也会影响到气体行星。
Which could explain the wide range of sizes. Jupiter might even be to blame for destroying any super-Earths.
为什么能解释太阳系里大小不一的现象呢？木星可能也是破坏超级地球的罪魁祸首之一。
According to scientists building on the grand tack model, Jupiter might have thrown off the orbits of would-be super-Earths and the material that would have formed part of them.
有一些科学家以大策略模型为研究基础。这些科学家发现，木星可能破坏了超级地球赖以运行的轨道，也破坏了可能形成轨道的物质。
If that's true, it could have created debris that slowed the whole mess down and sent it spiraling into the Sun.
如果他们的想法为真，那么木星可能产生的残骸，导致残骸减速并在旋转中逐渐成为太阳的组成部分。
We'll probably never know for sure if that's what really happened, but what is pretty clear is that the planets didn't just neatly form in one place and stay there.
我们很有可能永远也无法鉴别这个说法的真伪，但现在有一点是明确的：行星不会只在一个地方形成，也不会永远留在一个地方。
For some reason, our solar system seems to have had much more drama than others.
由于某种原因，我们的太阳系是比其他星系戏更多。
But wait, there's more. If all that sounds violent, the objects past Neptune may have had an even wilder shakeup.
不过，还不止于此。如果这些听起来都很跌宕起伏的话，那么经过海王星的物体分裂的情形可能更狂野。
Out there, objects have bizarre, irregular orbits, and generally aren't in the same plane as the planets.
海王星周围的物体都有着怪异的轨道，而且与其他行星也不再一个平面上。
But, if we trust the nebular model, and believe they evolved out of the same disk as Earth, something must have happened to make them that way.
但如果我们假设星云假说为真并且相信它们都像地球一样从同一个圆盘演变出来的话，
Some researchers think they could have been stirred up by a passing star.
一些科学家认为，它们可能是受到某颗恒星经过的影响。
For a long time, the chances of that seemed nil.
很长时间以来，我们认为这种可能性几乎为零。
But in 2018, a group of researchers published a paper looking into it more.
但2018年的时候，一组科学家发表了一篇论文，进一步剖析了这个问题。
They knew that the Sun was born in a cluster of stars that split up after about 10 million years.
当时的他们知道太阳是在星团中产生的，星团大概在1000万年后分解。
So they created a model based on the Orion Nebular Cluster, a similar cluster thought to have at least as many stars as the one our Sun was born in.
于是，他们根据猎户座星团制作了一个模型，这个模型是一个与猎户座星团类似的星团，其中恒星的数量与太阳诞生的星团差不多。
After running simulations on it, they made the case that during those early years, the probability of a star passing nearly as close Pluto was more like 20 or 30 percent.
在进行了多次模拟后，他们认为在早年间，一颗贴近冥王星飞过的恒星发生的概率在20%-30%。
And that could have easily scattered objects into the orbits we see today.
这样就能轻而易举地将物体分散到我们今天看到的各个轨道中。
Finding the answers to these questions is important for understanding our origins, but not just in a we seek to understand the cosmos kind of way.
找到这些问题的答案对于了解我们的来源很重要，而不只是为了了解宇宙。
Whatever happened in the early solar system is a big part of the reason that Earth exists, and that it's in just the right orbit for life.
无论早期的太阳系发生了什么，都是地球存在的重要基础，也是地球步入可孕育生命轨道的开始。
So if we understand how the solar system got the way that it is, we can use that information to figure out how many other systems might have planets like ours, or why they don't.
所以如果我们能解开太阳系如何形成的谜题，我们就能通过这些信息来弄清楚还有多少其他星系中可能有与地球类似的星体或者为什么没有与地球类似的星体。
And who knows? Maybe one day, we'll discover another solar system that's weird in all the right ways.
谁知道呢，或许某一天，我们会发现另一个太阳系，而它其各项特征也都怪异的很。
Thanks for watching this episode of SciShow Space!
感谢收看本期的《太空科学秀》！
You know, over the last few years, we've made more than 500 videos, because there's a lot to say and a lot to explore out there.
过去几年间，我们制作了500多个视频，因为有很多可以分享和探索的知识。
If you haven't any questions we haven't answered, though, we'd love to hear from you.
如果有未尽之处，希望听到大家的反馈。
So feel free to leave your suggestions in the comments, and we'll consider them for a future video.
请大家在评论区留言，我们会在今后的节目中考虑大家的建议。
