(单词翻译:单击)
Thanks to Brilliant.org for supporting SciShow Space.
《太空科学秀》由Brilliant.org赞助播出。
Space is packed with all kinds of mysteries; that's part of what makes it cool.
宇宙充满了奥秘，这也是让它如此迷人的原因之一。
Some of those mysteries, though, are closer to home than others.
其中一些奥秘就在我们身边。
Like, here's a surprising one: We actually don't know where the Sun came from!
比如，有个奥秘说来令人吃惊：我们其实并不知道太阳是从何而来的！
According to what we know about star formation, the Sun probably formed from a huge cloud of gas, along with a bunch of stellar siblings, stars that formed in the same place out of the same stuff.
根据目前我们对恒星形成的所知，太阳很可能是从一大团气体云中形成的，此外还伴随着一些其他恒星。这些恒星跟太阳所出同处。
Except, we can't find evidence of that cloud, or the Sun's family, anywhere.
说是这样说，但我们找不到这样的气体云，也找不到太阳的兄弟恒星。
Our little Sun is all on its own. Get your tissues ready, because this is basically waiting to be turned into a Pixar short.
太阳是孤身一“人”的。不过，先别灰心，事情可能有反转。
Even though we can't find the Sun's family, we're pretty confident it has to exist because of how most stars form.
虽然我们找不到太阳的家人，但我们坚信太阳一定有家人，根据就是恒星的形成方式。
The current model requires that a bunch of stars get born together out of a big ol' gas cloud, called a molecular or giant molecular cloud depending on its size.
当前模型的前提是：一些恒星一起从大团气体云中出世，这团气体云又称分子云，如果体积庞大的话就叫巨型分子云。
Eventually, because space is super vicious, the clouds get eaten up or dispersed by their star children.
最后，宇宙变得极为复杂，气体云要么受到吞噬，要么被恒星驱散。
After that, the stars, and their planets, if they've accumulated any, might separate or might move together for a while in a so-called open cluster.
然后，恒星（如果有行星的话，也会带上行星）可能会分离，也可能会在所谓的疏散星团里一起移动。
Then, over time, all the little gravitational pulls and tugs from the member stars build up and finally send the stars on different trajectories.
然后，随着时间的流逝，各种万有引力的作用会聚在一起，最终让恒星走上了不同的轨道。
These stars can end up all over a galaxy, but they can still be identified as members of the same family because they typically have similar ages, and often have really similar compositions.
这些恒星可能会遍布整个星系，但他们依然是同一家族的成员，因为他们的年龄相仿，组成十分相近。
There can be plenty of variation within a cluster, but there are still some general trends we can look for.
同一个星团内会有不同的情况，但有一些大趋势可以把握。
Most stars don't stick around to form open clusters, but we have evidence that the Sun was one of the few who stayed with its family a bit longer.
大多数恒星在形成疏散星团之前就彼此分离了，但有证据表明，太阳就是为数不多的一颗与家族成员分隔时间较晚的恒星。
For one thing, the orbital motions of the Kuiper Belt objects, most notably the planetoid Sedna, strongly suggest some gravitational interaction with other stars, probably in a relatively dense group.
一方面，凯伯带里物体在轨道上的运行情况（最显著的要属小行星塞德娜）都大力证明了太阳与其他恒星之间的相互作用。而且这种相互作用很可能是在密度相对较大的星团中发生的。
Otherwise, they likely couldn't have been jostled into their current orbits.
否则，它们很可能不会出现在现在的轨道上。
There's also evidence, like the excess amount of heavy elements in the Sun, and the presence of uranium in the Earth, that there was a supernova near our star when it formed.
还有一些证据可以表明太阳形成的时候，其附近有超新星出现。这样的证据包括但不限于：太阳中含有大量重元素；地球中含有铀。
It could've come from a huge, short-lived member of a larger stellar nursery, like an older sibling who peaked too early.
太阳有可能来自于某个更大分子云中一个存活时间较短的大型恒星，像太阳英年早逝的一位兄长一样。
We have plenty of reason to believe that the Sun was born in an open cluster, but we can't find anyone else from that stellar nursery, even though we've been looking all over.
我们有充分的理由认为，太阳是在疏散星团中产生的，但我们费尽九牛二虎之力也没有找到太阳的兄弟姐妹。
It's like Finding Dory, but with a lot more math.
这个过程有点像《海底总动员2》，只是包含更多的数学计算。
For a while, astronomers thought the Messier 67 open cluster, or M67 for short, was the most likely candidate.
有一段时间，天文学家认为疏散星团M67是最有可能的候选对象。
It's an open cluster about 2700 light years away, in the Cancer constellation.
该星团距离我们有近2700光年的距离，位于巨蟹座中。
It's a pretty dense group, which would match our hypotheses, and it's also about five billion years old.
这是一个密度极高的青团，也印证了我们的假设，而且它已经有近50亿年的历史了。
That's really old for an open cluster, but it's about as old as the Sun!
这个年龄在疏散星团中算很大的了，几乎跟太阳差不多大！
Admittedly, dating stars is really hard, so there are some big error bars on that measurement.
无可否认的是：要确认恒星的年龄不是一件易事，所以在衡量过程中会有一些很大的误差棒。
But it's in the ballpark, and astronomers love ballparking.
但这件事情的可变通性正是天文学家喜闻乐见的。
So its age and density make M67 a good candidate, but its orbital path around the galaxy is way different from the Sun's, and that's become a big source of debate.
所以，其年龄和密度让M67成为了重要的候选对象，但M67在星系附近的轨道与太阳的迥然不同，这一点也成了争论的焦点。
On the one hand, this might not be a problem.
有的人认为，这可能不是个问题。
Because members of open clusters interact gravitationally, it's possible that a star could get kicked out and end up with some different orbital parameters.
因为疏散星团中的恒星会有相互作用力，所以有可能某颗恒星可能被“踢出局”，然后有了与其他恒星不同的轨道参数。
But on the other hand, the kind of kick that the Sun would have needed to get on its current path is super huge, like, too big for it to have kept its baby solar system.
但也有人认为，太阳进入目前轨道所需的作用力是非常大的，但尚处于婴儿时期的太阳如果受到了这样的作用力就可能会摧毁太阳系的稳定性。
So the fact that we're here is some evidence against the M67 hypothesis.
所以，既然人类能存在到今天就证明M67的假说有问题。
That is, unless that kick happened really early on.
除非这个作用力发生在很早很早的时候。
An early, gentle nudge, given a lot of time, could have gotten the Sun way off course.
当然了，如果有充足的时间，那么很早的时候，即便是不大的作用力也能让太阳改变轨道。
So, we're still not exactly sure what's going on here!
所以我们现在也不清楚到底是怎么回事。
What we could really use is more data.
我们只能搜集更多的数据。
Thankfully, there are a few projects, both launched in 2013, that are helping with that.
好在2013年发起的一些项目为我们提供了一些帮助。
One is the Gaia mission, run by the European Space Agency, and the other is the GALAH project, run by the Australian Astronomical Observatory.
其中一个是欧洲太空总署的盖亚任务，另一个是澳洲天文台的银河考古学调查(GALAH)项目。
Together, they're collecting astrometry and astrochemistry data of a truly enormous quantity of stars, or data about their positions, movements, and chemistry.
这两个项目收集了大量恒星的天体测量学数据和天体化学数据，比如它们的位置、移动情况和化学组成。
Astrometry is good for finding former and current open clusters, because members of them move together.
天体测量学有助于发现以前和现在的疏散星团，因为有一些会一起移动。
And even if the Sun's siblings have dispersed, we could use current star positions to calculate the cluster's original location.
即便太阳的兄弟姐妹们可能天各一方，但我们可以通过当前的恒星位置来计算出星团的原始位置。
Astrochemistry may also prove to be a smoking gun.
天体化学可能也会提供确凿的证据。
Since the Sun is so metallic from that supernova explosion, its sibling stars may have similarly high metallicities.
在超新星爆炸发生后，太阳的组成成分中含有许多金属物质，所以其兄弟行星的金属含量可能也会很高。
All we have to do is find stars that match those descriptions!
所以，我们只需要找到金属含量高的恒星即可！
Gaia is working to get astrometric and astrochemical data on a /billion/ stars from an orbit near Earth.
盖亚的任务是从地球附近的轨道上获取10亿颗恒星的天体测量学数据和天体化学数据。
GALAH, on the other hand, is just doing astrochemistry on a more modest million stars, and it's operating from the ground.
而银河考古学调查的测量范围更小一些——只有几百万个，是从地面上关注这些恒星的天体化学数据。
Both missions will wrap up over the next few years.
这两项任务会在几年内结束。
After that, it's up to astronomers to make sense of the mountains of data!
在那之后，就要由天文学家来分析海量数据背后的含义了！
Between the two surveys, we're characterizing tons and tons of stars.
通过这两项计划，我们会确定无数恒星的特征。
We haven't found the Sun's siblings yet, but these surveys are currently our best chance at it.
我们还没有找到太阳的兄弟恒星，但这两项任务是我们最好的机会了。
Besides being a nice end to a story, understanding where the Sun originated and what it was like there can also help us understand why our solar system turned out like it did.
调查不是目的，目的是了解太阳从何处而来以及起源地的样子，这也可以帮助我们理解太阳系为什么会是今天这个样子。
Still, even if these projects don't give us the data we need to solve the Sun's mystery, they'll give us incredible insights into the formation and evolution of the galaxy, which is a pretty sweet consolation prize.
所以，即便这两项任务提供的数据无法帮助我们揭开有关太阳的谜题，至少也能让我们更加了解太阳系的组成和演变，这也算有失有得。
But there are some puzzles we can solve about where stars come from on Brilliant.org.
但至于恒星是怎么来的，Brilliant.org上是有解答的。
That's right, they have a whole course on the Life Cycles of Stars which starts with this Star Formation quiz.
在这上面有一整套关于恒星生命周期的过程，课程开始之前要先做有关恒星形成的测试题。
What's cool about Brilliant is that they've really embraced how to best use their platform with animations that help you wrap your brain around a complex idea.
Brilliant的好处在于这个平台知道怎样通过动画以最好的方式来让人理解一件复杂的事情。
When I was going to school and regularly taking science quizzes, we didn't have the internet or computers in the classroom, because I'm old.
我上学的时候就不会进行常规的科学测试，那时候，我们的教室里没有互联网和计算机，毕竟我已经是个老人了。
We had this stuff called paper and it didn't include moving graphics like this that help you imagine the problem.
我们那时候只有论文可以借鉴，但论文是没有动画和图像的，所以不能帮助我们更好地想象某个问题。
But with Brilliant, whether you're a student or a lifelong learner, you can benefit from these interactive quizzes to help you learn and have fun while you're doing it.
但有Brilliant在手，无论你是学生，还是热衷于知识的学习者，你都可以通过互动的测试获益，在愉快的氛围里学到知识。
So check it out and see how much you know about star formation.
所以不妨尝试一下Brilliant，了解恒星形成的奥秘。
Brilliant is also offering 20% off their annual premium subscription to the first 200 SciShow Space viewers who sign up at Brilliant.org/SciShowSpace.
Brilliant还为前200名注册Brilliant.org/SciShowSpace的用户提供20%的订阅费减免。
So you'll get a discount, and be helping to support SciShow Space.
所以在得到优惠的同时，大家也支持了我们的节目。
So thanks! You are awesome!
提前谢过棒棒的你们！
