(单词翻译:单击)
It's been all over the internet lately:
最近有个消息风靡网络：
Astronomers discover that the sun has an evil twin! And that's what killed the dinosaurs!
天文学家发现太阳有一个邪恶的孪生兄弟，就是它杀死了恐龙！
Which would be an incredible discovery...if it were true.
如果消息属实的话，将会是一个令人难以置信的发现。
These articles are based on a paper that was published last month in the Monthly Notices of the Royal Astronomical Society,
这些文章基于上个月在皇家天文学会月刊上发表的一篇论文，
where researchers predicted that every star could've started with a partner, like in a binary star system,
论文称研究人员预测，每颗恒星开始时都有一个伙伴，就像双子星系一样，
and that most pairs just split up as time goes on.
大部分双星都随着时间的推移而分开。
Which means that our very own sun might have a long-lost sibling out there somewhere in the Milky Way.
这意味着我们的太阳可能在银河系的某个角落有一个失散多年的兄弟姐妹。
But we haven't actually found that sibling.
但我们确实没有发现它。
And even if this other star is out there, it isn't what killed the dinosaurs.
而即使另一个恒星在那里，它也不是恐龙灭绝的原因。
This is just one of those cases where people have gotten a little carried away with their headlines.
这只是标题党的一个例子。
So, let's start with the facts.
所以，我们开始阐述事实吧。
A lot of stars are singletons like our sun: They're on their own, with no nearby stellar neighbors to keep them company.
许多恒星和太阳一样都是单身：它们靠自己，没有附近的恒星邻居来陪伴它们。
But astronomical surveys have found that tons of stars are in multi-star systems,
但天文调查发现，大量的恒星都存在于多星系中，
which happens when two or more stars form from the same cloud of gas and dust and keep orbiting together.
当两颗或更多的恒星脱胎于同一星云并一起在轨道上运行时，就会出现这种情况。
Until now, astronomers figured that most loner stars were always only children, while stars in multi-star systems had always had siblings.
到现在为止，天文学家认为，最孤独的恒星都是独生子女，而多星系的恒星都有兄弟姐妹。
The paper's authors wanted to learn more about how multi-star systems evolve over time,
论文作者想要更多地了解多星系是如何随着时间的推移而进化的，
so they observed 24 young, multi-star systems in the Perseus molecular cloud,
所以他们观察了英仙座分子云团的24个年轻的多星系。
a stellar nursery a few hundred light-years away that has lots of new stars.
英仙座是几百光年之外的恒星摇篮，有许多新星。
Most of the systems were binaries, with two stars.
大多数星系都是双星，有两颗恒星。
Astronomers have found that binary stars tend to be pretty far apart when they're young, and get closer together as they age.
天文学家已经发现，双星在年轻时往往相距很远，随着年龄的增长而逐渐靠近。
And that's exactly what the team saw in the Perseus star systems.
这正是研究团队在英仙座星系中看到的。
But they also found something interesting about the way that the binaries orbited each other at different points in their lives.
但他们也发现了一些有趣的事情，在双星的一生中，它们在不同的位置相互环绕。
Young binaries that were just a few hundred thousand years old, which practically makes them newborns to astronomers,
年轻的双星只有几十万岁，对天文学家来说，它们是新生儿，
tended to orbit in the same direction their parent clouds were spinning.
它们的轨道与母体云团的自转方向一致。
That's not too surprising: If they just formed, they should be moving the same way as whatever they formed from.
这并不奇怪：如果它们刚刚形成，肯定会和母体云团的运行方式一致。
But the fewer older binaries orbited in ways that were more random, and didn't really have anything to do with the way their clouds spun.
但较老双星的运行方式更随意些，与母体云团的运行方式没有任何联系。
So something had to have changed their orbits as they aged.
所以它们老化的过程中，肯定有什么改变了它们的轨道。
To figure out what might cause these trends, the team did what astronomers often do best: They turned to computer simulations.
为了找出导致这种趋势的原因，这个团队做了天文学家最擅长的事：求助于计算机模拟。
They simulated stars forming under lots of different conditions, but only two of the models they tried actually fit the data.
他们模拟了许多不同条件下形成的恒星，但尝试的模型中只有两种符合数据。
In both models, all stars had to form with a distant sibling,
在这两种模型中，所有的恒星都必须与一个遥远的兄弟姐妹一起形成。
instead of just some of them, and the orbits would naturally shrink as the stars aged.
轨道会随着恒星的老化而自然地缩小，而不是只有一部分缩小。
In the first model, about 60% of the time, something like another star would get too close, and its gravity would fling the siblings apart.
在第一个模型中，大约60%的时间里另一颗星星之类的东西会靠得太近，它的重力会把这对双星分开。
In the second model, the gas clouds around them would sometimes split into pieces and drag the stars apart.
在第二个模型中，它们周围的星云有时会分裂成碎片，把双星拽开。
Either way, these binaries would become single stars like our sun.
不管怎样，这些双星会变成像太阳一样的单星。
So if either model is right, that would mean that every star started with a sibling,
所以不管哪个模型正确，都意味着所有恒星都是从多星开始的，
and that loners like our sun lost their neighbors as they grew up.
它们成长的过程中，像太阳这样的单星失去了它们的邻居。
Still, the paper's based on pretty limited data, so we don't know for sure if every star actually does start with a sibling.
这篇论文的数据基础相当有限，所以我们也不知道是否每个恒星都是从多星开始的。
We'll have to wait and see if future observations match up.
我们还要继续等待，看看未来的观测结果是否符合。
But in the meantime, all of this has dredged up an old hypothesis about a brown dwarf star named Nemesis.
但与此同时，所有这一切让我们想起了一个以前的假设，它和一颗名为“复仇者”的褐矮星有关。
Some scientists over the last 50 years have claimed that astronomical events like the asteroid that killed the dinosaurs
在过去的50年里，一些科学家声称，像小行星杀死恐龙这样的天文事件
happen too regularly to be by chance, about once every 27 million years.
经常定期发生，大约每2700万年一次。
In the 1980s, that led astronomers to calculate that something like a brown dwarf,
这导致天文学家们在20世纪80年代计算出了褐矮星这样的东西，
a small, failed star that couldn't start a fusion reaction,
它是一种小型、无法启动聚变反应的天体，
could cause that pattern if it orbited the sun from about one and a half light-years away.
如果它在大约1.5光年远的地方绕太阳运行，可能会导致这种模式。
Its gravity could affect the orbits of things like asteroids and fling them toward Earth.
它的重力可能会影响小行星等天体的轨道，使它们冲向地球。
The researchers named this star Nemesis. Because every good star needs an archenemy.
研究人员命名这颗星星为“复仇者”，因为每一个行星都需要一个大敌。
So some people have been saying that this new paper proves that Nemesis has been out there,
所以有些人说，这篇新论文证明“复仇者”已经存在了，
causing chaos in the inner solar system since it formed four and a half billion years ago.
自45亿年前形成以来，在太阳系内部造成了混乱。
But that's not what it says. Like, at all.
但事实并非如此。
The models predict binaries either break up really early on or that their orbits shrink as they get older.
这些模型预测双星要么是早期分裂，要么是老化时轨道萎缩，
So, yeah: the sun might have once had a partner.
所以，太阳曾可能有过一个伙伴。
But if it did, they would've split billions of years ago, and they wouldn't be anywhere near each other now.
但如果真有的话，它们数十亿年前就分开了，而且现在不会相互靠近。
The confusion probably comes from people calling the long-lost partner from this paper Nemesis.
这种困惑可能来自于那些人，他们认为与太阳失散多年的伙伴就是这篇论文中的“复仇者”。
But again: this star doesn't fit the theory that a star might have killed the dinosaurs.
但是再强调一次，这颗星星并不符合星星可能杀死恐龙的理论。
Even if the sun's sibling was still around, it should be hundreds of times closer than the 1.5 light-years astronomers predicted back in the 80s.
即使太阳的兄弟姐妹还在附近，它应该要比天文学家在80年代预测的1.5光年近数百倍。
Which means we almost definitely would've seen it by now.
这就意味着我们到现在为止绝对看到过它。
But astronomers have searched incredibly carefully for Nemesis, and they've come up with a whole lot of nothing.
但是天文学家们非常小心地搜寻了“复仇者”，没有找出任何东西。
We just haven't found anything that big anywhere near us.
我们也没有在附近找到任何大型天体。
So it's no surprise that this new paper never mentions Nemesis.
所以，这篇新论文没有提到“复仇者”并不奇怪。
Because even though it makes for a great headline, it's just not relevant.
因为即使用它做大标题，也不相关。
Thanks for watching this episode of SciShow Space News.
感谢您收看本期的太空科学秀。
If you want to learn more about the latest in space research and missions,
如果你想了解更多最新的天空研究和任务，
you can go to youtube.com/scishowspace and subscribe.
可以登录youtube.com/scishowspace，点击订阅哦！
