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At first glance, the universe can seem pretty straightforward, like when it comes to dying stars.
第一次看宇宙的时候，可能觉得一眼就望到头了，就像恒星终会消亡一样。
According to the standard story, which matches most of what we see around us, small stars die relatively quietly, while big ones explode as supernovas.
标准的故事情节跟我们平日里见到的景象吻合——小恒星消亡的时候相对安静，而大恒星会发生超新星爆炸。
But while that sounds neat and tidy and all, the reality is, big stars are complicated.
听起来很简单，但事实是：大恒星有自己的复杂性。
In the last two weeks, a pair of papers in the journal Nature has helped us address two outstanding mysteries about these stellar giants: how they really die, and how big they can actually get.
在过去的2周里，《自然》杂志上发表了2篇文章，帮助我们解决了有关2个恒星的重大谜题，即恒星是如何消亡的？大到什么程度才会消亡呢？
Both papers remind us that, for as nice as it would be to have one clean set of rules to explain space, things aren't always that easy.
这2篇文章都提醒我们：虽然有一整套规则能解释宇宙中发生的事情会很好，但现实总是很骨感。
But they are way more interesting. The first paper was on hypernovas.
现实情况往往更有趣。这第一篇文章是关于超超新星的。
Kind of like some regular supernovas, hypernovas can form when a star's core collapses really quickly.
超超新星有点像有规律的超新星，超超新星形成的条件是：恒星内核快速崩塌。
But while supernovas form from stars a few times more massive than the Sun, hypernovas form from stars tens of times as massive.
虽然形成超新星的恒星要比太阳质量大几倍，但形成超超新星的恒星，其质量是太阳的数十倍。
That makes them much brighter, and they've produced some of the biggest explosions since the Big Bang.
因此，超超新星的亮度更高，也引发了自宇宙大爆炸以来规模最大的爆炸。
But there's also a lot we don't understand about them.
但对于超超新星，我们还是知之甚少。
For example, according to models, the gas near the star's poles should produce huge jets of radiation known as gamma-ray bursts, or GRBs.
比如，一些模型显示，恒星极点附近的气体应该会产生大量辐射，也就是伽马射线暴（GRB）。
Sometimes, we do see this happen. But we've also seen hypernovas without these bursts, and it's not super clear what's going on.
有时候，我们确实会观测到GRB。但也有一些超超新星是不会伴随GRB的，但目前还不清楚为何会如此。
Previous work has suggested this could be thanks to what's called a cocoon:
之前的研究表明这可能是因为茧星云——
a cloud of gas near a star's pole that's heated by a jet of GRB radiation.
一种气体云，出现在恒星极点附近，会受到GRB的辐射而升温。
Scientists hypothesize that some jets can punch through these cocoons, but others get absorbed and never make it out, which explains the missing gamma-rays.
科学家假设认为，一些气流会穿过这些茧星云，但还有一些气流会因被吸收而无法逃出，这也就能解释为何一些伽马射线会凭空消失。
The problem is, cocoons are notoriously hard to study, either because they're outshined by the GRB itself, or because we don't notice them in time.
问题在于：众所周知，研究茧星云的难度很高，因为GRB的亮度超过了茧星云，所以，我们无法及时观测到它。
So it's hard to figure out how true this hypothesis is, or to investigate it further.
所以很难得知这个假设的真实度，或者对它进一步研究。
That is where this new paper comes in.
这也是这篇新论文的切入点。
By studying a special hypernova observed in 2017, authors were able to look at this process in more detail than ever before.
通过研究2017年观测到的一次特殊超超新星，本文的几位作者以更加细致的角度观测了这次超超新星，超乎以往。
Their hypernova was special because it involved a pretty dim GRB.
这次超超新星很特别，因为其中有亮度微弱的GRB。
It was bright enough to detect, but it wasn't bright enough to outshine the cocoon, and that allowed the team to study the explosion within a day of it happening.
虽然亮度还不至于勘测不到，但还不足以亮过周围的茧星云，所以该研究组可以在超超新星发生的当天内研究其爆炸情况。
That turned out to be really helpful. For one thing, the results back up what we used to think about cocoons.
还真挺管用。一方面，研究结果支持了我们之前对于茧星云的看法。
In a model of their hypernova, the team saw the jet lost some of its energy to the gas, but not all of it.
在他们的超超新星模型中，该团队发现，一些气流的能量散失到了星云中，但并不是完全散失。
If it had been stronger, it probably would have punched all the way through.
如果力量再强些，就可能全部吸走了。
And if it had been weaker, it would likely have been absorbed, just like previous studies said would happen.
如果再弱些，可能还是会被吸走一部分，这一点，此前的一些研究已经验证过了。
Also, by analyzing the light from around the explosion, the team was able to tell us more about what these cocoons are actually like.
通过分析爆炸附近的光，该研究组也让我们了解到茧星云的更多情况。
They discovered that the gas was moving, like, almost ridiculously fast: Some materials were going up to a third the speed of light, which is faster than anything we've seen in similar explosions.
他们发现，茧星云的是在移动的，移速非常快：部分组成元素的移速已经达到光速的1/3，比我们在类似爆炸中观测到的速度都要快。
The gas also contained different elements during the first day of explosion than later on, things like iron, cobalt, and nickel.
茧星云在爆炸第一天含有的元素种类比之后都要多，比如铁、钴、镍。
One researcher suggested these elements were probably produced in the star's core as it collapsed.
一位研究人员表示，这些元素很有可能是恒星崩塌时内核产生的。
That means that, not only can studying cocoons tell us how these explosions work, but they can also tell us what it's like inside of them.
也就是说，研究茧星云不仅可以让我们了解爆炸的过程，也可以让我们了解爆炸时内核的样子。
And the best part? The researchers collected a ton of data, so there might be even more to learn.
最好的在于：研究人员收集了海量数据，可能教会我们什么。
But either way, this is a big step in the process of understanding how big stars die, and it has some researchers pretty excited.
但无论是哪一种，这都对于我们了解特大恒星消亡过程大有裨益，这让一些科学家颇为兴奋。
Of course, hypernovas, and the stars that cause them, can only get so big.
当然了，超超新星和引发超超新星的恒星必须是这么大。
That's because if too much gas falls together as a star is forming, the gas will heat up and push more gas away.
这是因为：恒星形成的过程中，大量气体会聚集在一起，在升温后，会驱赶走更多的气体。
That generally stops stars from getting much heavier than a couple hundred times the Sun's mass.
这样，恒星的质量就不会变为太阳的数百倍。
But that also poses a problem.
但这样会产生一个问题。
See, early galaxies had supermassive black holes at the center, just like today's galaxies do, that could have been millions or billions of times the Sun's mass.
早期的星系中心有特大质量的黑洞，就像今天的星系一样，其质量可能是太阳的数百万乃至数十亿倍。
But black holes generally form from dying stars, and then they grow when gas or stars fall into them.
但黑洞基本都是从消亡的恒星中形成的，然后他们会因吸入气体和恒星而长大。
So if early supermassive black holes were formed from stars only a couple hundred times the Sun's mass, there wouldn't have been enough time for them to get so big.
所以，如果早期特大质量的黑洞是从质量仅为太阳几百倍的恒星中形成的话，那么就没有时间变得那样大了。
Fortunately, a paper published this Wednesday is challenging some of those assumptions, by saying that the early universe totally could have produced stars that weren't just a measly hundred or so solar masses.
所幸，本周三发表的一篇论文质疑了其中一些假设。该论文指出，初期的宇宙产生的恒星，其质量可能不只是太阳的几百倍。
They could have been ten thousand solar masses.
而可能是太阳的一万倍。
To figure this out, the paper's authors simulated giant gas clouds starting about 200 million years after the Big Bang.
为了弄清这个问题，本文的几位作者模拟了大爆炸大概2亿年后的巨型气体云
As the clouds crashed into each other, they condensed into lots of different stars.
气体云在相互碰撞后，就浓缩成了许多不同的恒星。
But the biggest stars didn't form in the center of the action with the others.
但最大的恒星并不是在中央形成的。
They were out in, like, the countryside, or, at least the suburbs.
而是在郊区或者乡村形成的。
There, they could keep growing as gas clouds merged together, but their heat didn't get added to the heat from the other stars.
在这里，他们可以一直随着气体云的聚集而扩大，但并未被其他恒星吸走热量。
The more heat there is, the more pressure there is to push the extra gas away, so by staying out of that crowded environment, these stars could get huge.
热量越多，压力就越大，就能将多余的气体驱散开来。所以，远离了拥挤的环境，气体云反而更大。
Admittedly, these enormous stars were pretty rare, only two formed out of hundreds of cases, but that's still common enough to make supermassive black holes much less mysterious.
无可否认的是，这些巨大的恒星十分罕见，几百颗恒星里才有2颗左右。但即便如此少，它们的存在也足以让特大质量的黑洞变得不再那么神秘。
And thanks to research from the last few years, the team can even explain why we haven't seen enormous hypernovas from these giants.
多亏过去几年来的研究，该研究组甚至可以解释我们为何无法在这些超大星体中看到超超新星的原因。
Some extremely massive stars can skip the supernova entirely and collapse straight into black holes at the end of their lives.
一些质量尤为大的恒星可以直接跳过超新星的阶段，直接变成黑洞。
Other research has even suggested that big collections of gas could fall together in just the right way to skip the star stage, too.
还有一些研究表明，气体云以正确的方式聚集在一起也可以跳过恒星阶段。
They'd go straight from gas cloud to black hole.
可以直接从气体云变为黑洞。
The new simulations didn't get into whether either of these scenarios happened to the first monster stars.
这些新的模拟并不属于第一批恒星的情况。
But they do give us a pathway going from hydrogen to enormous black holes, which is exactly what we need if we're going to understand the earliest galaxies.
但确实给我们提供了方向，无论是氢还是巨大黑洞，这些对于我们理解初期的星系都是很重要的。
Thanks for watching this episode of SciShow Space, which is officially our 500th episode on this channel!
感谢收看本期的《太空科学秀》，这也是我们的第500期节目哦！
We started SciShow Space back in 2014, and we have loved getting to explore all of the mystery, discovery, and straight-up ridiculousness of the universe with you over the last five years.
这档节目是2014年创办的，在探索谜题与发现的过程中，我们一直都充满欢喜，感谢过去5年来，在探索宇宙新奇知识点的过程中大家的陪伴。
If you want to help us make our next 500 videos, you can check out patreon.com/scishow.
如果您想助力我做以后的视频，可以登录patreon.com/scishow。
And if you want to keep learning about space with us, and your place in it, just go to youtube.com/scishowspace to subscribe.
如果您想跟我们一起了解太空的知识以及您在这其中所起到的作用，可以订阅youtube.com/scishowspace to subscribe。
