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When massive stars run out of fuel at the end of their lives, they die in fantastic explosions called supernovas.
大质量恒星终会因燃料耗尽而消亡。它们会在规模甚大的爆炸——超新星中消亡。
They're some of the biggest explosions out there, and they can shine as bright as an entire galaxy.
这是宇宙中规模最大的爆炸之一，其亮度不亚于一整个星系。
Most of them fit neatly into one of a few categories, depending on what they look like and what causes them.
大多数超新星过程都可以归为一些类别，归类的方式要取决于它们的样子和起因。
But then, there are the peculiars, a special group of supernovas that don't quite fit in with the rest.
但也有一些个例跟其他类型的超新星不同，十分特别。
These oddballs include failed explosions, extremely bright ones, slow ones, and a whole slew of other quirky stars.
比如，爆炸失败、亮度过高、爆炸缓慢等各种离奇的情况。
They're the ugly ducklings of the supernova family, but their weirdness is what makes them so valuable.
这些个例是超新星家族里的丑小鸭，但它们的怪异也让它们十分宝贵。
Here's what we've learned from three of them.
我们从其中3个怪异的超新星过程中学到了如下知识。
In 2014, astronomers discovered a supernova 300 million light-years away, and they gave it the charming name iPTF14atg.
2014年，天文学家发现了3亿光年外的一颗超新星。他们给它起了一个很酷的名字——iPTF14atg。
It was part of a class called type Ia supernovas, but it was a bit of a dud at first, kind of dim and slow.
这颗超新星名作Ia型超新星。一开始，它很不起眼，亮度不大，爆炸过程又十分缓慢。
Then, less than four days after the explosion, something really strange happened: It gave off a flash of ultraviolet light.
然后，在爆炸发生不到4天后，奇怪的事情出现了：它放出了一道紫外线。
No one had ever seen anything like it, but it offered a clue to a longstanding mystery.
这种景象见所未见，但却为我们揭开一个长时间的谜题提供了线索，
See, we still don't really know what causes this class of supernova.
因为我们并不知道这类超新星的类别。
One idea says that they form when two white dwarf stars collide.
有一个观点是：当两颗白矮星碰撞时，会形成这类超新星。
Another suggests that they happen when a white dwarf steals matter off a companion star, which is typically too dim to see.
还有人认为：但一颗白矮星从一颗伴星上吸取物质时会形成这类超新星，但这个过程十分晦暗，根本看不到。
Eventually, the dwarf acquires enough mass to set off a thermonuclear reaction, and blasts itself to pieces.
最后，白矮星会吸取足够的物质，并引发热核反应，将自己撕裂成碎片。
It's really hard to pin down the true origin story, because by the time a supernova catches anyone's eye, it's already blown itself up, and destroyed the evidence.
很难确定最初的情况，因为当我们看到某个超新星时，这颗恒星已经四分五裂，证据也都消失殆尽了。
But the 2014 discovery helped shed light on things.
但2014年的这项发现助力我们了解了一些情况。
Before this, scientists thought that if a supernova did have a companion star, its debris should slam into that surviving companion at some point.
在此之前，科学家认为：如果一颗超新星有伴星，那么其残骸就会在某个时间点与尚未消亡的伴星发生碰撞。
When it did, researchers predicted that collision would heat up nearby material so much that it would create a flash of ultraviolet light.
到这步之后，研究人员预测认为：碰撞的过程会导致附近的材质极度升温，从而产生紫外线。
So when they saw that flash for the first time in 2014, it seemed like the case was closed: Type Ia supernovas happen in stars with companions, not in collisions.
所以，他们2014年第一次看到这束紫外线时，仿佛已经解决了这个问题：Ia型超新星会在有伴星的恒星中产生，而非通过碰撞产生。
Everybody can go home now!
大家可以洗洗睡啦！
Except, another team disagreed.
但还有一个研究小组不认同这个观点。
When they looked at data from three similar supernovas, they didn't find that ultraviolet spike.
该研究组查看了3个类似的超新星数据，但他们并未发现这种紫外线。
Meaning those stars probably didn't have companions.
也就是说，这些恒星很有可能没有伴星。
That kind of threw a wrench in things, but now, after more research, astronomers think type Ia supernovas probably form in at least two totally different ways.
曾几何时，这个问题看起来只有一个答案，但经过多方调研后，天文学家认为，Ia型超新星很有可能至少有2种完全不同的形成方式。
Some may feed off a companion, like the 2014 discovery, while others may come from the merger of two stars.
有些超新星会吸取伴星的物质，比如2014年的发现成果；但还有些超新星是来自2颗恒星的合并。
We're still pinning down exactly how all this works, but it's no wonder this question has been so hard to figure out!
我们目前还在确定超新星形成的过程，但这个问题还是很难解决的。
Our next oddball supernova was spotted in 2006, and it was the brightest one astronomers had ever seen.
第二个怪异的超新星是在2006年发现的，这是科学家观测到过的最亮的一颗。
It was a peculiar called SN 2006gy, and it exploded 240 million light-years away with 100 times the energy of an ordinary supernova.
它与众不同，名为SN 2006gy。它在离我们2.4亿光年的地方爆炸了，释放出的能量是普通超新星的100倍。
And while typical explosions fade after about half a year, this one didn't.
一般爆炸大概需要半年的时间就能完成，但这颗超新星却不是。
Eight months after its detection, it was still outshining normal supernovas at their peak.
在我们发现它之后过了8个月，它依然比正常的超新星最亮时还要亮。
Astronomers figured that the star that blew up must have been a monster, around 150 times the mass of our Sun.
科学家认为，爆炸的那颗恒星一定不可小觑，质量是太阳的近150倍。
Stars this massive are super rare in today's universe.
质量如此大的恒星在今天的宇宙里是极为稀少的。
There are maybe a dozen of them among the Milky Way's 400 billion stars, but that wasn't always the case.
银河系的4000亿颗恒星里，或许有10多颗这样的恒星，但这并不是问题的关键。
The first stars in the universe were likely all giants, which meant 2006gy could help us understand how they died.
宇宙里的第一批恒星很有可能质量都很大，也就是说，2006gy或许可以帮助我们了解宇宙中第一批恒星是如何消亡的。
Before this, scientists believed huge stars could skip the supernova stage entirely, and collapse directly into black holes.
在此之前，科学家认为大质量恒星不存在超新星阶段，会直接变为黑洞。
But 2006gy suggested that, instead, these giants spewed their materials back into space in some of the most spectacular and energetic events ever.
但2006gy的出现表明，这些大质量恒星会将组成它们的材质释放回宇宙中，其释放过程伴随着巨大能量。
That could mean these early stars played an important role in filling the universe with different elements, which make up everything in our solar system, including us.
这可能意味着早期的恒星对于为宇宙提供不同的元素起到了重要的作用，从而组成了太阳系里的一切事物，包括人类。
So thanks for sharing, giant stars!
所以，我们要感谢大质量恒星的自我分享。
And that brings us to our final peculiar supernova, called SN 2005E.
下面介绍第3个奇异的超新星，名作SN 2005E。
Astronomers spotted it in 2005, 100 million light-years away.
天文学家是在2005年发现它的，它距离我们有1亿光年的距离。
It blew up in the outskirts of its galaxy, where stars rarely form.
它爆炸的地方是其所在星系的外围，那里几乎没有什么恒星形成。
It was also about 100 times fainter than a typical supernova, and it faded really quickly.
其亮度是正常超新星的近1/100，而且消散地极快。
But strangest of all, almost half of the stuff it ejected was calcium.
但最怪异的是：其释放出的物质中，近一般都是钙。
It spit out between 5 and 10 times as much of it as a normal supernova.
其释放出的钙是正常超新星的5-10倍。
Today, we think that's because it was stealing matter from a companion star.
如今，我们认为其原因是它从伴星上吸取了物质。
But instead of stealing hydrogen like in typical supernovas, it was stealing helium from a star with helium in its outer layer, possibly another white dwarf.
但它吸取的并不是常规超新星吸取的氢，而是从另一颗恒星的外层吸取了氦，而另一颗恒星很有可能就是一颗白矮星。
When that gas ignited, it produced large amounts of calcium, along with other elements like titanium.
当氦气点燃后，会释放出大量钙，还有其他元素，比如钛。
This discovery turned out to be really important, because it helped astronomers figure out why there's so much calcium in the galaxy in the first place.
这一发现非常重要，因为它帮助天文学家弄清楚了银河系里为何有如此多的钙。
Calcium is the fifth-most common element in Earth's crust, and the Milky Way is full of it.
钙是地壳中含量第5高的元素，银河系里到处都是钙。
But for a long time, scientists didn't understand why.
但很长时间以来，科学家并不知道原因。
Their models predicted there should be 50% less of it than what they actually observed.
他们的模型曾预测认为：钙的含量应该是实际观测到的50%。
The problem was, those models were based on the fact that almost all elements form in stars or supernovas.
问题在于：这些模型所基于的事实是——几乎所有元素都会形成恒星或者超新星。
And they didn't include supernovas like 2005E, because we hadn't found them yet!
但他们却没有考虑2005E这样的超新星，因为我们当时还没发现！
This explosion was unusual at the time, but over the next five years, astronomers found seven more that looked like it.
这次爆炸也很不寻常，但在未来5年间，天文学家又发现了7个类似的超新星爆炸。
They realized that this appeared to be a new subcategory, and we can likely thank these supernovas for all that extra calcium in the universe, and for the stuff in our bones.
他们意识到这似乎是一个新的子类，我们很有可能要感谢这些超新星为宇宙增加了如此多的钙，而钙又是人体骨骼的重要组成部分。
In the end, we have peculiar supernovas to thank for a lot more than our calcium.
最后，还有一些独特的超新星要感谢，它们比钙还要重要。
These rule-breakers force scientists to question and sharpen their best hypotheses.
这些不走寻常路的存在让科学家发问，并不断精进最佳假设。
They also offer hints about what death was like in the early universe, and they tell us that giant stars die in really different and spectacular ways.
它们还有助于我们了解宇宙初期的消亡过程是怎样的，告诉我们大质量恒星的消亡可以有各种新奇的方式，
It just goes to show that fitting in and being predictable is totally overrated.
同时也展示了永远让人猜不到才是独特的方式。
Thanks for watching this episode of SciShow Space, and a special thanks to our patrons on Patreon!
感谢收看本期的《太空科学秀》，尤其要感谢我们的忠实粉丝。
There's so much cool stuff to learn about in the universe, and we couldn't cover it without your help.
宇宙里有很多奇特的事情可以学习，如果没有你们的支持，我们就无法一一尽述。
If you want to help us keep exploring space and making free educational videos, you can go to patreon.com/scishow.
如果大家想帮助我们探索宇宙并制作免费的教育类食品，可以登录patreon.com/scishow。
