(单词翻译:单击)
Astronomers are always finding weird stuff in the universe.
天文学家们总是在宇宙中发现奇怪的物质。
But sometimes, their discoveries are especially strange and maybe a little spooky.
但有时，它们的发现非常奇怪，甚至有点儿可怕。
According to a paper published last week in Nature,
据上周发表在《自然》杂志上的一篇论文所说，
astronomers have found a star about 500 million light years away that just won't quit.
天文学家发现了一颗大约5亿光年远、不会终结的恒星。
It appears to have died and come back to life multiple times, almost like a zombie star.
它似乎已经死亡并复活多次，就像一颗僵尸恒星。
When really large stars run out of fuel, they can explode in gigantic, beautiful explosions called supernova.
大恒星燃料用尽时，会发生美丽的巨大爆炸，叫做超新星爆炸。
And scientists can describe them using graphs called light curves.
科学家们用“光变曲线”来描述它们。
A light curve shows you how bright an object is over some amount of time.
光变曲线表示的是物体在一定时间内的亮度。
For a supernova, the curve should look really bright at first, because it's exploding,
对于超新星来说，光变曲线起初因为爆炸应该看起来很亮，
and then it should taper off as everything disperses and cools.
然后随着物质分散和冷却应该逐渐消失。
Normally, a supernova doesn't stay bright for long: only about 100 days.
正常情况下，超新星的亮度不会持续太长时间，仅有100天而已。
And it only happens once because, well, the star is dead after that.
而且仅有一次，因为恒星爆炸之后会死亡。
But the light curve for this new supernova, called iPTF14hls,
但这颗超新星的光变曲线iPTF14hls，
which is so easy to remember, has all kinds of fun bumps in it, like it's pulsing.
很容易记住，它有各种各样有趣的波峰，就像它在跳动。
And even though we discovered it in 2014, it's still really bright three years later.
我们是在2014年发现它的，但三年后它仍然很亮。
It's also way brighter than your average, garden-variety supernova!
而且比普通的超新星亮得多。
So far, we've recorded it being almost 3.5 billion times as bright as the sun,
到目前为止，我们记录了它的亮度几乎是太阳的35亿倍，
while regular supernova usually aren't more than 500 million times brighter.
而普通的超新星绝通常不超过5亿倍。
But the weirdest part is that this object might have exploded before!
但最奇怪的地方是这个天体之前可能爆发过！
After seeing how strange it was, the team searched through previous research for similar phenomena,
研究小组在了解它的奇怪之处后，通过对先前类似现象的研究，
and they found an explosion recorded in the same spot in 1954!
发现1954年在同一地点有爆炸发生。
So, it seems like the star died about 60 years ago, but then made a comeback and exploded again.
所以，这颗恒星似乎在60年前就死了，但后来又卷土重来，再次爆发。
Right now, there isn't a full explanation for its behavior,
现在，人们对它的表现没有充分的解释，
but part of it may have to do with its mass.
但一部分原因可能与它的质量有关。
The team calculated that, before it exploded,
研究小组在它爆炸前计算过，
the star was at least 50 times the mass of the sun, and probably a lot bigger than it.
这颗恒星的质量至少是太阳的50倍，甚至可能更大。
And even though we've found thousands of supernova,
尽管我们发现了数千颗超新星，
we haven't yet seen a star that big die, so it could work differently than expected.
但还没见过一颗这么大的恒星死亡，所以它的工作原理可能和预期不同。
Another even cooler option is that this may be the first recorded pulsational pair-instability supernova, or PPISN.
另一种可能是它是第一个有记录的“脉动”不稳定对超新星（PPISN）。
This is something scientists have modeled, but never observed in real life.
科学家们建过这样的模型，但在现实生活中却从未观察到。
The idea is that, a star that's massive and hot enough might start manufacturing pairs of electrons
意思是说一颗巨大且热量充足的恒星可能会开始制造电子对，
and their antimatter opposite, positively-charged particles called positrons.
它们的反物质对立，带正电荷的粒子称为正电子。
And creating these pairs might drive the supernova's weird pulses,
创造这些电子对可能会导致超新星的怪异脉冲，
making them uses up energy that the star would normally use to stop itself from collapsing.
制造它们消耗的能量是恒星正常情况下用于阻止自身坍缩的能量。
But since it is used up, the star contracts.
但一旦能量用光，恒星就会收缩。
That causes more elements to burn in the star's core,
这会导致更多的元素在恒星核心燃烧，
which gives off a bunch of extra light, until the star eventually cools down and expands.
释放出一堆额外的光，直至恒星最终完全冷却膨胀。
And then the cycle begins again. So, more pulses.
然后循环再次开始。所以会有更多的脉冲。
Still, the team doesn't think a PPISN could fully explain what's happening,
但研究小组仍然认为PPISN仍不能完全解释这颗超新星的行为，
because we think those supernova get rid of most of their hydrogen early on,
因为我们认为这些超新星在早期就摆脱掉了大部分氢，
while this one has lots of hydrogen leftover.
然而这颗恒星上还有很多氢。
Plus, in this recent explosion, the mystery supernova has about ten times more energy than what PPISNs should.
而且，在最近的爆炸中，这颗神秘超新星的能量大约是PPISNs的10倍。
So it remains under close observation!
所以，它仍需进一步观察！
This week, astronomers reported another mystery in the journal Nature,
这周，天文学家在《自然》杂志上报道了另一个谜团，
but this time, it was about Pluto, and they've solved it!
但这次是关于冥王星的，他们解决了这个问题！
As it turns out, Pluto is super cold, which believe it or not, is unexpected.
事实证明，冥王星超级寒冷，甚至超出预期，不管你相不相信。
Okay, we already knew it must be kinda cold, because it's tiny and billions of kilometers from the sun.
好了，我们知道它一定很冷，因为它很小，又距离太阳数十亿公里。
But after New Horizons flew by in 2015,
但“新视野”号在2015年经过它时，
we found that it's about 40 degrees Celsius cooler than we thought.
我们发现它的温度与预期还要低40摄氏度。
According to new research, that's probably because it has a unique atmosphere.
根据最新研究，这可能是由于它的奇特大气导致的。
Studying an object's atmosphere is crucial to understanding its temperature,
研究天体的大气对于理解它的气温非常重要，
because atmospheres are normally fluffy, regulating planetary blankets.
因为大气层就像是调节行星气温的蓬松“毯子”。
On most planets, it's the gases in the atmosphere that do the regulating,
大多数行星依靠大气中的气体调节温度，
like how carbon dioxide influences Earth's temperature.
比如二氧化碳影响地球的气温。
But on Pluto, it's not the gases, it's haze, or something a little like smog.
但在冥王星上，不是气体影响气温，而是烟雾，它有点儿像烟。
From previous research, we already knew that Pluto has a somewhat hazy atmosphere,
我们从之前的研究中得知冥王星有薄雾一样的大气层，
because light passing close to its surface was dimmer than we'd expect.
因为光线从其表面经过时比我们想象的要暗淡。
New Horizons confirmed that, but it also found that the hazes are more abundant and stretch higher than we thought:
“新视野”号确认了这一点，但同时发现烟雾比我们想象中的更浓，延展地更高：
about 700 kilometers above the surface.
大约从其表面延伸至了700千米处。
Still, that didn't explain why Pluto is so cold.
这仍不能解释冥王星为什么这么冷。
But before we could learn more, New Horizons flew off farther into the Kuiper Belt,
但在我们了解更多消息之前，“新视野”号已经飞往柯伊伯带了，
so we couldn't gather the data to explore this temperature problem.
所以我们不能收集数据继续探索这个气温问题了。
And that's where modeling stepped in.
这就要建造模型了。
A team of scientists built a new and improved model of Pluto's atmosphere, and they found that,
一组科学家建立了一个新的、改进的冥王星大气模型，他们发现，
if they set it up so that hazes were the main thing controlling Pluto's temperature,
如果他们假设烟雾是控制冥王星气温的主要因素，
the model matched the New Horizons data!
这个模型就符合“新视野”号的数据！
In other words, Pluto's atmospheric hazes are mainly what's making it so cold, not its gases.
换句话说，冥王星的大气烟雾是造成其寒冷的主要原因，而不是气体。
That haze is likely made of lots of bigger hydrocarbons,
这种烟雾可能是由大量更大的碳氢化合物构成的，
which formed when light drove certain chemical reactions, a lot like how smog can form on Earth.
即光催化了某些化学反应形成的，非常类似于地球上烟雾的形成。
Those molecules are really great at sucking up energy,
这些分子非常擅长吸收能量，
but they're also great at radiating it away.
而且它们也擅长把能量辐射出去。
The hydrocarbons distribute the heat among themselves really rapidly,
碳氢化合物非常迅速地分散热量，
then force a lot of that heat into the upper atmosphere, where it spreads into space.
然后将大量的热量带到上层大气，扩散到太空中。
And that leaves Pluto extra chilly.
这就使得冥王星极其寒冷。
As far as we know, the only place in the solar system with a temperature controlled by hazes like this is Pluto!
就我们所知，太阳系中唯一一个由烟雾控制气温的星球就是冥王星！
And since hazes seem to play an important role in the atmosphere of some exoplanets,
因为烟雾在某些系外行星中扮演着重要角色，
this research might also help us explore worlds farther away.
这个研究可能帮助我们探索更远的世界。
That little dwarf planet just keeps impressing us!
那颗小矮星让我们印象深刻！
So this week, all kinds of expectations are being thrown overboard in the solar system!
所以，本周我们期待的都是太阳系的消息！
And I'm sure that is not the last time I'll say that.
我保证这不是最后一次这样说。
Thanks for watching this episode of SciShow Space!
感谢您收看本期的太空科学秀！
If you'd like to keep up with the latest news from around the universe,
如果你想继续关注宇宙的最新新闻，
you can go to youtube.com/scishowspace and subscribe.
就登陆youtube.com/scishowspace点击订阅吧！
