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When you look up on a clear night, virtually all of the stars you can see are part of the Milky Way.
我们抬头仰望晴朗的夜空时，我们能看到的所有星星其实都是银河系的一部分。
Even the farthest one you can find without a telescope is less than 20,000 light-years from you.
我们肉眼能看到的最远的星星，距离我们也不过2万光年。
That might seem really far away, and yeah it is, but space is way bigger than our little neighborhood.
2万光年，听起来很远很远，事实也确实如此，但太空要比我们的小小银河系大多了。
It's so huge that it's hard to study the billions of stars outside the Milky Way.
太空大到什么程度呢？大到我们很难研究银河系之外的星星。
In fact, the farthest star we've isolated is in a galaxy only 55 million light-years away. At least, that's what used to be true.
实际上，我们能锁定的最远的星星距离我们也不过5500万光年，至少，以前是这样的。
According to a paper published this week in Nature Astronomy, that record was blown out of the water.
不过，根据本周《自然-天文学》上发表的一篇论文，这个纪录已经被远远地甩在了后面。
Now, the most distant single star we've ever seen is 14 billion light-years from us! Yeah, billion. With a B.
现在，我们能锁定的最远的星星距离我们有140亿光年，你没听错，单位是亿。
In general, it's not that uncommon for astronomers to observe faraway objects.
总体而言，天文学家观测到遥远星体的事也是比较常见的。
For example, with telescopes, they can see the brightest supernovas up to 10 billion light-years away.
比如，通过使用望远镜，他们就能看到100亿光年远的最亮的超新星。
But individual stars are normally impossible to make out even a hundred times closer than that. Unless they're gravitationally lensed.
但对于单个的恒星来说，正常情况下，即便他们距离我们更近100倍，也很难辨认出来，除非有引力透镜的作用。
This is what happens when a large amount of mass, like a galaxy,
比如，大质量物体，比如一个星系
or an entire cluster of galaxies, bends, distorts, and magnifies the light from objects behind them.
或者几个星系的集合发生弯曲、变形，放大了它们背后物体发出的光。
It's a phenomenon that happens because objects with a lot of mass actually distort the space around them.
这种情况确实存在，因为大质量物体会使周围的时空发生扭曲。
On average, galaxies experiencing gravitational lensing get magnified about 50 times their normal brightness.
一般情况下，经历引力透镜的星系，其亮度是正常情况的近50倍。
But this new star, which was found behind a galaxy cluster around six billion light-years away from here, got magnified 2000 times!
但我们又发现了一颗恒星，这颗恒星位于一个星系集合的后面，这个星系集合距离地球有60亿光年远。就是在这样的情况下，这颗恒星的亮度放大了2000倍。
That star's name is officially MACS J1149 Lensed Star 1. But the team that found it unofficially calls it Icarus. Thank you, astronomers!
这颗恒星的官方名字是MACS J1149 Lensed Star 1，但发现它的小组私下称它为伊卡洛斯，这里要感谢各位天文学家的工作！
Scientists first found Icarus almost by accident, when they were studying images of a supernova the Hubble Space Telescope took in 2016 and 17.
科学家首次发现伊卡洛斯是在意外的情况下，那时候他们正在研究一个超新星的图像。这些图像是哈勃望远镜在2016和2017年拍到的。
While studying the pictures, they noticed a second bright spot not too far away.
在研究这些图像时，他们注意到不远处有一个亮度稍稍逊色的点。
It was also varying in brightness over time, but not the way that supernovas do.
这个点的亮度会随着时间而变化，但变化规律并不与超新星相同。
Specifically, the colors of light coming from it didn't change over the months of observation.
准确来说，这个点发出的光色在观察的几个月里都未发生改变。
Further analysis of those colors revealed the object was a blue supergiant.
进一步分析光色发现，这个物体是一颗蓝色超大星。
These are stars much larger, more massive, hotter, and up to hundreds of thousands of times brighter than our Sun.
这种恒星体积和质量更大、温度更高，亮度是太阳的几十万倍。
You know, just in case you needed another reminder that space is pretty hardcore.
说这个只是不想让大家误解，以为宇宙不过须臾之地。
All blue supergiants have similar profiles, so by comparing Icarus's light against stars in our galaxy, the astronomers were able to calculate its distance.
所有蓝色超大星的范式都十分类似，所以通过比较伊卡洛斯和银河系里恒星的亮度，天文学家就能计算出伊卡洛斯离我们有多远。
They found that the light it's emitting is 9 billion years old, and because the universe is expanding, that puts it about 14 billion light-years from us.
天文学家发现，这颗蓝色超大星的光是90亿年前发出的，而且由于宇宙是不断扩张的，据此可以推测它距离我们大概有140亿光年。
But how did Icarus manage to be magnified 2000 times, when the regular amount from gravitational lensing is a measly 50?
正常情况下，引力透镜只能实现50倍的亮度增强，那伊卡洛斯的亮度是如何增强到2000倍的呢？
The answer is microlenses, small objects within the larger lens, like individual stars, that provide their own additional magnification.
答案是微引力透镜，体积小的物体在更大的透镜下，比如单独的恒星，就能实现额外的亮度增强。
Lenses within lenses. That boost is only temporary, because the microlenses will constantly be moving into and out of alignment.
也就是“镜中镜”，这种亮度的增强只是暂时的，因为微引力透镜会不停地进去再出来。
But if the timing's right, the effect is massive. Microlensing has even been used to find exoplanets outside the Milky Way!
但如果时间恰好，效果会是巨大的，天文学家还通过微引力透镜来寻找银河系外的外星行星。
Icarus isn't just a star for the record books, either. By studying the pattern by which it gets magnified over time,
伊卡洛斯也不只是史书上才有的东西，通过研究其亮度增强的模式，
astronomers will be able to model exactly how matter is distributed in the lensing galaxy.
天文学家也可以建模出透镜星系中的质量是如何分布的。
That includes its mysterious dark matter, which we can't see but which has gravitational effects on other bodies.
这其中也包括神秘的暗物质，虽然我们看不见它，但它对其他星体有引力作用。
So besides smashing records, Icarus probably has a lot more to teach us. In other news announced this week, the Milky Way might be getting bigger.
所以除了让我们大开眼界以外，伊卡洛斯能教我的还有很多，下面介绍下本周的其他新闻：银河系可能正在变得越来越大。
At least that's what astronomers presented this week at the European Week of Astronomy and Space Science in Liverpool.
至少一些天文学家在利物浦的《欧洲天文与空间科学周刊》上是这样写的。
Our galaxy has been around for a while, and it's grown as new stars formed over millions and billions of years.
银河系已经陪伴我们许久了，而在这段时间里，它也随着新星体的形成而逐渐壮大。
Previous work has shown that stars of different ages now exist in different parts of the galaxy.
之前的研究工作已经表明，不同年代的星体现在处于银河系的不同部分。
For example, in the central bulge and galactic halo, there are lots of older stars, because there isn't much raw material left there to make newer ones.
比如，在中央凸起处以及银河系的光晕处就有很多年代久远的星体，因为那里没有足够的原材料，所以无法形成新的星体。
Meanwhile, in the outer edge of our galaxy's disk, studies have identified star-forming regions where baby stars form all the time.
与此同时，有研究发现，银河系的外围有形成星体的区域，那里一直都有新的星体诞生。
And general models for galactic evolution suggest that the new stars in these regions will slowly cause the galaxy to grow.
而且银河系演变的一般模型都显示，该区域新诞生的星体会慢慢壮大银河系。
If you think about, it makes sense. It's like a city growing because people keep building new neighborhoods on the outskirts of town.
细细想来，也有道理，这就像城市随着郊区街区的增多而变大。
Still, it's hard to actually study this happening in the Milky Way, cause we're kinda stuck inside of it.
不过，目前还很难研究银河系里新星诞生的发生情况，因为我们有点困于此了。
To get around that, a team of astronomers studied two other galaxies that might have similar spiral structures to ours.
为了解决这个问题，一组天文学家研究了另外两个星系，这两个星系与银河系有相似的旋涡结构。
If these galaxies seem to be getting bigger from star formation at their outer edge, then it's not unreasonable to infer that the Milky Way is, too.
如果这些星系也会因为外围新星体的形成而变大的话，那么银河系就不应该是这样了。
By collecting optical, ultraviolet, and infrared data of young, blue stars in these galaxies' outer disks, scientists were able to calculate their vertical movement, how much they were moving up and down compared to the disk.
通过收集这两个星系中年轻蓝色星体的光学数据、紫外数据、红外数据，天文学家就能计算出他们的垂直移动，以及移动幅度。
Then, they could convert that into a galactic growth rate.
然后，他们可以借助这些数据得出银河系的扩张速率。
These stars appeared to have velocities of about 500 meters per second, so the Milky Way could be growing at that same rate.
这些星体的速率大概500m/s，所以银河系的扩张速率也是如此。
That seems pretty fast, but it's really not too speedy on a galactic scale. In about 3 billion years, it means our neighborhood would only have grown by 5%.
这个速率听起来很快，但就银河系的体量而言，就不是很快了，就相当于在大约30亿年的时间里，银河系的扩张速率大概只有5%。
Then again, that growth rate might be completely messed up by then, because our galaxy will collide with Andromeda in about 4 billion years.
不过，这个扩张速率之后可能就不是这个节奏了，因为银河系在大概40亿年后会与仙女座相撞。
But hey, no matter what happens, studying how galaxies grow still helps us better understand the universe.
不过，先别想那些呀，毕竟研究各种星系的成长会帮助我们更好地理解宇宙。
Because even though the Milky Way is our home, there's a whole lot we don't totally understand about our corner of space.
因为虽然我们生活在银河系，但即便对宇宙里的这个冰山一角，我们也没有了解得十分透彻。
But that doesn't mean that there's not a ton to celebrate about our corner of space!
但对于银河系，我们还是有很多值得庆祝的地方。
We recently restocked SciShow Finds, which is a site filled with objects that we curated from this lovely planet of ours.
最近我们又在太空科学秀的发现频道新增了许多集锦，内容都与可爱的银河系有关。
So if you need the most powerful refrigerator magnets in existence, or a science lab you can carry around in your pocket, or just a reminder that honeybees are really great, you can go to scishowfinds.com,
所以，无论您是需要强力冰箱贴，还是可以随时携带的科学实验室，亦或只是单纯想提醒自己蜜蜂有多么伟大，您都可以登录scishowfinds.com。
and if you ever order something from there for yourself, or as a present for someone that you like, just know that you're supporting SciShow when you do it.
无论是为自己还是他人而在这里购买礼品，都是对《太空科学秀》的大力支持。
