In a wild galaxy over half a billion light-years away, astronomers have detected molecular oxygen.
在5亿光年之外的一个野生星系中，天文学家探测到了分子氧。
It's only the third such detection ever outside the Solar System - and the first outside the Milky Way.
这只是太阳系以外的第三次这样的探测-也是银河系以外的第一次。
Oxygen is the third most abundant element in the Universe, behind hydrogen (naturally) and helium.
氧是宇宙中第三丰富的元素，仅次于氢(自然)和氦。
So its chemistry and abundance in interstellar clouds are important for understanding the role of molecular gas in galaxies.
因此它的化学成分和星际云中的丰度对于理解分子气体在星系中的作用是很重要的。
Astronomers have searched for oxygen again and again, using millimetre astronomy, which detects the radio wavelengths emitted by molecules; and spectroscopy, which analyses the spectrum to look for wavelengths absorbed or emitted by specific molecules.
天文学家一次又一次地寻找氧气，使用毫米天文学和光谱学，前者探测分子发射的无线电波，后者分析光谱以寻找特定分子吸收或发射的波长。
But these searches have turned up a puzzling lack of oxygen molecules.
但这些搜索发现了令人费解的氧气分子缺乏。
Which means "a comprehensive picture of oxygen chemistry in different interstellar environments is still missing," wrote a team of astronomers led by Junzhi Wang of the Chinese Academy of Sciences in a new paper.
这意味着“关于不同星际环境中氧化学的全面图片仍然缺失”，由中国科学院王俊志领导的一组天文学家在一篇新的论文中写道。
One place molecular oxygen has been detected is the Orion nebula; it's been hypothesised that out in space, oxygen is bound up with hydrogen in the form of water ice that is clinging to dust grains.
已经检测到分子氧的一个地方是猎户座星云；假设在太空中，氧与氢以水冰的形式结合在一起，附着在尘埃颗粒上。
But the Orion nebula is a stellar nursery, and it's possible that the intense radiation from very hot young stars shocks the water ice into sublimation and splits the molecules, releasing the oxygen.
但是猎户座星云是一个恒星育儿室，来自非常热的年轻恒星的强烈辐射有可能冲击水冰，使其升华并分裂分子，释放氧气。
Which brings us to a galaxy called Markarian 231.
这就把我们带到了一个叫做马卡里安231的星系。
Markarian 231 is special.
Markarian 231是特殊的。
It's 561 million light-years away, and powered by a quasar.
它距离地球5.61亿光年，由类星体提供动力。
That's an extremely luminous galactic nucleus with an active supermassive black hole in the centre.
这是一个非常明亮的星系核，中心有一个活跃的超大质量黑洞。
They're the brightest objects in the Universe, and Markarian 231 contains the closest quasar to Earth.
它们是宇宙中最明亮的物体，而马卡里安231包含了最接近地球的类星体。
In fact, astronomers think Markarian 231 might have two active supermassive black holes in its centre, whirling around each other at a furious rate.
事实上，天文学家认为马卡里安231可能在其中心有两个活跃的超大质量黑洞，以极快的速度彼此旋转。
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