In a wild galaxy over half a billion light-years away, astronomers have detected molecular oxygen.
在5億光年之外的一個野生星系中，天文學家探測到了分子氧。
It's only the third such detection ever outside the Solar System - and the first outside the Milky Way.
這只是太陽系以外的第三次這樣的探測-也是銀河系以外的第一次。
Oxygen is the third most abundant element in the Universe, behind hydrogen (naturally) and helium.
氧是宇宙中第三豐富的元素，僅次於氫(自然)和氦。
So its chemistry and abundance in interstellar clouds are important for understanding the role of molecular gas in galaxies.
因此它的化學成分和星際雲中的丰度對於理解分子氣體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.
天文學家一次又一次地尋找氧氣，使用毫米天文學和光譜學，前者探測分子發射的無線電波，後者分析光譜以尋找特定分子吸收或發射的波長。
But these searches have turned up a puzzling lack of oxygen molecules.
但這些搜索發現了令人費解的氧氣分子缺乏。
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.
這意味著“關於不同星際環境中氧化學的全面圖片仍然缺失”，由中國科學院王俊志領導的一組天文學家在一篇新的論文中寫道。
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.
已經檢測到分子氧的一個地方是獵戶座星雲；假設在太空中，氧與氫以水冰的形式結合在一起，附著在塵埃顆粒上。
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.
但是獵戶座星雲是一個恆星育兒室，來自非常熱的年輕恆星的強烈輻射有可能衝擊水冰，使其昇華並分裂分子，釋放氧氣。
Which brings us to a galaxy called Markarian 231.
這就把我們帶到了一個叫做馬卡里安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.
它距離地球5.61億光年，由類星體提供動力。
That's an extremely luminous galactic nucleus with an active supermassive black hole in the centre.
這是一個非常明亮的星系核，中心有一個活躍的超大質量黑洞。
They're the brightest objects in the Universe, and Markarian 231 contains the closest quasar to Earth.
它們是宇宙中最明亮的物體，而馬卡里安231包含了最接近地球的類星體。
In fact, astronomers think Markarian 231 might have two active supermassive black holes in its centre, whirling around each other at a furious rate.
事實上，天文學家認為馬卡里安231可能在其中心有兩個活躍的超大質量黑洞，以極快的速度彼此旋轉。
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