Distant Quasar Is Early Universe's Brightest Object
| The light from this cosmic beacon took 12.9 billion years to reach Earth, but the sight was worth the wait. Astronomers say it is the most distant quasar, a massive black hole surrounded by luminous gas, that they have ever seen as well as the brightest object to be sighted in the early universe. Its distance means astronomers are seeing it blazing away at a time when the universe was merely 770 million years old, a team reports online today in Nature. The quasar's brilliance is powered by a monstrous black hole at its center that's 2 billion times more massive than the sun. The energy radiating from it would have contributed to the last phase of reionization of the early universe, the process that helped clear away the hydrogen fog shrouding the infant cosmos. More distant objects have been spotted in recent years, such as a gamma ray burst and a galaxy more than 13 billion light-years away, but this quasar is hundreds of times more luminous. |
來自這座宇宙燈塔的光線花了129億年的時間才到達地球，但是這一景觀值得等待。天文學家們稱，這是他們所觀察到的最遙遠的類星體，是一個被發光氣體環繞的巨型黑洞，也是早期宇宙中最為明亮的天體。今天，一個研究小組在《自然》雜志在線版上報道說：該類星體所處的遙遠距離意味著，天文學家們正在看到的是它在宇宙只有7.7億年時所發出的光。這個類星體發光所需的能量是由其中心的一個巨型黑洞提供的， 這個黑洞比太陽大20億倍。它所散發出來的能量可能促進了早期宇宙中再電離進入最后階段，這個過程幫助清除了彌漫于早期宇宙中的氫霧。近年來發現了更多的遙遠天體，比如一次伽馬射線爆發和一個130億光年之外的星系，但是這個類星體要明亮幾百倍。 |
