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. |
来自这座宇宙灯塔的光线花了129亿年的时间才到达地球，但是这一景观值得等待。天文学家们称，这是他们所观察到的最遥远的类星体，是一个被发光气体环绕的巨型黑洞，也是早期宇宙中最为明亮的天体。今天，一个研究小组在《自然》杂志在线版上报道说：该类星体所处的遥远距离意味着，天文学家们正在看到的是它在宇宙只有7.7亿年时所发出的光。这个类星体发光所需的能量是由其中心的一个巨型黑洞提供的， 这个黑洞比太阳大20亿倍。它所散发出来的能量可能促进了早期宇宙中再电离进入最后阶段，这个过程帮助清除了弥漫于早期宇宙中的氢雾。近年来发现了更多的遥远天体，比如一次伽马射线爆发和一个130亿光年之外的星系，但是这个类星体要明亮几百倍。 |
