Brightest Galaxy 最亮的星系
Our galaxy, the Milky Way, is bigger and brighter than most others. Its hundreds of billions of stars emit roughly 20 billion times the light of the Sun. But a few rare galaxies make our galactic home seem modest. The brightest galaxy yet seen, for example, is 10,000 times brighter than the entire Milky Way.
This brilliant galaxy, which is identified only by a catalog name, is in the faint constellation Aquarius, which is low in the southeast at nightfall on these early autumn nights.
The galaxy is about 12-and-a-half billion light-years away, so we see it as it was when the universe was just 1.3 billion years old.
The galaxy owes most of its brilliance not to its stars, but to a black hole. A supermassive black hole at the galaxy's center attracts gas. As the gas plunges in, it gets so hot that it radiates profusely. Dust blocks our view of the galaxy, but the dust itself gets heated and emits infrared light. In fact, astronomers discovered the galaxy with an infrared telescope in space.
这一星系之所以能如此闪耀并非因为它的恒星，而是主要归功于黑洞，一个位于星系中心的巨型黑洞。当有气体进入时就会变得非常热，使其辐射增强。尘埃阻挡了我们观察这一星系的视线，但是尘埃本身也被加热并释放出红外光。实际上，天文学家就是通过空间红外望远镜发现这一星系的。 We can’t see what the galaxy looks like today. But it led such an accelerated lifestyle in its youth that it probably blew away much of its gas and converted the rest into stars. As a result, today it may be a dull type of galaxy known as a giant elliptical. If so, then it has no gas, no young stars, and no evidence that it once reigned as one of the brightest galaxies in the cosmos.