2017年托福听力科学美国人60秒：黑洞三兄弟2017-07-27 16:53 来源：网络综合
This is Scientific American 60 Secomds, Space. I'm Clara Moskowitz, got a minute?
Inside most galaxies a supermassive black hole lurks. But one galaxy about 4 billion light-years from us was recently discovered to have not one, not even two, but three gigantic black holes at its center.
Such triple systems appear to be extremely rare—only four are known. The newfound system includes two black holes orbiting each other very closely, about 450 light-years apart, with a third black hole a bit farther out. The central pair zoom around each other at a fast clip, about 300 times the speed of sound on Earth. The hole trinity also represents the tightest trio of black holes known to date. It's described in thejournal Nature.
As these objects continue to orbit at the center of their galaxy, gravity will eventually pull them closerand closer together. Ultimately, they may even merge. Researchers hope this triple-black-hole system may be a good place to look for space-time ripples called gravitational waves. As their orbits shrink, the black holes should radiate away some of their orbital energy as the sought-after gravitational waves, predicted by Einstein a century ago.
Thanks for the minute for Scientific American 60 Secomds, Tech. I'm Clara Moskowitz.