| A giant black hole in the constellation Draco bit off more than it could chew. On 25 March, NASA's Swift satellite detected an x-ray flare when a black hole 3.9 billion light-years from Earth tore a passing star to shreds. The flare arose because friction and gravity roasted the star's remains and made them glow brilliantly before the black hole swallowed them. Now, as astronomers report online today in Nature, the x-ray dataas well as radio observations indicate the fireworks caused a narrow jet of material to shoot away from the black hole's outskirts. Similar jets emerge from other black holes, but this is the first time that astronomers have witnessed the birth of one. The black hole in Draco resides at the center of a far-off galaxy and is about the same size as the 4-million-solar-mass black hole marking the Milky Way's heart. Although our galaxy's black hole is currently quiet, this discovery means just one wayward star can spark a spectacle. | 天龙座的一个巨型黑洞吞食了太多的东西，造成了无法消化的现象。3月25日，当距离地球39亿光年的一个黑洞将一颗过往的恒星撕成碎片时，美国国家航空航天管理局的“雨燕”号卫星探测到X射线爆发。X射线爆发的产生是因为摩擦力和重力产生的热量烘烤着恒星的残余物，致使残余物发出明亮的光，然后被黑洞吞噬掉。目前，就像天文学家们今天在《自然》杂志在线版上报道的那样，X射线资料和射电观测资料显示，发光的残余物引起一股细细的物质射流从黑洞的边缘处射出。其他黑洞也射出同样的射流，但是这一次天文学家们首次目睹了黑洞射流的诞生。天龙座位于一个遥远星系的中心，质量大约跟代表着银河系中心的那个黑洞相当，相当于太阳质量的400万倍。尽管我们银河系的黑洞目前很安静，但是该发现意味着仅仅凭着一颗不规则的恒星就可以引起一派壮观的景象。 |
