可以吞没太阳系的黑洞（图）  

The Solar System Swallower

by Govert Schilling  胡德良 

 未来的望远镜可能会揭示星系M87中巨型黑洞的暗色轮廓，就象图中艺术家所描绘的那样，还会揭示出黑洞的射流，射流由高能粒子和辐射构成。

SEATTLE, WASHINGTON—Even among cosmic heavyweights, the black hole in the core of galaxy M87 stands out. New observations reveal that the object weighs in at a whopping 6.6 billion suns, making it the most massive black hole for which a precise mass has ever been measured. "It could swallow our solar system whole," says astronomer Karl Gebhardt of the University of Texas, Austin, who presented the new results here Wednesday afternoon at the 217th meeting of the American Astronomical Society.	尽管宇宙中拥有诸多重量级黑洞，但是星系M87中心的黑洞仍然脱颖而出。新一轮观测显示该黑洞的质量异常庞大，相当于太阳质量的66亿倍，成为质量最大的黑洞，因而研究人员对其质量进行了精确的测量。“它可以将我们的太阳系整个地吞下去，”德克萨斯大学奥斯汀分校的天文学家卡尔·格布哈特说。星期三下午，格布哈特将这项新的研究成果提交到在西雅图举行的美国天文学会第217次会议上。
Previous estimates put the mass of the black hole at some 3 billion times the mass of our sun, still nearly 1000 times as massive as the black hole at the center of the Milky Way. To compensate for the blurring effects of Earth's atmosphere and obtain a more accurate measurement, Gebhardt and colleagues utilized the adaptive optics capability of the 8.1-meter Frederick C. Gillett Gemini Telescope on Mauna Kea, Hawaii. That enabled the astronomers to measure how fast stars orbit the black hole, which lies some 50 million light-years away, in the direction of the constellation Virgo. From the observed speeds—up to almost 500 kilometers per second—they could then calculate the hole's mass. "It's the most accurate mass estimate ever obtained" for a supermassive black hole, says Gebhardt.	根据以前估计，这个黑洞的质量大约相当于我们太阳质量的30亿倍。即使如此，仍然是银河系中心黑洞的近1000倍。为了弥补地球大气的模糊效果所带来的缺憾，获得更为精确的测量结果，格布哈特及同事利用了夏威夷州莫纳克亚山上8.1米双子望远镜，该望远镜具有光学适应能力。这样，即使该黑洞位于室女座方向大约5000万光年之外，天文学家们也可以测量黑洞周边恒星的速度是多少。根据所观测到的速度——几乎高达每秒钟500公里，天文学家们可以计算出该黑洞的质量。“对于超级黑洞，这是所得到的最为精确的估算，”格布哈特说。
Gebhardt says the black hole's event horizon—the edge from within nothing can escape, not even light—is four times as large as the orbit of Neptune, the outermost planet in our solar system.	格布哈特称，该黑洞的视界——任何物质、甚至连光也无法从中逃逸的黑洞边界，相当于我们太阳系最外围的行星海王星轨道的四倍之大。
Supermassive black holes like the one in galaxy M87 probably grow not only by feeding on infalling gas and stars but also by mergers of smaller black holes. Astronomer George Djorgovski of the California Institute of Technology in Pasadena used adaptive optics on the 10-meter Keck telescope, also on Mauna Kea, to reveal orbiting pairs of black holes in 16 distant galaxies. "I expect them to merge within a few million years from now," he says.	象M87中这样的超级黑洞，它们的发展很可能不仅仅是依靠吞进流入的气体和恒星，而且也依靠吞并较小的黑洞。帕萨迪纳市加州理工学院的天文学家乔治·德尤戈夫斯基利用10米凯克望远镜上具有适应性的光学仪器，发现了在16个远处的星系中有一些黑洞在围绕着这个超级黑洞旋转。凯克望远镜也位于莫纳克亚山上。他说：“我预料，几百万年之后这些黑洞将被吞并于其中。”
Djorgovski, who also presented his results at the Seattle meeting, suspects that M87—by far the largest and most massive galaxy in the nearby universe—may be the result of successive mergers of about a hundred smaller galactic building blocks. Stellar motions in the core of the giant galaxy do indeed suggest that it may have experienced a black hole merger in the not-too-distant past, says Gebhardt.	德尤戈夫斯基也将他的研究结果提交到西雅图会议上。他认为：在附近的宇宙中，星系M87是体积最大、质量最大的星系，可能是相继吞并了大约一百个较小的星系作为构筑材料而形成的。格布哈特说，在这个巨大星系的中心，恒星的运动的确说明，在不太遥远的过去该星系有可能经历过一次吞并黑洞的事件。
Finding the most massive black hole isn't just a highlight for the record books. Gebhardt says studying extreme black holes like the one in M87 gives astronomers their best chance of learning more about black hole physics in general. "In fact," he says, "future observations of this object might finally help us prove that what we call black holes are really black holes. Until now, there has been no direct observational evidence at all for the existence of event horizons," which are the true signatures of black holes.	发现质量最大的黑洞不仅仅在记录册上是一个亮点。格布哈特指出，研究象星系M87中这样的超级黑洞可以为天文学家们提供最佳机会，使他们在整体上对黑洞的物理特性了解得更多。“事实上，”他说，“或许，将来对于这个黑洞的观测最终可以帮助我们证明这一点：我们所谓的黑洞才是真正意义上的黑洞。到目前为止，根本不存在直接的观测证据可以证实‘视界’的存在，而视界恰恰是黑洞真正的特征。”
That may change within 10 years or so, when astronomers hope to succeed in hooking up telescopes from all over the world that observe the universe at wavelengths shorter than 1 millimeter. According to Gebhardt, using such a "whole Earth submillimeter interferometer" may actually detect the silhouette of the black hole's event horizon against the galaxy's background glow.	这种状况在十年左右的时间内可以改变，届时天文学家们希望能够联合全世界的望远镜，来观测波长不超过1毫米的宇宙物质。据格布哈特说，这样利用“全球的亚毫米波干涉仪”，有可能真正地探测到这个黑洞视界的轮廓显现于星系的背景光之中。

译自：美国《科学》杂志网站（13 January 2011, 11:50 AM）

原著：Govert Schilling