Black holes on a collision course
趋于碰撞的黑洞
Scientists say Chandra provides first evidence that two such mysteries can coexist in one galaxy. 科学家说，钱德拉望远镜首次证实两个黑洞可共存于同一星系中。
In a very bright galaxy 400 million light-years away, two black holes are drifting toward each other and in millions of years will merge with an eruption of energy and a burst of gravitational waves that could warp the very fabric of space, astronomers said Tuesday. 天文学家本周二说，在一个距地球4亿光年的明亮星系内，两个黑洞正在互相靠近，数百万年后将融为一体，并爆发出大量的能量，由此产生的引力波可能会影响到宇宙的每一个角落。
THE SCIENTISTS said the Chandra X-ray Observatory has found the first evidence that two immense black holes can coexist in the same galaxy and that they are moving toward each other for an eventual merger. 《科学家》说，钱德拉X线望远镜已经发现初步证据，证明两个巨大的黑洞可以同时存在于同一星系中，它们正在彼此靠拢，最终将合二为一。
The double black holes were found in a bright, highly active galaxy known as NGC6240, about 400 million light-years from the Earth. 这对黑洞存在于一个极其活跃明亮的星系中，该星系被命名为NGC6240，它距地球约有4亿光年。
Astronomers studied NGC6240 because it produced unexplained bursts of X-rays that appeared to come from one of two nuclei at the galactic center. Images collected by radio, infrared and optical observations showed two bright spots, but did not pinpoint the origin of the X-rays. 天文学家之所以研究NGC6240，是因为发现该星系中心有两个核，其中一个不断爆发出难以解释的X线。由无线电、红外线和光学观察收集到的影像显示该星系中有两个亮点，但无法准确定位X线的来源。
When Chandra, with its sensitive X-ray detectors, focused on the nuclei, astronomers hoped it would tell them whether either of the two points of activity were black holes. 钱德拉装有敏感的X线检测器，天文学家用它对准这星系的核心，希望确定两个活跃点中是否有一个为黑洞。
"Much to our surprise, we found that both were active black holes," Stefanie Komossa of the Max Planck Institute in Germany, said in a statement. 德国Max Planck研究所的Stefanie Komossa在一份申明中说："我们惊讶地发现它俩都是活跃的黑洞。"
Finding two black holes in one galaxy, said Komossa, "supports the idea that black holes can grow to enormous masses in the centers of galaxies by merging with other black holes." Komossa说，同一星系两洞并存的科学发现证明，星系核心的黑洞可以通过相互兼并融合而发展为宏大的物质。
An artist's conception shows two black holes whirling around each other at the center of a galaxy. 艺术化的构想是：这两个黑洞在星系中心互相围绕对方旋转。
Guenther Hasinger, also of Max Planck, said the Chandra images captured the unmistakable markings of two black holes - high-energy photons swirling around the dense black hole centers and X-rays spewing out from iron atoms being pulled into the center at a high rate of speed. Max Planck的Guenther Hasinger说，钱德拉所摄的影像捕获了可以确定两个黑洞并存的迹象，即在密度甚高的黑洞中心周围涡动着高能量的光子，从铁原子中喷射出的X线被高速吸入黑洞中心。
Komossa and Hasinger are co-authors of a study submitted for publication in the Astrophysical Journal Letters. Hasinger和Komossa曾联名撰文发表在《天文物理学通讯》上。
The two black holes in NGC6240 are now about 3,000 light-years apart and are expected to merge some time in the next few hundred million years, the researchers said. The merger will be accompanied by an eruption of radiation and a burst of gravitational waves that will spread throughout the universe, causing ripples in the fabric of space, the astronomers said. 据研究人员介绍，NGC6240中的两个黑洞目前相距大约3000光年，预计要几亿年后才能彼此融合，届时将会产生大量的辐射和引力波，冲击宇宙各处，造成太空的涟漪。
The gravitational ripples could cause minute changes in the distance between any two points in the universe, they said. 天文学家说，这种引力涟漪会使宇宙中任何两点间的距离发生细微的变化。
In another study, French and Argentine astronomers said that observations by the Hubble Space Telescope and ground-based telescopes have detected a stellar black hole streaking across the Milky Way at about 250,000 miles an hour. A companion star is being dragged along and slowly devoured by the black hole, according to scientists at the French Atomic Energy Commission and the Institute for Astronomy and Space Physics in Argentina. 在另一项研究中，法国和阿根廷天文学家说，通过哈勃太空望远镜和地面的天文望远镜，他们发现一个星球的黑洞正以25万英里的时速穿越银河系。据法国原子能委员会和阿根廷天文和空间物理研究所的科学家介绍，这个黑洞后还有另一颗星尾随相伴，并正在被黑洞慢慢地蚕食。
The astronomers said the stellar black hole may have been created by an exploding star in the inner disk of the Milky Way. The black hole is 6,000 to 9,000 light years away, the researchers said. A report on the observations appears Tuesday in the journal Astronomy and Astrophysics.
A black hole is a point in space that is so dense with matter that its gravitational field will not let anything - not even light - escape. Stellar black holes, equal to 3.5 to about 15 solar masses, can be formed by the collapse of a single massive star. But galactic black holes, such as those in NGC6240, are much larger, equal perhaps to millions of solar masses, and are usually at the center of galaxies.The Milky Way, home galaxy of the sun and its planets, is thought to have a black hole at its center.With its immense gravitational pull, a black hole can suck in gas, dust and other matter from the surrounding space. Entire stars can be stripped and pulled into the bottomless maw. As it spirals in at near light speeds, matter captured by a black hole heats by millions of degrees and gives out intense radiation in several parts of the spectrum, including X-rays. The orbiting Chandra observatory is able to detect these X-rays and relay the data to Earth for study by astronomers. 黑洞就是太空中的一个点，此点密度甚高，使得任何物质甚至光都无法脱离它的引力。一个巨星的瓦解就足以产生质量相当于3.5至15个太阳的星球黑洞。但星系黑洞如NGC6240中的黑洞要大得多，质量相当于几百万个太阳，通常位于星系的中心。 银河系是太阳及其九大行星的家，科学家认为银河系的中心就存在着一个黑洞。靠着强大的引力牵拉，黑洞能吸入来自周围空间的气体、尘埃和其它物质。这个无底洞甚至将整个星球分解后吸入。物质被黑洞捕获后以几近光速的高速被旋转吸入洞中时，它所释放出的热量可高达几百万度，并可发出不同的强烈射线，包括X射线。正在轨道上运转的钱德拉望远镜可以检测到这些X射线，并将数据传回地球，供天文学家研究。
NASA's Chandra X-ray Observatory was launched and deployed by the space shuttle Columbia on July 23, 1999. 美国航空航天局的钱德拉X线望远镜是在1999年7月23日，由哥伦比亚号太空飞船搭载发射升空的。
生命的循环
Facing death, Jeff Cross and Lily Cheng had run out of options. But a rare "domino" liver transplant, involving a living donor, gave both a future.
面对死亡，杰夫·克罗斯和程莉莉已经没有其他选择了。但是一个罕见的"多米诺"式肝脏移植(涉及到一位活人器官捐献者)，却给两人带来了新的生机。
Circle of Life
Since last spring, Jeff Cross, 29, had been tormented by night sweats, a side effect of the rare genetic illness that threatened to kill him unless he got a new liver
