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***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