http://www.astronomy.com/asy/default.aspx?c=a&id=6468
January 10, 2008
NASA's Hubble Space Telescope has revealed a never-before-seen optical alignment in space: a pair of glowing rings, one nestled inside the other like a bull's eye pattern. The double-ring pattern is caused by the other complex bending of light from two distant galaxies directly behind a foreground massive galaxy, like three beads on a string.
More than just a novelty, this very rare phenomenon can offer insights into dark matter, dark energy, the nature of distant galaxies, and even the curvature of the universe.
The phenomenon, called gravitational lensing, occurs when a massive galaxy in the foreground bends the light rays from a distant galaxy behind it, in much the same way as a magnifying glass would. When both galaxies are exactly lined up, the light forms a circle, called an "Einstein ring," around the foreground galaxy. If another background galaxy lies precisely on the same sightline, a second, larger ring will appear.
Because the odds of seeing such a special alignment are estimated to be one in 10,000, Tommaso says that they "hit the jackpot." The odds of seeing this phenomenon are less than winning two consecutive bets on a single number at Roulette.
要考英语了，看那些没营养的资料不如看这个，翻译了一下。试图尽量生动些，不太严谨之处见谅
这一前所未闻的太空光学对叠现象得到哈勃望远镜的见证：一对镶套在一起的耀眼指环，犹如一只太空明眸。这只巨眼里藏有三个星系：前景星系背后遥远处藏着一个，更远处呆着另一个。后面的两个家伙发出的光经过弯折后共同打造了这只双环。三个星系坐落得就像宇宙中一只指向我们的豆荚里的三颗豌豆。
双环并未打算任其意义止步于了它的传奇性。如此罕见的现象不仅能为我们叩开暗物质能量及遥远星系的大门，甚至涉及到宇宙自身的弯曲。
此现象被称作引力透镜效应——星系射出的光邂逅另一大块头星系时被强行折弯——就像放大镜们干的那样。如果两个星系正一前一后“向前看齐”地冲着我们，后面的那家伙看上去就是一个环，叫做“爱因斯坦环”，暧昧地绕着前面的伙计。万一队尾还藏着第三个星系，它是躲不掉变身为指环的命运的，而且很不幸地会被粗壮些的手指看上。
星系们以如此稀奇的方式排列的几率大概在0.01%，托马索直呼他们“中了大奖！”。的确，比较起来，期待轮盘赌桌上一个号码的连续两次中彩似乎更为人道些。 |
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